Trajectory control device

Abstract

A trajectory control device for controlling the trajectory of a movable portion by simultaneously controlling the motors of a plurality of movable axes comprises: a servo system response trajectory calculation unit (1) for calculating a servo system response trajectory on the basis of the position commands for the respective movable axes; a shape feature determination unit (9) for, on the basis of whether a command route shape is a straight or curved line from the position commands, outputting a shape feature amount including information about movement directions at the position of a boundary point of the route shape and in the vicinity of the boundary point; a position vector correction unit (2) for correcting a position vector on the basis of the position commands, the servo system response trajectory, and the shape feature amount and outputting the corrected position commands; and servo control units (7, 8) for controlling the motors of the respective movable axes by outputting the motor driving torques so that the positions of the respective movable axes follow the corrected position commands. This makes it possible to perform corrections for suppressing a trajectory error to a sufficiently small level, including even at a place, such as a boundary portion between a straight line and a curved line, where the magnitude and direction of the trajectory error change transiently.

Description

technical field [0001] The present invention relates to a trajectory control device for managing tool trajectories in an NC control device for controlling NC machine tools, NC laser processing machines, etc., and particularly relates to a trajectory control device for suppressing trajectory errors and realizing high-speed and high-precision machining regardless of the shape of a command path . Background technique [0002] When processing is performed using a machine such as an NC machine tool or an NC laser processing machine, the position of the tool (blade such as an end mill) relative to the workpiece is controlled so that it follows a commanded path. This control is called trajectory control, and is generally performed by performing servo control so that the actual position of each movable axis of the machine follows the position command of each movable axis obtained from the command path. [0003] As a problem in trajectory control, there has been a conventional probl...

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Problems solved by technology

[0007] However, in the method disclosed in the above-mentioned Patent Document 1, although the trajectory error can be effectively corrected when the same amount of trajectory error is stably generated as in a simple circle or an arc, when switching from a straight line to an arc In the case of such a command path, there is a problem that the trajectory error cannot be sufficiently corrected at the boundary portion, and the trajectory error remains in the corrected movement path.

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