Control Motion of A Human Arm: A Simulation Study

This article presents a simulation study to control a human arm motion using muscle excitations as inputs. Our simulation implements the musculoskeletal model Arm26 provided in OpenSim which has 2 DOF and 6 muscles as actuators. First, in order to drive the limbs’ motion to track a desired trajectory, we propose an Adaptive Sliding Mode Controller (ASMC) to compute the necessary driving moments at each joint. Since the system is over actuated, the Generalized Reduced Gradient (GRG) method is implemented to optimally distribute forces to each muscle. Because the system has a cascade structure, another Sliding Mode Control (SMC) within a Back Stepping algorithm framework is used to drive the muscle excitation so that each muscle can produce the desired force.