Control Research Of Image-Based Robotic Visual Servo System

Control research of image-based robotic visual servo system includes robot system unit, Panasonic's servo system unit, PMAC control block unit, DSP image processing system unit, FCMAC control emulator unit and synthesis experiment unit.The robot of this paper is a planar robot with two revolving joints. It only runs in direction X and Y. The joints are droved by Panasonic's servo electromotor. A CCD camera is fixed on the second arm's end of the robot. The robot visual servo system's mathematics model is built, and transformation of three-dimensional coordinate is steered clear of. Image Jacob matrix which describes relation of image coordinate's changes and changes of the robot joints'angles is built, and its reversion matrix is gained and applied in the system of image—based robotic visual servo .The Panasonic's servo system is a numeric and precise AC servo control system. It drives two joints of the robot directly, receives torque control instruction from the PMAC block, and feeds back signals of the joints'electromotor encoder synchronously. The PMAC control block uses DSP chips as its CPU, and also it is an unattached and Real-time motion control card. It relies on the instruction of the main control program and controls the motions of the robot joints, cooperating with The Panasonic's servo system.The DSP image processing system processes object's colored video images which is taken by CCD camera. It transforms these colored images to gray images, and gets the circular object's edges after process of image's two-value arithmetic, median arithmetic, Sobel edge arithmetic in turn, then gains the centroid pixel coordinate of the object after process of dot Hough transform arithmetic. The system sends these coordinate values to the main control program which is running in the industry control computer by the serial interface and forms video servo circulation.The FCMAC is a fuzzy controller which is similar with human's cerebellum frame. This paper applies it to the research of image—based robotic visual servo system. The results of the Simulation experiment show that for static or linear object orientation and track of various types of motions,the performances of the control system are good .The hardware system is built on reasonable function request. The experiment of Control research of image—based robotic visual servo system comes true in the actual robot system by using the main control program.