Actuations with motors have provided essential motive forces for robots due to the high continuous power per unit mass and high efficiency of electric motors. However, they have low dexterities and are unsuitable for motions such as sprinting owing to the high transmission ratio of the actuation structure and the poor dynamic performance of the motors, especially the ability to fast reverse periodically. These characteristics are quite essential to elevate the locomotion speeds of robots. To solve the problem and improve the dexterity of actuations, a joint actuation integrated with two multidisc magnetorheological (MR) dampers is designed and evaluated in this study. A novel reversal approach that relies on the MR dampers to change the output rotating direction instead of the motor is adopted in this study to provide fast responses of the output speed and high explosive output torques. As a result of the short reacting time of the MR material, the joint actuation can reverse the output rotational direction at a frequency of up to 40 Hz. A flywheel is attached to the motor to increase the rotational inertia and the kinetic energy of the working motor, thus achieving an explosive output capacity of the joint actuation, which is more than the traditional direct-drive actuating method, through the novel reversal approach in this study. The high dexterity and strong explosive output capacity are supposed to assist in faster locomotion and more powerful explosive force of the robot.

joint actuation,high dexterity,strong explosive output capacity,multidisc magnetorheological damper