Embodiment
For example the present invention is done more detailed description below:
For the virtual guide P on the given expectation track path Ω in the step 1 do at the function that the coordinate of fixed coordinate system can be expressed as a certain scalar parameter s ∈ R
In order to guarantee to be required x by the slickness of track path
d(s), y
d(s), z
d(s) second-order partial differential coefficient exists.
The speed u of defining virtual guide point P
pDirection is the angle ψ along the tangential direction of curved path and fixed coordinate system transverse axis
dFor
ψ
d=arctan(y′
d/x′
d) (2)
Velocity vector u
pAngle theta with the fixed coordinate system Z-axis
dBe defined as
Where
Wizard and the virtual point P along a curved path, respectively, the rotational angular velocity can be expressed as
The initial position of given then AUV under fixed coordinate system is η
n=[x, y, z]
T, the initial bow of AUV is respectively ψ and θ to angle and trim angle, AUV longitudinal velocity u, transverse velocity v and vertical velocity w, yaw angle speed r and pitch velocity q.
So far accomplished the initialization setting in the step 1.
The detailed process of calculating the three-dimensional path tracking error in the step 2 is following:
Fig. 1 follows the tracks of synoptic diagram for owing to drive the AUV three-dimensional path, and { position vector of I} is defined as the virtual guide point P on its desired track path Ω at fixed coordinate system
{ position vector under the I} is defined as η to AUV at fixed coordinate system
n=[x, y, z]
T, ε=[x
e, y
e, z
e]
TFor { the tracking error vector can be expressed as so obtain tracking error under the B} with respect to the AUV carrier coordinate system
Wherein
is that { B} is to fixed coordinate system { rotation matrix of I}, the commentaries on classics order of
representing matrix
for the AUV carrier coordinate system.
Differentiate gets to formula (6)
Because
Wherein
Following formula substitution formula (8) is got
Consider
Wherein
ν
b=[u, v, w]
TBe the velocity vector under the carrier coordinate system;
ν
F=[u
p, 0,0]
T{ velocity vector of RP under the F}, substitution formula (10) becomes for the expectation path coordinate system
Launch
Wherein
Put in order
ψ wherein
e=ψ-ψ
d, θ
e=θ-θ
d
So far accomplished and calculated the tracking error between the virtual guide P on AUV and the expected path, below design process provide the tracking error ε how basis calculates, calculation control signal
AUV three-dimensional path tracking error variable for providing in the step 2 calculates the kinematics Virtual Controller respectively according to following formula
(1) the expectation translational speed computing formula of virtual guide point P on the expected path:
Wherein parameter satisfies u
d>0,
regulatory factor 0<λ<1, c>0, γ>0,
Be the tracking error distance under the AUV carrier coordinate system.
(2) AUV longitudinal velocity kinematics control law of equal value is:
a
u=u
pcosψ
ecosθ
e-k
1x
e (16)
(3) AUV pitch velocity kinematics control law of equal value is:
α
q=q
d+(k
4z
eu
p-k
5sinθ
e) (17)
(4) AUV yaw angle speeds control law of equal value is:
α
r=cosθ[r
d-(k
2cosθ
ey
eu
p?+k
3sinψ
e)] (18)
K wherein
1>0, k
2>0, k
3>0, k
4>0, k
5>0 is the design of Controller parameter.
The detailed process of design AUV three-dimensional path pursuit movement Virtual Controller is following in the step 3:
Because there is deviation in kinematics controller of equal value with true control input quantity, therefore defines deviation variables and do
For given Track In Track error equation (14), structure Liapunov energy function
To formula (20) differentiate, formula (16)~(18) and formula (19) substitution are got
Resolving the detailed process of controlling input instruction through the AUV mathematical model in the step 4 is:
According to AUV actual measurement hydrodynamic force coefficient, ignore the influence of rolling motion to model, it is following to obtain AUV five degree of freedom mathematical model
Wherein
g
1=(W-B)cosθ,g
2=(z
gW-z
bB)sinθ
(23)
d
1=X
u+X
u|u||u|,d
2=Y
v+Y
v|v||v|
d
3=Z
w+Z
w|w||w|,d
4=M
q+M
q|q||q|
d
5=N
r+N
r|r||r|
Wherein, state variable u, v, w, q and r represent carrier coordinate system { longitudinal velocity of AUV, transverse velocity, vertical velocity, pitch velocity and yaw angle speed under the B} respectively; M and m
()Represent AUV quality and the additional mass that produces by the fluid effect respectively, I
yBe the moment of inertia of AUV around the y axle, I
zBe the moment of inertia of AUV around the z axle, X
(), Y
(), Z
(), M
()And N
()Be the viscous fluid hydrodynamic force coefficient; z
gAnd z
bBe respectively under the carrier coordinate coordinate position of center of gravity and centre of buoyancy on the Z-axis, W and B represent gravity and the buoyancy that AUV receives, d respectively
()Be nonlinear damping hydrodynamic force item, control input F
u, τ
qAnd τ
rRepresent AUV propeller thrust, trim control moment respectively and change the bow control moment.
Here convolution (23) design AUV three-dimensional path is followed the tracks of Dynamics Controller and is done
Wherein
Here variable u
e=u-α
u, r
e=r-α
r, q
e=q-α
qBe defined as the actual value of kinematics controller output and the deviation of expectation value, gain coefficient k
u>0, k
q>0, k
r>0; Prove that through Lyapunov stability theory AUV three-dimensional path tracking Control rule formula (24) can guarantee the asymptotic stability of tracking error closed-loop system.
The detailed process of design AUV three-dimensional path tracking dynamics controller of equal value does in the step 4
Convolution (20) structure Liapunov energy function does
To the differentiate of following formula both sides, formula (21) substitution is got
Put in order
Formula (22) and formula (24) substitution are got, and formula (28) becomes
(29)
Because AUV lateral movement velocity v and catenary motion speed w are the less dividing value that has in the formula (29), and can know existence by the AUV kinetic characteristic | v|<u
Max, | w|<u
Max, u
MaxBe the AUV longitudinal velocity upper bound, so and if only if (x
e, y
e, z
e, ψ
e, θ
e, u
e, r
e, q
e)=0 o'clock
Can be got by the LaSalle invariance principle, closed loop tracking error system is asymptotic stable, through adjustment control gain coefficient k
1, k
2, k
3, k
4, k
5And k
u, k
q, k
rThe dynamic property of assurance system.
The detailed process of step 5 is:
Calculate current AUV position η
n=(x, y is z) with the turning point WP that demarcates
k=(x
k, y
k, z
k) between distance
If switch radius R less than the flight path of setting, then the tracing task of the current specified path of expression completion stops navigation or switches next desired track, otherwise continues step 2.
Simulating, verifying and analysis
Illustrate below, be the validity that the three-dimensional Track In Track controller of AUV of design is invented in checking, carry out emulation experiment to the three-dimensional curve path of planning, and compare analysis with the traditional PID control simulation result:
Said according to step 1 in the summary of the invention, at first provide the parametric description that three-dimensional curve is followed the tracks of in expectation
Parameter A=20 wherein, ω=0.02 π
" virtual guide " initial position message on the three-dimensional curve is followed the tracks of in given expectation
The initial velocity variable parameter u of " virtual guide " on the three-dimensional curve is followed the tracks of in given expectation
d=1 (m/s), gain parameter λ=0.5, c=1, γ=1, controller parameter k
1=50, k
2=10, k
3=100, k
4=20, k
5=100; k
u=1, k
r=5, k
q=10; Adopt MATLAB numerical simulation platform, resolve the input of AUV three-dimensional path tracking Control according to step 2~4 and obtain final simulation curve.
Simulation analysis
Fig. 4~Figure 10 provides AUV three-dimensional curve path trace control simulation result.Fig. 4 is an AUV three-dimensional spiral dive path trace track; Fig. 5 and Fig. 6 are respectively AUV three-dimensional path pursuit path and get drop shadow curve at surface level and vertical plane; Therefrom can find out because each degree of freedom of three-dimensional motion of AUV has coupling; Controller parameter is difficult for regulating when adopting the traditional PID controller controller, and the control effect is relatively poor, can't realize the accurate tracking to three-dimensional path; And the gamma controller that the present invention is based on accurate model design can fine realization tracking Control, has improved the path trace precision.Fig. 7 is a tracking error curve in the AUV three-dimensional path tracking Control; Compare with the traditional PID controller controller; Can find out that the three-dimensional path controller that this paper designs has improved the precision of path trace, shorten the redundant voyage of AUV, have more stable control ability and guarantee that AUV follows the tracks of and converge to expected path faster; Make tracking error finally converge to zero, shown the tracking accuracy and the response speed of controller.Fig. 8 and Fig. 9 are respectively the change curve that each state variable in the AUV three-dimensional path tracking Control process comprises linear velocity and attitude angle; Can find out that AUV is less than longitudinal velocity along transverse velocity and vertical velocity in the helix dive process; And, when design of Controller, can ignore for dividing value is arranged.Figure 10 is AUV three-dimensional path tracking Control input response.