Development of an ADL assistance apparatus for upper limbs and evaluation of muscle and cerebral activity of the user

Transcription

1 Bulletin of the JSME Journal of Advanced Mechanical Design, Systems, and Manufacturing Vol.8, No., 04 Development of an ADL assistance apparatus for upper limbs and evaluation of and cerebral activity of the user Eiichirou TANAKA*, Shozo SAEGUSA**, Yasuo IWASAKI*** and Louis YUGE**** * Department of Machinery & Control Systems, Shibaura Institute of Technology 307 Fukasaku, Minuma-ku, Saitama , Japan tanakae@sic.shibaura-it.ac.jp ** Center for Collaborative Research & Community Cooperation, Hiroshima University -33 Kagami-yama, Higashi-Hiroshima, Hiroshima, Japan *** Department of Neurology Toho University Omori Hospital 6-- Omori-nishi, Ota-Ku, Tokyo, Japan **** Graduate School of Biomedical & Health Sciences, Hiroshima University --3 Kasumi, Minami-ku, Hiroshima 734-8, Japan Received October 03 Abstract This assistance apparatus for upper limbs was developed for patients who can control their fingers but they cannot lift up their arms themselves, for example myopathy and hemiplegic patients. The purposes of the research in this paper are as follows: ) to design the simple shaped arm and make the easy control system taking into account the practical use of patients, ) to confirm the decrease of activity while using the apparatus as an ADL assistance device for myopathy patients, 3) to grasp the tendency of the cerebral activity while using the apparatus as a Neuro-Rehabilitation assistance device for hemiplegic patients. The mechanism of assistance is utilizes the differential gears to lose the weight and volume of the mechanical arm. That enabled us to configure three motors to drive two DOFs (Degrees of freedom) for the shoulder and one DOF for the elbow around the root of the mechanical arm. The arm can lift up to 4 kgf (39. N) at the tip of the extended arm, and each maximum angle velocity is.7 rad/sec. This arm has two support trays, for wrist and upper arm. Each tray is equipped with a pressure sensor at the contact point to the user s arm, and by using the measured result of these four sensors, the control computer can learn the status of the user s arms. Furthermore, to realize other ADL (activities of daily living) motions (for instance, eating, writing, putting on making up, wiping his/her face, and so on) themselves, we proposed to control the device using the targeted posture map for the mechanical arm. At first, various desired or necessary postures of the assisted arms for the equipped person are determined, and each posture is defined as a control target. Next, each target (which is relatively close) is mutually connected, and the map can be accomplished. However, most of user can use the device without watching the map, because each target in the map is connected with the input signal of the same direction, which the user wants to move his/her hand. To be able to choose the appropriate input for each patient, various input interfaces, for example, joy-stick, push buttons, sensor glove using bending sensors, and so on, are equipped. The activity while using the device was measured, and compared the %MVC data between using the device or not. As a result, the activity decreased up to 60%, and the effectiveness of this device could be confirmed. Finally, to expand the usage of this apparatus to encompass Neuro-Rehabilitation as well, the cerebral activity while using the device for rehabilitation with a near-infrared spectroscopy (NIRS) was measured. Then the data from using the device or not, and input motion from a third person were compared. By using this device, the cerebral activity decreased especially when the target motion was complex. However, when the subject input the motion themselves, the cerebral activity increased more than the data is input by a third person, especially, according to the complexity of the target motion. Therefore, for use in Neuro-Rehabilitation, we found it was important for the subject to input the target motion him/herself. Keywords : ADL assistance, Muscle and cerebral activity, Neuro-Rehabilitation Paper No.3-007

2 Journal of Advanced Mechanical Design, Systems, and Manufacturing, Vol.8, No. (04). Introduction There are many people throughout the world who cannot raise their arms themselves, due to accidents, myopathy, hemiplegic, and so on, even though they can manipulate their own fingers. Medical doctors and physical therapists have aspired to develop devices which can support their patient s ADL. To address their demands, many institutes and universities have developed various kinds of ADL support devices. Handy (Topping, 999) and My Spoon (Soyama, et al., 003) were developed to assist the severely disabled. By using these devices, the patients can have a meal without using their hands. AIST developed PAPUD (AIST, 009), which is a wheel chair with a robot arm which has seven DOFs. This arm can carry a payload of 0. [kgf] (4.9 [N]), and this device can support the user s ADL movement instead of the user. However, if a patient can use his/her own hand, it is important to use his/her hand by whatever means possible, to regain independence. The Portable Spring Balancer (PSB) (hny International Corporation, 008) was developed for the patient who wants to be as independent as possible. This mechanism is passive assistance with a spring, therefore it cannot assist to guide his/her arm to the direction which the user wants to move. To assist the upper limb with some power sources (e.g. motor or pneumatic actuator), many devices have developed. Watanabe (Watanabe, et al., 0) and Panasonic (Panasonic, 00) developed the device for elbow assistance. These devices are body fitting shape so they can be equipped. However, the weight of the device is imposed for the user, and these are difficult to assist each ADL motions; e.g. eating, make up or washing face because they assist only elbow joint. To assist the spatial motion of the patient, various devices which had multi-degree of freedoms were developed (Tsagarakis and Caldwell, 003, Nef, et al., 006, Perry, et al., 007, Kiguchi, 007, Lucchesi, et al., 00, Sasaki, et al., 03). By using these devices, the user can move his/her own arm according to his/her wishes. Furthermore, these devices are attached an independent frame, therefore the weight of the device is not imposed for the user. However, most of all devices are too balky, and they have many points to worry about the injury when they bump into the user or third party as many comments of the hearing in patients associations. The most important point of developing the device for patients is to design taking into account the practical use for patients from the beginning of the design. As the result of the hearing, we developed an ADL assistance apparatus for upper limbs. The purposes of the research in this paper are as follows: ) to design the simple shaped arm and make the easy control system taking into account the practical use of patients, ) to confirm the decrease of activity while using the apparatus as an ADL assistance device for myopathy patients, 3) to grasp the tendency of the cerebral activity while using the apparatus as a Neuro-Rehabilitation assistance device for hemiplegic patients. That can be used by attaching the arms to the pressure sensor tray, and versatile enough to do various ADL motions. In this paper, the apparatus was evaluated from the view point of and cerebral activity of users while using for ADL and rehabilitation motion assistance.. Mechanism and control method of the assistance apparatus for upper limbs The assistance apparatus for upper limbs (Fig. ) is designed for patients who can control their fingers but they cannot lift their arms themselves, especially myopathy patients. The mechanism of the apparatus utilizes the differential gears to disperse the weight and volume of the mechanical arm, and that enabled us to configure three motors to drive two DOFs (Degrees of freedom) for the shoulder and one DOF for the elbow around the root of the mechanical arm as shown in Fig.. The arm can lift up to [kgf] (9.6 [N]) at the tip of the one extended arm, and each angle velocity is.7 [rad/sec], which was determined from the measured mean data of an able bodied subject s motion. When the subject lifts up something, most of subjects took [sec] and whose knee and shoulder were flexed by about 90 [deg]. Here, the principle of the differential gears of this apparatus is explained. A conventional model is defined as shown in Fig. 3(a), whose input torques are [Nm] and [Nm], and angle velocities are [rad/sec] and [rad/sec]. Each parameter of the arm of the apparatus is shown in Fig. 4. Each torque of the conventional model is calculated by Eq. (). mg s e 3 mgle megleg sin 3 cos l sin l sin m gl sin m g l sin l sin s sg e When a conventional model is adopted, the motor which outputs the torque has to be attached on the mechanical s eg 3 cos ()

3 Journal of Advanced Mechanical Design, Systems, and Manufacturing, Vol.8, No. (04) arm, then the mass m s or m e and the arm becomes bulky. On the contrary, the proposed novel model shown in Fig. 3(b), whose input torques are p [Nm] and q [Nm], and angle velocities are p [rad/sec] and q [rad/sec]. Each torque and angle velocity is calculated by Eqs. () and (3). p, q, (),. p q (3) By using Eqs. () to (3), the torque variations during four typical motions as shown in Fig. were calculated. The main user was assumed as an elderly male whose weight was 70 [kg]. From the database (Nakamura, 007), the values of the weight ratio of each part of human body and whose point of center of gravity, were utilized. And the average lengths of each body part are written in the database (Kouchi, 000). The weights of mechanical upper and lower arms (included each tray) are both 0. [kg]. By using these data, the values of each calculation parameter (which includes the user s upper and lower arm, hand and mechanical arm of the apparatus) were set as m s =4. [kg], m e =.6 [kg], l s =0.8 [m], l sg =0.3 [m], l e =0. [m], l eg =0.09 [m], =0 [deg]. The mass of the load was assumed as m = +hand s weight (.6 [kg]) =.6 [kg]. The results of the calculation were shown in Fig. 6. From the comparison of the torque between the conventional and proposed models in Fig. 6, the total necessary torque has the same value, however, in the proposed model, the maximum torque decreased by 6 [Nm] than the result of the conventional model. Fig. Photos of the ADL assistance apparatus for upper limbs Fig. Mechanism of the assistance device for upper limbs 3

4 Journal of Advanced Mechanical Design, Systems, and Manufacturing, Vol.8, No. (04) (a) Conventional model (b) Proposed novel model Fig. 3 Definition of each torque and angle velocity A z y A-A l e θ l eg x l sg l s θ θ 3 m mgcosq m e gcosq s gcosq A Fig. 4 Each parameter of the arm of the apparatus q : 0 90 [deg] q 3 : 0 [deg] q : 0 [deg] q 3 : 0 90 [deg] q : 0 90 [deg] q 3 : 90 0 [deg] q : 0 90 [deg] q 3 : 0 90 [deg] (a) Case (b) Case (c) Case 3 (d) Case 4 Fig. Four typical motions (a) Case (b) Case (a) Case 3 (b) Case 4 Fig. 6 Calculation results of each torque variation 4

5 Journal of Advanced Mechanical Design, Systems, and Manufacturing, Vol.8, No. (04) The maximum necessary torques of are t p = 0. [Nm] and t q =.7 [Nm], and each motor was selected as follows: t p : FAULHABER 3863H0C38/S, 66/ (Gear head), 8/4 (Pulley), 36/8 (Gear) (90 [W], Rated torque: 0. [Nm]*66/*8/4*36/8 *0.8 (Efficiency) = 3.3 [Nm]) t q : FAULHABER 37K0CR38/S, 66/ (Gear head), 8/4 (Pulley), 48/4 (Gear) (4 [W], Rated torque: 0.08 [Nm]*66/*8/4*48/4*0.8 (Efficiency) = 6.60 [Nm]) Therefore, a relatively low power smaller size motor can be selected. Additionally, the motor for the shoulder abduction (lateral elevation) of q, was selected as FAULHABER 37K0CR38/S, 9/ (Gear head), 60/8 (Pulley) (4 [W], Rated torque: 0.08 [Nm]*9/*60/8*0.8 (Efficiency) = 33.9 [Nm]). To determine each link length of the apparatus and each movable range of the joints, some databases (Nakamura, 007, Kouchi, 000) were referred especially the data of an elderly male, the apparatus was designed the configuration and specifications as shown in Fig. 7 and Table. To be able to use of supporting only upper arm with this device, the angle of elbow for extension is expanded up to 4 [deg]. This arm has two support trays, for the wrist and the upper arm. Each tray is equipped with a pressure sensor at the contact point to the user s arm, and by using the measured result of these four sensors, the control computer can learn the status of the user s arms. Furthermore, to realize other ADL (activities of daily living) motions (for instance, eating, writing, making up, wiping his/her face, and so on) themselves, we proposed to control the device using the targeted posture map for the mechanical arm as shown in Fig. 8. At first, various desired or necessary postures of the assisted arms for the equipped person are determined, and each posture is defined as a control target. Next, each target (which is relatively close) is mutually connected, and the map can be accomplished. To be able to choose the appropriate input way for each patient, various input interfaces, for example, joy-stick, push buttons, sensor glove using bending sensors, and so on, are equipped as shown in Fig. 9. This apparatus control system is shown in Fig. 0. This apparatus can be combined to a lower limb assistance device (Tanaka, 0) as shown in Fig., and used for assisting whole body motion (Tanaka, 03). Even if the apparatus is combined with the walking assistance apparatus (Tanaka, 0) as shown in Fig., the control system can be used by only connecting. The control method for upper limbs is shown in Fig.. At first we utilized the position control method, however, some postures which were difficult for some patients existed. Therefore the method of this apparatus is simple degree control method. The center of Fig. shows the example for assisting to play the violin inputted with the sensor glove, and the right of the Fig. shows the example for the motion of drinking inputted with the joy stick. This target mapping system is for patient safety and gained from patients opinion. Fig. 7 Each length of the apparatus

6 Journal of Advanced Mechanical Design, Systems, and Manufacturing, Vol.8, No. (04) Table Comparison of each motion angle between human and apparatus Body part Axis No. Motion Human [deg] Apparatus [deg] Elebation 0 4 Depression 0 6 Shoulder girdle Flexion 0 0 Extension Shoulder 4 Elbow 6 External rotation Abduction (lateral elevation) Flexion (forward elevation) Flexion Internal rotation Adduction Extension (backward elevation) Extension Fig. 8 Example of the targeted posture map for the assistance device for upper limbs (a) Push switch (b) Joy stick (c) Sensor glove Fig. 9 Input interfaces 6

7 Journal of Advanced Mechanical Design, Systems, and Manufacturing, Vol.8, No. (04) Fig. 0 Control system of the apparatus Fig. Whole body motion support apparatus Fig. Control method of the apparatus 7

8 Journal of Advanced Mechanical Design, Systems, and Manufacturing, Vol.8, No. (04) 3. Somesthetic experiment using the assistance apparatus The subjects were a medical doctor, a physical therapist, two hemiplegic patients, and one myopathy patient who can move her finger but cannot lift up her arm. Beforehand, we got permission to carry out the experiment from the patients and their doctors in charge. The experiment was as follows: ) the subject attached their arms to the pressure sensor tray of the device, ) he/she operates the device using the joy stick or push switch by his/her finger, 3) the subject evaluates the movement of the apparatus toward the targeted point, and user-friendliness by somesthetic feeling. As a result all five subjects could operate the apparatus easily. The doctor said, It may be useful to utilize this apparatus for rehabilitation of upper limbs. The physical therapist said, The posture of the arm can stay on the desk, so by using this device, many patients become able to do various forms of deskwork. The hemiplegic patients said, It is important to adjust it precisely for each individual. However, it was hard for the myopathy patient to use the joy stick, therefore she used the push switch. She said, I was impressed to be able to touch my face by myself. Therefore, we found the device is useful for patients. It also has to be adjusted for an individual s use. For example: input device and placement of pressure sensor tray. 4. Compensation of flow disturbance using estimated signal In general, even though a human behaves an atonic motion, %MVC outputs at least from to 0 [%]. The usage of this apparatus is to move the user s upper limbs with dependence completely, and the purpose of this apparatus is to decrease the value of %MVC up to approximately 0 [%]. Therefore, in this paper, the s of the user were evaluated with the ratio of the maximum voluntary contraction (%MVC). To confirm the effectiveness of assistance ability, we measured the differences of the activity while drinking motion. The subject was an able bodied man (age: ). The experiment can be divided into three motions, ) During the motions of to as shown in Fig. 3, ) During the motions of to 3, 3) During the motions of 3 to. Measured results of the tip of the arm while drinking motion are shown in Fig.4. This apparatus uses degree control method, however, to confirm the follow up ability of this apparatus, the measured and targeted values of angles are converted to the left handed orthogonal coordinate system. The maximum angle velocity of each joint of the device was prepared versions; a).7 [rad/sec] (assumed same velocity as an able bodied person), and b) 0. [rad/sec] (third velocity of.7 [rad/sec]). From fig. 4 (a), a little delay during the motions of to 3 is existed, however, the measured values can be caught the target at each turning point. On the other hand, when the angle velocity is slow version, the difference of each parameter between measured and targeted data remains very small as shown in Fig. 4 (b). Therefore, the follow up ability of this apparatus was confirmed. 3 Fig. 3 Drinking motion using the device 8

9 Journal of Advanced Mechanical Design, Systems, and Manufacturing, Vol.8, No. (04) (a) Maximum angle velocity:.7 [rad/sec] (b) Maximum angle velocity: 0. [rad/sec] Fig. 4 Comparison the tip of the apparatus between measured and targeted data The electromyography (EMG) was measured with Personal-EMG (Oisaka Electronic Equipment Ltd.), which has eight channels. The measured s are ) Deltoid, Anterior, ) Deltoid, Middle, 3) Deltoid, Posterior, 4) Pectroralis Major, ) Biceps Brachii, 6) Triceps Prachii, Lateral Head, 7) Brachioradialis as shown in Fig.. In advance, the maximum voluntary contraction (MVC) of each was measured, and rectified the all waves, and averaged. Next, the EMG during each motion was measured, and rectified and averaged. Then by using these data, %MVC of each during each motion was calculated. The subject carried out the 9

10 Journal of Advanced Mechanical Design, Systems, and Manufacturing, Vol.8, No. (04) measurement while drinking motion three times, ) without the device (normal motion) ) using the device and whose angle velocity was.7 [rad/sec] (assumed same velocity as an able bodied person), 3) using the device and whose angle velocity was 0. [rad/sec] (third velocity of )). The results are shown in Fig. 6. In the motions of to as shown in Fig. 3, the results have almost same values, because the was hardly used at all. However, in the motions of to 3 as shown in Fig. 3, all activity decreased, especially in slow motion s result, up to by about 60%. When the device drives slowly and it assists to raise the user s arm, the user feels secure, and increases the dependence on the device. In the motions of 3 to, the activity is almost same. This motion is to put down his/her hand, therefore, the device s motion might be a little faster than the subject by the influence of the gravitation of the device s arm. From this result, it has to deaccelerate the angle velocity of the device while putting down the arm against the gravitation. Deltoid, Middle 3Deltoid, Posterior 6Triceps Brachii, Lateral Head Deltoid, Anterior 4Pectoralis Major Biceps Brachii 7Brachioradialis Fig. Measured s. Measurement of Cerebral Activity with NIRS while ADL Rehabilitation Finally, we suggest the usage of this apparatus to utilize as an assistance device for upper limb s Neuro-Rehabilitation. To confirm the ability of the effectiveness for rehabilitation, it is important to recognize the distribution of the cerebral activity of the users. Especially, if the user s brain activates the areas not only Prefrontal cortex (here after PFC), the effectiveness for rehabilitation is practically naught. Therefore, it is necessary to measure the influence for other areas; Pre motor area (PMA), Supplementary motor area (SMA), Primary motor cortex (PMC), and Primary somatosensory cortex (PSC). To verify the effectiveness of our developed device for Neuro-Rehabilitation, we measured the differences of the cerebral activity while ADL rehabilitation using the device or without the device, and the influence the difference of the device s operator with a near-infrared spectroscopy (NIRS) and compared. We used ETG-4000 (Hitachi Medical Corporation) and measured the variation of Oxy-Hb with 44 probes at tetragonal intervals of 3 [mm]. The measured areas are PFC (associated with consideration), PMA (associated with generate motion with sense), SMA (associated with generate motion with memory), PMC (associated with the output signal of motion), and PSC (associated with the received signal of somatesthesia) as shown in Fig. 7. The experimental block design is as follows: {Rest (Pre) 0[sec], Task 40 [sec], Rest (Post) 40 [sec]}* sets. Each item of six tasks is shown in Table. In Task, the subjects behaved the typical rehabilitation motions (flexion and extension of the elbow) without attaching the apparatus, and they moved by themselves in exact timing according to the instructor s motion. Task is rotation of the elbow by themselves. Task 3 is flexion and extension of 0

11 Journal of Advanced Mechanical Design, Systems, and Manufacturing, Vol.8, No. (04) %MVC 0 Deltoid, Middle 3Deltoid, Posterior 6Triceps Brachii, Lateral Head Deltoid, Anterior 4Pectoralis Major Biceps Brachii 7Brachioradialis w/o device with device (.7 [rad/sec]) with device (0. [rad/sec]) 0 %MVC Deltoid Deltoid Deltoid Pectoralis Biceps Triceps Brachii Brachioradialis, Anterior, Middle, Posterior Major Brachii Lateral Head (a) During the motions of to Deltoid, Middle Deltoid, Anterior 3Deltoid, Posterior 4Pectoralis Major Biceps Brachii 6Triceps Brachii, Lateral Head 7Brachioradialis w/o device with device (.7 [rad/sec]) with device (0. [rad/sec]) 0 0 Deltoid, Anterior Deltoid Deltoid Pectoralis Biceps Triceps Brachii Brachioradialis,, Major Brachii Middle Posterior Lateral Head (b) During the motions of to 3 %MVC 0 Deltoid, Middle 3Deltoid, Posterior 6Triceps Brachii, Lateral Head Deltoid, Anterior 4Pectoralis Major Biceps Brachii 7Brachioradialis w/o device with device (.7 [rad/sec]) with device (0. [rad/sec]) 0 0 Deltoid, Anterior Deltoid, Middle 3 Deltoid, Posterior 4 Pectoralis Major Biceps Brachii 6 7 Triceps Brachii Brachioradialis Lateral Head (c) During the motions of 3 to Fig. 6 Comparison of the %MVC while drinking motion

12 Journal of Advanced Mechanical Design, Systems, and Manufacturing, Vol.8, No. (04) the elbow with assistance apparatus operated by a third party. Task 4 is rotation of the elbow with assistance apparatus operated by a third party. Task is flexion and extension of the elbow with assistance apparatus self operated. Task 6 is rotation of the elbow with assistance apparatus self operated. Each task was carried out five times respectively and averaged. Each measured data was processed as the baseline, which was connected mean data while 0-0 [sec] and [sec]. Furthermore, to compare each area and subject, Effect size was calculated by using Eq. (4). Effect Size = (Rmean - Nmean) / NSD, (4) where Rmean [mmmm] is the mean data of each task, Nmean [mmmm] is the mean data of Task, NSD [mmmm] is the standard deviation of the Rest of Task. Subjects are six able bodied men (age: from to 4). The upper apparatus are fixed to a wheel chair as shown in Fig. 8. The method of measurement was same as the experiment of walking. The rehabilitation target was right arm, and left hand used only operating the suit in Tasks and 6 with a sensor glove by bending fingers. The rehabilitation motions of the arm were determined as shown in Fig. 9. (a) flexion and extension of the elbow by 0-80 [deg], (b) rotation of the subject s elbow (flexion and extension of the elbow by [deg], flexion and extension of the shoulder by -60 [deg], adduction and abduction of the shoulder by 0-40[deg]), there are common motions for ADL rehabilitation. As an actual training, subjects took by -0 [sec] per one motion, and repeated by the signal of the stop. As the basis for the result of Task, mean results of each Task are shown in Fig. 0. The result of Task was activated in all areas, because rotation motion is more complex than only flexion and extension motions. And in the areas PMA and PMC left area s activity was higher than each right area. Because subjects actuated their right arms, however, each right area was activated even though their left arms were not used. The results of Tasks 3 and 4 were inactivated, because subjects depended on the apparatus for his motion. Especially, the result of Task 4 was lower than the result of Task 3. The ratio of the dependence on the apparatus increases according to the complexity of the motion. However, the result of Task was the lowest in all results. The motion of Task is easier than Task 6, and they are able bodied persons, they can easily move their arms as well as self operated apparatus whose moving interval and timing can be determined themselves. Therefore they can behave more comfortably than Task 3. On the contrary, the result of Task 6 was higher than Tasks 4 and. Even though the subjects were assisted with the apparatus, by operating themselves for relatively complex motion, there is a possibility that the subjects try to enhance their cognitive faculty actively and they can have the motivation. As a future work, we will carried out this experiment by patients and verify the consideration. Irradiated position Received position Fig. 7 Configuration of each probe

13 Journal of Advanced Mechanical Design, Systems, and Manufacturing, Vol.8, No. (04) Apparatus (For right arm) Probe ETG-4000 Wheel chair Fig. 8 Component devices of the experiment for ADL rehabilitation Left hand: Sensor glove (a) Flexion and extension of the elbow ( sec/photo) Task No. (b) Rotation of the elbow (3 sec/photo) Fig. 9 Motions of the arm for ADL rehabilitation Table Task Items for ADL Rehabilitation Targeted joint of the right arm Assist Operator for rehabilitation None Elbow None Shoulder and elbow 3 Yes Third party Elbow 4 Yes Third party Shoulder and elbow Yes Subject Elbow 6 Yes Subject Shoulder and elbow 3

14 Journal of Advanced Mechanical Design, Systems, and Manufacturing, Vol.8, No. (04) Oxy-Hb Level PFC PMAl SMA PMAr PMCl PSCl PMCr PSCr -3-4 No. No. 3 No. 4 No. No. 6 Fig. 0 Results of mean data of each task for ADL rehabilitation (six subjects) 6. Conclusions The assistance apparatus for upper limbs to use the patients who cannot lift up their own arm was developed. The shape of the arm is so simple because of taking into account the usability, and it can choose various input devices according to the condition of the users. To confirm the effectiveness of the apparatus for the motion of eating, the activity while using was measured. By using this apparatus, the result of %MVC decreased up to by 60% of the result without using the apparatus. Therefore, the apparatus fulfills the ability for the usage as the tool of the ADL assistance. Furthermore, the cerebral activity was measured while using the apparatus as an upper limb s rehabilitation tool. From the comparison result of the measured data, it is important for Neuro-Rehabilitation to input the user s target motion him/herself. Acknowledgements The experiments of this paper were cooperated by Tatsuya AKIYAMA, Daisuke TSUNODA, Jun SETOGUCHI, Takashi MORI, Ayato IIZUKA and Kenta KOYANO. References Advanced Industrial Science and Technology (AIST), Robotic arm for persons with upper-limb disabilities (RAPUD), available from< (accessed on 3 March, 04) hny International Corporation, Portable spring balancer, available from< html>, (accessed on 3 March, 04) Kiguchi, K., Active Exoskeletons for upper-limb motion assist, Journal of Humanoid Robotics, Vol. 4, No. 3, (007), pp Kouchi, M., Mochimaru, M., Iwasawa, H. and Mitani, S., Anthropometric database for Japanese population , Japanese Industrial Standards Center (AIST, MITI), (000). Lucchesi, N., Marcheschi, S., Borelli, L., Salsedo, F., Fontana, M. and Bergamasco, M., An approach to the design of fully actuated body extenders for material handling, 9th IEEE International Symposium on Robot and Human Interactive Communication, Principe di Piemonte-Viareggio, Italy, Sept. -, (00), CD-ROM. Nakamura, R., Saito, H. and Nagasaki, H., Kiso undogaku (Fundamental kinesiology) sixth edition, Ishiyaku Publishers, inc. ISBN , (007), p. 334, 4. 4

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