Quantitative Safety Guarantees for Physical Human-Robot Interaction

Abstract

If robots are to be introduced into the human world as assistants to aid a person in the completion of a manual task two key problems of today's robots must be solved. The human-robot interface must be intuitive to use and the safety of the user with respect to injuries inflicted by collisions with the robot must be guaranteed. In this paper we describe the formulation and implementation of a control strategy for robot manipulators which provides quantitative safety guarantees for the user of assistant-type robots. We propose a control scheme for robot manipulators that restricts the torque commands of a position control algorithm to values that comply to preset safety restrictions. These safety restrictions limit the potential impact force of the robot in the case of a collision with a person. Such accidental collisions may occur with any part of the robot and therefore the impact force not only of the robot's hand but of all surfaces is controlled by the scheme. The integration of a visual control interface and the safely controlled robot allows the safe and intuitive interaction between a person and the robot. As an example application, the system is programmed to retrieve eye-gaze-selected objects from a table and to hand them over to the user on demand.

Safety Evaluation of Physical Human-Robot Interaction via Crash-Testing

“…the Head Injury Criterion (HIC) [6], [7]) were mainly evaluated in simulation so far. Further approaches are outlined in [8], [9], [10], but the importance of human biomechanics was barely investigated. To fill this gap we decided to measure the potential danger emanating from the DLR lightweight robot III (LWRIII) by impact tests at a certified crash-test facility.…”

Injury evaluation of human-robot impacts

“…2. A numerical value of ≤ 650 corresponds to very low injury by means of the EuroNCAP 4 . For further information on HIC, AIS and other Severity Indices (not only for the head), please refer to [6].…”

“…Clearly, the saturation effect mentioned in Sec. II was observed, as the 3 ||ẍ|| 2 =Euclidean norm 4 The initial crash-tests with the LWRIII were carried out at the German Automobile Club ADAC. They are the basis for the tests presented in this video and are evaluated according to the EuroNCAP.…”

“…In this video the effect of robot mass, robot speed, and constraints in the environment on injury severity during human-robot impacts are explained and supported by various crash-tests. Although there is some literature present treating safety issues in human-robot interaction [1], [2], [3], [4], [5], there was so far no effort taken to analyze real world threats via impact tests at standardized crash-test facilities. This was to our knowledge only carried out in [6] up to now.…”

A tool for the evaluation of human lower arm injury: approach, experimental validation and application to safe robotics

“…In this context, a significant body of work was conducted in the field of human-robot interaction safety. [10][11][12][13][14] However, human-robot collisions and the resulting injuries have only recently been systematically investigated for various blunt impacts in refs. [15], [16].…”