Controller for machine

A controller for controlling a machine having drive axes driven by servomotors in accordance with an operation program prepared as data in a rectangular coordinate system, comprising:

• a command analysis section for analyzing commands of the operation program to output data for first interpolation processing;
• first interpolation means for performing first interpolation processing on the data outputted from said command analysis section to obtain a first interpolated position on a motion path in the rectangular coordinate system at every first sampling period;
• a transformation section for transforming the first interpolated position in the rectangular coordinate system into positions of the drive axes in a coordinate system of the drive axes;
• a memory for temporarily storing the transformed positions of the drive axes;
• a composite tangential acceleration calculating section for obtaining a composite tangential acceleration in the coordinate system of the drive axes for each of segments between the first interpolated positions based on the transformed positions of the drive axes and maximum allowable acceleration values preset for the drive axes;
• a composite velocity limit calculating section for determining a composite velocity limit in the coordinate system of the drive axes at an end point of each of the segments;
• a composite deceleration target velocity calculating section for determining a composite deceleration target velocity in the coordinate system of the drive axes at the end point of each of the segments in accordance with the composite tangential acceleration and the composite velocity limit;
• acceleration/deceleration control means for performing acceleration/deceleration control for a composite tangential velocity of the drive axes in accordance with the composite deceleration target velocity to obtain a composite tangential motion amount at every second sampling period;
• and
• second interpolation means for obtaining a second interpolated position at every second sampling period based on the tangential motion amount determined by said acceleration/deceleration control means and the transformed positions of the drive axes stored in said memory to determine motion commands for the drive axes.