Adaptive feedback control of an optronic sight
An optronic sight for a motorized vehicle such as an aerial or marine vehicle propelled by a propeller, or a tracked land vehicle. The optronic sight can include an aiming module, means for moving the aiming module about the first and second axes, and means for continuously measuring angular data. The optronic sight can further include a feedback control loop having means for continuously measuring the acceleration of the aiming module in three orthogonal directions of the space, means for detecting at least one fundamental frequency of the vibratory disturbances, and an adaptive corrector configured to continuously receive as input said fundamental frequency, a discrepancy between an angular setpoint value and said angular data, output a movement setpoint value to the moving means.
1 . An optronic sight for a motorized vehicle such as an aerial or marine vehicle propelled by a propeller or a tracked land vehicle, the optronic sight comprising:
an aiming module configured to be moved about a first axis and a second axis not parallel to the first axis,
means for moving the aiming module about the first and second axes,
means for continuously measuring an angular data of the aiming module about the first and second axes;
a feedback control loop, comprising:
means for continuously measuring the acceleration of the aiming module according to three orthogonal directions of a space; and
means for detecting at least one fundamental frequency of the vibratory disturbances generated by the operation of the motorized vehicle, the at least one fundamental frequency being obtained based on the output data of the acceleration measuring means; and
an adaptive corrector configured to:
continuously receive as input:
said fundamental frequency; and
a discrepancy between an angular setpoint value and said angular data; and
output a movement setpoint value to the moving means.
2 . The optronic sight of claim 1 , wherein the means for continuously measuring the angular data include a gyroscope configured to obtain an angular position or a gyrometer configured to obtain an angular speed.
3 . The optronic sight of claim 1 , wherein the means for measuring the acceleration comprise an accelerometer.
4 . The optronic sight of claim 1 , wherein the fundamental frequency is obtained by Fast Fourier Transform followed by a calculation of a maximum in the frequency band obtained after carrying out the Fast Fourier Transform or by phase-locked loop.
5 . The optronic sight of claim 1 , wherein the adaptive corrector comprises a Linear Variant Parameter corrector.
6 . The optronic sight of claim 5 , wherein the adaptive corrector follows a state representation according to the following formula:
{
x
k
+
1
=
A
(
f
^
vk
)
x
k
+
B
(
f
^
vk
)
ε
k
u
k
=
C
(
f
^
vk
)
x
k
+
D
(
f
^
vk
)
ε
k
f
min
≤
f
^
vk
≤
f
max
where xk is the state variable of the corrector, ε_k is the feedback control error at the input of the adaptive corrector, uk is the digital motor command calculated by the adaptive corrector (output of the corrector), fmin and fmax are two frequencies limiting the fundamental frequency in real-time {circumflex over (f)}_vk of the disturbing vibrations γ_vib.
7 . The optronic sight of claim 5 , wherein the Linear Variant Parameter (LPV) corrector comprises the following affine state matrices:
A
(
f
^
vk
)
=
A
0
+
f
^
vk
A
1
B
(
f
^
vk
)
=
B
0
+
f
^
vk
B
1
C
(
f
^
vk
)
=
C
0
+
f
^
vk
C
1
D
(
f
^
vk
)
=
D
0
+
f
^
vk
D
1
where A 0 , B 0 , C 0 , D 0 , A 1 , B 1 , C 1 , D 1 designate matrix gains which are the parameters saved in the memory of the corrector.
8 . The optronic sight of claim 1 , wherein the first axis and the second axis are perpendicular to each other.
9 . A motorized vehicle, such as an aerial or marine vehicle propelled by a propeller or a tracked land vehicle, comprising an optronic sight according to claim 1 .