Enhanced Pseudo-sensorless Bilateral Teleoperation by PLL αβ-tracker and FPGA

Abstract

In this paper, the problem of external sensors within bilateral teleoperation is addressed. We propose a Phase Locked Loop (PLL) αβ-tracker that presents an improved approach for position and velocity estimation. The proposed approach offers some advantages over the method presented in our previous research that was introduced to enable pseudo-sensorless teleoperation. Such approach applies PMLSM actuators with analog Hall sensors built in a motor housing. They allow obtaining sufficient position, velocity, and force information for teleoperation by a haptic interface. However, main advantage of the method presented in this paper is attributed to enhanced robustness to signal noise and consequently improved haptic fidelity. Furthermore, FPGA has been utilized for the implementation in order to achieve high control rate that was already introduced as a necessity in cutting edge performance systems. Thus, high-performance bilateral control can be achieved. Such bilateral teleoperation with a dedicated haptic interface can significantly improve surgical robotics. The proposed approach was experimentally validated by the simple 1-DoF laboratory bilateral teleoperation system.