High resolution (0.2 mm) and fast response (2 ms) range finder for industrial use in air

Teshigawara, Masaki; Shibata, F.; Teramoto, Hitoshi

doi:10.1109/ultsym.1989.67062

Cited by 9 publications

(2 citation statements)

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“…An ultrasonic sensor system was selected to provide information to a wheelchair controller. Ultrasonic range-finding and object-detection systems have used several principles, including: modulated waves (Teshigawara et al, 1989), frequency sweeps (Lindstedt, 1996) or echolocation (Stott and Sanders, 1996;Stott et al, 1997). Kay used a novel sensor array and constant transmission frequency modulation (CTFM) sweeps to assist blind people in detecting their environment (Kay, 1999b).…”

Section: Ultrasonic Sensingmentioning

confidence: 99%

Low cost ultrasonic sensors for tele‐operated vehicles

Stott

Sanders²,

Tewkesbury³

2000

Sensor Review

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Describes a new reliable low‐cost ultrasonic ranging system to assist in steering a powered wheelchair. Detection algorithms have been created and implemented on a micro controller based stand‐alone system suitable for a tele‐operated vehicle. The detection uses the gradient of the echo envelope and is resistant to noise and inconsistencies in the detection circuitry. The sensor array was considered as separate sensors, working independently so the system could quickly gather separate sets of range information. These sets were overlaid on to a 2D grid array. The new system is cheaper and simpler than available systems for powered wheelchairs.

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Section: Ultrasonic Sensingmentioning

confidence: 99%

Low cost ultrasonic sensors for tele‐operated vehicles

Stott

Sanders²,

Tewkesbury³

2000

Sensor Review

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“…There are two basic designs. The first includes those that use conventional piezoelectric ceramic materials, either unmodified [9] or as a 1-3 connectivity composite [10]. In the latter case, waves generated in a range of materials were detected in through-transmission studies.…”

Section: Types Of Detectorsmentioning

confidence: 99%

Pulsed Lasers for Quantitative Ultrasonic NDE

Hutchins

1992

Review of Progress in Quantitative Nondestructive Evaluation

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There has been a lot of recent interest in the use of pulsed lasers for the generation of ultrasound in a range of media [1], due to advantages inherent in the generation process. These include the non-contact nature of the method, and the generation of a wide bandwidth over a small source area. The size and shape of the source can also be changed using suitable optics, as can the generation mechanism itself. Generation MechanismsIn general, there are three types of source characteristics that are available. The first uses optical power densities that are below that required for melting of the irradiated solid surface. This results in a transient heating of the substrate, leading to rapid thermal expansion and the radiation of elastic waves. This is the so-called thermoelastic effect and the resulting waveforms and characteristics have been studied widely [e.g. 2,3]. The second type of generation mechanism can be created by removal of material from the surface of the sample. This can be by evaporation of a coating, applied to the surface prior to irradiation, or the ablation of the material itself [4]. In either case, the effect is to create a force due to material departing from the surface. This force tends to be pulse-like, unlike the thermoelastic ca se where the incoming laser energy is integrated to become a step. Where an applied coating is absent, a mixture of these two mechanisms can lead to a range of waveforms and source characteristics, as the power density at the surface is varied. This is due primarily to the formation of a plasma elose to the surface of e.g. a metal, which prolongs ablation at higher power densities.A third mechanism has recently been identified, which uses the effect of plasma formation close to a surface, but not intimately connected to it as in the ca se of a metal above. This occurs when there is a relatively high optical reflectivity, such as is present with far infra-red laser radiation (e.g. a C02 laser). Here, the reflected energy and incidence pulse can combine to induce breakdown of the air close to the surface, but at some distance from it [5] . Types of DetectorsIt is evident from the above that a pulsed laser can be a flexible method for the NDE of many materials. However, for it to be a truly useful method, it needs to be combined with adeteetion system that is itself non-contact and whieh has a wide bandwidth. The most popular recent choice for detection has been interferometry. This is also an optieally-based approach, and leads to good detection sensitivity at a wide range of surfaces. The types of interferometers available have been reviewed by Monchalin [6], and there are now several devices available commercially. Recent advances in both heterodyne and Fabry-Perot designs now give good detection sensitivity, and with a pulsed laser source can lead to an NDE system that is capable of inspecting industrial materials [7]. Interferometry has severallimitations -it tends to be expensive, and requires a certain reflectivity at the deteetion surface. Despite these li...

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Ultrasonic digital measuring methods

Kočiš

Figura²

1996

Ultrasonic Measurements and Technologies

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High resolution (0.2 mm) and fast response (2 ms) range finder for industrial use in air

Cited by 9 publications

References 0 publications

Low cost ultrasonic sensors for tele‐operated vehicles

Low cost ultrasonic sensors for tele‐operated vehicles

Pulsed Lasers for Quantitative Ultrasonic NDE

Ultrasonic digital measuring methods

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