Eiichirou Tanaka

Development of closed-fitting-type walking assistance device for legs and evaluation of muscle activity

A walking assistance device using a flexible shaft was developed. The combination of a flexible shaft with a worm gear was successfully adopted on this device to simplify its appearance and reduce its size. A hybrid — control system on this device controls both torque and angle at the ankle and knee joints. In this system, the torsional spring constant of the flexible shaft is taken into account by the motor in controlling the power and angle of rotation of the motor. To expand the area in which a person may use the device, it is equipped with a self-contained system powered by a Lithium-ion battery and controlled by an SH-4 microcomputer and actuators, consisting of motors and gears, all of which are carried in a small backpack. Consequently, persons using the device may walk freely in both indoor and outdoor environments.

Walking assistance apparatus using a spatial parallel link mechanism and a weight bearing lift

A prototype for a walking assistance apparatus for the elderly or motor palsy patients was developed as a next-generation vehicle or movable neuro-rehabilitation training appliance, using a novel spatial parallel link mechanism and a bearing lift. The flat steps of the apparatus move in parallel with the ground; the apparatus can support entire leg alignment (including soles) and assist; walking behavior at ankle, knee and hip joints simultaneously. In order to respond the variation of equipped persons walking velocity, the length of stride and walking cycle while walking with wearing the apparatus were compensated by using the relation of walking ratio. Therefore the apparatus can be controlled in response to equipped persons will. Motor palsy and muscle weakness patients can walk by themselves by using the apparatus; patients who have ambulation difficulty can use the apparatus with weight bearing lift that we developed. Using the apparatus with the weight bearing lift prevents stumbling and enables input of walking movement to the brain motor area. It is very effective for rehabilitation to use the apparatus with the weight bearing lift. This newly developed system facilitates motor palsy and muscle weakness patients in the rehabilitation program.

Gait and ADL rehabilitation using a whole body motion support type mobile suit evaluated by cerebral activity

We developed a new whole body motion support type mobile suit. This suit can be used separately for supporting the upper and/or lower limbs, for assisting ADL (Activities of Daily Living). We also developed a mobile lifter system which can bear both the equipped person and the suit. This suit and the lifter can be used by motor palsy patients suffering from stroke, spinal-cord-injury, and central nerve disorders. Using this device, these patients can recover normal gait with no risk of falling. In this paper, the cerebral activity during walking using the suit and normal gait without the suit are compared. According to multiple trials with the suit on a treadmill, the activities of the premotor area sensory motor cortex decreased. Especially, while walking using the suit for supporting lower limbs without swinging arms, the cerebral activities of most of the areas decreased. It means to be ineffective for the patients accustomed to the suit in rehabilitation. However, on the contrary, by walking while swinging bilateral arms (even though these arms were assisted by the suit), the activity in the supplementary motor area increased (this area of the brain is related with memory of motion). Furthermore, the cerebral activities while walking on a treadmill and while walking in a corridor with an outside view were compared. From the results of this experiment, we found it is most effective for gait training to actually walk and not stay fixed in one location. We also found it is important for patients to swing their arms during gait training in rehabilitation. Finally, we compared the differences of the cerebral activity during ADL rehabilitation (flexion, extension, and rotation of the subjects elbow) using our suit operated by a third party or themselves (using opposite hand). From this result, cerebral activity while self operated was higher than the result operated by third party, even though the subjects were assisted with the suit in both experiments. From these trials, we can conclude that this suit is suitable to assist patients in gait and ADL rehabilitation.

Development of a walking assistance apparatus using a spatial parallel link mechanism and evaluation of muscle activity

A prototype for a walking assistance apparatus for the elderly or motor palsy patients was developed, using a novel spatial parallel link mechanism. The flat steps of the apparatus move in parallel with the ground; the apparatus can support entire leg alignment (including soles) and assist; walking behavior at ankle, knee and hip joints simultaneously. By using a flexible link, constructed of stainless steel and rubber, the apparatus can realize the natural twisting motions of the ankle. Furthermore, in order to assist walking on uneven surfaces, we investigated walking on a slopes or stairs. For these tasks, the apparatus was equipped with a gyro sensor and an ultrasonic sensor; so the angle of the slope and the height of the stairs could be recognized. The apparatus adapted according to the signals from these sensors. Results owed that our experiment, the equipped person wearing the apparatus could walk on slopes and stairs. Motor palsy and muscle weakness patients can walk by themselves by using the apparatus; patients who have ambulation difficulty can use the apparatus with weight bearing lift that we developed. Using the apparatus with the weight bearing lift prevents stumbling and enables input of walking movement to the brain motor area. It may be beneficial for rehabilitation to use the apparatus with the weight bearing lift. This newly developed system may facilitate motor palsy and muscle weakness patients in the rehabilitation program. The effectiveness of the apparatus for one hour walking was evaluated by variation of Mean Power Frequency (MPF) of the Electromyography (EMG) data with continuous wavelet analysis. Muscle fatigue of the Tibialis Anterior muscle (TA) decreased during wearing of the apparatus. We showed the effectiveness of using the apparatus in walking.

Motion assistance apparatus enabled for neuro-rehabilitation of patients and for the promotion of exercise for the elderly

We developed a motion assistance apparatus which can be used for neuro-rehabilitation of patients and for the promotion of exercise for the elderly. This apparatus assists only the ankle joints of the equipped person according to the posture of him/her while walking, getting up, sitting, and standing. By using this apparatus, the dorsiflexion and plantarflexion of the ankle joint of the equipped person can increase while walking. Therefore, this apparatus can prevent stumbling and promote walking and various motions.

A walking promotion method using the tuning of a beat sound based on a two-dimensional emotion map

We proposed a method that promotes walking which uses a two-dimensional emotion map. In this method, a subject listened to a beat sound while walking. The beat was adjusted according to the condition of the subject, based on his/her comfortable walking frequency. Simultaneously, the walking velocity, the stride length, and the heart beat of the subject while walking was measured, and LF/HF was calculated from the result of measured heart beat. Furthermore, we asked them to give information on the condition of their feelings, from pleasant or not by 5 levels in each case of the beat sound. By using these data, a two-dimensional walking condition map and two-dimensional emotion map were made and we found the relation between these two maps. Therefore, according to the emotional condition of the targeted person while walking, this method can promote or restrain walking adequately, only adjusting the beat sound.

Development of a walking assistance apparatus for gait training and promotion of exercise

We developed a walking assistance apparatus which can be used for gait training of neuro-rehabilitation for patients and for the promotion of exercise for the elderly. This apparatus assists only the ankle joints of the equipped person according to the posture of him/her while not only walking, but also getting up, sitting, and standing. By using this apparatus, the dorsiflexion and plantarflexion of the ankle joint of the equipped person can increase while walking. This apparatus can improve of the equipped persons gait.

Development of a control method of a walking assistance apparatus for the elderly or rehabilitants

A prototype for a walking assistance apparatus for the elderly or rehabilitants of motor palsy patients was developed as a next-generation vehicle or movable neuro-rehabilitation training appliance, using a novel spatial parallel link mechanism and a bearing lift. The flat steps of the apparatus move in parallel with the ground; the apparatus can support entire leg alignment (including soles) and assist; walking behavior at ankle, knee and hip joints simultaneously. To respond to the variation of equipped person’s walking velocity, the length of stride and walking cycle while walking with wearing the apparatus were compensated by using walking ratio. Therefore the apparatus can be controlled in response to equipped person’s will. Next, we developed a control method of the apparatus by using impedance control, taking into account the dynamics of the apparatus and the legs of an equipped person, and assist ratio for the equipped person. By adjusting the value of natural angular frequency of the desired dynamic equation for the equipped person, this apparatus can assist walking according to the equipped person’s desired response of the apparatus. Furthermore, motor palsy and muscle weakness patients can walk by themselves by using the apparatus; patients who have ambulation difficulty can use the apparatus with weight bearing lift that we developed. Using the apparatus with the weight bearing lift prevents stumbling and enables input of walking movement to the brain motor area. From the results of measured %MVC, the validity of the weight bearing lift was shown.Copyright

Study on the walking support machine indoors by assisting whole legs

There is currently research to support the construction of a walking assist machine, which machine uses a spatial parallel link mechanism for the elderly or rehabilitants. The flat steps of the assist machine move in parallel with the ground and can support the legs of a person including the soles. We developed a prototype and designed to assist people walking at up to fifty percent power. To grasp the walking phase of each leg of the equipped person, pressure sensors were laid under the thenar eminence and the heel of the sole, and the pressure variation at each sensing point was measured. For safety support, we developed a control method of the walking assist machine to fit the motion in phase by phase. Furthermore, in order to support walking indoors, we investigated the assist methods of turning around during walking and walking on a slope or stairs. A flexible link was installed in the mechanism for taking into account the twisting motions of the waist and ankle. To grasp the behavior of turning around during walking of the equipped person, pressure sensors were attached outside of the flexible link in both crural parts of the machine. As a result of the experiment wearing the machine, the equipped person could turn around during walking at will. To confirm the validity of the supporting method, muscle activity of the leg while wearing the walking assist machine evaluated by using the surface electromyography (called as “EMG”), and calculated the ratio of the integrated EMG (called as “IEMG”) with and without the walking assist machine. The initial results show that the activities of the rectus femoris muscle and the tibialis anterior muscle can be held to approximately 60 percent by wearing the walking assist machine. Furthermore, in order to support walking indoors, we investigated the assist methods of walking on a slope or stairs. The machine was equipped with a gyro sensor and an ultrasonic sensor; the angle of the slope and the size of stairs could recognize and the machine could be controled according to the signals from the sensors. As a result of the experiment wearing the machine, the equipped person could walk on a slope or stairs at will. The subject assisted with the machine was able to walk on a slope up to the angle of plus or minus fifteen degrees.Copyright

Study of RE-Gait® as the Device That Promotes Walking Using a Two-Dimensional Emotion Map

We developed a walking assistance apparatus RE-Gait® for not only the elderly but also apoplexy patients, which assist the ankle joint of the equipped person. By only assisting the ankle joint, the equipped person’s leg can be raised. To keep up the user’s motivation for exercise using this apparatus, it is necessary to assist not only physically but also mentally. Therefore we suggested the new method of promotion walking, using the walking assistance apparatus while listening to the beat sound, which was adjusted according to a two-dimensional emotion map. In this paper, the relation between emotion map and walking condition map is shown.