CN104411548A

CN104411548A - Method for detecting and processing measurement values of a capacitive proximity sensor for initiating an operating function of a tailgate of a motor vehicle comprising an energy-saving evaluation mode

Info

Publication number: CN104411548A
Application number: CN201380035924.9A
Authority: CN
Inventors: 贝特霍尔德·西格; 米尔科·辛德勒; 马库斯·菲尔鲁特; 皮特·克莱门斯
Original assignee: Huf Huelsbeck and Fuerst GmbH and Co KG
Current assignee: Huf Huelsbeck and Fuerst GmbH and Co KG
Priority date: 2012-07-27
Filing date: 2013-07-04
Publication date: 2015-03-11
Anticipated expiration: 2033-07-04
Also published as: EP2877376B1; DE102012106851A1; EP2877376A1; WO2014016097A1; CN104411548B

Abstract

In a method for detecting and processing measurement values of at least one capacitive proximity sensor which is arranged in the rear region of a motor vehicle close to the ground and for initiating an operating function of a tailgate by a prespecified foot movement of an operator, a measurement value of the proximity sensor is periodically detected after in each case one scanning interval, and a digital measurement value which corresponds to the measurement value is stored in a FIFO memory. In a first, energy-saving evaluation mode, a filter value is calculated from the currently stored digital measurement value and a prespecified second number of previously stored digital measurement values, in each case after a prespecified first number of digital measurement values are stored, by each of said stored digital measurement values being multiplied by an associated first factor in each case and the results being added, the filter value being compared with the threshold value and a second evaluation mode being activated when the filter value exceeds the threshold value. In the second, normal evaluation mode, a filter value is calculated from the currently stored digital measurement value and a prespecified fourth number of previously stored digital measurement values, in each case after a prespecified third number of digital measurement values, which third number is smaller than the first number, are stored, by each of said digital measurement values being multiplied by an associated second factor in each case and the results being added, and the filter value being fed to an algorithm for identifying a signal profile which corresponds to the prespecified foot movement.

Description

Be used for detecting and the method for observed reading of process capacitive proximity sensor, to carry out the operating function of the boot compartment of trigger unit motor-car by energy-conservation evaluation profile

Technical field

The present invention relates to a kind of being used for detect and process the method that at least one is arranged on the observed reading of the capacitive proximity sensor in the tail region on the close ground of self-propelled vehicle, to be triggered the operating function of boot compartment by the foot motion preset of operator, wherein periodically detect the observed reading of capacitive proximity sensor by the sampling interval respectively, and the digital measured value being equivalent to this observed reading is stored in FIFO-memory device, and the digital measured value of this storage is transferred to algorithm, to identify the signal consistent with the foot motion preset of operator to move towards.

Background technology

It is known that, in the tail region on the close ground of self-propelled vehicle, (such as after plastic sunscreen plate) arranges the electrode of capacitance-type sensor like this, if namely stand in the pin that self-propelled vehicle operator below swings him in short time on the direction of tail region and in the below of tail region, then its electric capacity is made to change relative to reference potential (such as bonding).The electrode of capacitance-type sensor is coupled with evaluation circuits, this evaluation circuits by be equivalent to electric capacity, simulation output signal be sent on the A/D-conv of microcontroller.This microcontroller carrys out setting program like this, and namely it impels numerical value that A/D-conv periodically sends simulation, that be equivalent to sensor output signal, after this numerical value is called digital measured value.This digital measured value periodically (such as interval 20ms) produces, and this digital measured value is equivalent to the electric capacity of capacitance-type sensor.Assess the change of digital measured value, wherein the such setting program of this microcontroller, namely it can identify by the change of digital measured value, whether there occurs specific event, and whether the pin of such as operator is close.If microcontroller is determined at this, there occurs specific event, so it is just had a sudden inspiration the operating function of motor-car boot compartment.If therefore standing in self-propelled vehicle operator below puts under vehicle tail by pin in a particular manner, then boot compartment can be opened.In order to identify this motion preset better, preferably level and vertically two sensing electrodes are offsettingly set in a particular manner.Sensing electrode that it such as refers to longitudinal extension, that be made up of the external conductor of coaxial cable, it in tail region, extend substantially transversely to longitudinal direction of car direction and mutually vertical and Horizontal offset arrange.Schematically figure 1 illustrates this layout.

Usually the digital measured value detected with short time gap is stored in the storage area of the RAM of microcontroller.Employ this digital measured value with before realizing further process at the microprocessor of microcontroller, the digital measured value of predetermined quantity is cushioned in this storage area.First described further process comprises carries out digitalisation filtration to the digital measured value of the storage of predetermined quantity, therefore to obtain digital filter value to realize further process.This filter value calculates at the same time, in these time gaps, also obtain digital measured value.If store new digital measured value, then microprocessor calculates new filter value from this and the prior digital measured value stored.

In order to save energy, for identifying the signal of the predetermined motion of the body part characterizing operator, all further should not assess this filter value when the filter value that each appearance is new, but only have when meeting standard and just assess, this standard can assess the cost by a small amount of and therefore determine by a small amount of energy ezpenditure.In order to reduce energy ezpenditure, such as, in energy saver mode, determine digital measured value with larger spacing (less sampling frequency).From this digital measured value and from several in advance to determine filter value respectively the digital measured value of less sampling frequency acquisition.In order to simplify calculating, this filter value only compares with threshold value, and what therefore show this filter value by the confirmable standard that assesses the cost on a small quantity exceeds situation.Exceed as long as this threshold value is not filtered value, then obtain digital measured value, and calculate filter value, and repeatedly compare with this threshold value, this energy consumed is relatively less.But once filter value is beyond threshold value, then regard this point as standard, namely operator's body part there occurs the motion preset.So, this device is transformed into higher sampling frequency, namely digital measured value obtains with shorter spacing and again filters subsequently.But if the digital measured value of predetermined minimum number is again obtained with higher sampling frequency, and be stored in buffer memory, then can again start this filter process.The digital measured value obtained with lower sampling frequency in advance can not be listed in after-treatment.After this threshold value detected surmounts situation, this point can cause certain standing time, can't calculate the first filter value during this period, and this first filter value is the foot motion whether carrying out presetting to assess and analyze operator further.

Summary of the invention

Therefore the object of the invention is, create a kind of method being used for detecting and processing observed reading, the method allows the foot motion preset identifying operator quickly, is not easily disturbed the impact of situation simultaneously.

By the present invention, this object is achieved by the method for the feature with claim 1.

In this method periodically respectively by the observed reading of sampling interval detection capacitive proximity sensor, and the digital measured value being equivalent to observed reading is stored in FIFO-memory device, the method is used to detection and processes the method that at least one is arranged on the observed reading of the capacitive proximity sensor in the tail region on the close ground of self-propelled vehicle, to be triggered the operating function of boot compartment by the foot motion preset of operator.FIFO-memory device can be such as the parts of the memory device of independent component or microcontroller.In the first energy-conservation evaluation profile, respectively after the digital measured value storing the first predetermined quantity, namely after the time gap of product being equivalent to sampling period time length and the first quantity, from the digital measured value of current storage and the digital measured value of the prior storage of the second quantity preset, calculate filter value, its mode is: the digital measured value of each storage is multiplied with affiliated factor I respectively and adds this result.Then filter value and threshold value are compared.If filter value has exceeded threshold value, then activate the second evaluation profile.In the second normal evaluation profile, respectively after the digital measured value storing predetermined the 3rd quantity (it is less than the first quantity), namely in shorter time gap, filter value is calculated from the digital measured value of current storage and the digital measured value of the prior storage of the 4th quantity preset, its mode is: the digital measured value of each storage is multiplied with affiliated factor Ⅱ respectively and adds this answer, and filter value is transferred to algorithm, to identify the signal trend of the foot motion preset being equivalent to operator.

This way is favourable, namely sampling frequency (sampling frequency) or sampling period time length remain unchanged in the one the second evaluation profiles, therefore need not after the second evaluation profile starts when exceeding threshold value by the sampled value of the sampling frequency of change to refill FIFO-memory device.Although first higher sampling frequency can consume more energy to realize the intermediate storage in A/D-conversion and FIFO-memory device, this point is by better filtering possibility to balance.In addition, in the first energy-conservation evaluation profile, these filter value are obtained with the spacing that evaluation profile more normal than second is larger.That is, this filtration calculates needs less energy in energy saver mode.Temporary (buffering) digital measured value also can utilize in a second mode rapidly further, allow to start described algorithm rapidly by this point, to identify the signal trend of the foot motion preset being equivalent to operator, and therefore to detect this answer quickly.

First quantity preset of digital measured value is preferably equivalent at least twice of the 3rd quantity preset of digital measured value.First numerical value is larger, then the energy saved is more, calculates because filter and seldom carries out with the contrast that threshold value is carried out.Certainly this interval does not allow so big, namely there is the danger " ignored " by the signal intensity of the foot motion the preset triggering of operator.In one embodiment, first quantity preset of digital measured value, between 4 and 16, preferably equals 8.

Be used for detecting and processing in the embodiment of observed reading, the second quantity equals the 4th quantity, and it is equivalent to the memory depth of FIFO-memory device.It such as equals 32.In this embodiment, both in the first energy-conservation operational mode, also in the second normal operational mode, always utilized whole memory depths fully, to obtain as far as possible good filter effect.

In a preferred embodiment, the sampling interval, in the scope of 1ms and 10ms, preferably in the scope of 2ms and 6ms, such as, is about 4ms.For the respective numbers of the observed reading be included, (calm down and suppress excitement) can be moved towards by trap signal well by this sampling interval, to identify the signal trend of the foot motion preset being equivalent to operator subsequently.

In improvement project of the present invention, factor Ⅱ and factor I are different, this factor Ⅱ determines the filtration types in the second evaluation profile, factor I determines the filtration types in the first evaluation profile, and therefore these observed readings differently can be filtered in the first and second evaluation profiles.Therefore, first filters and can match with the more low frequency of the generation of filter value, and matches with this task that detection threshold surmounts.Second filters and can match with the higher frequency of the generation of filter value, and matches with following task, namely identifies the signal consistent with the foot motion preset of operator and moves towards.

4th quantity (being included in the quantity of observed reading in filtration, that store in advance) and factor Ⅱ (coefficient of filteration) are preferably so selected, namely filter out the signal in following frequency limit with strengthening, this frequency limit is equivalent to the frequency limit of the appearance when operator carries out foot motion of capacitance variations.This point preferably reaches the frequency limit of 5Hz.

The feature of preferred improvement threshold of the present invention is, detect the observed reading of two biased capacitive proximity sensors arranged in a vehicle longitudinal direction, and the digital measured value being equivalent to these observed readings is stored in two is subordinated in the FIFO-memory area of sensor.

In the first energy-conservation evaluation profile, be only preferably a calculating filter value in these two sensors and and threshold comparison, and for these two sensors calculate filter value and transfer to described algorithm in the second evaluation profile, to identify the signal trend of the foot motion preset being equivalent to operator.

Describe favourable and/or preferred improvement project of the present invention in the dependent claims.

Accompanying drawing explanation

The present invention is describe in detail below by the preferred embodiment shown in the accompanying drawings.Those figures show:

Fig. 1 shows the device implemented by method of the present invention in the diagram; And

Fig. 2 shows digital measured value in the diagram and obtains and filter the time flow calculated.

Detailed description of the invention

The observed reading of the capacitive proximity sensor in the tail region of self-propelled vehicle is arranged on by method detection of the present invention and process.Fig. 1 shows the tail region 1 of self-propelled vehicle, and its in the region near ground (after anti-dazzle device) has electrode 2A and 2B of two capacitive proximity sensors.It preferably refers to the sensor cable of longitudinal extension, and it extends transverse to longitudinal direction of car direction, and the drawing namely transverse to Fig. 1 extends.Other device shown in Figure 1 just shows in order to clear the outside being just marked on self-propelled vehicle, but in fact it is arranged in a motor vehicle.Input cable 3 extends from sensing electrode 2A, 2B towards the evaluation circuits 4A of capacitance-type sensor and 4B respectively, and this evaluation circuits produces output signal that be equivalent to sensor capacitance, that simulate at its mouth, especially produces the voltage being equivalent to this electric capacity.These voltages being equivalent to the electric capacity of two sensing electrodes are transferred to the input port of microcontroller 5 respectively, and wherein analog to digital-conv 7A with 7B is connected with each input port.Microcontroller 5 comprises microprocessor 6, the ROM by storage running program, the RAM as working storage and other interface circuit, wherein schematically illustrates port one 1.Analog to digital-conv 7A, 7B and the circuit described in other are connected with microprocessor 6 by bus 9.Microprocessor 6 reads the observed reading of numeral by programming control ground from the storage thing of analog to digital-conv 7A, 7B and RAM8.In order to store digital measured value, in RAM8, be provided with specific storage area 12, digital measured value is stored in this storage area by FIFO-principle.The time controling situation of observed reading acquisition and after-treatment is determined by the program performed in microprocessor 6.

Fig. 2 illustrates the time flow that digital measured value obtains and filter value calculates by the preferred embodiment of method of the present invention.First microcontroller obtains a digital measured value for each sensor in all 4ms, and its mode is: impel A/D-conv to send corresponding digital measured value, then this digital measured value is stored in the FIFO-region 12 of RAM8.Accommodate 32 digital measured values of each sensor in the preferred embodiment that this FIFO-region 12 is shown herein.32 numerical value be stored in respectively in FIFO-region illustrate as little square in fig. 2, and are equivalent to the row of this view.Gap is equivalent to observed reading.The embodiment that the physics aspect of this FIFO-memory device is different also can be considered.Observed reading preferably keeps the time so grown respectively in storage area, until it is surmounted by new observed reading 32 detection observed readings.In FIFO-storage area around pointer determine, new observed reading can be write in which storage location respectively.

Fig. 2 illustrates other practice in the first energy-conservation evaluation profile.After 8 new digital measured values write in FIFO-storage area 12 respectively, filter value is calculated by microcontroller.Therefore, in all 8*4ms=32ms, filter value is calculated (implement to filter and calculate).But it is not 8 observed readings only comprising new last acquisition that the filtration carried out in all 32ms calculates, but comprises last 32ms.Therefore the observed reading of each storage altogether take part in for four times to filter and calculates.Decrease the situation of filtering and calculating and only carrying out in all 8ms on the one hand, namely decrease energy ezpenditure.All 32 digital measured values be stored in FIFO-region are all comprised to come in, can realize filtering more accurately on the other hand, especially suppress excitement.

In energy saver mode, the filter value obtained by this way and threshold value contrast.If definite threshold is surmounted, then activate the second evaluation profile.

The interval that filter value calculates is reduced in the second evaluation profile.Be such as that every 2 or 4 observed readings calculate filter value.The present filter value obtained with short spacing is transferred to algorithm, to identify the signal trend of the foot motion preset being equivalent to operator.

Such as carry out filtration by FIR-algorithm to calculate.At this, all 32 digital measured values are multiplied by a factor all respectively, and from product, obtain the summation consistent with filter value.In a preferred embodiment, the filter type in the first energy saver mode from be used for identifying that the filter type in the second normal mode of foot motion is different.This point also represents with different coefficient of filteration.These coefficient of filteration are such as selected like this in the second normal evaluation profile, be about to especially reach about 10Hz, preferably reach in the frequency limit of 5Hz signal trend filter out.Namely draw, the signal in these dark frequency limits particularly depict the motion to be detected of operator's body part (pin).In addition, these coefficient of filteration can match with each acquisition rate of filter value in the first and second modes.Therefore such as (respectively after 8 sampled values) acquisition filter value in all 32ms in the first energy-conservation evaluation profile, and their such as (though dividing after 2 sampled values) acquisitions in all 8ms in normal evaluation profile.

In the framework of theory of the present invention, also can consider a large amount of alternative embodiment.Therefore, these sampling periods such as can depart from 4ms, such as, in the scope of 1 to 10ms.The interval that filtration in first and second evaluation profiles calculates can change, and it is naturally important that, it is less in the second evaluation profile.Equally, the degree of depth of FIFO-memory device can depart from 32.

Claims

1. be used for detecting and processing the method that at least one is arranged on the observed reading of the capacitive proximity sensor in the tail region on the close ground of self-propelled vehicle, to be triggered the operating function of boot compartment by the foot motion preset of operator,

Wherein periodically detect the observed reading of capacitive proximity sensor by the sampling interval respectively, and the digital measured value being equivalent to this observed reading be stored in FIFO-memory device,

Wherein in the first energy-conservation evaluation profile, respectively after the digital measured value storing the first predetermined quantity, filter value is calculated from the digital measured value of current storage and the digital measured value of the prior storage of the second quantity preset, its mode is: the digital measured value of each storage is multiplied with affiliated factor I respectively and adds this result

Then filter value is compared with threshold value, if filter value has exceeded threshold value, then activates the second evaluation profile,

Wherein in the second normal evaluation profile, respectively after the digital measured value storing predetermined, less than the first quantity the 3rd quantity, filter value is calculated from the digital measured value of current storage and the digital measured value of the prior storage of the 4th quantity preset, its mode is: the digital measured value of each storage is multiplied with affiliated factor Ⅱ respectively and adds this answer, and

Filter value is transferred to algorithm, to identify the signal trend of the foot motion preset being equivalent to operator.

2. be used for detecting and the method for process observed reading by according to claim 1, it is characterized in that, first quantity preset of digital measured value is equivalent at least twice of the 3rd quantity preset of digital measured value.

3. by according to claim 2 be used for detect and process observed reading method, it is characterized in that, digital measured value preset the first quantity between 4 and 16.

4. by according to claim 3 be used for detect and process observed reading method, it is characterized in that, digital measured value preset the first quantity equal 8.

5. detect and process the method for observed reading by being used for described in Claims 1-4, it is characterized in that, the second quantity equals the 4th quantity, and is equivalent to the memory depth of FIFO-memory device.

6. detect and process the method for observed reading by being used for described in claim 1 to 5, it is characterized in that, in the scope of sampling interval between 1ms and 10ms.

7. by according to claim 6 be used for detect and process observed reading method, it is characterized in that, in the scope of sampling interval between 2ms and 6ms.

8. detect and process the method for observed reading by being used for described in claim 1 to 7, it is characterized in that, factor Ⅱ and factor I are different, and therefore these observed readings differently filter out in the first and second evaluation profiles.

9. detect and process the method for observed reading by being used for described in claim 1 to 8, it is characterized in that, 4th numerical value and factor Ⅱ are so selected, namely filter out the signal in following frequency limit with strengthening, this frequency limit is equivalent to the frequency limit of the appearance when operator carries out foot motion of capacitance variations.

10. detect and process the method for observed reading by being used for described in claim 1 to 9, it is characterized in that, detect the observed reading of two biased capacitive proximity sensors arranged in a vehicle longitudinal direction, and the digital measured value being equivalent to these observed readings is stored in two is subordinated in the FIFO-memory area of sensor.

11. by according to claim 10 be used for detect and process observed reading method, it is characterized in that, in the first energy-conservation evaluation profile, be only a calculating filter value in these two sensors and and threshold comparison, and all calculate filter value for these two sensors and transfer to described algorithm in the second evaluation profile, to identify the signal trend of the foot motion preset being equivalent to operator.