Utility model content
The purpose of this utility model is to provide a kind of device measuring aircraft three-freedom moving steadiness parameter in high-speed wind tunnel.
The technical scheme in the invention for solving the technical problem is: the device measuring aircraft three-freedom moving steadiness parameter in high-speed wind tunnel, it is characterized in that, it comprises pitch vibration cylinder, cartridge type balance, pitching vibrator, the first and second driftage/rolling vibrators, tee T pole, framework, the first and second connecting rods, slide bar, support sting, dummy vehicle, rear end elastic hinge, middle part elastic hinge, front end elastic hinge, pitching elastic hinge, driftage elastic hinge, rolling elastic hinge, roll sensor etc.
Pitching exciting piezoelectric actuator group is provided with in described support sting, described pitching exciting piezoelectric actuator group is connected with the rear end elastic hinge of first connecting rod after being joined by frame set, the middle part of described first connecting rod is connected with the middle part elastic hinge on support sting, the front end of described first connecting rod is connected by front end elastic hinge with vibrating barrel, and described vibrating barrel is connected by pitching elastic hinge with support sting;
Further, tee T pole is provided with in the inner chamber of described pitch vibration cylinder, the two ends of the upper vertical axes of described tee T pole are connected by elastic hinge of going off course with vibrating barrel, and the two ends of the upper transverse axis of described tee T pole are connected by rolling elastic hinge with cartridge type balance;
Further, the first driftage/rolling piezoelectric actuator and the second driftage/rolling piezoelectric actuator is provided with in described cartridge type balance, one end of first, second driftage/rolling piezoelectric actuator is fixed on vibrating barrel, the other end of first, second driftage/rolling piezoelectric actuator connects with corresponding second connecting rod elastic hinge respectively, and second connecting rod described in two is all connected by elastic hinge with cartridge type balance;
Further, the flexure strip of the elastic hinge of described vibrating barrel and support sting is provided with foil gauge, in order to measure the change of the angle of pitch, in described cartridge type balance, the front end of tee T pole is provided with flexure strip, which is provided with the foil gauge of reaction roll angle, the flexure strip of the driftage elastic hinge be connected with vibrating barrel at the upper and lower end of tee T pole also there is foil gauge, to measure the change of crab angle.
Further, first, second driftage/rolling piezoelectric actuator is fixed with guide rail end block, described support sting is provided with guide rod, described guide rod and guide rail end block are slidably connected.
Further, described cartridge type balance is thin-wall construction.
The beneficial effects of the utility model are: the device measuring aircraft three-freedom moving steadiness parameter in the high-speed wind tunnel that the utility model provides, use the mode of two-stage motion platform: the pitch vibration in the pitch plane of the relative support sting of vibrating barrel, the vibration of driftage and rolling done by balance Relative Vibration cylinder.The driftage of model and roll oscillation axle and pitch vibration axle keep orthogonality relation forever, thus make model be obtained three-degree-of-freedom motion around three Z-axises; The joint of all moving components is all connected by elastic hinge; Thin-walled boxlike five COMPONENT BALANCE provides high rigidity, high sensitivity and large inside installing space.The utility model is placed in wind-tunnel, accurately can measure aircraft three-freedom moving steadiness parameter in high-speed wind tunnel.
Embodiment
Below in conjunction with accompanying drawing, the utility model is described in detail.
As shown in Fig. 1 to Fig. 7, install dummy vehicle 110 in the front end of cartridge type balance, the pitching exciting piezoelectric actuator group 102 be arranged in support sting 101 promotes the axle center pitch vibration of first connecting rod 108 around the first cross hinge 105 by yi word pattern hinge 104 after framework 103 groups connection.First connecting rod front end premenstrual yi word pattern hinge 106 is connected with vibrating barrel 114 and promotes the axle center pitch vibration of the second cross hinge 107 that vibrating barrel 114 is connected with support sting along vibrating barrel.Like this, when the upper and lower straight-line oscillation of piezoelectric actuator, first connecting rod can make pitch vibration by the rotation center in the middle part of first connecting rod.Circular arc is compensated to the radial difference of rectilinear motion by the lateral flexibility of yi word pattern hinge.When the pitching amplitude 1.5 degree of vibrating barrel, on connecting rod, the brachium of pitch vibration is 100 millimeters, and this radial variations is only 0.021 millimeter.Under such lateral deformation, although yi word pattern hinge bears the drawing of 1125 newton, compressive load, it is still in the scope allowed band of pressure bar stabilization.
A tee T pole 115 is had in vibrating barrel, the upper and lower side of the Z-axis of tee T pole is connected with vibrating barrel through cross hinge, and after the transverse axis of tee T pole having T-shaped bar, before cross hinge 118, T-shaped bar, cross hinge 119 is connected with cartridge type balance 109.Like this, cartridge type balance can make yaw oscillation around the upper and lower cross hinge Relative Vibration cylinder of the Z-axis of tee T pole.Cartridge type balance also can make roll oscillation by the cross hinge Relative Vibration cylinder on the transverse axis of tee T pole.
Parallelly in cartridge type balance placed two piezoelectric actuators, be respectively the first driftage/rolling piezoelectric actuator 120 and the second driftage/rolling piezoelectric actuator 121, the direction of placement is orthogonal with pitch orientation.In addition, one end of these two piezoelectric actuators is fixed on vibrating barrel, and the other end is connected with respective second connecting rod 122, and is connected with cartridge type balance through elastic hinge 123.Here, effect and the aforesaid yi word pattern hinge of elastic hinge are similar, and only its lateral deformation is the lateral deformation sum that second connecting rod and balance circular motion cause.If balance pivoted arm is 20 millimeters, this lateral deformation is 0.012 millimeter to the maximum, within the pressure bar stabilization scope of a word slice.
In addition, in order to make vibrator can accurately Linear Driving, avoid the impact of side load, support sting has the guide rod 124 of vertical movement, the guide hole on the guide rail end block 125 of the moved end (top) of this guide rod and vibrator have employed the form be slidably matched.Like this, just ensure that the upper and lower accurately rectilinear motion with vibrator.
By above-mentioned arrangement, these two piezoelectric actuators both can order about that balance Relative Vibration cylinder is gone off course, roll oscillation, can order about again the combination vibration that balance Relative Vibration cylinder does driftage and rolling.
On the second cross hinge 107, foil gauge is posted in the appropriate location of spoke, and forms Wheatstone bridge, to reflect the instantaneous corner course of balance relative to the driftage of pole.In cartridge type balance 109, the front end of tee T pole 115, have the flexure strip 126 of a reaction roll angle, be connected with tee T pole 115 with cartridge type balance 109 respectively, be stained with the foil gauge of reflection model roll angle above.
Cartridge type balance 109 can be five COMPONENT BALANCE, in order to meet the requirement that longitudinal loading is comparatively large and side load is less, cartridge type balance there are three cover load-sensing unit groups, i.e. pitching power and normal force load-sensing unit 133, yawing and side force load-sensing unit 134 and rolling load-sensing unit 135, correspondingly respectively to measure longitudinally, side direction and rolling aerodynamic loading.Each element component is not made up of four post beam type composition elements on two different cross sections.Respective side is larger than the distances surveying longitudinal load-sensing unit with the distance between cross section to two of load-sensing unit, to meet the requirement of balance to side load and the different sensitivity to longitudinal loading.Cartridge type balance 109 is also provided with pitching tommy 130, driftage tommy 131 and balance inner cone 132.
At pitching moment M
zwith yawing M
yunder effect, the stress and strain of cross section I and cross section II is calculated by following formula respectively:
To pitching moment M
z,
To yawing M
y,
To rolling moment M
x,
Due to structural limitations, two cross sections of cartridge type balance 109 can not be across the both sides of model rotation center (the second cross hinge 107), can only try one's best near the rotation center of model.Appropriate location on the strain beam of cartridge type balance 109 is posted foil gauge and forms electric bridge, measures instantaneous normal direction, side force and pitching, driftage, rolling moment, input store and computing machine respectively.
In order to reduce the impact of the measuring error such as gas, the load signal that when the model angular displacement signal that hinge exports and blowing, cartridge type balance 109 exports, after the parameter identification of cross correlation process and three period equations, provides relevant quiet, dynamic Aerodynamic Coefficient.
Balance input (i.e. main motion signal) is X (t)=P
0sin ω t
Balance exports as Y (t)=S
0sin (ω t+ η)+n (t)
If noise is uncorrelated with main motion, then above formula can be write as
Equally, if the average that X (k) and Y (k) is wide steady each state Pianli is the departure process of zero, then the cross correlation function of sequence X (k) and Y (k) is
R
xy(l)=E{X(k)Y(k+l)}
Corresponding estimator or sample this cross correlation function and be
l=0,±1,±2,…,±(L-1)
L is data length
During data processing, first should deduct the mean value of each signal, to eliminate constant term, then carry out related operation.Wherein sampling interval, total number of samples, maximum delayed several L etc., determine according to factors such as test frequency, signal to noise ratio, permissible accuracy and system passbands.
When Three Degree Of Freedom vibration done by model, Dynamic stability parameter will be tried to achieve through the modulus identification of three periodic motions:
When model is around center of gravity three-degree-of-freedom motion, three cyclical theorys of the available description precession of motion of model, nutating and rolling movement describe:
Introduce multiple dihedral formula
ξ=iα+β
Above-mentioned equation can be written as after simplifying:
Solution of equation can be written as
In formula, the right three parts are nutating precession, precession and rolling three mode.Wherein k
1, k
2, k
3for plural number, above formula being written as two real variable forms has
A in above formula
1, B
1, A
2, B
2be and starting condition α
0,
β
0,
relevant constant.Frequency leads and damping term ω
1, ω
2, λ
1, λ
2be and remove M
δthe parameter that aerodynamic parameter to be asked beyond δ is relevant:
M
α=-Iω
1ω
2
M
q=I(λ
1+λ
2)
Present vector to be estimated is:
[ξ]=[A
1,B
1,A
2,B
2,A
3,B
3,ω
1,ω
2,λ
1,λ
2]
T
Wherein A
1to B
3for the linear function of α, β, and ω
1to λ
2for the nonlinear function of α, β.
Set up evaluation function
J=∑[α(t)-α
i]
2+[β(t)-β
i]
2
Wherein α
i, β
ifor t=t
idata point.
By α (t), β (t) to often organizing variable ω
1, ω
2, λ
1, λ
2launch at discreet value ξ place, have
Wherein
extremely
for discreet value, ω
1to λ
2for the increment of discreet value.
By
the optimal estimation of ξ can be tried to achieve.Its component form as
have
Wherein residual error
Owing to being at precompensation parameter
place's value, therefore
deng being constant, the above formula left side first sport is zero, and has
If make [C
j]=[ω
1, ω
2, λ
1, λ
2]
tthen above formula is write as matrix expression and is:
[F
kj][C
j]=[Rl
k]
Wherein [F
kj] be square formation, row k j column element is
Such as
[Rl
k] be column vector, and have
Such as
By matrix expression, if [F
kj] without singular point, nonopiate again, then have
{ξ
j}=[F
kj]
-1{Rl
k}=[F
jk]{Rl
k}
By above formula, as long as [F
kj, R
lk] try to achieve, just can solution to make new advances
there is increment type again
Continue iteration, until residual sum of squares (RSS) is less than a certain required amount.
And [F
kj] and [
rlk] in every α, β to ω
1to λ
2partial derivative also can try to achieve:
Ask A now
1, B
1, A
2, B
2, A
3, B
3, the angle of attack and yaw angle can be written as:
Due to
In front formula, other partial derivative also can similarly be tried to achieve.So by
Above formula is to certain component (such as A
1) expression formula be
Consider
deng being constant at i point, so have:
Maybe can be rewritten as:
Above-mentioned equation has six, can solve A
1to B
3six unknown numbers, thus obtain every Dynamic stability parameter.