Development of a Novel Rollator Equipped with a Motor-Driven Chest Support Pad and Investigation of its Effectiveness

In recent years, a rapid increase in bedridden elderly, due to cerebral strokes and other diseases, has become a social problem due to soaring medical costs and heavy burden of long term care support. Therefore, development of walk rehabilitation devices for the elderly, suffered from cerebral strokes, is strongly expected. In the research so far, the authors have developed a rollator with a chest support pad that can rotate freely with one degree of freedom, and the effectiveness of its walk assistance was evaluated. In this study, a novel rollator using a motor-driven chest support pad was developed. A compact system to combine data collect system and motor control was configured. Walk measurements for six subjects were conducted using the developed rollator. The relationship between the movements of the lower limbs and rotation of the motor driven chest support pad was investigated. Time series and power spectrum results were analyzed, and the effectiveness of the motor-driven chest support pad on movement of the lower limb during walking was discussed.

Ankle Joint Stretching Device Using Tension Rod for Self Rehabilitation

This paper proposed an ankle joint stretching device that is intended for self-rehabilitation by using a tension rod structure. Physical therapists treat their patients to prevent a subject ankle joint’s contracture and improve walking function. Still a sufficient rehabilitation therapy cannot be done due to demand for a labor-task of the ankle joint rehabilitation. There is a demand for the self-rehabilitation system long time to reduce the labor task, and especially it can be installed easily in a chair or bed in a patient home. By using a pantograph jack and spring casters, the developed device does not depend on installation location. It does not need a transfer assist process to the rehabilitation machine, which causes back pain of caregivers, and it allows for a self-rehabilitation of an ankle joint stretching. The experiment confirmed that the positional relationship was stabilized between the rotation axis of the device and the ankle joint position within (σx,σy)=(2.4, 2.5) mm during ankle dorsiflexion stretching in a fixed state of the device, which was realized by the pantograph jack and spring casters. Our proposed system that does not need transfer assistance before/after treatment will lead to self-rehabilitation for the ankle joint.

Impedance Control Considering Velocity Saturation of a Series Elasticity System with a Motor

Human-machine cooperative robots are required to drive their arms with low impedance and high torque. As a compact mechanism that generates a large torque and has low impedance characteristics, the series elastic drive system, in which an elastic element is inserted between the motor and driving unit, has been proposed. In this paper, we propose a method of applying impedance control to a series elasticity system with a torque-compensating motor that uses a torsion bar as an elastic body that enables its use under high loads. The stability of the system was verified via simulation and experiment by considering the allowable speed and maximum torque of the motor. The experimental results from the conventional system and the proposed system were compared. The proposed system was confirmed to be superior to the conventional system in terms of both stability and tracking performance. Consequently, the effectiveness of our proposed system was confirmed.

Proposal of Wheeled Gait-Training Walker with Dual-Assist Arms and Preliminary Pelvis-Handling Control

To achieve good rehabilitation in a person, the amount of walking by the person must be increased. Herein, a compact wheeled gait-training walker with dual-assist arms for assisting pelvic motion is proposed. The training walker is constructed by modifying a commercial wheeled walker with armrests. Therefore, it can be used easily by patients to perform their daily activities at rehabilitation sites. The hardware system and controller of the proposed assisting arms are designed based on gait-assist motions conducted by a physical therapist. The dual arms can achieve a pelvis-assisting motion with five degrees of freedom. A trajectory-following control with virtual compliance is implemented for the arms. Gait-assisting experiments are conducted, in which the dual arms allow a pelvic-like plate to follow the trajectory of a reference pose while reducing the upper body’s weight resting on the armrests. A 20 N force on the armrests, which represents the upper-limb load, is reduced while the plate follows the trajectory, and the proposed gait-assisting controller is validated.

Experimental Study of Ankle Joint Pushing Mechanism Concerning About the Horizontal Movement of Talus

[abstFig src='/00290002/03.jpg' width='300' text='Proposed ankle joint pushing mechanism for the movement of the talus' ] An ankle joint pushing system that absorbs the horizontal movement of the talus is proposed, and the effects of the horizontal movement absorbing mechanism in the system are examined. The bending of the ankle joint is an important medical treatment that physical therapists (PTs) utilize to help their patients recover their ability to walk and to prevent contracture. However, since the ankle treatment requires a large amount of force (nearly equal to the subject’s weight) plus precise angle and power control, manual treatment by PTs has not been replaced by mechanical treatment systems. In order to realize the mechanization of the ankle joint pushing treatment, the system developed here uses two features. (1) The proposed device fixes the ankle joint position correctly by making contact with the Achilles tendon, the back of the calf, and the hip. (2) The bucket rotation center shifts its position horizontally with the movement of the talus when the foot is pushed back. This mechanism can push the toes or any part of the foot strongly and stably without causing the patient any pain. It can also stretch the biceps femoris and gastrocnemius muscles simultaneously, which could previously only be done by a physical therapist. During 73 N stretching treatment tests done on four subjects, 22.2 mm (S.D. 6.4 mm) horizontal (ventral direction) movements of the ankle joint were observed due to the movement of the talus, and our proposed device mechanism successfully suppressed the movement to a 1.8 mm (S.D. 1.3 mm) horizontal (ventral) movement in the same 73 N stretching treatment.

Study on Presentation System for Walking Training Using High-Performance Shoes

<div class=""abs_img""><img src=""[disp_template_path]/JRM/abst-image/00270006/13.jpg"" width=""300"" /> Proposed walking training system</div>The number of accidental falls has been increasing among the elderly as society has aged. The main factor is a deteriorating center of balance due to declining physical performance. Another major factor is that the elderly tend to have bowlegged walking and their center of gravity position of the body tend to swing from side to side during walking. To find ways to counteract falls among the elderly, we developed walking training system to treat the gap in the center of balance. We also designed High-Performance Shoes that showed the status of a person’s balance while walking. We also produced walk assistance from the insole in which insole stiffness corresponding to human sole distribution could be changed to correct the person’s walking status. We constructed our High-Performances Shoes to detect pressure distribution during walking. Comparing normal sole distribution patterns and corrected ones, we confirmed that our assistance system helped change the user’s posture, thereby reducing falls among the elderly.