摘要 |
<p>A method and apparatus for controlling, in power failure, such a machine that a workpiece and a tool are required to be always synchronized in their motion. The method and apparatus allow the tool and workpiece to move back and stop at a safe area without causing any damage to them when the main power source is lost. When a power failure has happened in the middle of a synchronous operation of the motors (S1), a power regeneration function is first disabled (S2). Then a braking control command is issued so as to decelerate the tool drive motor and the workpiece drive motor while maintaining their synchronization (S3). In this step S3, the deceleration rate is controlled so that the motors regenerates energy just enough for driving the tool feed motor. The tool retracts back to an area where it is no longer engaged with the workpiece, by driving the tool feed motor with the regenerative energy produced by the deceleration of the tool drive motor and the workpiece drive motor (S4). <IMAGE></p> |