Kinematic Analysis and Admittance Control of a 7-DOF Robotic Arm

With the increasing demand for high-precision dynamic interaction tasks in industrial automation, the 7 DDF robotic arm faces the dual challenges of insufficient kinematic modeling accuracy and inadequate end-effector force compliance in complex interaction tasks. This paper focuses on the Realman RM75 seven-degree-of-freedom robotic arm as the subject of study, enhancing its kinematic modeling through an Modified Denavit-Hartenberg (D-H) parameterization method and arm shape angle parameterization technique. Furthermore, it achieves force-compliant control of the robotic arm based on an admittance control strategy. First, a kinematic model of the robotic arm is developed using a Modified D-H parameter approach combined with an arm angle parameterization method to derive a closed-form solution for inverse kinematics. Second, an admittance control framework is designed to adjust the end-effector pose in real time via a virtual spring-damping system, facilitating compliant control in multi-dimensional force interaction scenarios. The experimental results demonstrate the designed control system can achieve good force compliance control at the end of the robotic arm under the action of external contact forces.