Linearized gear drive system via bilateral control based twin-drive mechanism

Gear transmission is a feasible scheme to realize small size and large torque output manipulator. However, the nonlinear factors, especially the backlash and friction, seriously degrade the performance of a gear drive system. This paper proposes a twin-drive gear system to prevent performance degradation from the nonlinear factors. In the proposal, two motors drive the output axis with differential motion. All of the gears and axes in the system rotate in an invariant direction with nonzero velocity, which avoids the appearance of backlash and nonlinear friction. Moreover, new control scheme of the twin-drive gear is proposed based on the idea of bilateral control. This control scheme utilizes the information of velocity and torque in both the two motors. Ideal synchronized motion is achieved between the two motors, which maximizes the performance of the proposed mechanism. The proposal realizes linearized gear transmission compared with traditional single gear drive. Experiments and applications confirm the validity.