RTOS based embedded controller implementation of a bilateral control system

Bilateral tele-operation involves realization of the law of action and reaction between the human and the remote environment. In this research, an embedded system based bilateral control was developed on a microcontroller based motor driver platform. Bilateral tele-operation needs real-time representation of the forces and positions. This challenge was accomplished by incorporating a real-time operating system (RTOS) with a resource limited microcontroller. Sensorless torque detection technique was used to find the external torque while disturbance observer was used as a disturbance rejection tool and also to improve the system’s robustness. When the motion controller was implemented on a microcontroller, 0 - 30 Hz frequency of force bandwidth could be achieved. In an ideal bilateral control, force/position errors should be zero. The experimental results in contact motion showed a force error less than 4 % and a position error less than 6 %, which validates the proposal. This was a significant achievement as the bilateral controllers have never been successfully implemented using a microcontroller.

DOI: http://dx.doi.org/10.4038/jnsfsr.v42i3.7395

J.Natn.Sci.Foundation Sri Lanka 2014 42 (3): 217-228