Path tracking control considering center of gravity shift and load change for an omni-directional walker

Abstract

Walking is a vital exercise that is very important for health and everyday life. In the authors' previous studies, an omni-directional walker was developed for walking rehabilitation. Walking training programs are stored in the walker so that rehabilitation can be carried out without a physical therapist. However, the walker sometimes strays from the predefined path due to a center of gravity shift and load change. It is necessary for the walker to precisely follow the paths defined in the walking training programs to guarantee the effectiveness of rehabilitation and the user's safety. Therefore, this paper describes the path tracking control of the omnidirectional walker during the center of gravity shift and load change. First, the kinetics of the omni-directional walker motion is presented. Second, an adaptive control strategy is proposed. Finally, path tracking simulations are carried out using the proposed method. The simulation results demonstrate the feasibility and effectiveness of the adaptive control method.

Improvement model for omnidirectional rehabilitative training walker and tracking control

“…So the motors provided the same force when the different weight patients trained using the walker. Adaptive control method for the omnidirectional walker is discussed in [11][12][13], the kinetics equation was improved by considering the centerof-gravity shifts and load changes caused by users. The adaptive controller had obtained favourable tracking effect.…”

Redundant Input Safety Tracking for Omnidirectional Rehabilitative Training Walker with Control Constraints

“…To operate effectively in real‐world applications, the control algorithm must guarantee that these actuators can follow a prescribed path accurately. Note that all existing results were obtained under the assumption that the actuator motors are fault‐free for rehabilitative robots . However, in practical applications, actuator failures and saturation are often unavoidable.…”

Robust Redundant Input Reliable Tracking Control for Omnidirectional Rehabilitative Training Walker

“…It was found that tracking neglects the mass and inertia matrix when the loads are overweight, and consequently tracking precision is reduced. An adaptive control method for the ODW was discussed in [6][7][8]. The kinetic equation was improved by considering the center of gravity shifts and load fluctuations caused by users.…”