Initial position detection for Selective Compliance Assembly Robot Arm manipulator joint based on an improved high-frequency injection method

Starting oscillation or slow response will occur if the initial position of the motor used in the Selective Compliance Assembly Robot Arm manipulator is not known. To obtain the initial position of the motor, an improved high-frequency injection method is proposed. First, a high-frequency rotating voltage signal is injected into the stationary coordinate system, and the initial position information is extracted by the heterodyne method. Second, an improved position tracking observer is proposed to estimate the rotor position. Taking the joint of a four-axis Selective Compliance Assembly Robot Arm as an object, a special position servo drive system is designed. The design principle, simulation analysis and experimental verification of the proposed method are presented, respectively. The results show that the initial position of the motor can be estimated by the proposed method, enabling high torque and fast start of the Selective Compliance Assembly Robot Arm manipulator.