Enhancing the Rate-Hardness of Haptic Interaction: Successive Force Augmentation Approach

Harsimran Singh,Jee-Hwan Ryu,Bernhard Weber,Dominik Janetzko,Aghil Jafari,Chan-Il Lee

doi:10.1109/tie.2019.2918500

Abstract

There have been numerous approaches that have been proposed to enlarge the impedance range of haptic interaction while maintaining stability. However, enhancing the rate-hardness of haptic interaction while maintaining stability is still a challenging issue. The actual perceived rate-hardness has been much lower than what the users expect to feel. In this paper, we propose the successive force augmentation (SFA) approach, which increases the impedance range by adding a feed-forward force offset to the state-dependent feedback force rendered using a low stiffness value. This allows the proposed approach to display stiffness of up to 10 N/mm with Phantom Premium 1.5. It was possible to further enhance the rate-hardness by using the original value of virtual environment stiffness for feedback force calculation during the transient response followed by normal SFA. Experimental evaluation for multi-DoF virtual environment exhibited a much higher displayed stiffness and rate-hardness compared to conventional approaches. Two user studies revealed that the increase of rate-hardness due to SFA allowed the participants to have a faster reaction time to an unexpected collision with a virtual wall and accurately discriminate between four virtual walls of different stiffness.

Highlights

E NLARGING the impedance range and increasing the rate-hardness of haptic interaction while maintaining stability has been a classical issue on the control of haptic interfaces
3) Discussion: The user study served as a preliminary investigation on examining whether different kde are distinguishable by human operators using the extended Successive Force Augmentation (SFA) approach
This study should serve as an initial proof of concept that different kde rendered by extended SFA approach would lead to a difference in behavior for the operators

Summary

Introduction

E NLARGING the impedance range and increasing the rate-hardness of haptic interaction while maintaining stability has been a classical issue on the control of haptic interfaces. Lawrence et al [1] described rate-hardness as a tool for humans to perceive the actual hardness of the virtual environment (VE). It is the initial rate of the change of force. Numerous approaches have been proposed, the actual achievable impedance and rate-hardness are still much lower than what the user perceives from real environment. The actual implementation of haptic interaction to the wider range of applications has been severely limited

Methods

Results

Discussion

Conclusion