WO2014033249A1

WO2014033249A1 - Positioning system and method for positioning an article

Info

Publication number: WO2014033249A1
Application number: PCT/EP2013/067973
Authority: WO
Inventors: Markus Behn
Original assignee: Aktiebolaget Skf
Priority date: 2012-08-30
Filing date: 2013-08-30
Publication date: 2014-03-06
Also published as: DE102012215358A1; CN104620061A; EP2890939A1; US20150233607A1

Abstract

A positioning system for an article (2) to be transferred in a controlled manner from a starting position along a path of movement comprising an azimuthal rotation into an end position has a pretensioning device, which is connected to the article (2) and is designed to exert on the article (2) a force acting permanently in the direction of the path of movement, wherein the force has a component acting in an azimuthal direction. A braking device (22) is designed to fix the article (2) in a predetermined position along the path of movement.

Description

Positioning System and Method for Positioning an Object Embodiments of the present invention are concerned with a positioning system and a method for positioning an article.

Positioning systems, by means of which an object can be guided in a controlled manner from a starting position to an end position, are known in a large number of embodiments. For example, in a variety of solar applications panels with photovoltaic cells or with mirrors / lenses for concentrating light onto a common focal point (such as in CPV, Heliostats, Stirling Dish, Solar Trough or Linear Fresnel systems), the following all under The term solar panels can be summarized as defined with respect to the sun, whereby highly accurate systems are needed to follow the daily course of the sun. In particular, in systems in which the incident light energy is to be concentrated on a point or a certain surface, the positioning, ie the orientation of these objects positioned by means of the positioning systems must be carried out with the greatest possible accuracy. Absolutely, therefore, a game in the mechanics of the system (backlash) should be avoided.

Conventional positioning systems using linear actuators or worm gears, have such a game systemic. For example, in some systems, worm drives act on gears to effect rotation of the panels. A game results, for example, in that during the drive, the gears or worms with a flank are in contact, while after the drive or after switching off the propulsion system change of flanks, for example by a dynamic, acting on the panel load can be done. there In the case of solar applications, for example, an inaccuracy of 0.105 ° to 0.135 ° can lead to a significant decline in efficiency and inefficiency of the entire system. Furthermore, in such conventional systems, the energy required to operate the positioning system is relatively high, since the drive motors must be energized during the positioning, in the case of solar systems during the entire time of solar radiation, resulting in significant power losses.

Although the above-mentioned tracking systems or positioning systems for solar applications predominantly change an orientation of the objects moved with the positioning system, equivalent considerations also apply to positioning systems in which the object changes its position while moving from a starting position a movement path in a controlled way into an end position we transferred. In these systems, the object thus changes its position along a 3-dimensional locus in space, which is controlled by the positioning system. In this case, the identical problems arise regardless of whether the positioning system has one or more degrees of freedom, so whether the system can control one, two or three axes or one, two or three location coordinates.

In view of the hitherto known state of the art, there is a need to provide positioning systems which can be operated more energy-efficiently and flexibly than hitherto.

According to some embodiments of the present invention, this is accomplished by having a positioning system for a controlled from an initial position along an azimuthal rotation movement path in an end position to be transferred object having a biasing device connected to the object, which on the object one permanently in the direction of the movement path acting force having an acting in an azimuthal direction component. In order to be able to fix the object at a predetermined position or in a predetermined orientation along the movement path, the positioning system additionally has a braking device, which is designed to fix the object at the predetermined position, ie, to be permanent counteract acting force such that the object is fixed in the predetermined position at which the braking device is activated. That is, the object is not actively accelerated or moved by means of a motor along the movement path, but rather acted upon by a permanently acting in the direction of the movement path force, wherein the force at those positions or orientations to which the object brought or in which Object is to be fixed by means of the braking device is compensated, which sets the object in its current orientation or position. This results in a considerable energy saving in positioning compared with conventional systems, since electric motors which may be used in the system do not have to be permanently charged in order to position the object appropriately.

In addition, fixing the position of the object along the path of travel increases the achievable positioning accuracy, since a backlash inherent in the motor drives can not affect the positioning accuracy.

According to some embodiments, the force acting in the direction of the movement path is effected by means of a spring which can be biased against the path of travel, so that the restoring force of the elastic spring can be used to exert the permanently acting force on the object. Of course, the spring force can be used for a movement in one, two or three axes or space coordinates. This can be determined by suitable choice of the geometric boundary conditions. Generally speaking, in some embodiments of the invention, the force is effected by means of an element which can store potential or mechanical energy, that is, can change its state such that in an initial state the element has a greater potential energy than in a final state.

According to some other embodiments, the permanent force is generated by means of a weight which is brought into a starting position against the start of the positioning or movement of the object along the movement path. The weight is coupled or connected to the object such that the weight force acting on the weight on the object causes the force acting in the direction of the movement path. This procedure can lead to considerable energy savings, since the mechanical device, which causes the force permanently acting on the object, only at the beginning of a movement or a shutdown of a nes movement path must be biased to the starting position. That is, a combustion or electric motor used to bring the pretensioner to the home position need only be energized or energized for a short time.

Such a return device, which transfers the object against the permanently acting force from the end position to the starting position and at the same time brings the pretensioning device into the starting position, can be, for example, an electric motor, an internal combustion engine, a mechanism driven by alternative energies such as hydropower, solar power, wind power or the like or engine.

According to some embodiments, a positioning system having one or two axes is used to track a solar panel over the course of the day of the sun. This can significantly improve the overall energy balance or the overall efficiency of the system through the achievable energy savings in positioning.

According to some embodiments, the positioning system of the solar panel is uniaxial. Ie. a solar panel rotatably mounted about a rotation axis extending in a horizontal direction is tracked by means of the positioning system to the position of the sun. In this case, according to one embodiment, a frame for the solar panel to be mounted on the frame is designed such that its center of gravity, in particular if the solar panel has already been installed on the frame, lies outside the axis of rotation of the solar panel, so that the force of gravity permanently acting in the direction of the movement path of the geometry of the solar panel itself is generated. The functionality of a pretensioning device can therefore be made available by the geometry of the frame or of the solar panel itself.

In some embodiments, the magnitude of the force may be varied by the solar panel or its frame additionally having a cantilever extending perpendicularly to the axis, to which a weight is attached at a predetermined distance from the axis of rotation, thereby increasing the height of the permanent action Force can be adapted to the circumstances. In some embodiments, the magnitude of the force may also be adjusted to the size of the panel used by the position the additional weight on the boom, in particular the distance from the axis of rotation is varied.

In some embodiments, the position of the solar panel is tracked not only in one axis, so for example with respect to the elevation (height above the horizon), but also in a second axis, for example, the azimuth. In these embodiments, the permanent force acting in the direction of movement therefore also has an azimuthal direction acting component. This component or the force can be generated for example by means of a spring, which is located between two arms, which are arranged on the one hand on a foundation and on the other to a movable part of the positioning system. In alternative embodiments, a torsion spring between the two relatively rotating components can be used. Both in one- as well as biaxial positioning systems for solar panels or other objects whose orientation is to be changed in two axes, the braking device is designed to fix the position of the object with respect to each of the axes of rotation, ie with respect to the axial or horizontal axis of rotation , Ie. the rotation of the object to be positioned is suppressed with respect to one or both axes and the object is thus fixed with respect to these axes. By the

Fixing with respect to the axes by means of an additional braking device Due to the separation of the drive and the fixation of the object to be positioned, the mechanical play inherent in the drive can be avoided, so that the positioning accuracy increases.

Some preferred embodiments of the present invention will be explained in more detail below with reference to the attached figures. Show it:

1 shows a positioning system for a solar panel with a movable axis. and

Fig. 2 shows a positioning system for a solar panel with a second movable axis. 1 shows an exemplary embodiment of the present invention in which a solar panel 2, for example a photovoltaic module or also a mirror, can be aligned by means of a positioning system in such a way that it follows the position of the sun during the course of the day.

The solar panel 2 is mounted on a frame 4 which is rotatably supported by means of a running in the horizontal direction 6 axis of rotation 8 with respect to a stationary and in a vertical direction 10 to a foundation 12 extending mast 14.

Also attached to a boom 16 extending away from the axis of rotation 8 is a weight 18 which extends from the initial position of the weight 18 shown in FIG. 1 to an end position where the weight 18 is in the lowest possible position determined by the geometry is located, is movable. Due to the weight, a force acting on the solar panel 2 or the frame 4 is permanently exerted between these two positions for the purpose of positioning the solar panel 2, that is to say acting in the direction of the movement path of the solar panel 2. As a movement path in the sense to be understood here is thus in the embodiment shown in Fig. 1 that change of orientation or the elevation angle 20 between the surface normal of the solar panel 2 and the horizontal direction 6 to understand the solar panel 2 at a complete tilting the axis 8 learns. Generally speaking, the movement path should be understood to mean any change in a variable which describes an orientation or a location of an object and which is to be varied or varied during a tracking or controlled movement of an object.

Already at the beginning of the movement, that is to say in the starting position of the solar panel 2 shown in FIG. 1, the weight force of the weight 18 acts in the direction of the movement path, so that without a braking device the solar panel 2 would perform an unstoppable movement from the starting position to the end position. To prevent this, the embodiment in Fig. 1, a braking device 22 in the form of a brake, which makes it possible to prevent the rotation of the panel 2 and the frame 4 with respect to the axis 8, ie the position of the frame 4 or of the panel 2 with respect to the horizontal axis of rotation 8 can fix. As a retractor 24, the embodiment of FIG. 1, an electric motor 26 which can exert on a deflected cable to a remote from the weight 18 end of the boom 16 acting counter to the permanently acting force return force to the biasing means, the present from the Weight 18 on the boom 16 is to be able to bring back into the starting position shown in FIG.

Although in the exemplary embodiment shown in FIG. 1 an additional weight 18 is provided for generating the permanently acting force, it goes without saying that in other embodiments the biasing device which applies the force permanently acting in the direction of the movement path to the Solar panel 2 exercises, can also be implemented in any other way. For example, this may be formed by the geometry of the frame 4 and the solar panel 2 or the attachment of the solar panel 2 on the axis 8 itself. If, for example, the geometry of the geometry is such that the center of gravity of the panel lies outside the axis 8, then the required force, which acts permanently in the direction of the movement path, is exerted solely by the geometric arrangement. Of course, the permanently acting force can also be exerted or effected in any other way, for example by means of one or more springs, for example torsion springs on the axle 8 or by means of differently shaped weights, for example by reservoirs filled with a liquid or the like.

By the braking device 22 on the axis 8 ensures that the positioning accuracy is extremely large, since the drive and the brake are designed separately from each other and thus games contained in the drive not affect the positioning accuracy negative. In other words, the solar panel 2 or the frame 4 itself becomes part of the positioning system. In other words, in the exemplary embodiment shown in FIG. 1, the solar panel 2 or the solar mirror is equipped with a weight 18. Before the sun rises, the weight 18 is lifted by means of the electric motor 26 in the starting position shown in Fig. 1. Thus, the system is overnight "relaxed." The axis adjusting the elevation 20 is thereby biased, ie, a force permanently acts on it in the direction of the movement path of the solar panel through the weight 18. During the course of the day, the weight 18 is continuously controlled by the braking device 22, tilted down, whereby the elevation angle 20 of the solar panel changes, so that this always optima with respect to the current position of the sun le alignment has. This can be determined for example by means of the location coordinates of the positioning system, which in turn can be determined for example via a GPS system, astronomical calendars, Hall sensors that indicate the current position of the axis, and a built reference point, so that the tracking at any time optimally can succeed. Modern energy storage and intelligent software control ensure that emergency positioning (panel horizontal) can be started at any time. Control recognizes whether weight needs to be raised or merely lowered. In the evening, the weight 18 has arrived in its final position at the lower end of the mast 14. If during the day storms or other, the device impairing weather conditions occur, the solar panel 2 can of course be moved before the end of the day artificially in an emergency position in which the panel is in the horizontal. Before sunrise, the weight 18 is pulled back into the initial position shown in Fig. 1, to which the retractor 24 is used. According to some embodiments, for example, the power generated by the solar panel itself can be used for this, without compromising the efficiency of the solar panel during the daytime, in that permanent power would have to be applied to positioning motors. For this reason, a self-locking brake is used in some embodiments as a braking device 22, so a brake, in which only to release the

Brake control current is required so that most of the time no power loss occurs on the arrangement. In other words, some embodiments are based on the fact that the center of gravity of the frame or the common center of gravity of the solar panel and the frame is deliberately outside the axis, so that the moment caused thereby can be used for driving.

FIG. 2 shows a further exemplary embodiment of the invention which is based on FIG. 1, in which tracking of the solar panel 2 (tracking) also takes place in an azimuthal direction, ie. H. the motion path also has a component that corresponds to an azimuthal rotation, ie a change in an azimuth angle 28.

In order to make this possible, in the embodiment shown in FIG. 2, the mast 14 is rotatably mounted with respect to the foundation 12, wherein the biasing device additionally has a first arm 30 which is connected to the mast 14 and thus also with respect to the azimuth. len direction with the frame 4 and the panel 2 is rigidly connected. The positioning system further comprises a second arm 32 which is stationary, that is, for example, rigidly connected to the foundation 12. By means of a spiral spring 34, a force acting permanently in the azimuthal direction 28 is generated between the first arm 30 and the second arm 32, ie a force which acts permanently along the azimuthal component of the movement path of the solar panel. In order to enable the controlled movement, the arrangement of Fig. 2 further comprises a further braking device acting between the mast 14 and the foundation 12, so that by means of the further braking device, the position of the frame with respect to the vertical axis of rotation can be fixed. It goes without saying that also for the second and controllably movable axis shown in Fig. 2 any other device can be used to achieve the force acting continuously in the direction of the movement path. This may, for example, be any other form of spring, for example a torsion spring, between the mast 14 and the foundation 12.

Although in the preceding embodiment, for a uniaxial tracking only the tracking of the elevation has been shown, according to other uniaxial embodiments, only the azimuth can be tracked by means of a biasing device.

Although in the preceding two embodiments, the inventive concept has been illustrated predominantly on the basis of a tracking system for a solar panel 2, it goes without saying that in other embodiments, other positioning systems can make use of the teaching of the invention. Including, of course, those in which not only the orientation of an object is changed, but also its geometric location, in which therefore moves the controlled by the positioning system to be moved object along a predetermined trajectory in space. LIST OF REFERENCE NUMBERS

2 solar panels

4 frames

6 horizontal direction

8 axis of rotation

10 vertical direction

12 foundation

14 mast

16 outriggers

18 weight

20 elevation angles

22 braking device

24 return device

26 electric motor

28 azimuth angle

30 first arm

32 second arm

34 spiral spring

Claims

P a n t a n s p r e c h e

A Positioning System and Method of Positioning an Object 1. A positioning system for a movement path comprising an azimuthal rotation from a home position to an end position to be transferred (2), comprising:

A biasing means connected to the object (2) and configured to exert on the object (2) a force permanently acting in the direction of the travel path, the force having a component acting in an azimuthal direction; and

A brake device (22) configured to fix the article (2) in a predetermined position along the travel path.

A positioning system according to claim 1, wherein the biasing direction comprises an element capable of storing a potential energy such that the force is generated by means of the stored potential energy.

3. A positioning system according to claim 2, wherein the biasing means comprises a counter to the movement path tensionable spring (34) and / or a counter to gravity movable weight (18) which is coupled to the object (2) such that one on the Weight (18) acting force of gravity causes the force acting in the direction of the movement path.

A positioning system according to any one of the preceding claims, further comprising return means (24) adapted to transfer the article (2) against the permanently acting force from the end position to the initial position.

5. A positioning system according to one of the preceding claims, wherein the object is a solar panel (2) which is rotatably mounted about a in a horizontal direction (6) extending axis of rotation (8).

6. A positioning system according to claim 5, further comprising a frame (4) for the solar panel (2), the center of gravity of the mounted solar panel (2) outside the axis of rotation (8).

7. A positioning system according to claim 6, wherein the frame has a perpendicular to the axis of rotation (8) extending arm (16) to which a weight (18) is mounted at a predetermined distance from the axis of rotation (8).

8. A positioning system according to any one of claims 5 to 7, wherein the braking means (22) is adapted to fix the position of the frame (4) or the solar panel (2) with respect to the axis of rotation (8).

9. A positioning system according to any one of the preceding claims, wherein the frame (4) is further rotatably mounted with respect to a vertical axis of rotation perpendicular to the horizontal direction (6), wherein the biasing means is a first vertically extending from the vertical axis and with respect to the frame fixed arm (30) and a second stationary arm (32), wherein the first (30) and the second arm (32) via a spring (34) are interconnected.

10. A positioning system according to claim 9, wherein the braking means (22) is further adapted to fix the position of the frame (4) or the solar panel (2) with respect to the vertical axis of rotation.

11. A method of controllably transferring an object from a home position to an end position over a plurality of intermediate positions along an azimuthal rotation travel path comprising: exerting a permanent force on the article in the direction of the travel path, the force being in an azimuthal direction having acting component; and fixing the article at an intermediate position along the movement path by means of a braking device.