Measurement of Robotic Arm Joint Angles Based on Marker Point Position

Aiming at the current problem that the accurate measurement method of the joint angle of the robotic arm relies on the known position and attitude of the end of the robotic arm and the structural dimensions of the robotic arm, a method of measuring the joint angle of the robotic arm based on the position of the marker points is proposed. The method uses a binocular photogrammetric system to obtain the position data of the co-operative targeting ring assembled on each joint surface of the robotic arm and affixed with marking points, and further calculates the joint angles of the robotic arm by geometrical methods using the attitude data in the position data. The experimental results show that the measurement method can effectively measure the angle of each joint of the robotic arm, and the average relative error of the measurement is 0.13627%, with small measurement repeatability error and high measurement accuracy.