DE102006043615A1 - Obstacle i.e. jamming situation, detecting method for opening region of e.g. trunk lid opening, involves determining and analyzing actual reflectance coefficient, actual phase position and running time of light beam of opening region - Google Patents

Abstract

The method involves scanning, radiating and receiving a light beam (Ls) of an opening region (1) of a lockable opening (2), and determining and analyzing an actual reflectance coefficient, an actual phase position and a running time of the light beam. The reflectance coefficient and/or the phase position are analyzed based on a reference reflectance coefficient and/or reference phase positions for a preset reference point. A reflector arranged within the opening region and opening edges (4.1-4.4) are used as a reference point. An independent claim is also included for a device for detecting an obstacle within an opening region of a lockable opening.

Description

The The invention relates to a method and a device for detecting an obstacle in an opening area a closable opening, in particular for one preferably early Detection of pinching situations with electrically driven adjusting drives in motor vehicles such as e.g. Hood, windows, trunk lid, sliding doors and sunroofs to open or close from relevant openings also for various pinching situations with electrically driven seat adjustment devices.

For adjusting drives, the different openings close, There are various regulations and guidelines, such as the 74/60 / EEC the European Union, the EC21 of the UNECE (United Nations Economic Commission for Europe), the FMVSS118 from the American National Highway Traffic Safety Administration. All of these regulations require certain operating and test conditions a limitation of the clamping force to a maximum of 100 Newton. Especially should a 4 mm test rod still be recognized as an obstacle.

Out In the prior art methods are known which the load evaluate a drive or servomotor and thus indirectly on close a trap, when the load of the engine over an expected amount goes out. These indirect methods have the disadvantage that actually a Einklemmkraft must be established and in the system a current Load profile must be stored in order to exceed a maximum permissible To detect clamping force. About that In addition, it is necessary to know the position of the Verstellantriebs. This is realized according to the prior art by means of additional Hall sensors on the engine.

Direct methods are for example from EP 1 082 513 B1 known, are arranged in the contacts in the sealing rubber. Furthermore, methods are known which are based on ultrasound (eg EP 1 002 922 A2 ), or optically work according to the light barrier principle to detect an obstacle before a contact and thus a trapping case occurs. In the known, indirect methods, a possible pinching is recognized only after a clamping force has been built up. For many applications in the comfort sector, however, it would be desirable to have a direct anti-trap protection, for example to prevent injury when closing trunk lids, (sliding) doors, lifting and sliding roofs. But also in the scope of the classical indirect anti-pinch protection, a direct method would be advantageous because a non-contact and thus 0-force detection seems possible.

at the direct procedures are about it In addition, ultrasonic methods known, but when wet to malfunction tend. There are also materials, especially certain textiles, which essentially absorb the waves, leaving only one minimal reflection occurs. The same applies to the optical method according to the light barrier or reflection principle. All previously known, Direct-working principles is common to small objects (4 mm rod) can only be detected with insufficient safety, in particular, when the test rod located on an edge of the mechanism.

Of the The invention is therefore based on the object, a non-contact and force-free method and apparatus for detecting a Obstacle in an opening area indicate a closable opening.

Regarding of the method, the object is achieved by the features of the claim 1. With regard to the device, the object is achieved by the features of claim 12. Advantageous developments of the invention are the subject of the dependent claims.

At the inventive method for detecting an obstacle in an opening area of a closable opening a ray of light the opening area, in particular point by point broadcast and received. Subsequently, will its current reflectance and / or current phase angle and / or Running time determined and analyzed. With the method according to the invention can a pinch protection can be realized without causing a touch or even a structure of a clamping force comes (so-called zero force anti-jamming). This is done by means of optical, preferably collimated radiation and reflection this at a given scanning edge and the subsequent reflection, Runtime and / or Phase measurements. Due to the preferably bundled irradiation of the opening to be monitored or closing range can also very small objects, eg. B. 4 mm thick test rods or children's fingers, sure and be recognized quickly. Especially the fast detection is important for openings, which can be closed by drives in a very short time (like about sliding doors).

Expediently, the current reflectance and / or the current phase angle are analyzed on the basis of stored and / or preceding reference reflection levels and / or reference phase positions for predetermined reference points. For this purpose, the light beam to be emitted is directed to one or more predetermined reference points and reflected by them. Differs the currently determined reflectance or the currently determined phase position or the currently determined duration for a reference point from the stored and / or previous reference value for the reference point concerned, an obstacle is identified. Such a comparative analysis allows a quick and reliable detection of a possible trapping case. As a reference point, a reflector arranged in the opening area is preferably used. Alternatively or additionally, the circumferential or a part of the peripheral opening edge can be used as a reference point. For this purpose, the reflector or the opening edge is designed to reflect the optical radiation in a corresponding manner. For example, the reflector or the opening edge itself is formed by a metal sheet or a metal foil. Also, the reflector and / or the opening edge may be provided with a reflective lacquer layer.

alternative or additionally may be based on the current reflectance and / or current Phasing and / or the current running time of the current opening degree or closing degree the opening be determined. For this purpose, for example, as the phase position Phase difference between emitted light beam and reflected Detected light beam. Based on the phase difference, the distance covered and thus the distance between the opening edge and the transmitting and receiving unit are determined. Here is the transmitting and receiving unit preferably at a fixed opening edge and opposite the closable opening edge arranged. For this purpose, the emitted light signal is modulated, preferably frequency modulated.

In the case of the light beam modulated with a frequency f = 1 / T, the phase difference φ and the transit time Δt result according to: φ = Δt / T · 2 and [1] the distance or the distance according to: d = c * T 4π · (Φ + 2π · n) [2]

alternative or additionally the distance can be determined by means of conventional absolute interferometry become. Here are relative phase changes between two or compared more optical rays, the interference pattern for measuring small changes angles and / or distances is being used.

In addition to Determining the distance between the transmitting and receiving unit and the opposite opening edge can with suitable execution the position of the adjusting mechanism and the relevant drive be determined, for example, based on runtime or Phase measurements between a moving and a fixed one Part of the opening.

ever according to type and design The device can be a strong beam as a light beam Beam, in particular be emitted continuously or pulsed. For example, visible light or invisible light, a Laser beam or an infrared light emitted. Also, the Light beam amplitude modulated. The optical transmitting unit is for example, as a laser diode or a strong focusing Light emitting diode or other suitable light source running, the a point-by-point scanning of the opening area allows. Furthermore a deflection unit is provided, for. B. a micromechanical mirror, which is periodically rotatable about at least one axis, or static is controllable.

embodiments The invention will be explained in more detail with reference to a drawing. In this demonstrate:

1 schematically a device for detecting an obstacle in an opening region of a closable opening without obstruction in the opening area,

2 schematically the device according to 1 with an obstacle in the opening area,

3 schematically a possible structure of a device according to 1 with a transmitting and receiving unit and an evaluation unit,

4 various timing diagrams showing the time course of the reflectance and the distance.

each other corresponding parts are in all figures with the same reference numerals Mistake.

1 shows the basic principle for scanning an opening area 1 an opening 2 , z. B. the opening of a window, a trunk, a sliding door, a sunroof in a vehicle. The basic principle is described below using the example of a sliding door.

In this case, a collimated light beam Ls by means of a device 3 (also called scanning unit or scanner unit) along a predetermined contour on opening edges 4.1 to 4.4 in the opening area 1 directed broadcast. In this case, the predetermined scanning contour is selected so that the entire opening area 1 is covered and the opening edges 4.1 to 4.4 form a reference with associated predetermined reference points R. The device 3 is to be scanned at an opening edges 4.1 to 4.2 opposite and fixed opening edge 4.3 respectively. 4.4 , z. In the Area of the roof pillar and / or the B pillar of the vehicle, arranged. The opening edge 4.2 represents a movable opening edge of the movable in the direction of arrow P1 sliding door. The emitted light beam Ls scans the opening area 1 along the respective opening edges 4.1 to 4.2 completely and pointwise. During this scanning, the reflected and the device will be used 3 received light beam Lr as information the reflectance, the term and / or the phase position determined. The reflectance represents the ratio of the directionally reflected radiation power to the incident radiation power. The transit time can be determined in a conventional manner. In addition, the emitted light beam Ls can be periodically modulated at a predetermined frequency. The received reflected light beam Lr is superimposed on the emitted light beam Ls. Based on a resulting difference signal, in particular the phase difference φ according to the above equations [1] and [2], the distance d can then be determined. Alternatively or additionally, the delay Δt can be determined. In this case, the signal for the transit time measurement can be modulated differently: pulse modulation and periodic modulation of the signal amplitude. In the periodic modulation of the amplitude, the delay Δt results from the phase shift of the outgoing and incoming signal.

The device 3 is, for example, as a fixed scanner unit for selective distance and reflection measurement for a quick detection of a small obstacle in the opening area 1 executed. In 1 is no obstacle in the opening area 1 , in 2 is a relatively small obstacle 5 in the opening area 1 arranged.

3 shows the device 3 in detail. The device 3 comprises a transmitting unit for emitting the light beam Ls 6 , z. B. a suitable light source, such as a laser diode. For scanning the opening area 1 is the sending unit 6 a deflection unit 7 downstream of the radiation output side. As a deflection unit 7 For example, a micromechanical mirror is used which can be moved periodically about at least one axis or is statically controllable. By controlling the deflection unit 7 becomes the opening area 1 completely scanned. The at the opening edges 4.1 to 4.2 and / or at the predetermined reference points R reflected light beam Lr is by means of a receiving unit 8th receive. To modulate or demodulate the emitted light beam Ls or the reflected light beam Lr are an associated modulation unit 9 or demodulation unit 10 the transmitting unit 6 or the receiving unit 8th upstream or downstream. For modulating the emitted light beam Ls with a predetermined modulation frequency is a reference oscillator LO with the modulation unit 9 connected. The transmitting unit 6 is connected to a supply unit U. The analysis of the reflected light beam Lr on the basis of the emitted light beam Ls takes place by means of an evaluation unit 11 , z. B. a microprocessor. Depending on the type and design of the device 3 this can include all components as an integrated circuit. Alternatively, the transmitting and receiving unit and the evaluation unit can be designed to be integrated separately or in another way.

The evaluation unit 11 includes a storage unit 12 in which the scanning contour of the opening area 1 for the time control of the deflection unit 7 by means of controls 13 is deposited. In addition, the evaluation unit includes 11 another memory module 14 , in which previous phase and / or transit time measurements as well as reflection degrees or reference phase and / or reference transit time measurements and reference reflection degrees are stored.

For each point of the scanning contour of the opening area 1 is a distance signal d (t) and a reflection signal r (t) by means of the receiving unit 8th detected and via an amplifier unit 15 strengthened and the evaluation unit 11 fed. By comparing the current transit time or phase measurement with a reference measurement or previous transit time or phase measurements for predetermined reference points R, a possible pinching situation can be reliably detected. If the current transit time or phase measurement deviates from the expected reflection and / or phase progression, ie from reference values or previous runtime or phase measurements, by a predetermined limit value, an existing or occurring obstacle will become 5 in the opening area 1 identified. Identification takes place by means of the evaluation unit 11 , The evaluation unit 11 may, upon identification of a possible Einklemmfalls a control signal of a motor adjustment 16 respectively. This is the evaluation unit 11 with the engine adjusting device 16 connected. By means of the engine adjusting device 16 an actuator is preferably stopped or reversed in its closing movement to avoid a pinching situation. At the engine adjusting device 16 it can be an indirect anti-jamming device with a motor as a torque sensor. Alternatively, it may be a direct anti-trap with a separate sensor for the pinching force.

In contrast to known solutions according to the light barrier principle can be operated by the operating according to the laser radar principle device 3 even very small objects or obstacles 5 be recognized because of the selective illumination light from exactly one direction for evaluation ge reached. If a laser in the visible light range or in the infrared light range is used as the light source, light spots in the range of a few mm and less are possible due to the special properties of the laser, even at relatively long distances. However, the use of a laser is not absolutely necessary, depending on the requirements of the object sizes to be recognized are less heavily focused light sources, eg. B. a light emitting diode as a transmitting unit 6 , possible.

4 Using different timing diagrams for different function curves and different situations, shows why conventional optical methods are flawed in the fast detection of small objects. As situations, the case (a) is without obstacle in the opening area 1 and the case (b) with the obstacle 5 in the opening area 1 specified. The function curves represent the distance signal d (t) determined on the basis of the transit time and / or phase measurement and the conventionally determined reflectance r (t). The reflectance r (t) of the obstacle 5 may have a substantially same reflectance r (t) as the background, ie the opening edges to be probed 4.1 to 4.2 exhibit. Thus, the reflection signal r (t) no clear information about a possible obstacle 5 supply, even if the illumination is not punctiform but over large solid angles. To an obstacle 5 can be identified with a conventional method, the measuring time is to be chosen so large that small changes in the received signals can be detected, but this runs counter to the requirement for rapid detection. Thus, at time t _1, a particularly highly reflective object is to be identified, which in the example is not the obstacle 5 represents. The obstacle 5 due to its low reflectivity causes a barely measurable change in the reflection signal r (t) at time t ₂ . By contrast, a distance signal d (t) at time t ₂ can be determined by means of the method according to the invention on the basis of the transit time and / or phase measurement, which deviates clearly from the reference signal at the relevant reference point R and thus the identification of the obstacle 5 allows.

Preferably, the scanning contour is predetermined so that the opening area 1 illuminated as completely as possible and the resulting closing range of the adjustment is monitored on the basis of the determined distance value. Depending on the available closing time and closing position, different areas of the adjusting drive can be measured with greater accuracy, for example to obtain position information, or to cover shear zones with greater safety. In addition, the scanning contour can be selected such that not only the closing area itself, but also a scanning of the nearer surroundings via the opening edges 4.1 to 4.4 takes place. In this way, for example, an impending pinching situation can already be identified in advance.

1

opening area

2

opening

3

contraption

4

Opening edges ( 4.1 to 4.4 )

5

obstacle

6

transmission unit

7

Deflector

8th

receiver unit

9

modulator

10

demodulator

11

evaluation

12

storage unit

13

control unit

14

memory module

15

amplifier

16

Motorverstelleinrichtung

a

opening degree

d

distance

ls

emitted beam of light

Lr

reflected beam of light

r

reflectance

Claims (19)

Method for detecting an obstacle ( 5 ) in an opening area ( 1 ) a closable opening ( 2 ), wherein a light beam (Ls) the opening area ( 1 ) is scanned and received and whose current reflectance (r (t)) and / or current phase position (φ) and / or transit time (Δt) are determined and analyzed. The method of claim 1, wherein the current reflectance (r (t)) and / or the current phase position (φ) based on stored reference reflection levels and / or reference phase positions for given Reference points (R) are analyzed. Method according to claim 2, wherein as reference point (R) at least one in the opening region ( 1 ) arranged reflector and / or an opening edge ( 4.1 to 4.4 ) is used. Method according to one of the preceding claims, wherein the current reflectance (r (t)) and / or the current phase angle (φ) on the basis of previous determined reflection levels (r (t)) and / or phase positions (φ) for given reference points to be analyzed. Method according to one of the preceding claims 1 to 4, wherein in a change of the ak tual phase position over a predetermined limit value or a limit value profile, a control signal for an engine adjusting device ( 16 ) is triggered. Method according to one of the preceding claims 1 to 5, wherein based on the determined phase position (φ), the current closing state of the opening ( 2 ) Closing adjustment mechanism is determined. Method according to one of the preceding claims 1 to 6, wherein as the phase position, the phase difference (φ) between emitted light beam (Ls) and received light beam (Lr) is determined. Method according to one of the preceding claims 1 to 7, wherein the light beam (Ls) pulse, amplitude and / or frequency modulated is. Method according to one of the preceding claims 1 to 8, wherein the emitted light beam (Ls) on at least one predetermined reference point (R) is directed. Method according to one of the preceding claims 1 to 9, wherein the light beam (Ls) a to the opening area ( 1 ) scans adjacent area. Method according to one of the preceding claims 1 to 10, wherein as a light beam (Ls) a highly focused beam, in particular is emitted continuously or pulsed. Contraption ( 3 ) for detecting an obstacle in an opening area ( 1 ) a closable opening ( 2 ), comprising an optical transmitting unit ( 6 ) and receiving unit ( 8th ), which has a light beam (Ls) the opening area (Ls) 1 ) emits and receives again, and an evaluation unit ( 11 ), which determines and analyzes the current reflectance (r (t)) and / or the current phase position (φ) and / or the current transit time (Δt) on the basis of the emitted and received light beam (Lr). Apparatus according to claim 12, wherein as transmitting unit ( 6 ) A laser diode or a strong focusing light emitting diode is provided. Apparatus according to claim 12 or 13, wherein as receiving unit ( 8th ) a CCD sensor or one or more photodiodes serve or serve. Device according to one of the preceding claims 12 to 14, wherein the opening area ( 1 ) is provided with at least one reflector which marks a predetermined reference point (R). Apparatus according to claim 15, wherein as a reflector a metal sheet, a metal foil and / or a reflective lacquer layer serve or serve. Device according to one of the preceding claims 12 to 16, wherein the evaluation unit ( 11 ) with an engine adjustment device ( 16 ) and / or with an opening ( 2 ) Closing adjustment mechanism is connected. Apparatus according to claim 17, wherein the engine adjusting device ( 16 ) comprises for an indirect anti-jamming a servomotor serving as a torque sensor. Device according to claim 17 or 18, wherein the engine adjusting device ( 16 ) for a direct anti-trap a separate sensor and a servomotor comprises.