Other

Gm Global Technolgoy Operations, Inc.

Robert Hickling

Peng Lee

Douglas A Feldmaier

Jing-yau Chung

James A Hamburg

Kenneth J Zielesch

Virgil R Dahlmann

Kelly A Talaki

Wei Wei

Karen M Pirrallo

Shi-Tse Chang

Method and apparatus for vibrometry, gauging, condition monitoring and feedback control of robots, using one or more ultrasonic probes () that are non-contact and form a focused beam. The ultrasonic probe is driven by a pulser-receiver () controlled by a computer. The probe has a substantially spherical transducer surface () that forms the focused beam within a gas or a liquid. The curvature of the transducer surface determines the focal length () and the extent of the focal region () of the beam. For greatest lateral accuracy, measurements are made within the focal length, where beam is narrowest. Diameter () of the probe determines the size of the beam, which can be chosen to satisfy a particular application. The focused beam has acoustic depth of field (), which is the furthest distance from the probe to a surface () that can return a measurable echo to a pulse emitted by the probe.

Non-contact, focused, ultrasonic probes for vibrometry, gauging, condition monitoring and feedback control of robots

Method and apparatus for detecting and locating underwater obstacles in the path of a ship or boat. The apparatus includes a pulsed wide-angle sonar projector () controlled by a digital signal processor () that emits sound pulses at frequencies of 30 kHz and less that can penetrate sediment-laden water hundreds of meters or more ahead of the ship or boat. The projector generates echoes from submerged objects. A vector sound-intensity probe () receives the echoes and transmits them to the digital signal processor. The digital signal processor determines the location of submerged obstacles ahead of the ship or boat from the echoes received by the probe. This information is displayed on an output device (). The sonar projector and vector sound-intensity probe are contained separately in streamlined housings aimed in the forward direction under the bow of the ship or boat. The processor, output device and other electronics are located on board the ship or boat.

Forward-looking sonar for ships and boats

Method and apparatus for measuring sound intensity emitted by a vibrating surface (). The apparatus includes a probe () with three miniature microphones in the side-by-side arrangement, attached to a straight supporting tube (). The three microphones are matched in phase and amplitude and form a geometric straight line. The supporting tube () with the geometric straight line of microphones is positioned perpendicularly close to the vibrating surface (). The geometric straight line of microphones can be extended to intersect the vibrating surface at the measurement point (). The microphones are supported at the ends of narrow tubes () attached perpendicularly to the supporting tube (). The tubes contain wires from the microphones that are collected inside the supporting tube () and connected to the instrumentation (). The sign of computed sound-intensity spectra and sound intensity indicates the direction of sound-intensity flow at the vibrating surface.

Three-microphone sound-intensity probe

Method and apparatus () for measuring the sound-intensity vector in a half space bounded by a surface such as a wall or the ground () using an acoustic vector probe (AVP) (), where the AVP consists of four small omnidirectional microphones (and) supported on narrow straight tubes at the vertices of an imaginary regular tetrahedron. The tubes are attached perpendicularly to a ring () with the microphones all pointing into the half space. The sound-intensity vector measured by the AVP determines the direction of a sound source within the half space. Interference from echoes caused by reflections from the boundary of the half space and from surrounding objects on the boundary can be reduced by attaching a concave solid structure () to the base of the AVP at the supporting ring (). The inside of the concave structure is lined with absorbing material () to reduce interference by reflections from the structure.

Vector sound-intensity probes operating in a half-space

Acoustic apparatus and method for detecting and identifying near-surface buried objects using a non-contact array of ultrasonic vibrometers () each vibrometer having a focused beam in air () pointing vertically at the ground. Also there is a low-frequency loudspeaker (). Both are connected to a digital signal processor (). The loudspeaker emits continuous sound that penetrates the ground and generates echoes from a buried object, creating seismic vibrations () at the surface (). The vibrometers emit pulses of focused ultrasound with a known depth of field () and receive echo pulses () from the seismic vibrations. The pulses occur at a much faster rate than the frequency of the seismic vibrations, typically a few thousand times faster, thus permitting the processor to compute the motion and frequency content of the seismic vibrations. This data from the array determines the shape and frequency response of near-surface buried objects which are shown on a display device. The apparatus is practical and inexpensive. A movable means of scanning with the apparatus can cover the ground one section of area at a time.

Detection of bured objects using an array of non-contact ultrasonic vibrometers

A system for normalizing and calibrating the microphones of a sound-intensity probe or a composite of such probes, with respect to a stable comparison microphone with known acoustical characteristics. Normalizing and calibrating are performed using an apparatusconsisting of a tube with a loudspeaker inserted in one end and a fixture for holding the microphones of the probe together with the comparison microphone in the other end. The comparison microphone has known acoustical characteristics supplied by the manufacturer. Two banks of quarter-wave resonatorsandare attached to the side of the tube to absorb standing waves. The sound-intensity probe can be either a two-microphone probe used for measuring a single component of the sound-intensity vector or a probe with four microphones in the regular tetrahedral arrangement used for measuring the full sound-intensity vector. The microphones in the probe are made to have a substantially identical response with the comparison microphone by determining the transfer functions between the microphones and the comparison microphone. The transfer functions and known acoustical characteristics of the comparison microphone are then used to correct the pressure measurements by the microphones, when they are used to measure sound intensity. This ensures that the sound-intensity measurements are accurate and that there is essentially no bias in determining the direction to a sound source from the direction of the sound-intensity vector.

Normalization and calibration of microphones in sound-intensity probes

Method and apparatus for simultaneous acoustic measurement at a point (M) in space of the three components of the sound intensity vector. A preferred omnidirectional vector probe () includes a central ring () with four small, microphones on tubes attached to the ring spaced from one another in a regular tetrahedral arrangement. The tubes are parallel to the axis of the ring, two on one side () and two on the reverse side () of the ring, with two of the microphones pointing in one direction and two in the opposite direction. The microphone signals are processed by an analog-to-digital converter feeding a digital signal processor () and employing a cross-spectral formulation to compute a sound intensity vector at the measurement point (M). Sound velocity and pressure can also be determined at this point. The resulting data may be outputted on a computer screen or other device (). Additional related features and methods are disclosed.

Acoustic measurement method and apparatus

Method and apparatus for application of echolocation to robot guidance and assisting the blind. The method is based on the echolocation of bats. It combines a source of pulsed ultrasound () with a recently-developed acoustic vector probe (AVP) () into an echolocation instrument (), together with a data-acquisition system (), a digital signal processor () and an output device (). The source emits pulses of ultrasound of about 35 kHz over a beam angle of approximately 100 degrees and the AVP detects backscattered pulses from a discrete distribution of acoustic highlights on surrounding objects. The ultrasonic sound pressures of the backscattered pulses are heterodyned down to lower frequencies so that the signal processor can make an accurate determination of the sound-intensity vector for each pulse. The sound-intensity vector points in the direction of the highlight from which the backscattered pulse originates while the round-trip time of flight of the pulse determines the distance to the highlight. In this way the positions of the highlights on surrounding objects can be determined. The distribution of such highlights changes when the echolocation instrument moves relative to surrounding objects, generating a sequence of highlight distributions that can be stored in the memory of the processor and combined to provide a more complete representation of surrounding objects.

Method and apparatus for echolocation

Method and apparatus for locating and quantifying sound sources using an array of acoustic vector probes (). Signals received at the probes are converted to digital form and fed into a digital signal processor () which computes the sound pressure and the sound-intensity vector at each probe. The set of sound-intensity vectors measured by the array provides a set of directions to a sound source () whose approximate spatial coordinates are determined using a least-squares triangulation formula. The sound-intensity vectors also determine sound-power flow from the source. In addition sound pressure measured by the probes can be phased to form a sensitivity beam () for scanning a source. Sound-intensity measurements made concurrently can be used to determine the spatial coordinates of the part being scanned and the sound power radiated by that part. Results are displayed on a computer screen or other device () permitting an operator to interact with and control the apparatus. Additional related features and methods are disclosed.

Sound source location and quantification using arrays of vector probes

Method and apparatus for acoustic detection, location and identification of a buried object using a source emitting bursts of sound that penetrate the ground and return echoes from the object to an array of acoustic vector probes () located above the ground. Echoes recorded at the probes in the array, are converted to digital form and fed into a digital signal processor () which computes the sound-intensity vector at each probe. Results are displayed on a computer screen or other device () permitting an operator to interact with and control the apparatus. The processor controls gating of the bursts of pulsed sound and the duration of the reception of echoes by the array. Additional related features and methods are disclosed.

Method and apparatus for acoustic detection of buried objects

An acoustic sensor system for detection of insects in agricultural commodities. The system includes isolation structure for isolating the agricultural commodities from external noise and vibration, an improved acoustic sensor for detecting sound from within the agricultural commodities and for generating a signal in response to sound so detected, and a user recognizable output such as earphones or a light emitting diode for producing user recognizable output in response to signals generated by the acoustic sensor.

Acoustic sensor system for insect detection

An impact cushioning device is described for use in preventing direct contact between the terminal end portion of an elongated object and a person that may be driven toward the object for any reason. The cushioning device has application in a vehicle to protect an occupant from impacting an elongated object upon sudden deceleration of the vehicle and comprises an inflatable safety bag having a reservoir portion, a cushion portion, and an elongated inflatable duct portion which provides fluid communication between the reservoir and the cushion. The duct portion includes flow baffles and orifices for restricting free-flow of pressurized gas between the reservoir and the cushion until the duct portion is substantially fully inflated and providing a pressure gradient from the cushion to the reservoir through a period in which impact can occur. The cushion includes two complementary sections which abut each other in an axial direction when the cushion is fully inflated, in which condition the cushion engages the terminal end of the elongated object. The complementary cushion sections abut along an interface that is interlocked to prevent separation of the cushion sections in the event of impact with the cushion by an object moving axially towards the cushion. The complementary cushion sections may also have an inflatable cover portion to prevent cushion separation and provide a smoother surface for impact. The cushion is normally stowed at a position along the elongated object remote from the terminal end and, when inflated, moves over the terminal end and covers the latter.

Impact cushioning device

Valve spring assemblies are checked for proper assembly of keys by ultrasonically scanning a plurality of assemblies along a path crossing the stem, keys and cap to acquire profile data; compensating for temperature effects by determining the average time of flight to the stems, which are nominally the same distance from the ultrasonic sensor, and searching for each individual stem in a window centered on the average time of flight; then defining windows for the keys and cap offset from the measured surface of each stem; and searching the data for points within the respective windows to determine proper positioning of each element. The apparatus includes ultrasonic equipment, a scanning manipulator to move the ultrasonic sensor over the part, and a computer interfaced to the ultrasonic equipment and manipulator for control and data analysis.

Method and apparatus for ultrasonic inspection

Method and means are disclosed for stimulating combustion especially of lean mixtures in internal combustion engines. For example, an ultraviolet lamp mounted in the combustion chamber of an engine directs radiation of wavelength exceeding 190 nm on the advancing flame front. The radiation largely passes through the cool unburned mixture and is absorbed in disassociating oxygen molecules in the flame front thereby stimulating combustion of the flame and allowing the burning of exceptionally lean air-fuel mixtures. Numerous features and alternative embodiments are disclosed.

Method and means for stimulating combustion especially of lean mixtures

The bulk temperature of the gas in a piston engine during combustion is determined by detecting the high frequency pressure oscillation in the combustion chamber operating the engine to produce knock and measuring the frequency of the lowest frequency mode of the high frequency knock signal. The frequency or inversely the period of that signal is a function of the gas temperature.

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Huntington Woods, MI, United States of America

Robert Hickling