39 JUNE 2018 • IEEE ROBOTICS & AUTOMATION MAGAZINE • ©ISTOCKPHOTO.COM/GMAST3R By Benjamin Navarro, Aïcha Fonte, Philippe Fraisse, Gérard Poisson, and Andrea Cherubini An Open-Source Library for Physical Human–Robot Interaction O penPHRI is a C++/Python general-purpose software scheme with several built-in safety measures designed to ease robot progra- mming for physical human–robot inter- action (pHRI) and collaboration. Aside from providing common functionalities, the library can be easily customized and enhanced thanks to the project’s open-source nature. The OpenPHRI framework consists of a two-layer damping controller, depicted in Figure 1. This allows the user to provide compliance and other safety features at both the joint and task levels, depending on the application. pHRI A situation in which direct contact occurs between a person and a robot is referred to as pHRI. From the human perspec- tive, such interplay can be either intentional or undesired. Undesired contact may occur if a person enters the robot workspace without activating a presence-detection system (e.g., a light barrier, floor mat, or laser scanner). Such contact may, of course, lead to severe injuries. Voluntary physical interactions, by contrast, are needed whenever a person con- nects with a robot to stop, guide, or teach it a behavior. This type of interaction is needed in factories so that robots and workers may operate closely or jointly. Other sce- narios include physiotherapy health-care centers and domes- tic assistance cases for elderly or disabled people. In all these situations, measures must be taken to ensure the safety of the people in a robot’s vicinity. Such measures can be implemented at the hardware level, using passively compliant actuators, or at the control/software level. While mechanically compliant devices allow fast impact force absorption, they are available on only a restricted set of robots and add a nonnegligible cost to the platform. However, control-level solutions can be applied to virtually any robot. Moreover, they can provide preventive actions (e.g., collision avoidance and deceleration) that reduce the risk of undesired Digital Object Identifier 10.1109/MRA.2018.2810098 Date of publication: 17 May 2018 1070-9932/18©2018IEEE. TRANSLATIONS AND CONTENT MINING ARE PERMITTED FOR ACADEMIC RESEARCH ONLY. PERSONAL USE IS ALSO PERMITTED, BUT REPUBLICATION/REDISTRIBUTION REQUIRES IEEE PERMISSION. SEE HTTP://WWW.IEEE.ORG/ PUBLICATIONS_STANDARDS/PUBLICATIONS/RIGHTS/INDEX.HTML FOR MORE INFORMATION.