Robustly Stable Haptic Interaction Control using an Energy-bounding Algorithm

Abstract

Stability is a challenging issue when controlling haptic interaction systems because unstable behavior may injure human operators or deteriorate the realism of the provided cues. Based on the passivity condition for sampled-data haptic systems, we propose a novel energy-bounding algorithm to ensure robustly stable haptic interactions. The proposed algorithm limits the energy generated by a sample-and-hold operator within the energy consumable by the effective damping elements in the haptic system. The algorithm also ensures that the VE and controller are passive. This guarantees robustly stable haptic interactions, regardless of the sampling frequency and its variations, but compromises the displayable impedance range of the VE. Simulations and experiments using a commercial haptic device are used to demonstrate the effectiveness of the proposed algorithm.KEY WORDS-haptics1 passivity1 sampled-data system1 stability.

Passive set-position modulation approach for haptics with slow, variable, and asynchronous update

“…Other well-known and related approach is the timedomain passivity approach (or PO/PC) [7,8,9], which however may not be applicable for slow-rate haptics, since the PC/PO has been proved only to enforce stability, not passivity, when continuous dynamics is not negligible [9]. Another related approach is the energy bounding algorithm (EBA) [10], which modulates control force rather than the set-position signal as done here. Yet, it is not clear how this EBA (i.e.…”

“…Yet, it is not clear how this EBA (i.e. its derivation in [10]) can be extended to variable/asynchronous-rate haptics. Perhaps, the most sharp contrast between our framework here and other related works is that our framework aims to exploit the hybrid nature of the problem (i.e.…”

Control of haptic interaction : an energy-based approach

“…Two other non-linear control schemes that are based on enforcing passivity of the telemanipulation system are the Energy Bounding Algorithm (EBA) proposed by Kim and Ryu (2010) and the Passive Set-Position Modulation (PSPM) framework proposed by Lee andHuang (2008b, 2010). Like the TDPC, the EBA was originally developed to implement passive interaction with virtual environments and applied to bilateral telemanipulation by e.g.…”

“…Another approach originating from research towards passive interaction with virtual environments is the Energy Bounding Algorithm (EBA) proposed by Kim and Ryu (2010). Seo et al (2008) have applied the EBA to time-delayed bilateral telemanipulation.…”

“…The first non-linear algorithm that was proposed to implement passive haptic interaction with virtual environments, was the Time Domain Passivity Control (TDPC) algorithm proposed by , which was extended by Ryu et al (2005b) with a reference energy algorithm. Kim and Ryu (2010) proposed an Energy-Bounding Algorithm (EBA), where the energy generated due to the ZOH operation was limited to the energy that was dissipated by the physical viscous friction. Lee and Huang (2008a) have proposed to employ a non-linear virtual coupling element, Passive Set Position Modulation (PSPM), to ensure passivity of the interaction between the user and the virtual environment.…”