Publications

2024

1. Relaxing Conservatism for Enhanced Impedance Range and Transparency in Haptic Interaction

   Huseyin Tugcan Dinc, Thomas Hulin, Christian Ott, and 1 more author

   IEEE Transactions on Haptics, 2024

   Abs

   The Time Domain Passivity Approach (TDPA) has been ac cepted as one of least conservative tools for designing stabilizing controllers in haptics and teleoperation, but it still suffers from conservatism because it is based on passivity. Additionally, high-frequency, immediate control actions lead to a degradation of transparency. In this paper, we propose a method to relax the conservatism of haptic interaction and enhance stable impedance range while maintaining high transparency. Based on the observation of energy exchange behavior in pressing and releasing paths in haptic interaction, we introduce an energy cycle as a completion of a pressing and releasing path. With this new concept, we compare the energies at the end of each energy cycle to estimate the energy generation and inject adaptive damping to regulate it over upcoming cycles. Because we wait a pressing-releasing cycle is completed, we allow energy to be generated, but we regulate the amount of generated energy over upcoming cycles by injecting adaptive damping. In this way, we perform low-frequency control actions on system dynamics. These in turn enable us to achieve high transparency. We show the validity of the proposed approach through several simulations and experiments, and show that it enhances the stable impedance range and transparency compared to the TDPA.

2. Model-Free Energy-Based Friction Compensation for Industrial Collaborative Robots as Haptic Displays

   Huseyin Tugcan Dinc, Joong-Ku Lee, and Jee-Hwan Ryu

   IEEE/ASME Transactions on Mechatronics, 2024

   Abs

   Collaborative robots are a promising alterna- tive to traditional haptic displays due to their expansive workspaces, ability to generate substantial forces, and cost-effectiveness. However, they have higher levels of fric tion compared to conventional haptic displays, which nega tively impact the precise movement and accuracy of haptic feedback, potentially causing operator fatigue. This article proposes a novel model-free, energy-based approach for estimating and compensating the friction coefficient. Our approach calculates the time-varying impact of frictional forces during an energy cycle, defined as the period be- tween two consecutive zero crossings of the system’s ki- netic energy, based on the energy dissipated by friction. This approach directly estimates the friction coefficients, based on the chosen friction model, without requiring any prior system model information or tuning parameters. The effectiveness of our approach is demonstrated through single and multi-degree-of-freedom human interaction ex- periments using a Franka Emika Panda robot. The results indicate that the proposed approach outperforms state-of- the-art friction compensation methods.

2023

1. Enhancing Contact Stability in Admittance-Type Haptic Interaction Using Bidirectional Time-Domain Passivity Control

   Seong-Su Park, Huseyin Tugcan Dinc, Kwang-Hyun Lee, and 1 more author

   In 2023 32nd IEEE International Conference on Robot and Human Interactive Communication (RO-MAN), 2023

   Abs

   The present paper proposes a novel strategy to enhance admittance-type haptic interaction using bidirectional time-domain passivity control. While admittance-type haptic interaction is widely employed in human-robot collaboration, its ability to render low virtual inertia can be limited, leading to unstable interactions with rigid environments. The proposed strategy seeks to stabilize a lower range of virtual inertia while maintaining responsive behavior in free space. The Franka Emika Collaborative robot was utilized in various experiments to test the approach, and the results indicate that the bidirectional time-domain passivity controller can improve interaction performance relative to the conventional unidirectional time-domain passivity approach. This technique may aid in reducing operator fatigue during the manipulation of heavy, non-back drivable industrial robots while preserving a lightweight feel.

2022

1. CoaxHaptics-3RRR: A Novel Coaxial Spherical Parallel Haptic Device

   Hüseyin Tugcan Dinc, Thomas Hulin, Michael Rothammer, and 5 more authors

   In 2022 IEEE/RSJ International Conference on Intelligent Robots and Systems, IROS 2022, 2022