An Accurate Position Acquisition Method of a Hyper-Redundant Arm With Load

The constant curvature model is the most widely used kinematics model of hyper-redundant robots. However, it incurs large errors when the robots have load or large deformation. To address these issues, this paper proposes a position acquisition method with combination of the flexible sensors and the kinematics model. A hyper-elastic sensor based on the liquid alloy is developed to directly test the geometric parameters of the robot joints. The mapping model between the resistance and the length of the flexible sensor is also built. By combining with the kinematics model and the testing data of flexible sensors, the overall position of the hyper-redundant arm can be calculated. To verify the position acquisition method, a three joints hyper-redundant arm is built to test the coordinates with non-load and load conditions. The experiment results show the correctness of the method, and it can be extended to various types of hyper-redundant robots.