| 摘要 |
PURPOSE:To prevent a robot arm from lowering under the influence of its deadweight by beginning to drive two ultrasonic motors at the time when minute time difference has been generated through a time difference generating circuit in starting the robot arm. CONSTITUTION:Two ultrasonic motors 4a, 4b mounted on the same supporting shaft of a robot arm 1 receive a driving signal sent from a driving signal generating device 8 through a time difference generating circuit 7 in the case of starting the robot arm 1, and severally rotate with about minute time difference to actuate the arm 1. Thus, since a stator and a rotor which are composed in the other ultrasonic motor have been pressed against each other when the one side of the ultrasonic motors begins driving, frictional force functions between the stator and the rotor to prevent the arm 1 from lowering. |
