# US 10,981,640 B2 · Method and system for verification of tow end placement

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- Number: US 10,981,640 B2
- Document ID: US10981640B2
- Status: Granted
- Kind: B2
- Application number: 16/036,337
- Filed: 2018-07-16
- Published: 2020-01-16
- Granted: 2021-04-20
- Earliest claimed: 2018-07-16
- Assignees: The Boeing Company
- Applicants: The Boeing Company
- Inventors: Thomas J. Hagman
- Web page: https://patentgrep.com/patent/US10981640B2

## CPC

- B29C 70/382: {Automated fiber placement [AFP]}
- B29C 70/386: {Automated tape laying [ATL]}
- B64C 1/00: Fuselages; Constructional features common to fuselages, wings, stabilising surfaces or the like
- G05B 5/01: electric
- G05B 2219/35113: Generation of compound, composite surface
- G05B 2219/37617: Tolerance of form, shape or position
- Y02T 50/40: Weight reduction
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B64C: AEROPLANES; HELICOPTERS
- 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)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A method and apparatus for managing tow end placement. A time at which movement of a tow is initiated or stopped during a layup process is detected. A latency between the time and a command time corresponding to a command to begin movement or stop movement of the tow is determined. A determination is made as to whether the latency is within a desired range. A timing offset used by a control system that controls tow layup is adjusted in response to a determination that the latency is not within the desired range.

## Claims

### Claim 1

A method for managing tow end placement, the method comprising:
detecting a start time at which movement of a tow is initiated for a layup process;
determining a start latency between the start time and a start command time at which a start command to begin movement of the tow is received;
determining whether the start latency is within a desired range;
adjusting a start timing offset used by a control system that controls tow layup in response to a determination that the start latency is not within the desired range; and
controlling the tow layup using the start timing offset that has been adjusted.

### Claim 2 (depends on 1)

The method of claim 1, wherein adjusting the start timing offset comprises:
measuring a position of a tow end of a different tow on a tuning surface.

### Claim 3 (depends on 2)

The method of claim 2, wherein adjusting the start timing offset further comprises:
computing an error between the position of the tow end of the different tow and an expected position for the tow end of the different tow; and
determining whether the error is within selected tolerances.

### Claim 4 (depends on 3)

The method of claim 3, wherein adjusting the start timing offset further comprises:
adjusting the start timing offset based on the error.

### Claim 5 (depends on 1)

The method of claim 1, further comprising:
normalizing the start latency based on a first layup speed used during the layup process to generate a normalized latency, wherein the start command is an actuation command for a tow feed mechanism.

### Claim 6 (depends on 5)

The method of claim 5, wherein adjusting the start timing offset comprises:
adjusting the start timing offset based on the normalized latency and a second layup speed to be used in a future layup process.

### Claim 7 (depends on 1)

The method of claim 1, wherein detecting the start time comprises:
detecting the start time using a sensor that detects when the movement of the tow begins.

### Claim 8 (depends on 1)

The method of claim 1, further comprising:
detecting a stop time at which movement of the tow is stopped during the layup process; and
determining a stop latency between the stop time and a stop command time at which a stop command to stop movement of the tow is received, wherein the stop command is an actuation command for a tow feed mechanism.

### Claim 9 (depends on 8)

The method of claim 8, further comprising:
determining whether the stop latency is within a desired range; and
adjusting a stop timing offset used by the control system when the stop latency is not within the desired range.

### Claim 10 (depends on 1)

The method of claim 1, wherein adjusting the start timing offset comprises:
adjusting the start timing offset to control a numerically-controlled system that performs the layup process.

### Claim 11 (depends on 1)

The method of claim 1, further comprising:
providing a composite object for an aircraft, the composite object being comprised of tows laid up via the layup process.

### Claim 12

A method for managing tow end placement, the method comprising:
detecting a stop time at which movement of a tow is halted for a layup process;
determining a stop latency between the stop time and a stop command time at which a stop command to halt movement of the tow is received;
determining whether the stop latency is within a desired range;
adjusting a stop timing offset used by a control system that controls tow layup in response to a determination that the stop latency is not within the desired range; and
controlling the tow layup using the stop timing offset that has been adjusted.

### Claim 13 (depends on 12)

The method of claim 12, wherein adjusting the stop timing offset comprises:
adjusting the stop timing offset to control a numerically-controlled system that performs the layup process.

### Claim 14 (depends on 12)

The method of claim 12, further comprising:
providing a composite object for an aircraft, the composite object being comprised of tows laid up via the layup process.

### Claim 15

An apparatus for verifying tow end placement, the apparatus comprising:
a sensor system that detects a start time at which movement of a tow is initiated for a layup process; and
a control system that determines a start latency between the start time and a start command time at which a start command to begin movement of the tow is received; determines whether the start latency is within a desired range; adjusts a start timing offset used by the control system in response to a determination that the start latency is not within the desired range; and controls the tow layup using the stop timing offset that has been adjusted.

### Claim 16 (depends on 15)

The apparatus of claim 15, wherein the start command is an actuation command for a tow feed mechanism.

### Claim 17 (depends on 16)

The apparatus of claim 16, wherein the actuation command is for a pinch roller.

### Claim 18 (depends on 15)

The apparatus of claim 15, further comprising:
a tuning surface, wherein the control system identifies a position of an end of a different tow laid up on the tuning surface; computes an error between the position of the end of the tow and an expected position for the end of the tow; and determines whether the error is within selected tolerances.

### Claim 19 (depends on 18)

The apparatus of claim 18, wherein the control system adjusts the start timing offset based on the error.

### Claim 20 (depends on 18)

The apparatus of claim 18, wherein the selected tolerances are a deviation of less than 0.1 inches of the expected position.

### Claim 21 (depends on 15)

The apparatus of claim 15, wherein the control system normalizes the start latency based on a first layup speed used during the layup process to generate a normalized latency.

### Claim 22 (depends on 21)

The apparatus of claim 21, wherein the control system adjusts the start timing offset based on the normalized latency and a second layup speed to be used in a future layup process.

### Claim 23 (depends on 15)

The apparatus of claim 15, wherein the sensor system includes a sensor device for each tow feed mechanism of an automated fiber placement (AFP) system.

### Claim 24 (depends on 15)

The apparatus of claim 15, wherein the sensor system detects a stop time at which movement of the tow is stopped during the layup process.

### Claim 25 (depends on 24)

The apparatus of claim 24, wherein the control system determines a stop latency between the stop time and a stop command time at which a stop command to stop movement of the tow is received, wherein the stop command is an actuation command for a tow feed mechanism.

### Claim 26 (depends on 25)

The apparatus of claim 25, wherein the control system further determines whether the stop latency is within a desired range; and adjusts a stop timing offset used by the control system when the stop latency is not within the desired range.

### Claim 27 (depends on 26)

The apparatus of claim 26, further comprising:
a numerically-controlled automated fiber placement system that is controlled by the control system based on adjustments to the start timing offset and the stop timing offset.

### Claim 28 (depends on 15)

A method of fabricating a portion of an aircraft using the apparatus of claim 15.