Abstract: A moving component of a robot, such as a robot arm, is controlled to return from a given position to an original point after the moving component has traced paths established respectively by a group of successive motion data blocks including positional data representative of positions of the moving component. The moving component is moved on the basis of positional data in one of the motion data blocks which precedes a present position of the moving component, and then is moved on the basis of positional data in one of the motion data blocks which precedes said first-mentioned one of the motion data blocks. Therefore, the moving component is moved successively backwards along the paths based on the positional data in the motion data blocks.

Abstract: A machining unit for use in a machine tool comprises a slide base support mounted on a base of the machine tool, a slide base located above the slide base support, and a device slidably mounted on the slide base for working a workpiece. Link members are pivotably attached to the slide base support and the slide base to constitute a quadric link mechanism. The quadric link mechanism is operated by a hydraulic cylinder-piston assembly swingably secured to the slide base support. The machining unit may further comprise a member attached to the slide base support for positioning and supporting the slide base so as to maintain a predetermined inclination thereof with respect to the horizontal.