A Novel EMG-Based Variable Impedance Control Method for a Tele-Operation System Under an Unstructured Environment

Abstract

In this paper, a novel variable impedance control method is proposed in bilateral tele-operation systems. Inspired by adaptability and stability of the human arm in unstructured environments, the varied parameters of the impedance state for the operator’s arm are transferred to the slave robot to inherit the compliance profile of the human arm in this paper. Firstly, the impedance state of the arm is classified with the naïve Bayes classifier, based on the surface electromyogram signals measured by the MYO arm band. Secondly, during teleoperation tasks, the operator can intuitively regulate the impedance of the arm based on attributes of the remote environment with the help of a haptic device, and a variable impedance control scheme is employed. The target impedance parameters of the impedance controller can change in real time according to the received impedance information of the operator’s arm, so as to realize the simulation of the compliance profile of the slave robot to the human arm, and make the system maintain different compliance in different environments. The comparative experiments, with fixed impedance parameters and variable impedance parameters, are carried out to verify the effectiveness and the feasibility of the proposed method. The experimental results show that the method proposed in this paper has higher flexibility and environmental adaptability than the fixed impedance teleoperation method.

Keywords

• Tele-operation
• variable impedance control
• stiffness estimation
• surface electromyogram
• naïve Bayes classification