Robot with virtual arm positioning based on sensed camera image

A robot numerical control apparatus for controlling the operation of a robot equipped with a camera on one of a plurality of arms thereof for sensing an image, comprising:

• a memory for storing a program wherein instructions for operation of said robot are written;
• a coordinate transformer for transforming coordinate data of a desired displacement position expressed by an orthogonal coordinate system to a coordinate value expressed by an axial coordinate system which represents a positional relationship between mutually adjacent arms and for outputting axial coordinate data;
• a program analyzer for retrieving the program from said memory, for analyzing the program, and for supplying to said coordinate transformer the coordinate data of the desired displacement position with respect to either a manipulating end of the robot or the center of a sensed image;
• an arm data memory for storing data relative to the respective lengths of said plurality of arms;
• a virtual arm data memory for storing data representing the length of a virtual arm measured from the center of the sensed image to the center of articulation of the arm equipped with said camera, and also for storing data representing the value of a deviation angle formed by said virtual arm and said arm equipped with said camera;
• an adder/subtractor for adding or subtracting the value of the deviation angle stored in said virtual arm data memory, to or from the axial coordinate data outputted from said coordinate transformer;
• and
• a selector for selecting, in response to the coordinate data supplied from said program analyzer, either the content of said arm data memory or the content of said virtual arm data memory as the arm data to be supplied to said coordinate transformer;
• whereby, when said program analyzer receives a displacement command relative to the center of said sensed image, the content of said arm data memory is selected by said selector, and said virtual arm length data is supplied to said coordinate transformer, while said virtual arm deviation angle data is supplied to said adder/subtractor to control movement of the arm, thereby controlling the displacement of the image center with pseudo control in such a manner that the center of the sensed image is positioned at the manipulating end of said virtual arm.