DE102018216699A1 - Locking device and LIDAR measuring system with locking device - Google Patents

Abstract

The invention relates to a locking device (10, 30, 40) for locking a body (11) in one position. The locking device (10, 30, 40) comprises a device (12) for generating a magnetic or electric field in at least a predetermined area of the locking device (10, 30, 40) and a deformable material (13) arranged within the predetermined area is formed, in response to the magnetic or electric field, which acts on the deformable material (13), to change its geometric extension in order to determine the body (11) in position.

Description

The present invention relates to a locking device for locking a body in position. Furthermore, the invention relates to a LIDAR measuring system with at least one pivotably mounted element and a locking device according to the invention.

To hold or position a rotatably or pivotably mounted element in a predetermined, fixed position, devices can be used that use a form fit or a force fit. In this case, a design with a form fit has the disadvantage that a holding function can only be realized in defined, discrete positions due to a grid resulting from the form fit. For example, a structure with an actuator and a brake shoe requires a plurality of individual parts, which may require a large installation space, and is therefore not practical, particularly in the case of compactly designed adjustment units or positioning systems.

The object of the invention is to provide a locking device with a reduced size, which enables improved locking of a body to be locked in a predetermined position.

The object is achieved in accordance with the independent patent claims. Further aspects and developments of the invention, which can bring about additional advantages, are described in the dependent claims, the following description and in connection with the figures.

Accordingly, a locking device for locking a body in position is provided. The locking device according to the invention comprises a device for generating a magnetic or electric field in at least one predetermined area of the locking device. Furthermore, the locking device comprises a deformable material which is arranged within the predetermined range and which is designed to change its geometric extent in response to the magnetic or electrical field which acts on the deformable material in order to determine the body in position.

According to the invention, the locking device thus makes it possible to fix a movable body in a predetermined position. The movable body can be a rotatable mechanical shaft, a linearly displaceable body, such as an element of a telescope, or any other body that can, for example, perform rotational and / or translatory movements. For example, the body can be moved by a positioning device into a predetermined position without the locking action of the locking device, in which position it can subsequently be held or fixed by the locking device.

To fix or fix the body, the fixing device has a deformable material, which changes its geometry depending on the magnetic or electrical field acting on it. For example, the deformable material or generally a deformable element, which is at least partially formed from the deformable material, has a first length for a first field strength acting on the deformable material and a second length of the first length for a second field strength acting on the deformable material different length. For example, a change in length is accompanied by an opposing change in width of the deformable material, so that when the geometric extent changes, a volume of the material, e.g. B. remains constant. For the width compensation of the deformable material, a free space can be provided next to the deformable material in the locking device. Alternatively, a change in volume of the deformable material can also occur with some deformable materials.

For example, the deformable material comprises magnetically and / or electrically active material which reacts to a magnetic or electrical field that is present in each case. Examples of such materials are magnetorheological material, for example a magnetorheological elastomer, magnetostrictive material, piezoelectric material or electrostrictive material.

In order to control or influence the geometric expansion of the deformable material, depending on the type of deformable material used, the locking device has at least one device for generating a magnetic and / or electrical field. The device is arranged in such a way that a generated field acts at least partially on the deformable material of the locking device.

In a first operating state, the device for generating the magnetic and / or electrical field can be deactivated, so that no field is generated by it. For example, the deformable material can thereby be expanded in a field-free state in an expansion direction in the direction of an installation position of the body to be locked, so that in the installed state of the locking device it is fixed on the body due to the expansion of the deformable material. In other words, the deformable material presses against the body, so that one Frictional force arises, which holds the body in the respective position.

In a second operating state, in which the device for generating the magnetic and / or electrical field is activated, a field acts on the deformable material, so that it contracts along the direction of expansion. This allows the contact between the deformable material and the body to be released, so that the body is released for setting a position.

In a controlled or active operating state of the device for generating the magnetic and / or electrical field, the body to be ascertained can thus be moved and the body can be fixed by deactivating the device. This can result in the advantage that no energy is required for the locking device in the fixed state. Alternatively, the effect can also be reversed, so that the locking device holds the body in the activated state and releases it in the non-activated state.

The locking device can advantageously allow a body to be fixed in systems with limited installation space, for example in distance measuring systems. The deformable material for fixing the body can be provided with a small volume or space requirement. In particular, only a small or reduced number of individual parts may be required. According to the invention, a locking effect results from a deformation of the deformable material of the locking device. For example, it is possible to implement a holding function with a very high resolution within a compact adjustment device with high installation space requirements.

According to one embodiment of the locking device, the locking device is designed to fix bodies which can move in rotation. For example, a mechanical shaft can be accommodated in a locking device with a circular cross-section, which is released or locked depending on the operating state of the locking device. The locking device is thus designed, depending on the operating mode of the locking device, to prevent or enable a rotational movement of the body to be locked or of the mechanical shaft.

For example, magnetorheological elastomer can be provided as the deformable material. A magnetorheological elastomer consists for example of elastomer and magnetically active particles dispersed therein, e.g. Iron particles. A change in a magnetic field acting on the magnetorheological elastomer causes a change in the length of the magnetorheological elastomer. The magnetorheological elastomer expands or contracts in one direction depending on an acting magnetic field. In this case, the device for generating a magnetic field can be designed as an electrical coil. The magnetorheological elastomer can be formed, for example, by a deformable element which consists exclusively of magnetorheological elastomer. Alternatively, the deformable element can additionally or exclusively comprise magnetostrictive material, which also expands or contracts depending on a magnetic field.

For example, the locking device has a base body, for example a holder for the deformable material. The deformable material can be received in a recess of the base body of the locking device. For example, an extension of the recess in an expansion direction of the deformable element is smaller than an extension of the deformable material in an expanded state of the deformable material. The base body can be arranged contactlessly next to the body to be ascertained, so that the deformable material is accommodated in the recess in a contracted state without fixing the body, and emerges from the recess in an expanded state in order to exert a braking force on the body.

The deformable material can be inserted into the recess or at least attached to the base body at an interface of the recess provided by the base body. Inserting the deformable material can make it easy to replace the deformable material. For example, in an assembled state of the locking device on the body to be fixed, it is ensured that the inserted deformable material does not fall out of the recess. Alternatively, the deformable material e.g. be glued to the interface and / or be clamped between two interfaces of the recess at least in one end region of the recess. The advantage here can be that the deformable material can remain arranged in the recess even when the locking device is not arranged on a body to be locked.

According to a development of the locking device, a locking element is arranged on a side surface of the deformable material, which comprises a material different from the deformable material. The locking element can, for example, transmit a higher frictional force to the body than the deformable material itself. For example, the locking element can be formed from steel, metal, and / or plastic. One facing the body The surface of the locking element can be rough, for example, in order to increase a coefficient of friction and thus to improve a locking effect.

According to a development of the locking device, it has a plurality of deformable elements each comprising deformable material. For example, two, three or more deformable elements are arranged in the locking device in such a way that they can act symmetrically on the body to be fixed. For example, the locking device is designed to lock a mechanical shaft and the deformable elements are arranged uniformly around a cylindrical recess in the locking device, which is designed to receive the shaft. For example, two different deformable materials can be provided. By providing several deformable elements e.g. a locking force can be increased and / or a locking force can be transmitted more evenly to the body to be fixed and / or redundancy to increase the reliability of the locking device is made possible.

According to one embodiment, the locking device comprises a hollow cylindrical base body, which comprises a magnetic material at least in some areas. A mechanical shaft, for example, can be accommodated within the hollow cylindrical base body. Furthermore, the locking device according to the embodiment comprises at least one coil winding for generating the magnetic field, which acts on an element comprising the deformable material, the coil winding being wound around the base body in a partial area of the base body. However, the coil winding does not necessarily have to be wound around the base body, but can also be attached in a different way. The base body can be partially formed by an iron yoke. In the iron yoke, the magnetic field can be guided to the respective deformable material. For example, the base body has a non-magnetically conductive material within a circumferential region in which the deformable material is arranged, so that a magnetic field guided in the base body can act on the deformable element, for example a magnetorheological elastomer, and is not conducted past it. Alternatively, the magnetic material in this area can only be made thin enough or so thin that it becomes magnetically saturated.

In one embodiment of the locking device, the deformable material comprises piezoelectric material which, when the electric field is generated in the deformable material, causes an expansion change in the deformable material by applying an electrical voltage. For example, deformable elements which are accommodated in recesses in a base body of the locking device can comprise the piezoelectric material.

Alternatively, the deformable material is formed by a hollow cylindrical element and an inner diameter of the deformable material depends on a tension applied to the deformable material. For example, a piezo ring can be provided, the inside diameter of which increases when a voltage is applied to its side faces. A mechanical shaft that can be accommodated in the piezo ring can thereby be released. When the piezo ring is in a voltage-free state, the inside diameter of the piezo ring can decrease, so that a mechanical shaft arranged therein can be fixed by the piezo ring.

According to one embodiment, the deformable material is arranged at least in a peripheral region of a hollow cylindrical base body, so that an internal diameter of the base body changes due to a change in length of the deformable material in the peripheral direction of the base body. For example, the base body can be designed analogously to a clamp, with an extended state of the deformable material opening the clamp and a contracted state of the deformable material closing the clamp. A mechanical contact of the base body with the movable body can therefore achieve a locking effect. The base body can, for example, comprise two deformable elements or, in addition to a deformable element or material, can comprise a hinge or a mechanical joint that enables the clamp provided by the base body to be opened and closed.

Different embodiments of the locking device can be used in combination. This can e.g. increase a locking force of the locking device and / or a functional reliability of the locking device.

One aspect of the invention relates to a LIDAR measuring system with at least one pivotable element which is pivotably mounted on a mechanical shaft. The LIDAR measuring system further comprises a locking device according to the invention, which is arranged on the shaft, the locking device being fastened to a bearing bracket or housing part of the LIDAR measuring system in which the shaft is received. The shaft is fixed in a first state of expansion of the deformable material by means of the locking device and in a second state of expansion of the deformable material for pivoting the released pivotable element. For example, the pivoting element can be used to set a detection range of the LIDAR measuring system. A pivoting direction of the pivotable element set by means of an actuator can be fixed by means of the locking device, so that a set detection range can be maintained.

The basic structure of the LIDAR measuring system is based on the state of the art ( WO 2017/081294 A1 ) educated. The LIDAR measuring system preferably comprises a LIDAR transmitter unit and a LIDAR receiver unit. For example, the LIDAR transmitting unit and the LIDAR receiving unit are arranged on a common pivotable element that can be fixed or fixed in one position or angular position by means of the locking device of the LIDAR measuring system.

The LIDAR receiver unit and / or the LIDAR transmitter unit are advantageously designed in a focal plane array configuration. The elements of the respective unit are essentially arranged in one plane, advantageously on a chip. The respective unit on the LIDAR measuring system is preferably arranged in a focal point of a corresponding optics, transmitting optics or receiving optics. In particular, the sensor elements or the emitter elements are arranged in the focal point of the receiving optics. Such optics can be formed, for example, by an optical lens system.

The LIDAR receiver unit has several sensor elements, which are preferably designed as SPAD, single photon avalanche diode. The LIDAR transmitter unit has several emitter elements for emitting laser light, advantageously laser pulses. The emitter elements are advantageously designed as VCSELs, vertical cavity surface emitting lasers.

The transmission unit has emitter elements which are distributed over an area of the transmission chip. The receiving unit has sensor elements that are distributed over an area of the receiving chip. An optical transmitter is assigned to the transmit chip and an optical receiver is assigned to the receive chip. The optics represent a light arriving from a room area on the respective chip. The area corresponds to the field of view of the measuring system, which is examined or sensed for objects.

The spatial area of the transmitting unit and the receiving unit are essentially identical. The transmitting optics map an emitter element to a solid angle, which represents a partial area of the spatial area. The emitter element accordingly emits laser light in this solid angle. The emitter elements together cover the entire room area.

The receiving optics map a sensor element to a solid angle, which represents a partial area of the spatial area. The number of all sensor elements covers the entire room area. Emitter elements and sensor elements that consider the same solid angle map to one another and are accordingly assigned to one another. A laser light from an emitter element normally always maps to the associated sensor element. If necessary, several sensor elements are arranged within the solid angle of an emitter element.

The measuring system carries out a measuring process to determine objects within the spatial area. Such a measuring process comprises one or more measuring cycles, depending on the design of the measuring system and its electronics.

The Time Correlated Single Photon Counting method, TCSPC, is preferably used. In this case, individual incoming photons are detected, in particular by SPAD, and the time of the triggering of the sensor element, also the time of detection, is stored in a memory element. The time of detection is related to a reference time at which the laser light is emitted. The transit time of the laser light can be determined from the difference, from which the distance of the object can be determined.

A sensor element can be triggered on the one hand by the laser light and on the other hand by the ambient radiation. A laser light always arrives at a certain distance from the object at the same time, whereas the ambient radiation always provides the same probability of triggering a sensor element. If a measurement is carried out several times, in particular several measurement cycles, the triggering of the sensor element at the time of detection that corresponds to the transit time of the laser light with respect to the distance of the object, whereas the triggering by the ambient radiation is distributed evenly over the measuring duration of a measuring cycle. A measurement corresponds to the emission and subsequent detection of the laser light. The data of the individual measurement cycles of a measurement process stored in the memory element enable the multiple times of detection to be evaluated in order to infer the distance of the object.

A sensor element is expediently connected to a Time to Digital Converter, TDC, which stores the point in time at which the sensor unit is triggered in the memory element. Such one The storage element can be designed, for example, as a short-term storage or as a long-term storage. For a measuring process, the TDC fills a storage element with the times at which the sensor elements detected an incoming photon. This can be graphically represented by a histogram, which is based on the data of the storage element. In the case of a histogram, the duration of a measurement cycle is divided into short periods of time, so-called bins. If a sensor element is triggered, the TDC increases the value of a bin by one. The bin that corresponds to the transit time of the laser pulse, that is the difference between the detection time and the reference time, is filled.

One aspect of the invention relates to a vehicle or motor vehicle, for example a passenger car, which comprises a described LIDAR measuring system.

Further developments of the LIDAR measuring system relate to features of further developments as already described in connection with the locking device. A corresponding description is therefore omitted and the corresponding features are also considered to be disclosed in connection with the LIDAR measuring system.

• 1 eine schematische Darstellung einer Feststellvorrichtung mit einem magnetorheologischen Elastomer und einer Welle in freigegebenem, schwenkbarem Zustand;
• 2 eine schematische Darstellung der Feststellvorrichtung mit dem magnetorheologischen Elastomer und der Welle in festgestelltem Zustand;
• 3 eine schematische Seitenschnittansicht einer Feststellvorrichtung umfassend einen piezoelektrischen Ring;
• 4 einen schematischen Querschnitt einer Feststellvorrichtung mit einem piezoelektrischen Element;
• 5 eine schematische Darstellung eines LIDAR-Messsystems mit einer Feststellvorrichtung in Frontansicht; und
• 6 eine schematische Darstellung des LIDAR-Messsystems mit der Feststellvorrichtung in Seitenansicht.

Some examples of devices are only explained in more detail below with reference to the accompanying figures. Show it:

• 1 a schematic representation of a locking device with a magnetorheological elastomer and a shaft in the released, pivotable state;
• 2nd a schematic representation of the locking device with the magnetorheological elastomer and the shaft in the determined state;
• 3rd is a schematic side sectional view of a locking device comprising a piezoelectric ring;
• 4th a schematic cross section of a locking device with a piezoelectric element;
• 5 a schematic representation of a LIDAR measuring system with a locking device in front view; and
• 6 a schematic representation of the LIDAR measuring system with the locking device in side view.

1 shows a schematic representation of an exemplary locking device 10th . The locking device 10th is shown in an assembled state in which a body to be fixed 11 which is a mechanical shaft 11a includes, in the locking device 10th is recorded. The locking device 10th comprises a device 12th to generate a magnetic field, which is a coil 12a has, as well as two deformable materials 13 or elements made of magnetorheological elastomer 13a include. The deformable material 13 is in a respective recess 15 of a basic body 16 who is an iron yoke 16a comprises, arranged.

On one side 14 of the deformable material 13 going to the wave 11a points, a locking element can be arranged. The deformable material 13 can in the recess 15 be inserted, for example by axial delimitation of the base body (not in 1 shown) and the recorded wave 11a the deformable material falling out of the recess 15 is prevented. For example, the deformable material is at a radially outer interface 17th the recess 15 attached to the base body, eg glued.

In 1 is the magnetorheological elastomer 13a in one towards the wave 11a , ie radial direction, shown contracted state, ie the shaft 11a is in a released, swiveling state. A current flow through the coil 12a can create a magnetic field within the magnetorheological elastomer 13a cause an expansion of the magnetorheological elastomer 13a in the circumferential direction and contraction of the magnetorheological elastomer 13a in the radial direction.

2nd shows a schematic representation of the locking device 10th with the magnetorheological elastomer 13a and the wave 11a in ascertained condition. The sink 12a is de-energized, so there is no magnetic field in the magnetorheological elastomer 13a is generated and contraction of the magnetorheological elastomer 13a in the circumferential direction and a corresponding expansion in the radial direction is effected. As a result, the magnetorheological elastomer jams 13a between the interface 17th the recess 15 and an outer surface of the mechanical shaft 11a firmly so that there is a braking force on the mechanical shaft 11a that exerts a rotation of the mechanical shaft 11a prevented.

1 and 2nd in other words show an MRE (magnetorheological elastomer) ring for fixing the position after adjustment of a body. The ring can directly on the shaft to be held 11a Eg next to a shaft bearing. The coil is in the de-energized state 12a the inner diameter of the ring is so small that the ring holds the shaft. Should the adjustment unit the wave 11a rotate or reposition, the ring element is controlled electrically, for example by a current flow through the coil 12a , which increases its inner diameter and releases the shaft. As soon as the positioning has taken place, the ring is no longer activated and fixes the shaft again in the set position. The ring element comprises an MRE insert, which changes the resulting inner diameter of the ring when the magnetic field is appropriately aligned. The guide of the from the coil 12a generated magnetic field takes place over the Eisenjoch 16a .

3rd shows a schematic side sectional view of a locking device 30th comprising a piezoelectric ring 33 . The piezo ring 33 is on a housing 32a with a shaft bearing 32 in which a mechanical shaft 31 is recorded, attached. For example, the locking device 30th in the housing 32a inserted or screwed to this. A radial extension of the ring 33 can result, for example, from an axially or radially directed electric field, which can be generated by applying a voltage between outer surfaces of the ring.

The piezo ring 33 is, for example, directly on the shaft to be held 31 next to a warehouse 32 the wave 31 stuck. A simple assembly of the locking device is thus made possible. The inner diameter of the ring is in the de-energized or de-energized state 33 so small that the ring 33 the wave 31 holds on. Should an adjustment unit the shaft 31 turn or reposition, the piezo ring 33 controlled, whereby this increases its inner diameter and the shaft 31 releases. Once the positioning is done, the ring 33 no longer controlled and fixes the shaft again 31 in the set position. A piezo clamping element is therefore shown for fixing the position after adjusting an element.

4th shows a schematic cross section of an alternative locking device 40 with a piezoelectric element 42 . A basic body 44 is about a wave 41 arranged around. The main body 44 in a circumferentially expanded state of the piezoelectric element 42 an inner diameter that is larger than a diameter of the shaft 41 . By changing the voltage on the piezoelectric element 42 this contracts and thereby causes the main body 44 the wave 41 stuck. For example, the main body 44 through a mechanical joint 43 that versus the piezoelectric element 42 is arranged to be movable. An inside of the body 44 can be rough to create a higher friction on the shaft 41 to be able to transfer. Alternatively, instead of the joint 43 a further piezoelectric element can be arranged that is analogous to the first piezoelectric element 42 is controlled.

5 shows a schematic representation of a LIDAR measuring system 50 with a locking device 10th in front view. A swiveling element 50a of the LIDAR measuring system 50 exhibits a mechanical shaft 11a on that in bearing bracket 51 is included, so that the pivotable element 50a by turning the mechanical shaft 11a can be pivoted. At least on a bracket 51 is a locking device 10th arranged the the mechanical shaft 11a encloses. A locking device can also be arranged on each of the two mounting brackets, for example by a higher locking force on the pivotable element 50a to effect. A more detailed view of the locking device 10th is in 6 shown.

6 shows a schematic representation of the LIDAR measuring system 50 with the locking device 10th in side view. An iron yoke 16a the locking device 10th is about the mechanical shaft 11a arranged. Around the Eisenjoch 16a is a coil 12a which wrapped a magnetic field in one or more magnetorheological elastomers 13a the locking device 10th can generate. If the locking device 10th no locking force on the mechanical shaft 11a exercises, the pivotable element 50a can be positioned or adjusted, for example, by rotating the mechanical shaft 11a is set. If a predetermined positioning is adopted, the locking element can 10th the mechanical shaft 11a lock or hold so that the set positioning of the pivoting element 50a is maintained.

The locking device according to the invention makes it possible, for example in systems with limited installation space, to determine or fix a movable element, such as a pivotable mechanical shaft, in a predetermined or adjusted position with low energy consumption. In particular, a stepless or gridless fixation can be made possible.

Reference list

10th

Locking device

11

body to be determined

11a

mechanical shaft

12th

Device for generating a magnetic field

12a

Kitchen sink

13

deformable material

13a

magnetorheological elastomer

14

Side surface

15

Recess

16

Basic body

16a

Eisenjoch

17th

Interface

30th

Locking device

31

wave

32

Shaft bearing

32a

casing

33

Piezo ring

40

Locking device

41

wave

42

piezoelectric element

43

mechanical joint

44

Basic body

50

LIDAR measuring system

50a

swiveling element

51

Bearing bracket

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• WO 2017/081294 A1 [0026]

Claims (9)

Locking device (10, 30, 40), the locking device (10, 30, 40) being designed, depending on the operating mode of the locking device (10, 30, 40), a rotational movement and / or linear movement of the body (11, 11a) to be locked to prevent or enable. Locking device (10, 30, 40) according to Claim 1 , wherein the deformable material (13) comprises a magnetorheological elastomer (13a) which expands or contracts in one direction depending on an acting magnetic field. Locking device (10, 30, 40) according to one of the preceding claims, wherein the deformable material (13) is received in a respective recess (15) of a base body (16) of the locking device (10), with an extension of the recess (15) in an expansion direction of the deformable material (13) is smaller than an extension of the deformable material (13) in an expanded state of the deformable material (13). Locking device (10, 30, 40) according to one of the preceding claims, wherein the deformable material (13) is inserted into the recess (15) or at least on an interface (17) of the recess (15) provided by the base body (16) Base body (16) is attached. Locking device (10, 30, 40) according to one of the preceding claims, wherein a locking element is arranged on a side surface (14) of the deformable material (13), which comprises a material different from the deformable material (13). Locking device (10, 30, 40) according to one of the preceding claims, further comprising: a hollow cylindrical base body (16) which comprises a magnetic material at least in regions; and at least one coil winding (12a) for generating the magnetic field, which acts on the deformable material (13), the coil winding (12a) being wound around the base body (16) in a partial area of the base body (16). Locking device (10, 30, 40) according to one of the preceding claims, wherein the deformable material (13) comprises piezoelectric material which, when the electric field is generated in the deformable material (13) by applying an electrical voltage, causes a change in the expansion of the deformable material (13) causes. Locking device (10, 30, 40) according to one of the preceding claims, wherein the deformable material (13, 33) is formed by a hollow cylindrical element (33) and an inner diameter of the deformable material (13) from one to the deformable material (13) Applied voltage depends or wherein the deformable material (13, 42) is arranged at least in a peripheral region of a hollow cylindrical base body (44), so that a change in length of the deformable material (13, 42) in the circumferential direction of the base body (44) results in an inner diameter of the base body (44) changed. A LIDAR measuring system (50) with at least one pivotable element which is pivotably mounted on a mechanical shaft (11a), comprising a locking device (10, 30, 40) according to one of the preceding claims, which is arranged on the shaft (11a) , The locking device (10, 30, 40) on a bearing bracket (51) or housing part of the LIDAR measuring system (50), in which the shaft (11 a) is received, is fastened, the shaft (11 a) in one first state of expansion of a deformable material (13) of the locking device (10, 30, 40) is determined by means of the locking device (10, 30, 40) and in a second expansion state of the deformable material (13) is released for pivoting the pivotable element.

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