Key Technology Of Table Tennis Robot

Table tennis is a popular game in our country, even in the world. The potential need for table tennis robot capable of playing with real person is very large. The present table tennis server can shoot ping-pang ball with different rotation, angle and velocity, to entertain player. The limitation is short of fun for it can not hit back the ball from opponent. So, the table tennis with complete function is needed, it can shoot and hit back the ball with smart strategy , and it's parameters can be adjusted to meet the player of different level.To simulate the human's behavior, the table tennis robot shall do target recognition, target positioning, trajectory prediction and motion control. The key issue is quick response, so a structure is proposed exclusively to adjust position and gesture that is composed of a X_Y table and a manipulator with three degree of freedom.In this design, two-eye vision system consisted of two cameras and a PC balances accuracy and speed of calculation. Firstly, the PC acquires the image captured by camera, then recognizes the target from background, and finds out the center of target that is the position of target in two dimensional corridor, use conjunction of two lines to obtain the position in three dimensional corridor; Secondly, analyzes the force and flying mode of ping-pang ball to predict it's trajectory; Finally, motion control is undertaken by the X_Y table and the manipulator of three degree of freedom, the X_Y table is made of two linear motor, this solution can meet the requirement of quick response to the maximum extent, and with the model of linear motor, it's transfer function can be found, and it can be controlled with the digital PID controller.All these function is completed by the motion control card linked with the PC, so a closed loop system has been built to achieve all the behavior of the table tennis robot. In the last, with the simulation of key process using Matlab and Simulink, the design is proved to work perfectly.