Transmission Characteristics Analysis and Compensation Control of Double Tendon-sheath Driven Manipulator

Abstract

The double tendon-sheath drive system is widely used in the design of surgical robots and search and rescue robots because of its simplicity, dexterity, and long-distance transmission. We are attempting to apply it to manipulators, wherenon-linear characteristics such as gaps, hysteresis, etc., due to friction between the contact surfaces of the tendon sheath and the flexibility of the rope, are the main difficulties in controlling such manipulators. Most of the existing compensation control methods applicable to double tendon-sheath actuators are offline compensation methods that do not require output feedback, but when the system’s motion and configuration changes, it cannot adapt to the drastic changes in the transmission characteristics. Depending on the transmission system, the robotic arm, changes at any time during the working process, and the force sensors and torque sensors that cannot be applied to the joints of the robot, so a real-time position compensation control method based on flexible cable deformation is proposed. A double tendon-sheath transmission model is established, a double tendon-sheath torque transmission model under any load condition is derived, and a semi-physical simulation experimental platform composed of a motor, a double tendon-sheath transmission system and a single articulated arm is established to verify the transfer model. Through the signal feedback of the end encoder, a real-time closed-loop feedback system was established, thus that the system can still achieve the output to follow the desired torque trajectory under the external interference.

Closed-loop Control Design and Motor Allocation for a Lower-limb Cable-driven Exoskeleton: A Switched Systems Approach

“…The synchronization control for the extension motor is designed to track the flexion motor angle θ f l . Taking derivative of the filtered tracking error (13), pre-multiplying by J ex , substituting (12), and then performing algebraic manipulation yields…”

“…Since there exist discontinuous terms in motor synchronization control input ( 16) and ( 19), the Filippov method is used to analyze the system's stability. Let z 2 (t) be a Filippov solution to the differential inclusion ż2 ∈ K[h](z 2 ), where K[•] is defined as in [20] and h is defined by using ( 20) and (13)…”

“…Multiple strategies have been developed to mitigate the undesirable slacking behavior and coordination issues in cabledriven systems. A mechanical approach with closed pulley transmission (one motor with two cables) was used in [13] to achieve bi-directional joint movement. Alternatively, a motor synchronization approach was developed in [7], where one motor controlled the joint torque, and its antagonist motor was synchronized using a closed-loop proportional controller.…”

Transmission Backlash Compensation and Grasping Force Estimation of Surgical Instruments for the Laparoscopic Minimally Invasive Surgery Robot

“…Agrawal et al proposed the mathematically rigorous distributed parameter model for cable-conduit actuation with any curvature and initial tension profile across the cable, which is described by a set of partial differential equations in the continuous time-domain, and is also discretized for its effective numerical simulation of cable motion and tension transmission across the cable [17]. Wu H et al proposed a real-time position compensation control method based on the deformation of flexible cables, by establishing a torque transmission model of double tendon-sheaths under arbitrary load conditions, and developed two open-loop control strategies for friction and deformation compensation [18]. Farshad et al proposed a new motion transmission model of a tendon-sheath pulley mechanism to estimate the motion error and force of da Vinci system surgical instruments, and used this model for the position control of the instrument tip to eliminate hysteresis and achieve an accurate trajectories track [19,20].…”

Investigation on the Tip Positioning Accuracy of Cable-Driven Serpentine Manipulators

“…Li et al [14] designed and built a wire-driven serpentine robot arm which is made of a number of rigid nodes connected by two sets of wires. Wu et al [15] proposed a real-time position compensation control method based on flexible cable deformation. Qian et al [16] studied a cable-driven parallel robot for 3D printing to obtain a larger workspace rather than traditional 3D printing devices.…”