# US 10,870,501 B2 · Flight vehicle attitude control system design method and device

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- Number: US 10,870,501 B2
- Document ID: US10870501B2
- Status: Granted
- Kind: B2
- Application number: 16/200,952
- Filed: 2018-11-27
- Published: 2019-06-13
- Granted: 2020-12-22
- Earliest claimed: 2017-12-08
- Assignees: Korea Aerospace Research Institute
- Applicants: Korea Aerospace Research Institute
- Inventors: Yong-Kyu Park; Byung-Chan Sun
- Web page: https://patentgrep.com/patent/US10870501B2

## CPC

- B64F 5/00: Designing, manufacturing, assembling, cleaning, maintaining or repairing aircraft, not otherwise provided for; Handling, transporting, testing or inspecting aircraft components, not otherwise provided for
- B64F 5/60: Testing or inspecting aircraft components or systems
- G01M 9/08: Aerodynamic models
- G06F 30/20: Design optimisation, verification or simulation (optimisation, verification or simulation of circuit designs G06F30/30)
- B64F: GROUND OR AIRCRAFT-CARRIER-DECK INSTALLATIONS SPECIALLY ADAPTED FOR USE IN CONNECTION WITH AIRCRAFT; DESIGNING, MANUFACTURING, ASSEMBLING, CLEANING, MAINTAINING OR REPAIRING AIRCRAFT, NOT OTHERWISE PROVIDED FOR; HANDLING, TRANSPORTING, TESTING OR INSPECTING AIRCRAFT COMPONENTS, NOT OTHERWISE PROVIDED FOR
- G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

A flight vehicle attitude control system design device includes: a gain calculator calculating a proportional gain and a derivative gain from a system natural frequency and a system damping coefficient; a margin calculator calculating a gain margin and a phase margin from the proportional gain and the derivative gain; a grid generator generating a gain-phase margin grid from a relationship between the proportional gain and the derivative gain and a relationship between the gain margin and the phase margin; and a display unit outputting the gain-phase margin grid on a control gain design region having a gain margin as one of a horizontal coordinate axis and a vertical coordinate axis and a phase margin as the other one of the horizontal coordinate axis and the vertical coordinate axis.

## Claims

### Claim 1

A flight vehicle attitude control system design device comprising:
input device receiving an input of a system natural frequency and a system damping coefficient;
a gain calculator, using the system natural frequency and the system damping coefficient received by the input device, calculating a proportional gain and a derivative gain;
a margin calculator, using the calculated proportional gain and the calculated derivative gain, calculating a gain margin and a phase margin;
a grid generator generating a gain-phase margin grid from a relationship between the calculated proportional gain and the calculated derivative gain and a relationship between the calculated gain margin and the calculated phase margin; and
a display unit outputting the generated gain-phase margin grid on a control gain design region having a gain margin as one of a horizontal coordinate axis and a vertical coordinate axis and a phase margin as the other one of the horizontal coordinate axis and the vertical coordinate axis.

### Claim 2 (depends on 1)

The flight vehicle attitude control system design device of claim 1, wherein the display unit outputs a lower limit of the gain margin and a lower limit of the phase margin on the control gain design region.

### Claim 3 (depends on 2)

The flight vehicle attitude control system design device of claim 2, wherein the display unit outputs an upper limit of a bending mode vibration transmission rate.

### Claim 4 (depends on 3)

The flight vehicle attitude control system design device of claim 3, wherein the display unit outputs an upper limit and a lower limit of the system natural frequency and an upper limit and a lower limit of the system damping coefficient.

### Claim 5 (depends on 4)

The flight vehicle attitude control system design device of claim 4, wherein the input device receives an input of a control gain point corresponding to a point on the control gain design region, and
the flight vehicle attitude control system design device further comprises a control gain selector selects a coordinate value of the control gain point as a control gain for flight vehicle attitude control.

### Claim 6 (depends on 5)

The flight vehicle attitude control system design device of claim 5, wherein the control gain selector determines whether the control gain point satisfies the lower limit of the gain margin and the lower limit of the phase margin.

### Claim 7 (depends on 3)

The flight vehicle attitude control system design device of claim 3, wherein, when a pitch/yaw control thrust is Tc, the proportional gain is KP, the derivative gain is KD, an ith-order bending mode slope at a rate sensor location is σP,i and σR,i, an ith-order bending mode shape at a thrust vector control (TVC) gimbal position is ϕtvc,i, an ith-order bending mode damping coefficient is ζbd,i, an ith-order bending mode natural frequency is ωbd,i, and an ith-order bending mode generalized mass is Mbd,i, an upper limit KDT,i of an ith-order bending mode vibration transmission rate represented as a function thereof is defined through
K
BT
,
i
=

T
c
⁢
ϕ
tvc
,
i
M
bd
,
i
⁢
(
K
P
⁢
σ
P
,
i
+
j
⁢
⁢
ω
bd
,
i
⁢
K
D
⁢
σ
R
,
i
)
2
⁢
ζ
bd
,
i
⁢
ω
bd
,
i
2

.
[
Equation
⁢
⁢
5
]

### Claim 8 (depends on 1)

The flight vehicle attitude control system design device of claim 1, wherein the display unit outputs the gain-phase margin grid obliquely with respect to a coordinate axis of the control gain design region.

### Claim 9 (depends on 1)

The flight vehicle attitude control system design device of claim 1, wherein the gain-phase margin grid includes two axes intersecting each other,
one of the two axes has the same derivative gain value, and
the other one thereof has the same proportional gain value.

### Claim 10 (depends on 1)

The flight vehicle attitude control system design device of claim 1, wherein, when the system natural frequency is ωn, the system damping coefficient is ζn, a dimensional aerodynamic force moment coefficient is Ma, and a dimensional thrust moment coefficient is Ms, the proportional gain KP and the derivative gain KD represented as a function thereof are obtained through
K
P
=
ω
n
2
+
M
a
M
δ
⁢
⁢
and
[
Equation
⁢
⁢
1
]
K
D
=
2
⁢
ζ
n
⁢
ω
n
M
δ
,
[
Equation
⁢
⁢
2
]
the gain margin and the phase margin are obtained from a relationship of open-loop transfer functions
G
⁡
(
j
⁢
⁢
ω
)
=
N
⁡
(
j
⁢
⁢
ω
)
D
⁡
(
j
⁢
⁢
ω
)
=
N
⁡
(
j
⁢
⁢
ω
)
⁢
D
⋆
⁡
(
j
⁢
⁢
ω
)

D
⁡
(
j
⁢
⁢
ω
)

2
⁢
⁢
and
[
Equation
⁢
⁢
3
]
GM
=
-
1
G
⁡
(
j
⁢
⁢
ω
pc
)
,
PM
=
180
⁢
⁢
deg
+
<
G
⁡
(
ω
gc
)
[
Equation
⁢
⁢
4
]
of an attitude control system in which dynamic characteristics of the flight vehicle are represented as a function of a frequency ω, and
D(jω) and N(jω) are represented as a function of the proportional gain KP and the derivative gain KD.

### Claim 11

A flight vehicle attitude control system design method performed by a flight vehicle attitude control system design device including at least one processor, an input device, and a display unit, the flight vehicle attitude control system design method comprising:
receiving, by the input device of the flight vehicle attitude control system design device, an nth system natural frequency and an nth system damping coefficient representing dynamic characteristics of a flight vehicle with respect to an nth time;
using the nth system natural frequency and the nth system damping coefficient received by the input device, calculating, by a gain calculator of the flight vehicle attitude control system design device, an nth proportional gain and an nth derivative gain;
using the calculated nth proportional gain and the calculated nth derivative gain, calculating, by a margin calculator, an nt gain margin and an nth phase margin;
generating, by a grid generator, an nth gain-phase margin grid from a relationship between the calculated nth proportional gain and the calculated nth derivative gain and a relationship between the calculated nth gain margin and the calculated nth phase margin; and
outputting, by the processor, for display on a display unit, the generated nth gain-phase margin grid on a control gain design region having a gain margin as one of a horizontal coordinate axis and a vertical coordinate axis and a phase margin as the other one of the horizontal coordinate axis and the vertical coordinate axis.

### Claim 12 (depends on 11)

The flight vehicle attitude control system design method of claim 11, further comprising:
receiving, by the input device, an input of an nth control gain point corresponding to a point on the control gain design region; and
acquiring, by the processor, an nth control gain for attitude control of the flight vehicle from a coordinate value of the nth control gain point.

### Claim 13 (depends on 11)

The flight vehicle attitude control system design method of claim 11, further comprising an operation of outputting an (n+1)th gain-phase margin grid on the control gain design region by repeating the calculating, generating and outputting operations with respect to an (n+1)th time.

### Claim 14 (depends on 11)

The flight vehicle attitude control system design method of claim 11, wherein the dynamic characteristics of the flight vehicle vary as the time changes.

### Claim 15 (depends on 11)

The flight vehicle attitude control system design method of claim 11, further comprising an operation of outputting at least one of a lower limit of the nth gain margin, a lower limit of the nth phase margin, an upper limit of an nth bending mode vibration transmission rate, an upper limit and a lower limit of the nth system natural frequency, and an upper limit and a lower limit of the nth system damping coefficient on the control gain design region.

### Claim 16 (depends on 15)

The flight vehicle attitude control system design method of claim 15, further comprising an operation of determining whether the nth control gain point satisfies the at least one limit.