Continuum robot shape estimation using permanent magnets and magnetic sensors

Abstract

Continuum robots have attracted more attention owing to their safety and flexibility for confined and complex environment. In order to control the flexible continuum robot more accurately, it is necessary to track the shape of the continuum robot itself in real time. The feedback of the control system is precisely controlled to ensure the safety of the motion of the robot in the unknown environment. This paper proposes to integrate small permanent magnets and magnetic sensors into continuum robot to estimate the shape change. The sensors detect the posture change of magnets, the computer collects data through serial ports. By calculating the relative bending angle of magnets, the data can be imported into Matlab to fit the Quadratic Bézier curve to reconstruct the shape in 2D plane. Considering the interference of multiple magnets, the simulation software Maxwell is used to help arrange the magnets and magnetic sensors reasonably to decrease the significant interference in the sensed magnetic flux density. The experimental results show that the method is applicable to bending angles of 0°–90°. In this range, the maximum and minimum error of the terminal position is 9.339 mm and 0.227 mm respectively, which verifies certain accuracy and feasibility of this method.