High-fidelity sliding mode control of a pneumatic haptic teleoperation system

Abstract

For a pneumatic teleoperation system with on/off solenoid valves, sliding mode control laws for position and force ensuring low switching (open/close) activity of the valves are developed. Since each pneumatic actuator has two pneumatic chambers with a total of four on/off valves, 16 possible combinations ('operating modes') for the valves' on/off positions exist, but only seven of which are both functional and unique. While previous work has focused on three-mode slidingbased position control of one pneumatic actuator, this paper develops the seven-mode sliding-based bilateral control of a teleoperation system comprising a pair of pneumatic actuators. The proposed bilateral sliding control schemes are experimentally validated on a pair of actuators utilizing position-position and force-position teleoperation architectures. The results demonstrate that leveraging the additional modes of operation leads to more efficient and smoother control of the pneumatic teleoperation system. It was found that viscous friction forces were crippling haptic feedback in the position-position architecture. Through the use of force sensors, the force-position architecture was able to compensate for the heavy viscous friction forces.

Autonomy in Surgical Robotics

“…The most common approach is based on mechatronics [58], but pneumatic [59] and hydraulic [60] systems have also been proposed. Haptic feedback can be used for tissue palpation, thus identifying buried tissue structures or stiffer regions, to develop assisted guidance of surgical tools in a confined space [61], or to prevent instrument collision [62].…”

A Review of Pneumatic Actuators Used for the Design of Medical Simulators and Medical Tools

“…However, this kind of pneumatic actuator driver is generally limited to the applications where low positioning precision is sufficient as the actuation is performed in an open loop. Nevertheless, in [42], this approach has also been used for teleoperation purpose, with sliding mode control. It has the advantage of requiring widespread low-cost components, but it generates much commutation noise.…”