Optimal Prioritized Dissipation and Closed-Form Damping Limitation under Actuator Constraints for Haptic Interfaces
Francesco Porcini, and Antonio Frisoli
AI summary
Problem
Existing passivity controllers for haptic interfaces use conservative, norm-based damping limits that clash with individual actuator power constraints, risking stability violations or degrading transparency in multi-DoF systems.
Approach
The method splits damping into a high-priority component along the rendering direction to reduce actuator load, and a low-priority orthogonal component for residual energy, both computed in closed-form to respect individual actuator limits.
Key results
- Closed-form prioritized damping limits that respect individual actuator power constraints
- Robust stability and transparency in multi-DoF systems with anisotropic velocities and actuator limits
- Experimental validation on a parallel haptic interface outperforming state-of-the-art norm-based methods
- Elimination of online optimization while maintaining strict passivity guarantees
Why it matters
Enables safer, more transparent haptic feedback for teleoperation and virtual environments by aligning passivity control with real-world hardware capabilities.
Abstract
In haptics, guaranteeing stability is essential to ensure safe interaction with remote or virtual environments. One of the most relevant method 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 devices’ 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 priorities 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.