scholarly journals Nonlinear L1 adaptive control of stagnation pressure in a cryogenic wind tunnel

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Rusong Zhu ◽  
Mingwei Xie ◽  
Daxiong Liao ◽  
Gengsheng Tang ◽  
Wen Gai
Keyword(s):  
Adaptive Control ◽  
Mach Number ◽  
Wind Tunnel ◽  
Nonlinear Systems ◽  
Feedforward Control ◽  
Pressure Control ◽  
Stagnation Pressure ◽  
Control Architecture ◽  
Adaptive Feedforward ◽  
Cryogenic Wind Tunnel

AbstractCryogenic wind tunnel is a sophisticated aerodynamics ground test facility, which operates in cryogenic temperature with injection of liquid nitrogen. The multi-variable, nonlinear and coupled dynamics existing between the temperature, pressure and Mach number in the tunnel, poses great challenges for the effective control of the tunnel. L1 adaptive control is a new control methodology developed in recent years with good robustness properties, which has good potentials to address these challenges. But this control method does not provide full adaptive feedforward control in its generic structure. In the paper, adaptive feedforward control action is introduced into the standard L1 adaptive control architecture for nonlinear systems in the presence of matched un-modeled dynamics. This new control structure is applied to the stagnation pressure control in a cryogenic wind tunnel, which could also be used for the control of temperature and Mach number in the tunnel. This new method could effectively compensate known disturbances with linear gain uncertainty, which occur in the nonlinear systems, while retaining the closed-loop control performance of L1 adaptive control. After the proof and discussions on the stability of this method, simulations of the stagnation pressure control in the wind tunnel are presented. The results and analysis demonstrate the effectiveness of the proposed control architecture.

scholarly journals Prediction of total pressure characteristics in the settling chamber of a supersonic blowdown wind tunnel

2011 ◽  
Vol 115 (1171) ◽  
pp. 557-566 ◽  
Author(s):  
G. K. Suryanarayana ◽  
S. R. Bhoi
Keyword(s):  
Mach Number ◽  
Wind Tunnel ◽  
Storage Tank ◽  
Stagnation Pressure ◽  
Rate Of Change ◽  
Settling Chamber ◽  
Low Mach Number ◽  
High Mach ◽  
And Storage ◽  
Pressure Characteristics

Abstract Occurrence of transient starting and stopping loads during tests at high Mach numbers is one of the major problems in intermittent blowdown wind tunnels. It is believed that in order to overcome this problem, the wind tunnel could be started at a low Mach number and low stagnation pressure; the desired high Mach number condition could be reached by continuously changing the nozzle contour while synchronously increasing the stagnation pressure. After completing the tests, the nozzle could be brought back to the initial low Mach number accompanied by synchronous decrease in the stagnation pressure. In such a scenario, it is important to ensure that the pressure regulating valve (PRV) of the wind tunnel delivers and maintains a specified minimum stagnation pressure at any Mach number, so that supersonic breakdown of the test section flow does not occur. In this paper, the problem is formulated based on quasi-steady one-dimensional isentropic equations and numerically solved to predict the time histories of settling chamber pressure and storage tank pressure for a given trajectory of the opening of the PRV, as the Mach number is changed from Mach 1 to 4·0 continuously in four seconds and vice versa. The effects of rate of change of PRV open area and rate of change of Mach number on the stagnation pressure characteristics in the settling chamber and storage tank are predicted. The measured trajectories of the PRV in experiments in the NAL 0·6m transonic wind tunnel are used as input to the prediction program to validate the methodology. Predictions indicate that when the nozzle throat is changed from Mach 1 to 4 in four seconds, the settling chamber stagnation pressure rapidly builds up and approaches the pressure in the storage tank. Predictions show an alarming rise in free stream dynamic pressure during transition from Mach 1 to 4 and vice versa, which needs to be verified through measurements.

scholarly journals Model-based stagnation pressure control in a supersonic wind tunnel

2016 ◽  
Vol 44 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Biljana Ilić ◽  
Marko Miloš ◽  
Mirko Milosavljević ◽  
Jovan Isaković
Keyword(s):  
Wind Tunnel ◽  
Pressure Control ◽  
Stagnation Pressure ◽  
Supersonic Wind Tunnel ◽  
Model Based

Dynamic feedforward control for Mach number in wind tunnel

2021 ◽  
Author(s):  
Wenshan Yu ◽  
Ming Zhang ◽  
Zhengzhou Rao ◽  
Zhi Wei ◽  
Gang Liu
Keyword(s):  
Mach Number ◽  
Wind Tunnel ◽  
Feedforward Control

Temperature trajectory control of cryogenic wind tunnel with robust L1 adaptive control

2017 ◽  
Vol 40 (13) ◽  
pp. 3675-3689 ◽  
Author(s):  
Rusong Zhu ◽  
Guofu Yin ◽  
Gengsheng Tang ◽  
Hai Wang ◽  
Shuangxi Zhang
Keyword(s):  
Adaptive Control ◽  
Wind Tunnel ◽  
Temperature Control ◽  
Adaptive Controller ◽  
Linear Temperature ◽  
L1 Adaptive Control ◽  
State Dependent ◽  
Non Linear ◽  
Linear State ◽  
Cryogenic Wind Tunnel

Temperature control in a cryogenic wind tunnel is the key to realizing finely controlled Reynolds number close to true flight. This study deploys the L1 adaptive control methodology to ensure the total temperature profile of the cryogenic wind tunnel tracks a specified reference trajectory. After introducing a non-linear model of a cryogenic wind tunnel and a linear temperature model, a linear–quadratic–Gaussian (LQG) controller is implemented as the baseline controller. The L1 adaptive controller with piecewise constant adaptive law is used as an augmentation to the baseline controller to cancel the matched and unmatched uncertainties within the actuator’s bandwidth. By introducing two modifications to the standard L1 adaptive controller, which are the transportation delay modelling in the state predictor and the non-linear state dependent filter, the L1 adaptive controller improves the performance of the baseline controller in the presence of uncertainties in temperature control, guaranteeing proper stability and delay margin. The simulation results and analysis demonstrate the effectiveness of the proposed control architecture. The main contribution of this paper lies in the first applications of L1 adaptive control to the wind tunnel control problem and the non-linear state dependent filter in L1 adaptive control structure.

Adaptive Control of Structural Acoustics using Intelligent Structures with Embedded Piezoelectric Patches

2003 ◽  
Vol 9 (11) ◽  
pp. 1285-1302
Author(s):  
Kougen Ma ◽  
J Melcher
Keyword(s):  
Adaptive Control ◽  
Digital Signal Processor ◽  
Feedforward Control ◽  
Low Cost ◽  
Digital Signal ◽  
Structural Acoustics ◽  
Intelligent Structures ◽  
Control Scheme ◽  
Hybrid Adaptive Control ◽  
Adaptive Feedforward

In this paper we focus on the adaptive control of structural acoustics using intelligent structures with embedded piezoelectric (PZT) patches and low cost digital signal processor systems. After a discussion on the adaptive feedforward control scheme, a hybrid adaptive control scheme is proposed, which takes advantage of both feedback control and adaptive feedforward control. The two schemes are realized on a low-cost, small volume, convenient and universal digital signal processing (DSP) board. A carbon fiber reinforced polymer plate with two embedded PZT patches is developed and used in two experiments. The first experiment is adaptive interior noise control using the intelligent plate, in which the adaptive feedforward control scheme is employed. Obvious noise reduction is obtained for constant frequency, swept frequency and varying amplitude harmonic disturbances. The second experiment is adaptive control of sound-induced vibration of the plate, where two embedded PZT patches are used as an actuator and a sensor, respectively, and the hybrid adaptive controller is applied. The full vibration reduction for various harmonic excitations is obtained, verifying the advantage of the hybrid adaptive control. It is demonstrated that active control of structural acoustics can be efficiently achieved by employing intelligent structures, advanced adaptive control schemes and the low-cost DSP board.

The Ludwieg Pressure-Tube Supersonic Wind Tunnel

1963 ◽  
Vol 14 (2) ◽  
pp. 143-157 ◽  
Author(s):  
A. J. Cable ◽  
R. N. Cox
Keyword(s):  
Mach Number ◽  
Wind Tunnel ◽  
Nozzle Exit ◽  
High Speed ◽  
Layer Growth ◽  
Stagnation Pressure ◽  
Pressure Tube ◽  
Rarefaction Waves ◽  
Supersonic Wind Tunnel ◽  
Blow Down

SummaryA description is given of a supersonic pressure-tube wind tunnel which has been constructed at A.R.D.E. This is a blow-down tunnel which uses as a reservoir a long tube filled with gas under pressure. A quasi-steady supersonic flow is achieved by expanding in a convergent-divergent nozzle the subsonic flow behind rarefaction waves which propagate down the tube when a diaphragm at the nozzle exit is burst. The theory of the operation of the tunnel is given and calculations are made of the boundary-layer growth along the tube. Pressure-time records were obtained in the tube, and a high speed camera was used to obtain pictures of the flow round a model. Measurements also included a pitot-tube traverse of the nozzle exit, and the Mach number distribution was determined from the ratio of the pitot to the stagnation pressure. Tests showed that, as predicted, a constant stagnation pressure was obtained ahead of the nozzle, and it is considered that a tunnel of this type would be a cheap and simple way of obtaining an intermittent tunnel with adequate running time for many types of test, and capable of operating at a Reynolds number of more than 107 per inch at a Mach number of about 3·5.

scholarly journals Temperature control of cryogenic wind tunnel with a modified L1 adaptive output feedback control

2018 ◽  
Vol 51 (9-10) ◽  
pp. 498-513 ◽  
Author(s):  
Rusong Zhu ◽  
Guofu Yin ◽  
Zhenhua Chen ◽  
Shuangxi Zhang ◽  
Zili Guo
Keyword(s):  
Adaptive Control ◽  
Temperature Control ◽  
Output Feedback ◽  
Feedforward Control ◽  
Adaptive Controller ◽  
Linear Quadratic ◽  
Linear Quadratic Gaussian ◽  
L1 Adaptive Control ◽  
Adaptive Law ◽  
Cryogenic Wind Tunnel

Background: Temperature is one of the main variables need to be regulated in cryogenic wind tunnel to realize the true flight Reynolds number. A new control methodology based on L1 output feedback adaptive control is deployed in the temperature control. Methods: This design is composed of three parts: linear quadratic Gaussian baseline control, L1 adaptive control and nonlinear feedforward control. A linear quadratic Gaussian controller is implemented as the baseline controller to provide the basic robustness of temperature control. A L1 output feedback adaptive controller with a modified piecewise constant adaptive law is deployed as an augmentation for the baseline controller to cancel the uncertainties within the actuator’s bandwidth. The modified adaptive law can guarantee better steady-state tracking performance compared with the standard adaptive law. A global nonlinear optimization process is carried out to obtain a suboptimal filter design for the L1 controller to maximize the performance index. The nonlinear feedforward control is to cancel the coupling effects in control of the tunnel. Results: With these design techniques, the augmented L1 adaptive controller improves the performance of the baseline controller in the presence of uncertainties of dynamics. The simulation results and analysis demonstrate the effectiveness of the proposed control architecture. Conclusion: The modification of adaptive law plus the global nonlinear optimization of the filter in the L1 adaptive control architecture helps the controller achieve good control performance and acceptable robustness for the temperature control over a wide range of operations.

scholarly journals Summarisation, Simulation and Comparison of Nine Control Algorithms for an Active Control Mount with an Oscillating Coil Actuator

Algorithms ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 256 ◽  
Author(s):  
Rang-Lin Fan ◽  
Pu Wang ◽  
Chen Han ◽  
Li-Jun Wei ◽  
Zi-Jian Liu ◽  
...  
Keyword(s):  
Adaptive Control ◽  
Active Control ◽  
Control Algorithm ◽  
Vibration Isolation ◽  
Feedforward Control ◽  
Operating Conditions ◽  
Control Algorithms ◽  
Force Transmission ◽  
Fuzzy Pid Control ◽  
Adaptive Feedforward

With the further development of the automotive industry, the traditional vibration isolation method is difficult to meet the requirements for wide frequency bands under multiple operating conditions, the active control mount (ACM) is gradually paid attentions, and the control algorithm plays a decisive role. In this paper, the ACM with oscillating coil actuator (OCA) is taken as the object, and the comparative study of the control algorithms is performed to select the optimal one for ACM. Through the modelling of ACM, the design of controller and the system simulations, the force transmission rate is used to compare the vibration isolation performance of the nine control algorithms, which are least mean square (LMS) adaptive feedforward control, recursive least square (RLS) adaptive feedforward control, filtered reference signal LMS (FxLMS) adaptive control, linear quadratic regulator (LQR) optimal control, H2 control, H∞ control, proportional integral derivative (PID) feedback control, fuzzy control and fuzzy PID control. In summary, the FxLMS adaptive control algorithm has the better performance and the advantage of easier hardware implementation, and it can apply in ACMs.

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