Dynamics Modeling and Performance Analysis of RoboWalk

In this article, after introducing the RoboWalk body weight support assistive device, the forward kinematics of human and the inverse kinematics of the assistive robot are introduced. Then, a method for obtaining an analytical dynamics of the system is presented. This method is based on modeling the human body without modeling its constraints and contact forces. Then, the contact forces are taken into account and mapped into joint space of the robot using the jacobian matrices of interaction points. This method of modeling is then compared and verified by the numerical Recursive Newton Euler Algorithm. Since the numerical method is more efficient and has less computational complexities, it can be used in implementing the control algorithms on the robot. After the model is verified, a control strategy for assisting the user is designed and implemented on the developed model of RoboWalk. The performance of this control strategy is evaluated by comparing the floor reaction force and user joint torques if using Robowalk or not. Finally, the actuator’s specification to fulfill our requirements is discussed.