Design and Dynamic Analysis of a Two-Degree-of-Freedom Pneumatic-Electromagnetic Hybrid Actuator Using Bellows Pneumatic Actuator

Various actuators have been developed to improve the performance of cooperative robots. Multi-degree-of-freedom (multi-DOF) electromagnetic actuators can rotate multi-DOF by a direct drive and can contribute to system miniaturization and higher precision. However, the biggest challenge is to increase the output because the torque cannot be amplified using a reduction gear. To solve this problem, this paper focuses on a hybrid actuation with a pneumatic actuator, which has a large output density. In this study, we propose a two-DOF pneumatic-electromagnetic hybrid actuator that integrates a bellows pneumatic actuator and a two-DOF electromagnetic actuator. First, the concept, design, and operating principle are presented. Next, the torque control method, dynamic model, and attitude control system are shown. In the torque analysis, the maximum torque of the proposed actuator is four times larger compared with a conventional two-DOF electromagnetic actuator of the same size. The dynamic simulation results show that attitude control is possible with hybrid actuation. Based on the results, a hybrid multi-DOF actuator using multiple drive sources is proposed for the first time.