Study Of Tripod Robot Control Based On Machine Vision

At present,the traditional industrial sorting process has the drawbacks of high cost and low efficiency,can't attain the desired effect.With the application of robots in the industrial field,the efficiency of industrial process can be improved and the labor cost can be reduced.There are two kinds of industrial robots: series robot and parallel robot.Due to parallel robot's fast speed,high precision and strong bearing capacity,it is widely used in high quality load,precise positioning and high-speed motion.In addition to that,parallel robot specialize in the field of industrial sorting.This paper mainly focuses on the visual recognition,trajectory planning and motion control of Tripod parallel robot which is provided by B&R.The main contents are as follows:(1)The visual system of Tripod robot was designed based on Lab VIEW.Machine vision and image processing were used to recognize the color and shape of the platform geometry after well-understanding of the system structure and platform about Tripod robot.According to image edge extraction,smoothing and centering detection algorithms combined with Lab VIEW's powerful visual module and abundant library functions,pretreatment of the image,the target feature extraction and positioning of the center point were realized.(2)Kinematics and dynamics model of Tripod parallel manipulator were established.The geometric model of the robot was analyzed from two aspects,kinematics and dynamics respectively.According to forward kinematics,inverse kinematics and Jacobian matrix,the kinematics of three-degree-of-freedom parallel manipulator were carried out.The dynamics model of the robot was established based on the interaction of the forces.(3)Tripod robot workspace and end trajectory planning were carried out.The rotating matrix was used to constitute the critical space of the robot end-effector based on the forward kinematics of Tripod.A continuous elliptic trajectory planning method was proposed depend on the basic linear and circular interpolation.By the use of fifth-degree polynomial,the trajectory function was constructed.The workspace and the trajectory planning of the robot was simulated on the platform of MATLAB.(4)Position tracking of Tripod robot was achieved by applying Lyapunov stability adaptive control algorithm.The control model of Tripod robot was obtained by using S function in MATLAB based on the established dynamic model of robot.For a given input,a global stability of adaptive controller was designed.An improved adaptive controller was proposed to eliminate the steady-state error of the position.The final simulated results showed that the position and velocity of the robot joint can be tracked accurately.