Robotic devices can be leveraged to raise the abilities of humans to perform demanding and complex tasks with less effort. Although the first priority of such human-robot interaction (HRI) is safety, robotic devices must also be intuitive and efficient in order to be adopted by a broad range of users. One challenge in the control of such assistive robots is the management of the end-effector orientation, that is not always intuitive for the human operator, especially for neophytes. This paper presents a novel orientation control algorithm designed for robotic arms in the context of HRI. This paper aims at making the control of the robot's orientation easier and more intuitive for the user, both in the fields of rehabilitation (in particular individuals living with upper limb disabilities) and industrial robotics. The performance and intuitiveness of the proposed orientation control algorithm is assessed and improved through two experiments with a JACO assistive robot with 25 able-bodied subjects, an online survey with 117 respondents via the Amazon Mechanical Turk and through two experiments with a UR5 industrial robot with 12 able-bodied subjects.

This paper presents the design of a locomotion interface for gait simulation and interaction with a virtual environment. The proposed mechanical interface is based on two planar two-degree-of-freedom belt-driven mechanisms which fully decouple the vertical and horizontal motion of two supporting footplates. Force sensors are mounted under the footplates in order to move the end effectors according to the user's intentions. The user's feet are rigidly attached to the footplates but a system of hinges allows an additional unactuated two-degree-of-freedom motion. A lag controller allows the user to move the end-effectors freely and a virtual floor based on a virtual spring and damper restrains the end-effectors' movements so that the user experiences an intuitive contact with the ground. Finally, preliminary experiments are reported in order to demonstrate the capability of the locomotion interface for gait simulation.