Vision measurement technique of model position and its widespread application on the ballistic range

Ke, Fa-wei; Huang, Jie; Li, Xin; Song, Qiang; Xie, Ai-Gen; Jian, Huang; Wen, Xin; Wang, Zonghao; Liu, Sen

doi:10.1016/j.measurement.2019.03.058

Cited by 3 publications

(2 citation statements)

References 11 publications

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“…The two configurations of the scaled models are shown in Figure 1. When the flying model with coded marking points on surface entered the measurement field, it would be illuminated by the extended laser beam with the pulse width of smaller than 10 ns; meanwhile, the two images of the target were obtained by the cameras [11]. Mass properties are shown in Table 1.…”

Section: Test Descriptionmentioning

confidence: 99%

Ballistic Range Testing Data Analysis of Tianwen-1 Mars Entry Capsule

Wei

Huang

et al. 2021

Space Sci Technol

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A typical blunt body such as Tianwen-1 Mars entry capsule suffers dynamic instability in supersonic regime. To investigate the unstable Mach range of flight and to confirm the design of aerodynamic shape and mass properties, a ballistic range test was carried out aiming at capturing supersonic dynamic characteristics of Tianwen-1. Aerodynamic coefficients of free-flight scaled models were derived by modified linear regression method based on position and attitude data, while the dynamic coefficients were established under the assumption of small angle linearization. The static moment coefficients and dynamic derivatives were identified thereafter. Results show that models in untrimmed configuration are dynamically unstable at certain Mach numbers, whereas models in trimmed configuration are dynamically stable at other Mach numbers tested. Both trimmed and untrimmed configurations are statically stable in all testing cases.

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Section: Test Descriptionmentioning

confidence: 99%

Ballistic Range Testing Data Analysis of Tianwen-1 Mars Entry Capsule

Wei

Huang

et al. 2021

Space Sci Technol

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“…This paper was based on the research into the parallel illumination of a high-power infrared narrow-pulse laser, the signal trigger, the sequential control, and the reception of the image sensor. We proposed a method based on high-speed shadow imaging to obtain the image of the projectile's position when the LSVM system generates the timing signal [18][19][20][21][22], which uses the image processing to obtain the target deviation of the projectile relative to the light screen, thereby correcting the target distance of the LSVM system. It is intended to measure and calibrate the consistency of the optoelectronic response of the LSVM system by the proposed method, and improve the measuring accuracy of the projectile's velocity.…”

Section: Introductionmentioning

confidence: 99%

Research on Target Deviation Measurement of Projectile Based on Shadow Imaging Method in Laser Screen Velocity Measuring System

Chu

Zhao

Liu

et al. 2020

Sensors

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In the laser screen velocity measuring (LSVM) system, there is a deviation in the consistency of the optoelectronic response between the start light screen and the stop light screen. When the projectile passes through the light screen, the projectile’s over-target position, at which the timing pulse of the LSVM system is triggered, deviates from the actual position of the light screen (i.e., the target deviation). Therefore, it brings errors to the measurement of the projectile’s velocity, which has become a bottleneck, affecting the construction of a higher precision optoelectronic velocity measuring system. To solve this problem, this paper proposes a method based on high-speed shadow imaging to measure the projectile’s target deviation, ΔS, when the LSVM system triggers the timing pulse. The infrared pulse laser is collimated by the combination of the aspherical lens to form a parallel laser source that is used as the light source of the system. When the projectile passes through the light screen, the projectile’s over-target signal is processed by the specially designed trigger circuit. It uses the rising and falling edges of this signal to trigger the camera and pulsed laser source, respectively, to ensure that the projectile’s over-target image is adequately exposed. By capturing the images of the light screen of the LSVM system and the over-target projectile separately, this method of image edge detection was used to calculate the target deviation, and this value was used to correct the target distance of the LSVM to improve the accuracy of the measurement of the projectile’s velocity.

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