Abstract: Assistive lower limb exoskeleton robot has been developed to help paraplegic patients walk again. A gait planning method of this robot must be able to plan a gait based on gait parameters, which can be changed during the stride according to human intention or walking conditions. The gait is usually planned in cartesian space, which has shortcomings such as singularities that may occur in inverse kinematics equations, and the angular velocity of the joints cannot be entered into the calculations. Therefore, it is vital to have a gait planning method in the joint space. In this paper, a minimum-time and minimum-jerk planner is proposed for the robot joints. To do so, a third-order system is defined, and the cost function is introduced to minimize the jerk of the joints throughout the stride. The minimum time required is calculated to keep the angular velocity trajectory within the range specified by the motor’s maximum speed. Boundary conditions of the joints are determined to secure backward balance and fulfill gait parameters. Finally, the proposed gait planning method is tested by its implementation on the Exoped? exoskeleton.

Key words:  , Bionic robot , · Gait planning , · Optimization , · Complete paraplegic , · Lower limb exoskeleton