Improving dependability in robotized bolting operations

TL;DR

This paper presents a control framework for dependable robotic bolting that enhances safety, fault management, and operator awareness through advanced control architecture, multimodal interfaces, and supervisory coordination, validated in pipe flange assembly.

Contribution

It introduces a novel control and human-robot interaction framework for reliable robotized bolting, improving fault detection and operator situational awareness in industrial tasks.

Findings

Improved fault detection capabilities in robotic bolting operations.

Enhanced operator situational awareness through multimodal HRI.

Accurate and compliant execution of bolting tasks under fault conditions.

Abstract

Bolting operations are critical in industrial assembly and in the maintenance of scientific facilities, requiring high precision and robustness to faults. Although robotic solutions have the potential to improve operational safety and effectiveness, current systems still lack reliable autonomy and fault management capabilities. To address this gap, we propose a control framework for dependable robotized bolting tasks and instantiate it on a specific robotic system. The system features a control architecture ensuring accurate driving torque control and active compliance throughout the entire operation, enabling safe interaction even under fault conditions. By designing a multimodal human-robot interface (HRI) providing real-time visualization of relevant system information and supporting seamless transitions between automatic and manual control, we improve operator situation awareness and fault detection capabilities. A high-level supervisor (SV) coordinates the execution and manages transitions between control modes, ensuring consistency with the supervisory control (SVC) paradigm, while preserving the human operator's authority. The system is validated in a representative bolting operation involving pipe flange joining, under several fault conditions. The results demonstrate improved fault detection capabilities, enhanced operator situational awareness, and accurate and compliant execution of the bolting operation. However, they also reveal the limitations of relying on a single camera to achieve full situational awareness.