Designing robots that interact naturally with people requires the integration of technologies and algorithms for communication modalities such as gestures, movement, facial expressions and user interfaces. To understand interdependence among these modalities, evaluating the integrated design in feasibility studies provides insights about key considerations regarding the robot and potential interaction scenarios, allowing the design to be iteratively refined before larger-scale experiments are planned and conducted. This paper presents three feasibility studies with IRL-1, a new humanoid robot integrating compliant actuators for motion and manipulation along with artificial audition, vision, and facial expressions. These studies explore distinctive capabilities of IRL-1, including the ability to be physically guided by perceiving forces through elastic actuators used for active steering of the omnidirectional platform; the integration of vision, motion and audition for an augmented telepresence interface; and the influence of delays in responding to sounds. In addition to demonstrating how these capabilities can be exploited in human-robot interaction, this paper illustrates intrinsic interrelations between design and evaluation of IRL-1, such as the influence of the contact point in physically guiding the platform, the synchronization between sensory and robot representations in the graphical display, and facial gestures for responsiveness when computationally expensive processes are used. It also outlines ideas regarding more advanced experiments that could be conducted with the platform.

Johnny-0, shown in Figure 1, is our new humanoid robot which integrates an expressive face on an orientable head, two arms with 4 degrees of freedom (DOF) each and grippers, mounted on an omnidirectional, non-holonomic mobile platform. Our underlying goal with Johnny-0 is to design a platform capable of natural reciprocal interaction (motion, language, touch, affect) with humans, to address integration issues associated with advanced motion, interaction and cognition capabilities on the same platform, and their use in unconstrained real world conditions. To do so, compliance is a necessity to provide natural and safe interactions.

For complex robotic tasks (e.g., manipulation, locomotion), the lack of knowledge of precise interaction models, the difficulties to precisely measure the task associated physical quantities (e.g., position of contact points, interaction forces) in real-time, the finite sampling time of digital control loops and the non-collocation of sensors and transducers have negative effects on performance and stability of robots when using simple force or simple movement controllers. To cope with these issues, a new compact design for high performance actuators specifically adapted for integration in robotic mechanisms is presented. This design makes use of a mechanical differential as its central element. Results shown that differential coupling between an intrinsically high impedance transducer and an intrinsically low impedance mechanical spring provides the same benefits as serial coupling, but in a more compact and simple design. This new actuator, named Differential Elastic Actuator (DEA), provides interesting design implementations, especially for rotational actuators used for mobile robot locomotion.

The most common ground locomotion method to make a mobile robot move is to use two-wheel drive with differential steering and a rear balancing caster. Controlling the two motors independently makes the robot non-holonomic in its motion. Such robots can work well indoor on flat surfaces and in environments adapted for wheelchairs. But the benefit of providing mobility to a robot directly relies on its locomotion capability, for handling different types of terrains (indoors or outdoors) and situations such as moving slowly or rapidly, with or without the presence of moving objects (living or not), climbing over objects and potentially having to deal with hazardous conditions. It is with this objective in mind that we designed AZIMUT. AZIMUT is a legged tracked wheeled robot capable of changing the orientation of its four articulations. Each articulation has three degrees of freedom (DOF): it can rotate 360deg around its point of attachment to the chassis, can change its orientation over 180deg, and rotate to propulse the robot.

This video shows the functionalities of a 3 serial DOF robotic arm. Each DOF is actuated with a patent pending differential elastic actuator (DEA) [1,2]. Compared to the abundantly studied series elastic actuator [3,4], DEA uses a differential coupling between a high impedance mechanical speed source and a low impedance mechanical spring. Possible implementations of a mechanical differential include the use of a standard gearbox, harmonic drive, cycloidal gearbox, bar mechanism, cable mechanism and all other mechanism that implement a differential function between three mechanical ports. For the implementation reported in this video, we used a harmonic drive for a very compact design. A passive torsion spring (thus the name elastic), with a known impedance characteristic corresponding to the spring stiffness, is used, with an electrical DC brushless motor. A non-turning sensor connected in series with the spring measures the torque output of the actuator.

AZIMUT is a mobile robotic platform that combines wheels, legs and tracks to move in three-dimensional environments. The robot is symmetrical and is made of four independent leg-track-wheel articulations. It can move with its articulations up, down or straight, or to move sideways without changing the robot's orientation. To validate the concept, the first prototype developed measures 70.5 cm/spl times/70.5 cm with the articulations up. It has a body clearance of 8.4 cm to 40.6 cm depending on the position of the articulations. The design of the robot is highly modular, with distributed embedded systems to control the different components of the robot.