Optimal gait design for the lower extremity exoskeleton (Exoped)

Assistive robots have been grown in recent years and joints’ moving pattern is one of the important issues in these robots. The predefined trajectory for the robot brings some stability difficulties for the users. This paper introduces a systematic way to produce an optimal gait for the controller of the lower extremity exoskeleton. This optimal gait producing strategy releases us from the exhausting procedure of walking pattern capture in different paces which requires various devices and motion analysis lab. A feedback-controlled system is defined which enables us to change walking parameters during steps with a smooth walking pattern which is of vital importance for the patients in these kinds of robots. This goal has been achieved by solving an optimal control problem, and the cost function of this optimization problem is obtained thorough walking limitations. Implementation on the Exoped robot verifies the performance of the proposed walking trajectory planning method in this paper.

I. Introduction

Precise and powerful controlling approaches has encouraged engineers to develop assistive robots for different purposes [1]. The most important motives to develop wearable robotics specially exoskeletons were helping disabled or elderly people to move and for military use. Besides, these robots have been used in medical centers to improve the treatment of patients such as spinal cord injury [2] or gait rehabilitation [3], [4].