| 摘要 |
PURPOSE:To reduce the varying width of a moving velocity by controlling the sweeping direction of a circulation type sweeper and the start/stop of the sweep according to the amplitude of a mechanical arm current. CONSTITUTION:An ultrasonic motor is composed of a circulation type frequency sweeper 1, a phase shifter 2, power amplifiers 3-4, and a sweep controller 6, etc. In this case, a mechanical arm current detector 5 is provided, its detection current is input to the controller 6, which outputs sweep ON/OFF direction command in response to the current. The logic unit of the controller 6 turns ON the command 8 when the current is smaller than a set range, sets a sweeping direction command 7 to a smaller frequency from larger frequency, and set the frequency from small to larger one when it is larger than the set range. Thus, the shifter 2 outputs predetermined AC signal A, B by a driving frequency signal 9, and applies driving signal VA, VB to the electrode A, B of the motor through the amplifiers 3-4. |
