AN INDEPENDENT ACTIVE TORQUE BALANCER USING A SERVO- CONTROLLED DIFFERENTIAL GEAR TRAIN

This paper proposes a novel concept of active balancer for reducing the input torque fluctuations of mechanisms. A differential gear train is used in this active balancer and one of its two input shafts is driven and controlled by a servomotor. From the structural point of view, it is designed as an independent device that can be assembled and disassembled easily; from the functional point of view, it can minimize the torque fluctuations in a variety of working con-ditions. At first, an exact control function of the servomotor that can totally eliminate the input torque fluctuations of the mechanism is gained by an analytical method; in what follows, an optimization approach is developed to select appropriate control functions for the servomotor to balance the input torque of the working mechanism with consideration of the servomotor’s own input torque minimization; finally, an integrated method is presented for optimizing both the control function of the servomotor and the structure parameters of the differential gear train. Two numerical examples are given to illustrate the design procedure and to show its feasibility