GB2551247A - Active steering end-effector for composite processing and polymer processing heat source - Google Patents

Abstract

An end effector 16, suitable for a robotic arm 13 suitable for delivering a tape, comprising a tape laying mechanism and at least one actuator 28 suitable for moving the tape laying mechanism in one of the three spatial directions. The end-effector may include a camera (59, fig.3) for taking images of the tape and a controller for activating the at least one actuator according to the images. A second independent claim for a heat module suitable for polymer processing, comprising at least one plurality of semiconductor elements (113, fig.4), wherein the semiconductor element is provided suitable for radiating heat with a main lobe, wherein the semiconductor elements of the plurality are adapted for directing essentially the main lobes at one target area (120, fig.4). The invention aims to improve automated fibre placement (AFP) or automated tape laying (ATL) processes.

Description

ACTIVE STEERING END-EFFECTOR FOR COMPOSITE PROCESSING AND POLYMER PROCESSING HEAT SOURCE

This application relates to fiber placement, tape-laying, and composite processing and to a semiconductor-based heat-source for polymer processing. US 6544367 B1 shows a tape delivery end-effector apparatus, which includes, in an exemplary embodiment, a multiple-channel system for applying materials in tape form to a tooling mandrel . US 8256484 B2 show an end-effector constructing composite members, in which a compaction roller and redirect rollers translate synchronously along the compaction axis.

In the field of continuous fiber reinforcement, processes such as automated fiber placement (AFP) or automated tape laying (ATL) have become increasingly important for optimized structures, where the direction of reinforcement fibers can be varied to a greater degree than for instance with textile preforms .

However, due to the complexity of the process to follow exact fiber directions and the limitation of ultimate speed the machines can run, the output is typically lower than other composite manufacturing processes. In addition, the precision, affected by repeatability and position accuracy of the platform, is limited, which provides an upper limit to the degree of quality of the parts produced. Furthermore, both limitations are typically interdependent, such that increased production speed will decrease the precision.

More specifically, the aforementioned points are particularly limited with articulated arm robot platforms, which are otherwise highly desirable because of their flexibility and cost-effectiveness .

Another factor is that the programming of platforms carrying AFP/ATL end-effectors can become quite extensive for producing parts with even only limited complexity. Additional degrees of freedom provided by the application, in combination with sensors and control systems can provide self-adapting functionality. This can reduce the complexity of path planning and can also be exploited to optimize the simplified path for speed.

It is an objective of the application to provide an improved end-effector for composite processing

The application comprises of linear actuators, which are able to move the fiber placement or tape laying mechanism in either one of the three spatial directions relative to the platform's end-effector mounting point or a combination thereof.

For the purpose of this document, an x-axis movement shall be defined as principal direction of the placement mechanism along the reinforcement fibers. A y-axis movement shall be defined as direction perpendicular to the principal movement, in plane with the composite layup, therefore considered as "sideways". A z-axis movement shall be defined as direction perpendicular to the principal movement, out of plane of the composite layup, therefore considered as "vertical".

Lateral y-axis movement allows the reduction of gaps or overlaps due to inaccuracies introduced by the platform. Another benefit is the possibility to streamline the trajectory of the platform by handling of small deviations by the application.

The necessary control input is provided through parametric data, active sensors, or vision systems. A simpler variation thereof may also use passive methods.

The vertical z-axis movement of the application allows the platform to move the end-effector in a streamlined trajectory, avoiding the need to follow small curvatures, while maintaining the necessary consolidation pressure. In addition, the application allows the adjustment of the consolidation pressure according to pre-programmed features or dependent on process parameters. For instance, the consolidation force can be varied according to the speed in principal direction to optimize consolidation in varying speed.

The simplest variant of the application may be implemented as linear actuator with adjustable force, so it will follow contours and always exert the desired force in the z-axis direction. A more sophisticated variation thereof utilizes sensor data and parametric data as input.

The x-axis movement of the application allows the platform to move with continuous speed, while adjusting speed for short periods and within the limitations of the actuator. This can help to maintain constant speed relative to the substrate if the application is using the z-axis movement to equalize small curvatures. In addition, this claim is useful to allow integrated cutting mechanisms to meet precisely the part's specifications during high-speed layups.

In addition, the change in end-effector geometry provides some benefits with respect to potential collisions between end-effector and tooling.

Control input for the x-axis movements will utilize sensor data as well as parametric data.

The application provides an end-effector for a robotic arm for delivering a tape. The end-effector comprises a tape laying mechanism and one or more linear actuators for moving the tape laying mechanism in one of the three spatial directions with respective to relative to the end-effector.

Different implementations of the linear actuator are possible. The linear actuator can be adapted for moving the x-axis. The linear actuator can also be adapted for moving the y-axis. The linear actuator can also be adapted for moving the z-axis.

The end-effector often includes a camera for taking images of the tape and a controller for activating the at least one actuator according to the images.

The application also provides an improved heat source for polymer processing.

Polymer processing, such as fusion/welding, trimming/cutting, pre-heating, post-curing, reduction of internal stresses, thermo-forming, or surface treatment among others, often requires a heat source.

The application also provides an improved heat source for polymer processing.

The application provides a heat module for polymer processing. The polymer processing includes laying or placement of a fiber or polymer tape to produce devices, such as a pressure vessel.

The heat module includes at least one plurality of semiconductor elements. Each semiconductor element is provided for radiating heat with a main lobe or main beam. The radiation semiconductor elements of each plurality are adapted for directing essentially the main lobes at one target area.

The plurality of the semiconductor elements is often provided on a parabolic surface.

The target area can refer to a spot area.

The target area can also refer to a linear area.

The heat module can include a mirror arrangement for reflecting and redirecting the heat radiation of the semiconductor elements onto the target area.

The heat module can also include an optical arrangement for refracting and directing the heat radiation of the semiconductor elements onto the target area.

In other words, the application provides a plurality of heat radiating semiconductors, which are arranged in a way that their radiation is concentrated on an area to be heated. The semiconductors can be arranged in a parabolic shape for a spot target or in a linear array with parabolic cross-section for a line target. A structural fixture, where the semiconductors are placed on, may contain an energy supply, a cooling, or other required support functions.

The radiation of the semiconductors may be combined onto the target area, by either direct radiation, mirrors, optics, or any combination thereof.

The radiation, which is used for heating the target, would often comprise electromagnetic waves of a wavelength that highly correlates with the target absorption wavelengths. For practical systems and considering the availability of commercial semiconductors, this would mostly be in visual wavelengths, as well as in infrared wavelengths.

In contrast to other heating solutions, the application provides following advantages: fast response time, due to the speed in which semiconductors can be switched on and off, cost effectiveness due to the widespread availability of the semiconductors used, potentially high power density on the target area, focused heating with target area sizes of few square millimeter (mm2), and small size, which allows mounting of the system directly where needed.

In other words, these radiating semiconductors are different from heating systems, such as hot gas heating or incandescent lamps, which have slow response times and low efficiency.

These radiating semiconductors are also different from laser systems, which are costly, and usually require complicated setups with laser source, waveguide, and a head with optics. The small spot sizes of the laser systems are also not required for some polymer processing, such as fiber reinforced thermoplastics processing.

In one variation of the application, an alignment of individual radiating semiconductors, via means of an optical system or mirrors, can be adjusted to accommodate different uses. As an example, the array of radiating semiconductors could be reshaped from a spot focus to a wider area focus, when, as an example, the use changes from welding to reduction of internal stresses .

Fig. 1 illustrates a tape delivery apparatus,

Fig. 2 illustrates an electric z-axis actuator for an end-effector of the tape delivery apparatus of Fig. 1, Fig. 3 illustrates a tape placement device for the end- effector of the tape delivery apparatus of Fig. 1, Fig. 4 illustrates side cross-sectional view of a plurality of semiconductor element, and

Fig. 5 illustrates an array of the semiconductor elements of Fig. 4 being arranged in array.

In the following description, details are provided to de-scribe embodiments of the application. It shall be apparent to one skilled in the art, however, that the embodiments may be practiced without such details.

Some parts of the embodiment have similar parts. The similar parts may have the same names or similar part numbers with an alphabet symbol. The description of one similar part also applies by reference to another similar part, where appropriate, thereby reducing repetition of text without limiting the disclosure .

Fig. 1 shows a tape delivery apparatus 10. The apparatus 10 includes a robot arm 13 with an end-effector 16 for laying or placing a tape or a polymer layer for composite processing to produce a composite device, such as a polymer pressure vessel.

The end-effector 16 is attached to one end of the robot arm 13 while a ground platform 19 is attached to another end of the robot arm 13.

The end-effector 16 includes a roll 22 of tape, a tape compaction roller 25, a tape roller actuator 28, and a heating source 30. A part of the tape is placed at the tape compaction roller 25. The heating source 30 is placed near this part of the tape. The tape roller actuator 28 is connected to the tape compaction roller 25.

In use, the robot arm 13 acts to place the tape at one or more desired locations for adding the tape, often to a structure like a mandrel, to form a desired polymer product.

The tape is laid along an x-axis with respect to the end-effector 16, the x-axis being a principal direction of a tape placement device.

The tape roller actuator 28 moves the tape compaction roller 25 along a z-axis, which is perpendicular to the x-axis and out of the plane of the tape.

The heating source 30 then heats the part of the tape that has been laid for hardening and strengthening it.

Fig. 2 shows an electric z-axis actuator 35 for the end-effector of the tape delivery apparatus of Fig. 1. The actuator 35 uses a fluid, which can be air or liquid, for moving a compaction roller.

The actuator 35 includes a fluid pressure source 38, a fluid cylinder 42 with a piston 45, and a fluid pressure controller 48. The fluid pressure source 38 is fluidically connected to the fluid cylinder 42. The fluid pressure controller 48 is electrically connected to the fluid cylinder 42 and to the fluid pressure source 38.

In use, the fluid pressure source 38 exerts a pressure or force on a fluid according to an activation pressure signal from the pressure controller 48.

The fluid then transmits this pressure to the fluid cylinder 42 and to the piston 45. The piston 45 then exerts a force on a compaction roller that is connected to the piston 45 for moving the compaction roller in the z-axis.

The pressure controller 48 also receives a pressure measurement from a pressure sensor for measuring pressure in the fluid cylinder 42. The pressure controller 48 then generates an activation pressure signal according to the pressure measurement for sending to the fluid pressure source 38.

This actuator 35 allows for easy programming of the pressure controller 48 as it only provides rough positions.

Fig. 3 shows a tape placement device 50 for the end-effector of the tape delivery apparatus of Fig. 1.

The tape placement device 50 includes a tape placement element with a y-axis actuator 53 with an x-axis actuator 56 and an actuator control camera 59.

In use, the y-axis actuator 53 acts to move the tape placement element in the y-axis, which is described earlier, according to a y-axis activation signal from an actuator controller.

The x-axis actuator 56 acts to move the tape placement element in the x-axis, which is described earlier, according to an x-axis activation signal from the actuator controller.

The actuator control camera 59 take images of the tape placement and sends the images to the controller, wherein the controller generates a corresponding y-axis activation signal and a corresponding x-axis activation signal according to the images. The controller later sends the generated x-axis activation signal to the x-axis actuator 56 and sends the generated y-axis activation signal to the y-axis actuator 53.

The embodiments can also be described with the following lists of features or elements being organized into an item list. The respective combinations of features, which are disclosed in the item list, are regarded as independent subject matter, respectively, that can also be combined with other features of the application.

ITEMS 1. An actuator or a collection thereof mounted on automated fiber placement (AFP) or automated tape laying (ATL) end- effector 2. An actuator or a collection thereof, as per item 1, that can move main fiber laying mechanism in x-axis, y-axis, z-axis or any combination thereof 3. An actuator or a collection thereof, as per item 1, that responds to online input during operation 4. An actuator or a collection thereof that responds faster than the base platform it is mounted on, such as gantry or robotic system. 5. An actuator or a collection thereof that provides more precision than the base platform it is mounted on, such as gantry or robotic system. 6. An actuator or a collection thereof that automatically maintains the alignment of consecutive reinforcement fiber depositions . 7. A sensor system and control mechanism to provide input for item 6. 8. A mechanical system to provide the functionality described in item 6. 9. An actuator or a collection thereof, where the consolidation force can be varied according to the speed in principal direction to optimize consolidation of fiber material onto substrate. 10. An actuator or a collection thereof, in x-axis direction to reduce or increase speed relative to the trajectory of the base platform's end-effector attachment.

Fig. 4 shows a heat source 110 for polymer processing. The heat source 110 includes a plurality of semiconductor elements 113. The semiconductor elements 113 are positioned on a parabolic surface or line 116. In use, each energized semiconductor element 113 emits heat radiation with a main lobe that is directed at one target area 120 for heating the target area 120. In effect, the heat radiations of the multiple semiconductor elements 113 are essentially directed or are concentrated on the one target area 120.

Fig. 5 shows another heat source 200 for polymer processing. The heat source 200 includes a plurality of semiconductor elements 213 being positioned on a carrier structure 216. The carrier structure 216 includes an energy supply, which is not shown in the Figure, being electrically connected to the semiconductor elements 213. The semiconductor elements 213 being arranged in an array.

The carrier structure 216 is adapted such that, in use, the energized semiconductor elements 213 emit heat radiation with main lobes that are directed at a linear target area 220 for heating the target area 220. The heat radiations of the semiconductor elements 213 are directed or are focused on the one linear target area.

This focusing or concentrating of the heat radiation has an advantage of increasing heat radiation. Furthermore, the radiation is selectively directed at a desired area.

The embodiments can also be described with the following lists of features or elements being organized into an item list. The respective combinations of features, which are disclosed in the item list, are regarded as independent subject matter, respectively, that can also be combined with other features of the application. 1. Cost effective array of off-the-shelf semiconductors, 2. Parabolic arrangement for focused heating, 3. Electronic control circuit to allow fast response time and control of parameters, such as intensity, target area geometry, duration, movement patterns and others, for different use-cases, 4. Mirror arrangement to focus beams, and 5. Optical arrangement to focus beams.

Although the above description contains much specificity, this should not be construed as limiting the scope of the embodiments but merely providing illustration of the foreseeable embodiments. The above stated advantages of the embodiments should not be construed especially as limiting the scope of the embodiments but merely to explain possible achievements if the described embodiments are put into practice. Thus, the scope of the embodiments should be determined by the claims and their equivalents, rather than by the examples given.

REFERENCE LIST 10 tape delivery apparatus 13 robot arm 16 end-effector 19 ground platform 22 tape roll 25 tape compaction roller 28 tape roller actuator 30 heating source 35 actuator 38 fluid pressure source 42 fluid cylinder 45 piston 48 fluid pressure controller 50 tape placement device 53 y-axis actuator 56 x-axis actuator 59 actuator control camera 110 heat source 113 semiconductor element 116 parabolic surface or line 120 target area 200 heat source 213 semiconductor element 216 carrier structure 220 linear target area

Claims (11)

1. An end-effector for a robotic arm for delivering a tape, the end-effector comprises a tape laying mechanism, and at least one actuator for moving the tape laying mechanism in one of the three spatial directions with respective to relative to the end-effector.

2. The end-effector according to claim 1, wherein the least one actuator is adapted for moving the x-axis.

3. The end-effector according to claim 1 or 2, wherein the least one actuator is adapted for moving the y-axis.

4. The end-effector according to one of the above-mentioned claims, wherein the least one actuator is adapted for moving the z-axis.

5. The end-effector according to one of the above-mentioned claims further comprises a camera for taking images of the tape and a controller for activating the at least one actuator according to the images.

6. A heat module for polymer processing, the heat module comprising at least one plurality of semiconductor elements, wherein the semiconductor element is provided for radiating heat with a main lobe, and wherein the semiconductor elements of the plurality are adapted for directing essentially the main lobes at one target area.

7. The heat module according to claim 6, wherein the one plurality of the semiconductor elements is provided on a parabolic surface.

8. The heat module according to claim 6 or 7, wherein the target area comprises a spot area.

9. The heat module according to claim 6 or 7, wherein the target area comprises a linear area.

10. The heat module according to one of claims 6 to 9 further comprising a mirror arrangement for reflecting the heat radiation of the semiconductor elements onto the target area.

11. The heat module according to one of claims 6 to 9 further comprising an optical arrangement for refracting the heat radiation of the semiconductor elements onto the target area.