- Email: [email protected]
Remote Monitoring and Control of an Electric Powered Wheelchair in an Assisted Living Environment
November 6-9, 2016. UFRGS, Porto Alegre, RS, Brazil 4th 4th IFAC IFAC Symposium Symposium on on Telematics Telematics Applications Applications 4th IFAC Symposium on Telematics Applications November 6-9, 2016. UFRGS, RS, Available online at www.sciencedirect.com November 6-9, 2016. UFRGS, Porto Porto Alegre, Alegre, RS, Brazil Brazil November 6-9, 2016. UFRGS, Porto Alegre, RS, Brazil
ScienceDirect IFAC-PapersOnLine (2016) 181–185 Remote Monitoring and Control 49-30 of an Electric Powered Wheelchair in an Remote Monitoring and Control of an Electric Powered Wheelchair in an Remote Monitoring and Control of an Electric Assisted Living Remote Monitoring and Control of anEnvironment Electric Powered Powered Wheelchair Wheelchair in in an an Assisted Living Environment Assisted Living Environment Assisted Living Victor L. Valenzuela* andEnvironment Vicente F. de Lucena, Jr**
Victor L. Valenzuela* and Vicente F. de Lucena, Jr** Victor Victor L. L. Valenzuela* Valenzuela* and and Vicente Vicente F. F. de de Lucena, Lucena, Jr** Jr** - IATECAM, Manaus, AM 69060-590 Brazil (e-mail: *Environmental and Technological Institute of the Amazon [email protected]) *Environmental and Institute of the Amazon -- IATECAM, Manaus, AM 69060-590 Brazil (e-mail: *Environmental and Technological Technological Institute of Manaus, AM 69060-590 *Environmental Technological Institute of the the Amazon Amazon - IATECAM, IATECAM, Manaus, AM 69060-590 Brazil Brazil (e-mail: (e-mail: ** Federaland University of Amazonas, Manaus, AM 69077-000 Brazil (e-mail: [email protected]) [email protected]) [email protected]) [email protected]) ** Federal University of Amazonas, Manaus, AM 69077-000 Brazil (e-mail: [email protected]) ** ** Federal Federal University University of of Amazonas, Amazonas, Manaus, Manaus, AM AM 69077-000 69077-000 Brazil Brazil (e-mail: (e-mail: [email protected]) [email protected])
Abstract: Ambient Intelligence can be defined as an evolution from the conventional automation systems, which are a Intelligence set of computers, sensors andas actuators that ubiquitously and pervasively have the Abstract: Ambient can be defined an evolution from the conventional automation Abstract: Ambient Intelligence can be defined as an evolution from conventional automation Abstract: Ambient Intelligence can of be defined asactuators an evolution from the the derivation conventional automation purpose of facilitate the execution daily tasks. One very important from Ambient systems, which are a set of computers, sensors and that ubiquitously and pervasively have the systems, which are aa set of computers, sensors and actuators that and pervasively have the systems, which are set of execution computers, sensors and actuators that ubiquitously ubiquitously and pervasively have the Intelligence are the Assisted Living Environments that are complex systems designed to help people purpose of facilitate the of daily tasks. One very important derivation from Ambient purpose of facilitate the execution of daily tasks. One very important derivation from Ambient purpose of facilitate the execution of daily tasks. One very important derivation from Ambient interacting with other devices. Living The impact of such systems in complex everyday systems life is more easily observed when Intelligence are the Assisted Environments that are designed to help people Intelligence are the Assisted Living Environments that are complex systems designed to help Intelligence are thewith Assisted Living Environments that complex systems designed toModifications help people people talking about users disabilities. That isof the case of theare project described in this paper.observed interacting with other devices. The impact such systems in everyday life is more easily when interacting with other devices. The impact of such systems in everyday life is more easily observed when interacting with other devices. The impact such everyday is in more easily when were made tousers an electric-powered wheelchair in systems order enable its life remote control byobserved using mobile talking about with disabilities. That isofthe case of thetoin project described this paper. Modifications talking about users with That the case of described in this paper. Modifications talking about users with disabilities. disabilities. That is is on thethe case of the thetoproject project described inand thisaimed paper. Modifications devices. Those modifications have focused wheelchair control system to emulate it in were made to an electric-powered wheelchair in order enable its remote control by using mobile were made to electric-powered wheelchair in order to enable its remote control by mobile were made to an an electric-powered wheelchair in orderthe to wheelchair. enable itssystem remote control byto using using mobile software so that Smartphones and Tablets could control Details of the developed system, devices. Those modifications have focused on the wheelchair control and aimed emulate it in devices. Those modifications have focused on the wheelchair control system and aimed to it devices. Those modifications have focused on the wheelchair control system and aimed to emulate emulate it in in with emphasis on the telematics control will be given along the paper. software so that Smartphones and Tablets could control the wheelchair. Details of the developed system, software so that Smartphones and Tablets could control the wheelchair. Details of the developed system, software so that Smartphones and Tablets could control the wheelchair. Details of the developed system, with emphasis on the telematics control will be givenControl) along the paper.by Elsevier Ltd. All rights reserved. with emphasis on control be along © 2016, IFAC (International Federation Automatic Hosting Keywords: Tele-Medicine and e-Health, Intelligent andpaper. Ambient Intelligence, Ambient Assisted with emphasis on the the telematics telematics controlofwill will be given given Homes along the the paper. Living, Automatic Electric-Powered Wheelchair, Telematics Control and Monitoring. Keywords: Tele-Medicine and e-Health, Intelligent Homes and Ambient Intelligence, Ambient Ambient Assisted Assisted Keywords: Tele-Medicine and e-Health, Intelligent Homes and Ambient Intelligence, Keywords: Tele-Medicine and e-Health, Intelligent Homes Control and Ambient Intelligence, Ambient Assisted Living, Automatic Electric-Powered Wheelchair, Telematics and Monitoring. Living, Automatic Electric-Powered Wheelchair, Telematics Control and Monitoring. Living, Automatic Electric-Powered Wheelchair, Telematics Control and Monitoring. Ambient Intelligence (AmI) can be defined as an evolution 1. INTRODUCTION from the conventional automation systems, which Ambient (AmI) can be defined as an evolution Ambient Intelligence Intelligence (AmI) be defined as evolution 1. INTRODUCTION 1. (AmI) can can be the defined as an an ubiquitously and pervasively have purpose of evolution facilitate One of the most important assistive technology equipment Ambient from the theIntelligence conventional automation systems, which 1. INTRODUCTION INTRODUCTION from conventional automation systems, which the and conventional systems, which the execution of dailyautomation tasks [Remagnino2005] created to increase the mobility oftechnology people with motor from ubiquitously pervasively have the purpose of facilitate One of the most important assistive equipment ubiquitously and pervasively have the purpose of facilitate One of the most important assistive technology equipment ubiquitously and pervasively have the purpose of facilitate One of the most important assistive technology equipment [Romero2008]. These new systems hold a high degree of disabilities is the electric-powered wheelchair, (Electrical the execution of daily tasks [Remagnino2005] created to increase the mobility of people with motor the execution of daily tasks [Remagnino2005] created to increase the of people motor the execution of new daily tasks [Remagnino2005] created to or increase the mobility mobility ofwheelchair, people with with motor [Romero2008]. automation processes and products, and mix different Wheelchair EPW). Depending on the disabilities, potential These systems hold a high degree of disabilities is the electric-powered (Electrical [Romero2008]. These new systems hold aa high degree of disabilities is the electric-powered wheelchair, (Electrical [Romero2008]. These new systems hold high degree of disabilities is EPW). theamong electric-powered wheelchair, (Electrical technologies, which exist individually today, in an inhabited users may choose a large number of available models. automation processes and products, and mix different Wheelchair or Depending on the disabilities, potential automation processes and products, and mix different Wheelchair or EPW). Depending on the disabilities, potential automation processes and products, and mix different Wheelchair or EPW). Depending on the disabilities, potential integrated environment [Garate2005] [Harwing2002]. The In some cases, the useraa large is strong enough to command technologies, which exist individually today, in an inhabited users may choose among number of available models. technologies, which exist individually today, in inhabited users may choose among number of models. technologies, which exist[Garate2005] individually today, in an ancapable inhabited users may cases, choose among a large large number of available available models. final objective is to provide automatized systems of movement trough joysticks or similar devices, in extreme integrated environment [Harwing2002]. The In some the user is strong enough to command integrated environment [Garate2005] [Harwing2002]. The In some cases, the user is strong enough to command integrated environment [Garate2005] [Harwing2002]. The In some cases, the user isoruse strong enough to command providing comfort, entertainment, nursing elderly and ill cases it is necessary to make of solutions that consider final objective is to provide automatized systems capable of movement trough joysticks similar devices, in extreme final objective is automatized systems capable of movement trough or similar devices, in extreme final objective is to to provide provide automatized systems capable of movement troughto joysticks joysticks oruse similar devices, in consider extreme inhabitants, environment security, resource economy (energy, biological signal control the movement of the EPW. In all providing comfort, entertainment, nursing elderly and ill cases it is necessary to make of solutions that providing comfort, entertainment, nursing elderly and ill cases it is necessary to make use of solutions that consider providing comfort, entertainment, nursing elderly and ill cases it is necessary to make use of solutions that consider water), and other functionalities that will adapt to the need of cases it is assumed that a customization of the EPW is inhabitants, environment security, resource economy (energy, biological signal to control the movement of the EPW. In all inhabitants, environment security, resource economy (energy, biological signal to control the movement of the EPW. In all inhabitants, environment security, resource economy (energy, biological signal to control the movement of the EPW. In all the human being in these environments [Verhaegh2006] needed, normally it means, among other details, the selection water), and other functionalities that will adapt to the need of cases it is assumed that aa customization of EPW is water), and other functionalities that to cases it is assumed that customization of EPW is and[Sanchez2008]. other functionalities that will will adapt adapt to the the need need of of cases it normally is sensor assumed that aamong customization of the the EPW is water), [Litz2007] of the right for human-machine interfaces and custom the human being in these environments [Verhaegh2006] needed, it means, other details, the selection the human being in these environments [Verhaegh2006] needed, normally it means, among other details, the selection the human being in these environments [Verhaegh2006] needed, normally it means, among other details, the selection regulation driving parameters. [Sanchez2008]. of the rightofsensor for human-machine interfaces and custom [Litz2007] [Litz2007] [Sanchez2008]. of the for human-machine To implement the concept of Ambient Intelligence it's [Sanchez2008]. of the right rightofsensor sensor forparameters. human-machine interfaces interfaces and and custom custom [Litz2007] regulation driving regulation of driving parameters. necessary to involve a great of quantity of technologies and In fact, there are reports about how difficult it is to drive a To implement the concept Ambient Intelligence it's regulation of driving parameters. To implement the of Ambient Intelligence it's To implement the concept concept of Ambient Intelligence it's areas of knowledge related to electronics and software EPWs, many users faced many problems to learn how to necessary to involve a great quantity of technologies and In fact, there are reports about how difficult it is to drive a necessary to involve a great quantity of technologies and In fact, there are reports about how difficult it is to drive a necessary to involve a great quantity of technologies and In fact, there are reports about how difficult it is to drive a development [vanHouten2008]. These were first researched control them, users while faced othersmany just cannot useto them properly areas of knowledge related to electronics and software EPWs, many problems learn how to areas of knowledge related to electronics and software EPWs, many users faced many problems to learn how to areas ofPhilips knowledge related toThese electronics andinresearched software EPWs, many users faced many problems to them learnaffect how the to by the Company in their R&D labs Holland [Fehr2000] [Simpson2008]. Some other diseases development [vanHouten2008]. were first control them, while others just cannot use properly development [vanHouten2008]. These were first researched control them, while others just cannot use them properly development [vanHouten2008]. These were first researched control them, while others just cannot use them properly [Ist2001]. In order to obtain the desired characteristics of patients’ condition along time reducing their motor ability. In by the Philips Company in their R&D labs in Holland [Fehr2000] [Simpson2008]. Some other diseases affect the by the Philips Company in their R&D labs in Holland [Fehr2000] [Simpson2008]. Some other diseases affect the by the Philips Company in their R&D labs in Holland [Fehr2000] [Simpson2008]. Some other diseases affect the Ambient Intelligence the knowhow of technologies like new these cases the patients may lose their driving skills leading [Ist2001]. In order to obtain the desired characteristics of patients’ condition along time reducing their motor ability. In [Ist2001]. In order the characteristics of patients’ condition along time reducing their motor ability. In [Ist2001].Intelligence In micro-electromechanical order to totheobtain obtain the desired desired characteristics of patients’ condition along time reducing their motor ability. In Ambient materials, systems, sensor to a necessary change of the EPWs control interface. In any knowhow of technologies like new these cases the patients may lose their driving skills leading Ambient Intelligence the knowhow of technologies like new these cases the patients may lose their driving skills leading Ambient Intelligence the knowhow of technologies like new these cases the patients may lose their driving skills leading technology, wireless communication, adaptive software, cases, driving tests withof potential users are necessary. materials, micro-electromechanical systems, sensor to aa necessary change the EPWs control interface. In any materials, micro-electromechanical systems, sensor to change of the control interface. materials, systems, micro-electromechanical systems, sensor to a necessary necessary change ofpotential the EPWs EPWs control interface. In In any any technology, embedded software agents, and the like, are needed wireless communication, adaptive software, cases, driving tests with users are necessary. technology, wireless communication, adaptive software, cases, driving tests with potential users are necessary. That why, tests for awith long time from many academic technology, wireless communication, adaptive software, cases,isdriving potential users now, are necessary. [Mukherjee2006]. embedded systems, software agents, and the like, are needed embedded systems, studies addressed design of EPW driving simulators embedded systems, software software agents, agents, and and the the like, like, are are needed needed That is why, for aathelong time from now, many academic That is why, for long time from now, many academic [Mukherjee2006]. [Mukherjee2006]. That is addressed why,[Pithon2009]. for athelong time from now, many academic The current technological scene has allowed for even smaller [Erren2007] The first simulators made use of [Mukherjee2006]. studies design of EPW driving simulators studies addressed the design of EPW driving simulators studies addressed the design of EPW drivingmade simulators equipment have morescene processing and for communication 2D representations for driving electric-powered wheelchairs The current current to technological scene has allowed allowed for even smaller smaller [Erren2007] [Pithon2009]. The first simulators use of The technological has even [Erren2007] [Pithon2009]. The first simulators made use of The current technological scene has allowed for even smaller [Erren2007] [Pithon2009]. The first simulators made use of power, and with that new applications can be proposed. [Lefkowicz1992] [Swan1994]. Recently the simulators are equipment to to have have more more processing processing and and communication communication 2D representations for driving electric-powered wheelchairs equipment 2D representations for driving electric-powered wheelchairs equipment to have more processing and communication 2D representations for driving electric-powered wheelchairs Sensors actuators can be connected in wireless networks developed in 3D. Among the most successful tools, there are power, and with that new applications can be proposed. [Lefkowicz1992] [Swan1994]. Recently the simulators power, and with that new applications can be proposed. [Lefkowicz1992] [Swan1994]. Recently the simulators are and with thatcan applications can be amount proposed. [Lefkowicz1992] [Swan1994]. Recently the and simulators are power, with little cost, making itnew possible to obtain a great of the Wheelsim [Rnt2008, Lifetool2008] Accessim Sensors and actuators be connected in wireless networks developed in 3D. Among the most successful tools, there are Sensors and actuators can be connected in wireless networks developed in 3D. Among the most successful tools, there are Sensors and actuators can be connected in wireless networks developed in 3D. Among the most successful tools, there are data to a specific ambient or process, and act upon them [Ceremh2011]. with little cost, making it possible to obtain a great amount of the Wheelsim [Rnt2008, Lifetool2008] and Accessim with little cost, making it to aa great amount of the Wheelsim little cost, making it possible possible to obtain obtain great amount of the Wheelsim [Rnt2008, [Rnt2008, Lifetool2008] Lifetool2008] and and Accessim Accessim with data to a specific ambient or process, and act upon them [Ceremh2011]. data to a specific ambient or process, and act upon them [Ceremh2011]. data to a specific ambient or process, and act upon them [Ceremh2011]. Copyright © 2016 IFAC 181 2405-8963 © 2016, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved. Copyright 2016 IFAC 181 Peer review© of International Federation of Automatic Copyright ©under 2016 responsibility IFAC 181Control. Copyright © 2016 IFAC 181 10.1016/j.ifacol.2016.11.164
2016 IFAC TA 182 November 6-9, 2016. Porto Alegre, BrazilVictor L. Valenzuela et al. / IFAC-PapersOnLine 49-30 (2016) 181–185
[Pauwels2007]. And all of this should occur without direct user intervention.
signals of the mechanical joystick; or add another node to the internal CAN bus. The first option requires a digital-toanalog converter to generate two voltage levels, which represent the displacement of the joystick on the X and Y axes. The signals connect to the analog-to-digital converter of the I-MCU to replicate the behavior of the joystick. The second options requires CAN bus interface to send commands to the P-MCU directly, instead of going through the I-MCU, and must use the same definition of messages as the P-MCU and I-MCU.
However, in order for an Ambient Intelligence scenario to become reality, only data collection is not enough. It's necessary to imbue the system with computational intelligence so it can process data on its own in order to infer in the context of them and still take into consideration the perspective of the human user [Becker2006]. With that it's possible to make the ambient reactive and adaptable to the needs of the users.
Beyond the Wi-Fi connection, both approaches require additional hardware from the remote control microcontroller (RC-MCU): a CAN controller, which may be internal or external, and an external CAN transceiver, or a digital-toanalog converter, which may also be internal or external. Fig. 2 provides an overview of the whole system and how each device connects to the other.
Fig. 1. Basic Architecture of the CRIAI Project. Fig. 2. Overview of devices that compose the system.
The CRIAI project is inserted in this context, which is a joint research initiative focused on the proposal of an AmI system designed to help people with disabilities. Fig. 1 contains the main components of this project. Sensors and actuators were properly distributed in a set of rooms. They are controlled by a residential automation system that is also properly connected to the consumer electronic devices. Central point is an EPW that was modified to receive commands via BCI or other mobile devices. That is a very important point in the proposed architecture as it is desired that the EPW navigate autonomously in a known ambient.
2.1 Joystick Emulation The joystick emulation approach requires three steps to correctly connect the signals to the I-MCU and allow the RCMCU to replace the joystick: identify the voltage levels generated by the joystick, design the connection between DAC and ADC, and define the equation that converts the joystick displacement to the value range of the DAC. The working principle of the joystick is shown in Fig. 3. The joystick can assume any position inside the circle formed by its mechanism. The voltage level of the outputs varies based on the position that is currently being held.
The main objective of this paper is to describe the modifications made to the electric wheelchair during the CRIAI Project. The sole purpose of these changes was to enable remote control of the wheelchair by using mobile devices. The modifications have focused on the control system and aimed to emulate it in software so that Smartphones and Tablets could control the wheelchair. 2. CONTROL APPROACHES The commercial EPW used in this work has two microcontrollers inside it: the interface microcontroller (I-MCU), which manages the buttons, the joystick and the LEDs that allow the user to interact with the EPW; and the power microcontroller (P-MCU), which has control of the motors and brakes, manages the battery and stores a few setup parameters. The two MCUs communicate with each other through CAN bus.
Fig. 3. Working principle of the joystick. After measuring the voltage level at the joystick output, the values shown in table 1 were acquired for both X and Y axes.
At a first glance, there are two different approaches to add another device to control the EPW: emulate the electrical 182
2016 IFAC TA November 6-9, 2016. Porto Alegre, BrazilVictor L. Valenzuela et al. / IFAC-PapersOnLine 49-30 (2016) 181–185
183
Table 1: The voltage levels for both X and Y axes. X axis
Y axis
Center value
2.3V
Center value
2.3V
Left
3.3V
Forward
2.3V
Right
1.37V
Backwards
1.37V
Ref. value
2.45V
In order to evaluate both approaches, the UDOO single-board computer was selected because it features a microcontroller and a microprocessor that fulfil the requirements defined at the beginning of section 2. The Atmel SAM3X8E has both a digital-to-analog converter and a CAN controller in the same die, but it does not have Wi-Fi transceiver, nor support for a full-featured Internet Protocol stack. However, the Freescale MCIMX6Q runs the Linux OS which then provides the means to remotely control the EPW via Wi-Fi. Thus, the RCMCU is composed of two devices mentioned above.
Fig. 5. Application interface and working principle to generate intensity values. The movement commands are generated with its respective intensity, as was done by the joystick, and the result is an array that contains the displacement in both X and Y axes. As previously mentioned, the X axis represents left and right and the Y axis represents forward and backward, therefore, to distinguish the directions on each axis, the intensity is represented by an integer number from -100 to 100. A positive number is interpreted as “left” on the X axis and “forward” on the Y axis, whereas a negative number is interpreted as the opposite direction for each axis. The table 2 shows how an array is composed, where Xi and Yi are the desired intensity value for that axis. As an example, the array X;50;Y;50 results in 50% intensity to the left and 50% intensity forward, whereas the array X;0;Y;-100 results in no X axis movement and 100% backwards.
The signal conditioning had to be developed around the voltage range provided by the DAC of the SAM3X8E, which is from 0.5V, at its lowest, to 2.8V, at its highest. Since the joystick operates inside the 1.3V to 3.3V range, a noninverting gain circuit was used, as shown in Fig. 4. The output of this circuit if given by the following formula: Vout = 1.2×Vin. The joystick also generated a voltage reference value as a mechanism to detect if it was working properly, as shown in table 1.
Table 2: The format of the data array received from the joystick application.
The connection of the DAC and ADC is done as follow: DAC0 and DAC1 connect to the pins of the same name on the SAM3X8E of the RC-MCU, which are the pins 66 and 67 on the UDOO; and JOY_X, JOY_Y, and JOY_VREF are connected to the pins that lead to the ADC of the I-MCU on the EPW.
byte
byte
byte
byte
byte
byte
byte
0
1
2
3
4
5
6
X
‘;’
Xi
‘;’
Y
‘;’
Yi
On the i.MX6Q of the RC-MCU, the software is responsible for receiving the data array from the remote application and converting the parameters to the values used by the SAM3X8E of the RC-MCU. This process is required because the DAC uses 8-bit values, i.e., to generate 2.8V, the 8-bit value input is 255, and to generate 0.5V, the 8-bit value input is 0. Thus, to emulate the range of the joystick, the 8-bit values shown in table 3 were used. Table 3: Voltage levels and their respective 8-bit values.
Fig. 4. Signal conditioning circuit. As mentioned at the beginning of this work, all movement commands are issued by an application running on a Smartphone or a Tablet and its interface is shown in Fig. 5. The communication between the application and the software running on the i.MX6Q of the RC-MCU is performed via TCP socket. 183
Position
Voltage
8-bit value
Center value
2.3V
152 (0x98)
Left/Forward
3.3V
250 (0xFA)
Right/Backwards
1.37V
58 (0x3E)
2016 IFAC TA 184 November 6-9, 2016. Porto Alegre, BrazilVictor L. Valenzuela et al. / IFAC-PapersOnLine 49-30 (2016) 181–185
Based on these values, the equation (1) was determined in order to convert the intensity values from -100 to 100 into the 8-bit values required by the DAC. Then, using the equation, the software running on the i.MX6Q uses the same array structure shown in table 2 to send to the SAM3X8E the data array with Xi and Yi replaced by the calculated 8-bit values. Using the same previous examples, the array X;50;Y;50 results in 199 for both X and Y axes, thus the new array is X;199;Y;199, whereas the array X;0;Y;-100 results in 152 for the X axis and 58 for the Y axis, thus the new array is X;152;Y;58.
Because the UDOO board has been deployed to this system, two options were designed to attach the RC-MCU to the CAN bus. As shown in Fig. 7, the CAN node can be managed by the i.MX6Q or by the SAM3X8E. The first option uses the SPI port to control an external CAN controller, the MCP2515, and uses the SN65HVD234D CAN transceiver. The second option uses the same external transceiver, but, instead of the MCP2515, it uses the internal CAN controller of the SAM3X8E. The test circuit is shown in Fig. 8.
(1)
Fig. 6. Diagram overview of the joystick emulation approach.
Fig. 7. Diagram overview of the network node inclusion approach.
In summary, for the first approach, in which the joystick is emulated, the system shown in Fig. 6 was achieved. This control solution was put under test to determine its performance and a few points have been noted:
The number of TCP hops in the Wi-Fi network interferes with operation of the EPW. If this number is too high and the network has high traffic, packages are either lost or delayed and real-time maneuvering is compromised.
The responsiveness is slightly minor than the stock, mechanical joystick and maneuvering the EPW at high speeds causes more crashes, but at lower speeds the difference in responsiveness is barely noticeable.
Manual operation is not possible because the emulated joystick uses the same ADC channels of the joystick. For safety purposes, both methods should be able to operate in parallel, which would require 4 ADC channels, but that is not available as default by the manufacturer.
Fig. 8. CAN controller and transceiver circuit.
2.1 Network node inclusion
Though this method was not fully tested, some assumptions can be made about its performance and features.
The network node inclusion approach also requires three steps to correctly connect the RC-MCU to the internal CAN bus of the EPW: map the message frames exchanged between P-MCU and I-MCU during normal operation, design the connection to the CAN bus, and define a procedure to convert the movement commands into the message frames used by both I-MCU and P-MCU. Most information regarding the method of communication, only the CAN bus connection was proposed and not entirely tested.
184
This control method is more expensive and more invasive, because it requires more components to be built and knowledge about the proprietary method of communication between P-MCU and I-MCU.
The responsiveness is similar to the joystick emulation method, because this issue is mainly caused by the WiFi network communication.
2016 IFAC TA November 6-9, 2016. Porto Alegre, BrazilVictor L. Valenzuela et al. / IFAC-PapersOnLine 49-30 (2016) 181–185
185
Harwig, R., and Aarts, E. (2002). Ambient Intelligence: invisible electronics emerging. Proc. of the IEEE Int. Conf. on Interconnect Technology, 2002.; pp. 3 – 5. IST Advisory Group (ISTAG) (2001). Ambient Intelligence: From Vision to Reality, European Commission, 2001. Lefkowicz, A.T. (1993). Validation of a PC-based perspective-view wheelchair simulator. Virginia Polytechnic Institute and State University. Lifetool Solutions. (2008). Lifetool: Wheelsim. In: http://www.lifetool-solutions.at/de/. Litz, L., and Gross, M. (2007). Covering Assisted Living Key Areas based on Home Automation Sensors; IEEE Int. Conf. on Networking, Sensing and Control, 15-17 April 2007, pp. 639 – 643. Mukherjee, S., Aarts, E., Roovers, R., Widdershoven, F., and Ouwerkerk, M. (2006). AmIware Hardware Technology Drivers of Ambient Intelligence, Philips Research Book Series, Springer, 480 p., 2006. Pauwels, E.J., Salah, A.A., and Tavenard, R. (2007). Sensor Networks for Ambient Intelligence, IEEE 9th Workshop on Multimedia Signal Processing MMSP 2007, 1-3 Oct. 2007, pp. 13 – 16. Pithon, T., Weiss, T., Richir, S., and Klinger, E. (2009). Wheelchairs simulators: a review. Technology and Disability, volume 21, pp. 1-10. Remagnino, P., and Foresti, G.L. (2005). Ambient Intelligence: A New Multidisciplinary Paradigm; IEEE Transactions on Systems, Man and Cybernetics, Part A, Vol. 35, Issue 1, pp. 1 – 6, Jan. 2005 RNT Association of Paralyse France. (2008). Wheelsim: a play of simulation of control in electric wheel chair. In: http://rnt.over-blog.com/article-21608792.html. Romero, M., Pousman, Z., amd Mateas, M. (2008) Alien presence in the home: the design of Tableau Machine; ACM Personal and Ubiquitous Computing; Vol. 12, Issue 5, June 2008, pp. 373 - 382. Sanchez, D., Tentori, M., and Favela, J. (2008). Activity Recognition for the Smart Hospital; IEEE Intelligent Systems, Vol. 23, Issue 2, March-April 2008 pp. 50 – 57. Simpson, R., Lopresti, E., and Cooper, R. (2008). How many people would benefit from a smart wheelchair. Journal of Rehabilitation Research and Development, vol. 45(1), pp. 53-72. Swan Li, J.E., Stredney, D., Carlson, W., and Blostein, B. (1994). The determination of wheelchair user proficiency and environmental accessibility through virtual simulation. Proc. of the 2nd Annual Int. Conf. Virtual Reality and Persons with Disabilities, page 156-161. van Houten, H. (2005) The physical layer of ambient intelligence, Int. Symp. on VLSI Technology, pp. 9 – 12. Verhaegh, W., Aarts, E., and Korst, J. (2006). Intelligent Algorithms in Ambient and Biomedical Computing, Philips Research Book Series, Springer, 320 p., 2006.
Manual operation is possible because the I-MCU and RC-MCU are independent and can simultaneously send commands to the P-MCU. Though the impact of simultaneous control was not tested. 3. CONCLUSION AND FUTURE WORK
Both control methods have its advantages and disadvantages, which are mainly cost, simplicity and safety. Given that the second approach was not fully tested, it is not possible to claim which of the two has better performance. However, at this stage, this remote control method helps nurses to take care of people with disabilities who are not able to drive themselves with the EPW, as they will not be required to push and maneuver it around. Moreover, the results of this work are the basis of two larger research projects. The first project is the CRIAI project, which was mentioned earlier. The second project uses the remotely-controlled EPW of this work in a safe environment for remote training and assessment of EPW driving skills, which will assist the rehabilitation of new wheelchair users. Finally, in order to improve the comfort of those being transported or those taking care, cameras may be added to the EPW to provide autonomous navigation and certified safety laser scanners may also be added to avoid collisions. ACKNOWLEDGEMENTS The authors would like to thank the Funding Authority for Studies and Projects (FINEP) Organization and the Environmental and Technological Institute of the Amazon (IATECAM) for the financial support, the Research and Development of Information and Electronics Technology Center (CETELI) for providing the infrastructure of laboratories and tools. REFERENCES Becker, M., Werkman, E., Anastasopoulos, M., and Kleinberger, T. (2006). Approaching Ambient Intelligent Home Care Systems; Pervasive Health Conference and Workshops, pp. 1 – 10; 2006. Ceremh - Center of Resources and Innovation Mobility and Handicap (CEREMH). (2011). The accessim project. In: http://www.ceremh.org/accessibilite/recherche-andinnovation-47/accessim/. Erren-Wolters et al. (2007). Virtual reality for mobility devices: training applications and clinical results: a review. International Journal of Rehabilitation Research, vol. 30, page 91-96. Fehr, L., Langbein, W., and Skaar, S. (2000). Adequacy of power wheelchair control interface for persons with severe disabilities: a clinical survey. Journal of Rehabilitation Research and Development, vol. 37(3). Garate, A., Lucas, I., Herrasti, N., and Lopez, A. (2005) Ambient intelligence as paradigm of a full automation process at home in a real application. Proc. of IEEE Int. Symposium on Computational Intelligence in Robotics and Automation, 2005. CIRA 2005., pp. 475 – 479.
185
ScienceDirect IFAC-PapersOnLine (2016) 181–185 Remote Monitoring and Control 49-30 of an Electric Powered Wheelchair in an Remote Monitoring and Control of an Electric Powered Wheelchair in an Remote Monitoring and Control of an Electric Assisted Living Remote Monitoring and Control of anEnvironment Electric Powered Powered Wheelchair Wheelchair in in an an Assisted Living Environment Assisted Living Environment Assisted Living Victor L. Valenzuela* andEnvironment Vicente F. de Lucena, Jr**
Victor L. Valenzuela* and Vicente F. de Lucena, Jr** Victor Victor L. L. Valenzuela* Valenzuela* and and Vicente Vicente F. F. de de Lucena, Lucena, Jr** Jr** - IATECAM, Manaus, AM 69060-590 Brazil (e-mail: *Environmental and Technological Institute of the Amazon [email protected]) *Environmental and Institute of the Amazon -- IATECAM, Manaus, AM 69060-590 Brazil (e-mail: *Environmental and Technological Technological Institute of Manaus, AM 69060-590 *Environmental Technological Institute of the the Amazon Amazon - IATECAM, IATECAM, Manaus, AM 69060-590 Brazil Brazil (e-mail: (e-mail: ** Federaland University of Amazonas, Manaus, AM 69077-000 Brazil (e-mail: [email protected]) [email protected]) [email protected]) [email protected]) ** Federal University of Amazonas, Manaus, AM 69077-000 Brazil (e-mail: [email protected]) ** ** Federal Federal University University of of Amazonas, Amazonas, Manaus, Manaus, AM AM 69077-000 69077-000 Brazil Brazil (e-mail: (e-mail: [email protected]) [email protected])
Abstract: Ambient Intelligence can be defined as an evolution from the conventional automation systems, which are a Intelligence set of computers, sensors andas actuators that ubiquitously and pervasively have the Abstract: Ambient can be defined an evolution from the conventional automation Abstract: Ambient Intelligence can be defined as an evolution from conventional automation Abstract: Ambient Intelligence can of be defined asactuators an evolution from the the derivation conventional automation purpose of facilitate the execution daily tasks. One very important from Ambient systems, which are a set of computers, sensors and that ubiquitously and pervasively have the systems, which are aa set of computers, sensors and actuators that and pervasively have the systems, which are set of execution computers, sensors and actuators that ubiquitously ubiquitously and pervasively have the Intelligence are the Assisted Living Environments that are complex systems designed to help people purpose of facilitate the of daily tasks. One very important derivation from Ambient purpose of facilitate the execution of daily tasks. One very important derivation from Ambient purpose of facilitate the execution of daily tasks. One very important derivation from Ambient interacting with other devices. Living The impact of such systems in complex everyday systems life is more easily observed when Intelligence are the Assisted Environments that are designed to help people Intelligence are the Assisted Living Environments that are complex systems designed to help Intelligence are thewith Assisted Living Environments that complex systems designed toModifications help people people talking about users disabilities. That isof the case of theare project described in this paper.observed interacting with other devices. The impact such systems in everyday life is more easily when interacting with other devices. The impact of such systems in everyday life is more easily observed when interacting with other devices. The impact such everyday is in more easily when were made tousers an electric-powered wheelchair in systems order enable its life remote control byobserved using mobile talking about with disabilities. That isofthe case of thetoin project described this paper. Modifications talking about users with That the case of described in this paper. Modifications talking about users with disabilities. disabilities. That is is on thethe case of the thetoproject project described inand thisaimed paper. Modifications devices. Those modifications have focused wheelchair control system to emulate it in were made to an electric-powered wheelchair in order enable its remote control by using mobile were made to electric-powered wheelchair in order to enable its remote control by mobile were made to an an electric-powered wheelchair in orderthe to wheelchair. enable itssystem remote control byto using using mobile software so that Smartphones and Tablets could control Details of the developed system, devices. Those modifications have focused on the wheelchair control and aimed emulate it in devices. Those modifications have focused on the wheelchair control system and aimed to it devices. Those modifications have focused on the wheelchair control system and aimed to emulate emulate it in in with emphasis on the telematics control will be given along the paper. software so that Smartphones and Tablets could control the wheelchair. Details of the developed system, software so that Smartphones and Tablets could control the wheelchair. Details of the developed system, software so that Smartphones and Tablets could control the wheelchair. Details of the developed system, with emphasis on the telematics control will be givenControl) along the paper.by Elsevier Ltd. All rights reserved. with emphasis on control be along © 2016, IFAC (International Federation Automatic Hosting Keywords: Tele-Medicine and e-Health, Intelligent andpaper. Ambient Intelligence, Ambient Assisted with emphasis on the the telematics telematics controlofwill will be given given Homes along the the paper. Living, Automatic Electric-Powered Wheelchair, Telematics Control and Monitoring. Keywords: Tele-Medicine and e-Health, Intelligent Homes and Ambient Intelligence, Ambient Ambient Assisted Assisted Keywords: Tele-Medicine and e-Health, Intelligent Homes and Ambient Intelligence, Keywords: Tele-Medicine and e-Health, Intelligent Homes Control and Ambient Intelligence, Ambient Assisted Living, Automatic Electric-Powered Wheelchair, Telematics and Monitoring. Living, Automatic Electric-Powered Wheelchair, Telematics Control and Monitoring. Living, Automatic Electric-Powered Wheelchair, Telematics Control and Monitoring. Ambient Intelligence (AmI) can be defined as an evolution 1. INTRODUCTION from the conventional automation systems, which Ambient (AmI) can be defined as an evolution Ambient Intelligence Intelligence (AmI) be defined as evolution 1. INTRODUCTION 1. (AmI) can can be the defined as an an ubiquitously and pervasively have purpose of evolution facilitate One of the most important assistive technology equipment Ambient from the theIntelligence conventional automation systems, which 1. INTRODUCTION INTRODUCTION from conventional automation systems, which the and conventional systems, which the execution of dailyautomation tasks [Remagnino2005] created to increase the mobility oftechnology people with motor from ubiquitously pervasively have the purpose of facilitate One of the most important assistive equipment ubiquitously and pervasively have the purpose of facilitate One of the most important assistive technology equipment ubiquitously and pervasively have the purpose of facilitate One of the most important assistive technology equipment [Romero2008]. These new systems hold a high degree of disabilities is the electric-powered wheelchair, (Electrical the execution of daily tasks [Remagnino2005] created to increase the mobility of people with motor the execution of daily tasks [Remagnino2005] created to increase the of people motor the execution of new daily tasks [Remagnino2005] created to or increase the mobility mobility ofwheelchair, people with with motor [Romero2008]. automation processes and products, and mix different Wheelchair EPW). Depending on the disabilities, potential These systems hold a high degree of disabilities is the electric-powered (Electrical [Romero2008]. These new systems hold aa high degree of disabilities is the electric-powered wheelchair, (Electrical [Romero2008]. These new systems hold high degree of disabilities is EPW). theamong electric-powered wheelchair, (Electrical technologies, which exist individually today, in an inhabited users may choose a large number of available models. automation processes and products, and mix different Wheelchair or Depending on the disabilities, potential automation processes and products, and mix different Wheelchair or EPW). Depending on the disabilities, potential automation processes and products, and mix different Wheelchair or EPW). Depending on the disabilities, potential integrated environment [Garate2005] [Harwing2002]. The In some cases, the useraa large is strong enough to command technologies, which exist individually today, in an inhabited users may choose among number of available models. technologies, which exist individually today, in inhabited users may choose among number of models. technologies, which exist[Garate2005] individually today, in an ancapable inhabited users may cases, choose among a large large number of available available models. final objective is to provide automatized systems of movement trough joysticks or similar devices, in extreme integrated environment [Harwing2002]. The In some the user is strong enough to command integrated environment [Garate2005] [Harwing2002]. The In some cases, the user is strong enough to command integrated environment [Garate2005] [Harwing2002]. The In some cases, the user isoruse strong enough to command providing comfort, entertainment, nursing elderly and ill cases it is necessary to make of solutions that consider final objective is to provide automatized systems capable of movement trough joysticks similar devices, in extreme final objective is automatized systems capable of movement trough or similar devices, in extreme final objective is to to provide provide automatized systems capable of movement troughto joysticks joysticks oruse similar devices, in consider extreme inhabitants, environment security, resource economy (energy, biological signal control the movement of the EPW. In all providing comfort, entertainment, nursing elderly and ill cases it is necessary to make of solutions that providing comfort, entertainment, nursing elderly and ill cases it is necessary to make use of solutions that consider providing comfort, entertainment, nursing elderly and ill cases it is necessary to make use of solutions that consider water), and other functionalities that will adapt to the need of cases it is assumed that a customization of the EPW is inhabitants, environment security, resource economy (energy, biological signal to control the movement of the EPW. In all inhabitants, environment security, resource economy (energy, biological signal to control the movement of the EPW. In all inhabitants, environment security, resource economy (energy, biological signal to control the movement of the EPW. In all the human being in these environments [Verhaegh2006] needed, normally it means, among other details, the selection water), and other functionalities that will adapt to the need of cases it is assumed that aa customization of EPW is water), and other functionalities that to cases it is assumed that customization of EPW is and[Sanchez2008]. other functionalities that will will adapt adapt to the the need need of of cases it normally is sensor assumed that aamong customization of the the EPW is water), [Litz2007] of the right for human-machine interfaces and custom the human being in these environments [Verhaegh2006] needed, it means, other details, the selection the human being in these environments [Verhaegh2006] needed, normally it means, among other details, the selection the human being in these environments [Verhaegh2006] needed, normally it means, among other details, the selection regulation driving parameters. [Sanchez2008]. of the rightofsensor for human-machine interfaces and custom [Litz2007] [Litz2007] [Sanchez2008]. of the for human-machine To implement the concept of Ambient Intelligence it's [Sanchez2008]. of the right rightofsensor sensor forparameters. human-machine interfaces interfaces and and custom custom [Litz2007] regulation driving regulation of driving parameters. necessary to involve a great of quantity of technologies and In fact, there are reports about how difficult it is to drive a To implement the concept Ambient Intelligence it's regulation of driving parameters. To implement the of Ambient Intelligence it's To implement the concept concept of Ambient Intelligence it's areas of knowledge related to electronics and software EPWs, many users faced many problems to learn how to necessary to involve a great quantity of technologies and In fact, there are reports about how difficult it is to drive a necessary to involve a great quantity of technologies and In fact, there are reports about how difficult it is to drive a necessary to involve a great quantity of technologies and In fact, there are reports about how difficult it is to drive a development [vanHouten2008]. These were first researched control them, users while faced othersmany just cannot useto them properly areas of knowledge related to electronics and software EPWs, many problems learn how to areas of knowledge related to electronics and software EPWs, many users faced many problems to learn how to areas ofPhilips knowledge related toThese electronics andinresearched software EPWs, many users faced many problems to them learnaffect how the to by the Company in their R&D labs Holland [Fehr2000] [Simpson2008]. Some other diseases development [vanHouten2008]. were first control them, while others just cannot use properly development [vanHouten2008]. These were first researched control them, while others just cannot use them properly development [vanHouten2008]. These were first researched control them, while others just cannot use them properly [Ist2001]. In order to obtain the desired characteristics of patients’ condition along time reducing their motor ability. In by the Philips Company in their R&D labs in Holland [Fehr2000] [Simpson2008]. Some other diseases affect the by the Philips Company in their R&D labs in Holland [Fehr2000] [Simpson2008]. Some other diseases affect the by the Philips Company in their R&D labs in Holland [Fehr2000] [Simpson2008]. Some other diseases affect the Ambient Intelligence the knowhow of technologies like new these cases the patients may lose their driving skills leading [Ist2001]. In order to obtain the desired characteristics of patients’ condition along time reducing their motor ability. In [Ist2001]. In order the characteristics of patients’ condition along time reducing their motor ability. In [Ist2001].Intelligence In micro-electromechanical order to totheobtain obtain the desired desired characteristics of patients’ condition along time reducing their motor ability. In Ambient materials, systems, sensor to a necessary change of the EPWs control interface. In any knowhow of technologies like new these cases the patients may lose their driving skills leading Ambient Intelligence the knowhow of technologies like new these cases the patients may lose their driving skills leading Ambient Intelligence the knowhow of technologies like new these cases the patients may lose their driving skills leading technology, wireless communication, adaptive software, cases, driving tests withof potential users are necessary. materials, micro-electromechanical systems, sensor to aa necessary change the EPWs control interface. In any materials, micro-electromechanical systems, sensor to change of the control interface. materials, systems, micro-electromechanical systems, sensor to a necessary necessary change ofpotential the EPWs EPWs control interface. In In any any technology, embedded software agents, and the like, are needed wireless communication, adaptive software, cases, driving tests with users are necessary. technology, wireless communication, adaptive software, cases, driving tests with potential users are necessary. That why, tests for awith long time from many academic technology, wireless communication, adaptive software, cases,isdriving potential users now, are necessary. [Mukherjee2006]. embedded systems, software agents, and the like, are needed embedded systems, studies addressed design of EPW driving simulators embedded systems, software software agents, agents, and and the the like, like, are are needed needed That is why, for aathelong time from now, many academic That is why, for long time from now, many academic [Mukherjee2006]. [Mukherjee2006]. That is addressed why,[Pithon2009]. for athelong time from now, many academic The current technological scene has allowed for even smaller [Erren2007] The first simulators made use of [Mukherjee2006]. studies design of EPW driving simulators studies addressed the design of EPW driving simulators studies addressed the design of EPW drivingmade simulators equipment have morescene processing and for communication 2D representations for driving electric-powered wheelchairs The current current to technological scene has allowed allowed for even smaller smaller [Erren2007] [Pithon2009]. The first simulators use of The technological has even [Erren2007] [Pithon2009]. The first simulators made use of The current technological scene has allowed for even smaller [Erren2007] [Pithon2009]. The first simulators made use of power, and with that new applications can be proposed. [Lefkowicz1992] [Swan1994]. Recently the simulators are equipment to to have have more more processing processing and and communication communication 2D representations for driving electric-powered wheelchairs equipment 2D representations for driving electric-powered wheelchairs equipment to have more processing and communication 2D representations for driving electric-powered wheelchairs Sensors actuators can be connected in wireless networks developed in 3D. Among the most successful tools, there are power, and with that new applications can be proposed. [Lefkowicz1992] [Swan1994]. Recently the simulators power, and with that new applications can be proposed. [Lefkowicz1992] [Swan1994]. Recently the simulators are and with thatcan applications can be amount proposed. [Lefkowicz1992] [Swan1994]. Recently the and simulators are power, with little cost, making itnew possible to obtain a great of the Wheelsim [Rnt2008, Lifetool2008] Accessim Sensors and actuators be connected in wireless networks developed in 3D. Among the most successful tools, there are Sensors and actuators can be connected in wireless networks developed in 3D. Among the most successful tools, there are Sensors and actuators can be connected in wireless networks developed in 3D. Among the most successful tools, there are data to a specific ambient or process, and act upon them [Ceremh2011]. with little cost, making it possible to obtain a great amount of the Wheelsim [Rnt2008, Lifetool2008] and Accessim with little cost, making it to aa great amount of the Wheelsim little cost, making it possible possible to obtain obtain great amount of the Wheelsim [Rnt2008, [Rnt2008, Lifetool2008] Lifetool2008] and and Accessim Accessim with data to a specific ambient or process, and act upon them [Ceremh2011]. data to a specific ambient or process, and act upon them [Ceremh2011]. data to a specific ambient or process, and act upon them [Ceremh2011]. Copyright © 2016 IFAC 181 2405-8963 © 2016, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved. Copyright 2016 IFAC 181 Peer review© of International Federation of Automatic Copyright ©under 2016 responsibility IFAC 181Control. Copyright © 2016 IFAC 181 10.1016/j.ifacol.2016.11.164
2016 IFAC TA 182 November 6-9, 2016. Porto Alegre, BrazilVictor L. Valenzuela et al. / IFAC-PapersOnLine 49-30 (2016) 181–185
[Pauwels2007]. And all of this should occur without direct user intervention.
signals of the mechanical joystick; or add another node to the internal CAN bus. The first option requires a digital-toanalog converter to generate two voltage levels, which represent the displacement of the joystick on the X and Y axes. The signals connect to the analog-to-digital converter of the I-MCU to replicate the behavior of the joystick. The second options requires CAN bus interface to send commands to the P-MCU directly, instead of going through the I-MCU, and must use the same definition of messages as the P-MCU and I-MCU.
However, in order for an Ambient Intelligence scenario to become reality, only data collection is not enough. It's necessary to imbue the system with computational intelligence so it can process data on its own in order to infer in the context of them and still take into consideration the perspective of the human user [Becker2006]. With that it's possible to make the ambient reactive and adaptable to the needs of the users.
Beyond the Wi-Fi connection, both approaches require additional hardware from the remote control microcontroller (RC-MCU): a CAN controller, which may be internal or external, and an external CAN transceiver, or a digital-toanalog converter, which may also be internal or external. Fig. 2 provides an overview of the whole system and how each device connects to the other.
Fig. 1. Basic Architecture of the CRIAI Project. Fig. 2. Overview of devices that compose the system.
The CRIAI project is inserted in this context, which is a joint research initiative focused on the proposal of an AmI system designed to help people with disabilities. Fig. 1 contains the main components of this project. Sensors and actuators were properly distributed in a set of rooms. They are controlled by a residential automation system that is also properly connected to the consumer electronic devices. Central point is an EPW that was modified to receive commands via BCI or other mobile devices. That is a very important point in the proposed architecture as it is desired that the EPW navigate autonomously in a known ambient.
2.1 Joystick Emulation The joystick emulation approach requires three steps to correctly connect the signals to the I-MCU and allow the RCMCU to replace the joystick: identify the voltage levels generated by the joystick, design the connection between DAC and ADC, and define the equation that converts the joystick displacement to the value range of the DAC. The working principle of the joystick is shown in Fig. 3. The joystick can assume any position inside the circle formed by its mechanism. The voltage level of the outputs varies based on the position that is currently being held.
The main objective of this paper is to describe the modifications made to the electric wheelchair during the CRIAI Project. The sole purpose of these changes was to enable remote control of the wheelchair by using mobile devices. The modifications have focused on the control system and aimed to emulate it in software so that Smartphones and Tablets could control the wheelchair. 2. CONTROL APPROACHES The commercial EPW used in this work has two microcontrollers inside it: the interface microcontroller (I-MCU), which manages the buttons, the joystick and the LEDs that allow the user to interact with the EPW; and the power microcontroller (P-MCU), which has control of the motors and brakes, manages the battery and stores a few setup parameters. The two MCUs communicate with each other through CAN bus.
Fig. 3. Working principle of the joystick. After measuring the voltage level at the joystick output, the values shown in table 1 were acquired for both X and Y axes.
At a first glance, there are two different approaches to add another device to control the EPW: emulate the electrical 182
2016 IFAC TA November 6-9, 2016. Porto Alegre, BrazilVictor L. Valenzuela et al. / IFAC-PapersOnLine 49-30 (2016) 181–185
183
Table 1: The voltage levels for both X and Y axes. X axis
Y axis
Center value
2.3V
Center value
2.3V
Left
3.3V
Forward
2.3V
Right
1.37V
Backwards
1.37V
Ref. value
2.45V
In order to evaluate both approaches, the UDOO single-board computer was selected because it features a microcontroller and a microprocessor that fulfil the requirements defined at the beginning of section 2. The Atmel SAM3X8E has both a digital-to-analog converter and a CAN controller in the same die, but it does not have Wi-Fi transceiver, nor support for a full-featured Internet Protocol stack. However, the Freescale MCIMX6Q runs the Linux OS which then provides the means to remotely control the EPW via Wi-Fi. Thus, the RCMCU is composed of two devices mentioned above.
Fig. 5. Application interface and working principle to generate intensity values. The movement commands are generated with its respective intensity, as was done by the joystick, and the result is an array that contains the displacement in both X and Y axes. As previously mentioned, the X axis represents left and right and the Y axis represents forward and backward, therefore, to distinguish the directions on each axis, the intensity is represented by an integer number from -100 to 100. A positive number is interpreted as “left” on the X axis and “forward” on the Y axis, whereas a negative number is interpreted as the opposite direction for each axis. The table 2 shows how an array is composed, where Xi and Yi are the desired intensity value for that axis. As an example, the array X;50;Y;50 results in 50% intensity to the left and 50% intensity forward, whereas the array X;0;Y;-100 results in no X axis movement and 100% backwards.
The signal conditioning had to be developed around the voltage range provided by the DAC of the SAM3X8E, which is from 0.5V, at its lowest, to 2.8V, at its highest. Since the joystick operates inside the 1.3V to 3.3V range, a noninverting gain circuit was used, as shown in Fig. 4. The output of this circuit if given by the following formula: Vout = 1.2×Vin. The joystick also generated a voltage reference value as a mechanism to detect if it was working properly, as shown in table 1.
Table 2: The format of the data array received from the joystick application.
The connection of the DAC and ADC is done as follow: DAC0 and DAC1 connect to the pins of the same name on the SAM3X8E of the RC-MCU, which are the pins 66 and 67 on the UDOO; and JOY_X, JOY_Y, and JOY_VREF are connected to the pins that lead to the ADC of the I-MCU on the EPW.
byte
byte
byte
byte
byte
byte
byte
0
1
2
3
4
5
6
X
‘;’
Xi
‘;’
Y
‘;’
Yi
On the i.MX6Q of the RC-MCU, the software is responsible for receiving the data array from the remote application and converting the parameters to the values used by the SAM3X8E of the RC-MCU. This process is required because the DAC uses 8-bit values, i.e., to generate 2.8V, the 8-bit value input is 255, and to generate 0.5V, the 8-bit value input is 0. Thus, to emulate the range of the joystick, the 8-bit values shown in table 3 were used. Table 3: Voltage levels and their respective 8-bit values.
Fig. 4. Signal conditioning circuit. As mentioned at the beginning of this work, all movement commands are issued by an application running on a Smartphone or a Tablet and its interface is shown in Fig. 5. The communication between the application and the software running on the i.MX6Q of the RC-MCU is performed via TCP socket. 183
Position
Voltage
8-bit value
Center value
2.3V
152 (0x98)
Left/Forward
3.3V
250 (0xFA)
Right/Backwards
1.37V
58 (0x3E)
2016 IFAC TA 184 November 6-9, 2016. Porto Alegre, BrazilVictor L. Valenzuela et al. / IFAC-PapersOnLine 49-30 (2016) 181–185
Based on these values, the equation (1) was determined in order to convert the intensity values from -100 to 100 into the 8-bit values required by the DAC. Then, using the equation, the software running on the i.MX6Q uses the same array structure shown in table 2 to send to the SAM3X8E the data array with Xi and Yi replaced by the calculated 8-bit values. Using the same previous examples, the array X;50;Y;50 results in 199 for both X and Y axes, thus the new array is X;199;Y;199, whereas the array X;0;Y;-100 results in 152 for the X axis and 58 for the Y axis, thus the new array is X;152;Y;58.
Because the UDOO board has been deployed to this system, two options were designed to attach the RC-MCU to the CAN bus. As shown in Fig. 7, the CAN node can be managed by the i.MX6Q or by the SAM3X8E. The first option uses the SPI port to control an external CAN controller, the MCP2515, and uses the SN65HVD234D CAN transceiver. The second option uses the same external transceiver, but, instead of the MCP2515, it uses the internal CAN controller of the SAM3X8E. The test circuit is shown in Fig. 8.
(1)
Fig. 6. Diagram overview of the joystick emulation approach.
Fig. 7. Diagram overview of the network node inclusion approach.
In summary, for the first approach, in which the joystick is emulated, the system shown in Fig. 6 was achieved. This control solution was put under test to determine its performance and a few points have been noted:
The number of TCP hops in the Wi-Fi network interferes with operation of the EPW. If this number is too high and the network has high traffic, packages are either lost or delayed and real-time maneuvering is compromised.
The responsiveness is slightly minor than the stock, mechanical joystick and maneuvering the EPW at high speeds causes more crashes, but at lower speeds the difference in responsiveness is barely noticeable.
Manual operation is not possible because the emulated joystick uses the same ADC channels of the joystick. For safety purposes, both methods should be able to operate in parallel, which would require 4 ADC channels, but that is not available as default by the manufacturer.
Fig. 8. CAN controller and transceiver circuit.
2.1 Network node inclusion
Though this method was not fully tested, some assumptions can be made about its performance and features.
The network node inclusion approach also requires three steps to correctly connect the RC-MCU to the internal CAN bus of the EPW: map the message frames exchanged between P-MCU and I-MCU during normal operation, design the connection to the CAN bus, and define a procedure to convert the movement commands into the message frames used by both I-MCU and P-MCU. Most information regarding the method of communication, only the CAN bus connection was proposed and not entirely tested.
184
This control method is more expensive and more invasive, because it requires more components to be built and knowledge about the proprietary method of communication between P-MCU and I-MCU.
The responsiveness is similar to the joystick emulation method, because this issue is mainly caused by the WiFi network communication.
2016 IFAC TA November 6-9, 2016. Porto Alegre, BrazilVictor L. Valenzuela et al. / IFAC-PapersOnLine 49-30 (2016) 181–185
185
Harwig, R., and Aarts, E. (2002). Ambient Intelligence: invisible electronics emerging. Proc. of the IEEE Int. Conf. on Interconnect Technology, 2002.; pp. 3 – 5. IST Advisory Group (ISTAG) (2001). Ambient Intelligence: From Vision to Reality, European Commission, 2001. Lefkowicz, A.T. (1993). Validation of a PC-based perspective-view wheelchair simulator. Virginia Polytechnic Institute and State University. Lifetool Solutions. (2008). Lifetool: Wheelsim. In: http://www.lifetool-solutions.at/de/. Litz, L., and Gross, M. (2007). Covering Assisted Living Key Areas based on Home Automation Sensors; IEEE Int. Conf. on Networking, Sensing and Control, 15-17 April 2007, pp. 639 – 643. Mukherjee, S., Aarts, E., Roovers, R., Widdershoven, F., and Ouwerkerk, M. (2006). AmIware Hardware Technology Drivers of Ambient Intelligence, Philips Research Book Series, Springer, 480 p., 2006. Pauwels, E.J., Salah, A.A., and Tavenard, R. (2007). Sensor Networks for Ambient Intelligence, IEEE 9th Workshop on Multimedia Signal Processing MMSP 2007, 1-3 Oct. 2007, pp. 13 – 16. Pithon, T., Weiss, T., Richir, S., and Klinger, E. (2009). Wheelchairs simulators: a review. Technology and Disability, volume 21, pp. 1-10. Remagnino, P., and Foresti, G.L. (2005). Ambient Intelligence: A New Multidisciplinary Paradigm; IEEE Transactions on Systems, Man and Cybernetics, Part A, Vol. 35, Issue 1, pp. 1 – 6, Jan. 2005 RNT Association of Paralyse France. (2008). Wheelsim: a play of simulation of control in electric wheel chair. In: http://rnt.over-blog.com/article-21608792.html. Romero, M., Pousman, Z., amd Mateas, M. (2008) Alien presence in the home: the design of Tableau Machine; ACM Personal and Ubiquitous Computing; Vol. 12, Issue 5, June 2008, pp. 373 - 382. Sanchez, D., Tentori, M., and Favela, J. (2008). Activity Recognition for the Smart Hospital; IEEE Intelligent Systems, Vol. 23, Issue 2, March-April 2008 pp. 50 – 57. Simpson, R., Lopresti, E., and Cooper, R. (2008). How many people would benefit from a smart wheelchair. Journal of Rehabilitation Research and Development, vol. 45(1), pp. 53-72. Swan Li, J.E., Stredney, D., Carlson, W., and Blostein, B. (1994). The determination of wheelchair user proficiency and environmental accessibility through virtual simulation. Proc. of the 2nd Annual Int. Conf. Virtual Reality and Persons with Disabilities, page 156-161. van Houten, H. (2005) The physical layer of ambient intelligence, Int. Symp. on VLSI Technology, pp. 9 – 12. Verhaegh, W., Aarts, E., and Korst, J. (2006). Intelligent Algorithms in Ambient and Biomedical Computing, Philips Research Book Series, Springer, 320 p., 2006.
Manual operation is possible because the I-MCU and RC-MCU are independent and can simultaneously send commands to the P-MCU. Though the impact of simultaneous control was not tested. 3. CONCLUSION AND FUTURE WORK
Both control methods have its advantages and disadvantages, which are mainly cost, simplicity and safety. Given that the second approach was not fully tested, it is not possible to claim which of the two has better performance. However, at this stage, this remote control method helps nurses to take care of people with disabilities who are not able to drive themselves with the EPW, as they will not be required to push and maneuver it around. Moreover, the results of this work are the basis of two larger research projects. The first project is the CRIAI project, which was mentioned earlier. The second project uses the remotely-controlled EPW of this work in a safe environment for remote training and assessment of EPW driving skills, which will assist the rehabilitation of new wheelchair users. Finally, in order to improve the comfort of those being transported or those taking care, cameras may be added to the EPW to provide autonomous navigation and certified safety laser scanners may also be added to avoid collisions. ACKNOWLEDGEMENTS The authors would like to thank the Funding Authority for Studies and Projects (FINEP) Organization and the Environmental and Technological Institute of the Amazon (IATECAM) for the financial support, the Research and Development of Information and Electronics Technology Center (CETELI) for providing the infrastructure of laboratories and tools. REFERENCES Becker, M., Werkman, E., Anastasopoulos, M., and Kleinberger, T. (2006). Approaching Ambient Intelligent Home Care Systems; Pervasive Health Conference and Workshops, pp. 1 – 10; 2006. Ceremh - Center of Resources and Innovation Mobility and Handicap (CEREMH). (2011). The accessim project. In: http://www.ceremh.org/accessibilite/recherche-andinnovation-47/accessim/. Erren-Wolters et al. (2007). Virtual reality for mobility devices: training applications and clinical results: a review. International Journal of Rehabilitation Research, vol. 30, page 91-96. Fehr, L., Langbein, W., and Skaar, S. (2000). Adequacy of power wheelchair control interface for persons with severe disabilities: a clinical survey. Journal of Rehabilitation Research and Development, vol. 37(3). Garate, A., Lucas, I., Herrasti, N., and Lopez, A. (2005) Ambient intelligence as paradigm of a full automation process at home in a real application. Proc. of IEEE Int. Symposium on Computational Intelligence in Robotics and Automation, 2005. CIRA 2005., pp. 475 – 479.
185