Laser radar

Abstract

The utility model discloses a laser radar which comprises a laser ranging unit, a temperature drift detection unit and a control circuit. The laser ranging unit comprises a first transmitter, a collimating lens, a receiving lens and a light receiver; the temperature drift detection unit comprises a second emitter and a reflecting surface; light emitted by the second emitter enters the light receiver through the reflecting surface; the control circuit comprises a driving circuit, a timer and a calculation circuit; a first driving output end of the driving circuit is connected with the first transmitter, and a second driving output end is connected with the second transmitter; the timer measures a second timing time from signal emission of the second driving output end to reception of the optical receiver signal and a first timing time from signal emission of the first driving output end to reception of the optical receiver signal; the calculation circuit generates a temperature drift error signal according to the second timing time; and calculating the distance according to the first timing time, and subtracting the temperature drift error signal to obtain the distance after the temperature drift is eliminated. According to the utility model, the technical problem that temperature drift affects distance measurement is solved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to laser ranging technical field, concretely relates to a laser radar. BACKGROUND

[0002] As a new type of distance measurement means, the laser radar has the advantages of fast measurement speed, high data precision and strong real-time performance.

[0003] The laser radar usually uses the direct time of flight method to measure the distance, that is, the total flight time of the laser from the laser radar to the target object, reflected by the target object and received by the laser radar is measured, and the distance of the target object is obtained by multiplying the speed of light in the air. From the basic principle of this method, it can be known that the accuracy of time measurement is extremely high, and a more accurate measurement accuracy can be obtained in the order of picoseconds.

[0004] However, in the actual working process, the temperature of the internal circuit of the laser radar is usually changed by tens of degrees Celsius due to the influence of the environment, which causes the performance drift of the working circuit caused by the temperature change, which is called temperature drift. Temperature drift is an unavoidable problem in the actual laser radar ranging system, therefore, how to eliminate the influence of temperature drift in the ranging process is a problem that must be solved by the laser radar. SUMMARY

[0005] The utility model provides a kind of laser radar, solve the technical problem of temperature drift influence ranging in prior art.

[0006] To achieve the above technical purpose, the utility model adopts the following technical scheme:

[0007] A kind of laser radar, comprising:

[0008] Laser ranging unit, it includes first transmitter, collimating lens, receiving lens, optical receiver;The light emitted by the first transmitter is shot to target object after collimating lens, and the light reflected by the target object is shot into receiving lens, and the light converged after receiving lens is shot into optical receiver, and the optical receiver sends electric signal after receiving light;

[0009] Temperature drift detection unit, it includes second transmitter, reflecting surface;The light emitted by the second transmitter is shot into optical receiver after reflecting by reflecting surface;

[0010] Control circuit, comprising:

[0011] Drive circuit, its first drive output end is connected with the first transmitter, and its second drive output end is connected with the second transmitter;

[0012] a timer, which is used to measure a second timing time from the second driving output end sending a driving signal to receiving an electric signal sent by the light receiver; and is also used to measure a first timing time from the first driving output end sending a driving signal to receiving an electric signal sent by the light receiver;

[0013] a calculation circuit, which generates a temperature drift error signal according to the second timing time; and calculates a distance to the target object according to the first timing time, and subtracts the temperature drift error signal to obtain a distance after eliminating temperature drift.

[0014] In some embodiments of the present application, the calculation circuit comprises a first register, a second register, a third register, a fourth register, a first multiplier, a second multiplier, a first subtractor and a second subtractor.

[0015] The timer has a first input end connected to a first trigger output end of the driving circuit, a second input end connected to a second trigger output end of the driving circuit, a third input end connected to an output end of the light receiver, a first output end connected to an input end of the first multiplier, and a second output end connected to an input end of the second multiplier.

[0016] The first register is used to store a speed c of light in air.

[0017] The second register is used to store a sum of a distance from the second emitter to the reflecting surface and a distance from the reflecting surface to the light receiver.

[0018] The second multiplier is used to multiply the speed c in the first register and the second timing time t output by the second output end of the timer.

[0019] The second subtractor is used to subtract the sum of distances in the second register from the product output by the second multiplier to obtain a temperature drift error signal.

[0020] The third register is used to store the temperature drift error signal output by the second subtractor.

[0021] The first multiplier is used to multiply the speed c in the first register, the first timing time T output by the first output end of the timer and a multiplier stored in the fourth register.

[0022] The first subtractor is used to subtract the temperature drift error signal in the third register from the product output by the first multiplier to obtain a distance after eliminating temperature drift.

[0023] In some embodiments of the present application, an optical path between the second emitter and the reflecting surface is perpendicular to an optical path between the receiving lens and the light receiver.

[0024] In some embodiments of the present application, the laser radar further comprises a structure, the structure having a first sleeve and a second sleeve arranged in a top-bottom manner; the first sleeve is located above the second sleeve;

[0025] The first sleeve is arranged in a transverse manner and has a front end opening and a rear end opening; the collimating lens is installed in the first sleeve and blocks the front end opening of the first sleeve; the first emitter is located in the first sleeve and close to the rear end opening of the first sleeve; the first emitter is fixed on an emission circuit board and electrically connected with the emission circuit board; the emission circuit board is electrically connected with a control board, the control circuit is arranged on the control board and electrically connected with the control circuit, and the control board is fixed on the structure;

[0026] The second sleeve is arranged in a transverse manner and has a front end opening and a rear end opening; the receiving lens is installed in the second sleeve and blocks the front end opening of the second sleeve; the light receiver is located in the second sleeve and close to the rear end opening of the second sleeve; the light receiver is fixed on a receiving circuit board and electrically connected with the receiving circuit board; the receiving circuit board is electrically connected with the control board;

[0027] The second emitter and the reflecting surface are oppositely arranged on the inner side wall of the second sleeve.

[0028] In some embodiments of the present application, the inner diameter of the first sleeve gradually decreases from the front end opening to the rear end opening.

[0029] In some embodiments of the present application, the second sleeve is sequentially provided with a first variable-diameter section and a second variable-diameter section from the front end opening to the rear end opening.

[0030] The inner diameter of the first variable-diameter section gradually decreases from the front end opening to the rear end opening.

[0031] The inner diameter of the second variable-diameter section gradually increases from the front end opening to the rear end opening.

[0032] The receiving lens is located in the first variable-diameter section, the light receiver is located in the second variable-diameter section, and the second emitter and the reflecting surface are oppositely arranged on the inner side wall of the second variable-diameter section.

[0033] In some embodiments of the present application, the shell of the laser radar comprises an optical cover and a lower shell, the optical cover is located above the lower shell and detachably connected with the lower shell.

[0034] The structure is located in the optical cover.

[0035] The motor of the laser radar is located in the lower shell, and the stator of the motor is fixed with the lower shell, and the rotor of the motor is fixed with the structure body to drive the structure body to rotate.

[0036] In some embodiments of the present application, the laser radar comprises an angle code disc and an optical encoder.

[0037] The angle code disc is a circular ring structure, which is sleeved outside the rotor of the motor, coaxially arranged with the rotor, and fixedly connected with the rotor; the top end of the angle code disc has a tooth groove matched with the optical encoder;

[0038] The optical encoder is fixedly connected with the lower shell, detects the rotation angle of the rotor, and sends the detected angle signal to the main control unit of the laser radar.

[0039] In some embodiments of the present application, the laser radar further comprises an optical communication module, the optical communication module comprising an optical communication transmitting end and an optical communication receiving end;

[0040] The optical communication transmitting end and the optical communication receiving end are arranged in the hollow shaft of the motor; the optical communication receiving end and the optical communication transmitting end perform optical signal transmission;

[0041] The optical communication transmitting end is electrically connected with the control circuit; the optical communication receiving end is electrically connected with the main control unit of the laser radar.

[0042] In some embodiments of the present application, the laser radar further comprises a wireless power receiving module and a wireless power transmitting module.

[0043] The wireless power receiving module is sleeved outside the rotor of the motor and fixedly connected with the rotor;

[0044] The wireless power transmitting module is located below the wireless power receiving module and fixedly connected with the lower shell;

[0045] The wireless power transmitting module generates an alternating magnetic field, and the wireless power receiving module generates an induced current to supply power to the first transmitter, the second transmitter, the light receiver and the control circuit.

[0046] Compared with the prior art, the laser radar has the advantages and positive effects that: the laser radar is provided with a temperature drift detection unit, a laser ranging unit and a control circuit, the calculation circuit of the control circuit generates a temperature drift error signal according to the second timing time from the driving signal sent from the second driving output end to the electric signal sent by the light receiver, the calculation circuit calculates the distance from the target according to the first timing time from the driving signal sent from the first driving output end to the electric signal sent by the light receiver, and subtracts the temperature drift error signal to obtain the distance after eliminating the temperature drift, so as to eliminate the influence of the temperature drift on the laser ranging, solve the technical problem of the temperature drift affecting the ranging in the prior art, and improve the laser ranging accuracy.

[0047] Other features and advantages of the present application will become more apparent from the following detailed description of the embodiments of the present application when read together with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0048] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained according to these drawings without creative labor for those skilled in the art.

[0049] Figure 1 is a sectional view of an embodiment of the laser radar proposed by the present application;

[0050] Figure 2 is an exploded view of an embodiment of the laser radar proposed by the present application;

[0051] Figure 3 is Figure 1 is a structural schematic view of an embodiment of the laser ranging unit in the laser radar;

[0052] Figure 4 is a structural schematic view of an embodiment of the temperature drift detection unit;

[0053] Figure 5 is a circuit structure schematic view of an embodiment of the control circuit;

[0054] Figure 6 is a circuit structure schematic view of another embodiment of the control circuit.

[0055] Reference signs:

[0056] 10, laser ranging unit; 11, first transmitter; 12, collimating lens; 13, receiving lens; 14, light receiver; 15, transmitting circuit board; 16, receiving circuit board;

[0057] 20, temperature drift detection unit; 21, second transmitter; 22, reflecting surface;

[0058] 30, structure; 31, first sleeve; 32, second sleeve; 32-1, first variable diameter section; 32-2, second variable diameter section;

[0059] 40, motor; 41, rotor; 42, stator;

[0060] 51, optical cover; 52, lower housing;

[0061] 61, angle encoder; 62, photoelectric encoder;

[0062] 71, optical communication transmitting end; 72, optical communication receiving end;

[0063] 81, wireless power receiving module; 82, wireless power transmitting module;

[0064] 91, control board;

[0065] 100, target object. DETAILED DESCRIPTION

[0066] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0067] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0068] In the description of the present application, it should be understood that the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features limited by "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0069] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "linking" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0070] The laser radar of the embodiment includes a laser ranging unit 10, a temperature drift detection unit 20, a control circuit, etc.

[0071] The laser ranging unit 10 (also referred to as a first optical path structure) includes a first emitter 11, a collimating lens 12, a receiving lens 13, and a light receiver 14. The light emitted by the first emitter 11 is collimated by the collimating lens 12 and then irradiates the target object 100. The light reflected by the target object 100 irradiates the receiving lens 13, and the light converged by the receiving lens 13 irradiates the light receiver 14. The light receiver 14 sends out an electrical signal after receiving the light. See Figures 1 to 4 illustrated.

[0072] The temperature drift detection unit 20 (also referred to as a second optical path structure) includes a second emitter 21 and a reflecting surface 22. The light emitted by the second emitter 21 is reflected by the reflecting surface 22 and then irradiates the light receiver 14. See Figures 1 to 4 illustrated.

[0073] The first emitter 11 is driven by the control circuit to emit laser light, which is used to realize the ranging function.

[0074] The collimating lens 12 is mainly used to collimate the laser light emitted by the first emitter 11, so as to realize a smaller divergence angle and detect a target object at a farther distance.

[0075] The receiving lens 13 is mainly used to receive the laser light reflected by the target object and converge the laser light to irradiate the light receiver 14.

[0076] The light receiver 14 is mainly used to receive the back light signal and give feedback to the light signal meeting the triggering condition, so as to trigger the control circuit to complete the time calculation.

[0077] The second emitter 21 is driven by the control circuit to emit laser light, which is used to measure the temperature drift error signal.

[0078] The reflecting surface 22 is used to change the direction of the laser light emitted by the second emitter 21, so that the laser light can irradiate the light receiver 14.

[0079] The control circuit includes a driving circuit, a timer, a calculation circuit, etc.

[0080] The driving circuit has a first driving output end connected to the first emitter 11, and sends a driving signal to the first emitter 11 to drive the first emitter 11 to emit light; and has a second driving output end connected to the second emitter 21, and sends a driving signal to the second emitter 21 to drive the second emitter 21 to emit light. The first emitter 11 and the second emitter 21 do not emit light at the same time, i.e. the driving circuit drives the first emitter 11 and the second emitter 21 to work at different times.

[0081] The timer is used to measure a second timing time t from the driving circuit sending the driving signal to the second driving output end to receiving the electric signal sent by the light receiver; and is also used to measure a first timing time T from the driving circuit sending the driving signal to the first driving output end to receiving the electric signal sent by the light receiver.

[0082] The calculation circuit generates a temperature drift error signal according to the second timing time; and calculates the distance to the target object according to the first timing time, and subtracts the temperature drift error signal to obtain the distance after eliminating the temperature drift.

[0083] The distance between the second emitter 21 and the reflecting surface 22 is fixed, the distance between the reflecting surface 22 and the light receiver 14 is fixed, the sum d0 of the two distances is also fixed, and the speed c of light in air is also fixed, which are pre-stored in a register. Therefore, the light emitted by the second emitter 21 is reflected by the reflecting surface 22 and then enters the light receiver 14, and the distance d0 of the light path is fixed.

[0084] The timer starts timing when the second driving output end of the driving circuit sends the driving signal; and stops timing when the timer receives the electric signal sent by the light receiver.

[0085] The timer records the time from the driving circuit sending the driving signal to the second driving output end to the timer receiving the electric signal sent by the light receiver, and the time is recorded as the second timing time t. The calculation circuit calculates d=c×t, and the difference γ between d and d0 is the temperature drift error signal, i.e. γ=d-d0=c×t-d0.

[0086] The timer starts timing when the first driving output end of the driving circuit sends the driving signal; and stops timing when the timer receives the electric signal sent by the light receiver.

[0087] The timer records the time from the driving circuit sending the driving signal to the first driving output end to the timer receiving the electric signal sent by the light receiver, and the time is recorded as the first timing time T.

[0088] According to the laser ranging principle, laser is emitted from the first emitter 11 to the target object, reflected by the target object and received by the light receiver 14, and the transmission distance of the laser in this process is twice the distance from the target object. Therefore, by timing the first timing time T from the driving signal sent by the first driving output end of the driving circuit to the electric signal sent by the light receiver 14, the calculation circuit can calculate the distance D = c x T / 2 from the target object.

[0089] The calculated distance D is compensated by the temperature drift error signal, that is, the temperature drift error signal is subtracted, and the distance D0 after eliminating the temperature drift is D - γ.

[0090] The driving circuit drives the first emitter 11 and the second emitter 21 to work in time division, and emits light in time division. When the temperature drift error signal needs to be generated, the second driving output end of the driving circuit drives the second emitter 21 to emit light, the timer records the second timing time, and the calculation circuit calculates the temperature drift error signal γ. When the distance from the target object needs to be measured, the first driving output end of the driving circuit drives the first emitter 11 to emit light, the timer records the first timing time, the calculation circuit calculates the distance D from the target object, and subtracts the temperature drift error signal γ to obtain the distance D0 after eliminating the temperature drift.

[0091] Generally, the speed c of light in air is constant, and the dimensional error of the structure of the laser radar caused by temperature change can also be basically ignored, so the temperature drift error mainly comes from the change of the timing time of the circuit part, that is, the temperature drift of the control circuit.

[0092] When the timer records the second timing time t and the calculation circuit calculates d, the temperature drift difference caused by temperature change is the same as when the timer records the first timing time T and the calculation circuit calculates D, so the temperature drift error signal (γ = d - d0) can be used to compensate the calculated distance D from the target object, and the distance D0 after eliminating the temperature drift is D - γ.

[0093] In the calculation of the temperature drift error signal and the distance from the target object, the light receiver and the control circuit work in time division, which can eliminate the error caused by temperature drift.

[0094] The laser radar of the embodiment, by designing the temperature drift detection unit, the laser ranging unit and the control circuit, the calculation circuit of the control circuit generates the temperature drift error signal according to the second timing time from the driving signal sent by the second driving output end to the electric signal sent by the light receiver, and the calculation circuit calculates the distance from the target object according to the first timing time from the driving signal sent by the first driving output end to the electric signal sent by the light receiver, and subtracts the temperature drift error signal to obtain the distance after eliminating the temperature drift, so as to eliminate the influence of temperature drift on laser ranging, solve the technical problem of temperature drift affecting ranging in the prior art, and improve the accuracy of laser ranging.

[0095] The laser radar of the embodiment eliminates the influence of temperature drift and realizes the ranging basic function.

[0096] In some embodiments of the application, the calculation circuit includes a first register, a second register, a third register, a fourth register, a first multiplier, a second multiplier, a first subtractor, a second subtractor, etc., as shown in Figure 5 .

[0097] The timer has a first input end connected to the first trigger output end of the driving circuit, a second input end connected to the second trigger output end of the driving circuit, a third input end connected to the output end of the light receiver, a first output end connected to the input end of the first multiplier, and a second output end connected to the input end of the second multiplier.

[0098] When the second driving output end of the driving circuit sends a driving signal, the second trigger output end of the driving circuit outputs a start signal to the second input end of the timer, and the timer starts timing, which is recorded as a second start time; when the third input end of the timer receives the electrical signal sent by the light receiver, the timer stops timing, which is recorded as a second end time; the second end time is subtracted from the second start time to obtain a second timing time t, and the second output end of the timer outputs the second timing time t to the input end of the second multiplier.

[0099] When the first driving output end of the driving circuit sends a driving signal, the first trigger output end of the driving circuit outputs a start signal to the first input end of the timer, and the timer starts timing, which is recorded as a first start time; when the third input end of the timer receives the electrical signal sent by the light receiver, the timer stops timing, which is recorded as a first end time; the first end time is subtracted from the first start time to obtain a first timing time T, and the first output end of the timer outputs the first timing time T to the input end of the first multiplier.

[0100] The first register is used to store the speed c of light in air.

[0101] The second register is used to store the sum d0 of the distance from the second emitter to the reflecting surface and the distance from the reflecting surface to the light receiver. That is, d0 is equal to the distance between the second emitter 21 and the reflecting surface 22, plus the distance between the reflecting surface 22 and the light receiver 14.

[0102] The fourth register is used to store the multiplier 0.5.

[0103] The second multiplier is used to multiply the speed c in the first register and the second timing time t output by the second output end of the timer, and the product is d = c x t.

[0104] a second subtractor for subtracting the sum of distances d0 in the second register from the product d output by the second multiplier to obtain a temperature drift error signal γ = d - d0.

[0105] a third register for storing the temperature drift error signal γ output by the second subtractor.

[0106] a first multiplier for multiplying the speed c in the first register, the first timing time T output by the first output end of the timer, and the multiplier 0.5 stored in the fourth register, and the product is D = c x T x 0.5.

[0107] a first subtractor for subtracting the temperature drift error signal γ in the third register from the product D output by the first multiplier to obtain the distance after eliminating the temperature drift D0 = D - γ.

[0108] By designing the above-mentioned calculation circuit, the temperature drift error signal can be calculated by using components, and the distance after eliminating the temperature drift is finally obtained, the influence of the temperature drift is eliminated, the circuit is simple to build, the cost is low, and the implementation is convenient.

[0109] When the second transmitter needs to work, the second driving output end of the driving circuit sends a driving signal to the second transmitter, and the timer measures a second timing time t from when the driving signal is sent by the second driving output end to when the electrical signal sent by the optical receiver is received. The second multiplier multiplies the speed c in the first register and the second timing time t output by the second output end of the timer to obtain a product d = c x t. The second subtractor subtracts the distance d0 in the second register from the product d output by the second multiplier to obtain a temperature drift error signal γ = d - d0.

[0110] When the first transmitter needs to work, the first driving output end of the driving circuit sends a driving signal to the first transmitter, and the timer measures a first timing time T from when the driving signal is sent by the first driving output end to when the electrical signal sent by the optical receiver is received. The first multiplier multiplies the speed c in the first register, the first timing time T output by the first output end of the timer, and the multiplier 0.5 stored in the fourth register to obtain a product D = c x T x 0.5. The first subtractor subtracts the temperature drift error signal γ in the third register from the product D output by the first multiplier to obtain the distance after eliminating the temperature drift D0 = D - γ.

[0111] In some embodiments of the present application, since the first transmitter and the second transmitter do not work at the same time, the inside of the timer can be designed with only one timing unit.

[0112] In some other embodiments of the present application, the inside of the timer can also be designed with two timing units: a first timing unit and a second timing unit, as shown in Figure 6

[0113] ​The second timing unit measures a second timing time t from the second drive output of the drive circuit sending a drive signal to the second timing unit receiving an electric signal sent by the light receiver.

[0114] The first timing unit measures a first timing time T from the first drive output of the drive circuit sending a drive signal to the first timing unit receiving an electric signal sent by the light receiver.

[0115] When the second drive output of the drive circuit sends a drive signal, the second trigger output of the drive circuit outputs a start signal to the second timing unit, and the second timing unit starts timing; when the second timing unit receives an electric signal sent by the light receiver, the second timing unit stops timing, and the second timing unit outputs the second timing time t to the input end of the second multiplier.

[0116] When the first drive output of the drive circuit sends a drive signal, the first trigger output of the drive circuit outputs a start signal to the first timing unit, and the first timing unit starts timing; when the first timing unit receives an electric signal sent by the light receiver, the first timing unit stops timing, and the first timing unit outputs the first timing time T to the input end of the first multiplier.

[0117] The laser radar of the embodiment is provided with a fixed-angle reflecting surface (diffuse reflecting surface) at the opposite position of the second transmitter, the second light path is completely overlapped with the first light path at the position of the light receiver, the drive circuit drives the second transmitter to send short-pulse light, the timer records the second start time, the light sent by the second transmitter is reflected by the reflecting surface and irradiates the light receiver, the light receiver generates a drive electric signal after receiving the light signal and sends the drive electric signal to the timer, so that the timer obtains the second end time, the second end time is subtracted from the second start time to obtain the second timing time t, and the temperature drift error signal γ=c×t-d0.

[0118] The first transmitter is located behind the collimating lens, the drive circuit drives the first transmitter to send short-pulse light, the timer records the first start time, the light sent by the first transmitter is collimated by the collimating lens and flies to the measured target object. The light receiver is located behind the receiving lens, the light returned from the measured target object converges by the receiving lens and irradiates the light receiver, the light receiver generates a drive electric signal after receiving the light signal and sends the drive electric signal to the timer, so that the timer obtains the first end time, the first end time is subtracted from the first start time to obtain the first timing time T, and the distance D0 after eliminating the temperature drift is c×T×0.5-γ.

[0119] The control circuit is a precision measurement circuit that primarily calculates the start and end times. It couples with the corresponding drive circuit to drive the transmitter and receive the optical receiver's drive signal. It is the core circuit of the LiDAR and the primary source of temperature drift. For example, under certain temperature conditions, the time from when the timer starts counting the start time to when the first transmitter emits a pulse of light becomes longer. Under other temperature conditions, the optical receiver's response is slow, and the time from receiving the light signal to converting it into the drive electrical signal captured by the timer becomes longer. This adds an unexpected delay between the start and end times, causing the calculated measured distance to become longer, thus affecting ranging accuracy.

[0120] The distance d0 that the light beam travels from the second emitter through the reflecting surface to the optical receiver is physically a constant value and can be called a reference scale. When the lidar is affected by temperature and produces the aforementioned temperature drift, the same temperature drift will also occur in the second optical path. That is, if the driving time of the second emitter to emit pulsed light becomes longer or the time it takes for the optical receiver to drive the timer to obtain the end time becomes longer, then the reference scale measurement value d obtained through the second optical path will deviate from the actual value d0 of the reference scale by γ (i.e., the temperature drift error signal). This deviation γ is the relative impact of temperature drift on the lidar, γ = d - d0.

[0121] By subtracting the corresponding temperature drift deviation γ from the distance measurement value D obtained through the first optical path, the accurate distance measurement value D0=D-γ can be obtained. That is, the difference γ between the measured value d and the actual value d0 of the reference ruler can eliminate the distance measurement influence of temperature drift in the first optical path.

[0122] The laser radar of this embodiment measures the reference scale by adding a relatively independent second optical path, and then uses the difference γ to completely eliminate the influence of temperature drift in the ranging system in a calculable manner. Compared with other methods of eliminating temperature drift by measuring temperature and performing table lookup compensation at different temperatures, the laser radar of this embodiment does not require a large amount of preliminary testing to obtain a compensation value database, and is simple to use and has better accuracy.

[0123] In some embodiments of the present application, the optical path between the second emitter 21 and the reflective surface 22 and the optical path between the receiving lens 13 and the optical receiver 14 are perpendicular to each other. Figure 4 As shown, this reduces the overlap between the two light paths and reduces the chance of mutual influence.

[0124] In some embodiments of the present application, the laser radar further includes a structure 30 , which includes a first sleeve 31 and a second sleeve 32 arranged up and down; the first sleeve 31 is located above the second sleeve 32 .

[0125] The first sleeve 31 is arranged horizontally and has a front end opening and a rear end opening; the collimating lens 12 is installed in the first sleeve 31 and blocks the front end opening of the first sleeve 31; the first emitter 11 is located in the first sleeve 31 and is close to the rear end opening of the first sleeve 31; the first emitter 11 is fixed on the transmitting circuit board 15 and is electrically connected to the transmitting circuit board 15; the transmitting circuit board 15 is electrically connected to the control board 91, and the control circuit is arranged on the control board 91 and is electrically connected to the control circuit, and the control board 91 is fixed on the structure 30.

[0126] The second sleeve 32 is arranged horizontally and has a front end opening and a rear end opening; the receiving lens 13 is installed in the second sleeve 32 and blocks the front end opening of the second sleeve 32; the optical receiver 14 is located in the second sleeve 32 and is close to the rear end opening of the second sleeve 32; the optical receiver 14 is fixed on the receiving circuit board 16 and is electrically connected to the receiving circuit board 16, and the receiving circuit board 16 is electrically connected to the control board 91.

[0127] The second emitter 21 and the reflective surface 22 are disposed opposite to each other on the inner wall of the second sleeve 32. The second emitter 21 is electrically connected to the control board 91.

[0128] By designing the structure 30 as a first sleeve 31 and a second sleeve 32 arranged up and down, not only is the spatial layout reasonable, but it is also convenient to fix the first transmitter 11, the collimating lens 12, the receiving lens 13, the light receiver 14, the second transmitter 21, and the reflecting surface 22.

[0129] The first transmitter 11 is fixed on the transmitting circuit board 15, the optical receiver 14 is fixed on the receiving circuit board 16, and the control circuit is fixed on the control board 91. This not only facilitates the fixation of the first transmitter 11, the optical receiver 14, and the control circuit, but also facilitates the communication between the first transmitter 11, the optical receiver 14 and the control circuit.

[0130] The signal transmission process between the control circuit and the first transmitter 11 is: control circuit→control board 91→transmitting circuit board 15→first transmitter 11.

[0131] The signal transmission process between the control circuit and the second transmitter 21 is: control circuit→control board 91→second transmitter 21.

[0132] The transmission process of the electrical signal between the optical receiver 14 and the control circuit is: optical receiver 14 →receiving circuit board 16 →control board 91 →control circuit.

[0133] In some embodiments of the present application, the inner diameter of the first sleeve 31 gradually decreases from the front opening to the rear opening.

[0134] The collimating lens 12 is large in volume and occupies a large space, so the inner diameter of the first sleeve 31 near the front end opening can be designed to be larger; the first emitter 11 is small in volume and occupies a small space, so the inner diameter of the first sleeve 31 near the rear end opening can be designed to be smaller, so as to reduce the size of the internal space of the first sleeve 31 and increase the structural strength of the structure 30.

[0135] In some embodiments of the present application, the second sleeve 32 is sequentially provided with a first variable diameter section 32-1 and a second variable diameter section 32-2 from the front end opening to the rear end opening, as shown in Figure 4 .

[0136] The first variable diameter section 32-1 gradually decreases in inner diameter from the front end opening to the rear end opening;

[0137] The second variable diameter section 32-2 gradually increases in inner diameter from the front end opening to the rear end opening;

[0138] The receiving lens 13 is located in the first variable diameter section 32-1 and is close to the front end opening of the second sleeve 32;

[0139] The light receiver 14 is located in the second variable diameter section 32-2 and is close to the rear end opening of the second sleeve 32;

[0140] The second emitter 21 and the reflecting surface 22 are oppositely arranged on the inner side wall of the second variable diameter section 32-2.

[0141] The receiving lens 13 is large in volume and occupies a large space, so the inner diameter of the first variable diameter section 32-1 near the front end opening can be designed to be larger; since the light receiver 14, the second emitter 21, and the reflecting surface 22 are arranged in the second variable diameter section 32-2, the inner diameter of the second variable diameter section 32-2 near the rear end opening needs to be designed to be larger.

[0142] By designing the second sleeve 32 to have a gradually decreasing inner diameter from the front end opening to the rear end opening and then a gradually increasing inner diameter, the receiving lens 13, the second emitter 21, and the reflecting surface 22 can be conveniently installed, and the size of the internal space of the second sleeve 32 is minimized to increase the structural strength of the structure 30.

[0143] In some embodiments of the present application, the reflecting surface 22 is part of the inner side wall of the second variable diameter section 32-2 of the second sleeve 32.

[0144] In some embodiments of the present application, the shell of the laser radar includes an optical cover 51 and a lower shell 52, the optical cover 51 is located above the lower shell 52, and the optical cover 51 and the lower shell 52 are detachably connected, which is convenient to disassemble and assemble. For example, the bottom end surface of the optical cover 51 is in contact with the top end surface of the lower shell 52 and is connected together by screws.

[0145] The structure 30 is located in the optical cover 51. The optical cover 51 is generally made of an optical plastic material, and a laser used for distance measurement can be normally transmitted, and is mainly used for protecting an optical part of distance measurement.

[0146] The main function of the structure 30 is to provide structural support for each functional component and to physically isolate the emitting light path and the receiving light path.

[0147] The motor 40 of the laser radar is located in the lower shell 52, and the stator 42 of the motor is fixed with the lower shell 52, and the rotor 41 of the motor is fixed with the structure 30. The rotor 41 drives the structure 30 to rotate around the rotating shaft of the motor, and then drives the laser distance measurement unit and the temperature drift detection unit to complete the circumferential scanning.

[0148] The laser distance measurement unit and the temperature drift detection unit rotate with the structure 30 to realize the circumferential detection of the distance of the target object.

[0149] The lower shell 52 is a metal shell, which is a structural basis of the laser radar, and is used for fixing each functional component, providing structural support and external protection.

[0150] In some embodiments of the present application, in order to facilitate the acquisition of the rotation angle of the motor rotor, the laser radar comprises an angle code disc 61 and a photoelectric encoder 62.

[0151] The angle code disc 61 is a circular ring structure, which is sleeved outside the rotor 41 of the motor, coaxially arranged with the rotor 41, and fixedly connected with the rotor 41. The top end of the angle code disc 61 has a tooth groove matched with the photoelectric encoder 62.

[0152] The photoelectric encoder 62 is fixedly connected with the lower shell 52, detects the rotation angle of the rotor 41, and sends the detected angle signal to the main control unit of the laser radar.

[0153] The angle code disc 61 rotates with the rotor 41. In the rotation process, the tooth groove performs light transmission and light shielding conversion on the photoelectric encoder 62. The photoelectric encoder 62 acquires the rotation angle of the rotor according to the distribution of the tooth groove.

[0154] The real-time angle position of the rotor rotation is acquired by reading the tooth groove features on the angle code disc 61 through the photoelectric encoder 62.

[0155] The main control unit is located in the lower shell 52. The main control unit can acquire the angle of the rotor 41 according to the signal sent by the photoelectric encoder 62, and then can accurately acquire the orientation angle of the laser distance measurement unit.

[0156] In some embodiments of the present application, the laser radar further comprises an optical communication module, which comprises an optical communication transmitting end 71 and an optical communication receiving end 72, as shown in Figure 1

[0157] ​The motor is a hollow shaft rotary motor, that is, the rotating shaft of the motor is a hollow shaft, which is through from top to bottom, and the optical communication transmitting end 71 and the optical communication receiving end 72 are arranged in the hollow shaft of the motor from top to bottom, and the optical communication receiving end 72 and the optical communication transmitting end 71 perform optical signal transmission. The optical communication transmitting end 71 is located above the optical communication receiving end 72.

[0158] The optical communication transmitting end 71 is electrically connected with the control circuit, and the optical communication receiving end 72 is electrically connected with the main control unit of the laser radar.

[0159] By arranging the optical communication transmitting end 71 and the optical communication receiving end 72 in the hollow shaft of the motor from top to bottom, the hollow shaft is used to transmit optical signals for real-time information transmission, which not only reasonably utilizes the space, but also ensures the smooth transmission of optical signals.

[0160] The signal transmission process is: control circuit→control panel 91→optical communication transmitting end 71→optical communication receiving end 72→main control unit.

[0161] In some embodiments of the application, in order to conveniently supply power for the laser ranging unit and the temperature drift detection unit, the laser radar further comprises a wireless power receiving module 81 and a wireless power transmitting module 82.

[0162] The wireless power receiving module 81 is sleeved on the outside of the rotor 41 of the motor and is fixedly connected with the rotor 41.

[0163] The wireless power transmitting module 82 is located below the wireless power receiving module 81 and is fixedly connected with the lower shell 52.

[0164] The wireless power transmitting module 82 and the wireless power receiving module 81 are arranged in an upper and lower interval, the wireless power transmitting module 82 generates an alternating magnetic field, the wireless power receiving module 81 generates an induced current through electromagnetic induction in the alternating magnetic field, and the first transmitter 11, the second transmitter 21, the optical receiver 14, the control circuit and the like are powered.

[0165] The wireless power transmitting module 82 and the wireless power receiving module 81 are arranged in an upper and lower interval, such as a gap of 2mm-3mm between the two.

[0166] The wireless power transmitting module 82 comprises a wireless power transmitting circuit board and a wireless power transmitting coil; and the wireless power receiving module 81 comprises a wireless power receiving circuit board and a wireless power receiving coil.

[0167] The wireless power transmitting circuit board drives the wireless power transmitting coil to generate an alternating magnetic field, the wireless power receiving coil generates an induced current, and the induced current generated is sent to the wireless power receiving circuit board, and the wireless power receiving circuit board processes the received induced current to power the first transmitter 11, the second transmitter 21, the optical receiver 14 and the control circuit.

[0168] When the laser radar is powered on, the wireless power transmission module 82 transmits the power supply in the lower shell 52 to the wireless power receiving module 81 through electromagnetic induction, and the wireless power receiving module 81 obtains power and transmits it to the laser ranging unit, the temperature drift detection unit, the control circuit, etc., and starts the ranging work.

[0169] The laser radar of the embodiment uses the control circuit to drive two emitters to work in time-sharing mode, obtains distance information on the same light receiver, and uses the internal fixed optical path to eliminate the temperature drift generated by the control circuit, thereby simply and efficiently eliminating and compensating the influence of temperature drift.

[0170] The temperature drift detection unit and the control circuit are used to calculate the temperature drift error signal, the laser ranging unit and the control circuit are used to calculate the distance to the target object, and then the temperature drift error signal is subtracted to obtain the ranging result after eliminating the temperature drift. The ranging result is sent to the main control unit (central processor) of the laser radar through the optical communication module. The motor rotates at a uniform speed according to the set speed, drives the structure 30 and the angle code disc 61 to rotate together, and through the start mark arranged on the angle code disc 61, the central processor of the laser radar can calculate the angle pointed to by the angle code disc 61 at the same time. The central processor integrates the ranging result obtained through the optical communication module and the angle result at the same time to obtain a bearing information, and in this way, the distance and angle information of the target object in the range of 360 degrees can be obtained after one rotation of the motor, and the basic function of the laser radar is completed.

[0171] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A laser radar, characterized in that: include: A laser ranging unit includes a first transmitter, a collimating lens, a receiving lens, and a light receiver; light emitted by the first transmitter passes through the collimating lens and then reaches a target object; light reflected from the target object enters the receiving lens; light converged by the receiving lens enters the light receiver; and the light receiver emits an electrical signal after receiving the light; a temperature drift detection unit comprising a second emitter and a reflecting surface; The light emitted by the second emitter is reflected by the reflective surface and then enters the light receiver; A control circuit comprising: a driving circuit, wherein a first driving output terminal thereof is connected to the first emitter, and a second driving output terminal thereof is connected to the second emitter; a timer for measuring a second timing time from when the second drive output terminal sends a drive signal to when the electrical signal sent by the optical receiver is received; and further for measuring a first timing time from when the first drive output terminal sends a drive signal to when the electrical signal sent by the optical receiver is received; A calculation circuit generates a temperature drift error signal according to the second timing time; calculates the distance to the target object according to the first timing time, and subtracts the temperature drift error signal to obtain the distance after eliminating the temperature drift.

2. The laser radar according to claim 1, wherein: The calculation circuit includes a first register, a second register, a third register, a fourth register, a first multiplier, a second multiplier, a first subtractor, and a second subtractor; The timer has a first input connected to the first trigger output of the driving circuit, a second input connected to the second trigger output of the driving circuit, a third input connected to the output of the optical receiver, a first output connected to the input of the first multiplier, and a second output connected to the input of the second multiplier; The first register is used to store the speed c of light in air; The second register is used to store the sum of the distance from the second transmitter to the reflecting surface and the distance from the reflecting surface to the light receiver; The second multiplier is configured to multiply the speed c in the first register by the second timing time t outputted from the second output terminal of the timer; the second subtractor is configured to subtract the sum of the distances in the second register from the product output by the second multiplier to obtain a temperature drift error signal; The third register is used to store the temperature drift error signal output by the second subtractor; The first multiplier is configured to multiply the speed c in the first register, the first timing time T outputted from the first output terminal of the timer, and the multiplier stored in the fourth register; The first subtractor is used to subtract the temperature drift error signal in the third register from the product output by the first multiplier to obtain the distance after the temperature drift is eliminated.

3. The laser radar according to claim 1, wherein: The optical path between the second emitter and the reflecting surface and the optical path between the receiving lens and the optical receiver are perpendicular to each other.

4. The laser radar according to claim 1, wherein: The laser radar further includes a structure having a first sleeve and a second sleeve arranged vertically; the first sleeve is located above the second sleeve; The first sleeve is arranged horizontally and has a front opening and a rear opening; the collimating lens is installed in the first sleeve and blocks the front opening of the first sleeve; the first emitter is located in the first sleeve and is close to the rear opening of the first sleeve; the first emitter is fixed to a transmitting circuit board and is electrically connected to the transmitting circuit board; the transmitting circuit board is electrically connected to a control board, the control circuit is arranged on the control board and is electrically connected to the control circuit, and the control board is fixed to the structure; The second sleeve is arranged horizontally and has a front opening and a rear opening; the receiving lens is installed in the second sleeve and blocks the front opening of the second sleeve; the optical receiver is located in the second sleeve and is close to the rear opening of the second sleeve; the optical receiver is fixed on a receiving circuit board and is electrically connected to the receiving circuit board; the receiving circuit board is electrically connected to the control board; The second emitter and the reflecting surface are arranged opposite to each other on the inner side wall of the second sleeve.

5. The laser radar according to claim 4, characterized in that: The inner diameter of the first sleeve gradually decreases from the front end opening to the rear end opening.

6. The laser radar according to claim 4, characterized in that: The second sleeve is provided with a first diameter-reducing section and a second diameter-reducing section in order from the front opening to the rear opening; The inner diameter of the first diameter-changing section gradually decreases from the front opening to the rear opening; The inner diameter of the second diameter-varying section gradually increases from the front opening to the rear opening; The receiving lens is located in the first diameter-changing section, and the light receiver is located in the second diameter-changing section; the second emitter and the reflecting surface are arranged opposite to each other on the inner side wall of the second diameter-changing section.

7. The laser radar according to claim 4, characterized in that: The housing of the laser radar includes an optical cover and a lower housing, wherein the optical cover is located above the lower housing and is detachably connected to the lower housing; The structure is located in the optical housing; The motor of the laser radar is located in the lower shell, and the stator of the motor is fixed to the lower shell, and the rotor of the motor is fixed to the structure, driving the structure to rotate.

8. The laser radar according to claim 7, characterized in that: The laser radar includes an angle code disk and a photoelectric encoder; The angle code disk is a circular ring structure, which is sleeved on the outside of the rotor of the motor, arranged coaxially with the rotor, and fixedly connected to the rotor; the top of the angle code disk has a tooth groove that cooperates with the photoelectric encoder; The photoelectric encoder is fixedly connected to the lower shell, detects the rotation angle of the rotor, and sends the detected angle signal to the main control unit of the laser radar.

9. The laser radar according to claim 7, characterized in that: The laser radar further includes an optical communication module, which includes an optical communication transmitting end and an optical communication receiving end; The optical communication transmitting end and the optical communication receiving end are arranged vertically in the hollow shaft of the motor; the optical communication receiving end transmits optical signals with the optical communication transmitting end; The optical communication transmitting end is electrically connected to the control circuit; the optical communication receiving end is electrically connected to the main control unit of the laser radar.

10. The laser radar according to claim 7, characterized in that: The laser radar further includes a wireless power receiving module and a wireless power transmitting module; The wireless power receiving module is sleeved on the outside of the rotor of the motor and is fixedly connected to the rotor; The wireless power transmission module is located below the wireless power receiving module and is fixedly connected to the lower housing; The wireless power transmission module generates an alternating magnetic field, and the wireless power receiving module generates an induced current to supply power to the first transmitter, the second transmitter, the optical receiver, and the control circuit.

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