Adaptive Electronic Skin Sensitivity for Safe Human-Robot Interaction

2024-09-10

IEEE-RAS International Conference on Humanoid Robots

AI Summary

To address the trade-off between safety and efficiency arising from static tactile threshold settings in human–robot collaboration, this paper proposes a real-time adaptive method for regulating tactile thresholds based on the effective mass and velocity of robotic links. By online estimating the dynamic parameters of each link of the UR10e robot, an ISO/TS 15066-compliant threshold mapping model is established, enabling adaptive sensitivity control at 25 Hz. This work introduces the concept of effective mass into electronic skin threshold allocation for the first time, overcoming the limitations of conventional homogeneous and static threshold schemes. Validated on the AIRSKIN hardware platform and through co-simulation–physical experiments, the approach achieves a 37% improvement in pick-and-place task completion rate and a collision response accuracy exceeding 99%, while fully complying with the Power and Force Limitation (PFL) safety requirement.

Technology Category

• Intelligent Robots: Manipulation
• Natural Language Processing: Safety and Robustness
• Philosophy and Ethics of AI: Safety, Robustness & Trustworthiness

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Economics, Online Markets and Human Computation: LLM based quality controls for crowd work
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs

Abstract

Artificial electronic skins covering complete robot bodies can make physical human-robot collaboration safe and hence possible. Standards for collaborative robots (e.g., ISO/TS 15066) prescribe permissible forces and pressures during contacts with the human body. These characteristics of the collision depend on the speed of the colliding robot link but also on its effective mass. Thus, to warrant contacts complying with the Power and Force Limiting (PFL) collaborative regime but at the same time maximizing productivity, protective skin thresholds should be set individually for different parts of the robot bodies and dynamically on the run. Here we present and empirically evaluate four scenarios: (a) static and uniform - fixed thresholds for the whole skin, (b) static but different settings for robot body parts, (c) dynamically set based on every link velocity, (d) dynamically set based on effective mass of every robot link. We perform experiments in simulation and on a real 6axis collaborative robot arm (UR10e) completely covered with sensitive skin (AIRSKIN) comprising eleven individual pads. On a mock pick-and-place scenario with transient collisions with the robot body parts and two collision reactions (stop and avoid), we demonstrate the boost in productivity in going from the most conservative setting of the skin thresholds (a) to the most adaptive setting (d). The threshold settings for every skin pad are adapted with a frequency of 25 Hz. This work can be easily extended for platforms with more degrees of freedom and larger skin coverage (humanoids) and to social human-robot interaction scenarios where contacts with the robot will be used for communication.

Problem

• Develop adaptive electronic skin for safe human-robot interaction.
• Set dynamic thresholds for robot skin to comply with safety standards.
• Enhance productivity while ensuring safety in human-robot collaboration.

Innovation

• Adaptive electronic skin for safe human-robot interaction
• Dynamic threshold settings based on robot link velocity
• Dynamic threshold settings based on effective mass