- Email: [email protected]
Development of an autonomous mobile plant irrigation robot for semi structured environment
Available online at www.sciencedirect.com
ScienceDirect
Available online at www.sciencedirect.com Available online at www.sciencedirect.com Procedia Manufacturing 00 (2019) 000–000
ScienceDirect ScienceDirect
Procedia Manufacturing 00 (2019) 000–000 Procedia Manufacturing 35 (2019) 9–15
www.elsevier.com/locate/procedia
www.elsevier.com/locate/procedia
2nd International Conference on Sustainable Materials Processing and Manufacturing (SMPM 2019) 2nd International Conference on Sustainable Materials Processing and Manufacturing
Development of an autonomous (SMPMmobile 2019) plant irrigation robot for semi structured environment a Development of an plant irrigation forCa Adeodu A. O*a, Bodunde O. autonomous Pb, Daniyan I. Ac.,mobile J. Orobot ., Adie U. Omitola O. Od., Akinyoola semi structured environment Department of Mechanical and Mechatronics Engineering Afe Babalola University, Ado-Ekiti, Nigeria a
c a b Adeodu A. O*aof, Bodunde O.Automation Pb, Daniyan I. Athe .,Chinese Omitola O. OofdHong ., Akinyoola J.N.OT., .,HKSAR Adie U. Ca Department Mechanical and Engineering, University Kong, Sha Tin,
c Department of Industrial Engineering, Tshwane University of Technology, Pretoria, South Africa of Electrical, Electronic and Computer Engineering, Afe Babalola University, Ado-Ekiti, Nigeria Department a Department of Mechanical and Mechatronics Engineering Afe Babalola University, Ado-Ekiti, Nigeria b Department of Mechanical and Automation Engineering, the Chinese University of Hong Kong, Sha Tin, N. T., HKSAR c Department of Industrial Engineering, Tshwane University of Technology, Pretoria, South Africa d Abstract Department of Electrical, Electronic and Computer Engineering, Afe Babalola University, Ado-Ekiti, Nigeria d
The aim of this research is to develop an autonomous mobile plant irrigation robot. The system uses an Xbee Series 1wireless communication to communicate between the mobile robot and a moisture sensing module which is fully adaptive to a semiAbstract structured environment taking into account the watering needs of the plants. Other components are microcontroller, an on-board water reservoir an attached water pump. The performance evaluation of the autonomous irrigation based on the The aim of this and research is to develop an autonomous mobile plant irrigation robot. The system uses anrobot Xbeewas Series 1wireless analysis of the water carrying capacity, of watering peracycle, and sensing time requirements to water a given area to of aland. It communication to communicate betweendistance the mobile robot and moisture module which is fully adaptive semishows thatenvironment 5 litres of water caninto be maintained 150 seconds bythe theplants. robot. Other The soil moisture data at different timesanofon-board the day structured taking account the for watering needs of components are microcontroller, during the day lower thanevaluation after irrigation carried out. The efficiency of the irrigation deduced that theand moisture contentwater water reservoir an attached pump. Thewas performance of thewas autonomous irrigation robot was based on the robot wasofalso by the relationship between volumeper of water andrequirements the speed oftothe mobile robot.area It shows that analysis the examined water carrying capacity, distance of watering cycle, carried and time water a given of land. It 0.38 Nthat torque would permitcan thebe movement of for the 150 robotseconds by 1 mbyatthe a water lessatordifferent equal totimes 3. 5 of litres. shows 5 litres of water maintained robot.carrying The soilcapacity moistureofdata the The day autonomous irrigation robot during system the constructed based than on ZigBee overcomes limitations of the fixed sprinkler system deduced that plant the moisture content day was lower after irrigation wasthe carried out. The efficiency of the irrigation and largeexamined space consumption. robotavoids was also by the relationship between volume of water carried and the speed of the mobile robot. It shows that Keywords: Autonomous; Irrigation; content; Mobile communication 0.38 N torque would permit theMoisture movement of the robotRobot; by 1 Wireless m at a water carrying capacity of less or equal to 3. 5 litres. The © 2019 The Authors. Published by Elsevier B.V. autonomous plant irrigation robot system constructed based on ZigBee overcomes the limitations of the fixed sprinkler system Peer-review under responsibility of the organizing committee of SMPM 2019. and avoids large space consumption. Keywords: Autonomous; Irrigation; Moisture content; Mobile Robot; Wireless communication 1. Introduction
Plants are known to add ecstatic value to natural environment apart from means of soil conservation [1]. A study 1. Introduction conducted by NASA and ALCA [2] shows that species of some beautifying plants not only make normal environment attractive, but also assist in the purification of the inhaled air by absorbing toxins and also perform Plantsfunction are known to add ecstatic value to environment apart from means soil conservation [1]. stress A study little of oxygen dissemination to natural the environment. Plant have also been of discovered to alleviate by conducted by NASA and ALCA [2] shows that species of some beautifying plants not only make normal easing mental fatigue improving quality of air. Therefore, plants are indispensable part of human life [1]. environment attractive, but also assist in the purification of the inhaled air by absorbing toxins and also perform little function of oxygen dissemination to the environment. Plant have also been discovered to alleviate stress by easing mental fatigue and improving quality of air. Therefore, plants are indispensable part of human life [1]. 2351-9789 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the organizing committee of SMPM 2019. *Corresponding Author: 2351-9789 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the organizing committee of SMPM 2019. Email: [email protected] *Corresponding Author: Email: [email protected] 2351-9789 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the organizing committee of SMPM 2019. 10.1016/j.promfg.2019.05.004
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Adeodu, A.O et al./ Procedia Manufacturing 00 (2019) 000–000 A.O. Adeodu et al. / Procedia Manufacturing 35 (2019) 9–15
Unfortunately, many plants wither off due to insufficient watering. This can be labour intensive and stressful coupled with the usual activities of the operator. Thus, maybe easily ignored by the owner [1]. Applying modern techniques of watering, the cumbersomeness and ergonomic disadvantage of the operator are major challenges aside the cost ineffectiveness. Thus, the autonomous mobile robot may proffer effective solution to the menace [1]. Examining various researches by different authors on the modern techniques of plant watering systems, one could easily point to the areas where contributions are needed. A work by Kevin Sikorski [3] was developed as part of Intel Research known as A Robotic Plant Care System. This system uses laser range finder to locate pot plants in the lab environment and carry out the watering action. The limitation of the work, aside the cost ineffectiveness is the imperfection of integration of the system to the wireless network of Intel Research Lab where the laser finder fails sometimes due to environmental constraints. A Pot-Pet flowering robot was also done by Kawakami et al. [4]. The system was design in such that plants are autonomously mobile using chair robotic structure equip with wheels. The limitation of the Pot-Pet is that it still been watered manually by stand by operator thus making it partly autonomous and the menace caused by moving around of the pot. According to Angelopoulos at al. [5], a smart system for garden watering using wireless sensor network was developed. The soil moisture content was analysed using sensor. The system has a defect of not been portable. The valves are attached to the rotted plant, thus truncating the growth of the plant. Sadeky et al. [6] also applied acoustic based mechanism to measure soil moisture in real time method. The technique was based on relationship between speed of sound and the degree of saturation in the soil. The analysis of the design shows that speed of sound decreases as moisture content decreases. The limitation of the work was inability to factor into the design the types of soil. With the literature reviews presented, the research aimed at development of an autonomous mobile plant irrigation robot for a semi structured environment been able to avoid obstacle on its way. The robot design integrate humidity sensor module with an infrared sensor for moisture detecting and obstacle avoidance respectively through an interface of Arduino-Xbee board. The motion of the robot is constraint to only forward motion command. The study is limited for field experiment. 2.1 System Architecture and Description The plant irrigation mobile robot is designed to be able to water a given area of land without human intervention. The robot action is divided into two major phases, which are moisture sensing phase and irrigation phase, implemented by two different modules. The moisture sensing action is achieved using the YL-69 soil sensor, controlled using ATmega328 microcontroller based on arduino platform. The irrigation and mobility of the robot are controlled by DC motors and water pump relay integrated to another Arduino microcontroller to carry out watering action depending on the soil moisture data. The robot’s activity can be divided into two which are plant watering and the robot’s movement activities. The plant watering is shown by the block diagram in figure 1. Figures 2 and 3 show the circuit diagrams of the transmitter and receiver modules. Module 1: Comprises of Zigbee Xbee module (configured as a transmitter), Arduino Uno microcontroller and moisture sensor placed on the area of land to be monitored, LCD and power supply. Module 2: Comprises of Zigbee Xbee module (configured as a receiver), chassis, water tank, a second Arduino Uno microcontroller, DC water pump, IR sensor module. The robot movement stage uses a line following algorithm with the aid of 2 infrared sensor modules. The robot is able to maneuver across a path using a single black line on a white surface. This enables the robot move through the plant spacing on the farmland during sprinkling. The system can carry only a limited amount of water in one go due to it limited water carrying capacity and the weight the DC motors attached. This also restricts the size of the working area. Since a DC power is supplied to the water pump, the configuration of water pump is taken to be 12V or less. The water pump is triggered using a 6V relay which acts like a switch to toggle it instead of physical touching. For a relay to trigger, an external 9-volt power supply is required.
Adeodu, A.O et al./ Procedia Manufacturing 00 (2019) 000–000 A.O. Adeodu et al. / Procedia Manufacturing 35 (2019) 9–15
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The moisture sensor module is mounted close to the soil so as to easily detect the level of humidity of the soil.
Figure 1: Block Diagram of the System
2.2 System Design The transmitter and receiver circuits were initially designed and tested on a solderless breadboard considering all the components involved and power supply before soldering on a veroboard. 2.2.1 Circuit Design of the Transmitter Module The following components were used in designing the transmitter module i. YL-69 Soil Moisture Sensor: YL-69 soil moisture sensor is placed in the soil where the plants to be watered are located to sense the moisture content values of the soil and analyze its watering needs accordingly. It comprises of a two legged Lead, that goes into the soil or anywhere else where water content has to be measured. It has two header pins which connect to an Amplifier/ A-D circuit which is in turn connected to the Arduino. ii. 1602 Liquid Crystal Display (LCD): The LCD gives real-time information of the moisture content of the soil at a remote location from the irrigation robot (receiver module). It is interfaced with an I2C module to simplify the connections to the arduino. The module converts the 16 pin interface on the LCD into 4 pins. iii. Xbee (Series 1) Module (Transmitter Configuration) Xbee is the wireless communication device used to transmit moisture content data of the soil to the mobile robot wirelessly. It covers a linear range of about 300 ft (~100m). iv. Power Supply Power supply to the transmitter module is achieved using a 9 V battery connected to the power port of the arduino. Other components derive their power form the arduino. 2.2.2 Circuit Design of the Receiver Module The following components were used in designing the receiver module i. L293D and DC motors Two 12 V geared motors were used to drive the irrigation robot. They were controlled by a single L293D IC. ii. Design of Motor Expected volume of water to be carried in one cycle, 𝑉𝑉w = 3 𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 =3.00×10−3 𝑚𝑚3 Mass of water, mw = 𝜌𝜌𝜌𝜌=1000× 3.0×10−3 = 3.00 𝑘𝑘𝑘𝑘 Approximate mass of robot (wheels + water + pump + electronics) = 4.0 𝑘𝑘𝑘𝑘
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Adeodu, A.O et al./ Procedia Manufacturing 00 (2019) 000–000 A.O. Adeodu et al. / Procedia Manufacturing 35 (2019) 9–15
Estimated total mass = 4.5 kg Required theoretical velocity of robot, 𝑣𝑣 = 0.3 𝑚𝑚/𝑠𝑠 Required acceleration of robot = 𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟 𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣/𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡 = 0.3/3= 0.1 𝑚𝑚/𝑠𝑠2 Total force required to drive total robot mass = 4.5 × 0.1= 0.45 𝑁𝑁 Robot would use 2 primary motors for movement, Therefore, each motor only needs to supply 1/2 × 0.45 = 0.225 𝑁𝑁 Measured wheel diameter = 0.0865 𝑚𝑚 Minimum theoretical torque required from each wheel = 𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡 𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓 × 𝑑𝑑𝑑𝑑𝑑𝑑𝑡𝑡𝑎𝑎𝑎𝑎𝑎𝑎𝑒𝑒 (𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑) = 0.225× 0.0865 = 0.0195 kgm =𝟎𝟎.𝟏𝟏𝟏𝟏𝟏𝟏 𝐍𝐍𝐍𝐍
iii. IR Sensor This IR sensor utilizes a TCRT5000 to detect colour and distance. Two of said sensor were used to detect obstacles during the motion of the mobile robot.
iv. Relay and Water Pump The Arduino Uno is not able to control the 12 V pump directly due to the voltage and current drawn by the pump, however, a 12 V single channel relay module (SPDT) was used for switching the pump to control its ON and OFF states. v. Design of Pump Maximum flow rate of pump, 𝑄𝑄max =240 𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 𝑝𝑝𝑝𝑝𝑝𝑝 ℎ𝑜𝑜𝑜𝑜𝑜𝑜 = 6.67× 10−5 𝑚𝑚3/𝑠𝑠 Time taken before water is exhausted during sprinkling, 𝑡𝑡 = 𝑉𝑉w/𝑄𝑄max = 22.49 𝑠𝑠 Distance of sprinkling for 1 cycle, 𝑆𝑆 = 𝑣𝑣 × 𝑡𝑡 = 0.3×22.49 = 6.75 𝑚𝑚 , as shown in Figure 2 From plant spacing, total distance of sprinkling from A to B The extra 0.25m is left to account for over-sprinkling, since efficiency is not always 100% . Since distance of sprinkling for 1 cycle is greater than total distance of sprinkling, the robot will not run out of water. vi. Xbee (Series 1) Module (Receiver Configuration) The connection of the Xbee acting as a receiver is similar to the precious configuration in the transmitter module with the only difference being the Tx pin on the Xbee was connected to Rx pin on the arduino Uno. 3.0 Performance Evaluation The test was done on a flat, smooth farmland with plant spacing and maximum slope angle of 1.0 m x 0.5 m and 2o, respectively during the plant growing season. The system layout configuration is shown in Figure 2 it indicates robot path and range of sprinkling.
Figure 2: System Layout Configuration
Adeodu, A.O et al./ Procedia Manufacturing 00 (2019) 000–000 A.O. Adeodu et al. / Procedia Manufacturing 35 (2019) 9–15
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3.1 Relationship between Volume of Water used during Sprinkling and Time Figure 3 shows variation of the amount of water consumed (in litres) with time during a sprinkling cycle. Considering that the robot’s tank capacity from the graph, it can be deduced based on flow rate of the pump, that the water would be exhausted above 100 seconds. So a complete sprinkling cycle would last for about 2:30 minutes.
Figure 3: Graph of Volume of Water against Time
3.2
Soil Moisture Data at Different Times of the Day
From Figure 4, it can be deduced that the moisture content during evening is lower than morning when irrigation has been carried out. The blue curve indicates high moisture content. The red curve indicates low moisture content during evening hours after irrigation has been carried out by the robot in the morning. Distribution was carried out over a period of 7 days as shown in Table 1. Table 1. Variation of Moisture Content against Time day
morning
evening
1
810
387
2
955
344
3
754
404
4
709
290
5
880
323
6
732
461
7
910
308
614
Adeodu, A.O. A.O et al./ Procedia 00 (2019) 35 000–000 Adeodu et al. / Manufacturing Procedia Manufacturing (2019) 9–15
Figure 4: Graph of Moisture Content against Time
3.3 Relationship between Volume of Water Carried and Speed of the Mobile Robot From the motor calculations in section 2, minimum theoretical torque required from each wheel is 𝟎𝟎.𝟏𝟏𝟏𝟏𝟏𝟏 𝑵𝑵𝑵𝑵. Therefore, 2 driver wheels produce a total torque of 0.382 𝑁𝑁𝑁𝑁 (38.2 𝑁𝑁𝑁𝑁𝑁𝑁) meaning the robot is able to move ≈38 𝑁𝑁 in 1 𝑐𝑐𝑐𝑐. No load velocity of robot is approximately 0.8 𝑚𝑚/𝑠𝑠 from testing and is shown in Table 2. When carrying capacity of the tank exceeds 3.5 𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 (3.5×10−3𝑚𝑚) = 34.335𝑁𝑁, the robot would not be able to move and the motors would be stalled as shown in Figure 5. Table 2. Speed Variation with Water Volume of Tank S/N Volume Speed (m/s) (liters) 1 0 0.8 2
0.5
0.5
3
1
0.4
4
1.5
0.2
5
2
0.09
6
2.5
0.06
7
3
0.01
8
3.5
0.005
9
4
0
10
4.5
0
Figure 5 Graph of Speed Variation with Volume
Adeodu, A.O et al./ Procedia Manufacturing 00 (2019) 000–000 A.O. Adeodu et al. / Procedia Manufacturing 35 (2019) 9–15
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4.0 Conclusion The wireless plant irrigation robot system constructed based on ZigBee overcomes the limitations of the fixed sprinkler system and avoids large space consumption. The system performance shows that it’s efficient and cost effective. 4.1 Recommendations The following improvements can be made to the project to increase efficiency and accessibility. i. The use of solar panels and rechargeable batteries to make the system efficient, reliable, and selfsustainable. ii. Incorporate the remote system management via Android smart-phones using the internet iii. Plant detection and obstacle avoidance can be improved via a wireless web camera and ultrasonic sensors, respectively. References [1] N. Hema, A. Reema, and M. Monisha. “Plant Watering Autonomous Mobile Robot”. International Journal of Robotics and Automation. Vol. 1(3), 2012, pp 152-162 [2] B. C. Wolverton, A. Johnson, and K. Bounds, “Interior Landscape Plants for Indoor Air Pollution Abatement: Final Report”, National Aeronautics and Space Administration (NASA-TM-101768) Science and Technology Laboratory, Stennis Space Center, 1989. [3] K. Sikorski, “A Robotic Plant Care System”, A Thesis, University of Washington, Intel Research, 2003. [4] A. Kawakami, K. Tsukada, K. Kambara and I. Siio, “PotPet: Pet-like Flowerpot Robot”, Tangible and Embedded Interaction, ACM New York, NY, USA, 2011, Pages 263-264. [5] C. M. Angelopoulos, S. Nikoletseas, G. C. Theofanopoulos, “A Smart System for Garden Watering using Wireless Sensor Networks”, MobiWac 11, Proceedings of the 9th ACM International Symposium on Mobility Management and Wireless Access, New York, NY, USA, 2011, Pages 167-170. [6] S. Sadeky, A. Al-Hamadiy, B. Michaelisy, and U. Sayedz”, An Acoustic Method for Soil Moisture Measurement”, IEEE 2004
ScienceDirect
Available online at www.sciencedirect.com Available online at www.sciencedirect.com Procedia Manufacturing 00 (2019) 000–000
ScienceDirect ScienceDirect
Procedia Manufacturing 00 (2019) 000–000 Procedia Manufacturing 35 (2019) 9–15
www.elsevier.com/locate/procedia
www.elsevier.com/locate/procedia
2nd International Conference on Sustainable Materials Processing and Manufacturing (SMPM 2019) 2nd International Conference on Sustainable Materials Processing and Manufacturing
Development of an autonomous (SMPMmobile 2019) plant irrigation robot for semi structured environment a Development of an plant irrigation forCa Adeodu A. O*a, Bodunde O. autonomous Pb, Daniyan I. Ac.,mobile J. Orobot ., Adie U. Omitola O. Od., Akinyoola semi structured environment Department of Mechanical and Mechatronics Engineering Afe Babalola University, Ado-Ekiti, Nigeria a
c a b Adeodu A. O*aof, Bodunde O.Automation Pb, Daniyan I. Athe .,Chinese Omitola O. OofdHong ., Akinyoola J.N.OT., .,HKSAR Adie U. Ca Department Mechanical and Engineering, University Kong, Sha Tin,
c Department of Industrial Engineering, Tshwane University of Technology, Pretoria, South Africa of Electrical, Electronic and Computer Engineering, Afe Babalola University, Ado-Ekiti, Nigeria Department a Department of Mechanical and Mechatronics Engineering Afe Babalola University, Ado-Ekiti, Nigeria b Department of Mechanical and Automation Engineering, the Chinese University of Hong Kong, Sha Tin, N. T., HKSAR c Department of Industrial Engineering, Tshwane University of Technology, Pretoria, South Africa d Abstract Department of Electrical, Electronic and Computer Engineering, Afe Babalola University, Ado-Ekiti, Nigeria d
The aim of this research is to develop an autonomous mobile plant irrigation robot. The system uses an Xbee Series 1wireless communication to communicate between the mobile robot and a moisture sensing module which is fully adaptive to a semiAbstract structured environment taking into account the watering needs of the plants. Other components are microcontroller, an on-board water reservoir an attached water pump. The performance evaluation of the autonomous irrigation based on the The aim of this and research is to develop an autonomous mobile plant irrigation robot. The system uses anrobot Xbeewas Series 1wireless analysis of the water carrying capacity, of watering peracycle, and sensing time requirements to water a given area to of aland. It communication to communicate betweendistance the mobile robot and moisture module which is fully adaptive semishows thatenvironment 5 litres of water caninto be maintained 150 seconds bythe theplants. robot. Other The soil moisture data at different timesanofon-board the day structured taking account the for watering needs of components are microcontroller, during the day lower thanevaluation after irrigation carried out. The efficiency of the irrigation deduced that theand moisture contentwater water reservoir an attached pump. Thewas performance of thewas autonomous irrigation robot was based on the robot wasofalso by the relationship between volumeper of water andrequirements the speed oftothe mobile robot.area It shows that analysis the examined water carrying capacity, distance of watering cycle, carried and time water a given of land. It 0.38 Nthat torque would permitcan thebe movement of for the 150 robotseconds by 1 mbyatthe a water lessatordifferent equal totimes 3. 5 of litres. shows 5 litres of water maintained robot.carrying The soilcapacity moistureofdata the The day autonomous irrigation robot during system the constructed based than on ZigBee overcomes limitations of the fixed sprinkler system deduced that plant the moisture content day was lower after irrigation wasthe carried out. The efficiency of the irrigation and largeexamined space consumption. robotavoids was also by the relationship between volume of water carried and the speed of the mobile robot. It shows that Keywords: Autonomous; Irrigation; content; Mobile communication 0.38 N torque would permit theMoisture movement of the robotRobot; by 1 Wireless m at a water carrying capacity of less or equal to 3. 5 litres. The © 2019 The Authors. Published by Elsevier B.V. autonomous plant irrigation robot system constructed based on ZigBee overcomes the limitations of the fixed sprinkler system Peer-review under responsibility of the organizing committee of SMPM 2019. and avoids large space consumption. Keywords: Autonomous; Irrigation; Moisture content; Mobile Robot; Wireless communication 1. Introduction
Plants are known to add ecstatic value to natural environment apart from means of soil conservation [1]. A study 1. Introduction conducted by NASA and ALCA [2] shows that species of some beautifying plants not only make normal environment attractive, but also assist in the purification of the inhaled air by absorbing toxins and also perform Plantsfunction are known to add ecstatic value to environment apart from means soil conservation [1]. stress A study little of oxygen dissemination to natural the environment. Plant have also been of discovered to alleviate by conducted by NASA and ALCA [2] shows that species of some beautifying plants not only make normal easing mental fatigue improving quality of air. Therefore, plants are indispensable part of human life [1]. environment attractive, but also assist in the purification of the inhaled air by absorbing toxins and also perform little function of oxygen dissemination to the environment. Plant have also been discovered to alleviate stress by easing mental fatigue and improving quality of air. Therefore, plants are indispensable part of human life [1]. 2351-9789 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the organizing committee of SMPM 2019. *Corresponding Author: 2351-9789 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the organizing committee of SMPM 2019. Email: [email protected] *Corresponding Author: Email: [email protected] 2351-9789 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the organizing committee of SMPM 2019. 10.1016/j.promfg.2019.05.004
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Adeodu, A.O et al./ Procedia Manufacturing 00 (2019) 000–000 A.O. Adeodu et al. / Procedia Manufacturing 35 (2019) 9–15
Unfortunately, many plants wither off due to insufficient watering. This can be labour intensive and stressful coupled with the usual activities of the operator. Thus, maybe easily ignored by the owner [1]. Applying modern techniques of watering, the cumbersomeness and ergonomic disadvantage of the operator are major challenges aside the cost ineffectiveness. Thus, the autonomous mobile robot may proffer effective solution to the menace [1]. Examining various researches by different authors on the modern techniques of plant watering systems, one could easily point to the areas where contributions are needed. A work by Kevin Sikorski [3] was developed as part of Intel Research known as A Robotic Plant Care System. This system uses laser range finder to locate pot plants in the lab environment and carry out the watering action. The limitation of the work, aside the cost ineffectiveness is the imperfection of integration of the system to the wireless network of Intel Research Lab where the laser finder fails sometimes due to environmental constraints. A Pot-Pet flowering robot was also done by Kawakami et al. [4]. The system was design in such that plants are autonomously mobile using chair robotic structure equip with wheels. The limitation of the Pot-Pet is that it still been watered manually by stand by operator thus making it partly autonomous and the menace caused by moving around of the pot. According to Angelopoulos at al. [5], a smart system for garden watering using wireless sensor network was developed. The soil moisture content was analysed using sensor. The system has a defect of not been portable. The valves are attached to the rotted plant, thus truncating the growth of the plant. Sadeky et al. [6] also applied acoustic based mechanism to measure soil moisture in real time method. The technique was based on relationship between speed of sound and the degree of saturation in the soil. The analysis of the design shows that speed of sound decreases as moisture content decreases. The limitation of the work was inability to factor into the design the types of soil. With the literature reviews presented, the research aimed at development of an autonomous mobile plant irrigation robot for a semi structured environment been able to avoid obstacle on its way. The robot design integrate humidity sensor module with an infrared sensor for moisture detecting and obstacle avoidance respectively through an interface of Arduino-Xbee board. The motion of the robot is constraint to only forward motion command. The study is limited for field experiment. 2.1 System Architecture and Description The plant irrigation mobile robot is designed to be able to water a given area of land without human intervention. The robot action is divided into two major phases, which are moisture sensing phase and irrigation phase, implemented by two different modules. The moisture sensing action is achieved using the YL-69 soil sensor, controlled using ATmega328 microcontroller based on arduino platform. The irrigation and mobility of the robot are controlled by DC motors and water pump relay integrated to another Arduino microcontroller to carry out watering action depending on the soil moisture data. The robot’s activity can be divided into two which are plant watering and the robot’s movement activities. The plant watering is shown by the block diagram in figure 1. Figures 2 and 3 show the circuit diagrams of the transmitter and receiver modules. Module 1: Comprises of Zigbee Xbee module (configured as a transmitter), Arduino Uno microcontroller and moisture sensor placed on the area of land to be monitored, LCD and power supply. Module 2: Comprises of Zigbee Xbee module (configured as a receiver), chassis, water tank, a second Arduino Uno microcontroller, DC water pump, IR sensor module. The robot movement stage uses a line following algorithm with the aid of 2 infrared sensor modules. The robot is able to maneuver across a path using a single black line on a white surface. This enables the robot move through the plant spacing on the farmland during sprinkling. The system can carry only a limited amount of water in one go due to it limited water carrying capacity and the weight the DC motors attached. This also restricts the size of the working area. Since a DC power is supplied to the water pump, the configuration of water pump is taken to be 12V or less. The water pump is triggered using a 6V relay which acts like a switch to toggle it instead of physical touching. For a relay to trigger, an external 9-volt power supply is required.
Adeodu, A.O et al./ Procedia Manufacturing 00 (2019) 000–000 A.O. Adeodu et al. / Procedia Manufacturing 35 (2019) 9–15
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The moisture sensor module is mounted close to the soil so as to easily detect the level of humidity of the soil.
Figure 1: Block Diagram of the System
2.2 System Design The transmitter and receiver circuits were initially designed and tested on a solderless breadboard considering all the components involved and power supply before soldering on a veroboard. 2.2.1 Circuit Design of the Transmitter Module The following components were used in designing the transmitter module i. YL-69 Soil Moisture Sensor: YL-69 soil moisture sensor is placed in the soil where the plants to be watered are located to sense the moisture content values of the soil and analyze its watering needs accordingly. It comprises of a two legged Lead, that goes into the soil or anywhere else where water content has to be measured. It has two header pins which connect to an Amplifier/ A-D circuit which is in turn connected to the Arduino. ii. 1602 Liquid Crystal Display (LCD): The LCD gives real-time information of the moisture content of the soil at a remote location from the irrigation robot (receiver module). It is interfaced with an I2C module to simplify the connections to the arduino. The module converts the 16 pin interface on the LCD into 4 pins. iii. Xbee (Series 1) Module (Transmitter Configuration) Xbee is the wireless communication device used to transmit moisture content data of the soil to the mobile robot wirelessly. It covers a linear range of about 300 ft (~100m). iv. Power Supply Power supply to the transmitter module is achieved using a 9 V battery connected to the power port of the arduino. Other components derive their power form the arduino. 2.2.2 Circuit Design of the Receiver Module The following components were used in designing the receiver module i. L293D and DC motors Two 12 V geared motors were used to drive the irrigation robot. They were controlled by a single L293D IC. ii. Design of Motor Expected volume of water to be carried in one cycle, 𝑉𝑉w = 3 𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 =3.00×10−3 𝑚𝑚3 Mass of water, mw = 𝜌𝜌𝜌𝜌=1000× 3.0×10−3 = 3.00 𝑘𝑘𝑘𝑘 Approximate mass of robot (wheels + water + pump + electronics) = 4.0 𝑘𝑘𝑘𝑘
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Adeodu, A.O et al./ Procedia Manufacturing 00 (2019) 000–000 A.O. Adeodu et al. / Procedia Manufacturing 35 (2019) 9–15
Estimated total mass = 4.5 kg Required theoretical velocity of robot, 𝑣𝑣 = 0.3 𝑚𝑚/𝑠𝑠 Required acceleration of robot = 𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟 𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣/𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡 = 0.3/3= 0.1 𝑚𝑚/𝑠𝑠2 Total force required to drive total robot mass = 4.5 × 0.1= 0.45 𝑁𝑁 Robot would use 2 primary motors for movement, Therefore, each motor only needs to supply 1/2 × 0.45 = 0.225 𝑁𝑁 Measured wheel diameter = 0.0865 𝑚𝑚 Minimum theoretical torque required from each wheel = 𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡 𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓 × 𝑑𝑑𝑑𝑑𝑑𝑑𝑡𝑡𝑎𝑎𝑎𝑎𝑎𝑎𝑒𝑒 (𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑) = 0.225× 0.0865 = 0.0195 kgm =𝟎𝟎.𝟏𝟏𝟏𝟏𝟏𝟏 𝐍𝐍𝐍𝐍
iii. IR Sensor This IR sensor utilizes a TCRT5000 to detect colour and distance. Two of said sensor were used to detect obstacles during the motion of the mobile robot.
iv. Relay and Water Pump The Arduino Uno is not able to control the 12 V pump directly due to the voltage and current drawn by the pump, however, a 12 V single channel relay module (SPDT) was used for switching the pump to control its ON and OFF states. v. Design of Pump Maximum flow rate of pump, 𝑄𝑄max =240 𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 𝑝𝑝𝑝𝑝𝑝𝑝 ℎ𝑜𝑜𝑜𝑜𝑜𝑜 = 6.67× 10−5 𝑚𝑚3/𝑠𝑠 Time taken before water is exhausted during sprinkling, 𝑡𝑡 = 𝑉𝑉w/𝑄𝑄max = 22.49 𝑠𝑠 Distance of sprinkling for 1 cycle, 𝑆𝑆 = 𝑣𝑣 × 𝑡𝑡 = 0.3×22.49 = 6.75 𝑚𝑚 , as shown in Figure 2 From plant spacing, total distance of sprinkling from A to B The extra 0.25m is left to account for over-sprinkling, since efficiency is not always 100% . Since distance of sprinkling for 1 cycle is greater than total distance of sprinkling, the robot will not run out of water. vi. Xbee (Series 1) Module (Receiver Configuration) The connection of the Xbee acting as a receiver is similar to the precious configuration in the transmitter module with the only difference being the Tx pin on the Xbee was connected to Rx pin on the arduino Uno. 3.0 Performance Evaluation The test was done on a flat, smooth farmland with plant spacing and maximum slope angle of 1.0 m x 0.5 m and 2o, respectively during the plant growing season. The system layout configuration is shown in Figure 2 it indicates robot path and range of sprinkling.
Figure 2: System Layout Configuration
Adeodu, A.O et al./ Procedia Manufacturing 00 (2019) 000–000 A.O. Adeodu et al. / Procedia Manufacturing 35 (2019) 9–15
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3.1 Relationship between Volume of Water used during Sprinkling and Time Figure 3 shows variation of the amount of water consumed (in litres) with time during a sprinkling cycle. Considering that the robot’s tank capacity from the graph, it can be deduced based on flow rate of the pump, that the water would be exhausted above 100 seconds. So a complete sprinkling cycle would last for about 2:30 minutes.
Figure 3: Graph of Volume of Water against Time
3.2
Soil Moisture Data at Different Times of the Day
From Figure 4, it can be deduced that the moisture content during evening is lower than morning when irrigation has been carried out. The blue curve indicates high moisture content. The red curve indicates low moisture content during evening hours after irrigation has been carried out by the robot in the morning. Distribution was carried out over a period of 7 days as shown in Table 1. Table 1. Variation of Moisture Content against Time day
morning
evening
1
810
387
2
955
344
3
754
404
4
709
290
5
880
323
6
732
461
7
910
308
614
Adeodu, A.O. A.O et al./ Procedia 00 (2019) 35 000–000 Adeodu et al. / Manufacturing Procedia Manufacturing (2019) 9–15
Figure 4: Graph of Moisture Content against Time
3.3 Relationship between Volume of Water Carried and Speed of the Mobile Robot From the motor calculations in section 2, minimum theoretical torque required from each wheel is 𝟎𝟎.𝟏𝟏𝟏𝟏𝟏𝟏 𝑵𝑵𝑵𝑵. Therefore, 2 driver wheels produce a total torque of 0.382 𝑁𝑁𝑁𝑁 (38.2 𝑁𝑁𝑁𝑁𝑁𝑁) meaning the robot is able to move ≈38 𝑁𝑁 in 1 𝑐𝑐𝑐𝑐. No load velocity of robot is approximately 0.8 𝑚𝑚/𝑠𝑠 from testing and is shown in Table 2. When carrying capacity of the tank exceeds 3.5 𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 (3.5×10−3𝑚𝑚) = 34.335𝑁𝑁, the robot would not be able to move and the motors would be stalled as shown in Figure 5. Table 2. Speed Variation with Water Volume of Tank S/N Volume Speed (m/s) (liters) 1 0 0.8 2
0.5
0.5
3
1
0.4
4
1.5
0.2
5
2
0.09
6
2.5
0.06
7
3
0.01
8
3.5
0.005
9
4
0
10
4.5
0
Figure 5 Graph of Speed Variation with Volume
Adeodu, A.O et al./ Procedia Manufacturing 00 (2019) 000–000 A.O. Adeodu et al. / Procedia Manufacturing 35 (2019) 9–15
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4.0 Conclusion The wireless plant irrigation robot system constructed based on ZigBee overcomes the limitations of the fixed sprinkler system and avoids large space consumption. The system performance shows that it’s efficient and cost effective. 4.1 Recommendations The following improvements can be made to the project to increase efficiency and accessibility. i. The use of solar panels and rechargeable batteries to make the system efficient, reliable, and selfsustainable. ii. Incorporate the remote system management via Android smart-phones using the internet iii. Plant detection and obstacle avoidance can be improved via a wireless web camera and ultrasonic sensors, respectively. References [1] N. Hema, A. Reema, and M. Monisha. “Plant Watering Autonomous Mobile Robot”. International Journal of Robotics and Automation. Vol. 1(3), 2012, pp 152-162 [2] B. C. Wolverton, A. Johnson, and K. Bounds, “Interior Landscape Plants for Indoor Air Pollution Abatement: Final Report”, National Aeronautics and Space Administration (NASA-TM-101768) Science and Technology Laboratory, Stennis Space Center, 1989. [3] K. Sikorski, “A Robotic Plant Care System”, A Thesis, University of Washington, Intel Research, 2003. [4] A. Kawakami, K. Tsukada, K. Kambara and I. Siio, “PotPet: Pet-like Flowerpot Robot”, Tangible and Embedded Interaction, ACM New York, NY, USA, 2011, Pages 263-264. [5] C. M. Angelopoulos, S. Nikoletseas, G. C. Theofanopoulos, “A Smart System for Garden Watering using Wireless Sensor Networks”, MobiWac 11, Proceedings of the 9th ACM International Symposium on Mobility Management and Wireless Access, New York, NY, USA, 2011, Pages 167-170. [6] S. Sadeky, A. Al-Hamadiy, B. Michaelisy, and U. Sayedz”, An Acoustic Method for Soil Moisture Measurement”, IEEE 2004