Optimal Prioritized Dissipation and Closed-Form Damping Limitation under Actuator Constraints for Haptic Interfaces

TL;DR

This paper introduces a novel damping limitation method for haptic interfaces that optimally manages actuator power limits while maximizing transparency, using a closed-form solution validated experimentally.

Contribution

It presents a new prioritized dissipation approach that accounts for actuator power constraints and maximizes transparency in multi-DoF haptic systems.

Findings

The proposed method effectively manages actuator power limits.

Closed-form solution simplifies implementation.

Experimental validation confirms robustness and improved transparency.

Abstract

In haptics, guaranteeing stability is essential to ensure safe interaction with remote or virtual environments. One of the most relevant methods at the state-of-the-art is the Time Domain Passivity Approach (TDPA). However, its high conservatism leads to a significant degradation of transparency. Moreover, the stabilizing action may conflict with the device's physical limitations. State-of-the-art solutions have attempted to address these actuator limits, but they still fail to account simultaneously for the power limits of each actuator while maximizing transparency. This work proposes a new damping limitation method based on prioritized dissipation actions. It prioritizes an optimal dissipation direction that minimizes actuator load, while any excess dissipation is allocated to the orthogonal hyperplane. The solution provides a closed-form formulation and is robust in multi-DoF scenarios, even in the presence of actuator and motion anisotropies. The method is experimentally validated using a parallel haptic interface interacting with a virtual environment and tested under different operating conditions.