Mechatronic design and control of a critical biped robot joint

This article presents the mechanical design, hardware architecture and control scheme for critic joints in biped robots. A dynamic simulator was developed in order to quantify torque and currents motor requirements for different gait trajectories. The particular characteristics of biped robots has led to an important design effort in transmission systems, which is deeply discussed before presenting our choice. A specific electronic architecture has been proposed in order to provide the maximum accuracy in trajectory tracking for critic joints. Thus, an absolute encoder located at the output shaft will provide, through the CAN bus, the necessary information to properly correct the joint reference from the global stabilizer. A model-free approach and a Smith predictor on the loop are combined to deal with the transmission uncertainty and the network delays, respectively.