Stability of haptic obstacle avoidance and force interaction

Abstract

Abstract-Stability problems associated with haptics and robot control with obstacle avoidance are analyzed. Obstacle avoidance algorithms are revised to accomplish stable redesign using absolute stability and passivity theory. A modification of potential functions for haptic rendering and obstacle avoidance allowing stable operation for high stiffness is proposed. The modification leads to velocity-dependent potential-like repulsive stable haptic force interaction with obstacles. Using strictly positive real re-design, stable force interaction can be provided also for high stiffness of manipulated objects or obstacles.

Robust multi-objective control for systems involving human-in-the-loop passivity constraints with application to electric power steering

“…21 shows [8,19] that unlike passive environments commonly encountered in tele-manipulated robots [5,16], the road-tires' selfaligning moments exhibit non-passive behavior over a large range of vx and road-surface adhesion condition. This shortage of passivity has to be accounted for, to realistically address the uncertainty involved in the EPS environment.…”

“…The uncertainty blocks studied are comprised of passive (possibly nonlinear) dynamic systems and sector-bounded nonlinearities. Specifically, in applications involving human-in-the-loop actuation, such as haptic devices, tele-manipulated robotics [5,13] and robot-assisted surgery [16], the passivity constraint is fundamental to guarantee closed loop stability [13]. For a recent discussion on this subject, see [16] and the references therein.…”

Design of an intermediate layer to enhance operator awareness and safety in telesurgical systems

“…God-object methods [6] and a proxybased method [7] have been proposed to provide a haptic feedback interacting with virtual objects.The interaction between the robot and real environments [8], [9] as well as the obstacle avoidance [10], [11] can also be compared with the framework presented. The intermediate layer presented in this paper, however, allows for more general structures for enhanced operator awareness than the approaches mentioned above.…”