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Approach to the analysis of user requirements in assistive technology
lnternat~onalJoutnalof
Industrial Ergonomics ELSEVIER
International Journal of Industrial Ergonomics 17 (1996) 187-192
Approach to the analysis of user requirements in assistive technology Christian Biihler Forschungsinstitut Technologie-Behindertenhilfe (FTB) der Evangelischen Stiftung Volmarstein, Grundsch6ttelerstr. 40, D-58300 Wetter, Germany Received 2 August 1994; accepted 5 April 1995
Abstract Assistive technology plays an important role for independent living of people with special needs. Therefore it is a key issue to identify the problems that come up in the everyday use of assistive technology. The analysis of user requirements is one of the most important factors for effective special needs developments. The user involvement in every step of the development procedure is meaningful. Especially the experiences of long-term users are very helpful. In case of new technology prototype testing by users during the development can correct the aims by giving unexpected inputs. Although some research activities with user involvement are going on, it still needs more concern in industry and appropriate methodologies have to be established. In this paper two different examples of user involvement are described with respect to the different users' experience. As an example of emerging technologies the use of a robotic aid is investigated. In this case the analysis of user requirements is based on tests of available prototypes with users. As an example of already existing technical aids an investigation of practical user experiences with wheelchairs is described. In both cases the experiences of the users are fed back to the development to achieve real improvement. Our experiences may stimulate researchers and industrialists to initiate user involvement within their activities.
Keywords: Assistive technology; Rehabilitation technology; Technical aids; Rehabilitation robotics; Wheelchairs; User requirements capture; User involvement; Disability; Handicap
1. Feedback of user requirements T h e direct involvement of users provides imp o r t a n t guidance during the design process towards user-friendly and effective products (Biihler and Schmidt, 1993). T h e use o f assistive technology is very c o m m o n today, but often leads to problems in practice. C o n c e r n i n g i n d e p e n d e n c e m a n y problems remain unsolved. T h e r e f o r e it is a
key issue to find out what the practical problems are with already used technology and which problems have not b e e n addressed by now. T h e concept of evaluation and assessment together with the end users is a driving force for the developm e n t and use of new technology for p e o p l e with special needs. It starts with a user-based analysis. In case of emerging technology it discusses user requirements with users and staff and gives t h e m
0169-8141/96/$15.00 © 1996 Elsevier Science B.V. All rights reserved SSDI 0169-8141(95)00049-6
188
C Biihler /International Journal of lndustrial Ergonomics 17 (1996) 187-192
an idea what is possible from technology. Rapidprototyping and test of technology with users follow during the development. This leads to field tests and studies at the end of the development. In case of already existing technical aids this is an analysis of practical user experiences. Closing the circle one can proceed again with new development (Fig. 1). The approach towards user involvement of FTB, used in the context of the project PMMA (Personal Mobile Manipulation Assistance, Project 7513 under the European Programme ESPRIT), concerning robotic aids as emerging and wheelchairs as existing technologies, is described. 2. The investigation of a robotic aid
The use of robotic systems opens new opportunities for people with disabilities (tetraplegia, spinal cord injuries, etc.) at work and in their private homes (Kassler, 1993; Jackson, 1993; Erftring and Neveryd, 1993; Kawamura and
Iskarous, 1994). Wheelchair-mounted arms are of particular importance with respect to activities of daily living, as they are available with the wheelchair on different locations (Oderud and Bastiansen, 1992). Only limited experiences in rehabilitation practice with robots exist, e.g. with the MANUS manipulator (Verburg et al., 1992) or the HANDY 1 (Whittaker, 1992). As part of the project "integrated control systems for the handicapped and the elderly people" therefore the usability of a wheelchair-mountable manipulator has been examined. The manipulator is to be used by disabled persons (e.g. muscular dystrophy) as an appliance for tasks which these people cannot perform by themselves because of a lack of hand power or restricted gross and fine motor functions. 2.1. The wheelchair-mounted robot
Different wheelchairs have been used as mounting bases depending on the wishes of our
new technology I
idea
\ assessment
prototype
[ Fig. 1. Feedback of user requirements.
technical aid
C. Biihler / International Journal of Industrial Ergonomics 17 (1996) 187-192
Fig. 2. Robot integrated with wheelchair.
users (Biihler and Heck, 1993). The wheelchairs have been equipped with the MANUS Manipulator (Exact Dynamics, 1993). The arm has 7 degrees of freedom and can handle a payload of about 2 kg from the floor up to above the head of a sitting person. It has been fixed on the side of the wheelchairs, with the control box either at the back or below the seat (Fig. 2). The battery of the wheelchair supplies the power. The robot is operated by a 4 × 4 matrix of function keys, where each configuration of keys is called a patchboard (Kwee et al., 1992). In order to optimise operation, new patchboards have been set up after the first tests, based on the demands of the users and ergonomical considerations. As a result, complex tasks can be operated as a simple sequence of keys. The control of the wheelchair and the robot are completely separated and an extra input for the wheelchair is needed. 2.1.1. Tests with users
The wheelchair-mounted manipulator has been tested by persons with different disabilities (2 with muscular dystrophy, 4 with spastic tetraplegia, 1 with poliomyelitis, 5 with ICP, 1 with spina bifida, all aged between 20-40). The first user test was divided in two steps: 1. learning phase, in which the physical and mental abilities of the users were determined; 2. test phase. The standard mini-keyboard was used as control device. All users of the test have remaining hand functions, which enabled them in principle to
189
operate the keyboard. The objective was to find out to what extent the different users could operate the robot through the keyboard after a short training period and to identify the actual limitations of the input and arm performance. The simple test task was to drive to a work position and to build a tower of three wooden pieces. Five of the testing persons did not perform the task successfully within the allotted time. All users reported on their experience after the tests. The operation of the coordination of linear movements in the three dimensions was subjectively judged as good by 3, medium by 4 and bad by 6 users. The standard keyboard itself could be used, but was a poor solution for 8 users due to different reasons. The need to switch between patchboards was in practice very unsatisfactory, as it is connected with the change of the functions of the keyboard keys. This configuration of the patchboards was assessed very negatively by the users. The badly arranged functionality caused many mistakes and could all in all lead to refusal/rejection of the manipulator. Furthermore the separate joystick control of the wheelchair and the keyboard control of the manipulator was recognised as to be limiting. This makes further development of the user interface inevitable. The second set of tests was performed with the two most skilled users (both male) at their workplace and private environment with A D L (activities of daily living) tasks. Both were selected because they could control and finish a task in a reasonable time (also from their own point of view). An improved configuration of ergonomical and task-oriented patchboards in combination with an individualised keyboard was used. They tested the execution of daily tasks according to their individual demands. Some typical tasks are: to eat, drink and pour out; to take care of oneself (Fig. 3); - to open doors and drawers; to grab and handle objects (Fig. 4); to get papers out of a file; - to pick up objects from the floor/ground. One of the users (with muscular dystrophy) did perform all these tasks properly and quickly with-
-
-
-
190
C. Biihler/ International Journal of Industrial Ergonomics 17 (1996) 187-192
Fig. 3. Daily task shaving.
out major problems. He is still working intensively with the robot from his own wheelchair. The other person (with spastic tetraplegia) had more problems and asked to operate the robot only at a fixed work-station.
2.2. Summarised results from the test of the robot The tests have shown that the qualities of this system increased the radius of action of the users and supports an independent and self-determined life. Overall it has to be noticed that all our users were keen to enhance their manipulatory capabilities by the robot. However, we recog-
nised that a certain cognitive ability is needed to make real use of the current system. Most problems relate to the input device. The predefined movements in relation to the individual users' needs are critical issues for success. Although the configuration of the patchboards has been adapted to the users' needs, the operation of the keyboard and the lack of automatic movements brought up the current limitations of the system. In order to give a person in a wheelchair more personal freedom, one should have all necessary aids at h e r / h i s disposal via one uniform interface. This would make it easier to communicate with the environment and at the same time enable the user to check and control h e r / h i s aid. Such an integrated control interface should control e.g. the wheelchair, the manipulator, and environmental control activities such as light, TV, etc. In principle the mobility of the total system was appreciated by all users, but the enlarged width of the wheelchair (when driving through corridors or doors) and the separated control were noticed as significant disadvantages. While the disadvantage of the width can be solved by the use of a chair with small wheels in front, the control and operation problems have stimulated further development of the H u m a n - M a c h i n e interface.
3. Study on the use of wheelchairs
Fig. 4. Handling of goods from the bed.
In the area of wheelchairs different levels of expertise of users exist. Therefore it is possible to take advantage of this knowledge and to analyse the situation based on long-term use. The investigation of wheelchairs considered chairs in everyday use and the needs and wishes of the users. About 370 users of wheelchairs were addressed in a vocational training-centre, in a school, at workplaces and in living-facilities including those of elderly people. This group contains a variety of different impairments and disabilities of different ages and represents a large spectrum of users. We used mainly structured interviews based on a two-step questionnaire, and discussions with long-term users.
C. Biihler / International Journal of Industrial Ergonomics 17 (1996) 187-192
3.1. The inquiries Based on literature (e.g. DFVLR, 1984; Batavia and Hammer, 1990; Giannini et al., 1990) and staff experience a list of criteria of wheelchairs was elaborated and a questionnaire developed which was subdivided in three sections: - wheelchair, propelled by an assisting person, - manual-driven wheelchair, - wheelchair with electric propulsion. (There was no experience with scooters among the user group. Therefore they have not been considered.) In interviews and separate discussions with therapists, nursing personnel and physicians the questionnaire was revised and extended. Then the questionnaire was commented on by experienced long-term users of wheelchairs of different ages and handicap. The final version of the questionnaire - three completely revised sections was presented to both long-term users and staff, and approved for distribution. The principal structure of the questionnaires is shown in Table 1. The first part is handed out to all the users and provides an overview of the user spectrum involved. The second part goes more into technical details and seeks information relating to user
Table 1 Principal structure of the questionnaires Part 1
Part 2
Particulars Function at Stiftung Volmarstein Kind of impairment Period of time of wheelchair use Number and kind of wheelchairs used incl. dates about manufacturer and model Kind of use Ranges of activity Contentment Problems Suggestions for modifications
Kind of use Ranges of activity Requirements Reliability Security Seating/Posture Suitability for traffic Properties of moving Usability Comfort of motions Maintenance Practical experiences Open problems Suggestions for modifications Special wishes
191
experience. This second part is distributed to a group of persons who were selected from the general overview of the users' spectrum from part one. After the first evaluation of the second questionnaire a series of interviews followed. The selected group was confronted with the results and separately interviewed.
3.2. Summarised results from the inquiries about wheelchairs We got a very sophisticated picture of wheelchair use in Evangelische Stiftung Volmarstein, which describes the very different experiences of users of all ages and various impairments. Insufficient seating and posture was the main problem with the basic standard wheelchairs. Many of our users gave priority to high manoeuvrability instead of stability of movement. A lot of suggestions and wishes considered the operability in everyday use: space for luggage, an individual key, space for walking aids, integrated charging device, etc. Asked for the most important criteria, reliability got the highest attention with electrical wheelchairs. Often problems with the electronics were pointed out, especially insufficient water resistance. A lot of people also mentioned battery-related problems like charging, maintenance or estimation of distance within range. In all, the investigation gave us the necessary user background for our future work in wheelchair development. The set-up of a group of user experts for further cooperation was another important result of the investigation.
4.
Conclusions
To achieve real progress in the field of assistive technology, a precise interweave of development and application is required. This enables system optimisation in the sense of a control loop with respect to the most important output value the availability of effective technical aids and their real use. This includes several repetitions of periods of development and tests. In any case, the problems of acceptance by the users and their
192
C Biihler / International Journal of lndustrial Ergonomics 17 (1996) 187-192
experiences in the examinations have to be considered. As there exist no extensive long-term experiences with robot technologies from the actual practice in the rehab area, user trials are of particular importance. In the case of established assistive techriology such as wheelchairs the experiences of long-term users are of high importance. The results of the investigations described above have been introduced in further developments, e.g. in OMNI (office wheelchair with high manoeuvrability), IMMEDIATE (project on Integrated Systems using proposal M3S for a standard communication protocol) and UNIFACE (project on uniform control interfaces). From our experience the procedure of user involvement needs quite an effort, but the impact on development is tremendous. Unfortunately this has not yet been recognised everywhere, which causes a scarcity of financial resources. Hopefully this will change with the wider notice of the real benefit of user requirements analysis.
Re~rences Batavia, A.I. and Hammer, G.S., 1990. Toward the development of consumer-based criteria for the evaluation of
assistive devices. Journal of Rehabilitation Research and Development (Dept. of Veterans Affairs), 27 (4): 425-436. Biihler, Ch. and Heck, H., 1993, RoUstuhlmontiertes Handhabungssystem ffir Menschen mit Handicap. In: VDI Berichte 1094, VDI-Verlag, Diisseldorf, pp. 153-164. Biihler, Ch. and Schmidt, M., 1993, User involvement in evaluation and assessment of assistive technology. ECART2, Stockholm 26-28.5. 1993, 30.1. DFVLR (Ed.), 1984. Rollstuhlentwicklung Deutsch-Britisches Statuskolloquium. Reha-Verlag, Bonn. Erftring, H. and Neveryd, H., 1993. Rehabilitation robotics at CERTEC. Rehabilitation Robotics Newsletter, 5(4). Giannini, M.J. et al., 1990. Choosing a wheelchair system. Clinical supplement #2, Journal of Rehabilitation Research and Development, 2. Jackson, R.D., 1993. Robotics and its role in helping disabled people. Engineering Science and Educational Journal, 2: 267-272. Kassler, M., 1993. Robotics for health care: A review of the literature. Robotica, 11: 495-516. Kawamura, K. and Iskarous, I., 1994. Trends in service robotics for the disabled and the elderly. Proc. of I E E E / R S J / G I International Conference on Intelligent Robots and Systems, Munich, September 1994, 1647-1654. Kwee, H. et al., 1992. Configuring the MANUS system. Proc. of RESNA Conference 92. June 1992, 584-587. MANUS Product description. Exact Dynamics, Netherlands, 1993. ~derud, T. and Bastiansen, J.E., 1992. Integrating a Manus Manipulator and an electric wheelchair: Practical experiences. Proc. of RESNA Conference, June 1992, 595-597. Verburg, G. et al., 1992. An evaluation of the wheelchairmounted manipulator. Proc. of RESNA Conference 92, June 92, 602-604. Whittaker, M., 1992. HANDY 1 robotic aid to eating: A study of social impact. Proc. of RESNA Conference 92, June 92, 589-594.
Industrial Ergonomics ELSEVIER
International Journal of Industrial Ergonomics 17 (1996) 187-192
Approach to the analysis of user requirements in assistive technology Christian Biihler Forschungsinstitut Technologie-Behindertenhilfe (FTB) der Evangelischen Stiftung Volmarstein, Grundsch6ttelerstr. 40, D-58300 Wetter, Germany Received 2 August 1994; accepted 5 April 1995
Abstract Assistive technology plays an important role for independent living of people with special needs. Therefore it is a key issue to identify the problems that come up in the everyday use of assistive technology. The analysis of user requirements is one of the most important factors for effective special needs developments. The user involvement in every step of the development procedure is meaningful. Especially the experiences of long-term users are very helpful. In case of new technology prototype testing by users during the development can correct the aims by giving unexpected inputs. Although some research activities with user involvement are going on, it still needs more concern in industry and appropriate methodologies have to be established. In this paper two different examples of user involvement are described with respect to the different users' experience. As an example of emerging technologies the use of a robotic aid is investigated. In this case the analysis of user requirements is based on tests of available prototypes with users. As an example of already existing technical aids an investigation of practical user experiences with wheelchairs is described. In both cases the experiences of the users are fed back to the development to achieve real improvement. Our experiences may stimulate researchers and industrialists to initiate user involvement within their activities.
Keywords: Assistive technology; Rehabilitation technology; Technical aids; Rehabilitation robotics; Wheelchairs; User requirements capture; User involvement; Disability; Handicap
1. Feedback of user requirements T h e direct involvement of users provides imp o r t a n t guidance during the design process towards user-friendly and effective products (Biihler and Schmidt, 1993). T h e use o f assistive technology is very c o m m o n today, but often leads to problems in practice. C o n c e r n i n g i n d e p e n d e n c e m a n y problems remain unsolved. T h e r e f o r e it is a
key issue to find out what the practical problems are with already used technology and which problems have not b e e n addressed by now. T h e concept of evaluation and assessment together with the end users is a driving force for the developm e n t and use of new technology for p e o p l e with special needs. It starts with a user-based analysis. In case of emerging technology it discusses user requirements with users and staff and gives t h e m
0169-8141/96/$15.00 © 1996 Elsevier Science B.V. All rights reserved SSDI 0169-8141(95)00049-6
188
C Biihler /International Journal of lndustrial Ergonomics 17 (1996) 187-192
an idea what is possible from technology. Rapidprototyping and test of technology with users follow during the development. This leads to field tests and studies at the end of the development. In case of already existing technical aids this is an analysis of practical user experiences. Closing the circle one can proceed again with new development (Fig. 1). The approach towards user involvement of FTB, used in the context of the project PMMA (Personal Mobile Manipulation Assistance, Project 7513 under the European Programme ESPRIT), concerning robotic aids as emerging and wheelchairs as existing technologies, is described. 2. The investigation of a robotic aid
The use of robotic systems opens new opportunities for people with disabilities (tetraplegia, spinal cord injuries, etc.) at work and in their private homes (Kassler, 1993; Jackson, 1993; Erftring and Neveryd, 1993; Kawamura and
Iskarous, 1994). Wheelchair-mounted arms are of particular importance with respect to activities of daily living, as they are available with the wheelchair on different locations (Oderud and Bastiansen, 1992). Only limited experiences in rehabilitation practice with robots exist, e.g. with the MANUS manipulator (Verburg et al., 1992) or the HANDY 1 (Whittaker, 1992). As part of the project "integrated control systems for the handicapped and the elderly people" therefore the usability of a wheelchair-mountable manipulator has been examined. The manipulator is to be used by disabled persons (e.g. muscular dystrophy) as an appliance for tasks which these people cannot perform by themselves because of a lack of hand power or restricted gross and fine motor functions. 2.1. The wheelchair-mounted robot
Different wheelchairs have been used as mounting bases depending on the wishes of our
new technology I
idea
\ assessment
prototype
[ Fig. 1. Feedback of user requirements.
technical aid
C. Biihler / International Journal of Industrial Ergonomics 17 (1996) 187-192
Fig. 2. Robot integrated with wheelchair.
users (Biihler and Heck, 1993). The wheelchairs have been equipped with the MANUS Manipulator (Exact Dynamics, 1993). The arm has 7 degrees of freedom and can handle a payload of about 2 kg from the floor up to above the head of a sitting person. It has been fixed on the side of the wheelchairs, with the control box either at the back or below the seat (Fig. 2). The battery of the wheelchair supplies the power. The robot is operated by a 4 × 4 matrix of function keys, where each configuration of keys is called a patchboard (Kwee et al., 1992). In order to optimise operation, new patchboards have been set up after the first tests, based on the demands of the users and ergonomical considerations. As a result, complex tasks can be operated as a simple sequence of keys. The control of the wheelchair and the robot are completely separated and an extra input for the wheelchair is needed. 2.1.1. Tests with users
The wheelchair-mounted manipulator has been tested by persons with different disabilities (2 with muscular dystrophy, 4 with spastic tetraplegia, 1 with poliomyelitis, 5 with ICP, 1 with spina bifida, all aged between 20-40). The first user test was divided in two steps: 1. learning phase, in which the physical and mental abilities of the users were determined; 2. test phase. The standard mini-keyboard was used as control device. All users of the test have remaining hand functions, which enabled them in principle to
189
operate the keyboard. The objective was to find out to what extent the different users could operate the robot through the keyboard after a short training period and to identify the actual limitations of the input and arm performance. The simple test task was to drive to a work position and to build a tower of three wooden pieces. Five of the testing persons did not perform the task successfully within the allotted time. All users reported on their experience after the tests. The operation of the coordination of linear movements in the three dimensions was subjectively judged as good by 3, medium by 4 and bad by 6 users. The standard keyboard itself could be used, but was a poor solution for 8 users due to different reasons. The need to switch between patchboards was in practice very unsatisfactory, as it is connected with the change of the functions of the keyboard keys. This configuration of the patchboards was assessed very negatively by the users. The badly arranged functionality caused many mistakes and could all in all lead to refusal/rejection of the manipulator. Furthermore the separate joystick control of the wheelchair and the keyboard control of the manipulator was recognised as to be limiting. This makes further development of the user interface inevitable. The second set of tests was performed with the two most skilled users (both male) at their workplace and private environment with A D L (activities of daily living) tasks. Both were selected because they could control and finish a task in a reasonable time (also from their own point of view). An improved configuration of ergonomical and task-oriented patchboards in combination with an individualised keyboard was used. They tested the execution of daily tasks according to their individual demands. Some typical tasks are: to eat, drink and pour out; to take care of oneself (Fig. 3); - to open doors and drawers; to grab and handle objects (Fig. 4); to get papers out of a file; - to pick up objects from the floor/ground. One of the users (with muscular dystrophy) did perform all these tasks properly and quickly with-
-
-
-
190
C. Biihler/ International Journal of Industrial Ergonomics 17 (1996) 187-192
Fig. 3. Daily task shaving.
out major problems. He is still working intensively with the robot from his own wheelchair. The other person (with spastic tetraplegia) had more problems and asked to operate the robot only at a fixed work-station.
2.2. Summarised results from the test of the robot The tests have shown that the qualities of this system increased the radius of action of the users and supports an independent and self-determined life. Overall it has to be noticed that all our users were keen to enhance their manipulatory capabilities by the robot. However, we recog-
nised that a certain cognitive ability is needed to make real use of the current system. Most problems relate to the input device. The predefined movements in relation to the individual users' needs are critical issues for success. Although the configuration of the patchboards has been adapted to the users' needs, the operation of the keyboard and the lack of automatic movements brought up the current limitations of the system. In order to give a person in a wheelchair more personal freedom, one should have all necessary aids at h e r / h i s disposal via one uniform interface. This would make it easier to communicate with the environment and at the same time enable the user to check and control h e r / h i s aid. Such an integrated control interface should control e.g. the wheelchair, the manipulator, and environmental control activities such as light, TV, etc. In principle the mobility of the total system was appreciated by all users, but the enlarged width of the wheelchair (when driving through corridors or doors) and the separated control were noticed as significant disadvantages. While the disadvantage of the width can be solved by the use of a chair with small wheels in front, the control and operation problems have stimulated further development of the H u m a n - M a c h i n e interface.
3. Study on the use of wheelchairs
Fig. 4. Handling of goods from the bed.
In the area of wheelchairs different levels of expertise of users exist. Therefore it is possible to take advantage of this knowledge and to analyse the situation based on long-term use. The investigation of wheelchairs considered chairs in everyday use and the needs and wishes of the users. About 370 users of wheelchairs were addressed in a vocational training-centre, in a school, at workplaces and in living-facilities including those of elderly people. This group contains a variety of different impairments and disabilities of different ages and represents a large spectrum of users. We used mainly structured interviews based on a two-step questionnaire, and discussions with long-term users.
C. Biihler / International Journal of Industrial Ergonomics 17 (1996) 187-192
3.1. The inquiries Based on literature (e.g. DFVLR, 1984; Batavia and Hammer, 1990; Giannini et al., 1990) and staff experience a list of criteria of wheelchairs was elaborated and a questionnaire developed which was subdivided in three sections: - wheelchair, propelled by an assisting person, - manual-driven wheelchair, - wheelchair with electric propulsion. (There was no experience with scooters among the user group. Therefore they have not been considered.) In interviews and separate discussions with therapists, nursing personnel and physicians the questionnaire was revised and extended. Then the questionnaire was commented on by experienced long-term users of wheelchairs of different ages and handicap. The final version of the questionnaire - three completely revised sections was presented to both long-term users and staff, and approved for distribution. The principal structure of the questionnaires is shown in Table 1. The first part is handed out to all the users and provides an overview of the user spectrum involved. The second part goes more into technical details and seeks information relating to user
Table 1 Principal structure of the questionnaires Part 1
Part 2
Particulars Function at Stiftung Volmarstein Kind of impairment Period of time of wheelchair use Number and kind of wheelchairs used incl. dates about manufacturer and model Kind of use Ranges of activity Contentment Problems Suggestions for modifications
Kind of use Ranges of activity Requirements Reliability Security Seating/Posture Suitability for traffic Properties of moving Usability Comfort of motions Maintenance Practical experiences Open problems Suggestions for modifications Special wishes
191
experience. This second part is distributed to a group of persons who were selected from the general overview of the users' spectrum from part one. After the first evaluation of the second questionnaire a series of interviews followed. The selected group was confronted with the results and separately interviewed.
3.2. Summarised results from the inquiries about wheelchairs We got a very sophisticated picture of wheelchair use in Evangelische Stiftung Volmarstein, which describes the very different experiences of users of all ages and various impairments. Insufficient seating and posture was the main problem with the basic standard wheelchairs. Many of our users gave priority to high manoeuvrability instead of stability of movement. A lot of suggestions and wishes considered the operability in everyday use: space for luggage, an individual key, space for walking aids, integrated charging device, etc. Asked for the most important criteria, reliability got the highest attention with electrical wheelchairs. Often problems with the electronics were pointed out, especially insufficient water resistance. A lot of people also mentioned battery-related problems like charging, maintenance or estimation of distance within range. In all, the investigation gave us the necessary user background for our future work in wheelchair development. The set-up of a group of user experts for further cooperation was another important result of the investigation.
4.
Conclusions
To achieve real progress in the field of assistive technology, a precise interweave of development and application is required. This enables system optimisation in the sense of a control loop with respect to the most important output value the availability of effective technical aids and their real use. This includes several repetitions of periods of development and tests. In any case, the problems of acceptance by the users and their
192
C Biihler / International Journal of lndustrial Ergonomics 17 (1996) 187-192
experiences in the examinations have to be considered. As there exist no extensive long-term experiences with robot technologies from the actual practice in the rehab area, user trials are of particular importance. In the case of established assistive techriology such as wheelchairs the experiences of long-term users are of high importance. The results of the investigations described above have been introduced in further developments, e.g. in OMNI (office wheelchair with high manoeuvrability), IMMEDIATE (project on Integrated Systems using proposal M3S for a standard communication protocol) and UNIFACE (project on uniform control interfaces). From our experience the procedure of user involvement needs quite an effort, but the impact on development is tremendous. Unfortunately this has not yet been recognised everywhere, which causes a scarcity of financial resources. Hopefully this will change with the wider notice of the real benefit of user requirements analysis.
Re~rences Batavia, A.I. and Hammer, G.S., 1990. Toward the development of consumer-based criteria for the evaluation of
assistive devices. Journal of Rehabilitation Research and Development (Dept. of Veterans Affairs), 27 (4): 425-436. Biihler, Ch. and Heck, H., 1993, RoUstuhlmontiertes Handhabungssystem ffir Menschen mit Handicap. In: VDI Berichte 1094, VDI-Verlag, Diisseldorf, pp. 153-164. Biihler, Ch. and Schmidt, M., 1993, User involvement in evaluation and assessment of assistive technology. ECART2, Stockholm 26-28.5. 1993, 30.1. DFVLR (Ed.), 1984. Rollstuhlentwicklung Deutsch-Britisches Statuskolloquium. Reha-Verlag, Bonn. Erftring, H. and Neveryd, H., 1993. Rehabilitation robotics at CERTEC. Rehabilitation Robotics Newsletter, 5(4). Giannini, M.J. et al., 1990. Choosing a wheelchair system. Clinical supplement #2, Journal of Rehabilitation Research and Development, 2. Jackson, R.D., 1993. Robotics and its role in helping disabled people. Engineering Science and Educational Journal, 2: 267-272. Kassler, M., 1993. Robotics for health care: A review of the literature. Robotica, 11: 495-516. Kawamura, K. and Iskarous, I., 1994. Trends in service robotics for the disabled and the elderly. Proc. of I E E E / R S J / G I International Conference on Intelligent Robots and Systems, Munich, September 1994, 1647-1654. Kwee, H. et al., 1992. Configuring the MANUS system. Proc. of RESNA Conference 92. June 1992, 584-587. MANUS Product description. Exact Dynamics, Netherlands, 1993. ~derud, T. and Bastiansen, J.E., 1992. Integrating a Manus Manipulator and an electric wheelchair: Practical experiences. Proc. of RESNA Conference, June 1992, 595-597. Verburg, G. et al., 1992. An evaluation of the wheelchairmounted manipulator. Proc. of RESNA Conference 92, June 92, 602-604. Whittaker, M., 1992. HANDY 1 robotic aid to eating: A study of social impact. Proc. of RESNA Conference 92, June 92, 589-594.