US 10,946,593 B2Granted

Heater system for fiber placement machine

AssigneeThe Boeing Company

InventorsBrice A. Johnson, Samuel F. Pedigo, Sayata Ghose, John Z. Lin

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Abstract

Closed-loop systems and methods for controlling the temperature at the compaction point as an automated fiber placement (AFP) machine is placing material over complex surface features at varying speeds. The closed-loop system starts with multiple infrared temperature sensors directed at the layup surface in front of the compaction roller and also at the new layup surface behind the compaction roller. These sensors supply direct temperature readings to a control computer, which also receives speed data and a listing of active tows from the AFP machine and is also programmed with the number of plies in the current layup. In accordance with one embodiment, the heater control system uses a proportional-integral-derivative loop to control the temperature at the compaction point (e.g., at the interface of the compaction roller and a newly laid tow) and regulate the heater power to achieve the desired temperature.

Claims21

Dependent claims

An automated fiber placement machine comprising:

a head comprising a compaction roller;
a tool disposed to form a compaction zone between the tool and the compaction roller;
a heater mounted forward of the compaction roller and configured to convert electrical power into heat for heating a substrate on the tool;
a heater power controller configured to convert heater power control signals to an output voltage which is used to power the heater;
a first temperature sensor directed at a first measurement spot on the substrate located either forward of the compaction roller and aft of the heater or aft of the compaction roller, wherein the first temperature sensor, when operative, outputs first temperature data when the compaction roller is in contact with the substrate;
a non-transitory tangible computer-readable storage medium storing computer code representing a thermal model comprising thermal model data representing a correlation curve that relates compaction point temperature of the substrate to temperature sensor measurements, wherein the thermal model is configured to estimate an estimated compaction point temperature of the substrate under the compaction roller based at least in part on the thermal model data representing the correlation curve, the first temperature data output by the first temperature sensor and a speed at which the head is moving;
and
a computing system configured to perform operations comprising:
using the thermal model to estimate the estimated compaction point temperature of the substrate under the compaction roller based at least on the first temperature data output by the first temperature sensor and the speed at which the head is moving;
calculating a current difference between the estimated compaction point temperature and a target compaction point temperature;
generating heater power control signals for changing the electrical power supplied to the heater in a manner that will reduce a subsequent difference between the estimated and target compaction point temperatures;
and
outputting the heater power control signals to the heater power controller.

10 more elements

A method for controlling a heater during placement of tows of fiber-reinforced plastic material on a tool by a head of a fiber placement machine, comprising:

a non-transitory tangible computer-readable storage medium storing computer code representing a thermal model comprising thermal model data representing a correlation curve that relates compaction point temperature of the substrate to temperature sensor measurements, wherein the thermal model is configured to estimate an estimated compaction point temperature of the substrate under the compaction roller based at least in part on the thermal model data representing the correlation curve, the first temperature data output by the first temperature sensor and a speed at which the head is moving;
and
(a) creating a thermal model comprising thermal model data representing a correlation curve that relates compaction point temperature of the substrate to temperature sensor measurements, wherein the thermal model is configured to estimate an estimated compaction point temperature of a substrate at a compaction point between a tool and a compaction roller based to at least in part on the thermal model data representing the correlation curve, a first temperature of a substrate at a first measurement spot and a speed at which the head is moving, wherein the first measurement spot is on the substrate located either forward of the compaction roller and aft of a heater or aft of the compaction roller when the compaction roller is in contact with the substrate;
(b) compacting tows of fiber-reinforced plastic material on the substrate by rolling the compaction roller on a surface of the substrate with the tows therebetween;
(c) heating the substrate in an area upstream of the first measurement spot during compaction using the heater;
(d) acquiring a first temperature measurement from the first measurement spot;
(e) using the thermal model to estimate a current estimated compaction point temperature that is a function of at least the first temperature measurement;
(f) calculating a difference between the current estimated compaction point temperature and a target compaction point temperature;
(g) issuing control signals that represent a command to supply an amount of electrical power to the heater, which amount of electrical power is calculated to reduce the difference between a subsequent estimated compaction point temperature and the target compaction point temperature;
and
(h) supplying the amount of electrical power to the heater,
wherein at least steps (e) through (g) are performed by a computing system.

9 more elements

A method for controlling a heater during placement of tows of fiber-reinforced plastic material by a fiber placement machine, comprising:

(a) compacting tows of fiber-reinforced plastic material on a substrate supported by a tool by rolling a compaction roller on a surface of the substrate with the tows therebetween at a speed;
(b) heating the substrate in an area upstream of the compaction roller using a heater;
(c) acquiring a first temperature measurement from a first measurement spot on a portion of the substrate located aft of the heater and forward of the compaction roller;
(d) acquiring a second temperature measurement from a second measurement spot on a portion of the substrate located aft of the compaction roller;
(e) determining whether the first and second temperature measurements are valid or not;
(f) executing an open-loop control algorithm when the first and second temperature measurements are not valid;
(g) executing a closed-loop control algorithm when the first and second temperature measurements are valid, wherein step (g) comprises:
estimating a current estimated compaction point temperature that is a function of the speed at which the compaction roller is moving and at least one of the first and second temperature measurements;
calculating a difference between the current estimated compaction point temperature and a target compaction point temperature;
and
issuing control signals that represent a command to supply an amount of electrical power to the heater, which amount of electrical power is calculated to reduce the difference between a subsequent estimated compaction point temperature and the target compaction point temperature;
and
(h) supplying the amount of electrical power to the heater,
wherein at least steps (e) through (g) are performed by a computing system.

11 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/696,041Filed 26 Nov 2019 · continuation
Priority: 29 Aug 2017
Published: US 2020/0094494 A126 Mar 2020
Granted: 16 Mar 2021
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

B29C 70/384
Automated fiber placement [AFP]: fiber placement heads, e.g. component parts, details or accessories
B29C 35/0288
Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould: controlling heating or curing of polymers during moulding,…
B29C 35/0805
By wave energy or particle radiation: using electromagnetic radiation
B29C 2035/0822
Using electromagnetic radiation: using IR radiation

Family

Application15/689,703Parent of this continuation · filed 29 Aug 2017
US 2020/0094494 A1Pre-grant publication · published 26 Mar 2020
US 10,525,638 B2Parent of this continuation
US 2019/0061282 A1Published application
US 10,946,593 B2This patent

From the US filing history. Foreign family members aren’t listed.