Machine control device

A machine control device that controls a machine performing a predetermined operation on a workpiece, the machine control device being configured to control a relative position of the machine and the workpiece based on an image including the workpiece imaged by an imaging device, the machine control device comprising:

• a memory storing a program;
• and
• a hardware controller configured to execute the program and control the machine control device to:
• control a position and orientation of the imaging device, and control the imaging device to capture two or more images including the workpiece at two or more different imaging positions based on a control command;
• acquire positional information of the two or more imaging positions;
• restore a measurement distance of the workpiece as positional information of the workpiece based on at least two images among the two or more images, distance information between at least two imaging positions corresponding to the at least two images among the two or more imaging positions, and a parameter of the imaging device, by using a stereo camera method;
• calculate a measurement precision of the measurement distance of the workpiece based on the at least two images, the distance information between the at least two imaging positions, and the parameter of the imaging device;
• specify a partial area of the workpiece as a specified area;
• and
• determine whether the measurement precision of the workpiece satisfies a predetermined precision in the specified area,
• wherein when the measurement precision of the workpiece satisfies the predetermined precision, the hardware controller is further configured to execute the program and control relative positions of a tool of the machine and the workpiece based on the position information of the workpiece calculated, and perform a predetermined operation on the workpiece by using the tool of the machine, and
• wherein parallax information Z for each pixel is obtained by performing area matching on the at least two images, and a measurement distance H of the workpiece is calculated by equation (1) below based on the parallax information Z for the each pixel, distance information between the at least two imaging positions D, and a focal distance f which is a parameter of the imaging device, and
• a distance D′ between the at least two imaging positions at which the measurement precision of the workpiece satisfies a predetermined precision P′ is calculated by equation (3) below based on a measurement distance H of the workpiece and a focal distance f which is a parameter of the imaging device, or a measurement distance H′ of the workpiece at which the measurement precision of the workpiece satisfies the predetermined precision P′ is calculated by a following equation (4) based on the distance between the at least two imaging positions D and the focal distance f which is the parameter of the imaging device,
• H=D×f/Z (1),
• P′=H2/(D′×f) (3),
• P′=H′2/(D×f) (4).