Optimum Condition To Achieve Table Tennis Swing Action Through Establishing And Analysis Of Humanoid Arm Mechanism

The selection of athletes is an important step in the process of training a top table tennis athlete. So far, the main way to select table tennis athletes is through experience, which means the psychology and physical feature are the only factors to be taken into consideration. The selection should be oriented by analyzed data and researches. Through the theory of robot mechanism and computer simulation, this paper analyzed the features of straight-racket-hit skill of table tennis. By using performance index theory of serial robot mechanism, the optimal size of the arm can be got through analysis. It provides basic data for the training and selection of table tennis athletes. Using computer simulation technology, the angle of wrist and forearm of the athlete is analyzed to get the optimal time and angle to achieve the swing action of table tennis.Firstly, the real arm of human body is analyzed to get an abstracted and simplified humanoid arm model. Using D-H representation method of robot mechanism, the coordinate system of humanoid arm mechanism is established and link parameters of the mechanism are given. Using influence coefficient method, the first and second order influence coefficient matrix is established. Using transformation matrix method and influence coefficient method instantaneously, the respective curves of output velocity and acceleration of the mechanism are contoured by Matlab. The coincidence of the curves contoured by the two methods testified the correctness of the established influence coefficient matrix.Secondly, the DOF (degree of freedom) of the mechanism is obtained through the theory of spatial mechanism. Using the data of the size of human arm from the references, the dynamic performance of the humanoid arm mechanism is analyzed according to the performance index theory of 6-DOF serial robot. Through analyzing the performance index atlas of velocity, acceleration, linear velocity, linear acceleration etc., the relationship of arm size and dynamic performance of the mechanism is obtained. The obtained optimal size of humanoid arm mechanism provides basic data for the training and selection of table tennis athletes.Lastly, the computer simulation environment is established using C# language and OpenGL graphic library. Take the angle of arms and time when hitting the ball into consideration, the simulation of real arm of human body is established. Finally, the whole simulation scene of table tennis swing demonstration action is given.