CN113050064A

CN113050064A - Programmable laser scanning track device

Info

Publication number: CN113050064A
Application number: CN202011105448.1A
Authority: CN
Inventors: 周国清; 林港超; 周祥; 李先行; 李伟豪; 谭逸之; 胡皓程
Original assignee: Guilin University of Technology
Current assignee: Guilin University of Technology
Priority date: 2020-10-15
Filing date: 2020-10-15
Publication date: 2021-06-29

Abstract

The invention discloses a device for programmable laser scanning track, which can program the scanning track of laser radar. The unit includes three front surface mirrors, three mirror brackets, two integrated stepper motors, two motor-fixing brackets, and a base. Its characteristics are: using the front reflector's wide coverage of the reflection band, high reflection efficiency, strong stability and high precision of the stepping motor's rotation, the beam is deflected in different directions in two positions, 1 and 2. According to Bresenham The position points obtained by the algorithm are converted into corresponding pulse signals through STM32 to control the stepper motors of the 1st position and the 2nd position respectively to program the laser scanning track. The invention can select different scanning trajectories, scanning angles and laser point densities according to different requirements, the applicable laser wavelength band is wide, and the scanning precision is high. The scanning device runs smoothly and has good heat dissipation effect, which can maintain high-precision scanning work for a long time.

Description

Programmable laser scanning track device

Technical Field

The invention relates to the field of laser radars, in particular to a novel mechanical structure design which is mainly applied to occasions where the laser radars need to scan target objects. The problem that the scanning track of the laser radar cannot be changed according to different requirements is solved, and corresponding scanning requirements can be met.

Technical Field

The laser radar scanning system generally adopts an optical machine for scanning, the direction of a laser beam is deflected by an optical mechanical rotating device in front of a laser ranging sensor, and the laser beam moves along with a corresponding carrier to complete the scanning of a target. Common scanning modes of a scanning system of the laser radar include swing mirror type scanning, rotary polygon mirror scanning, optical fiber electric scanning, conical mirror scanning and the like. From the locus of the scanning points, the locus of the first three scanning modes is a straight line, and the locus of the ground point scanned by the conical mirror is an ellipse. The track of the optical machine scanning mainly comprises two linear scanning and conical scanning, the whole linear scanning in the motion process of the carrier is in a rectangular strip shape, although the scanning density is relatively low, the scanning speed is high, the range is large, and the data processing is simple. The scanning density of the cone scanning is dense, and data support can be better provided for subsequent data processing. The existing scanning modes can only perform one scanning track singly. The laser radar scanning device has the advantages of single scanning track, incapability of adapting to different scanning requirements and capability of changing the scanning track and adjusting the scanning angle compared with the defect of single common scanning track.

The invention designs a programmable laser scanning track device, innovatively controls scanning track points of a laser radar by programming a Bresenham algorithm to realize different scanning tracks, scanning angles and scanning grid densities, so that the laser radar can modularize to meet the scanning range and more use requirements under different requirements.

Disclosure of Invention

The invention relates to an optical-mechanical scanning device, which has the principle that an incident laser beam deflects according to scanning track points obtained by Bresenham algorithm to achieve various scanning tracks. The invention mainly aims at the defect that the scanning track can not be changed in the traditional scanning mode, the scanning track of the laser radar is programmed and controlled according to a Bresenham algorithm, and a device for programming the scanning track of the laser radar is designed, so that the scanning track, the scanning angle and the scanning grid density of the laser radar can be changed.

In order to realize the purpose of the invention, the following technical scheme is adopted for realizing the purpose: the device is a scanning system consisting of a reflecting mirror reflecting from the front surface, a stepping motor and an encoder. The scanning system derives position points according to Bresenham's algorithm, which are converted into corresponding pulse signals to control the 1-position and 2-position stepper motors, respectively. The stepping motors at the 1 position and the 2 position respectively drive the reflector at the 1 position and the reflector at the 2 position, which form an included angle of 135 degrees with the horizontal direction, to swing towards the Y direction and the X direction respectively, and the angle of position point conversion is obtained by a Bresenham algorithm to realize the desired scanning track.

The specific process is to input initial values, namely initial scanning center point position, scanning speed, scanning type and scanning angle. The parameters are obtained by an algorithm in a controller STM32, corresponding position points are stored, then the data are converted into corresponding pulse signals to be output to an encoder to respectively control a stepping motor of a shaft 1 and a stepping motor of a shaft 2, the stepping motor drives a reflector of the position 1 to swing for a certain angle towards the Y direction, then a laser beam translates for a certain distance along the plumb direction, and similarly, the stepping motor drives a reflector of the position 2 to swing for a certain angle towards the X direction, then the laser beam translates for a certain distance along the horizontal direction, so that the purpose that the specific laser beam scanning track is realized by respectively inputting the pulse signals converted by a Bresenham algorithm to the stepping motors of the shaft 1 and the shaft 2 to respectively control the reflector of the position 1 and the reflector of the position 2 to swing towards the Y direction and the X direction.

The invention has the beneficial effects that: on one hand, the scanning device can be modularized by utilizing an algorithm, the actual application range of the scanning device is increased, and the corresponding position and time parameters of each track point can be obtained; on the other hand, the reflection efficiency of the front surface reflection lens adopted by the invention to the laser with the wavelength range of 500 nm-1600 nm is more than 99%, and the laser beam is changed by applying the optical reflection principle, namely, the laser beam has no dispersion problem when deflecting the laser with different wavelengths or the laser with several wavelengths. The invention has the advantages of strong innovation, multiple functions, small volume, light weight, simple structure and good stability. The scanning device has stable operation, good heat dissipation effect, high reflection efficiency and good coaxiality, and can keep high-quality scanning work for a long time.

Drawings

FIG. 1 is a schematic view of the overall structure of a scanning device according to the present invention;

FIG. 2 is an exploded view of the scanning device of the present invention;

FIG. 3 is a view of the position mirror mount of the present invention 1;

FIG. 4 is a view of the position mirror mount of the present invention 2;

FIG. 5 is a schematic view of the 1 position motor mount of the present invention;

FIG. 6 is a block diagram of the 2 position motor mount of the present invention;

FIG. 7 is a view of the base structure of the present invention;

FIG. 8 is a view of the structure of the incident mirror holder of the present invention;

FIG. 9 is a flow chart of a control process of the present invention;

FIG. 10 is a diagram of the effect of track simulation according to the present invention.

[ description of reference ]

1 Integrated step motor

2 incident mirror bracket

3 incident mirror

41 position motor support

5M 3X 15 screw

61 position reflector support

7M 4X 15 screw

8 base

91 position reflector

10M 4X 20 screw

112 position mirror

122 position reflector bracket

132 position motor support

Detailed Description

In order to clearly explain the technical features of the present invention, the following detailed description of the present invention is provided with reference to the accompanying drawings.

As shown in fig. 1, a device for programming laser scanning track is mainly aimed at laser radar requiring specific scanning track. The specific implementation method is that after laser beams with the wavelength of 500 nm-1600 nm enter an incidence reflector forming 45 degrees with the laser beams, the laser beams are reflected by the front surface of the incidence reflector for 90 degrees and then enter a reflector surface forming 135 degrees with the horizontal plane at the position 1, the center of the laser beams is superposed with the center of the reflector at the position 1, then a stepping motor at the position 1 drives the reflector to rotate for a certain angle alpha, the front surface of the reflector reflects the laser beams for 45-2 alpha angles and then enters a reflector surface forming 135 degrees with the horizontal plane at the position 2, finally the laser beams drive the reflector to rotate for a certain angle beta by a stepping motor at the position 2, the front surface of the reflector reflects the laser beams for 45-2 beta angles, and the laser beams emitted after the laser beams are reflected by the front surfaces of the two reflectors at the time are deflected (2 beta, 2 alpha) in the plumb plane corresponding to position point coordinates (x, y).

At this time, as shown in fig. 9, firstly, parameters, that is, a desired initial scanning center point position, a scanning speed, a scanning type and a scanning angle, are input into the STM32, then, after a corresponding position point is calculated by Bresenham's algorithm in an operation module, data of the calculated position point is stored in a memory of the STM32, and is converted into a corresponding pulse signal to be output to an encoder of the stepping motor, and the 1-position stepping motor and the 2-position stepping motor are respectively controlled to rotate the calculated position point conversion angles in the Y-axis direction and the X-axis direction by inputting the corresponding pulse signal to the encoder of the 1-position stepping motor and the encoder of the 2-position stepping motor, respectively.

The angle of the mirror swing driven by the primary pulse signal is the same as the angle of the stepping motor rotation, and the stepping motor subdivision interpolation technology can control the motor to rotate 1 circle by 25000 steps at most, namely each step is 0.0144 degrees. The stepping motor drives the reflector to rotate 0.0144 degrees every time the stepping motor rotates 0.0144 degrees, the laser reflected by the front of the reflector deflects 0.0288 degrees, and the deflection angle of the laser can be accurately controlled through the characteristic, so that different scanning tracks are achieved, as shown in fig. 10, linear scanning, surface scanning and conical scanning can be obtained through simple simulation.

The biggest innovation of the invention is to introduce Bresenham algorithm to control the scanning motor to achieve different scanning tracks, and realize programmable laser scanning tracks to change the scanning tracks under different requirements. Since the positions of all lasers are known and corresponding data processing at the later stage can be called, the device can be applied to different laser radars with requirements on tracks due to the fact that the position points can be programmed, and modularization can be carried out. The laser scanning device has the advantages of multiple functions, small volume, light weight, simple structure and good stability. The scanning device has stable operation, good heat dissipation effect, high reflection efficiency and good coaxiality, and can keep high-quality scanning work for a long time.

The details of the present invention are not described in detail, but are known to those skilled in the art.

Claims

1. An apparatus for programmable laser scanning of a track, comprising: the device comprises a reflector bracket, a motor bracket, a laser reversing bracket and a base; it is characterized in that: the reflector bracket is used for fixing the front reflector and rotates along with the motor; the motor support is used for fixing the motor and the laser reversing support according to a certain space position requirement, and the structure of the motor support is fixed on the base; the laser reversing support deflects the direction of an incident laser beam by 45 degrees, so that the beam is emitted into the device as required; the base is used for fixing the position of the motor support and adjusting the height of the scanning device, and if the device is applied to the whole radar, the position of the base needs to be reserved.

2. A programmable laser scanning track arrangement according to claim 1, wherein: when the reflector bracket fixes the reflector, the rotation center of the reflector bracket is coplanar with the front surface of the reflector and is directly fixed on the motor, and the rotation angle is ensured to be consistent with the stepping angle.

3. A programmable laser scanning track arrangement according to claim 1, wherein: the motor bracket can fix a motor provided with the reflector bracket and is installed according to the relative space position required by the reflector design.

4. A programmable laser scanning track arrangement according to claim 1, wherein: the laser reversing support is fixedly arranged on the motor support, and the laser beam which is vertically incident is turned to 45 degrees and is incident into the reflector, so that the incident light is coaxial with the reflector fixed on the motor.

5. A programmable laser scanning track arrangement according to claim 1, wherein: the motor support is fixed according to the requirement on the required specific space position of the reflector, and the center height of the whole scanning device can be adjusted in the laser radar.