Fig. 9

Overview of the exoskeleton controllers. The control loops of the exoskeleton are given. The actuator controller is a velocity controller of the motor angle θ. The input of this actuator controller comes from the low-level controller: the desired velocity and the velocity feedforward. Both signals use the dynamic model and the model of the spring. The feedforward \(\dot {\boldsymbol {\theta }}_{ff}\) is obtained from Eq. (13-14)