Robotic arm kinematics and bilateral haptic feedback over an ethernet communications link

Abstract

Combining teleoperation and haptic feedback is a challenging task. Haptic feedback makes a teleoperation system bilateral, introducing sensitivity to communication system delays. Delays are a common cause of control system instability, but with haptic feedback another source of instability is introduced due to the interaction between force and velocity which adds energy to the system. TCP/IP equipment is ubiquitous in both consumer and professional environments. Compared to other communications methods internet links are easy to set up and have widespread deployment. Two aspects of teleoperating a robotic system for field applications are discussed. Firstly kinematics and error propagation actuators to end effector position are analysed. Secondly bilateral haptic feedback over an internet (TCP/IP) link is presented. A novel method combining internet based teleoperation with haptic feedback is proposed to account for the unpredictable delays of internet links affecting stability and transparency. The method has been validated by the prototype haptic teleoperation system built around a pair of Phantom Omni arms.