Solving Inverse Kinematics Model for 7-DoF Robot Arms Based on Space Vector

The 7-DoF Manipulator has a high degree of flexibility and can perform many complex tasks for humans, therefore widely used in many fields. This paper proposes a new method to solve the inverse kinematics model for 7-DoF manipulators. Specifically, it focuses on how to derive equations for the feasible space of the endpoint of each joint and correspondingly the feasible space of each arm-angle when the endpoint of the robot arm is given, which lays the foundation for the robotic arm to complete obstacle avoidance and optimal path planning tasks. First, the influence of the first three joints and the last three joints on the end position of the robotic arm is decoupled. Based on this decoupling, the relationship between the last three joint angles and the end position of the robotic arm is solved through the space vector. Furthermore, the relationship between the end position of the robotic arm and the first three joint angles is obtained through coordinate rotation. Finally, this paper validates the results by simulations.