Figure 5
Block diagram of event-driven intermittent feedback control of human quiet standing. On/off switching (SWk) of each muscle (or each group of muscles) is triggered depending on the error between current state y (consisting of angular displacements and velocities) and reference value r. The reference value of r could be set for each muscle or each group of muscles. The intermittent muscle activities generate joint torque and, together with passive torque (stiffness and damping components K and B) without a time delay, control input u to actuate the skeletal system and induce joint fluctuations.
