Early detection and removal of small pulmonary nodules significantly improves long term survival rates for patients with lung cancer. To aid in the localization of these tumors during video assisted thoracoscopic surgery (VATS), a tactile imaging system (TIS) is presented. The system consists of a capacitive array sensor mounted on a minimally invasive surgical probe that is integrated with the thoracoscopic imaging. A vision-based algorithm localizes the probe in the live video and overlays a registered pseudo-color map of the measured pressure distribution on the streaming images. The surgeon can locate the hard nodules by scanning the tactile sensor head across the surface of the lung and observing the spatial variation in contact pressures caused by the elasticity differences in the underlying tissue. A validation experiment was conducted to compare the system to a current localization technique using a rigid rod. Results indicate that subjects could localize stiff lumps in lung phantoms more quickly and accurately using the TIS.

This paper presents initial results in integrating touch with vision for delicate manipulation tasks. A generalizable framework of behavioral primitives for tactile and visual feedback control is proposed. Since vision provides position and shape information at a distance, while tactile provides small-scale geometric and force information, we focus on the complimentary roles of vision and touch. We demonstrate that visual feedback can perform the rough positioning needed for tactile sensor feedback, and that grasp force and object orientation can be sensed and controlled with tactile sensing. A force sensor based approach provides a comparison measure, and we observe that the use of tactile sensing results in a more gentle grasp.

This paper presents a system for relaying distributed tactile information from the finger tips of a remote manipulator to the finger tips of a human teleoperator. Tactile array sensors measure the pressure distribution at the contact between the robot hand and the grasped object. A computer samples this pressure signal and applies signal processing algorithms. The resulting signal drives a tactile shape display mounted on the master manipulator. This device raises an array of pins against the operator's finger tip skin to recreate the object shape. This system has been tested on a force-reflecting teleoperated hand. Experiments confirm the system's ability to convey significant contact information.

This paper presents an experimental comparison of tactile array versus force-torque sensing for localizing contact during manipulation. The manipulation tasks involved rotating and translating objects using a planar two fingered manipulator. A pin and a box were selected as limiting cases of point and line contact against a cylindrical robot finger tip. Force-torque contact sensing results suffered from difficulties in calibration, transient forces, and low grasp force. Tactile array sensing was immune to these problems, and the effect of shear loading was only noticeable for a simple centroid algorithm. The results show that with care, both of these sensing schemes can determine the contact location within a millimeter during real manipulation tasks.

This paper presents a tactile sensor that provides transient event information at the finger-object interface. The multi-element stress rate sensor consists of piezoelectric polymer strips moulded into the surface of the rubber "skin" covering the robot finger tip. These piezoelectric elements provide localized information important to manipulation control. We provide experimental results confirming the sensor's ability to detect three parameters. Contact events have been detected for signaling transitions between position and force control. Detecting local skin curvature provided information regarding contact shape and area. Finally, incipient slip, which is generated by small micro slips prior to gross slip, has been detected. By sensing all of these parameters, the utility of the multi-element stress rate sensor seems promising.>