Patent ID: 8712576

Claim:
A controller for a machine tool that moves relative to a workpiece along three linear axes of x-axis, y-axis and z-axis, and also pivots relatively around a first pivoting axis and a second pivoting axis, wherein the first pivoting axis is a rotating axis parallel to the y-axis, and the second pivoting axis is a rotating axis parallel to the x-axis, said controller for said machine tool comprising; an allowable position error setting member setting an allowable position error between a commanded machining position and an actual machining position; a first velocity control parameter deciding member deciding a first velocity control parameter of said first pivoting axis in accordance with said allowable position error and a first distance of a nose position of a tool from said first pivoting axis, wherein the first distance varies depending on an angle of the first rotating axis, and the nose position of the tool being the actual machining position when the tool touches the workpiece, and wherein the nose position is defined in terms of said x-axis, y-axis and z-axis; a second velocity control parameter deciding member deciding a second velocity control parameter of said second pivoting axis in accordance with said allowable position error and a second distance of the nose position from said second pivoting axis; wherein said second distance is a parallel distance between the second pivoting axis and the x-axis of the nose position, and varies depending on the surface of the workpiece; and a controlling member controlling a velocity of said first and second pivoting axes based on said first and second velocity control parameters; wherein said controller for said machine tool further comprising an allowable angular error calculating member calculating a first allowable angular error of a difference between a commanded angle of said first pivoting axis and an actual angle of said first pivoting axis based on said allowable position error being set and said first distance; and said first velocity control parameter deciding member decides said first velocity control parameter according to said first allowable angular error.