When performing work on a workpiece with a tool of a robot while the robot and the workpiece are moved relative to each other by an additional axis mechanism, the tool is to be pressed against the workpiece from an appropriate direction. A control device includes an additional axis movement amount acquisition section that acquires an additional axis movement amount, a command generation section that generates a movement command for a robot based on operation plan data of the robot and the additional axis movement amount, a vector acquisition section that, based on the operation plan data or the additional axis movement amount, acquires a vector in a direction along a work target portion of a workpiece, and a pressing direction determination section that determines a pressing direction in which the robot is to press the tool against the workpiece during work, using the vector acquired by the vector acquisition section.

A robot machining system including: a robot in which a hand is attached to a distal end of an arm thereof; a force sensor provided in one of the robot and the machining device and detecting a force acting therebetween when a workpiece is being machined; and a control device that controls the robot or the machining device according to the detected force, wherein one of the machining device and the hand is provided with guide surfaces that extend along a direction in which the machining device and the hand are relatively moved when the workpiece is machined; the other of the machining device and the hand is provided with guided portions that are brought into contact with the guide surfaces when the workpiece is machined; and the control device performs control for maintaining a contact state between the guide surfaces and the guided portions during machining of the workpiece.

A robot machining system including: a robot in which a hand is attached to a distal end of an arm thereof; a force sensor provided in one of the robot and the machining device and detecting a force acting therebetween when a workpiece is being machined; and a control device that controls the robot or the machining device according to the detected force, wherein one of the machining device and the hand is provided with guide surfaces that extend along a direction in which the machining device and the hand are relatively moved when the workpiece is machined; the other of the machining device and the hand is provided with guided portions that are brought into contact with the guide surfaces when the workpiece is machined; and the control device performs control for maintaining a contact state between the guide surfaces and the guided portions during machining of the workpiece.