This paper discusses the design and testing of an eight-by-eight tactile capacitive array sensor for detection of sub-millimeter features and objects, where the entire sensor array is smaller than normal human spatial resolution of 1mm. Each square tactel is less than 100µm on a side, with similar spacing between elements. The structural material was doped polysilicon with an air gap dielectric of 0.5µm. A thin (50-80µm) protective layer of silicone rubber was adhered to the polysilicon surface of the sensor to provide interpolation of normal loads between elements. The sensors were tested and possessed good spatial uniformity, the capability of detecting millinewton forces, and good interpolation between elements. The sensors had severe hysteresis problems, but no detectable proximity effects. 1

We describe the Tango, a new passive haptic interface for whole-hand interaction with 3D objects. The Tango is shaped like a ball and can be grasped comfortably in one hand. Its pressure sensitive skin measures the contact pressures exerted by the user's hand, and accelerometers within the device measure its motion and attitude. This information can be used for novel modes of interaction with three dimensional objects. We describe the design of the device, and the software for interpreting the sensor data for user interaction. Accompanying this paper, there will be a demonstration of the device at the Hands-On Demo session of the conference. 1

The limitations of rigid #ngertips in the precise and algorithmic study of manipulation have been discussedin many works, some dating back more than a decade. Despite that fact, much of the work in dexterous manipulation has continued to use the #point-contact" model for #nger-object interactions. In fact, most of the existing tactile sensing technologies are not adaptable to deformable #ngertips. In this work we report on experimental results obtained with a deformable tactile sensor whose properties are well-suited to manipulation. The results presented here show that the sensor described provides a rich set of tactile data. 1 Introduction In this work we describe a deformable image-based tactile sensor whose output is an approximation of the tactile surface itself. We present a set of basic tactile sensing experiments designed to demonstrate aspects of the sensor's performance. The ability of our sensor to deform while accurately localizing contact#s# makes it a promising tool fo...

Programming robots by unexperienced human users require methods following the Programming by Demonstration (PbD) paradigm. The main goal of these systems is to allow the unexperienced human user to easily integrate motion and perception skills or complex problem solving strategies. Unfortunately actual PbD systems are dealing only with manipulations based on Pick & Place operations. This paper describes how fine manipulations like detecting screw moves can be recognized by a PbD system. Therefore the question: "What happens during a grasp?" has to be answered. In order to do this, finger movements and forces on the fingertips are gathered and analyzed while a object is grasped. This assume vast sensory employment like a data glove and integrated tactile sensors. An overview of the used tactile sensors and the gathered signals is given. Furthermore a classification of the recognized Dynamic Grasp is pointed out as well as the classification method based on a Support Vector Machine (SVM).

Programming by human demonstration is a new paradigm for the development of robotic applications that focuses on the needs of task experts rather than programming experts. The traditional text-based programming paradigm demands the user be an expert in a particular programming language and further demands that the user can translate the task into this foreign language. This level of programming expertise generally precludes the user from having detailed task expertise because his/her time is devoted to the practice of programming, not the practice of the task. The goal of programming by demonstration is to eliminate both the programming language expertise and, more importantly, the expertise required to translate the task into the language. Gesture-Based Programming is a new form of programming by human demonstration that views the demonstration as a series of inexact "gestures" that convey the "intention " of the task strategy, not the details of the strategy itself. This is analogous...

Easy programming methods following the Programming by Demonstration (PbD) paradigm were developed within the last years. The main goal of these systems is to allow the unexperienced human user to easily integrate motion and perception skills or complex problem solving strategies. Learning form human demonstration assume very vast sensory employment. Due to the fact that missing extracted information from demonstration mostly can be compensated by graphical, speech or gesture interaction, sensorial input simplifies the programming process. Describing unconsciously performed actions or morotic coordinations is very complex and in general not possible. This paper describes how tactile sensors are integrated in a PbD system which learns form human demonstration. Therefore a analysis of the used tactile sensor and its characteristics is performed. Further on the integration of tactile information in the systems cognitive functions is pointed out. Finally it can be concluded that the enhancement of a data glove with tactile sensors improves the analysis of human demonstration. Moreover, the supplied information increases the subsymbolic and symbolic task knowledge which leads to a more reliable recognition of the user's actions.

Abstract — Combining teletaction systems with telemanipulation systems promises to enhance task performance when interacting with remote environments. However, the force scaling inherent in the telemanipulation system affects the ability of the user to control the exploration force. The quality of the tactile signal is therefore impacted, affecting performance in tasks that benefit from spatially distributed force information. We compare performance localizing an embedded lump in a compliant environment using a telemanipulated teletaction system versus a directly manipulated teletaction system. Lump localization accuracy was found to be the same; however, time required to localize the lump was up to 150 % longer for the telemanipulation trials. Based upon our results, we conclude that the ability to maintain an appropriate force in the remote enviroment is necessary to take full advantage of the spatially distributed force information from the tactile sensor. I.

Abstract—Controlling grip force in a prosthetic or robotic hand requires detailed sensory feedback information about microslips between the artificial fingertips and the object. In the biological hand this is accomplished with neural transducers capable of measuring micro-vibrations in the skin due to sliding friction. For prosthetic tactile sensors, emulating these biological transducers is a difficult challenge due to the fragility associated with highly sensitive devices. Incorporating a pressure sensor into a fluid-filled fingertip provides a novel solution to this problem by effectively creating a device similar to a hydrophone, capable of recording vibrations from lateral movements. The fluid conducts these acoustic signals well and with little attenuation, permitting the pressure sensing elements to be located in a protected region inside the core of the sensor and removing them from harm’s way. Preliminary studies demonstrate that high frequency vibrations (50-400Hz) can be readily detected when such a fingertip slides across a ridged surface. F I.

A novel two-degree-of-freedom tactile display reproduces the sensations of sliding contact and incipient slip through the rotation of a ball positioned under the user’s fingertip. A pair of motor-driven wheels actuates the ball via contact friction. Mechanical performance requirements are used to define the dimensions and construction method of the device. Kinematic analysis shows that the drive wheel angles and their contact locations with the ball must be carefully selected in order to accurately control the axis of rotation and speed of the ball. However, psychophysical experiments indicate that some kinematic error is tolerable; errors of up to 20 ◦ in slip angle and 30 % of a nominal velocity may be applied without detection from an average user. The lightweight, modular tactile display was attached to a multi-degree-of-freedom kinesthetic interface and used to display virtual environments with slip. Experimental results demonstrate that users complete a virtual paper manipulation task with lower applied forces using combined slip and force feedback in comparison with conventional force feedback alone. Categories and Subject Descriptors: H.1.2 [Models and Principles]: User/Machine Systems—Human information processing;

Abstract — Grasping of objects by robotic hands in unstructured environments demands a sensor surface that is durable, compliant, and responsive to various force and slip conditions. A compliant and robust skin can be as critical to grasping objects as the sensor it protects. In an effort to combine compliant mechanics and robust sensing, a biomimetic tactile sensor is being developed. Deformations of its skin can be detected by displacing a conductive fluid from the vicinity of electrodes on a rigid core. In this study, we used simplified finite element models to understand the effects of various textures for the inner surface of the skin and then produced the more promising textures by molding the elastomeric skin material against negatives made by stereolithography. The impedance vs. force relationships obtained with these molded skins had the predicted and desired wide dynamic range. By selecting the appropriate materials for the skin and fluid, previously described problems with hysteresis and diffusion losses have been greatly reduced. I.