CN1323715A - Laser measurement method of moving attitude of vehicle - Google Patents

Abstract

A method of detecting vehicle movement posture by using laser, ground laser emission element is used to emit laser on the surface of detected moving vehicle, through detecting the laser light position or frequency change of the ground laser receiving element reflected back from the vehicle surface, the signal processing element can obtain the displacement or speed change of one point or several points on the vehicle from three directions during vehicle movement, thereby obtain the movement posture of vehicle. Said method is high in detecting precision, low in mechanical failure rate of detecting system, the train is not affected during detection.

Description

A kind of method of laser measurement moving attitude of vehicle

The present invention relates to a kind of rail vehicle athletic posture method for automatic measurement, be specially adapted in train movement, realize the athletic postures such as crawling, vibrate and rock of rail vehicle is carried out composite measurement by the ground laser detector, a kind of ways and means that detects the derail state is provided.

The athletic posture of rail vehicle is one of key factor that influences train traffic safety, particularly along with the development of China railways technology, the speed of train improves constantly, train is the key factor that is related to train safe and passenger comfort in the stationarity of circuit motion, and the crawling of vehicle, beat under the train high-speed cruising state, to rock and vibrate be the major cause that causes derail.How accurately to measure the athletic posture of train, avoid derail to guarantee that the traffic safety of train is that domestic and international railway scientific worker generally is concerned about but fails the technical barrier of fine solution.Method of measurement to moving attitude of vehicle has following several at present: rock instrument 1., on a joint vehicle, several acceleration pick-ups are installed, measure the situation of change of motion brief acceleration in this compartment, obtain the vibration in this joint compartment, situations such as beat, the major defect of this method is that the signal that obtains is the comprehensive of circuit and certain joint vehicle, can not judge the athletic posture of whole each vehicle of train, if will obtain the situation of a plurality of vehicles, must on each vehicle, load onto a cover system, it is [the track dynamic monitoring means development of extremely uneconomic way, Gan Dunwen etc., China Railway Association's academic annual meeting in 2000,338]; 2.CCD method of measurement, at rail installed inside CCD camera, the contact condition of measuring wheel and rail is in real time judged the athletic posture of train, thereby judge the possibility of derail, the shortcoming of this method is that the contact condition of wheel track can not reflect the athletic posture of train fully, more can not be as the judgement of derail possibility, and the speed of train can not the too high [Preliminary Applications of image technique in derailing research when measuring, State of Zhao's hall etc., railway construction, 1998 the 8th phases].

The objective of the invention is: provide the failure rate of machinery of a kind of survey precision height, measuring system low, the method for the unrestricted laser measurement moving attitude of vehicle of running velocity of train when measuring, realize measurement moving attitude of vehicle.

The object of the present invention is achieved like this, a kind of method of laser measurement moving attitude of vehicle: the laser that sends from the ground laser emission element is got to the surface of tested moving vehicle, by detecting from the surface of vehicle scattering to return and reach the laser beam position of laser pick-off unit, ground or the variation of frequency, when obtaining vehicle movement by signal processing unit, on the vehicle one or more in the displacement or the velocity variations situation of three directions, thereby obtain the athletic posture of vehicle.Moving attitude of vehicle ground laser measurement system comprises: laser emission element, laser pick-off unit and signal processing unit three parts.

Principle of measurement of the present invention is: when certain joint vehicle arrives laser measurement point, cause scattering to return to reach the variation of the frequency of photodetector owing to Doppler effect during vehicle movement; Perhaps because the motion of vehicle causes scattering to return to reach the variation of the light spot position of photodetector.Ideally, train needs only speed or the displacement along the rail direction, do not crawl, beat or vertical shake, the frequency change that this moment, detector obtained is the component relevant with Train's Longitudinal Movement only, the frequency variation of other direction is zero, and the position of the light that scattering is returned on photodetector can not change yet.Otherwise if automobile storage crawling, promptly laterally there is motion in vehicle, contains in the frequency change that this moment, detector obtained and the vehicle consistent frequency change component of direction that crawls; Or respective change can take place in the position that the scattering light of returning reaches photodetection, by detecting the variation of these frequencies or position, just can obtain the situation of crawling of train movement.

When the vibration of measuring vehicle vertical direction, one cover measuring system can be installed between two one steel rails, laser is got on the bottom surface of vehicle, by detecting in very short a period of time, just can obtain the situation of vehicle up-down vibration from the variation of light position on detector that vehicle bottom diverse location two point scattering are returned.

During the rocking of measuring vehicle, two cover measuring systems need be installed in the outside of circuit, make that the line of two laser spots of two cover system outgoing is parallel with the compartment vertical direction,, can obtain the situation of rocking of vehicle by the signal of photodetector in the two cover measuring systems relatively.

Need to prove, should consider the irregular influence of surface of vehicle during practical application result of a measurement.Can adopt a plurality of laser spots, and utilize them in locational correlativity with use the digital signal processing means to be eliminated or reduce the irregular influence of surface of vehicle result of a measurement.

The invention has the advantages that: measurement is entirely contactless, and the failure rate of machinery of measuring system is low, the survey precision height, and installation and maintenance are convenient; Can composite measurement the crawling of vehicle, rock, athletic posture such as vibration, and the kinematic velocity of train is unrestricted when measuring.

The method of Fig. 1 laser measurement moving attitude of vehicle structural representation of measuring system

The A of Fig. 2 measuring system is to scheme drawing

Fig. 3 uses the Laser Doppler Velocimeter measuring vehicle vibration scheme drawing that crawls

The embodiment that Fig. 4 measuring vehicle is rocked, crawled

Among the figure: 1 is laser emission element, and 2 are the laser pick-off unit, and 3 is signal processing unit, and 4 is laser, 5 is collimator objective, and 6 is lens, and 7 is that photodetector, 8 is spud pile, and 9 is vehicle, 10 is rail, and 11 is ground, and 12,13 is cabinet, and 14 is the making glass plate.

Method of measurement of the present invention: the laser that sends from ground laser emission element 1 is got to the surface of tested moving vehicle 9, by detecting from vehicle 9 surface scatterings to return and reach the laser beam position of laser pick-off unit, ground 2 or the variation of frequency, when obtaining vehicle movement by signal processing unit 3, on the vehicle one or more in the displacement or the velocity variations situation of three directions, thereby obtain the athletic posture of vehicle.

The used measuring system of the inventive method is made up of laser emission element 1, laser pick-off unit 2 and signal processing unit 3.

Fig. 1 and Fig. 2 are a kind of structural representation of measuring system.Described laser emission element 1 is by laser 4, collimator objective 5 is formed, laser 4 and the image requirement arrangement of collimator objective 5 by optical system, and be fixed to together in the cabinet 12 are fixed to cabinet 12 on the spud pile 8 on the ground 11 by bolt or other connection mode; Described laser pick-off unit 2 is made up of lens 6, photodetector 7, lens 6 are arranged by the image requirement of optical system with photodetector 7, and be fixed to together in the cabinet 13, by bolt or other connection mode cabinet 13 is fixed on the spud pile 8 on the ground.The light of laser 4 emission gathers the surface of tested vehicle 9 by object lens 5, and the light scioptics 6 of returning from tested vehicle 9 surface scatterings converge on the photodetector 7.3 pairs of photodetectors of described signal processing unit obtain signal and handle, its position or velocity variations when obtaining vehicle 9 by measurement point, thus obtain the athletic posture of vehicle 9.

When with Fig. 1, when 2 described embodiment come crawling of measuring vehicle, described photodetector 7 is PSD or CCD photodetector.When certain joint vehicle 9 reaches laser measurement point a, ideally, the displacement that vehicle 9 needs only along the rail direction, the position of the light that scattering is returned on photoelectric position detector 7 can not change.Otherwise, vehicle 9 crawls if existing, be that vehicle 9 laterally exists motion, the position that the light that scattering this moment is returned reaches photoelectric position detector 7 can change, by detecting the variation of this position, just can obtain the cross motion of vehicle, thereby obtain the hunting situation of vehicle 9, concrete computing formula is as follows: $V\_=\frac{S\left(t_2\right)-S\left(t_1\right)}{t_2-t_1}----\left(1\right)$ $a\_=\frac{\∂V\_}{\∂t}----\left(2\right)$

In the formula: V_ is the cross velocity of hunting, transverse acceleration when a_ is vehicle 9 motions, S (t ₁), S (t ₂) be respectively t ₁, t ₂The lateral direction of car displacement that moment photodetector 7 records, t ₁, t ₂Be the time.

When using Fig. 1,2 described embodiment come the vibration of measuring vehicle vertical direction, its method of measurement is identical with the method that principle and above-mentioned measuring vehicle are crawled, different is the installation site of measuring system, only need this moment laser emission element 1 and laser pick-off unit 2 are installed between the two rails by two spud piles 8, the luminous point that laser is sent is got to the bottom c point of vehicle 9, by detecting in very short a period of time variation from light position on photoelectric position detector 7 that vehicle bottom diverse location two point scattering are returned, just can obtain the situation of vehicle up-down vibration, concrete computing formula is: $V_{|}=\frac{h\left(t_2\right)-h\left(t_1\right)}{t_2-t_1}----\left(3\right)$ $a_{|}=\frac{\∂V_{|}}{\∂t}----\left(4\right)$

In the formula: V _|Be the vertical speed of hunting, a _|Normal acceleration during for vehicle 9 motions, h (t ₁), h (t ₂) be respectively t ₁, t ₂The vehicle vertical displacement amount that moment photodetector records.

When measuring vehicle 9 is rocked, need to install two cover measuring systems or send two bundle laser simultaneously by a laser emission element, make that the line of two laser spots a, b of outgoing is parallel with the compartment vertical direction, overlap the signal of photodetector in the measuring systems or the signal that two photodetectors in the laser pick-off unit 2 are overlapped in comparison one by comparing two, can obtain the situation of rocking of vehicle, concrete computing formula is: $\mathrm{\θ}\left(t\right)=\frac{[(S_b\left(t_2\right)-S_a\left(t_2\right))-(S_b\left(t_1\right)-S_a\left(t_1\right))]}{D}----\left(5\right)$

In the formula: certain obtains rocking the angle, S to θ (t) constantly for vehicle 9 _b(t ₂), S _a(t ₂) be respectively t ₂The cross travel amount that b point and a are ordered on the vehicle 9 that moment photodetector records, S _b(t ₁), S _a(t ₁) be respectively t ₁The cross travel amount that b point and a are ordered on the vehicle 9 that moment photodetector records.

In like manner can obtain cireular frequency and angular acceleration that vehicle rocks.

The embodiment that directly uses 9 vibrations of Laser Doppler Velocimeter measuring vehicle and crawl as shown in Figure 3.This moment, laser emission element 1 be the laser-Doppler emitting head, and (in fact, in Laser Doppler Velocimeter, launch and accept two parts and usually do and be in the same place, formation is a part of) partly formed by lens 6, photodetector 7 etc. in laser pick-off unit 2.Laser beam emitting head can send multiple laser simultaneously, and reach on the surface of vehicle 9, during vehicle 9 motions, speed causes scattering to return to reach the variation of a plurality of corresponding photodetectors and the frequency of three corresponding detectors of sense of motion vertically, laterally and longitudinally, can directly measure speed, vertical shake and the hunting of vehicle thus.

Measuring vehicle is crawled when rocking, and can adopt more reasonable and simple measuring system shown in Figure 4.Laser emission element 1 is by laser 4, and collimator objective 5, making glass plate 14 constitutes, and this moment, laser emission element 1 emitted laser was a simple pattern (as a spider) after by making glass plate 14, and laser pick-off unit 2 is the CCD camera.The spider of laser beam emitting head emission reaches on the surface of vehicle 9, and vehicle 9 spider images are taken by the CCD camera.Can obtain the speed of laterally crawling and the acceleration/accel of vehicle by formula (1) and (2) according to the variation of position on CCD, spider center; According to the relative displacement variable quantity on spider perpendicular line direction two summits, obtain the situation of rocking of vehicle 9 by formula (5); Similar unique relatively variable quantity according to spider horizon direction two summits obtains the situation of reversing of vehicle 9, in addition by eliminating the influence of surface of vehicle fitfull to the processing of spider distortion situation.

The present invention is suitable for existing all types rail vehicle is detected, and adapts to train speed scope 0～360Km/h.

Directly laser emission element 1 is done with laser pick-off unit 2 on the structure and be in the same place, form an integral body, do not change the function of measuring system; Laser emission element can adopt simple laser transimitter or laser-Doppler emitting head, mainly see which kind of motion of measuring vehicle, in general, simple laser transimitter, simple in structure, cost is low, but survey precision and adaptation car speed are lower, adopting the advantage of laser doppler emitting head is the speed component that can obtain three directions of vehicle simultaneously, but measures the cost height; There are different fixed forms or fixed position in the laser transimitter unit with the laser pick-off unit.

Claims (2)

1. the method for a laser measurement moving attitude of vehicle, it is characterized in that: the laser that sends from ground laser emission element (1) is got to the surface of tested moving vehicle (9), by detecting from vehicle (9) surface scattering to return and reach the laser beam position of laser pick-off unit, ground (2) or the variation of frequency, by signal processing unit (3) when obtaining vehicle movement, on the vehicle one or more in the displacement or the velocity variations situation of three directions, thereby obtain the athletic posture of vehicle.

2. according to the method for the laser measurement moving attitude of vehicle of stating of claim 1, it is characterized in that laser emission element (1) can adopt the laser-Doppler emitting head or have the common laser projector of mark.

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