Research On The Error Control Of Spray Robot Pattern Width

With the developing of manufacturing automation, industrial robots are more widely used, and gaining a lot of attention. Painting robot is a special kind of industrial robot. They have some unique characteristics in areas such as structural design, trajectory planning and process control. At present, the painting robot systems in used are imported products. Relevant technical is self-contained. Open development interface is limited. It is difficult for application development based on these systems. In this paper, all research works are base on a certain spraying operating system. The research goal is to reduce the error of width of the spray pattern. By using theoretical analysis and experimental verification, the paper discusses on how to achieve pattern width error control by using robot motion compensation and by using additional device. This paper explores the method of improving the performance of spraying robot and realization method, and can provide a reference for similar applications research. Contents include:6-DOF robot kinematics modeling, gun spray deposition modeling, control systems research, design and implementation of the compensation mechanism.Firstly, the article models on spray deposition process by spray experiment, and selects variables which is suit for engineering applications, then divides into two ideas for spray width control. The article compares the step and the cost qualitatively, optimizes the easy way to achieve, analyses and tests the compatibility of the new method with the original system. Finally, the article builds up a functional test platform. The work focuses on theory analysis and technical implementation of improving the width control. The main research work and conclusions are as follows:1. A6-DOF robot is modeled, the homogeneous transformation matrix is defined. Kinematics model is derived. The way to solve inverse kinematics algorithm is studied. The way to solve inverse kinematics algorithm of a robot which is meeting the Pieper guidelines is presented in line, and a more universal numerical solution algorithm of robot inverse kinematics is briefly introduced. The inverse kinematics solver step of spraying distance error is summarized, and the feasibility of using the robot itself for real-time compensation structure is discussed.2. The deposition rate of spray painting is modeled, the characteristics and modeling method of some typical model is compared. By spray tests, coating distribution law model and Pattern width model is carried out. The article presented an error compensation control scheme. By calibration, the scheme exclude the working pressure, coating viscosity, temperature and other external conditions disturbance on Pattern width, and by changing spray distance the scheme can decrease the spray fan width error.3. The spray width error compensation experimental platform is designed and built. The composition of test platform is introduced, using servo motors, motion controllers, DSP, distance sensors and industrial cameras. The platform is with function of calibration coefficient, error compensation and change the width of the pattern and other functions according to the setting. After coordinate transformation, the system is able to compatible with the original trajectory of robotic spray painting system. By establishing the bounding box model base on the original robot off-line simulation software Robot Studio, the error compensation mechanism is compatible with the anti-collision detection function. Tests showed that the experimental platform can improve the spray pattern of the original system error rejection level to a certain extent, thereby reducing the requirements of modeling accuracy, Parking precision and target repeat accuracy.