A Proximity-Based Framework for Human-Robot Seamless Close Interactions
Liana Bertoni, Lorenzo Baccelliere, Luca Muratore, Nikos Tsagarakis
AI summary
Problem
Existing collision avoidance strategies are overly cautious, frequently halting robot motion and disrupting workflow in dynamic human-robot collaboration. There is a critical need for context-aware reactive behaviors that maintain task continuity while ensuring safety during close interactions.
Approach
The authors integrated on-board Time-of-Flight proximity sensors into a custom lightweight robotic arm and developed a control framework that uses real-time distance data to locally re-plan trajectories and modulate impedance, allowing the robot to smoothly navigate around humans without stopping.
Key results
- Custom lightweight 6-DOF arm with integrated forearm ToF proximity sensors
- Proximity-aware local trajectory re-planning algorithm for continuous collision avoidance
- Time-varying impedance control dynamically adjusting compliance based on task requirements
- Experimental validation in co-assembly and assisted assembly shared workspace tasks
Why it matters
Provides a practical, occlusion-free safety solution for industrial and collaborative settings where uninterrupted human-robot teamwork is essential.
Abstract
The administration and monitoring of shared workspaces are crucial for seamlessly integrating robots to operate in close interactions with humans. Adaptive, versatile, and reliable robot movements are key to achieving effective and successful human-robot synergy. In situations involving unex- pected or unintended collisions, robots must react appropriately to minimize risks to humans while still staying focused on their primary tasks or safely resuming them. Although collision detection and identification algorithms are well-established, more advanced robot reactions beyond basic stop-and-wait reactions have not yet been widely adopted and understood. This limitation highlights the need for more sophisticated robot responses to better handle complex collision scenarios, ensuring both safety and task continuity. This letter introduces a novel complete robotic system that leverages the potential of on-board prox- imity sensor equipment to seamlessly furnish compatible robot reactions while operating in close interactions. With on-board distributed proximity sensors, the robot gains a continuous close workspace awareness, facilitating a transparent negotiation of potential collisions while executing tasks. The proposed system and framework are validated in a collaborative industrial task scenario composed of sub-tasks allocated to the human and the robot and performed within shared regions of the workspace, demonstrating the efficacy of the approach.