Coordination of the Biarticular Actuators Based on Mechanical Output Power in an Explosive Jump Experiment

Abstract

The natural actuation redundancy of the human leg is partly due to the existence of biarticular muscles. These muscles span two joints, bringing in substantial advantages for human locomotion. The physiological evidence suggests that the biarticular muscles can reduce the negative power production in the actuators and therefore contribute to the efficiency of the explosive movements. We perform the jump movement on the compliant robotic leg (CARL) to verify the role of biarticular elements in a physical platform. We further investigate how the actuator force distribution method can contribute to the economics of the explosive task. In our experiments, the biarticular actuators display similar behavior to their biological counterparts, with respect to energy transfer. A comparison study of two force distribution methods shows that the minimization of the instant power can improve the efficiency of the movements by up to 5%. It is demonstrated that the deployment of the redundant biarticular actuators with instant power minimization criteria can increase the efficiency of the jump motion with up to 11%, compared to the configuration with no actuation redundancy.