| 摘要 |
Settling response characteristics after change-over from a speed controller to a position controller is attained. Fluctuations in a time taken until change-over is made from the speed controller to the position controller are reduced to stabilize a moving time and to shorten an access time. To this end, a position controller generates a drive signal of a linear or primary function of time in such a manner that a position deviation signal responds to it with a ternary-order function of time which becomes zero in a desired finite settling time. Further, a feedforward signal generator is provided to reduce a follow-up error to a target position signal as an output of a target position signal generator. Furthermore, a switching judger is provided to start its judging operation after the position deviation signal reaches a predetermine position deviation and to perform switching operation from the speed controller to the position controller when the position deviation signal is not larger than a value corresponding to a proportional multiple of a speed signal.
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