CN103528520A - Binocular vision-based synchronous operation lifting system detection system and method - Google Patents

Abstract

The invention relates to a binocular vision-based synchronous operation lifting system detection system and a method. The system comprises a synchronous operation lifting system, two CCD (Charge Coupled Device) cameras, bases of the CCD cameras, a plurality of artificial target points, two auxiliary light sources and a computer, the two CCD cameras are mounted over the synchronous operation lifting system, the artificial target points are respectively mounted at different positions on the synchronous operation lifting system, and the two CCD cameras can continuously acquire and transmit the images of the artificial target points to the computer. The method includes the following steps: a coordinate system is established, the two cameras respectively acquire and transmit a digital image of the artificial target points to the computer, the image information of the two cameras are integrated, the binocular vision imaging theory is utilized to calculate the three-dimensional coordinates of each artificial target point under the world coordinate system, and linear operation is then utilized to work out the synchronism and verticality error of each lifting axis of the synchronous operation lifting system. The non-contact, disturbance-less and high-frequency measurement of the synchronous operation lifting system is realized.

Description

Pick-up unit and the method for the synchronous operation jack-up system based on binocular vision

Technical field

The present invention relates to measuring technique, be specifically related to a kind of pick-up unit and method of the synchronous operation jack-up system based on binocular vision.

Background technology

Three-axis air-bearing table system is the key equipment of satellite ground emulation testing; wherein synchronous operation jack-up system is the important component part of three-axis air-bearing table system; conventionally by many lifting jack, form multi-axial Simultaneous operation jack-up system, be responsible for the functions such as auxiliary dismounting, location and protection of ball bearing and instrument platform.Because the requirements such as Satellite Experiment is highly reliable to equipment proposition, high precision, the synchronism error of multi-axial Simultaneous operation jack-up system, the error of perpendicularity etc. are two key technical index wherein, due to the singularity of three-axis air-bearing table system on building, it is puzzlement technician's a difficult problem that the synchronism of its synchronous jacking system, verticality detect always.

In order to measure the synchronism of a plurality of jacking axles, the early stage method adopting is to use slide calliper rule manually to detect the displacement of each jacking axle, or utilizes the components and parts conjunction measurings such as buting iron, travel switch, optoelectronic switch.In order to improve precision and automaticity, mainly use tangent displacement sensor (as increment or absolute magnitude stay-supported type displacement sensor) at present.

Through searching document, find, Chinese invention patent application number: 201110249263.2, patent name is: test bench for loading synchronous jacking device, this Patent design a kind of testing table while being used for testing the synchronization accuracy of synchronous jacking device, need in use device being tested to be carried on this testing table, then use displacement transducer to detect the synchronization accuracy of synchronous jacking device.Due to self ad hoc structure and weight of synchronous operation jack-up system, be not suitable for using this metering system to measure.

Chinese invention patent application number: 200610019913.3, patent name is: multipoint synchronous lifting device and elevating method thereof, this patent adopts Programmable Logic Controller and variable-frequency control technique synchro control hydraulic lift, and displacement data is provided by the absolute type displacement transducer of independently installing.

At document " gate synchronous jacking system ", (be published in Chinese core journals " Central China University of Science and Technology's journal " (natural science edition) the 36th the 6th phase of volume in 2008,7-9), the synchronous jacking system that a plurality of lifting jack synchronization actions are realized gate jacking is controlled in the introductions such as Chen Baijin.In this system, on each lifting jack, install displacement transducer additional, realize the displacement detecting to jacking axle.

Adopt displacement transducer to detect synchronous shift, mainly contain following shortcoming: one, belong to the metering system of contact, disturb the motion of tested moving component, be unfavorable for Measurement accuracy; Two, displacement transducer can only detect displacement, can not detect the error of perpendicularity of each jacking axle; Three, displacement transducer itself has certain nonlinearity erron, in document " demarcation of hydraulic synchronization lifting control system sensor error " (" observation and control technology " the 32nd the 1st phase of volume in 2013,11-13), Lu Kingdom's virtue waits the linearity problems of pointing out displacement transducer self, in use procedure, between measured value and actual value, there is at the scene certain error, must carry out on-line proving to displacement transducer.

So the measurement of the synchronous operation jack-up system that the inapplicable three-axis air-bearing table of above metering system is used, need to consider new measuring method and device.

Summary of the invention

Based on above weak point, the object of the present invention is to provide a kind of pick-up unit and method of the synchronous operation jack-up system based on binocular vision, synchronism and the vertical error of each jacking axle in jacking process in can kinetic measurement synchronous operation jack-up system, and can synchronous jacking system not produced and be disturbed.

The technology used in the present invention is as follows: a kind of synchronous operation jack-up system multi-axial Simultaneous operation binocular vision measurement mechanism, adopt synchronous operation jack-up system, this device also comprises two black and white digital CCD video cameras and pedestal thereof, a plurality of artificial targets, two secondary light sources and computing machine, two black and white digital CCD video cameras are installed above synchronous operation jack-up system, black and white digital CCD video camera is arranged on pedestal, two black and white digital CCD camera parameters are identical, and their imaging surface is in the same plane, optical axis is parallel, photocentre is located along the same line, each black and white digital CCD video camera is attached with a secondary light source, a plurality of artificial targets are divided into two groups, on the pedestal table top that a group is arranged on jack-up system, this group artificial target is more than or equal to three, another group is arranged on the surface of each jacking axle of jack-up system, black and white digital CCD video camera is connected with converter by data line, converter is connected with computing machine, and the camera lens of black and white digital CCD video camera is object space telecentric lens, two black and white digital CCD video camera continuous acquisition artificial targets' image is also transferred to computing machine, and computing machine is analyzed image information and process.

The present invention also has following feature:

A kind of synchronous operation jack-up system multi-axial Simultaneous operation binocular vision measuring method that adopts a kind of synchronous operation jack-up system multi-axial Simultaneous operation binocular vision measurement mechanism as above to draw is as follows:

(1), be arranged on the artificial target on pedestal table top, for setting up the pedestal of synchronous operation jack-up system at the plane equation of world coordinate system; Be arranged on the lip-deep artificial target of each jacking axle, be used for measuring the moving displacement of each jacking axle, set related world coordinate system and overlap with the imaging surface coordinate system of a black and white digital CCD video camera;

(2), two black and white digital CCD video cameras gather in real time, continuously artificial target's image, and transfer to computing machine;

(3), computing machine carries out respectively feature extraction to the two width images from two black and white digital CCD video cameras, utilizes sub-pixel positioning method to determine artificial target's coordinate in two width images respectively;

(4), utilize binocular vision image-forming principle, calculate the coordinate of each artificial target in world coordinate system;

(5), utilize linear algebra principle, set up the plane equation of pedestal table top in world coordinate system;

(6), for the positional information of artificial target in world coordinate system on the plane equation of pedestal table top and the surface of each jacking axle, utilize linear algebra principle, calculate the moving displacement data of the relative pedestal table top of each jacking axle;

(7), according to the positional information of each artificial target in world coordinate system on jacking axle, according to calculate decomposing, obtain synchronous operation jack-up system each axle operation synchro measure error and error of perpendicularity.

The basic functional principle of this device is:

Two video cameras gather the digital picture of synchronous operation jack-up system simultaneously and are transferred to computing machine to be analyzed and processes, and computing machine completes the processing of feature extraction, sub-pixel positioning for these monumented points.Utilize the locating information of monumented point, according to binocular vision image-forming principle, calculate each artificial target's volume coordinate information.For these information, apply the linear theory of computation can calculate each artificial target between geometric relationship, and then calculate synchronous error and the error of perpendicularity.Realize in this way noncontact, undisturbed, high-frequency measurement to the multi-axial Simultaneous jacking process of synchronous operation jack-up system.

The synchronous operation jack-up system measurement mechanism that the present invention proposes and concrete measuring method, have the following advantages:

(1), the present invention adopts non-contact vision to measure, synchronous operation measuring process can not produce and disturb the motion of each jacking axle of jack-up system;

(2), vision measurement technology involved in the present invention, can detect the synchronous running accuracy of each jacking axle of synchronous operation jack-up system;

(3), vision measurement technology involved in the present invention, can detect the error of perpendicularity of each jacking axle of synchronous operation jack-up system;

(4), the present invention adopts black and white digital camera to computing machine, to transmit data by converter, and the electromagnetic environment of synchronous jacking system work is had to antijamming capability;

(5), vision measurement technology involved in the present invention, do not need to carry out online error calibration, computation process is succinct, precision is high, speed is fast.

Accompanying drawing explanation

Fig. 1 is that synchronous operation jack-up system multi-axial Simultaneous jacking measurement mechanism forms front view;

Fig. 2 is synchronous operation jack-up system vertical view;

Fig. 3 is binocular vision imaging schematic diagram;

Fig. 4 is binocular vision 3 D measurement of coordinates schematic diagram;

Fig. 5 is synchronous operation jack-up system base plane equation schematic diagram calculation;

Fig. 6 is synchronous operation jack-up system jacking axle moving displacement measuring principle figure;

Fig. 7 is synchronous operation jack-up system multi-axial Simultaneous jacking measurement procedure figure;

Fig. 8 is image processing module process flow diagram.

Embodiment

Below in conjunction with accompanying drawing, the invention will be further described for example.

Embodiment 1

Referring to Fig. 1, from apparatus of the present invention, mainly by following part, formed: the first black and white digital CCD video camera 101, the second black and white digital CCD video camera 103, the first camera lens 102, the second camera lens 104, the first video camera pedestal 105, the second video camera pedestal 106, the first artificial light source 201, the second artificial light source 202, pedestal table top 301, jacking axle 302, motor and drive unit 303, base 304, artificial target 305, artificial target 306, converter 4, computing machine 5 and switch board 6.Two black and white digital CCD video cameras 101.103 are arranged on respectively on the first and second video camera pedestals 105.106, two black and white digital CCD camera parameters are identical, and their imaging surface is in the same plane, optical axis is parallel, photocentre is located along the same line, and each black and white digital CCD video camera is attached with an artificial light source; A plurality of artificial targets are arranged on respectively on the diverse location of synchronous jacking system, and black and white digital CCD video camera is connected with converter by data line, and converter is connected with computing machine, anti-interference, and the camera lens of black and white digital CCD video camera is object space telecentric lens; Two black and white digital CCD video camera continuous acquisition artificial targets' image is also transferred to computing machine, and computing machine is analyzed image information and process.

Video camera is selected black and white digital CCD video camera, uses converter 4 to be connected with computing machine 5, anti-interference.

The first camera lens 102 and the second camera lens 104 are object space telecentric lens.

Artificial light source for image acquisition provide constant, reliably illumination.

The present invention utilizes binocular camera collection artificial target's image, utilizes binocular vision measuring principle to measure synchronism and the verticality of each jacking axle of synchronous operation jack-up system, and main flow process diagram intention as shown in Figure 7, mainly comprises following key step:

(1) two camera calibration, determines the inner parameter of video camera;

(2) two video cameras are installed in parallel on video camera pedestal, require camera optical axis parallel, point-blank, in one plane, the air line distance of two photocentres is B to imaging surface to photocentre, as shown in Figure 3;

(3) set related world coordinate system in synchronous operation jack-up system measuring process and overlap with the imaging surface coordinate system of a video camera, in world coordinate system, each artificial monumented point has unique three-dimensional coordinate;

(4) lineup's work monumented point is arranged on pedestal table top, effect is to set up the plane equation of the pedestal table top of synchronous operation jack-up system in world coordinate system;

(5) other artificial target is arranged on the surface of each axle, is used for measuring the moving displacement of each jacking axle;

(6) image processing program carries out respectively feature extraction to the two width images from two video cameras, then utilizes sub-pixel positioning technology to determine artificial target's coordinate in two width images respectively.Related algorithm be illustrated in peak etc. works " precision measurement based on image and motion measurement ”， Science Press publish, in July, 2002 first published; Image processing module flow process is as Fig. 8;

(7) utilize binocular vision image-forming principle, calculate the coordinate of each artificial target in world coordinate system;

(8) utilize linear algebra principle, set up the plane equation of pedestal table top in world coordinate system;

(9) for the positional information of each artificial target in world coordinate system on the plane equation of pedestal table top and axle, utilize linear algebra principle, calculate the moving displacement data of the relative pedestal table top of each jacking axle;

(10), for the result of calculation of step 9, decompose and obtain synchronous operation jack-up system each axle operation synchro measure error and error of perpendicularity;

Embodiment 2

As shown in Figure 3, relate to following coordinate system:

(1) world coordinate system O _wx _wy _wz _w;

Image pixel coordinate system O ' x ' y ' of (2) first black and white digital CCD video camera 101 imaging surfaces;

The image physical coordinates of (3) second black and white digital CCD video camera 103 imaging surfaces is Oxy;

(4) face O _wx _wy _woverlap with face O ' x ' y ', z _waxle and optical axis coincidence.

Synchronous operation jack-up system binocular vision measuring process of the present invention:

1, binocular vision is measured ultimate principle

Binocular vision imaging can obtain the different image of two width of Same Scene, and the system model of binocular imaging can be regarded as and combined by two monocular imaging systems.As shown in Figure 3, the camera coordinates of setting world coordinate system and First video camera overlaps, object point respectively on two video camera imaging faces imaging point be (x ₁, y ₁), (x ₂, y ₂), the distance between the optical center of two video cameras is called the baseline B of binocular vision system, utilizes binocular vision imaging system to determine to have the world coordinate system coordinate of certain object point W in three dimensions.

According to geometrical similarity principle, as Fig. 4, three dimensions W (x _w, y _w, z _w) point is at the x of world coordinate system _waxial coordinate can be expressed as

$\frac{x_1}{-x_w}=\frac{f}{z_w-f}---\left(1\right)$

$\frac{-x_2}{B+x_w}=\frac{f}{z_w-f}---\left(2\right)$

Wherein, f represents image-forming range.By (1), (2) formula, can be solved,

$z_w=f(1-\frac{B}{D})---\left(3\right)$

Wherein, D=x ₂-x ₁.

Object point W is at world coordinate system x _waxle and y _wcoordinate on axle, calculates

$x_w=\frac{x_1}{f}(f-z)---\left(4\right)$

In like manner

$y_w=\frac{y_1}{f}(f-z)---\left(5\right)$

By (3), (4) and (5), the imaging parallax by three dimensions o'clock at two video cameras, can ask 1, space W at world coordinate system O _wx _wy _wz _win three-dimensional coordinate.

2, set up the plane equation of pedestal table top

As shown in Figure 5, in Fig. 1,3 artificial targets 306 on pedestal are expressed as M ₁, M ₂, M ₃, they are at world coordinate system O _wx _wy _wz _win coordinate be respectively (x _{w, 1}, y _{w, 1}, z _{w, 1}), (x _{w, 2}, y _{w, 2}, z _{w, 2}) and (x _{w, 3}, y _{w, 3,}, z _{w, 3}).

Can obtain vector $\stackrel{\→}{M_1{M}_2}=(x_{w,2}-x_{w,1},y_{w,2}-y_{w,1},z_{w,2}-z_{w,1}),$

$\stackrel{\→}{M_1{M}_3}=(x_{w,3}-x_{w,1},y_{w,3}-y_{w,1},z_{w,3}-z_{w,1})$

Vector

with

the plane equation forming is:

a(x _w-x _w，1)+b(y _w-y _w，1)+c(z _w-z _w，1)=0， (6)

Wherein,

a=(u ₂v ₃，-u ₃v ₂)，b=(u ₃v ₁，-u ₁v ₃)，c=(u ₁v ₂，-u ₂v ₁)

u ₁＝x _w，2-x _w，1，u ₂=y _w，2-y _w，1，u ₂=z _w，2-z _w，1 (7)

v ₁=x _w，3-x _w，1，v ₂=y _w，3-y _w，1，v ₂=u ₂=z _w，3-z _w，1

3. the artificial target of each jacking axle and the range observation principle between base plane

Normal line vector by the known base plane of formula (6) is

if Q=is (x ₀, y ₀, z ₀) be any point in base plane, P _i=(x _i, y _i, z _i) be the coordinate of artificial target on i root axle,

for vector

at normal

projection vector in direction, D is P _i=(x _i, y _i, z _i) with the distance of base plane, as

$D=\left|\right|{\mathrm{proj}}_{\stackrel{\→}{n}}^{\stackrel{\→}{\mathrm{QP}}}\left|\right|=\frac{{\stackrel{\→}{\mathrm{QP}}}_i\·\stackrel{\→}{n}}{\left|\right|\stackrel{\→}{n}\left|\right|}=\frac{a(x_i-x_0)+b(y_i-y_0)+c(z_i-z_0)}{\sqrt{a^2+b^2+c^2}}---\left(8\right)$

3, vertical error is measured

If constantly, the artificial target's point coordinate on i root axle is P to k _{i, k}, constantly, this artificial target's point coordinate is P to k-1 _{i, k-1}, when this artificial target is from k-1, be carved into k constantly the movement locus in during this period of time can use vector

represent, i root axle and normal

between angle be

${\mathrm{\θ}}_k={\sin }^{-1}\left(\frac{\stackrel{\→}{P_{i,k}{P}_{i,k-1}}\⊗\stackrel{\→}{n}}{\left|\right|\stackrel{\→}{P_{i,k}{P}_{i,k-1}}\left|\right|}\right)---\left(9\right)$ 。

Claims (2)

1. a synchronous operation jack-up system multi-axial Simultaneous moves binocular vision measurement mechanism, comprise synchronous operation jack-up system, it is characterized in that: also comprise two black and white digital CCD video cameras and pedestal thereof, a plurality of artificial targets, two secondary light sources and computing machine, two black and white digital CCD video cameras are installed above synchronous operation jack-up system, black and white digital CCD video camera is arranged on pedestal, two black and white digital CCD camera parameters are identical, and their imaging surface is in the same plane, optical axis is parallel, photocentre is located along the same line, each black and white digital CCD video camera is attached with a secondary light source, a plurality of artificial targets are divided into two groups, on the pedestal table top that a group is arranged on jack-up system, this group artificial target is more than or equal to three, another group is arranged on the surface of each jacking axle of jack-up system, black and white digital CCD video camera is connected with converter by data line, converter is connected with computing machine, and the camera lens of black and white digital CCD video camera is object space telecentric lens, two black and white digital CCD video camera continuous acquisition artificial targets' image is also transferred to computing machine, and computing machine is analyzed image information and process.

2. a kind of synchronous operation jack-up system multi-axial Simultaneous operation binocular vision measuring method that a kind of synchronous operation jack-up system multi-axial Simultaneous operation binocular vision measurement mechanism according to claim 1 draws, is characterized in that, method is as follows:

(1), be arranged on the artificial target on pedestal table top, for setting up the pedestal of synchronous operation jack-up system at the plane equation of world coordinate system; Be arranged on the lip-deep artificial target of each jacking axle, be used for measuring the moving displacement of each jacking axle, set related world coordinate system and overlap with the imaging surface coordinate system of a black and white digital CCD video camera;

(2), two black and white digital CCD video cameras gather in real time, continuously artificial target's image, and transfer to computing machine;

(3), computing machine carries out respectively feature extraction to the two width images from two black and white digital CCD video cameras, utilizes sub-pixel positioning method to determine artificial target's coordinate in two width images respectively;

(4), utilize binocular vision image-forming principle, calculate the coordinate of each artificial target in world coordinate system;

(5), utilize linear algebra principle, set up the plane equation of pedestal table top in world coordinate system;

(6), for the positional information of artificial target in world coordinate system on the plane equation of pedestal table top and the surface of each jacking axle, utilize linear algebra principle, calculate the moving displacement data of the relative pedestal table top of each jacking axle;

(7), according to the positional information of each artificial target in world coordinate system on jacking axle, according to calculate decomposing, obtain synchronous operation jack-up system each axle operation synchro measure error and error of perpendicularity.

Images