Safe Physical Human-Robot Interaction through Variable Impedance Control based on ISO/TS 15066

TL;DR

A novel variable impedance-based controller for robots that ensures safe collaboration by adhering to the ISO/TS 15066 safety standard, namely power and force limiting mode, while achieving higher operational speeds is proposed.

Abstract

The successful implementation of Physical Human-Robot Interaction in industrial environments depends on ensuring safe collaboration between human operators and robotic devices. This necessitates the adoption of measures that guarantee the safety of human operators in close proximity to robots, without constraining the speed and motion of the robotic systems. This paper proposes a novel variable impedance-based controller for cobots that ensures safe collaboration by adhering to the ISO/TS 15066 safety standard, namely power and force limiting mode, while achieving higher operational speeds. The effectiveness of the proposed controller has been compared with conventional methods and implemented on two different robotic platforms. The results demonstrate the designed controller achieves higher speeds, while maintaining compliance with safety standards. The proposed variable impedance holds significant potential for enabling efficient and safe collaboration between humans and robots in industrial settings.

Figures (15)

• Figure 1: Classification of failures caused by engineering, human operator, or environmental conditions errors, adopted from ogorodnikova2008methodology.
• Figure 2: Schematic of the effective mass for the robot moving parts.
• Figure 3: Schematic of the velocity vector $v_\text{max}$ computed in relation to the human $w$---oriented in the direction of their mutual correspondence---and its relationship with the maximum relative velocity vector $v_\text{rel,max}$, which is oriented in the direction of the intended motion $d$.
• Figure 4: Block diagram of the proposed variable impedance controller.
• Figure 5: Schematic of the simulated 3R robot in 2D workspace.