Improving the Motion Precision of a 24-DoF Hyper-Redundant Robot through Kinematic Calibration

Hyper-redundant robots with slim bodies and redundant degrees of freedom (DoF) have shown promising applications for inspection and maintenance in confined environments. However, there is still lacking of effective methods to calibrate each section's positioning accuracy of hyper-redundant robots, limiting the ability of obstacle avoidance in confined environments. In this work, based on our 24-DoF hyper-redundant robot, a calibration method is proposed to improve the positioning accuracy of each section. To this end, a kinematic model is firstly established for the 24-DoF hyper-redundant robot. Then, a calibration model is further developed to calibrate the parameters of the kinematic model by simultaneously taking the position errors of each section into consideration. To verify the effectiveness of our method, three calibration simulations under different conditions are conducted, which demonstrate that our calibration method has better performance than existing methods on decreasing position errors of all sections. Further, with our calibration method, the average position error of the hyper-redundant robot decreases from 75.5188 mm to 14.3739 mm. Besides, the experimental results of a path-following experiment demonstrate that the motion precision of the hyper-redundant robot is improved by3 times after the calibration.