Analysis of Sit–to–Walk Movement with an Admittance Controlled Robotic Walker

In this study, we identify the effects of dynamic characteristics of the robotic walker on the muscle activities and operating forces of the young healthy subjects in sit-to-walk (STW) movement. The experiment was performed under a total of eight conditions where the dynamic characteristics, inertia, damping, and frictional force were changed in the STW movement. We analyzed the effect of the dynamic characteristics of the robotic walker on the muscle activity and operating force of the upper and lower limb muscle groups in the STW movement by multiple regression analysis. From the experimental results, it is revealed that the inertia of the robotic walker can change the load on the user's vastus lateralis and tibialis anterior muscle in the standing movement under the condition that friction is applied as a load, and the effect of the friction force of the robotic walker on the operation force is clarified from the viewpoint of walking stability of the user. Furthermore, we clarify that the damping and friction of the robotic walker can change the load on the user's rectus femoris, tibialis anterior, and gastrocnemius muscle in the transition phase from the standing movement to the walking movement.