# US 2024/0053726 A1 · Method for controlling an actuation assembly

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- Number: US 2024/0053726 A1
- Document ID: US20240053726A1
- Status: Published application
- Kind: A1
- Application number: 18/270,798
- Filed: 2021-12-16
- Published: 2024-02-15
- Earliest claimed: 2021-01-04
- Assignees: Commissariat A L'energie Atomique Et Aux Energies Alternatives
- Applicants: Commissariat A L'energie Atomique Et Aux Energies Alternatives
- Inventors: Philippe GARREC
- Web page: https://patentgrep.com/patent/US20240053726A1

## CPC

- G05B 13/0215: {using trial and error method, including "peak-holding"}
- G05B 19/414: Structure of the control system, e.g. common controller or multiprocessor systems, interface to servo, programmable interface controller
- B66D 1/12: incorporating electric motors
- B66D 1/225: {variable ratio or reversing gearing (fixed ratio gearing B66D1/22)}
- B66D 1/485: {electrical}
- G05B 19/4103: Digital interpolation
- G05B 19/401: characterised by control arrangements for measuring, e.g. calibration and initialisation, measuring workpiece for machining purposes (G05B19/19 takes precedence)
- G05B 2219/41359: Gearbox
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)
- B66D: CAPSTANS; WINCHES; TACKLES, e.g. PULLEY BLOCKS; HOISTS (winding or unwinding ropes or cables for feeding or storage purposes B65H; rope or cable winding or unwinding mechanisms for lifts B66B)

## Abstract

Method for controlling an electric actuation assembly (1), the method comprising the following steps: applying a plurality of known first output forces and recording a plurality of first input intensities for a first movement direction of the output; establishing, by interpolation, a first characteristic function; applying a plurality of second known output torques and recording (2) a plurality of second input currents for a second movement direction of the output opposite to the first direction; establishing, by interpolation, a second characteristic function; establishing, on the basis of the first characteristic function, the second characteristic function, a magnetic constant of the motor (11) and a reduction ratio of a gearbox (12), and a control correction coefficient; controlling the actuation assembly (1) by applying the control correction coefficient.

## Claims

### Claim 1

Method for controlling an electric actuation assembly (1), comprising a current controller (2) connected to an actuator (10), the actuator (10) comprising a motor (11) coupled with a gearbox (12) having a known reduction ratio, the actuation assembly (1) being provided with an output (13), the method comprising the following steps:
applying a plurality of first known output forces on the output (13) of the actuation assembly and recording using the current controller (2), a plurality of associated first input intensities to be applied at the input of the actuation assembly (1) to obtain a balance of the actuation assembly (1) in a first direction of the output (13);
establishing, by interpolation, a first characteristic function of the actuation assembly (1) linking a controlled intensity at the input of the actuation assembly (1) and a force obtained at the output of the actuation assembly (1);
applying a plurality of second known output sources on the output (13) of the actuation assembly (1) and recording, using the current controller (2), a plurality of associated second input intensities to be applied at the input of the actuation assembly (1) to obtain a balance of the actuation assembly (1) in a second direction of the output (13) opposite to the first direction;
establishing, by interpolation, a second characteristic function of the actuation assembly (1) linking a controlled current at the input of the actuation assembly (1) and a force obtained at the output (13) of the actuation assembly (1);
establishing, on the basis of the first characteristic function of the actuation assembly (1), the second characteristic function of the actuation assembly (1) of a magnetic constant of the motor (11) and of the reduction ratio of the gearbox (12), a control correction coefficient intended to be applied by multiplication to a control input value;
controlling the actuation assembly (1) by applying the control correction coefficient.

### Claim 2 (depends on 1)

Method according to claim 1, wherein, the first characteristic function being a linear function which is written in the form
Csd(Ie)=a1*Ie+b1
Where:
a1 and b1 are constants determined by interpolation,
Csd is the force obtained at the output of the actuation assembly (1) for a movement of the output (13) in the first direction,
Ie is an intensity applied at the input of the actuation assembly (1),
the second characteristic function being a linear function which is written in the form:
Csi(Ie)=a2*Ie+b2
Where:
a2 and b2 are constants determined by interpolation,
Csi is the force obtained at the output of the actuation assembly (1) for a rotation of the output (13) in the second direction,
Ie is an intensity applied at the input of the actuation assembly (1),
the step of establishing a control correction coefficient comprises the calculation of the correction coefficient as follows:
λ
=
i
-
1
*
B
-
1
*
(
a
⁢
1
*
a
⁢
2
)
K
[
Math
⁢
1
]
Where:
B is a skewness coefficient which is calculated as follows:
B
=
R
⁢
d
R
⁢
i
[
Math
⁢
2
]
with
Rd: theoretical yield of the gearbox when the output charge of the gearbox is resistant;
Ri: theoretical yield of the gearbox when the output charge of the gearbox is motive
i is the reduction ratio
K is the electromagnetic constant
λ is the control input correction coefficient.

### Claim 3 (depends on 1)

Method according to claim 1, wherein, the first gearbox (12) comprising a strain wave gearing (30) defined by first construction parameters which comprise a first deformable outer ring shape, a first number of deformable outer ring teeth, a first toothing profile, a second number of inner ring teeth, the method comprises a preliminary calibration step comprising the following steps:
selecting a second gearbox (40) defined by second construction parameters identical to the first construction parameters;
establishing a third characteristic function of the second gearbox (40) linking a force applied at the input of the second gearbox (40) and a force obtained at the output of the second gearbox (40) for a movement of an output of the second gearbox (40) in a third direction;
establishing a fourth characteristic function of the second gearbox (40) linking a force applied at the input of the second gearbox (40) and a force obtained at the output of the second gearbox (40) for a movement of an output of the second gearbox (40) in a fourth direction opposite to the third direction;
determining a plurality of pairs of values such that:
x1-(1/i)*F3(x1)=F4(x2)-i*x2
wherein
x1 is a first abscissa
x2 is a second abscissa
i is the reduction ratio
F3 (x1) is the third characteristic function;
F4 (x2) is the fourth characteristic function;
interpolating a fifth function for determining the second abscissa according to the first abscissa in the form of a polynomial function of degree 2 being written:
x2=α*x12+β*x1+γ,
Where α, β and γ are constants determined by interpolation,
the first characteristic function being established in the form of a polynomial function of degree 2 which is written in the form
Csd(Ie)=a′1*Ie2+b′1*Ie+c′1
Where:
a′1, b′1 and c′1 are constants determined by interpolation;
Csd is the forced obtained at the output of the actuation unit (1) for a movement of the output of the second gearbox (40) in the third direction,
Ie is an intensity applied at the input of the actuator,
the second characteristic function being established in the form of a polynomial function of degree 2 which is written in the form
Csi(Ie)=a′2*Ie2+b′2*Ie+c′2
Where:
a′2, b′2 and c′2 are constants determined by interpolation;
Csi is the force obtained at the output of the actuation unit (1) for a movement of the output of the second gearbox (40) in the fourth direction,
Ie is a current applied at the input of the actuator,
the step of establishing a control correction coefficient comprises a step of adjusting the control coefficient so as to minimise the following sum of squares of deviations between the sixth and the seventh function:
F
⁢
6
⁢
(
X
)
=
a
′
⁢
2
*
X
2
+
b
′
⁢
2
*
X
+
c
′
⁢
2
[
Math
⁢
3
]
F
⁢
7
⁢
(
X
)
=
(
λ
*
i
-
α
-
1
*
λ
-
1
*
a
′
⁢
1
)
*
X
+
0.5
*
α
-
1
*
(
i
+
α
-
1
*
β
*
λ
-
2
*
a
′
⁢
1
-
λ
-
1
*
b
′
⁢
1
)
*
(
β
2
-
4
*
α
*
(
γ
-
λ
*
X
)
-
β
)
+
α
-
1
*
λ
-
2
*
a
′
⁢
1
*
γ
-
c
′
⁢
1
[
Math
⁢
4
]
Where: i is the reduction ratio
λ is the control input correction coefficient.

### Claim 4

Method according to any one of the preceding claims, wherein the actuator (10) is a rotary output actuator (13).

### Claim 5 (depends on 1, 2, 3)

Method according to any one of claims 1 to 3, wherein the actuator (10) is a linear output actuator (13).