Semi-solid laser radar and point cloud coordinate determination method

Abstract

The invention discloses a semi-solid laser radar and a point cloud coordinate determination method. The semi-solid laser radar comprises a coded disc, a second photoelectric detector, a first photoelectric detector and a processor. The dark channel of the code disc comprises a groove and a light absorption structure filled in the groove; the distance between the surface, close to one side of the stator, of the bright channel of the code disc and the rotor is L1, the distance between the surface, close to one side of the stator, of the light absorption structure and the rotor is L2, and L1-L2 / L1 is smaller than or equal to 20%; the first photoelectric detector is used for converting a received first optical signal reflected by the to-be-detected object into a first electric signal and transmitting the first electric signal to the processor; the second photoelectric detector is used for converting a received second optical signal reflected in the rotation process of the coded disc into a second electric signal and transmitting the second electric signal to the processor; the processor is used for determining coordinates of a point cloud corresponding to the to-be-measured object according to the first electric signal and the second electric signal. According to the invention, the accuracy of the point cloud coordinates determined by the semi-solid laser radar can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of radar, and particularly to a semi-solid state lidar and a method for determining point cloud coordinates. Background Art

[0002] In a semi-solid state lidar, it is necessary to obtain angle information, and the most commonly used is an optoelectronic encoder.

[0003] An optoelectronic encoder is a sensor that can convert distance and angle into electrical signals and output them. In an ideal situation, the bright tracks and dark tracks on the code disk of the optoelectronic encoder are evenly distributed. The bright tracks can reflect the incident light, while the dark tracks will absorb the incident light. The photodetector in the optoelectronic encoder can receive the light reflected by the bright tracks of the rotating code disk and convert it into an electrical signal.

[0004] However, in the actually processed code disk, the dark tracks are milled by a tool, and the shape presented under a microscope is a concave pit. There is a slow change process at the junction of the bright tracks and the dark tracks, and some of the dark tracks will reflect light to the photodetector, affecting the accuracy of the electrical signal generated by the photodetector, and further affecting the accuracy of the point cloud coordinates determined by the semi-solid state lidar. Summary of the Invention

[0005] The present invention provides a semi-solid state lidar and a method for determining point cloud coordinates to solve the problem that the buffer area of the code disk in the existing optoelectronic encoder affects the accuracy of the point cloud coordinates determined by the semi-solid state lidar.

[0006] In a first aspect, an embodiment of the present invention provides a semi-solid state lidar, including a motor, an optoelectronic encoder, a first light source, a first photodetector, and a processor;

[0007] The motor includes a stator and a rotor;

[0008] The optoelectronic encoder includes a code disk, a second light source, and a second photodetector; the code disk is fixed on one side of the rotor close to the stator, and the second light source and the second photodetector are fixed on one side of the stator close to the rotor;

[0009] The code disk includes bright tracks and dark tracks, and the bright tracks and the dark tracks are arranged alternately in a circumferential direction with the center of the code disk as the center of the circle; the dark tracks include grooves and light-absorbing structures filled in the grooves; the distance between the surface of the bright track close to the stator and the rotor is L1, and the distance between the surface of the light-absorbing structure close to the stator and the rotor is L2, and |L1 - L2| / L1 ≤ 20%;

[0010] The first light source is used to emit a first optical signal to the object to be measured, wherein the first optical signal includes a continuously frequency-modulated laser signal;

[0011] The first photodetector is electrically connected to the processor, and is configured to receive the first optical signal reflected by the object to be measured, convert the first optical signal into a first electrical signal, and transmit the first electrical signal to the processor;

[0012] The second light source is used to emit a second optical signal to the code disk, wherein the second optical signal includes a continuous laser signal with a constant frequency;

[0013] The second photodetector is electrically connected to the processor, and is configured to receive the second optical signal reflected during the rotation of the code disk, convert the second optical signal into a second electrical signal, and transmit the second electrical signal to the processor; the second electrical signal includes a code disk position waveform signal;

[0014] The processor is configured to determine the coordinates of the point cloud corresponding to the object to be measured according to the first electrical signal and the second electrical signal.

[0015] Optionally, the surface of the light-absorbing structure close to the stator side and the surface of the bright track close to the stator side are in the same plane.

[0016] Optionally, the bright track includes a starting bright track, the dark track includes a starting dark track, and the starting bright track and the starting dark track are arranged adjacent to each other;

[0017] The width of the starting bright track is greater than or less than the width of any bright track other than the starting bright track in the code disk;

[0018] The width of the starting dark track is greater than or less than the width of any dark track other than the starting dark track in the code disk.

[0019] Optionally, the flatness of the surface of the light-absorbing structure close to the stator side is greater than a preset flatness;

[0020] The reflectivity of the bright track is greater than a preset reflectivity.

[0021] Optionally, the semi-solid lidar further includes a polygon prism, a galvanometer, and a galvanometer shaft;

[0022] The polygon prism is fixed on the side of the rotor away from the stator, and rotates around the rotation axis of the motor with the rotor;

[0023] The galvanometer is fixed on the galvanometer shaft and rotates around the galvanometer shaft;

[0024] The extending direction of the rotation axis intersects with the extending direction of the galvanometer shaft;

[0025] The first optical signal emitted by the first light source is incident on the object to be measured through the polygonal prism and the galvanometer mirror;

[0026] The first optical signal reflected by the object to be measured is incident on the first photodetector through the polygonal prism and the galvanometer mirror.

[0027] Second, an embodiment of the present invention provides a method for determining point cloud coordinates. The method for determining point cloud coordinates is executed by the semi-solid lidar as described in the first aspect. The method for determining point cloud coordinates includes:

[0028] Determine the distance, speed, and energy information of the point cloud corresponding to the object to be measured according to the first electrical signal;

[0029] Determine the encoder disk time information corresponding to the point cloud according to the second electrical signal;

[0030] Determine the coordinates of the point cloud according to the calibrated encoder disk position waveform signal, the encoder disk time information corresponding to the point cloud, and the distance, speed, and energy information of the point cloud.

[0031] Optionally, before determining the coordinates of the point cloud according to the calibrated encoder disk position waveform signal, the encoder disk time information corresponding to the point cloud, and the distance, speed, and energy information of the point cloud, it further includes:

[0032] Obtain M encoder disk position waveform signals from the second electrical signal;

[0033] Determine the calibrated encoder disk position waveform signal according to the M encoder disk position waveform signals.

[0034] Optionally, the encoder disk position waveform signal includes i rising edges and j falling edges, and the calibrated encoder disk position waveform signal includes i rising edges and j falling edges;

[0035] Determining the calibrated encoder disk position waveform signal according to the M encoder disk position waveform signals includes:

[0036] Determine the calibration time of the i-th rising edge of the calibrated encoder disk position waveform signal according to the time average value of the i-th rising edge of the M encoder disk position waveform signals;

[0037] Determine the calibration time of the j-th falling edge of the calibrated encoder disk position waveform signal according to the time average value of the j-th falling edge of the M encoder disk position waveform signals;

[0038] Determine the calibrated encoder disk position waveform signal according to the calibration time of the rising edge and the calibration time of the falling edge.

[0039] Optionally, before obtaining M encoder disk position waveform signals from the second electrical signal, the point cloud coordinate determination method further includes:

[0040] Controlling the motor to operate at a preset speed until the difference between the period of the encoder disk position waveform signal in the second electrical signal and a preset period meets a preset error range;

[0041] Obtaining M encoder disk position waveform signals from the second electrical signal includes:

[0042] When the motor operates at the preset speed, obtaining M encoder disk position waveform signals from the second electrical signal.

[0043] Optionally, obtaining M encoder disk position waveform signals from the second electrical signal includes:

[0044] Obtaining N encoder disk position waveform signals from the second electrical signal;

[0045] Randomly selecting M encoder disk position waveform signals that meet the requirements from the N encoder disk position waveform signals, where N > M.

[0046] In the technical solution of the embodiment of the present invention, by filling the grooves of the encoder disk with a light-absorbing structure and setting the surface of the bright track close to the stator side and the surface of the light-absorbing structure close to the stator side approximately in the same plane, the possibility of light reflection from the dark track can be reduced, the accuracy of the electrical signal generated by the second photodetector can be improved, and further, the accuracy of the point cloud coordinates determined by the semi-solid state lidar can be improved, solving the problem that the buffer area between the bright and dark tracks of the encoder disk in the existing optical encoder affects the accuracy of the point cloud coordinates determined by the semi-solid state lidar.

[0047] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. Description of the Drawings

[0048] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0049] Figure 1 It is a schematic structural diagram of a semi-solid state lidar provided by an embodiment of the present invention;

[0050] Figure 2 It is a sectional view of an encoder disk provided by an embodiment of the present invention;

[0051] Figure 3 Schematic structural diagram of a code disk provided by an embodiment of the present invention;

[0052] Figure 4 Flow chart of a method for determining point cloud coordinates provided by an embodiment of the present invention;

[0053] Figure 5 Flow chart of another method for determining point cloud coordinates provided by an embodiment of the present invention;

[0054] Figure 6 Flow chart of yet another method for determining point cloud coordinates provided by an embodiment of the present invention. Detailed implementation manners

[0055] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0056] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices. The terms "upper", "lower", "left", "right", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to illustrate the relative positional relationship between each component or component part, and do not particularly limit the specific installation orientation of each component or component part.

[0057] Figure 1 Schematic structural diagram of a semi-solid state lidar provided by an embodiment of the present invention, Figure 2 Cross-sectional view of a code disk provided by an embodiment of the present invention, refer to Figure 1 and Figure 2, the semi-solid state lidar in the embodiments of the present invention includes a motor 10, an optoelectronic encoder 20, a first light source 30, a first photodetector 40, and a processor 50. The motor 10 includes a stator 11 and a rotor 12. The optoelectronic encoder 20 includes a code disk 21, a second light source 22, and a second photodetector 23. The code disk 21 is fixed on one side of the rotor 12 close to the stator 11, and the second light source 22 and the second photodetector 23 are fixed on one side of the stator 11 close to the rotor 12. The code disk 21 includes bright tracks 211 and dark tracks 212, and the bright tracks 211 and the dark tracks 212 are arranged alternately in a circumferential direction with the center of the code disk 21 as the center of the circle. The dark track 212 includes a groove 2121 and a light-absorbing structure 2122 filled in the groove 2121. The distance between the surface of the bright track 211 close to the stator 11 and the rotor 12 is L1, and the distance between the surface of the light-absorbing structure 2122 close to the stator 11 and the rotor 12 is L2, and |L1 - L2| / L1 ≤ 20%.

[0058] The first light source 30 is used to emit a first optical signal to the object to be measured. Among them, the first optical signal includes a continuously frequency-modulated laser signal. The first photodetector 40 is electrically connected to the processor 50 and is used to receive the first optical signal reflected by the object to be measured, convert the first optical signal into a first electrical signal, and then transmit it to the processor 50. The second light source 22 is used to emit a second optical signal to the code disk 21. Among them, the second optical signal includes a continuously and frequency-invariant laser signal. The second photodetector 23 is electrically connected to the processor 50 and is used to receive the second optical signal reflected during the rotation of the code disk 21, convert the second optical signal into a second electrical signal, and then transmit it to the processor 50. The second electrical signal includes a code disk position waveform signal. The processor 50 is used to determine the coordinates of the point cloud corresponding to the object to be measured according to the first electrical signal and the second electrical signal.

[0059] Optionally, refer to Figure 1 , the semi-solid state lidar further includes a polygon prism 60, a galvanometer 70, and a galvanometer shaft 80. The polygon prism 60 is fixed on one side of the rotor 12 away from the stator 11 and rotates around the rotating shaft 13 of the motor 10 with the rotor 12. The galvanometer 70 is fixed on the galvanometer shaft 80 and rotates around the galvanometer shaft 80. The extending direction of the rotating shaft 13 intersects with the extending direction of the galvanometer shaft 80. The first optical signal emitted by the first light source 30 is incident on the object to be measured through the polygon prism 60 and the galvanometer 70. The first optical signal reflected by the object to be measured is incident on the first photodetector 40 through the polygon prism 60 and the galvanometer 70.

[0060] Exemplarily, the polygonal prism 60 that rotates around the rotation axis 13 with the rotor 12 can enable the first light source 30 to perform horizontal scanning of the object to be measured, and the galvanometer 70 that rotates around the galvanometer axis 80 can enable the first light source 30 to perform vertical scanning of the object to be measured. The first optical signal emitted by the first light source 30 will sequentially pass through the galvanometer 70 and the polygonal prism 60 and be incident on the object to be measured. The first optical signal incident on the object to be measured will also sequentially pass through the polygonal prism 60 and the galvanometer 70 and be incident on the first photodetector 40. The first photodetector 40 can convert the received first optical signal into a first electrical signal and transmit the first electrical signal to the processor 50. The processor 50 can determine the distance, speed, and energy information of the point cloud corresponding to the object to be measured based on the first electrical signal.

[0061] In the embodiment of the present invention, the code disk 21 adopts a reflective structure. The second light source 22 and the second photodetector 23 are arranged on the same side. The second light source 22 emits a second optical signal onto the bright track 211 and the dark track 212 of the code disk 21. The bright track 211 of the code disk 21 reflects the second optical signal to the second photodetector 23, and the dark track 212 of the code disk 21 absorbs the second optical signal. The second photodetector 23 can convert the received second optical signal into a second electrical signal and transmit the second electrical signal to the processor 50. The processor 50 can determine the code disk time information corresponding to the point cloud based on the second electrical signal.

[0062] After the processor 50 determines the code disk time information corresponding to each point cloud corresponding to the object to be measured and the distance, speed, and energy information of each point cloud, it can determine the coordinates of each point cloud based on the pre-determined and stored calibrated code disk position waveform signal, the code disk time information corresponding to each point cloud, and the distance, speed, and energy information of each point cloud, and then generate a three-dimensional point cloud image corresponding to the object to be measured.

[0063] It can be understood that to prevent the dark track 212 from reflecting the second optical signal to the second photodetector 23, the embodiment of the present invention sets an absorbent structure 2122 to be filled in the groove 2121 of the dark track 212. To achieve the best effect, the surface of the dark track 212 after filling the absorbent structure 2122 should be in the same plane as the surface of the two tracks 211. However, in the actual preparation process, there will inevitably be errors. But to minimize the possibility of the dark track reflecting the second optical signal to the second photodetector 23, the allowable error range is strictly specified. Therefore, the embodiment of the present invention sets the distance L1 between the surface of the bright track 211 close to the stator 11 and the rotor 12, and the distance L2 between the surface of the absorbent structure 2122 close to the stator 11 and the rotor 12 to satisfy the following corresponding relationship: |L1 - L2| / L1 ≤ 20%.

[0064] In an embodiment of the present invention, by filling the groove 2121 of the code disk dark channel 212 with a light-absorbing structure 2122 and setting the surface of the bright channel 211 close to the stator 11 and the surface of the light-absorbing structure 2122 close to the stator 11 to be approximately in the same plane, the possibility of the dark channel 212 reflecting light can be reduced, the accuracy of the electrical signal generated by the second photodetector 23 can be improved, and further, it is beneficial to improve the accuracy of the point cloud coordinates determined by the semi-solid state lidar, solving the problem that the buffer area between the bright and dark channels of the code disk in the existing optical encoder affects the accuracy of the point cloud coordinates determined by the semi-solid state lidar.

[0065] It can be understood that when the rotor 12 rotates at a high speed, air vortices will be generated. If particles are adsorbed on the code disk 21, the irregular movement of gas molecules in the air vortices will cause the particles adsorbed on the code disk 21 to be extremely unstable (shaking left and right on the adsorption surface). If the particles happen to be in the reflective area at the junction of the bright and dark channels, more unstable factors may be brought. Therefore, by filling the groove 2121 of the code disk dark channel 212 with a light-absorbing structure 2122, it is also possible to prevent tiny particulate matters such as flying dust from gathering in the groove 2121, thereby avoiding the emergence of more unstable factors.

[0066] As a feasible implementation manner, the surface of the light-absorbing structure 2122 close to the stator 11 and the surface of the bright channel 211 close to the stator 11 are located in the same plane.

[0067] Exemplarily, when preparing the above-mentioned code disk 21, a planarization process can be added to achieve that the surface of the light-absorbing structure 2122 close to the stator 11 and the surface of the bright channel 211 close to the stator 11 are located in the same plane. In this way, the possibility of the dark channel reflecting the second optical signal to the second photodetector 23 can be further reduced, the accuracy of the second electrical signal can be further improved, and further, it is beneficial to improve the accuracy of the point cloud coordinates determined by the semi-solid state lidar.

[0068] Figure 3 It is a schematic structural diagram of a code disk provided by an embodiment of the present invention. Refer to Figure 3 , the bright channel 211 includes a starting bright channel 211A, the dark channel 212 includes a starting dark channel 212A, and the starting bright channel 211A and the starting dark channel 212A are arranged adjacent to each other. The width of the starting bright channel 211A is greater than or less than the width of any bright channel 211 other than the starting bright channel 211A in the code disk 21. The width of the starting dark channel 212A is greater than or less than the width of any dark channel 212 other than the starting dark channel 212A in the code disk 21.

[0069] Exemplarily, the second electrical signal includes a plurality of periodically varying code disk position waveform signals. One code disk position waveform signal can be obtained for each rotation of the code disk. The code disk position waveform signal includes high and low levels arranged alternately. The high level corresponds to the bright track 211 of the code disk 21, and the low level corresponds to the dark track of the code disk 22. In order to distinguish the plurality of code disk position waveform signals in the second electrical signal, it is necessary to set a starting bright track 211A that can be distinguished from other bright tracks 211, and a starting dark track 212A that can be distinguished from other dark tracks 212. It can be understood that the wider the width of the bright track 211, the longer the duration of the corresponding high level, and the wider the width of the dark track 212, the longer the duration of the corresponding low level. Therefore, a starting bright track 211A with a width different from that of other bright tracks can be set on the code disk 21, and a starting dark track 211B with a width different from that of other dark tracks can be set. In Figure 3 In the shown embodiment, the width of the starting bright track 211A is greater than the width of any bright track 211 other than the starting bright track 211A, and the width of the starting dark track 212A is greater than the width of any dark track 211 other than the starting dark track 212A. It should be noted that in other embodiments, the width of the starting bright track 211A can also be set to be less than the width of any bright track 211 other than the starting bright track 211A, and the width of the starting dark track 212A can be set to be less than the width of any dark track 211 other than the starting dark track 212A.

[0070] As a feasible implementation manner, the flatness of the surface of the light absorption structure 2122 close to the stator 11 is greater than a preset flatness. The reflectivity of the bright track 211 is greater than a preset reflectivity.

[0071] It can be understood that although the surface of the bright track 211 close to the stator 11 and the surface of the light absorption structure 2122 close to the stator 11 are approximately in the same plane, or even in the same plane, if the surface of the light absorption structure 2122 that receives the second optical signal is rough, it is possible that some of the incident second optical signals are reflected back to the second photodetector 23. Therefore, when preparing the light absorption structure 2122, the surface of the light absorption structure 2122 close to the stator 11 can be polished to ensure that the surface of the light absorption structure 2122 close to the stator 11 is smooth enough, that is, its flatness is greater than the preset flatness. It should be noted that the specific value of the preset flatness in the embodiments of the present invention is not limited, and those skilled in the art can set it according to the actual situation.

[0072] By controlling the reflectivity of the bright track 211 to be greater than the preset reflectivity, more second optical signals can be reflected by the bright track 211 to the second photodetector 23. At this time, even if the absorption structure 2122 fails to absorb all the second optical signals and causes some second optical signals to be reflected to the second photodetector 23, the reflected second optical signals will not be determined as high level because they are too weak, which can further ensure the accuracy of the second optical signals, and thus is beneficial to improving the accuracy of the point cloud coordinates determined by the semi-solid state lidar.

[0073] An embodiment of the present invention further provides a method for determining point cloud coordinates. The method for determining point cloud coordinates is executed by the semi-solid state lidar provided in the above embodiment, and is specifically implemented by a processor in the semi-solid state lidar. Figure 4 is a flowchart of a method for determining point cloud coordinates provided by an embodiment of the present invention. Refer to Figure 4 , the method for determining point cloud coordinates in an embodiment of the present invention includes:

[0074] S110. Determine the distance, speed, and energy information of the point cloud corresponding to the object to be measured according to the first electrical signal.

[0075] Exemplarily, refer to Figure 1 , the processor 50 is electrically connected to the first photodetector 40, and can receive the first electrical signal generated by the first photodetector 40 according to the first optical signal reflected by the object to be measured, and determine the distance, speed, and energy information of the point cloud corresponding to the object to be measured according to the first electrical signal.

[0076] S120. Determine the encoder time information corresponding to the point cloud according to the second electrical signal.

[0077] Exemplarily, refer to Figure 1 , the processor 50 is electrically connected to the second photodetector 23, and can receive the second electrical signal generated by the second photodetector 23 according to the second optical signal reflected by the encoder 21, and determine the distance, speed, and energy information of the point cloud corresponding to the object to be measured according to the first electrical signal.

[0078] S130. Determine the coordinates of the point cloud according to the calibrated encoder position waveform signal, the encoder time information corresponding to the point cloud, and the distance, speed, and energy information of the point cloud.

[0079] Exemplarily, refer to Figure 1 , after the processor 50 determines the encoder time information corresponding to each point cloud corresponding to the object to be measured and the distance, speed, and energy information of each point cloud, it can determine the coordinates of each point cloud according to the pre-determined and stored calibrated encoder position waveform signal, the encoder time information corresponding to each point cloud, and the distance, speed, and energy information of each point cloud, and then generate a three-dimensional point cloud image corresponding to the object to be measured.

[0080] In the embodiment of the present invention, the method for determining the point cloud coordinates in the embodiment of the present invention is executed by the semi-solid state lidar in the above embodiment. The setting of the dark channels in the encoder of the semi-solid state lidar can reduce the possibility of the reflected light of the dark channels, improve the accuracy of the second electrical signal generated by the second photodetector, and thus is beneficial to improving the accuracy of the method for determining the point cloud coordinates.

[0081] Figure 5 It is a flowchart of another method for determining point cloud coordinates provided by the embodiment of the present invention. Figure 5 The shown embodiment enriches the process of the method for determining point cloud coordinates. Referring to Figure 5 , the method for determining point cloud coordinates in the embodiment of the present invention includes:

[0082] S210. Obtain M encoder position waveform signals from the second electrical signal.

[0083] As a feasible implementation manner, obtaining M encoder position waveform signals from the second electrical signal includes: obtaining N encoder position waveform signals from the second electrical signal; randomly selecting M encoder position waveform signals that meet the requirements from the N encoder position waveform signals, where N > M.

[0084] First, obtain N encoder position waveform signals from the second electrical signal, and these N encoder position waveform signals are continuous. Then, randomly select M encoder position waveform signals from these N encoder position waveform signals. Since the selection of these M encoder position waveform signals is random, its expectation is 0 and the variance is a constant, which is beneficial to improving the accuracy of the calibrated encoder position waveform signal determined subsequently based on the M encoder position waveform signals.

[0085] S220. Determine the calibrated encoder position waveform signal according to the M encoder position waveform signals.

[0086] It should be noted that the encoder position waveform signal includes i rising edges and j falling edges, and the calibrated encoder position waveform signal includes i rising edges and j falling edges.

[0087] As a feasible implementation manner, determining the calibrated encoder position waveform signal according to the M encoder position waveform signals includes: determining the calibration time of the i-th rising edge of the calibrated encoder position waveform signal according to the time average value of the i-th rising edge of the M encoder position waveform signals. Determining the calibration time of the j-th falling edge of the calibrated encoder position waveform signal according to the time average value of the j-th falling edge of the M encoder position waveform signals. Determining the calibrated encoder position waveform signal according to the calibration time of the rising edge and the calibration time of the falling edge.

[0088] It can be understood that referring to Figure 1, in an ideal situation, the plane (stator plane) where the second light source 22 and the second photodetector 23 in the optoelectronic encoder 20 are located is relatively parallel to the plane (rotor plane) where the code disk 21 in the optoelectronic encoder 20 is located. Thus, during all rotation periods when the code disk 21 rotates with the rotor 12, the waveform of the code disk position signal output to the processor 50 should be fixed and unchanged. However, during the rotation of the motor 10, there must be a slight deviation relative to the rotating shaft 13, resulting in a deviation angle between the plane of the rotor 12 and the ideal rotor plane. In addition, the semi-solid state lidar is installed in the vehicle, and the vehicle bounces up and down during driving. Generally, the semi-solid state lidar cannot isolate all external vibrations. Therefore, the vibration of the vehicle will also be transmitted to the rotor 12 of the semi-solid state lidar, further causing a larger deviation angle.

[0089] To eliminate the deviation caused by the above situation as much as possible, obtain an accurate calibrated code disk position waveform signal, and improve the accuracy of the point cloud coordinates, the embodiment of the present invention sets a scheme for determining the calibrated code disk position waveform signal according to M randomly obtained code disk position waveform signals.

[0090] S230. Determine the distance, speed, and energy information of the point cloud corresponding to the object to be measured according to the first electrical signal.

[0091] S240. Determine the code disk time information corresponding to the point cloud according to the second electrical signal.

[0092] S250. Determine the coordinates of the point cloud according to the calibrated code disk position waveform signal, the code disk time information corresponding to the point cloud, and the distance, speed, and energy information of the point cloud.

[0093] Figure 6 It is a flowchart of another method for determining the point cloud coordinates provided by the embodiment of the present invention. Figure 6 The shown embodiment enriches the process of the method for determining the point cloud coordinates. Refer to Figure 6 , the method for determining the point cloud coordinates in the embodiment of the present invention includes:

[0094] S310. Control the motor to run at a preset speed until the difference between the period of the code disk position waveform signal in the second electrical signal and the preset period meets the preset error range.

[0095] Refer to Figure 1 , it can be understood that the stability of the rotation speed of the motor 10 is also an important factor affecting the second electrical signal. Therefore, to ensure the accuracy of the second electrical signal, it is also necessary to ensure that the motor can run at a preset speed uniformly and stably. The processor 50 is electrically connected to the control end of the motor, and the PID control method can be combined to realize the control of the motor rotation speed.

[0096] S320. When the motor runs at a preset speed, obtain M encoder position waveform signals from the second electrical signal.

[0097] By setting to obtain M encoder position waveform signals from the second electrical signal when the motor runs at a preset speed, the accuracy of the obtained M encoder position waveform signals can be ensured.

[0098] S330. Determine the calibrated encoder position waveform signal according to the M encoder position waveform signals.

[0099] S340. Determine the distance, speed, and energy information of the point cloud corresponding to the object to be measured according to the first electrical signal.

[0100] S350. Determine the encoder time information corresponding to the point cloud according to the second electrical signal.

[0101] S360. Determine the coordinates of the point cloud according to the calibrated encoder position waveform signal, the encoder time information corresponding to the point cloud, and the distance, speed, and energy information of the point cloud.

[0102] The above specific embodiments do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub - combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A semi-solid laser radar, characterized in that: It includes a motor, a photoelectric encoder, a first light source, a first photoelectric detector and a processor; The motor comprises a stator and a rotor; The photoelectric encoder comprises a code disk, a second light source and a second photodetector; the code disk is fixed on a side of the rotor close to the stator, and the second light source and the second photodetector are fixed on a side of the stator close to the rotor; The code disk includes a bright track and a dark track, and the bright track and the dark track are arranged alternately in the circumferential direction with the center of the code disk as the center of the circle; the dark track includes a groove and a light absorbing structure filled in the groove; the distance between the surface of the bright track close to the stator and the rotor is L1, and the distance between the surface of the light absorbing structure close to the stator and the rotor is L2, and |L1-L2| / L1≤20%; The first light source is used to transmit a first light signal to the object to be measured, wherein the first light signal comprises a continuously frequency modulated laser signal; The first photodetector is electrically connected to the processor, and is used to receive the first light signal reflected by the object to be detected, and convert the first light signal into a first electrical signal and transmit it to the processor; The second light source is used to transmit a second light signal to the code disk, wherein the second light signal comprises a continuous laser signal with a constant frequency; The second photodetector is electrically connected to the processor, and is used to receive a second optical signal reflected during the rotation of the code disk, and convert the second optical signal into a second electrical signal and transmit it to the processor; the second electrical signal includes a code disk position waveform signal; The processor is used to determine the coordinates of the point cloud corresponding to the object to be measured according to the first electrical signal and the second electrical signal.

2. The semi-solid laser radar according to claim 1, characterized in that: The surface of the light absorbing structure close to the stator and the surface of the bright channel close to the stator are located in the same plane.

3. The semi-solid laser radar according to claim 1, characterized in that: The bright path includes a starting bright path, the dark path includes a starting dark path, and the starting bright path is arranged adjacent to the starting dark path; The width of the initial bright track is greater than or less than the width of any bright track in the code disk except the initial bright track; The width of the starting dark channel is greater than or less than the width of any dark channel in the code disk except the starting dark channel.

4. The semi-solid laser radar according to claim 1, characterized in that: The flatness of the surface of the light absorbing structure on a side close to the stator is greater than a preset flatness; The reflectivity of the bright channel is greater than a preset reflectivity.

5. The semi-solid laser radar according to claim 1, characterized in that: The semi-solid laser radar also includes a polygonal prism, a galvanometer and a galvanometer axis; The polygonal prism is fixed on a side of the rotor away from the stator, and rotates around the rotating shaft of the motor along with the rotor; The galvanometer is fixed on the galvanometer axis and rotates around the galvanometer axis; The extension direction of the rotating shaft intersects with the extension direction of the galvanometer axis; The first light signal emitted by the first light source is incident on the object to be measured via the polygonal prism and the galvanometer; The first light signal reflected by the object to be measured is incident on the first photodetector via the polygonal prism and the galvanometer.

6. A method for determining point cloud coordinates, the method for determining point cloud coordinates being performed by a semi-solid laser radar according to any one of claims 1 to 5, characterized in that: The point cloud coordinate determination method comprises: Determine the distance, speed and energy information of the point cloud corresponding to the object to be measured according to the first electrical signal; Determine the code disk time information corresponding to the point cloud according to the second electrical signal; The coordinates of the point cloud are determined according to the calibration code disk position waveform signal, the code disk time information corresponding to the point cloud, and the distance, speed and energy information of the point cloud.

7. The method for determining point cloud coordinates according to claim 6, characterized in that: Before determining the coordinates of the point cloud according to the calibration code disk position waveform signal, the code disk time information corresponding to the point cloud, and the distance, speed and energy information of the point cloud, the method further includes: Obtaining M code disk position waveform signals from the second electrical signal; The calibration code disk position waveform signal is determined according to the M code disk position waveform signals.

8. The method for determining point cloud coordinates according to claim 7, characterized in that: The code disk position waveform signal includes i rising edges and j falling edges, and the calibration code disk position waveform signal includes i rising edges and j falling edges; Determining the calibration code disk position waveform signal according to the M code disk position waveform signals comprises: Determine the calibration time of the i-th rising edge of the calibration code disk position waveform signal according to the time average of the i-th rising edges of the M code disk position waveform signals; Determine the calibration time of the j-th falling edge of the calibration code disk position waveform signal according to the time average of the j-th falling edges of the M code disk position waveform signals; The calibration code disk position waveform signal is determined according to the calibration time of the rising edge and the calibration time of the falling edge.

9. The method for determining point cloud coordinates according to claim 7, characterized in that: Before acquiring M code disk position waveform signals from the second electrical signal, the point cloud coordinate determination method further includes: Controlling the motor to run at a preset speed until the difference between the period of the encoder position waveform signal in the second electrical signal and a preset period satisfies a preset error range; Acquiring M code disk position waveform signals from the second electrical signal, comprising: When the motor runs at the preset speed, M code disk position waveform signals are obtained from the second electrical signal.

10. The method for determining point cloud coordinates according to claim 7, characterized in that: Acquiring M code disk position waveform signals from the second electrical signal, comprising: Acquire N code disk position waveform signals from the second electrical signal; Randomly select M code disk position waveform signals from the N code disk position waveform signals, where N>M.

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