The purpose of this research effort was to design, fabricate, and test a tactile sensor system consisting of an external high impedance switch circuit, an external multiplexing circuit, and a tactile sensor IC. In order to accomplish this objective, a hardware design and selection process was implemented along with a logical test methodology. An external multiplexer circuit samples all of the array elements in 50 ms. The current prototype sensor has linearity spanning loads of 0.8 g to 135 g, a load resolution of 20 g, and a maximum bandwidth of 25 Hz. Using an elementary shape recognition algorithm the sensor can recognize the shape of a contact load with a spatial resolution on the order of 700 micron. A comparison of three different adhesives used to bond the piezoelectric PVDF film to the surface of the electrode array was made and a urethane adhesive was selected for its superior electrical and physical properties.

The purpose of this research effort was to design, fabricate and test a robotic tactile sensor fabricated from polyvinylidend fluoride (PVDF) films coupled to a silicon substrate containing active amplification circuitry. The integrated circuit incorporated 25 sensor electrode pads (0.6mmx0.6mm each) arrayed in a 5x5 grid with a spacing of 0.6mm between electrodes (this corresponds to a spatial resolution four times greater than the human fingertip). The on-board amplification circuitry consisted of a dual MOSFET amplifier (with a gain of 5) for each sensor electrode. Four different sensor configurations were fabricated and tested. The configurations varied only in the thickness of the PVDF film used (25 microns, 40 microns, 52 microns, and 110 microns). The individual elements of each of the sensor configurations were tested and the sensor based on the 25 micron thick film was considered the optimal sensor of the four. Theses. (mjm).

This research effort pursued the design, fabrication, and test of a robotic tactile sensor. The VLSI integrated circuit (IC) portion of the sensor included a 7 x 7 array of metal electrodes which were individually connected to identical MOSFET amplifiers. A 25 micrometers thick patch (6 mm x 6 mm) of piezoelectric polyvinylidene fluoride (PVDF) film was attached to the array with a non-conductive adhesive, thereby creating an array of taxels. Charge, generated by the PVDF film, was detected by the amplifiers. The outputs of these amplifiers were connected to onchip signal circuitry designed to produce a single stream of serial data. A problem with the signal processing circuit circumvented the proper operation of the entire IC. Therefore, an external multiplexer was used to analyze the performance of a 3 x 3 array of taxels located in the center of the 7 x 7 array. The key factor affecting the performance of the sensor was establishing a uniform initial charge state condition across the 3 x 3 array. Schemes for manifesting this condition were examined as well as characterization of taxel load response. A fundamental image recognition process successfully recognized an applied shape by comparing the pre-load, load, and post-load multiplexed output of the array.

Volume 36 reports (for thesis year 1991) a total of 11,024 thesis titles from 23 Canadian and 161 US universities. The organization of the volume, as in past years, consists of thesis titles arranged by discipline, and by university within each discipline. The titles are contributed by any and all a

The purpose of this research effort was to investigate the performance of a piezoelectric tactile sensor design and appropriately refine it. The sensor was fabricated from an 8 x 8 electrode array MOS integrated circuit. Each taxel in the array was 400 microns x 400 microns. A 6 mm x 6 mm piece of piezoelectric polyvinylidene fluoride was adhered to the electrode array using a urethane dielectric adhesive to form the active sensing area of the sensor. An amplifier was investigated to enhance the range of the tactile sensor's output signal. The amplifier is a high input' impedance differential amplifier with a linear range from 1 to 17 V. The unique feature of the differential amplifier was that it used a power supply of only 12 V. The spatial resolution of the sensor is 0.7 mm. The lower force limit of the sensor is 1 g while the upper limit, limited by a previous amplifier design with a range from 2.5 to 7 V, is 130 g. The dynamic range of the sensor is 130:1. The sensor's force sensitivity is 7.35 g. The pyroelectric bandwidth of the sensor is 0.083 Hz, and the temperature sensitivity of the sensor is 0.39 degrees Celsius. Tactile sensor, Sensors, Piezoelectric, Pyroelectric, PVDF, Thin film.