The class of cameras that are based on ionization sensors, which includes the most common charge-coupled device (CCD) and vidicon cameras, is examined. Camera signals are shown to be corrupted by direction-dependent stationary electronic noise sources and fluctuations due to the statistical nature of the sensing process. The authors develop and test a model of the inherent noises in cameras. These results are confirmed by measurement, and they suggest a locally stationary model of noise for adaptive signal processing.>

The use of edge detection and localizing filters for the recognition of lines (narrow contrasting strips) in visual scenes is shown to produce systematic errors while being suboptimum with respect to noise. The authors derive optimum filters for the detection and localization of lines based on matched filtering in the line normal direction and a Wiener filter in the direction tangential to the line. The matched filters for the detection and localization of line normals in white noise have the form of the system response and its first derivative, respectively. The orthogonal least-restrictive Wiener filter is also closely approximated by the form of the system response in cased where Gaussian response and white noise dominate. Close approximations to the optimum filters for line recognition under these common conditions are readily realized. Line filters were integrated with the Boie-Cox edge detector. Results for images with mixed lines and edges show that the integrated Boie-Cox system is free of the systematic errors common to other edge recognition systems.>

Capacitance guidance is shown to have a potential to provide a simple, direct, and well-understood means for part-to-part homing in some significant classes of assembly. Mutual capacitance homing is introduced, and results are shown for homing applied to die bonding of lightwave detectors, die-to-tape homing in tape automated bonding, and a simple variant of the peg-in-hole problem. Homing tends to reduce the complexity and precision requirements of the assembly machines and the assembled parts. Since homing is between mating surfaces, only they need be well defined. The large capture range of the method also reduces constraints on the initial configuration.>

The forces transmitted through any cross-section of a machine member such as a robot arm can be reduced to a single force and torque acting on any chosen point of the cross-section. The force and torque can be measured by a sensor that replaces the cross-section. A special feature of the sensor discussed here is that it is two dimensional, i.e. that it can be manufactured as a thin, planar sandwich. This makes for simplicity, compactness, low cost and ruggedness. In this paper we derive the constraints on design that must be met in order for the output to be unbiased with respect to force and torque directions. We show that feasible planar designs exist.

The transduction of mechanical forces to representative electrical signals uses a three layer sandwich structure. The top layer is columns of compliant metal strips over a central elastic dielectric sheet. The bottom layer is a flexible printed circuit board with rows of metal strips and multiplexing circuits. Electrically, the sensor is a capacitor array formed by the row and column crossings with the middle layer functioning as a dielectric spring. A readout of the capacitor values corresponds to a sampled tactile image. The reasons for choosing this transduction method, the performance advantages of capacitive sensing and the design and integration of 64 element imagers into the fingers of a controlled compliance gripper are described.

Ultrasonic ranging in air over short distances offers advantages for robotic applications. Such sensing methods can employ transducers small enough to fit into a robot gripper, thereby providing terminal homing capability. Any such short range time-of-flight systems, however, have to solve the problem of rapid receiver recovery after the transmit pulse. In the present case the problem has been solved by an active damping scheme. The transducer is a capacitive element and is connected across an inductor to form an electrically resonant circuit at the acoustic frequency of interest. The LC tank is in the feedback path of a novel circuit that can be changed continuously from positive to negative feedback conditions. When the feedback is positive oscillations rapidly build up, when negative they just as rapidly die down. At the end of each positive - negative cycle essentially all of both the electrical and mechanical energy has been extracted from the system, which is then ready to receive the echo. In this way ranging is readily achieved down to ∼1", which is adequate for robot gripper applications.