Title
Adaptive Control for Improved Transparency in Haptic Simulations
Abstract
Two adaptive nonlinear controllers are proposed for the coupling of haptic devices with impedance-type and admittance-type virtual environments, respectively. Rigid contacts in admittance-type environments are modeled either as a stiff spring or a constraint on the haptic device motion. Both controllers employ user position and force measurements to replace the natural dynamics of the haptic interface with that of an adjustable mass-damper tool. The transparency and stability of the resulting systems are investigated using a Lyapunov analysis and by taking into account uncertain nonlinear dynamics for the haptic device, and uncertain mass-spring-damper type dynamics for the user and virtual environment. It is shown analytically that low-pass filtering of selected terms in the control signal can significantly reduce a stability related lower bound on the achievable synthesized mass of the haptic interface in a discrete-time implementation of the controllers. An optimization problem is formulated and solved to balance impedance reduction against noise amplification in choosing the filter gain and bandwidth. The proposed controllers as well as a conventional penalty-based method are compared in a set of experiments. The results indicate that the controller with an admittance-type constraint-based rigid environment has far superior performance in terms of the range of impedances that it can stably display to the user.
Year
DOI
Venue
2009
10.1109/TOH.2008.18
IEEE T. Haptics
Keywords
Field
DocType
rigid contact,improved transparency,admittance-type environment,proposed controller,haptic interface,haptic device motion,haptic simulations,adaptive nonlinear controller,haptic device,adaptive control,user position,account uncertain nonlinear dynamic,admittance-type virtual environment,nonlinear dynamics,virtual environment,optimization problem,stability,transparency,optimization,lower bound,couplings,haptic devices,discrete time,low pass filters,low pass filter,haptics,impedance,stability analysis
Lyapunov function,Control theory,Nonlinear system,Control theory,Computer science,Simulation,Filter (signal processing),Control engineering,Bandwidth (signal processing),Adaptive control,Optimization problem,Haptic technology
Journal
Volume
Issue
ISSN
2
1
1939-1412
Citations 
PageRank 
References 
7
0.59
18
Authors
2
Name
Order
Citations
PageRank
Amin Abdossalami170.93
Shahin Sirouspour222921.84