Coordinate measurement method for optoelectronic scanning measurement system based on response pattern

Abstract

The application discloses a photoelectric scanning measurement system coordinate measurement method based on a response mode, which comprises the following steps: a response type transmitting station transmits a synchronous signal to a processor through a wire at the start of each measurement period, and records the transmission time; the response type transmitting station emits scanning laser to a measurement space, scanning light is captured by a relay response unit, the relay response unit processes the scanning light signal and emits response laser to the space, and the receiving time t of the response laser is recorded by the transmitting station pi ; a response type transmitting station geometric measurement model is constructed, the rotation angle of a scanning light plane is obtained from the transmission time, the receiving time and the transmitting station parameters, and then the coordinates of a point in the space are solved. The application acquires accurate measurement scanning light arrival time, breaks through the problem that the measurement distance is limited in the traditional measurement mechanism, has good feasibility, flexible construction and low cost, and can realize effective growth of the working distance of a measurement system.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of large-scale space high-precision three-dimensional measurement, and in particular to a measurement method of a large-scale space photoelectric scanning measurement system based on a response mode. BACKGROUND

[0002] In the field of industrial manufacturing, high-precision measurement technology, as the core detection link of quality control of cutting-edge manufacturing, has an increasingly important influence on the development of industrial manufacturing. Among them, high-precision large-scale space measurement has become a necessary technology for large-scale precision manufacturing and assembly. Taking aerospace manufacturing as the main representative, the size to be measured in such industrial manufacturing sites is large, and most of them are assembled by segmented processing. During the docking and assembly process, the spatial coordinates and poses of each part need to be controlled in real time to provide protection for the quality of the final assembly product. Large-scale space precision measurement has become an important technology in the intelligent manufacturing and assembly process of large-scale equipment such as aerospace. The large-scale space photoelectric scanning measurement system is a new type of three-dimensional coordinate measurement system based on photoelectric scanning. With the help of multiple transmitting stations networking to build a large measurement field, combined with several photoelectric receivers to realize parallel multi-task measurement. The measurement system has high static precision, and compared with the traditional single-station serial single-task measurement method, the measurement efficiency is greatly improved.

[0003] With the development of modern industry, the size of industrial products is getting larger and larger, and accordingly, the measurement range of the measuring instrument also needs to be expanded. In the face of a huge measurement scene, equipment with a short measurement distance needs to build a field multiple times and move the measurement equipment, which greatly affects the efficiency and accuracy of measurement. Therefore, increasing the working distance of the measuring instrument is the best solution. SUMMARY

[0004] The present application provides a photoelectric scanning measurement system measurement method based on a response mode. The present application aims to solve the problem of insufficient measurement distance of the photoelectric scanning measurement system in large-scale space, and provides a new measurement mechanism. The accurate measurement scanning light arrival time is obtained, which breaks through the problem of limited measurement distance of the traditional measurement mechanism, has good feasibility, flexible construction, low cost, and can effectively increase the working distance of the measurement system. Details are described below:

[0005] A measurement method of a large-scale space photoelectric scanning measurement system based on a response mode, the method comprising:

[0006] 1) The response type transmitting station transmits a synchronization signal to the processor through a wire at the beginning of each measurement period, and records the transmission time as t po ;

[0007] 2) the response station transmits scanning laser to the measuring space, the scanning light is captured by the relay response unit, the relay response unit processes the scanning light signal and transmits response laser to the space, and the receiving time t of the response laser is recorded by the transmitting station pi ;

[0008] 3) the geometric measurement model of the response station is constructed, the rotation angle of the scanning light plane is obtained from the transmission time t po , the receiving time t pi and the parameters of the transmitting station, and then the coordinates of the point in the space are solved.

[0009] The method further comprises: finding two pairs of scanning light signals with the smallest phase change in adjacent two periods as the two scanning light signals of the station in the period, and specifically comprising:

[0010] 1) calculating the time difference between the light signal receiving time t pi of the current period and the time t p0 ;

[0011] 2) storing in the queue;

[0012] 3) comparing the time difference of the last period in the queue;

[0013] 4) analogizing the last period, the time difference between the time t p0 -T and the time t p0 of the previous period;

[0014] 5) calculating the difference value of the corresponding time difference in adjacent two queues and sorting the size;

[0015] 6) obtaining the minimum result between two groups as the data of the adjacent two periods of a station.

[0016] Further, the relay response unit comprises:

[0017] In the design of the response signal, the coding signal is added, after the rising edge detection laser signal and the lighting of the response laser, a period of time is delayed, the laser tube is lighted according to the coding rule, and the laser tube is lighted as the mark for distinguishing different relay response units;

[0018] According to the pulse sequence, each light tube is triggered in turn, the duty cycle of a single light tube is reduced, and the emission of the response pulse laser of the transmitting station in the measuring range is realized.

[0019] The technical scheme provided by the application has the beneficial effects that:

[0020] 1. The application improves the defects of the original light recognition mode in long distance measurement. The scanning light and the synchronous light of the original photoelectric scanning measurement system exist in a physical space at the same time, but the increase of the distance leads to the gradual approach of the scanning light and the synchronous light pulse width. The pulse width recognition method cannot distinguish the type of the light plane in the long distance measurement field, resulting in the failure of spatial positioning.

[0021] 2. The application adopts the design of the response mechanism to realize the separation of the scanning light and the synchronous light in space. As long as the light intensity is within the allowable range, the measurement range can be infinitely extended.

[0022] 3. The application simplifies the wired connection between the original receiving ball and the processor, greatly improving the convenience of measurement.

[0023] 4. The application designs the receiving device as a response type structure, which identifies the light emitted by the receiving transmitting station, and then uses the relay response unit to perform response operation. The original transmitting station increases the receiving response signal function and transmits the synchronous signal to the processor for unified processing and settlement.

[0024] 5. The application can realize accurate measurement of large size space geometric quantity without cooperating with external geometric quantity measurement equipment under large scale environmental conditions, and solve the problem of short photoelectric scanning measurement distance in the existing large scale space. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The application is a response principle mechanism of the response type photoelectric scanning measurement positioning system.

[0026] Figure 2 The application is a schematic diagram of the response signal and the scanning light signal of the response type photoelectric scanning measurement positioning system.

[0027] Among them, Figure 2 (upper) is the scanning light signal received by the response type relay receiver; Figure 2 (lower) is the response light signal emitted by the response type relay receiver.

[0028] Figure 3 The application is a schematic diagram of each signal in the response signal of the response type photoelectric scanning measurement system and its meaning.

[0029] Figure 4 The application is a schematic diagram of the overall tooling of the relay response unit.

[0030] Figure 5 The application is a schematic diagram of the response type transmitting station. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the application clearer, the embodiments of the application are described in detail below.

[0032] The measurement process of the method is as shown in the following (as shown in Figure 1 ) :

[0033] 101: Establish a multi-station measurement field, set different rotating speeds for the multi-stations, calibrate the measurement field by using a reference ruler, and obtain the positional relationship between the stations;

[0034] 102: The rotating head of the response type transmitting station rotates at a constant speed. In a rotating period, the transmitting station transmits a synchronization signal to the processor through a wire at the zero point position of the rotating table, and records it as t po .

[0035] 103: Place a relay response unit at the point to be measured, and make the light pipe face the response type transmitting station. The relay receiver receives the light signal from the first scanning light plane 1, and emits a very short pulsed laser at the rising edge and the falling edge, respectively, which is received by the receiving ball on the transmitting station, and the time is recorded as t p11 and t p12 ; correspondingly, the time corresponding to the second scanning light plane 2 is t p21 and t p22 . Among them, the receiving ball on the transmitting station receives the response light signal to the processor, and records the time when the scanning light arrives as the middle value of the rising edge time and the falling edge time. Therefore, the time when the first scanning light plane 1 arrives at the relay response unit is:

[0036]

[0037] Similarly, the arrival time of the second scanning light plane 2 is:

[0038]

[0039] 104: Obtain the rotation angle of the scanning light plane from t po , t pi and the parameters of the transmitting station.

[0040] When the two laser fans respectively sweep the receiver, the time when the synchronization light signal, the light signals of the first and second scanning light planes arrive at the receiving ball are t po , t p1 and t p2 , respectively. The rotation angles of the first and second scanning light planes are:

[0041]

[0042] Among them, ω is the rotating speed of the transmitting station.

[0043] 105: Construct a geometric measurement model of the response type transmitting station, and then solve to obtain specific coordinates;

[0044] The sector relationship of the emitting station and the geometric model of a light plane can be obtained according to the geometric relationship as follows:

[0045]

[0046] wherein, α is the included angle between the first scanning light plane 1 and the rotation axis; β is the included angle between the second scanning light plane 2 and the rotation axis; γ is the vertical angle of the point to be measured relative to the original point of the emitting station; θ is the horizontal angle of the point to be measured relative to the original point of the emitting station. θ1 is the rotation angle of the first scanning light plane 1; θ2 is the rotation angle of the second scanning light plane 2; a is the horizontal angle of the point to be measured relative to the original point of the emitting station. off

[0047] A right-hand coordinate system of the emitting station is established, and the intersection of the first scanning light plane 1 and the rotation axis is defined as the original point, the rotation axis is defined as the Z axis, and the straight line on the first scanning light plane 1 passing through the original point and being perpendicular to the rotation axis is defined as the X axis.

[0048] wherein, the equations of the first and second scanning light planes at the initial position are respectively:

[0049]

[0050] At this time, the equation parameters of the light plane equations of the two rotating lasers of the emitting station in the local coordinate system are as follows:

[0051]

[0052] wherein, a is the plane parameter a of the light plane (1 or 2) at a certain moment; b is the plane parameter b of the light plane (1 or 2) at a certain moment; c is the plane parameter c of the light plane (1 or 2) at a certain moment; d is the plane parameter d of the light plane (1 or 2) at a certain moment; a is the plane parameter a of the light plane (1 or 2) before rotation; b is the plane parameter b of the light plane (1 or 2) before rotation; c is the plane parameter c of the light plane (1 or 2) before rotation; d is the plane parameter d of the light plane (1 or 2) before rotation; θ is the rotation angle corresponding from the initial moment to a certain moment after rotation. i i i i m m m m m

[0053]

[0054] The matrix [Ri, Ti] is used to realize the transformation of the local coordinate system of the i th emitting station into the global coordinate system, wherein R is the rotation matrix of the i th emitting station, and T is the translation matrix of the i th emitting station.​​​​​​​​​​​i is a rotation matrix, T i is a translation matrix, then in each local coordinate system, each transmitting station has:

[0055]

[0056] i = 1, 2, 3, and j = 1, 2 (9)

[0057] Wherein: i is the transmitting station number; j is the laser fan number; [x k y k z k ] T represents the coordinates of the point to be solved in the global coordinate system; R i and T i represent the conversion relationship from the global coordinate system to the transmitting station i; a ij b ij c ij d ij all represent the parameters of the j plane of the transmitting station i. Using the above relationship, in order to solve the specific spatial coordinates, two transmitting stations are built to realize accurate positioning.

[0058] Wherein, the relay response receiving module comprises: a photoelectric receiving device, an FPGA processing core, and a bottom circuit board as a signal transceiver and a laser light pipe. The configured battery supplies power to the FPGA and the laser tube through the bottom board. The entire relay response receiving module is packaged in a designed aluminum tool (as shown in Figure 4 ).

[0059] The embodiment of the application is redesigned on the basis of the original transmitting station, so that when the synchronous light passes through the code disc zero point, the original synchronous light signal is changed to an electrical signal which is led out through a lead, and one synchronous signal is output in one rotation period. The signal is input to the input pin of the FPGA in the processor (as shown in Figure 5 ).

[0060] For each transmitting station, the synchronization signal of the station is given by its own code disc. If the synchronization signal is used as the starting point of the measurement time, the response signal generated by the scanning unit of the non-transmitting station cannot be kept stable in phase (i.e. T1T2) on the time axis. A new identification mode is designed: find the two pairs of scanning light signals with the smallest phase change in the adjacent two periods, which can be considered as the two scanning light signals of the station in the period, and the phase 1 and the phase 2 are the values of T1 and T2.

[0061] Wherein, the algorithm identification process realized in the substation process is:

[0062] 1) Calculate the light signal receiving time t pi (i = 1, 2) and the timing starting point t p0The time difference (T1 and T2) of the two time points;

[0063] 2) store in the queue;

[0064] 3) compare the time difference of the last period in the queue (the starting point of the time is t p0 -T);

[0065] 4) analogize the time difference of the last period (the starting point of the time is t p0 -T) and the last period (the starting point of the time is t p0 -2*T);

[0066] 5) calculate the difference of the corresponding time difference in the adjacent two queues and sort the size;

[0067] 6) get the minimum result between the two groups as the data of the adjacent two periods of a station.

[0068] The embodiment of the application adds a repeater response unit on the basis of the structure of the original system, and has the following innovations:

[0069] S1) Change the original design of the receiver of the system only receiving optical signals without response, and reply the response light to the transmitting station after receiving the scanning light;

[0070] S2) The response type transmitting station does not transmit the synchronous optical signal to the whole measurement field through the light pipe, but is led out in the form of signal line and enters the processor as the starting point of time of each rotation period;

[0071] S3) After the repeater response unit receives the optical signal, the pulsed laser is lit at the rising edge and the falling edge of the scanning light, and the lighting duration is one clock cycle;

[0072] S4) In order to realize the differentiation of the response signals of different response type receivers, coding signals are added in the design of the response signals, after detecting the laser signal at the rising edge and lighting the response laser, a period of time is delayed, and the laser tube is lit according to the coding rule as a mark for distinguishing different repeater response units (such as shown in Figure 3 );

[0073] S5) Design a new driving method for the response laser: in order to solve the problem of insufficient charging of the light pipe caused by multiple lighting of the laser tube in a very short time. The embodiment of the application triggers each light pipe in turn according to the pulse sequence, reduces the duty cycle of a single light pipe, and realizes the accurate emission of the response pulsed laser of the transmitting station in the measurement range.

[0074] S6) Design signal recognition and processing program, realize the substation identification to the synchronization signal output from the transmitting station and the reply optical signal returned by the reply type relay unit, for each transmitting station, take the station synchronization signal as the measurement time starting point, then the relay reply signal generated by the non-transmitting station scanning light cannot realize the phase (namely T1, T2) stability on the time axis. Through this program design, the correspondence of the synchronization light and the numerous reply lights is realized, so as to calculate the subsequent coordinates.

[0075] The model of each device in the embodiments of the present application is not limited unless otherwise specified, and any device that can complete the above functions can be used.

[0076] Those skilled in the art can understand that the drawings are only schematic diagrams of a preferred embodiment, and the above-mentioned serial numbers of the embodiments of the present application are only for description, not representing the advantages and disadvantages of the embodiments.

[0077] The above is only the preferred embodiment of the present application, and does not limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A measurement method for a large-scale spatial photoelectric scanning measurement system based on response modes, characterized in that, The method includes: At the beginning of each measurement cycle, the transponder station transmits a synchronization signal to the processor via a wire, and records the transmission time as t. po ; A relay response unit is placed at the point to be measured, with the LED facing the responsive transmitter station. The relay receiver receives the optical signal from the first scanning light plane and emits a very brief pulse laser at both the rising and falling edges, which is received by the receiving ball on the transmitter station. The recording time is t. p11 and t p12 The time corresponding to the second scanning light plane is t. p21 and t p22 The arrival time of the first scanning light plane at the relay response unit is: ； The arrival time of the second scanning light plane is: ； By t po ,t pi The rotation angle of the scanning light plane is obtained from the parameters of the transmitting station; When the two laser sectors sweep across the receiver, the times when the synchronization optical signal and the optical signals from the first and second scanning optical planes arrive at the receiving sphere are respectively: t po and t p1 and t p2 The rotation angles of the first and second scanning light planes are obtained as follows: ； Where w is the rotational speed of the launch station; A geometric measurement model of the responding transmitter station is constructed, and its specific coordinates are calculated. The sector relationship of the transmitter station and the geometric model of a certain light plane are obtained based on the geometric relationships. ； in, The angle between the first scanning light plane and the rotation axis; The angle between the second scanning light plane and the rotation axis; The vertical angle between the point to be measured and the origin of the transmitting station; The horizontal angular deviation of the center positions of the two lasers relative to the direction of rotation axis; The rotation angle of the first scanning light plane; The rotation angle of the second scanning light plane; The horizontal angle of the point to be measured relative to the origin of the transmitting station; Establish a right-handed coordinate system for the launch station, define the intersection of the first scanning light plane and the rotation axis as the origin, the rotation axis as the Z-axis, and the straight line on the first scanning light plane that passes through the origin and is perpendicular to the rotation axis as the X-axis; The equations for the first and second scanning light planes at their initial positions are as follows: ； At this point, the equation parameters of the optical plane equations of the two rotating lasers at the transmitting station in their own coordinate system are: ； in, Let a be the plane parameter of the light plane at a certain moment. Let b be the plane parameter of the light plane at a certain moment. Let c be the plane parameter of the light plane at a certain moment. Let d be the plane parameter of the light plane at a certain moment. Let a be the plane parameter before the light plane is rotated. Let b be the plane parameter before the light plane is rotated. Let c be the plane parameter before the light plane is rotated. Let d be the plane parameter before the light plane is rotated. This represents the rotation angle from the initial moment to a certain moment after the rotation; ； The transformation between the local and global coordinate systems of the i-th launching station is achieved using the matrix [Ri, Ti]. For rotation matrix, As the translation matrix, then in each local coordinate system, for each launching station: ； i = 1, 2, 3, ..., j = 1, 2; Where: i is the transmitting station number; j is the laser sector number; This represents the coordinates of the point to be determined in the global coordinate system; All of these represent parameters of the j-plane of launch station i. Using the above relationship, two launch stations are built to achieve precise positioning in order to calculate the specific spatial coordinates.

2. The measurement method of a large-scale spatial photoelectric scanning measurement system based on response mode according to claim 1, characterized in that, The method further includes: identifying the two pairs of scanning optical signals with the smallest phase change within two adjacent cycles, and using them as the two scanning optical signals for that station in that cycle, specifically: 1) Calculate the optical signal reception time for this cycle. and the starting point of the timekeeping Time difference; 2) Store in a queue; 3) Compare the time difference of the previous period in the queue; 4) Following the same pattern as the previous cycle, the starting point for timing is... -T and its preceding cycle, the timing start point is -2*T time difference; 5) Calculate the time difference between corresponding pairs of adjacent queues and sort them by size; 6) The result between the two sets with the smallest difference is taken as the data for two adjacent cycles of a station.

3. The measurement method of a large-scale spatial photoelectric scanning measurement system based on response mode according to claim 1, characterized in that, The relay response unit is: An coded signal is incorporated into the design of the response signal. After detecting the laser signal and lighting the response laser on the rising edge, there is a delay before the laser tube is lit according to the coding rule, which serves as a marker to distinguish different relay response units. Each optical tube is triggered sequentially according to the pulse sequence, reducing the duty cycle of a single optical tube to achieve the emission of response pulse laser from the transmitting station within the measurement range.

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