外骨格型動力下肢装具の制御(2部人工の手足)

概要

論文の詳細を見る
This paper describes the control of an active exoskeleton for the lower limbs, which is a kind of motorized orthosis for the locomotor handicapped such as paraplegics. This active exoskeleton supports the body of the patient and has electrohydraulic servo actuators to motorize his or her hip and knee joints. Foot switch sensors and ultrasonic sensors are introduced in this locomotor system to furnish the sole contact signal and the angle of the body of the vertical axis. A microcomputer with special hardware controls thus constitutes the active exoskeleton. In order to generate a gait pattern, a normal pattern taken from a normal subject is prerecorded. However, the frequency characteristic of the active exoskeleton is not sufficient to track the normal gait pattern. To improve the trackability based on the periodicity of the pattern, the input signal is regulated so that the output pattern of the active exoskeleton may be as similar to the normal gait pattern as possible. This new input signal is used at the next gait cycle, and the output gait pattern asymptotically approaches the normal one with walking. Experimental results show that this method is useful as long as the normal gait pattern is periodical. A control method for stable gait is presented by using a 5-link model where there is no torque at the ankle joint. A normalized gait pattern is composed based on normal human gait. The modification for an asymptotical stable gait depends on three state variables of the active exoskeleton: ratio of play back time to a step period, angle, and angular speed of the center of gravity. Using the three state variables, a three-dimensional table for the gait stability is obtained by computer simulation. The normalized gait pattern is modified in amplitude and playback speed according to the parameters indicated in this table. The special hardware preforms the pattern modification to improve the processing time sending it to the servo system. To make certain of the stance phase, the playback start for this phase pattern is synchronized with the heel contact of the corresponding foot. When the swing phase is performed, the controller verifies whether the foot in that phase strikes the ground or not. If heel contact is not made, the gait pattern for the next phase is inhibited. In consequence, there is no danger of flexion of the knee during the support phase. Experimental results with a normal subject show the feasibility of asymptotically stable motorized level walking although control is assured only in the sagittal plane.
バイオメカニズム学会の論文
1984-04-25

外骨格型動力下肢装具の制御(2部人工の手足)

スポンサーリンク

概要

著者

関連論文

スポンサーリンク

外骨格型動力下肢装具の制御(2部 人工の手足)

スポンサーリンク

概要

著者

関連論文

スポンサーリンク

外骨格型動力下肢装具の制御(2部人工の手足)