Aim To develop a high speed and high resolution dynamic rangefinding device for the measurement of large distances.Methods The device was comprised of an ultrasonic transmitter and a receiver,and a receiver , and a co...Aim To develop a high speed and high resolution dynamic rangefinding device for the measurement of large distances.Methods The device was comprised of an ultrasonic transmitter and a receiver,and a receiver , and a continuous ultrasonic wave amplitude-modulated by a low- frequency acoustic signal was used. The rangefinding was achieved by detecting the phase difference between the transmitted and received ultrasonic signals. The design principle. hard- ware implementation , experimental results and performance analysis of the device are included. Results and Conclusion Experiments show that the accuracy of the device are included. within 1.5m while its dynamic data update rate can be up to 40kHz.展开更多
Rangefinders are instruments used for ballistics and for surveying in general. Here we propose a discussion of some of them, ranging from the ancient Rome to the modern methods. Using an ancient roman artefact as a mo...Rangefinders are instruments used for ballistics and for surveying in general. Here we propose a discussion of some of them, ranging from the ancient Rome to the modern methods. Using an ancient roman artefact as a model, we can prepare a rangefinder at no cost for teaching surveying methods to students of engineering and military schools.展开更多
Till now a laser rangefinder has been used to find the range of a stationary target or the variations and deformities of a plane surface like in the manufacturing processes.New concept in the design of a laser rangefi...Till now a laser rangefinder has been used to find the range of a stationary target or the variations and deformities of a plane surface like in the manufacturing processes.New concept in the design of a laser rangefinder for a moving target is described.It is based on triangulation method of ranging and combines with a threefold false target rejection circuit to eliminate the possibility of false target indication due to light reflected by any obstruction in the line of sight of laser source and the target. The false target rejection is done twice through hardware and once through software.展开更多
Despite of good performance immunity to stress and high transmitting/receiving sensitivity advantages,the fabrication imperfection induced asynchronous vibration and the resultant prolonged ring-down tail severely lim...Despite of good performance immunity to stress and high transmitting/receiving sensitivity advantages,the fabrication imperfection induced asynchronous vibration and the resultant prolonged ring-down tail severely limit the potential of the cantilever beam-based piezoelectric micromachined ultrasonic transducer(PMUT)in pulse-echo applications as transceiver.To address this issue,a novel post processing soft interconnecting strategy is presented.In this case,specific reservoir structure is intentionally integrated into the cantilever-beam based PMUT design,under the assistance of which the liquid PDMS can be accurately applied and spontaneously driven to seal the air gaps between the already released cantilever beams via the capillary effect.After curing,the PDMS will be transformed from liquid to solid and serve as soft interconnecting spring between adjacent cantilever beams so as to force them to vibrate in synchronous mode.At the same time,this treatment does not change the existing fabrication process and has little effect on the original PMUT performance.From both of the mechanical and acoustic response measurement results,effective suppression for the asynchronous vibration and significant reduction of the ring-down tail have been successfully demonstrated for the treated PMUT device.In the subsequent pulse-echo rangefinding experiment,a distance detection range covering from 270.8 mm to 3.8 m with a divergence angle close to 170°has been achieved when it is driven at resonant frequency of 69.2 kHz with 40 Vpp,40-cycles sinusoidal signal.Given the simple yet effective treatment,the proposed strategy shows great prospective in developing high performance PMUT for in-air rangefinding applications.展开更多
文摘Aim To develop a high speed and high resolution dynamic rangefinding device for the measurement of large distances.Methods The device was comprised of an ultrasonic transmitter and a receiver,and a receiver , and a continuous ultrasonic wave amplitude-modulated by a low- frequency acoustic signal was used. The rangefinding was achieved by detecting the phase difference between the transmitted and received ultrasonic signals. The design principle. hard- ware implementation , experimental results and performance analysis of the device are included. Results and Conclusion Experiments show that the accuracy of the device are included. within 1.5m while its dynamic data update rate can be up to 40kHz.
文摘Rangefinders are instruments used for ballistics and for surveying in general. Here we propose a discussion of some of them, ranging from the ancient Rome to the modern methods. Using an ancient roman artefact as a model, we can prepare a rangefinder at no cost for teaching surveying methods to students of engineering and military schools.
文摘Till now a laser rangefinder has been used to find the range of a stationary target or the variations and deformities of a plane surface like in the manufacturing processes.New concept in the design of a laser rangefinder for a moving target is described.It is based on triangulation method of ranging and combines with a threefold false target rejection circuit to eliminate the possibility of false target indication due to light reflected by any obstruction in the line of sight of laser source and the target. The false target rejection is done twice through hardware and once through software.
基金supported by the National Natural Science Foundation of China(NSFC)(12174137)Innovation Project of Optics Valley Laboratory(Grant No.OVL2023ZD003).
文摘Despite of good performance immunity to stress and high transmitting/receiving sensitivity advantages,the fabrication imperfection induced asynchronous vibration and the resultant prolonged ring-down tail severely limit the potential of the cantilever beam-based piezoelectric micromachined ultrasonic transducer(PMUT)in pulse-echo applications as transceiver.To address this issue,a novel post processing soft interconnecting strategy is presented.In this case,specific reservoir structure is intentionally integrated into the cantilever-beam based PMUT design,under the assistance of which the liquid PDMS can be accurately applied and spontaneously driven to seal the air gaps between the already released cantilever beams via the capillary effect.After curing,the PDMS will be transformed from liquid to solid and serve as soft interconnecting spring between adjacent cantilever beams so as to force them to vibrate in synchronous mode.At the same time,this treatment does not change the existing fabrication process and has little effect on the original PMUT performance.From both of the mechanical and acoustic response measurement results,effective suppression for the asynchronous vibration and significant reduction of the ring-down tail have been successfully demonstrated for the treated PMUT device.In the subsequent pulse-echo rangefinding experiment,a distance detection range covering from 270.8 mm to 3.8 m with a divergence angle close to 170°has been achieved when it is driven at resonant frequency of 69.2 kHz with 40 Vpp,40-cycles sinusoidal signal.Given the simple yet effective treatment,the proposed strategy shows great prospective in developing high performance PMUT for in-air rangefinding applications.
