On the role of stiffness and synchronization in human–robot handshaking

Abstract

This article presents a system for soft human–robot handshaking, using a soft robot hand in conjunction with a lightweight and impedance-controlled robot arm. Using this system, we study how different factors influence the perceived naturalness, and give the robot different personality traits. Capitalizing on recent findings regarding handshake grasp force regulation, and on studies of the impedance control of the human arm, we investigate the role of arm stiffness as well as the kinesthetic synchronization of human and robot arm motions during the handshake. The system is implemented using a lightweight anthropomorphic arm, with a Pisa/IIT Softhand wearing a sensorized silicone glove as the end-effector. The robotic arm is impedance-controlled, and its stiffness changes according to different laws under investigation. An internal observer is employed to synchronize the human and robot arm motions. Thus, we simulate both active and passive behavior of the robotic arm during the interaction. Using the system, studies are conducted where 20 participants are asked to interact with the robot, and then rate the perceived quality of the interaction using Likert scales. Our results show that the control of the robotic arm kinesthetic behavior does have an effect on the interaction with the robot, in term of its perceived personality traits, responsiveness, and human-likeness. Our results pave the way towards robotic systems that are capable of performing human–robot interactions in a more human-like manner, and with personality.

Human-Robot Handshaking: A Review

“…The mean duration of handshakes was 2.2 s with 24.8 N as the mean sum of forces measured on the robot hand exerted Jouaiti et al [39] Chua et al [18] Avraham et al [9] Kasuga and Hashimoto [41] Dai et al [19] Karniel et al [40] Melnyk et al [3], Melnyk and Henaff [46] Mura et al [51] Nisky et al [58] Papageorgio and Doulgeri [65] W a n g e t a l . [ 86,87] Pedemonte et al [67] Sato et al [71] Yamato et al [89] Zeng et al [91] by the humans.…”

“…Harmonic oscillator models are those that employ harmonic systems, like spring-damper systems [20,51,89] or simpler sinusoidal motions [10,86,87,91] to model the motion during shaking. Some works use both types of harmonic oscillator models in a two-step predictive and reactive system [18,91].…”

“…Dai et al [20] develop a controller for a custom-made hand that controls the stiffness, viscosity and joint angles indepen-dently. Mura et al [51] explore different shaking strategies w.r.t. robotic arm stiffness and their synchronisation with the human during handshaking.…”

Break the Ice: a Survey on Socially Aware Engagement for Human–Robot First Encounters

“…People rated the handshake grip positively in terms of perceived enjoyment and safety. More recently, Mura and colleagues [83] implemented a human-robot handshake controller on a FRANKA robot arm with a custom silicon glove with pressure sensors. Their work focuses on stiffness and synchronization, and they use an EKF to learn human handshake sinusoidal motion parameters.…”

State-Transition Modeling of Human–Robot Interaction for Easy Crowdsourced Robot Control

“…Requesting a handshake was one of the actions the robot performed in this experiment. There has been a previous research on how a robot’s handshake demonstrates human-likeness through the way the robot’s arm moves [ 23 ]. When requesting a handshake in this experiment, the robot moved its hand forward, as illustrated in Figure 7 , and requested a handshake while saying, “May I shake hands with you?” A handshake is a typical greeting in human-to-human communication; however, with human salespeople, the act of shaking hands with a customer is not very common.…”