Free-flight measurement technique in the free-piston high-enthalpy shock tunnel

Tanno, Hideyuki; Komuro, Tomoyuki; Sato, K.; Fujita, Kazuhisa; Laurence, Stuart J.

doi:10.1063/1.4870920

Cited by 24 publications

(4 citation statements)

References 13 publications

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“…Nevertheless, the model injection system and umbilicals may have produced aerodynamic interference, and such interference would become mostly undesirable when pitching moment measurements are required. A new free-flight technique was developed to keep the resolution and avoid the interferences using specially designed model-onboard data recording systems (Tanno et al 2014). Since the test model is in free-fall during the test duration resulting in an entirely unconstrained motion, aerodynamic interference and mechanical vibration are eliminated.…”

Section: Free-flight Technique In Short Test Durationmentioning

confidence: 99%

“…An onboard miniature data recorder is the critical technology for the present free-flight onboard measurements. In this study, two JAXA original data recorders (Tanno et al 2014) were onboard in MoDKI, which records at a sampling rate of 500 kHz with a 16-bit resolution. A total of 16 channels were used, 8 each for piezoelectric sensors (accelerometers) and piezoresistive sensors (pressure transducers).…”

Section: Onboard Sensors and Data Recordersmentioning

confidence: 99%

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Aerodynamic characteristics of a free-flight scramjet vehicle in shock tunnel

Marie

Tanno

2021

Exp Fluids

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A multi-component aerodynamic test for an airframe-engine integrated scramjet vehicle model was conducted in the free-piston shock tunnel HIEST. A free-flight force measurement technique was applied to the scramjet vehicle model named MoDKI. A new method using multiple piezoelectric accelerometers was developed based on overdetermined system analysis. Its unique features are the following: (1) The accelerometer’s mounting location can be more flexible. (2) The measurement precision is predicted to be improved by increasing the number of accelerometers. (3) The angular acceleration can be obtained with single-axis translational accelerometers instead of gyroscopes. (4) Through the averaging process of the multiple accelerometers, model natural vibration is expected to be mitigated. With eight model-onboard single-axis accelerometers, the three-component aerodynamic coefficients (Drag, Lift, and Pitching moment) of MoDKI were successfully measured at the angle of attack from 0.7 to 3.4 degrees under a Mach 8 free-stream test flow condition. A linear regression fitting revealed a 95% prediction interval as the measurement precision of each aerodynamic coefficient. Graphical abstract

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Section: Free-flight Technique In Short Test Durationmentioning

confidence: 99%

Section: Onboard Sensors and Data Recordersmentioning

confidence: 99%

Aerodynamic characteristics of a free-flight scramjet vehicle in shock tunnel

Marie

Tanno

2021

Exp Fluids

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“…Another example is magnetic suspension wind tunnel balance [18].The magnetic suspension balance system [19] [20] benefits from its structure without physical supports, and the model being supported with levitation control system is an effective method to study the aerodynamic characteristics of the model, because the system can support the model without interfering with the test flow field, and can control the attitude of the model freely. Magnetic suspension balances use electromagnetic force to support models containing permanent magnets, so as to measure the aerodynamics of the aircraft without mechanical contact hanging in the wind tunnel [21] [22]. There is also vibration and instability in the magnetic suspension balance that is the same as the maglev train.…”

Section: Introductionmentioning

confidence: 99%

Disturbance Rejection Control Using a Novel Velocity Fusion Estimation Method for Levitation Control Systems

Xia

Dou

2020

IEEE Access

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Magnetic levitation has been applied to maglev trains and magnetic suspension wind tunnel. However, there are some problems with the existing levitation control. For example, it is difficult to extract smooth velocity signals from the gap sensor with noise. The classical differentiator is susceptible to noise, which makes the levitation system sometimes vibrate. The accuracy and stability of levitation control need to be improved. The velocity fusion estimation method (VFE) is proposed to extract the velocity signal from the gap and acceleration sensor, which is theoretically derived to prove that it reduced the noise of the velocity signal. Then disturbance rejection control(DRC) is proposed that add VFE into classical levitation control. Because of the high-quality velocity signal and accelerometer's fast responsiveness, it makes DRC have many advantages. The advantages of using the proposed control structure are that it improved the control accuracy of the target gap and resisted disturbance effectively. Air-gap fluctuations in levitation systems can be reduced in transient pulse disturbance test, white noise disturbance test, and external force disturbance test when it applies the proposed control method. The effectiveness and advantages of the proposed control method are verified by the simulation and experiments.

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“…The higher the natural frequencies are, the better the justification for the neglected acceleration compensation. For these test conditions, many researchers have proposed several special balances to measure the aerodynamic forces in impulse facilities-i.e., the accelerometer balance [5][6][7], the stress-wave force balance [8][9][10], the free-flight measurement technique [11][12][13][14][15], the compensated balance [16], and the impulse-type strain gauge balance (SGB) [17,18]. Owing to the very short test time, however, mature technology has not been developed for the force measurement in a shock tunnel.…”

Section: Introductionmentioning

confidence: 99%

Intelligent Force-Measurement System Use in Shock Tunnel

Wang

Jiang

2020

Sensors

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The inertial vibration of the force measurement system (FMS) has a large influence on the force measuring result of aircraft, especially on some tests carried out in high-enthalpy impulse facilities, such as in a shock tunnel. When force tests are conducted in a shock tunnel, the low-frequency vibrations of the FMS and its motion cannot be addressed through digital filtering because of the inertial forces, which are caused by the impact flow during the starting process of the shock tunnel. Therefore, this paper focuses on the dynamic characteristics of the performance of the FMS. A new method—i.e., deep-learning-based single-vector dynamic self-calibration (DL-based SV-DSC) of an impulse FMS, is proposed to increase the accuracy of aerodynamic force measurements in a shock tunnel. A deep-learning technique is used to train the dynamic model of the FMS in this study. Convolutional neural networks with a simple structure are applied to describe the dynamic modeling so that the low-frequency vibration signals are eliminated from the test results of the shock tunnel. By validation of the force test results measured in a shock tunnel, the current trained model can realize intelligent processing of the balance signals of the FMS. Based on this new method of dynamic calibration, the reliability and accuracy of force data processing are well verified.

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Free-flight measurement technique in the free-piston high-enthalpy shock tunnel

Cited by 24 publications

References 13 publications

Aerodynamic characteristics of a free-flight scramjet vehicle in shock tunnel

Aerodynamic characteristics of a free-flight scramjet vehicle in shock tunnel

Disturbance Rejection Control Using a Novel Velocity Fusion Estimation Method for Levitation Control Systems

Intelligent Force-Measurement System Use in Shock Tunnel

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