Event-triggered Hybrid Force Feedback Architecture With Tank-based Stabilization Method for Complicated Bilateral Teleoperation Tasks

Abstract

Bilateral teleoperation with force feedback allows the operators to apply their skills to accomplish challenging tasks safely. Most teleoperation bilateral systems are designed for single interaction scenarios and low-frequency force feedback, which limits their overall performance in complex interaction tasks. Furthermore, the use of passive controllers to ensure system stability can lead to further reductions in force transparency. This paper addresses the hybrid force feedback problem in complex interaction tasks with multiple stages, aiming at enhancing the practicality and robustness of teleoperation systems for complex interaction tasks, as well as reducing the force distortion caused by passive controllers. Firstly, an event-triggered hybrid force feedback architecture is proposed. Within this architecture, we introduce a two-channel fully transparent method with an explicit force controller (FT2-EFC), to enable model-free force tracking during both free motion and vibration contact stages. Besides, an adaptive impedance matching (AIM) algorithm is proposed to improve the physical interaction characteristics in the contact transient stage. Secondly, we present the operator passivity reference dual boundary energy tank (OPRDB-ET) method, which not only ensures the delay stability of the force architecture but also minimizes force distortion resulting from passive damping injection. Finally, experiments demonstrated that the proposed methods ensure the accurate tracking ability of hybrid forces in all stages of complicated interaction tasks and the slight force distortion under communication delay.