# US 2018/0023648 A1 · Systems and methods for clamping force estimation in electromechanical brake systems

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- Number: US 2018/0023648 A1
- Document ID: US20180023648A1
- Status: Published application
- Kind: A1
- Application number: 15/216,423
- Filed: 2016-07-21
- Published: 2018-01-25
- Earliest claimed: 2016-07-21
- Assignees: Goodrich Corporation
- Applicants: Goodrich Corporation
- Inventors: Sameep Singh
- Web page: https://patentgrep.com/patent/US20180023648A1

## CPC

- F16D 66/00: Arrangements for monitoring working conditions, e.g. wear, temperature
- B60T 13/741: {acting on an ultimate actuator}
- B64C 25/42: Arrangement or adaptation of brakes
- F16D 65/18: adapted for drawing members together {, e.g. for disc brakes}
- G01L 3/22: electrically or magnetically actuated
- G01L 5/22: for measuring the force applied to control members, e.g. control members of vehicles, triggers
- H02K 49/00: Dynamo-electric clutches; Dynamo-electric brakes
- F16D 2066/005: {Force, torque, stress or strain}
- F16D 2121/24: using motors
- F16D 2125/36: Helical cams, Ball-rotating ramps
- F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- B60T: VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL (electrodynamic brake systems for vehicle, in general B60L; brakes per se, i.e. devices where braking effect occurs, including ultimate brake actuators, F16D); ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B64C: AEROPLANES; HELICOPTERS
- G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G)
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})

## Abstract

An electromechanical brake system may include an electromechanical actuator with a servo motor. A current control is electronically coupled to the servo motor. A resolver is configured to detect an angular velocity and an angular position of the servo motor. A converter may be configured to convert the angular velocity into a linear velocity and the angular position into a linear position. An intelligent observer may also be configured to estimate a load force of the electromechanical actuator based on the linear position and the linear velocity.

## Claims

### Claim 1

An electromechanical brake system, comprising:
an electromechanical actuator comprising a servo motor,
a current control electronically coupled to the servo motor;
a resolver configured to detect an angular velocity and an angular position of the servo motor;
a converter configured to convert the angular velocity into a linear velocity and the angular position into a linear position; and
an intelligent observer configured to estimate a load force of the electromechanical actuator based on the linear position and the linear velocity.

### Claim 2 (depends on 1)

The electromechanical brake system of claim 1, wherein the intelligent observer is trained to estimate the load force based on a training torque load, a training linear position, and a training linear velocity, with the training linear position and the training linear velocity measured in response to an input current trajectory.

### Claim 3 (depends on 2)

The electromechanical brake system of claim 2, wherein the training torque load is a first product added to a second product, with the first product being a measured current multiplied by a torque constant and the second product being a derivative of a measured velocity multiplied by inertia.

### Claim 4 (depends on 2)

The electromechanical brake system of claim 2, wherein the intelligent observer is trained using a least square error method.

### Claim 5 (depends on 2)

The electromechanical brake system of claim 2, further comprising:
a ball screw mechanically coupled to the servo motor; and
a brake stack with the ball screw configured to apply a braking force to the brake stack.

### Claim 6 (depends on 2)

The electromechanical brake system of claim 2, wherein the intelligent observer is trained using expert observations.

### Claim 7 (depends on 1)

The electromechanical brake system of claim 1, wherein the intelligent observer is trained to estimate the load force based on a training measured current, a training linear position, and a training linear velocity each measured in response to an input current trajectory.

### Claim 8

A method of estimating a load force of an electromechanical brake actuator, comprising:
generating a set of rules to estimate the load force based on a plurality of linear velocities and a plurality of linear positions of the electromechanical brake actuator;
measuring a linear velocity and a linear position of the electromechanical brake actuator to yield a measured linear position and a measured linear velocity; and
applying the set of rules to the measured linear velocity and the measured linear position to estimate the load force.

### Claim 9 (depends on 8)

The method of claim 8, further comprising training an intelligent observer to estimate the load force based on a training torque load, a training linear position, and a training linear velocity, with the training linear position and the training linear velocity measured in response to an input current trajectory.

### Claim 10 (depends on 9)

The method of claim 9, further comprising computing the training torque load by:
multiplying a measured current by a torque constant to calculate a first product;
multiplying a derivative of a measured velocity multiplied by inertia to calculate a second product; and
adding the first product to the second product to calculate the training torque load.

### Claim 11 (depends on 8)

The method of claim 8, wherein the generating the set of rules further comprises using a least square error method.

### Claim 12 (depends on 8)

The method of claim 8, further comprising applying a braking force to a brake stack based on the load force.

### Claim 13 (depends on 8)

The method of claim 8, wherein the generating the set of rules further comprises using expert observations.

### Claim 14

An aircraft brake, comprising:
an electromechanical actuator comprising a servo motor, a gear train coupled to the servo motor, and a ball screw coupled to the gear train, wherein the ball screw is configured to translate linearly in response to a rotation of the servo motor;
a current control electronically coupled to the servo motor, wherein a current sensor is configured to measure a feedback current through the servo motor with the feedback current used to generate an input for the current control;
a resolver configured to detect an angular velocity and an angular position of the servo motor; and
an intelligent observer configured to estimate a load force of the electromechanical actuator based on the angular position and the angular velocity.

### Claim 15 (depends on 14)

The aircraft brake of claim 14, wherein the intelligent observer is configured to estimate the load force based on a linear velocity converted from the angular velocity based on a gear ratio.

### Claim 16 (depends on 14)

The aircraft brake of claim 14, wherein the intelligent observer is trained to estimate the load force based on a training torque load, a training linear position, and a training linear velocity, with the training linear position and the training linear velocity measured in response to an input current trajectory.

### Claim 17 (depends on 16)

The aircraft brake of claim 16, wherein the training torque load is a first product added to a second product, with the first product being a measured current multiplied by a torque constant and the second product being a derivative of a measured velocity multiplied by inertia.

### Claim 18 (depends on 15)

The aircraft brake of claim 15, wherein the intelligent observer is trained using a least square error method.

### Claim 19 (depends on 15)

The aircraft brake of claim 15, further comprising a brake stack with the ball screw configured to apply a braking force to the brake stack.

### Claim 20 (depends on 14)

The aircraft brake of claim 14, wherein the intelligent observer is trained to estimate the load force based on a training measured current, a training linear position, and a training linear velocity each measured in response to an input current trajectory.