A robot system has first and second joint control units that respectively calculate first and second current values to be supplied to first and second motors based on deviations between first and second operation targets for the motors that are input from a higher device and actual operation of output shafts of the motor, and control operation of the output shafts by supplying current to the motors based on the current values, and an error estimation unit estimating an error in operation of a second joint due to bending and/or twisting of a robot arm based on the first current value and the actual operation of the output shaft of the first motor, in which the second joint control unit calculates the second current value to control the rotation angle of the output shaft of the second motor in a manner compensating for an angle error of the second joint.

A robot system has first and second joint control units that respectively calculate first and second current values to be supplied to first and second motors based on deviations between first and second operation targets for the motors that are input from a higher device and actual operation of output shafts of the motor, and control operation of the output shafts by supplying current to the motors based on the current values, and an error estimation unit estimating an error in operation of a second joint due to bending and/or twisting of a robot arm based on the first current value and the actual operation of the output shaft of the first motor, in which the second joint control unit calculates the second current value to control the rotation angle of the output shaft of the second motor in a manner compensating for an angle error of the second joint.

A computer controlled machining system is provided, and includes a multi-axis machining device that is configured to produce a workpiece based on a part print, which outlines nominal dimensions for the workpiece. A dimensional measuring device is configured to take or determine measured dimensions of the workpiece. A compensation processor is configured to take the measured dimensions from the dimensional measuring device and compare them to the nominal dimensions, and to determine a plurality of deviation sets from such comparison. The compensation processor transfers the deviation sets to the multi-axis machining device, which shifts a machine coordinate system based on the deviation sets.

A numerical control apparatus that controls a machine tool including a plurality of linear axes and rotation axes, and controls a relative tool posture with respect to work on a table includes a program reading unit that sequentially reads a tool posture with respect to the work from a machining program, a determining unit that determines whether the read tool posture is within a predetermined tool posture range, a tool-posture control unit that determines control content of the tool posture according to the determination by the determining unit, and an interpolation/acceleration and deceleration processing unit that controls the linear and rotation axes according to the control content of the tool posture. When the read tool posture is within the predetermined range, the tool-posture control unit determines rotation axis angles of the rotation axes such that a change of tool posture from the last tool posture is limited.