Task-space position control of concentric-tube robot with inaccurate kinematics using approximate Jacobian

Many medical applications can benefit from the new technology of concentric-tube robot (CTR) due to its miniature size, superior steerability, and controllability of the end tool. However, the kinematic modeling of CTR is challenging because of complicated physical phenomena caused by the elasticity interaction between tubes. Existing control methods of CTR are based on inverse kinematics calculation and hence the control performance largely relies on the accuracy of kinematics model used. In this work, we propose a new control method from the actuator level and show that the control design of actuator input in task-space with approximate Jacobian matrix provides more flexibility and robustness in handling inaccuracy in kinematics model. It is shown through simulation study that the proposed control method presents better performance compared with traditional inverse kinematics based control method in face of kinematics inaccuracy.