Singularity avoidance for linear motion of 6-DOF manipulator

There is growing interest in the application of robots within industry and agriculture. Kinematic singularities should be considered for stable motion of robotic manipulators for real-world applications which involve linear motion in various areas. In this study, a kinematic singularity avoidance algorithm is proposed for a general 6-DOF manipulator to improve its stability. The proposed method enables the robot to pass the point of singularity while maintaining the planned path. Parts of joint angles are interpolated within the region near the singularity for smooth joint motion. The partial inverse kinematics model is analyzed to derive unknown joint angles. The simulation results show that the robot can move on the planned linear path without position error through singularity configuration. Additionally, the orientation error is much smaller than that of a commercial robot.