With the development of compliant mechanisms and tactile skins, social robots are more inclined to physically interact with humans. Touch has been proved highly beneficial in interpersonal social interaction. This motivates social robots to exhibit affective touch abilities. However, most of the studies tackle the consequences and the perception of touch instead of how touching is performed. Understanding the touch manner enables to control robots in a more rich and natural way, but also to detect the intention of the user while touching the robot. This paper focuses on one specific social interaction based on touch, the handshake, and it analyses the pressure exerted by the participants depending on their mood. A corpus of daily repeated handshakes of 11 participants, during 16 days in Human-Human and Human-Robot interactions was produced. A handshake descriptor of 6 variables was computed and allowed to discriminate the participants' behavior. One of the variables (i.e., the maximum pressure on the fingers) enabled to discriminate the mood “Bored” from the others.

Most of the humanoid robots are covered with curved thin shells. To have a sensitive shell on the robot, normally we need to add an extra layer of electrodes or sensors. In this paper, we realized a tactile shell based on a Lamb wave diffraction method. Surface-contact sensing is calibrated and tested with a finger; the spatial resolution is 17 × 13 on a 100 mm × 75 mm projected-dimension surface. Structure of the tactile shell comprises only four small (25 mm2× 0.5 mm) piezoelectric ceramics transducers bonded to the edges of the shell. The sensing results have good accuracy with response time less than 15 ms, the presented method is able to be used for a humanoid robot's whole-body tactile sensing.

In this paper, we talk about compliant bistable mechanisms, a class of mechanical systems that benefit from both compliance, allowing easy fabrication at small scales, and bistability, which brings two passive and stable positions. These properties make them first-class candidates for micro-switches, but also several other robotics appliances. We focus on the actuation of a simple class of bistable mechanisms, the compressed bistable beams, using an innovative smart material, the MFC (for macro-fiber composite). This kind of bistable system is made of a buckled beam, while the MFC is a piezo-based actuator, which can accept large extension deflections (up to 0.5% with a piezo technology). We discuss the impact of the actuator position, and show that it has a major impact on the system response and the switching excitation level. This helps to build more powerful systems and/or reduce the actuator size.

This paper presents a new miniature actuator, which is currently being used to design and develop high resolution, lightweight and compact interfaces for tactile binary information representation such as Braille. Since the main drawback of these devices is their high cost, the proposed actuator exploits the simplicity of its design to provide a low-cost actuation alternative. Based on shape memory alloy (SMA) technology, the actuator consists of an antagonist arranged pair of NiTi helical springs. The actuator of 1.5 mm diameter and 150 mg weight is capable of developing a 320 mN pull force and 1.5 Hz bandwidth by using simple forced-air convection. A combined computational/experimental study on the thermomechanical properties of both SMA active element and actuator is presented to evaluate characteristics such as actuation speed, force and stroke. In conclusion, the prototype and performance results are reported and discussed.

Tactile displays are deformable surfaces that simulate skin deformations that occur when interacting with real surfaces (relieves) by transmitting small-scale shape information and vibration to the fingertip. We present a new vibrotactile display system composed of a matrix of 8/spl times/8 tactile display, a control/power system (electrical hardware) and a software interface dedicated to translate and display a black and white picture on the 8/spl times/8 tactile display with different close-ups. The 8/spl times/8 tactile display is based on a new multi-layer concept. This concept allows developing a new generation of tactile matrices with a high density of micro actuators, a simple assembling process and at a quite competitive price.

MRI (magnetic resonance imaging) is a powerful medical diagnostic tool. Its value would be greatly increased if it were possible to physically manipulate objects within the MRI during imaging. However, the extraordinarily strong magnetic fields used by the MRI make conventional electromagnetic components, such as actuators and sensors, unusable. In this paper, it is shown that devices constructed using binary polymer based actuators, called electrostrictive polymer actuators (EPAM) are able to function effectively within the MRI without degrading its imaging performance. These actuators eliminate the need for conventional electromagnetic actuators and their associated electronics. The binary nature of the actuators eliminates the need for feedback sensors to control the devices motion. The basic concept called digital mechatronics is briefly summarized in this paper. Its application to a reconfigurable MRI surface-imaging coil (RMIC) is also presented. Experimental results are presented that show the EPAM RMIC is completely compatible in the MRI and can be used to enhance the diagnostic capabilities of MRI. The paper also suggests other applications of binary EPAM based actuators for use in MRI systems.

Tactile displays simulate skin deformations that occur when interacting with real surfaces (relieves) by transmitting small-scale shape information and vibration to the fingertip. In this paper, we present a new tactile interface VT (vector-touch) that is based on a rod network positioned in parallel to each other, electric motors to induce a rotation and a positioning mechanism that allows rotating rods to be positioned at different interspaces. Using a rather limited number of actuators, the rods can be driven in such manner to obtain various types of relieves or surface qualities.

This paper presents the characterization in terms of force and displacement of a new interpenetrated network conductive polymer (IPN-CP) to be used as an actuator that works in air conditions. This last property opens many potential applications in robotics, bionics, haptics interface technology (namely tactile feedback devices), etc. Different experimental investigations show that the proposed actuator exhibits acceptable force behavior and capabilities (relatively to its size and mass) when classical solvents are used. However, IPN-CP with ionic liquid solvents show poor capabilities. Since ionic solvents guarantee long life usability, we found it somehow disappointing namely for robotic applications. We give some explanations for that, but we believe that this drawback could mid solutions in the near future.

Binary robotic devices with large numbers of degrees of freedom have been proposed by a number of researchers. However, experimental implementations of these concepts have been built with conventional components. These physical systems are heavy, complex, and far from being practical devices. In this paper, a lightweight, compliant mechanism driven by optimized magnet-coil actuators is proposed and developed as an element for modular hyper-redundant robotic systems. Such elements could be used in a number of applications and would replace conventional, complex, and heavy components. The device has a parallel kinematics structure. Its binary actuation simplifies its control architecture. Analytical and experimental results for a practical prototype system are presented.