Orthogonality Measurement of Three-Axis Motion Trajectories for Micromanipulation Robot Systems.

In robotic micromanipulation systems, the orthogonality of the three-axis motion trajectories of the motion control systems influences the accuracy of micromanipulation. A method of measuring and evaluating the orthogonality of three-axis motion trajectories is proposed in this paper. Firstly, a system for three-axis motion trajectory measurement is developed and an orthogonal reference coordinate system is designed. The influence of the assembly error of laser displacement sensors on the reference coordinate system is analyzed using simulation. An approach to estimating the orthogonality of three-axis motion trajectories and to compensating for its error is presented using spatial line fitting and vector operation. The simulation results show that when the assembly angle of the laser displacement sensors is limited within a range of 10°, the relative angle deviation of the coordinate axes of the reference coordinate frame is approximately 0.09%. The experiment results show that precision of spatial line fitting is approximately 0.02 mm and relative error of the orthogonality measurement is approximately 0.3%.