Parameter Identification of a Flexible-Joint Robot Axis using Sinusoidal Position Tracking

This paper presents a novel method for identifying the mechanical parameters of flexible-joint robot axes using sinusoidal position tracking control. Accurate knowledge of mechanical parameters, such as inertia, coupling stiffness, and friction components, is important for designing effective controllers in robotic systems. These parameters are determined from integral values derived from the torque, speed, and position measurements of both the motor and load sides, leveraging the 90 $$^{\circ }$$ phase relationship between position, velocity, and acceleration terms. A robust sinusoidal position controller was developed, and the speed and position measurements of both the motor and load sides were utilized to implement the proposed method. When compared with parameters identified using standard methods, the proposed method shows an absolute percentage error ranging from 3.55% to 14.6% for the inertias and coupling stiffness, and 10.76% to 19% for the friction coefficients. The straightforward implementation and effectiveness of this method make it suitable for applications in industrial robotic arms, where precise control is essential for enhancing performance and operational efficiency.