WO2023050905A1 - 激光雷达的校准方法、激光雷达以及校准系统 - Google Patents

激光雷达的校准方法、激光雷达以及校准系统 Download PDF

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Publication number
WO2023050905A1
WO2023050905A1 PCT/CN2022/099753 CN2022099753W WO2023050905A1 WO 2023050905 A1 WO2023050905 A1 WO 2023050905A1 CN 2022099753 W CN2022099753 W CN 2022099753W WO 2023050905 A1 WO2023050905 A1 WO 2023050905A1
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Prior art keywords
rotating mirror
motor
information
calibration
target position
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PCT/CN2022/099753
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English (en)
French (fr)
Inventor
姚又友
向少卿
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上海禾赛科技有限公司
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Publication of WO2023050905A1 publication Critical patent/WO2023050905A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/497—Means for monitoring or calibrating

Definitions

  • the present disclosure relates to the field of photoelectric detection, and in particular to a laser radar calibration method, a computer-readable storage medium, a laser radar and a calibration system.
  • the calibration is performed when the laser radar has not yet been assembled, and the rotating parts in the laser radar are fixed by mechanical tooling, so that Fix the pointing of the laser radar output beam, so as to maintain the stability of the product attitude and the stability of the laser radar echo signal during the calibration process.
  • the specific calibration method is to set target boards with different reflectivities at one or more fixed distances, so that the lidar rotates, and the laser emission direction points to different target boards.
  • the lidar housing is not assembled first, and further production processes such as housing assembly are required after the calibration is completed.
  • the target board is far away from the lidar, which will significantly occupy the space of the production site. Since the lidar is usually produced in a clean room, space resources are more precious.
  • the above calibration method has a significant adverse effect on the layout of the production line.
  • the rotation angle of the laser radar can also be fixed by controlling the motor.
  • the traditional motor control method is to generate a sine wave power supply with adjustable frequency and voltage from the perspective of power supply.
  • a DC-to-AC process needs to be performed inside (or an external drive circuit).
  • the brushless motor includes a brushless DC motor (Brushless Direct Current Motor, BLDCM) and a permanent magnet synchronous motor (Permanent Magnet Synchronous Motor, PMSM).
  • the rotor of the permanent magnet synchronous motor PMSM is a permanent magnet, and there are three-phase windings on the stator, which are symmetrically distributed in a Y-shaped connection, with a difference of 120° in space to form a permanent magnet synchronous
  • the three-phase stationary coordinate system ABC of the motor PMSM Its working principle is: a constant rotating magnetic field is generated in the stator to drive the rotor to rotate continuously. In order to ensure the smooth motion performance of the motor, the size of this rotating magnetic field is constant. However, it is difficult to control the three phase voltages separately, and an efficient and precise control scheme is urgently needed to achieve effective control of the motor.
  • the present invention relates to a laser radar calibration method, wherein the laser radar includes a rotating mirror and a motor that drives the rotating mirror to rotate, and the calibration method includes:
  • S13 Calibrate the laser radar according to the echo pulse information obtained when the rotating mirror is at the at least one target position.
  • the step S12 includes: adjusting the vector size and/or duty cycle of each space vector voltage in the control voltage to obtain the motor torque output in a specified direction, so that the rotating mirror reaches the desired the target location.
  • the step S12 includes: adjusting the control voltage of the motor according to the at least one target position and the load information corresponding to the rotating mirror, so that the rotating mirror rotates to the at least a target location.
  • the reverse torque is obtained according to the load information of the rotating mirror, and the torque output of the motor is corrected.
  • the step S12 further includes: during the rotation process of the motor, acquiring deviation position information of the rotating mirror, and adjusting the control voltage according to the deviation position information until the rotating mirror reach the target location.
  • the deviation position information is acquired according to the current position and the target position of the rotating mirror.
  • step S12 further includes: during the rotation of the motor, acquiring current circuit parameter information, and adjusting the control voltage according to the deviation position information and the circuit parameter information until the rotation The mirror reaches the target position.
  • the circuit parameter information is determined according to the current information of the motor.
  • the lidar further includes a code disc
  • the calibration method further includes: detecting the current position of the rotating mirror through the code disc.
  • the calibration method further includes: the laser radar emits a detection laser pulse, and obtains echo pulses emitted by the detection laser pulse to a plurality of targets;
  • the calibration parameter of the lidar is determined by the echo pulse information respectively corresponding to the plurality of targets obtained when the at least one target position is located.
  • the multiple targets may respectively correspond to different measurement information, and the calibration parameters are used to calibrate the corresponding measurement information.
  • the echo pulse information includes at least one of the leading edge, pulse width, slope, and peak value of the echo pulse
  • the calibration method further includes: based on the calibration parameters, by The data of the calibration calibration parameters are calculated and processed, and the calibration calibration table of the lidar is established.
  • the invention also relates to a computer-readable storage medium comprising computer-executable instructions stored thereon, wherein said executable instructions, when executed by a processor, implement the calibration method as described above.
  • the present invention also relates to a laser radar, including a rotating mirror and a motor that drives the rotating mirror to rotate, wherein the laser radar also includes:
  • a position sensor configured to detect position information of the rotating mirror
  • control unit coupled to the motor and the position sensor, configured to:
  • the position sensor is an encoder disc, and the position information is an angular position.
  • the lidar further includes a multi-phase inverter drive circuit, the multi-phase inverter drive circuit is coupled between the control unit and the motor, configured to Drive the motor to work under control.
  • control voltage is synthesized using a part of the plurality of space vector voltages.
  • the multi-phase inverter driving circuit is a three-phase inverter driving circuit
  • the plurality of space vector voltages are six space vector voltages
  • some of the plurality of space vector voltages are two Space vector voltage.
  • control unit adjusts the vector size and/or duty cycle of each space vector voltage in the control voltage by controlling the switch state and duration of the multiple inverter drive circuits,
  • the torque output of the motor in a specified direction is obtained to control the motor to stop and point to a fixed direction.
  • the control unit obtains the deviation position information of the rotating mirror, and adjusts the control voltage according to the deviation position information until the rotating mirror reaches the target location.
  • the control unit obtains current circuit parameter information, and adjusts the control voltage according to the deviation position information and the circuit parameter information until the rotating mirror reach the target location.
  • the present invention further includes a transmitting unit and a receiving unit, wherein the transmitting unit is configured to transmit a detection laser pulse, and the receiving unit is configured to obtain echo pulses emitted by the detection laser pulse to a plurality of targets,
  • the control unit is further configured to determine the calibration parameters of the lidar according to the echo pulse information respectively corresponding to a plurality of targets obtained when the rotating mirror is at the at least one target position.
  • the plurality of targets may respectively have different distances and/or reflectances.
  • the echo pulse information includes at least one of the leading edge, pulse width, slope, and peak value of the echo pulse, and the control unit, based on the calibration parameters, through the calibration
  • the data of the calibration parameters are calculated and processed, and a calibration calibration table of the lidar is established.
  • the lidar further includes a computer-readable storage medium, including computer-executable instructions stored thereon, and the executable instructions implement the calibration method as described above when executed by the control unit .
  • the invention also relates to a calibration system comprising:
  • an alignment aid comprising at least one target arranged in different orientations
  • the Lidar includes a rotating mirror and a motor that drives the rotation of the rotating mirror, and the Lidar also includes:
  • a position sensor configured to detect position information of the rotating mirror
  • control unit coupled to the motor and the position sensor, configured to:
  • the at least one target position corresponds to the at least one target object arranged in different orientations.
  • the present invention utilizes the space vector voltage modulation technology and the corresponding inverter drive circuit to realize that the motor can stop at a specified angle, thereby fixing the laser radar outgoing light pointing, thereby providing a more efficient and accurate motor control mode, and for non-working state
  • the motor also enables accurate angle control, improving the efficiency of calibration operations.
  • the present invention realizes the separation of laser radar hardware production and calibration parameters by combining relatively advanced motor drive algorithm and laser radar calibration technology. Since the calibration process usually needs to occupy a large space, the present invention can avoid the hardware production process. The clean room space is occupied by the calibration process, which improves space utilization, improves production efficiency, optimizes production links, and helps reduce radar production costs.
  • FIG. 1A shows a schematic diagram of lidar calibration according to an embodiment of the present invention
  • FIG. 1B shows a schematic diagram of a scanning unit of a lidar
  • Fig. 2 shows a flow chart of a laser radar calibration method according to an embodiment of the present invention
  • Fig. 3 shows a schematic diagram of a permanent magnet synchronous motor
  • Fig. 4 shows the locus diagram that the phase voltage of an embodiment of the present invention is converted into the control voltage vector
  • FIG. 5A shows a schematic diagram of a three-phase inverter drive circuit according to an embodiment of the present invention
  • Fig. 5B shows the equivalent circuit diagram of Fig. 5A in the basic voltage space vector U 4 (100) state
  • Fig. 6 shows the schematic diagram of space vector voltage in ABC coordinate system and ⁇ coordinate system of an embodiment of the present invention
  • FIG. 7A shows a schematic diagram of lidar calibration according to an embodiment of the present invention.
  • FIG. 7B shows a schematic diagram of lidar calibration according to an embodiment of the present invention.
  • FIG. 7C shows a schematic diagram of lidar calibration according to an embodiment of the present invention.
  • Fig. 8 shows the overall block diagram of PID controller
  • Fig. 9 shows a schematic diagram of PID control according to an embodiment of the present invention.
  • first and second are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features.
  • a feature defined as “first” or “second” may explicitly or implicitly include one or more of said features.
  • “plurality” means two or more, unless otherwise specifically defined.
  • connection should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection.
  • Connected, or integrally connected it can be mechanically connected, or electrically connected, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediary, and it can be the internal communication of two components or the interaction of two components relation.
  • a first feature being “on” or “under” a second feature may include direct contact between the first and second features, or may include the first and second features Not in direct contact but through another characteristic contact between them.
  • “on”, “above” and “above” the first feature on the second feature include that the first feature is directly above and obliquely above the second feature, or simply means that the level of the first feature is higher than that of the second feature.
  • "Below”, “below” and “under” the first feature to the second feature include that the first feature is directly above and obliquely above the second feature, or simply means that the first feature has a lower horizontal height than the second feature.
  • FIG. 1A shows a schematic diagram of a laser radar calibration
  • FIG. 1B shows a schematic diagram of a scanning unit of a laser radar.
  • the lidar 20 includes a rotating mirror 21 and a motor 22 that drives the rotating mirror 21 to rotate, and the two constitute a scanning unit of the lidar 20 .
  • the rotating mirror 21 has a rotation axis O and can rotate and/or reciprocate around the rotation axis O.
  • the rotating mirror 21 has a reflective surface on which the laser beam L emitted by the laser of the laser radar 20 is received, and the laser beam R is reflected into the three-dimensional space outside the laser radar.
  • the rotating mirror 21 As the rotating mirror 21 rotates around the rotation axis O, the reflective surface will reflect the laser beam L in different directions, which can cover a certain range in three-dimensional space and constitute the field of view FOV of the laser radar 20 .
  • the rotating mirror 21 may include one or more rotating axes O, for example, including a scanning rotating axis in a horizontal direction and a scanning rotating axis in a vertical direction, all of which are within the scope of the present invention.
  • the laser radar 20 also includes a control unit 24 for controlling the rotation of the motor 21 . As shown in FIG.
  • a plurality of targets 311 are set at different orientations (different angles and/or different positions) around the lidar, such as the target 311-1 shown in FIG. 1A , the target The objects 311-2, ... and the target object 311-n control the rotation of the motor 24, point the laser emission direction to different target plates, and establish the relationship between the pulse width, the front edge and the real distance by measuring the pulse width and front edge of the echo. The corresponding relationship to complete the lidar calibration.
  • FIG. 2 shows a flowchart of a laser radar calibration method 10 according to an embodiment of the present invention, which will be described in detail below with reference to FIG. 2 .
  • At least one target position of the rotating mirror is acquired in step S11.
  • the externally input target position information includes, but is not limited to, the target position of the rotating parts in the laser radar 20 , the target position pointed to by the laser radar output beam, or the angular deviation of the optical axis of the laser radar 20 .
  • the laser radar 20 also includes a control unit 24, and the target angle of the rotating mirror is obtained after conversion by a processor in the control unit 24.
  • multiple targets 311 need to be set at different distances (or one target 311 should be placed in different orientations sequentially).
  • step S12 according to at least one target position of the rotating mirror 21, the control voltage of the motor 22 is adjusted so that the rotating mirror 21 respectively rotates to the at least one target position; wherein, the control voltage is obtained by combining multiple space vector voltages.
  • the present invention considers the inverter circuit and the motor as a whole based on Space Vector Pulse Width Modulation (SVPWM) technology, the model is simple, and it is convenient for the real-time control of the processor.
  • SVPWM Space Vector Pulse Width Modulation
  • the DC to AC conversion is realized through the inverter circuit, and then a control voltage is synthesized from multiple space vector voltages through an algorithm, and then the brushless motor is controlled to drive the rotating mirror 21 to rotate to the target position.
  • Fig. 3 shows a schematic diagram of the principle of a permanent magnet synchronous motor.
  • the expressions of the three phase voltages (referring to the voltages of point A, point B and point C for the middle connection point N of the three-phase winding of the motor) are as follows:
  • U AN (t) is the voltage of phase A
  • U BN (t) is the voltage of phase B
  • U CN (t) is the voltage of phase C
  • U m is the amplitude of phase voltage
  • ⁇ is the angular velocity of rotation.
  • the three phase voltages are converted into the control voltage U out through the above formula, and its movement trajectory refers to FIG. 4 .
  • the control voltage U out is a rotating voltage vector, which rotates counterclockwise at a constant speed at an angular velocity ⁇ , and the trajectory of the apex is a circle.
  • the control of the three phase voltages is equivalent to the control of the control voltage U out , and the closer the trajectory of U out is to a circle, the closer the three phase voltages are to the three-phase symmetrical sine wave, and the more electromagnetic torque it generates constant.
  • the three phase voltages are equivalent to a control voltage.
  • the motor By adjusting the control voltage of the motor, the motor can run smoothly, and the motor torque output in the specified direction can be obtained to fix the direction of the motor, and then drive the rotating mirror to rotate. to the target location.
  • the following continues to analyze how to realize multiple space vector voltages to synthesize the control voltage through the inverter circuit and algorithm control.
  • FIG. 5A shows a schematic diagram of a three-phase inverter driving circuit according to an embodiment of the present invention.
  • the three-phase inverter drive circuit includes three sets of half bridges with a total of six switch tubes, and each set of half bridges is divided into an upper bridge arm and a lower bridge arm. For example, turning on (shorting) the upper bridge arm of the first group of half bridges, the lower bridge arm of the second group of half bridges, and the lower bridge arm of the third group of half bridges, and disconnecting (opening) the remaining bridge arms can make The current flows from the positive pole of the power supply to the A phase of the motor, then flows through the B phase and C phase, and finally returns to the negative pole of the power supply.
  • the continuous rotation of the motor can be realized by controlling the on-off state of the upper bridge arm and the lower bridge arm and continuously circulating.
  • each bridge arm has two states. Different combinations of the conduction of the upper bridge arm and the conduction of the lower bridge arm correspond to space vector voltages in different directions.
  • the switching values S A , S B , and S C to represent the switching states of the three bridge arms. 1 means the upper bridge arm is on and the lower bridge arm is off, and 0 means the lower bridge arm is on and the upper bridge arm is off.
  • the switch function Sx(x ⁇ a,b,c) is defined as:
  • Figure 5B shows the equivalent circuit diagram of the brushless motor in Figure 5A, that is, when the space vector voltage is U 4 (100) state, the three load resistors are all R, then the load between U dc is:
  • control voltage U out corresponding to other non-zero vectors can be obtained.
  • FIG. 6 a schematic diagram of the space vector voltage in the ABC coordinate system and the ⁇ coordinate system can be obtained as shown in FIG. 6 . It can be seen that the two zero vectors are located at the origin of the coordinate system, and the endpoints of the other six non-zero vectors form a regular hexagon, and divide the plane into six sectors. Using these 6 space vector voltages as base vectors, any vector can be synthesized. In each sector, select two adjacent space voltage vectors to synthesize any voltage vector in each sector according to the principle of volt-second balance , the specific synthetic formula is:
  • U ref is the desired voltage vector
  • T is a pulse width modulation (Pulse Width Modulation, PWM) cycle
  • T x and Ty represent the time occupied by U x and U y in one cycle T.
  • ⁇ -axis direction For example, if it is desired to obtain a resultant vector along the ⁇ -axis direction, firstly, it is determined that the direction is located in the IIth sector, which is determined based on U 2 and U 6 components. Since the ⁇ direction is located in the middle of U 2 and U 6 , U 2 and U 6 are assigned a duty cycle of 50% (regardless of the occupancy time of the zero vector) to obtain the target resultant vector.
  • the laser radar 20 also includes an inverter drive circuit 25, which includes in step S12: adjusting the vector size and/or duty of each space vector voltage in the control voltage Uout ratio, to obtain the motor torque output in the specified direction, so that the rotating mirror 21 reaches the target position.
  • the specific implementation process is as follows: judge the sector where the control voltage U out is located based on the target position; calculate the action time of the adjacent space vector voltage to obtain the PWM duty cycle; determine each bridge of the inverter drive circuit 25 based on the space vector voltage and the duty cycle The switch state and conduction time of the arm; and then control the motor 22 to output the torque in the specified direction, and drive the rotating mirror 21 to reach the target position.
  • a control voltage can be synthesized, and then the motor torque output in a specified direction can be obtained. If the torque vector remains unchanged, the motor 22 can be stopped and point to a fixed direction.
  • step S12 includes: adjusting the control voltage of the motor 22 according to at least one target position and the load information corresponding to the rotating mirror 21, so that the rotating mirror 21 rotates to the at least one target position respectively. That is, based on the above method, keeping the motor torque vector unchanged, the motor 22 can be stopped and point to a fixed direction.
  • the motor 22 drives the rotating mirror 21 to rotate, the rotating mirror 21 is the load of the motor 22 , preferably, the reverse torque is obtained according to the load information corresponding to the rotating mirror 21 . Combined with the reverse torque, the motor torque is slightly adjusted to improve the positioning accuracy of the target position.
  • step S13 the laser radar 20 is calibrated according to the echo pulse information obtained when the rotating mirror is on at least one target position.
  • the calibration method 10 further includes: the laser radar 20 emits detection laser pulses (transmission pulses), and obtains echo pulses from the detection laser pulses emitted to multiple targets 311 (such as reflectors) and, according to the echo pulse information respectively corresponding to the plurality of targets 311 obtained when the rotating mirror 21 is at at least one target position, the calibration parameters of the lidar 20 are determined.
  • the lidar 20 further includes a transmitting unit 26 , a receiving unit 27 and a control unit 24 . Wherein, the transmitting unit 26 transmits detection laser pulses for measuring the distance information between the target object 311 and the laser radar 20 .
  • the receiving unit 27 receives echo pulses of the detection laser pulses reflected by the target object 311 .
  • the control unit 24 obtains the flight time according to the time difference between the detection laser pulse and the echo pulse, obtains the calibration reference quantity according to the echo pulse information, and calibrates the flight time according to the calibration curve, and then calibrates the distance information.
  • the calibration method 10 for example, adopts any one or a combination of the following three ways:
  • a plurality of targets 331 are arranged at different distances, the rotating mirror 21 is controlled to stop at an angular position, and a detection laser pulse is emitted, which is incident on the target 331-1, and the distance of the target 331-1 is obtained. Echo pulse information; remove the target object 331-1, emit a detection laser pulse, and incident the target object 331-2, obtain the echo pulse information of the target object 331-2; and so on, until obtaining the target object 311-n Echo pulse information. According to the actual distance of each target object 311 , the calibration parameters of the laser radar 20 at multiple different distances are determined.
  • a plurality of targets 331 are arranged in multiple orientations, the rotating mirror 21 is controlled to stop at the first angular position, a detection laser pulse is emitted, and the target 331-1 is directly incident, and the target 331 is obtained.
  • -1 echo pulse information control the rotating mirror 21 to stop at the second angular position, emit a detection laser pulse, and directly incident the target object 331-2, obtain the echo pulse information of the target object 331-2; and so on, until the echo pulse information of the target object 311-n is obtained.
  • the calibration parameters of the lidar 20 are determined.
  • a target object 331 is set at the first position, the rotating mirror 21 is controlled to stop at the first angular position, a detection laser pulse is emitted, and the target object 331 is directly incident, and the target object 331 is obtained at the first position
  • the echo pulse information move the target object 331 to the second position, control the rotating mirror 21 to stop at the second angular position, emit the detection laser pulse, hit the target object 331, and obtain the echo of the target object 331 in the second position pulse information; and so on, until the echo pulse information of the target object 311 in the nth position is obtained.
  • the calibration parameters of the lidar 20 are determined.
  • the calibration parameters of the laser radar 20 in multiple directions are determined through statistics (for example, averaging the errors at the same distance, etc.).
  • the calibration parameter can be an error information table (look up table according to the distance) or an error function (obtained by fitting according to the calibration data, and the error can be calculated based on the distance to correct the measured value).
  • the echo pulse information includes at least one of the leading edge, pulse width, slope, and peak value of the echo pulse
  • the calibration method 10 further includes: based on the calibration calibration parameters, by adjusting the calibration calibration parameters The data is calculated and processed, and the calibration table of the lidar 20 is established.
  • the leading edge slope value, pulse width, slope and peak value of the echo pulse are all reference quantities that change monotonically with the intensity of the echo pulse within the measurement range, and the time-of-flight of the laser radar 20 is calibrated based on these information , such as forming a correspondence table by means of interpolation, fitting or approximation, to calibrate the receiving time of the echo pulse, so as to realize the calibration of the flight time, and then obtain more accurate distance information.
  • the goal of calibration is to reduce the error value of the leading edge time of the echo pulse, that is, the value that needs to be increased or decreased to obtain the leading edge time.
  • the triggering time of transmitting the detection laser pulse it is used as the transmitting time;
  • the echo signal threshold the rising edge time of the echo pulse is extracted as the receiving time; and then the flight time is obtained according to the time difference between the transmitting time and the receiving time.
  • the error information is determined based on the distance between the time-of-flight and the target object 311, and then a calibration table is established.
  • the goal of calibration is to calibrate the peak time of the echo pulse.
  • the triggering time of transmitting the detection laser pulse it is regarded as the transmitting time;
  • the time of the peak value of the echo signal it is regarded as the receiving time.
  • the flight time is obtained according to the time difference between the transmission time and the reception time;
  • the error information is determined based on the distance between the flight time and the target object 311, and then a calibration table is established.
  • the plurality of targets 311 may respectively correspond to different measurement information, and the calibration parameters are used to calibrate the corresponding measurement information.
  • the measurement information is, for example, the distance and/or reflectivity of the target. Select different measurement information according to requirements, compare the measured value with the actual value of the target object 311, determine the error information, form the calibration calibration parameters, and then establish the calibration calibration table of the laser radar 10, all of which are within the protection scope of the present invention Inside.
  • one or more targets 311 have different reflectivities.
  • the multiple targets 311 set during the calibration process are, for example, target plates with different reflectivities; when there is only one target 311 , for example, the reflectivity can be adjusted by replacing the sticker on the target plate.
  • the rotating mirror 21 is controlled to stop at at least one angular position in sequence, the reflectivity of the target object 311 is obtained based on the echo pulse information, and the error information is determined based on the measured value and the reflectivity of the target object 311 , and then establish the calibration calibration table of reflectivity.
  • the calibration method 10 is implemented through steps S11-S13 as follows: after obtaining the target position information of the rotating mirror 21, the control voltage U out is adjusted by controlling the switch state and conduction time of each bridge arm of the inverter drive circuit 25 The vector size and duty cycle of multiple space vector voltages in the space vector voltage, so as to realize the control motor 22 to drive the rotating mirror 21 to rotate to the target position; then the laser radar 20 emits a detection laser pulse to obtain the echo pulse information on the target object 311-1 , then change the orientation of the target object 311-1 or repeat the above steps for the next target object 311-2, and determine the measurement information (such as distance and/or reflectivity) with the laser radar 20 based on the obtained multiple sets of echo pulse information Corresponding calibration calibration parameters, and then establish a calibration calibration table. When the laser radar is working, accurate measurement results can be obtained according to the measurement information and the corresponding calibration table.
  • the inverter driving circuit 25 may be three-phase, five-phase or nine-phase, all of which are within the protection scope of the present invention.
  • the present invention can also combine proportional integral derivative (Proportional Integral Derivative, PID) control technology, so that the rotating mirror 21 can be stabilized at the target position as soon as possible.
  • PID Proportional Integral Derivative
  • the working principle of the PID controller is: set an output target value, the feedback system returns the output value, if it is inconsistent with the target value, there is an error, and adjust the input value according to this error until the output reaches the target value.
  • Figure 8 shows the overall block diagram of the PID controller. After the output value of the system is obtained through the measuring element, the output value of the feedback is superimposed on the input through one or more of the three operation modes of proportional, integral, and differential, so that The output value of the control actuator reaches the target value.
  • step S12 further includes: during the rotation of the motor 22, acquiring the deviation position information of the rotating mirror 21, and adjusting the control voltage according to the deviation position information until the rotating mirror 21 reaches the target position.
  • the deviation position information is acquired according to the current position and the target position of the rotating mirror 21 .
  • the control unit 24 includes a PID controller, which measures the current position of the rotating mirror 21 through the position sensor 23, feeds back to the input terminal of the PID control module, obtains the deviation from the input target position information, and adjusts the ratio, integral and sum based on the deviation.
  • the control voltage is adjusted in a differential manner until the rotating mirror 21 rotates to the target position. This process can be repeated continuously to automatically and quickly fix the rotating mirror 21 to the target position.
  • the lidar 20 further includes a code disc 23 , which is a position sensor, and is used to detect the position of the rotating mirror 21 .
  • the calibration method 10 further includes: detecting the current position of the rotating mirror 21 through the code disc 23 .
  • PID controller for automatic closed-loop control of the motor.
  • three PID controllers may be used, from the inner loop to the outer loop: current loop, speed loop and position loop. That is, the current (torque) of the motor is controlled by current feedback, then the rotational speed of the motor is controlled by controlling the torque, and finally the position of the motor is controlled by controlling the rotational speed of the motor.
  • step S12 also includes: during the rotation process of the motor 22, obtaining the current circuit parameter information, adjusting the control voltage U out according to the deviation position information and the circuit parameter information until the rotating mirror 21 reaches the target position .
  • the angle of the rotating mirror 21 so that the outgoing light points to the target 311 directly in front, through the aforementioned space vector voltage control, combined with the position information on the encoder disk 23, through the closed-loop PID controller, that is The swivel mirror 21 can be made to point and locked at a desired angle.
  • Fig. 9 shows the PID control schematic diagram of an embodiment of the present invention, wherein, the control unit 24 includes a PID control module, the current position information can be obtained based on the position sensor 23 (such as a photoelectric sensor on the code disc), and the circuit parameter information can be obtained according to the output of the motor 22 .
  • the circuit parameter information is determined according to the current information of the motor 22 .
  • the current information is used to determine the current power of the motor 22, and when the rotating mirror 21 is close to the target position, the current is reduced to reduce the power of the motor 22 to rotate. Therefore, input current information to the current loop of the PID control module, input current position information, such as angle position information, to the position loop in the PID control module, and then calculate with the target position information, the motor 22 can be driven to rotate through feedback control. Mirror 21 is turned to this target angle.
  • the control unit 24 includes a PID control module and a space vector voltage control module.
  • the target position information of the rotating mirror 21 input from the outside is received.
  • the obtained deviation position information is converted into the target current through the position loop in the PID control module.
  • the output phase current of the motor 22 is sampled, and the current loop in the PID control module receives
  • the target current and the phase current output by the motor 22 are converted into a target voltage after the coordinate system conversion, and output to the space vector voltage control module.
  • it is converted into the control voltage U out by the space vector voltage control module, so as to control the driving circuit 25 to output the three-phase voltage of the three-phase winding coordinate system.
  • the above-mentioned process can be completed by the controller 24 and the inverter driving circuit 25 of the motor 22, so that after the radar product is produced, the motor 22 can be directly controlled to drive the rotating mirror 21 to fix to the target angle without disassembly. After the radar outgoing beam angle is fixed, the current beam echo signal information can be quickly obtained according to the real distance of the target object 311, so as to obtain parameters such as distance calibration and reflectance calibration.
  • the invention also relates to a computer-readable storage medium comprising computer-executable instructions stored thereon, wherein said executable instructions, when executed by a processor, implement the calibration method 10 as described above.
  • the present invention also relates to a laser radar 20, referring to FIG. 2 , including a rotating mirror 21 and a motor 22 that drives the rotating mirror to rotate, wherein the laser radar 20 also includes:
  • a position sensor 23 configured to detect the position information of the rotating mirror 21
  • the control unit 24, coupled with the motor 22 and the position sensor 23, is configured as:
  • the control voltage U out of the motor 22 adjusts the control voltage U out of the motor 22, so that the rotating mirror 21 rotates to the at least one target position respectively; wherein, the control voltage U out adopts a plurality of space vector voltages obtained synthetically;
  • the position sensor 23 is an encoder disc, and the position information is an angular position.
  • the lidar 20 further includes a multi-phase inverter drive circuit 25, the multi-phase inverter drive circuit 25 is coupled between the control unit 24 and the motor 22, configured It works to drive the motor 22 under the control of the control unit 24 .
  • the multi-phase inverter drive circuit 25 can be selected to be three-phase, five-phase or nine-phase.
  • the control voltage U out is synthesized using a part of multiple space vector voltages. That is, the control voltage U out may select all of the plurality of space vector voltages to be combined, or may select a part of them to be combined.
  • the plane coordinate system is divided into multiple sectors based on multiple basic space vector voltages, and several space vector voltages are selected from the multiple basic space vector voltages for synthesis according to the sector where the control voltage U out is located.
  • the multi-phase inverter drive circuit 25 is a three-phase inverter drive circuit
  • the multiple space vector voltages are six space vector voltages
  • a part of the multiple space vector voltages are two space vector voltages.
  • the plane coordinate system is divided into six sectors based on six basic space vector voltages, and two adjacent two of the six basic space vector voltages are selected for synthesis according to the sector where the control voltage U out is located.
  • control unit 24 adjusts the vector size and/or duty cycle of each space vector voltage in the control voltage U out to obtain the motor torque output in a specified direction to control the motor Stalls and points in a fixed direction.
  • the control unit 24 obtains the deviation position information of the rotating mirror 21, and adjusts the control voltage U out according to the deviation position information until The rotating mirror 21 reaches the target position.
  • the control unit 24 acquires current circuit parameter information, and adjusts the control voltage U out according to the deviation position information and the circuit parameter information , until the rotating mirror 21 reaches the target position.
  • the present invention also includes a transmitting unit 26 and a receiving unit 27, wherein the transmitting unit 26 is configured to transmit a detection laser pulse, and the receiving unit 27 is configured to obtain the detection laser pulse to be emitted to a plurality of targets 311, the control unit 24 is further configured to determine the Calibration calibration parameters of the lidar 20 .
  • the plurality of targets 311 may respectively have different distances and/or reflectances.
  • the echo pulse information includes at least one of the front edge, pulse width, slope and peak value of the echo pulse, and the control unit 24 based on the calibration parameters, by The data of the calibration calibration parameters are calculated and processed to establish the calibration calibration table of the lidar 20 .
  • the lidar further includes a computer-readable storage medium including computer-executable instructions stored thereon, and the executable instructions implement the calibration when executed by the control unit 24 Method 10.
  • the present invention also relates to a calibration system 30, referring to FIG. 1A, comprising:
  • an alignment aid 31 comprising at least one target 311 arranged in different orientations
  • Laser radar 20 described laser radar 20 comprises rotating mirror 21 and the motor 22 that drives described rotating mirror 21 to rotate, and described laser radar 20 also comprises:
  • the position sensor 23 is configured to detect the position information of the rotating mirror 21; and the control unit 24 is coupled to the motor 22 and the position sensor 23 and is configured to:
  • the control voltage of the motor 22 adjusts the control voltage of the motor 22, so that the rotating mirror 21 respectively rotates to the at least one target position; wherein, the control voltage is obtained by combining multiple space vector voltages;
  • the at least one target position corresponds to the at least one target object 311 arranged in different orientations.

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Abstract

本发明提供一种激光雷达的校准方法，其中，所述激光雷达包括转镜和驱动所述转镜旋转的电机，所述校准方法包括：S11：获取所述转镜的至少一个目标位置；S12：根据所述至少一个目标位置，调节所述电机的控制电压，以使得所述转镜分别旋转至所述至少一个目标位置；其中，所述控制电压采用多个空间矢量电压合成获得；和S13：根据所述转镜在所述至少一个目标位置上时，获得的回波脉冲信息对所述激光雷达进行校准。本发明的技术方案可实现控制电机停在指定位置，能够提供更加高效和精准的电机控制方式，对于未在工作状态的电机也能准确地进行角度控制，提高了校准操作的效率。

Description

激光雷达的校准方法、激光雷达以及校准系统 技术领域
本公开涉及光电探测领域，尤其涉及一种激光雷达的校准方法、一种计算机可读存储介质、一种激光雷达以及一种校准系统。
背景技术
现有的带有转镜的机械激光雷达校准方式(如距离校准、反射率校准)中，是在激光雷达尚未完成外壳装配的时候进行校准，通过机械工装，固定激光雷达中的旋转部件，从而固定激光雷达出射光束的指向，进而能够在校准过程中保持产品姿态稳定以及激光雷达回波信号的稳定。具体校准方式为在一个或多个固定距离设置不同反射率的目标板，使得激光雷达旋转，将激光出射方向指向不同的目标板，通过测量回波的脉宽及前沿，建立脉宽、前沿以及真实距离之间的对应关系，从而完成激光雷达校准。
由于电机本身不能锁定自身方向，校准过程中需要外部工装的辅助来固定角度，避免转镜晃动，影响校准结果。为了安装外部工装，激光雷达外壳先不装配，在完成校准之后需要进一步实现外壳装配等生产环节。在校准过程中目标板距离激光雷达较远，会显著占用生产场地空间，由于激光雷达通常在超净间内完成生产，空间资源较为宝贵，上述校准方式对于生产线的布置有显著的不利影响。
除通过机械工装固定外，还可以通过控制电机来固定激光雷达的转镜角度。传统的电机控制方法是从电源的角度出发，生成一个可调频调压的正弦波电源。为了使电机的转子连续旋转，需要在其内部(或外部的驱动电路)进行直流转交流的过程。对于有刷电机，通过电刷和换向器实现，而对于无刷电机则是通过逆变电路实现。其中，无刷电机包括无刷直流电机(Brushless Direct Current Motor,BLDCM)和永磁同步电机(Permanent Magnet Synchronous Motor，PMSM)。以三相二极永磁同步电机为例，永磁同步电机PMSM的转子是永磁体，定子上有三相绕组，采用Y型接法呈对称分布，在空间上互差120°，构成永磁同步电机PMSM的三相静止坐标系ABC。其工作原理为：在定子中产生一个大小恒定的旋转磁场，以带动转子连续旋转。为了保证电机的运动性能平稳，这个旋转磁场的大小是恒定的。但是，对三个相电压分别进行控制的难度较大，急需一种高效且精准的控制方案以实现对电机的有效控制。
背景技术部分的内容仅仅是公开发明人所知晓的技术，并不当然代表本领域的现有技术。
发明内容
有鉴于现有技术的一个或多个缺陷，本发明涉及一种激光雷达的校准方法，其中，所述激光雷达包括转镜和驱动所述转镜旋转的电机，所述校准方法包括：
S11：获取所述转镜的至少一个目标位置；
S12：根据所述至少一个目标位置，调节所述电机的控制电压，以使得所述转镜分别旋转至所述至少一个目标位置；其中，所述控制电压采用多个空间矢量电压合成获得；和
S13：根据所述转镜在所述至少一个目标位置上时，获得的回波脉冲信息对所述激光雷达进行校准。
根据本发明的一个方面，所述步骤S12包括：调节所述控制电压中的各个空间矢量电压的矢量大小和/或占空比，获得指定方向的电机力矩输出，以使得所述转镜到达所述目标位置。
根据本发明的一个方面，所述步骤S12包括：根据所述至少一个目标位置以及所述转镜对应的负载信息，调节所述电机的控制电压，以使得所述转镜分别旋转至所述至少一个目标位置。
根据本发明的一个方面，根据所述转镜的负载信息获取反向力矩，矫正电机力矩输出。
根据本发明的一个方面，所述步骤S12还包括：在所述电机的转动过程中，获取所述转镜的偏差位置信息，根据所述偏差位置信息调节所述控制电压，直至所述转镜到达所述目标位置。
根据本发明的一个方面，根据所述转镜的当前位置和目标位置获取所述偏差位置信息。
根据本发明的一个方面，步骤S12还包括：在所述电机的转动过程中，获取当前的电路参数信息，根据所述偏差位置信息以及所述电路参数信息调节所述控制电压，直至所述转镜到达目标位置。
根据本发明的一个方面，根据所述电机的电流信息确定所述电路参数信息。
根据本发明的一个方面，所述激光雷达还包括编码盘，所述校准方法还包括：通过所述编码盘检测所述转镜的当前位置。
根据本发明的一个方面，所述校准方法还包括：所述激光雷达发射探测激光脉冲，并获取所述探测激光脉冲出射至多个目标物上的回波脉冲；并且，根据所述转镜在所述至少一个目标位置上时获得的、与多个目标物分别对应的回波脉冲信息，确定所述激光雷达的校准标定参数。
根据本发明的一个方面，所述多个目标物可分别对应不同的测量信息，所述校准标定参数用于标定相应的测量信息。
根据本发明的一个方面，所述回波脉冲信息包括所述回波脉冲的前沿、脉宽、坡 度和峰值中的至少一项，所述校准方法还包括：基于所述校准标定参数，通过对所述校准标定参数的数据进行计算处理，建立所述激光雷达的校准标定表。
本发明还涉及一种计算机可读存储介质,包括存储于其上的计算机可执行指令，其中，所述可执行指令在被处理器执行时实施如上所述的校准方法。
本发明还涉及一种激光雷达，包括转镜和驱动所述转镜旋转的电机，其中，所述激光雷达还包括：
位置传感器，配置为检测所述转镜的位置信息；和
控制单元，与所述电机和所述位置传感器耦接，配置为：
通过所述位置传感器获取所述转镜的至少一个目标位置；
根据所述至少一个目标位置，调节所述电机的控制电压，以使得所述转镜分别旋转至所述至少一个目标位置；其中，所述控制电压采用多个空间矢量电压合成获得；和
获取当所述转镜在所述至少一个目标位置上时的回波脉冲信息，以对所述激光雷达进行校准。
根据本发明的一个方面，所述位置传感器为编码盘，所述位置信息为角度位置。
根据本发明的一个方面，所述激光雷达还包括多相逆变驱动电路，所述多相逆变驱动电路耦接于所述控制单元与所述电机之间，配置为在所述控制单元的控制下驱动所述电机工作。
根据本发明的一个方面，所述控制电压采用所述多个空间矢量电压中的一部分进行合成。
根据本发明的一个方面，所述多相逆变驱动电路为三相逆变驱动电路，所述多个空间矢量电压为六个空间矢量电压，所述多个空间矢量电压中的一部分为两个空间矢量电压。
根据本发明的一个方面，所述控制单元通过控制所述多项逆变驱动电路的开关状态和持续时间，以调节所述控制电压中的各个空间矢量电压的矢量大小和/或占空比，获得指定方向的电机力矩输出，以控制所述电机停转并指向固定方向。
根据本发明的一个方面，在所述电机的转动过程中，所述控制单元获取所述转镜的偏差位置信息，根据所述偏差位置信息调节所述控制电压，直至所述转镜到达所述目标位置。
根据本发明的一个方面，在所述电机的转动过程中，所述控制单元获取当前的电路参数信息，根据所述偏差位置信息以及所述电路参数信息调节所述控制电压，直至所述转镜到达目标位置。
根据本发明的一个方面，还包括发射单元和接收单元，其中所述发射单元配置为发射探测激光脉冲，所述接收单元配置为获取所述探测激光脉冲出射至多个目标物上的回波脉冲，所述控制单元还配置为根据所述转镜在所述至少一个目标位置上时获得 的、与多个目标物分别对应的回波脉冲信息，确定所述激光雷达的校准标定参数。
根据本发明的一个方面，所述多个目标物可分别具有不同的距离和/或反射率。
根据本发明的一个方面，所述回波脉冲信息包括所述回波脉冲的前沿、脉宽、坡度和峰值中的至少一项，所述控制单元基于所述校准标定参数，通过对所述校准标定参数的数据进行计算处理，建立所述激光雷达的校准标定表。
根据本发明的一个方面，所述激光雷达还包括计算机可读存储介质,包括存储于其上的计算机可执行指令，所述可执行指令在被所述控制单元执行时实施如上所述的校准方法。
本发明还涉及一种校准系统，包括：
校准辅助装置，所述校准辅助装置包括至少一个设置在不同方位的目标物；和
激光雷达，所述激光雷达包括转镜和驱动所述转镜旋转的电机，所述激光雷达还包括：
位置传感器，配置为检测所述转镜的位置信息；和
控制单元，与所述电机和所述位置传感器耦接，配置为：
通过所述位置传感器获取所述转镜的至少一个目标位置；
根据所述至少一个目标位置，调节所述电机的控制电压，以使得所述转镜分别旋转至所述至少一个目标位置；其中，所述控制电压采用多个空间矢量电压合成获得；和
获取当所述转镜在所述至少一个目标位置上时的回波脉冲信息，以对所述激光雷达进行校准。
其中，所述至少一个目标位置与所述至少一个设置在不同方位的目标物相对应。
对于转镜扫描雷达，在校准过程中需要固定出射光方向，由于电机自由转动，校准过程不能在生产过程完成后进行，必须在生产过程中，外壳没有装配的时候进行校准，严重影响生产效率以及产品生产良率控制。本发明利用空间矢量电压调制技术及相应的逆变驱动电路，实现电机可以停在指定的角度上，从而固定激光雷达出射光指向，从而提供更加高效和精准的电机控制方式，对于未在工作状态的电机也能准确地进行角度控制，提高了校准操作的效率。本发明通过结合较为先进的电机驱动算法与激光雷达校准技术，实现了激光雷达硬件生产与校准参数的分离，由于校准过程通常需要占用较大的空间，本发明可以避免硬件生产过程中所需的超净间空间被校准过程占用，从而提高了空间利用率，提高生产效率，优化生产环节，有助于降低雷达生产成本。
附图说明
构成本公开的一部分的附图用来提供对本公开的进一步理解，本公开的示意性实施例及其说明用于解释本公开，并不构成对本公开的不当限定。在附图中：
图1A示出了本发明一个实施例的激光雷达校准示意图；
图1B示出了激光雷达的扫描单元的示意图；
图2示出了本发明一个实施例的激光雷达校准方法流程图；
图3示出了一种永磁同步电机的原理图；
图4示出了本发明一个实施例的相电压转化成控制电压矢量的轨迹图；
图5A示出了本发明一个实施例的三相逆变驱动电路的原理图；
图5B示出了图5A在基本电压空间矢量U 4(100)状态的等效电路图；
图6示出了本发明一个实施例的空间矢量电压在ABC坐标系和αβ坐标系中的示意图；
图7A示出了本发明一个实施例的激光雷达校准示意图；
图7B示出了本发明一个实施例的激光雷达校准示意图；
图7C示出了本发明一个实施例的激光雷达校准示意图；
图8示出了PID控制器的整体框图；
图9示出了本发明一个实施例的PID控制示意图。
具体实施方式
在下文中，仅简单地描述了某些示例性实施例。正如本领域技术人员可认识到的那样，在不脱离本发明的精神或范围的情况下，可通过各种不同方式修改所描述的实施例。因此，附图和描述被认为本质上是示例性的而非限制性的。
在本发明的描述中，需要理解的是，术语"中心"、"纵向"、"横向"、"长度"、"宽度"、"厚度"、"上"、"下"、"前"、"后"、"左"、"右"、"竖直"、"水平"、"顶"、"底"、"内"、"外"、"顺时针"、"逆时针"等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本发明和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本发明的限制。此外，术语"第一"、"第二"仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有"第一"、"第二"的特征可以明示或者隐含地包括一个或者更多个所述特征。在本发明的描述中，"多个"的含义是两个或两个以上，除非另有明确具体的限定。
在本发明的描述中，需要说明的是，除非另有明确的规定和限定，术语"安装"、"相连"、"连接"应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接:可以是机械连接，也可以是电连接或可以相互通讯；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通或两个元件的相互作用关系。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本发明中的具体含义。
在本发明中，除非另有明确的规定和限定，第一特征在第二特征之"上"或之"下" 可以包括第一和第二特征直接接触，也可以包括第一和第二特征不是直接接触而是通过它们之间的另外的特征接触。而且，第一特征在第二特征"之上"、"上方"和"上面"包括第一特征在第二特征正上方和斜上方，或仅仅表示第一特征水平高度高于第二特征。第一特征在第二特征"之下"、"下方"和"下面"包括第一特征在第二特征正上方和斜上方，或仅仅表示第一特征水平高度小于第二特征。
下文的公开提供了许多不同的实施方式或例子用来实现本发明的不同结构。为了简化本发明的公开，下文中对特定例子的部件和设置进行描述。当然，它们仅仅为示例，并且目的不在于限制本发明。此外，本发明可以在不同例子中重复参考数字和/或参考字母，这种重复是为了简化和清楚的目的，其本身不指示所讨论各种实施方式和/或设置之间的关系。此外，本发明提供了的各种特定的工艺和材料的例子，但是本领域普通技术人员可以意识到其他工艺的应用和/或其他材料的使用。
以下结合附图对本发明的优选实施例进行说明，应当理解，此处所描述的优选实施例仅用于说明和解释本发明，并不用于限定本发明。
图1A示出了激光雷达的校准示意图，图1B示出了激光雷达的扫描单元的示意图。如图1A和1B所示，激光雷达20包括转镜21和驱动转镜21旋转的电机22，二者构成激光雷达20的扫描单元。如图1B所示，转镜21具有旋转轴O，可绕旋转轴O进行旋转和/或往复摆动。转镜21上具有反射面，其上接收激光雷达20的激光器发射出的激光束L，并将激光束R反射到激光雷达外部的三维空间中。随着转镜21围绕旋转轴O旋转，反射面将会把激光束L沿着不同的方向反射，在三维空间中可以覆盖一定的范围，构成激光雷达20的视场FOV。另外，转镜21可包括一个或多个转轴O，例如包括水平方向的扫描转轴和竖直方向的扫描转轴，这些都在本发明的范围内。另外，激光雷达20还包括控制单元24，用于控制电机21的旋转。如图1A所示，当校准激光雷达20时，在激光雷达周围的不同方位(不同角度和/或不同位置)处设置多个目标物311，如图1A所示的目标物311-1、目标物311-2、……以及目标物311-n，控制电机24的旋转，将激光出射方向指向不同的目标板，通过测量回波的脉宽及前沿，建立脉宽、前沿以及真实距离之间的对应关系，从而完成激光雷达校准。
图2示出了本发明一个实施例的激光雷达的校准方法10的流程图，下面参考图2详细描述。
在步骤S11中获取转镜的至少一个目标位置。例如外部输入的目标位置信息，其形式包括但不限于激光雷达20中的旋转部件的目标位置、激光雷达出射光束指向的目标位置、或者激光雷达20的光轴的角度偏差。激光雷达20还包括控制单元24，通过控制单元24内的处理器换算后得到转镜的目标角度。对于激光雷达20的校准，如图1A所示，需要在不同距离设置多个目标物311(或者将一个目标物311依次放置在不同的方位)。在校准过程中，需要控制转镜21的角度，使得转镜21停在多个目标位置，使得出射激光束依次入射到不同的目标物311(例如反射板)上，且出射光与板 面垂直(正入射)。在每个角度下，都需要收集回波信息。
在步骤S12中根据转镜21的至少一个目标位置，调节电机22的控制电压，以使得转镜21分别旋转至所述至少一个目标位置；其中，控制电压采用多个空间矢量电压合成获得。
本发明基于空间矢量脉冲宽度调制(Space Vector Pulse Width Modulation，SVPWM)技术将逆变电路和电机看做一个整体来考虑，模型简单，便于处理器的实时控制。根据本发明的一个优选实施例，通过逆变电路实现直流到交流的转换，然后通过算法实现由多个空间矢量电压合成一个控制电压，进而实现控制无刷电机驱动转镜21旋转至目标位置。
图3示出了一种永磁同步电机的原理示意图。三个相电压(指A点、B点和C点对于电机三相绕组的中间连接点N的电压)的表达式如下：
U AN(t)＝U mcosωt
Figure PCTCN2022099753-appb-000001
Figure PCTCN2022099753-appb-000002
其中，U AN(t)为A相电压，U BN(t)为B相电压，U CN(t)为C相电压，U m为相电压幅值，ω为旋转的角速度。将三个相电压进行合成，合成关系式如下：
Figure PCTCN2022099753-appb-000003
通过上式将三个相电压转化成控制电压U out，其运动轨迹参考图4。由图4可见，控制电压U out是一个旋转电压矢量，以角速度ω逆时针匀速旋转，顶点运动轨迹为一个圆。这意味着对三个相电压的控制等效于对控制电压U out的控制，并且U out的轨迹越接近圆，三个相电压就越接近三相对称正弦波，其产生的电磁转矩越恒定。
通过上述分析，将三个相电压等效为一个控制电压，通过调节电机的该控制电压既可以实现电机平稳运行，又可以获得指定方向的电机力矩输出以固定电机方向，进而实现驱动转镜旋转到目标位置。以下继续分析如何通过逆变电路及算法控制实现多个空间矢量电压合成该控制电压。
图5A示出了本发明一个实施例的三相逆变驱动电路的原理图。其中，三相逆变驱动电路包括三组半桥共六个开关管，每组半桥分为上桥臂和下桥臂。例如，导通(短路)第一组半桥的上桥臂、第二组半桥的下桥臂以及第三组半桥的下桥臂，断开(断路)其余的桥臂，就可以让电流从电源正极先流过电机的A相，再流经B相和C相，最后回到电源负极。控制上桥臂与下桥臂的开断状态并不断循环，即可实现电机的连续旋转。
同一组半桥的两个开关管不能同时打开或者关闭，因此每个桥臂都存在两种状态。上桥臂导通与下桥臂导通的不同组合，对应着不同方向的空间矢量电压。定义开关量 S A、S B、S C表示三个桥臂的开关状态，用1表示上桥臂导通下桥臂关断，0表示下桥臂导通上桥臂关断。为了简化表示，定义开关函数Sx(x∈a,b,c)为：
Figure PCTCN2022099753-appb-000004
根据排列组合，开关函数共有2 3＝8种组合，这8种组合被称为基本的空间矢量电压，包括6个非零矢量：U 1(001)、U 2(010)、U 3(011)、U 4(100)、U 5(101)、U 6(110)，以及2个零矢量：U 0(000)、U 7(111)。
图5B示出了图5A中无刷电机的等效电路图，即空间矢量电压为U 4(100)状态时，三个负载电阻均为R，则U dc间的负载为：
Figure PCTCN2022099753-appb-000005
从各电阻的分压情况可以得出三个相电压如下：
Figure PCTCN2022099753-appb-000006
Figure PCTCN2022099753-appb-000007
此处U BN与U CN的合矢量大小仍为1/3U dc，且方向与U AN相反。合成后的控制电压U out＝U dc。
同理可得出其它非零矢量对应的控制电压U out。
将上述8个空间矢量电压画在坐标轴中，可以得到如图6所示的空间矢量电压在ABC坐标系和αβ坐标系中的示意图。可以看出，2个零矢量位于坐标系原点，其余6个非零矢量的端点组成了一个正六边形，同时把平面划分为6个扇区。将这6个空间矢量电压作为基向量，即可合成任意矢量，在每一个扇区，选择相邻两个空间电压矢量，即可根据伏秒平衡原则，合成每个扇区内的任意电压矢量，具体合成的公式为：
Figure PCTCN2022099753-appb-000008
其中，U ref是期望得到的电压矢量，T是一个脉冲宽度调制(Pulse Width Modulation，PWM)周期，T x和T y表示在一个周期T中U x和U y所占的时间。
其中，
Figure PCTCN2022099753-appb-000009
代表两个零矢量，可以是U 0也可以是U 7，零矢量的选择比较灵活，通过合理地配置零矢量占用的时间
Figure PCTCN2022099753-appb-000010
可以让空间矢量电压的切换更平顺。此处U y与U y作为基向量，具体代表6个空间电压矢量U 1、U 2、U 3、U 4、U 5、U 6中的哪两个，取决于转子旋转到的扇区，例如旋转到Ⅲ号扇区，则U x与U y所表示的基矢量为U 2与U 3。设电机的转速为ω，则电机旋转一圈的周期为1/ω,由于有六个扇区，所以一个扇区内的PWM周期T＝1/6*1/ω＝1/6ω。
举例而言，如果想要得到一个沿着β轴方向的合矢量，首先确定该方向位于第I I 扇区中，该扇区基于U 2和U 6分量来确定。由于β方向位于U 2和U 6的中间，因此，U 2和U 6被分别分配50％的占空比(不考虑零矢量的占用时间的话)，来得到目标合矢量。
通过上述分析，电机中存在一个电压矢量U ref表征的电压，根据右手螺旋定理，可以判断出磁场的磁力线方向，和电压矢量U ref一致。由于转子永磁体会努力旋转到内部磁力线和外部磁场方向一致，所以这个矢量就可以表征希望转子旋转到的方向，亦即通过6个空间矢量电压合成的控制电压U out。因为本发明通过控制U out实现固定电机方向，无需考虑变换方向时平顺切换的问题，所以合成控制电压U out时可以不考虑零矢量。
根据本发明的一个优选实施例，如图2所示，激光雷达20还包括逆变驱动电路25，在步骤S12包括：调节控制电压U out中的各个空间矢量电压的矢量大小和/或占空比，获得指定方向的电机力矩输出，以使得转镜21到达所述目标位置。具体实现流程为：基于目标位置判断控制电压U out所在扇区；计算相邻空间矢量电压的作用时间，得到PWM占空比；基于空间矢量电压和占空比确定逆变驱动电路25的各桥臂的开关状态和导通时间；进而控制电机22输出指定方向的力矩，驱动转镜21到达目标位置。亦即，基于以上方法，只要在逆变电路驱动电机22的过程中，合理组合6个矢量大小及其占空比，即可合成一个控制电压，进而获得指定方向的电机力矩输出，如果保持电机力矩矢量不变，即可让电机22停转并指向固定方向。
根据本发明的一个优选实施例，在步骤S12包括：根据至少一个目标位置以及转镜21对应的负载信息，调节电机22的控制电压，以使得转镜21分别旋转至所述至少一个目标位置。亦即，基于以上方法，保持电机力矩矢量不变，即可让电机22停转并指向固定方向。当电机22驱动转镜21旋转时，转镜21即为电机22的负载，优选地，根据转镜21对应的负载信息获取反向力矩。结合该反向力矩对电机力矩略作调整，以提高目标位置的定位精度。
在步骤S13中根据转镜在至少一个目标位置上时，获得的回波脉冲信息对激光雷达20进行校准。
根据本发明的一个优选实施例，所述校准方法10还包括：激光雷达20发射探测激光脉冲(发射脉冲)，并获取探测激光脉冲出射至多个目标物311(例如反射板)上的回波脉冲；并且，根据转镜21在至少一个目标位置上时获得的、与多个目标物311分别对应的回波脉冲信息，确定激光雷达20的校准标定参数。参考图1A、图1B和图2，激光雷达20还包括发射单元26、接收单元27和控制单元24。其中，发射单元26发射探测激光脉冲，用以测量目标物311与激光雷达20的距离信息。接收单元27接收该探测激光脉冲被目标物311反射的回波脉冲。控制单元24根据探测激光脉冲与回波脉冲的时间差获取飞行时间，根据回波脉冲信息获取校准参考量，并根据校准曲线对飞行时间进行校准，进而校准距离信息。
具体地，校准方法10例如采用以下三种方式中的任一种或多种的结合：
1)如图7A所示，多个目标物331设置在不同距离处，控制转镜21停在一个角度位置上，发射探测激光脉冲，正入射目标物331-1，获得目标物331-1的回波脉冲信息；移开目标物331-1，发射探测激光脉冲，正入射目标物331-2，获得目标物331-2的回波脉冲信息；依此类推，直至获得目标物311-n的回波脉冲信息。根据每个目标物311的实际距离，确定该激光雷达20在多个不同距离的校准标定参数。
2)如图7B所示，多个目标物331设置在多个方位上，控制转镜21停在第一个角度位置上，发射探测激光脉冲，正入射目标物331-1，获得目标物331-1的回波脉冲信息；控制转镜21停在第二个角度位置上，发射探测激光脉冲，正入射目标物331-2，获得目标物331-2的回波脉冲信息；依此类推，直至获得目标物311-n的回波脉冲信息。根据每个方位的实际距离，确定该激光雷达20在多个不同距离的校准标定参数。
3)如图7C所示，一个目标物331设置在第一方位，控制转镜21停在第一个角度位置上，发射探测激光脉冲，正入射目标物331，获得目标物331在第一方位的回波脉冲信息；移动目标物331至第二方位，控制转镜21停在第二个角度位置上，发射探测激光脉冲，正入射目标物331，获得目标物331在第二方位的回波脉冲信息；依此类推，直至获得目标物311在第n方位上的回波脉冲信息。根据每个方位的实际距离，确定该激光雷达20在多个不同距离的校准标定参数。
以上述三种方式为例，通过统计(例如对同一距离的误差求平均等)确定激光雷达20在多个方位上的校准标定参数。其中，校准标定参数可以为误差信息表(根据距离查表)或者误差函数(根据校准数据拟合得到，可以基于距离计算误差以对测量值进行校正)。
根据本发明的一个优选实施例，回波脉冲信息包括回波脉冲的前沿、脉宽、坡度和峰值中的至少一项，所述校准方法10还包括：基于校准标定参数，通过对校准标定参数的数据进行计算处理，建立所述激光雷达20的校准标定表。其中，回波脉冲的前沿斜率值、脉宽、坡度以及峰值均是在测程范围内随着回波脉冲的强度改变而单调变化的参考量，基于这些信息对激光雷达20的飞行时间进行校准，例如通过插值、拟合或逼近等方式形成对应表，对回波脉冲的接收时刻进行校准，从而实现对飞行时间的校准，进而可以得到更为精准的距离信息。
以前沿法为例，校准的目标是减小回波脉冲的前沿时间的误差值，亦即，测量得到前沿时间需要增减的数值。根据发射探测激光脉冲的触发时刻，作为发射时刻；根据回波信号阈值提取回波脉冲的上升沿时刻，作为接收时刻；再根据发射时刻与接收时刻的时间差得到飞行时间。基于飞行时间与目标物311的距离确定误差信息，进而建立校准标定表。
以峰值法为例，校准的目标是对回波脉冲的峰值时间进行校准。根据发射探测激光脉冲的触发时刻，作为发射时刻；根据回波信号峰值的时刻，作为接收时刻。再根据发射时刻与接收时刻的时间差得到飞行时间；基于飞行时间与目标物311的距离确定误差信息，进而建立校准标定表。
根据本发明的一个优选实施例，所述多个目标物311可分别对应不同的测量信息，所述校准标定参数用于标定相应的测量信息。其中，所述测量信息例如为目标物的距离和/或反射率等。根据需求选择不同的测量信息，将测量值与目标物311的实际值相比较，确定误差信息，形成校准标定参数，进而建立所述激光雷达10的校准标定表，这些都在本发明的保护范围内。
根据本发明的又一个优选实施例，一个或多个目标物311具有不同的反射率。其中，在校准过程中设置的多个目标物311例如为不同反射率的目标板；当只有一个目标物311时，例如通过更换目标板上的贴纸来调整其反射率。校准方法10在按照上述三种方式实施时，控制转镜21依次停在至少一个角度位置，基于回波脉冲信息获取目标物311的反射率，基于测量值与目标物311的反射率确定误差信息，进而建立反射率的校准标定表。
综上所述，校准方法10通过步骤S11-S13实现如下：获取转镜21的目标位置信息后，通过控制逆变驱动电路25的各桥臂的开关状态和导通时间，调整控制电压U out中的多个空间矢量电压的矢量大小和占空比，从而实现控制电机22驱动转镜21旋转到目标位置；然后激光雷达20发射探测激光脉冲，获取目标物311-1上的回波脉冲信息，然后改变目标物311-1的方位或者对下一个目标物311-2，重复上述步骤，基于获得的多组回波脉冲信息确定与激光雷达20的测量信息(例如距离和/或反射率)对应的校准标定参数，进而建立校准标定表。当该激光雷达工作时，可根据测量信息，结合相应的校准标定表，获得精确的测量结果。
更优选地，逆变驱动电路25可选三相、五相或九相，都在本发明的保护范围内。
作为一个优选方案，本发明还可以结合比例积分微分(Proportional Integral Derivative，PID)控制技术，使得转镜21尽快稳定在目标位置。PID控制器的工作原理为:设定一个输出目标值,反馈系统传回输出值,如与目标值不一致,则存在一个误差,根据此误差调整输入值,直至输出达到目标值。图8示出了PID控制器的整体框图,通过测量元件获得系统的输出值后，通过比例、积分、微分三种运算方式中的一种或多种将反馈的输出值叠加到输入中，从而控制执行机构的输出值达到目标值。
根据本发明的一个优选实施例，步骤S12还包括：在电机22的转动过程中，获取转镜21的偏差位置信息，根据偏差位置信息调节控制电压，直至转镜21到达目标位置。根据本发明的一个优选实施例，根据所述转镜21的当前位置和目标位置获取所述偏差位置信息。例如，控制单元24包括PID控制器，通过位置传感器23测量转镜21的当前位置，反馈到PID控制模块的输入端，获取与输入的目标位置信息的偏差，基 于该偏差通过调节比例、积分和微分的方式调节控制电压，直至转镜21旋转到目标位置。此过程可不断重复以将转镜21自动且快速的固定到目标位置。
根据本发明的一个优选实施例，参考图2，所述激光雷达20还包括编码盘23，所述编码盘23即位置传感器，用于检测转镜21的位置。所述校准方法10还包括：通过编码盘23检测转镜21的当前位置。
以上为基于一个PID控制器对电机进行自动闭环控制，实际中可能用到三个PID控制器，从内环到外环依次是：电流环、速度环和位置环。亦即，通过电流反馈来控制电机电流(力矩)，然后通过控制力矩来控制电机的转速，最后通过控制电机的转速控制电机位置。
根据本发明的一个优选实施例，步骤S12还包括：在电机22的转动过程中，获取当前的电路参数信息，根据偏差位置信息以及电路参数信息调节控制电压U out，直至转镜21到达目标位置。对于转镜激光雷达的校准，需要控制转镜21的角度，使得出射光指向正前方的目标物311，通过前述空间矢量电压控制，结合编码盘23上的位置信息，通过闭环PID控制器，即可使得转镜21指向并锁定在所需的角度。由于在位置控制模式下，电机22转速很慢，使用编码盘23利用平均测速的方式输出的速度信息存在很大的误差(转子不动或者动得很慢，此时编码盘23无输出或者只输出一两个脉冲信号)，为了避免速度环带来的误差，在做位置控制的时候可以只使用位置和电流组成的双环进行控制，图9示出了本发明一个实施例的PID控制示意图，其中，控制单元24包括PID控制模块，当前位置信息可基于位置传感器23(例如编码盘上的光电传感器)获得，电路参数信息可根据电机22的输出获得。根据本发明的一个优选实施例，根据电机22的电流信息确定电路参数信息。其中，电流信息用于确定当前电机22的动力，并当转镜21靠近目标位置时，减小电流，以减小电机22转动的动力。从而，向PID控制模块的电流环输入电流信息，向PID控制模块中的位置环输入当前位置信息，例如角度位置信息，再与目标位置信息进行运算，即可通过反馈控制，让电机22驱动转镜21转到该目标角度。
具体地，参考图9，控制单元24包括PID控制模块以及空间矢量电压控制模块。首先，接收外部输入的转镜21的目标位置信息。然后，通过位置传感器23检测的当前位置信息，获得的偏差位置信息通过PID控制模块中的位置环转换为目标电流，同时，对电机22的输出相电流进行采样，PID控制模块中的电流环接收目标电流以及电机22输出的相电流，进行坐标系转换后，将目标电流转换为目标电压，并输出到空间矢量电压控制模块。最后经过空间矢量电压控制模块转换为控制电压U out，从而控制驱动电路25输出三相绕组坐标系的三相电压。
上述过程可以通过控制器24以及电机22的逆变驱动电路25完成，从而能够在雷达产品生产完成后，无需再经过拆卸，而可直接控制电机22驱动转镜21固定到目标角度。雷达出射光束角度固定后，即可根据目标物311的真实距离，快速获得当前光 束回波信号信息，从而获得例如距离校准及反射率校准的参数。
本发明还涉及一种计算机可读存储介质,包括存储于其上的计算机可执行指令，其中，所述可执行指令在被处理器执行时实施如上所述的校准方法10。
本发明还涉及一种激光雷达20，参考图2，包括转镜21和驱动所述转镜旋转的电机22，其中，所述激光雷达20还包括：
位置传感器23，配置为检测所述转镜21的位置信息；和
控制单元24，与所述电机22和所述位置传感器23耦接，配置为：
通过所述位置传感器23获取所述转镜21的至少一个目标位置；
根据所述至少一个目标位置，调节所述电机22的控制电压U out，以使得所述转镜21分别旋转至所述至少一个目标位置；其中，所述控制电压U out采用多个空间矢量电压合成获得；和
获取当所述转镜21在所述至少一个目标位置上时的回波脉冲信息，以对所述激光雷达20进行校准。
根据本发明的一个优选实施例，所述位置传感器23为编码盘，所述位置信息为角度位置。
根据本发明的一个优选实施例，所述激光雷达20还包括多相逆变驱动电路25，所述多相逆变驱动电路25耦接于所述控制单元24与所述电机22之间，配置为在所述控制单元24的控制下驱动所述电机22工作。其中，所述多相逆变驱动电路25可选三相、五相或九相等。
根据本发明的一个优选实施例，所述控制电压U out采用多个空间矢量电压中的一部分进行合成。亦即，控制电压U out可以选择多个空间矢量电压中的全部进行合成，也可以选择部分进行合成。例如，基于多个基本的空间矢量电压将平面坐标系划分为多个扇区，根据控制电压U out所在扇区，从多个基本的空间矢量电压中选择几个空间矢量电压进行合成。
根据本发明的一个优选实施例，所述多相逆变驱动电路25为三相逆变驱动电路，所述多个空间矢量电压为六个空间矢量电压，所述多个空间矢量电压中的一部分为两个空间矢量电压。例如，基于六个基本的空间矢量电压将平面坐标系划分为六个扇区，根据控制电压U out所在扇区选择六个基本的空间矢量电压中与之相邻的两个进行合成。
根据本发明的一个优选实施例，所述控制单元24调节所述控制电压U out中的各个空间矢量电压的矢量大小和/或占空比，获得指定方向的电机力矩输出，以控制所述电机停转并指向固定方向。
根据本发明的一个优选实施例，在所述电机22的转动过程中，所述控制单元24获取所述转镜21的偏差位置信息，根据所述偏差位置信息调节所述控制电压U out，直至所述转镜21到达所述目标位置。
根据本发明的一个优选实施例，在所述电机22的转动过程中，所述控制单元24 获取当前的电路参数信息，根据所述偏差位置信息以及所述电路参数信息调节所述控制电压U out，直至所述转镜21到达目标位置。
根据本发明的一个优选实施例，还包括发射单元26和接收单元27，其中所述发射单元26配置为发射探测激光脉冲，所述接收单元27配置为获取所述探测激光脉冲出射至多个目标物311上的回波脉冲，所述控制单元24还配置为根据所述转镜21在所述至少一个目标位置上时获得的、与多个目标物311分别对应的回波脉冲信息，确定所述激光雷达20的校准标定参数。
根据本发明的一个优选实施例，所述多个目标物311可分别具有不同的距离和/或反射率。
根据本发明的一个优选实施例，所述回波脉冲信息包括所述回波脉冲的前沿、脉宽、坡度和峰值中的至少一项，所述控制单元24基于所述校准标定参数，通过对所述校准标定参数的数据进行计算处理，建立所述激光雷达20的校准标定表。
根据本发明的一个优选实施例，所述激光雷达还包括计算机可读存储介质,包括存储于其上的计算机可执行指令，所述可执行指令在被所述控制单元24执行时实施所述校准方法10。
本发明还涉及一种校准系统30，参考图1A，包括：
校准辅助装置31，所述校准辅助装置31包括至少一个设置在不同方位的目标物311；和
激光雷达20，所述激光雷达20包括转镜21和驱动所述转镜21旋转的电机22，所述激光雷达20还包括：
位置传感器23，配置为检测所述转镜21的位置信息；和控制单元24，与所述电机22和所述位置传感器23耦接，配置为：
通过所述位置传感器23获取所述转镜21的至少一个目标位置；
根据所述至少一个目标位置，调节所述电机22的控制电压，以使得所述转镜21分别旋转至所述至少一个目标位置；其中，所述控制电压采用多个空间矢量电压合成获得；和
获取当所述转镜21在所述至少一个目标位置上时的回波脉冲信息，以对所述激光雷达20进行校准。
其中，所述至少一个目标位置与所述至少一个设置在不同方位的目标物311相对应。
最后应说明的是：以上所述仅为本发明的优选实施例而已，并不用于限制本发明，尽管参照前述实施例对本发明进行了详细的说明，对于本领域的技术人员来说，其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换。凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (26)

  1. 一种激光雷达的校准方法，其中，所述激光雷达包括转镜和驱动所述转镜旋转的电机，所述校准方法包括：
    S11：获取所述转镜的至少一个目标位置；
    S12：根据所述至少一个目标位置，调节所述电机的控制电压，以使得所述转镜分别旋转至所述至少一个目标位置；其中，所述控制电压采用多个空间矢量电压合成获得；和
    S13：根据所述转镜在所述至少一个目标位置上时，获得的回波脉冲信息对所述激光雷达进行校准。
  2. 根据权利要求1所述的校准方法，其中，所述步骤S12包括：调节所述控制电压中的各个空间矢量电压的矢量大小和/或占空比，获得指定方向的电机力矩输出，以使得所述转镜到达所述目标位置。
  3. 根据权利要求1所述的校准方法，其中，所述步骤S12包括：根据所述至少一个目标位置以及所述转镜对应的负载信息，调节所述电机的控制电压，以使得所述转镜分别旋转至所述至少一个目标位置。
  4. 根据权利要求3所述的校准方法，其中，根据所述转镜对应的负载信息获取反向力矩，矫正电机力矩输出。
  5. 根据权利要求1所述的校准方法，其中，所述步骤S12还包括：在所述电机的转动过程中，获取所述转镜的偏差位置信息，根据所述偏差位置信息调节所述控制电压，直至所述转镜到达所述目标位置。
  6. 根据权利要求5所述的校准方法，其中，根据所述转镜的当前位置和目标位置获取所述偏差位置信息。
  7. 根据权利要求5所述的校准方法，其中，步骤S12还包括：在所述电机的转动过程中，获取当前的电路参数信息，根据所述偏差位置信息以及所述电路参数信息调节所述控制电压，直至所述转镜到达目标位置。
  8. 根据权利要求7所述的校准方法，其中，根据所述电机的电流信息确定所述电路参数信息。
  9. 根据权利要求1-8中任一项所述的校准方法，其中，所述激光雷达还包括编码盘，所述校准方法还包括：通过所述编码盘检测所述转镜的当前位置。
  10. 根据权利要求1-8中任一项所述的校准方法，其中，所述校准方法还包括：所 述激光雷达发射探测激光脉冲，并获取所述探测激光脉冲出射至多个目标物上的回波脉冲；并且，根据所述转镜在所述至少一个目标位置上时获得的、与多个目标物分别对应的回波脉冲信息，确定所述激光雷达的校准标定参数。
  11. 根据权利要求10所述的校准方法，其中，所述多个目标物可分别对应不同的测量信息，所述校准标定参数用于标定相应的测量信息。
  12. 根据权利要求1-8中任一项所述的校准方法，其中，所述回波脉冲信息包括所述回波脉冲的前沿、脉宽、坡度和峰值中的至少一项，所述校准方法还包括：基于所述校准标定参数，通过对所述校准标定参数的数据进行计算处理，建立所述激光雷达的校准标定表。
  13. 一种计算机可读存储介质,包括存储于其上的计算机可执行指令，其中，所述可执行指令在被处理器执行时实施如权利要求1-12中任一项所述的校准方法。
  14. 一种激光雷达，包括转镜和驱动所述转镜旋转的电机，其中，所述激光雷达还包括：
    位置传感器，配置为检测所述转镜的位置信息；和
    控制单元，与所述电机和所述位置传感器耦接，配置为：
    通过所述位置传感器获取所述转镜的至少一个目标位置；
    根据所述至少一个目标位置，调节所述电机的控制电压，以使得所述转镜分别旋转至所述至少一个目标位置；其中，所述控制电压采用多个空间矢量电压合成获得；和
    获取当所述转镜在所述至少一个目标位置上时的回波脉冲信息，以对所述激光雷达进行校准。
  15. 根据权利要求14所述的激光雷达，其中，所述位置传感器为编码盘，所述位置信息为角度位置。
  16. 根据权利要求14所述的激光雷达，其中，所述激光雷达还包括多相逆变驱动电路，所述多相逆变驱动电路耦接于所述控制单元与所述电机之间，配置为在所述控制单元的控制下驱动所述电机工作。
  17. 根据权利要求16所述的激光雷达，其中，所述控制电压采用所述多个空间矢量电压中的一部分进行合成。
  18. 根据权利要求17所述的激光雷达，其中，所述多相逆变驱动电路为三相逆变驱动电路，所述多个空间矢量电压为六个空间矢量电压，所述多个空间矢量电压中 的一部分为两个空间矢量电压。
  19. 根据权利要求16所述的激光雷达，其中，所述控制单元通过控制所述多相逆变驱动电路的开关状态和持续时间，以调节所述控制电压中的各个空间矢量电压的矢量大小和/或占空比，获得指定方向的电机力矩输出，以控制所述电机停转并指向固定方向。
  20. 根据权利要求14所述的激光雷达，其中，在所述电机的转动过程中，所述控制单元获取所述转镜的偏差位置信息，根据所述偏差位置信息调节所述控制电压，直至所述转镜到达所述目标位置。
  21. 根据权利要求20所述的激光雷达，其中，在所述电机的转动过程中，所述控制单元获取当前的电路参数信息，根据所述偏差位置信息以及所述电路参数信息调节所述控制电压，直至所述转镜到达目标位置。
  22. 根据权利要求14-21中任一项所述的激光雷达，其中，还包括发射单元和接收单元，其中所述发射单元配置为发射探测激光探测，所述接收单元配置为获取所述探测激光脉冲出射至多个目标物上的回波脉冲，所述控制单元还配置为根据所述转镜在所述至少一个目标位置上时获得的、与多个目标物分别对应的回波脉冲信息，确定所述激光雷达的校准标定参数。
  23. 根据权利要求22所述的激光雷达，其中，所述多个目标物可分别对应不同的测量信息，所述校准标定参数用于标定相应的测量信息。
  24. 根据权利要求14-21中任一项所述的激光雷达，其中，所述回波脉冲信息包括所述回波脉冲的前沿、脉宽、坡度和峰值中的至少一项，所述控制单元基于所述校准标定参数，通过对所述校准标定参数的数据进行计算处理，建立所述激光雷达的校准标定表。
  25. 根据权利要求24所述的激光雷达，其中，所述激光雷达还包括计算机可读存储介质,包括存储于其上的计算机可执行指令，所述可执行指令在被所述控制单元执行时实施如权利要求1-12中任一项所述的校准方法。
  26. 一种校准系统，包括：
    校准辅助装置，所述校准辅助装置包括至少一个设置在不同方位的目标物；和激光雷达，所述激光雷达包括转镜和驱动所述转镜旋转的电机，所述激光雷达还包括：
    位置传感器，配置为检测所述转镜的位置信息；和
    控制单元，与所述电机和所述位置传感器耦接，配置为：
    通过所述位置传感器获取所述转镜的至少一个目标位置；
    根据所述至少一个目标位置，调节所述电机的控制电压，以使得所述转镜分别旋转至所述至少一个目标位置；其中，所述控制电压采用多个空间矢量电压合成获得；和
    获取当所述转镜在所述至少一个目标位置上时的回波脉冲信息，以对所述激光雷达进行校准。
    其中，所述至少一个目标位置与所述至少一个设置在不同方位的目标物相对应。
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