The use of robots in daily life is growing rapidly every day, in various fields. One important robotic application is exoskeleton for walking rehabilitation used by paraplegics, which are required to operate crutches manually. In this study, we theoretically investigate the feasibility of exoskeleton walker with robotic crutches, which is supposed to be used by quadriplegics, who cannot operate crutches. Our analysis focuses on the following: Formulation of the dynamic equations of motion. Computation of the control torques and contact forces required for maintaining no-slip contact. Development of a simulation tool which will enable design of the robots structure and actuation, planning of gait kinematics, and testing different feedback control strategies. The research also focuses on the dynamic analysis of two main stages in the robot`s movement cycle: a) Advancing the swing leg forward while maintaining no slip contact with the rest of the mechanism and b) Throwing the crutches forward in order to maintain another step in the walking cycle. While in the first stage the number of degrees of freedom equals the number of actuators the second stage is under-actuated. The last part of the research focuses on different techniques for achieving under-actuated motion along a desired trajectory.
