Angle measurement device and method for scanning device, and laser radar

Abstract

The invention discloses an angle measurement device and method for a scanning device, and a laser radar. The angle measurement device comprises an LC oscillator, a driving circuit, an angle calculation module, and a temperature drift compensation module. The LC oscillator comprises an inductor unit and a capacitor unit, wherein the inductor unit and the capacitor unit are coupled between a first node and a second node in parallel; the driving circuit is configured to drive the LC oscillator to oscillate; the temperature drift compensation module is configured to adjust an oscillation parameter of the LC oscillator so as to compensate the temperature drift of the oscillation parameter; the angle calculation module is configured to obtain oscillation parameters of the LC oscillator and determine the deflection angle of the scanning device according to the oscillation parameters of the LC oscillator. By using the scheme of the invention, the influence of temperature change on an angle measurement result can be reduced, and the angle measurement accuracy is improved.

Description

Technical Field

[0001] The present invention relates to the field of circuit technology, and in particular to an angle measurement device and method for a scanning device, and a laser radar. Background Art

[0002] During operation, scanning lidar needs to measure the rotation or swing angle of the scanning device to determine the spatial angular position of each detection beam when it encounters a target object. These spatial angular positions are combined with the target distance calculated based on the flight time to determine the three-dimensional spatial position of the target object.

[0003] In order to improve the accuracy of laser radar measurement, it is necessary to accurately measure the rotation or swing angle of the scanning device. An existing measurement scheme is to use eddy current coils and LC resonance systems to achieve angle measurement. By measuring the oscillation parameters of the LC resonance system, the rotation or swing angle of the scanning device is calculated. When the ambient temperature changes, the oscillation parameters of the LC resonance system will drift with the temperature, and the rotation or swing angle measurement value of the scanning device will also drift with the temperature, resulting in a decrease in measurement accuracy. Since the ambient temperature range of laser radar operation is large, a device and method for accurately measuring the angle of the laser radar scanning device in a wide temperature range is needed. Summary of the invention

[0004] The embodiments of the present invention provide an angle measurement device and method for a scanning device, and a laser radar, so as to reduce the influence of temperature change on the angle measurement result and improve the accuracy of angle measurement.

[0005] In one aspect, an embodiment of the present invention provides an angle measurement device for a scanning device, the angle measurement device comprising: an LC oscillator, a driving circuit, an angle calculation module, and a temperature drift compensation module; the LC oscillator comprises: an inductor unit and a capacitor unit, the inductor unit and the capacitor unit are coupled in parallel between a first node and a second node;

[0006] The driving circuit is configured to drive the LC oscillator to oscillate;.

[0007] The temperature drift compensation module is configured to adjust the oscillation parameters of the LC oscillator to compensate for the temperature drift of the oscillation parameters;

[0008] The angle calculation module is configured to obtain the oscillation parameters of the LC oscillator and determine the deflection angle of the scanning device according to the oscillation parameters of the LC oscillator.

[0009] Optionally, the driving circuit includes: a cross-coupling circuit and a power supply;

[0010] The power supply is configured to supply power to the cross-coupling circuit;

[0011] The cross-coupled circuit includes any one of the following: a cross-coupled NMOS oscillator, a cross-coupled PMOS oscillator, and a complementary oscillator composed of PMOS and NMOS.

[0012] Optionally, the cross-coupling circuit is coupled to the first node and the second node of the LC oscillation circuit respectively.

[0013] Optionally, the power supply comprises an adjustable power supply;

[0014] The temperature drift compensation module adjusts the oscillation parameters by adjusting the size of the adjustable power supply.

[0015] Optionally, the adjustable power supply includes an adjustable voltage source or an adjustable current source.

[0016] Optionally, the capacitor in the LC oscillator includes an adjustable capacitor;

[0017] The temperature drift compensation module adjusts the oscillation parameter by adjusting the value of the adjustable capacitor.

[0018] Optionally, the capacitor in the LC oscillator comprises a MOS variable capacitor;

[0019] The temperature drift compensation module provides a bias voltage value adapted to compensate for the temperature drift of the oscillation parameter to the MOS variable capacitor.

[0020] Optionally, the temperature drift compensation module is configured to adjust the adjustable power supply or the adjustable capacitor according to the current temperature and calibration information.

[0021] Optionally, the calibration information includes any one or more of the following: a temperature-current value data table, a temperature-current value curve, a temperature-voltage value data table, a temperature-voltage value curve, a temperature-capacitance value data table, a temperature-capacitance value curve.

[0022] Optionally, the temperature drift compensation module determines a current value, a voltage value, or a capacitance value corresponding to a current temperature according to the calibration information, and adjusts the adjustable power supply or the adjustable capacitor according to the current value, the voltage value, or the capacitance value.

[0023] Optionally, the temperature drift compensation module is configured to adjust the adjustable power supply or the adjustable capacitor according to the oscillation parameters at a preset temperature and a preset deflection angle.

[0024] Optionally, the oscillation parameter includes: an oscillation frequency, or an equivalent inductance value formed by the inductance unit and a conductive reference object disposed on the scanning device.

[0025] On the other hand, an embodiment of the present invention further provides an angle measurement method for a scanning device, the method comprising:

[0026] The driving circuit drives the LC oscillator to oscillate, and the temperature drift of the oscillation parameter is compensated by adjusting the oscillation parameter of the LC oscillator; the LC oscillator includes an inductor unit and a capacitor unit;

[0027] An oscillation parameter of the LC oscillator is obtained, and a deflection angle of the scanning device is determined according to the oscillation parameter of the LC oscillator.

[0028] Optionally, the driving circuit includes a cross-coupling circuit and a power supply.

[0029] Optionally, the power supply comprises an adjustable power supply;

[0030] The compensating the temperature drift of the oscillation parameter by adjusting the oscillation parameter of the LC oscillator comprises:

[0031] The oscillation parameters are adjusted by adjusting the size of the adjustable power supply.

[0032] Optionally, the capacitor in the LC oscillator includes an adjustable capacitor;

[0033] The compensating the temperature drift of the oscillation parameter by adjusting the oscillation parameter of the LC oscillator comprises:

[0034] The oscillation parameter is adjusted by adjusting the value of the adjustable capacitor.

[0035] Optionally, the capacitor in the LC oscillator comprises a MOS variable capacitor;

[0036] The compensating the temperature drift of the oscillation parameter by adjusting the oscillation parameter of the LC oscillator comprises:

[0037] A bias voltage value adapted to compensate for the temperature drift of the oscillation parameter is provided to the MOS variable capacitor.

[0038] Optionally, compensating for the temperature drift of the oscillation parameter by adjusting the oscillation parameter of the LC oscillator includes: adjusting the adjustable power supply or the adjustable capacitor according to the current temperature and calibration information.

[0039] Optionally, the calibration information includes any one or more of the following: a temperature-current value data table, a temperature-current value curve, a temperature-voltage value data table, a temperature-voltage value curve, a temperature-capacitance value data table, a temperature-capacitance value curve.

[0040] Optionally, adjusting the adjustable power supply or the adjustable capacitor according to the current temperature and calibration information includes:

[0041] Determine the current value, voltage value or capacitance value corresponding to the current temperature according to the calibration information;

[0042] The adjustable power supply or the adjustable capacitor is adjusted according to the current value or the voltage value or the capacitance value.

[0043] Optionally, compensating for the temperature drift of the oscillation parameters by adjusting the oscillation parameters of the LC oscillator includes: adjusting the adjustable power supply or the adjustable capacitor according to the inductance value of the inductance unit at a preset temperature and deflection angle or the oscillation parameters at a preset temperature and a preset deflection angle.

[0044] Optionally, the oscillation parameter includes: an oscillation frequency, or an equivalent inductance value formed by the inductance unit and a conductive reference object disposed on the scanning device.

[0045] On the other hand, an embodiment of the present invention further provides a laser radar, the laser radar comprising a scanning device and the angle measuring device for the scanning device as described above;

[0046] The scanning device is provided with a conductive reference object;

[0047] The inductance unit in the angle measuring device is installed toward the conductive reference object.

[0048] Optionally, the scanning device comprises a galvanometer or a rotating mirror.

[0049] The angle measurement device and method for a scanning device and a laser radar provided in an embodiment of the present invention measure the oscillation frequency of an LC oscillator, calculate the inductance value of the inductance formed by the scanning device and the external coil, and then calculate the deflection angle of the scanning device. In view of the problem that the oscillation phase of the LC oscillator driving circuit changes with temperature, so that the inductance measurement value changes with temperature, thereby causing the angle measurement to have a temperature effect, the scheme of the present invention compensates for the temperature drift of the oscillation parameter by adjusting the oscillation parameter of the LC oscillator, that is, when the temperature changes, by adjusting the oscillation parameter of the LC oscillator, the oscillation frequency of the LC oscillator remains unchanged, avoiding the influence of temperature changes on the deflection angle measurement result, and ensuring the accuracy of the measurement result.

[0050] Furthermore, different parameters in the driving circuit can be adjusted in a variety of ways, which enhances the flexibility of the solution and facilitates its use in different application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0052] Figure 1 It is a schematic diagram of the principle of a device for measuring the rotation or swing angle of a galvanometer;

[0053] Figure 2 yes Figure 1 Equivalent circuit diagram of the measuring device shown;

[0054] Figure 3 It is a schematic diagram of the relationship between the eddy current coils and the galvanometer provided at both ends of the galvanometer;

[0055] Figure 4 It is a structural schematic diagram of an existing LC resonant circuit;

[0056] Figure 5 yes Figure 4 A schematic diagram of the voltage change waveforms of the comparator output voltage Vout and the voltage at both ends of the LC oscillator in the circuit shown;

[0057] Figure 6 is a structural schematic diagram of an angle measuring device for a scanning device provided by an embodiment of the present invention;

[0058] Figure 7 yes Figure 6 A schematic diagram of a structure of an LC oscillator in an angle measuring device for a scanning device is shown;

[0059] Figure 8 yes Figure 6 A schematic diagram of a structure of a driving circuit and an LC oscillator;

[0060] Fig. 9 yes Figure 6 Another structural diagram of the driving circuit and LC oscillator;

[0061] Fig.10 yes Figure 6 Another structural diagram of the driving circuit and LC oscillator;

[0062] Fig.11 yes Figure 6 Another structural diagram of the driving circuit and LC oscillator;

[0063] Fig.12 yes Fig.10 Schematic diagram of the use of an adjustable power supply in the driving circuit;

[0064] Fig.13 yes Fig.10 Schematic diagram of the use of adjustable capacitors in the LC oscillator;

[0065] Fig.14 yes Fig.10 Schematic diagram of LC oscillator including MOS variable capacitor;

[0066] Fig.15 is a flow chart of an angle measurement method for a scanning device provided by an embodiment of the present invention;

[0067] Fig.16 is a schematic diagram of the structure of a laser radar provided by an embodiment of the present invention;

[0068] Fig.17 yes Fig.16 A schematic structural diagram of an angle measurement device in a laser radar is shown. DETAILED DESCRIPTION

[0069] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0070] like Figure 1 The figure shows a schematic diagram of the rotation or swing angle of a galvanometer and the principle of the measuring device. Figure 2 is its equivalent circuit diagram.

[0071] Also refer to Figure 1 and Figure 2 , a reference object 11 is installed on the main body of the galvanometer 10. The reference object 11 needs to have good conductivity, such as metal material (aluminum, copper, etc.); an eddy current coil 21 is installed on the fixed reference part 20, and the eddy current coil 21 faces the reference object 11. The eddy current coil 21 is connected in parallel with a capacitor 22 to form an LC resonant system. Through the excitation circuit, the LC resonant system always works at the resonant point. Resonant frequency Where C is the capacitance value and L is the equivalent inductance value of the LC resonant system.

[0072] Figure 1 The measurement device shown can be equivalent to Figure 2 As shown in the circuit diagram, the reference object 11 is equivalent to an inductor-resistor model, and the mutual inductance between the reference object 11 and the eddy current coil is modulated by the distance d between the reference object 11 and the eddy current coil 21. Therefore, the distance d between the reference object 11 and the eddy current coil 21 will affect the value of the equivalent inductance L in the LC resonant system, and further, the resonant frequency f of the LC resonant system. Therefore, by measuring the resonant frequency f (or the period 1 / f), the distance d between the reference object 11 and the eddy current coil 21 can be obtained, and then the rotation or swing angle of the galvanometer can be calculated according to the distance d.

[0073] like Figure 3As shown, when measuring, eddy current coils corresponding to conductive reference objects are respectively set at both ends of the galvanometer. By using inductance digital converters LDC1 and LDC2, the distances d1 and d2 between the reference objects at both ends of the galvanometer and the eddy current coils can be measured during the rotation or swinging of the galvanometer. Then, according to the distance d0 between the galvanometer and the coil when the galvanometer is stationary or the spacing x between the eddy current coils, the changes in the distances △d1 and △d2 at both ends of the galvanometer can be calculated, and then the deflection angle θ of the galvanometer can be calculated based on the changes.

[0074] In the scheme of realizing angle measurement using eddy current coil and LC resonance system, an excitation circuit is required to drive the LC oscillator composed of eddy current coil and inductor to produce oscillation and maintain the damping loss of the LC oscillator. To this end, the excitation circuit needs to output a driving signal with stable frequency and amplitude to the LC oscillator.

[0075] like Figure 4 As shown, an excitation circuit based on an LC oscillator is provided. The excitation circuit includes: a resonance unit 41, an excitation unit 42, and a feedback unit. Among them, the resonance unit 41 includes an inductor L and a capacitor C, the excitation unit 42 includes an NMOS tube M1, and the feedback unit includes a comparator U1 and a feedback resistor R1.

[0076] Among them, the resistor R2 and the resistor R3 are the comparator input resistors. The resistors R2 and R3 can increase the input impedance of the comparator U1, reduce the influence of the input resistance of the comparator U1 and the input parasitic capacitance on the LC resonance, and prevent the comparator from being damaged due to input overvoltage.

[0077] The resistor R4 is a current-limiting resistor, which is configured to limit the charging current of the excitation unit 42 to avoid damage to the device due to excessive charging current during the oscillation process.

[0078] Comparator U1 output voltage V out The waveform of the voltage change at both ends of the LC oscillator is as follows Figure 5 shown.

[0079] Figure 4 The LC resonant circuit shown is not ideal and its oscillation phase It will change with temperature. When the temperature changes from temp0 to temp1, the phase change will cause the frequency to change. The phase change can be calculated using the following formula:

[0080]

[0081] Among them, ω0 represents the oscillation frequency at temperature temp0, Δω and They respectively represent the changes in oscillation frequency and oscillation phase when the temperature changes from temp0 to temp1, and Q represents the quality factor of the inductor.

[0082] For the equivalent inductance L between the reference object and the eddy current coil, since its quality factor is low (Q is usually around 20), the oscillation phase change caused by temperature change has a greater impact on the oscillation frequency.

[0083] exist Figure 4 In the LC resonant circuit shown, the magnitude of its phase temperature drift mainly depends on the delay of the comparator U1. The delay of the comparator U1 is usually about 10ns. The delay value will fluctuate from several to tens of ns as the temperature changes. Therefore, at different temperatures, the delay value of the comparator U1 fluctuates, which will cause the phase of the LC oscillator to change, affecting the magnitude of the oscillation frequency, and further affecting the accuracy of the angle measurement.

[0084] In the scheme of realizing angle measurement by using eddy current coil and LC resonant system, an excitation circuit is required to drive the LC oscillator composed of eddy current coil and inductor to generate oscillation and maintain the damping loss of the LC oscillator. In view of the problem that the existing excitation circuit affects the angle measurement accuracy due to the existence of temperature drift, the embodiment of the present invention provides an angle measurement device and method for a scanning device, and a laser radar, which uses a cross-coupled NMOS pair and a PMOS pair to form an equivalent negative resistance to provide the LC oscillator with the energy required for oscillation. The driving circuit is directly formed on the chip through a semiconductor process, and the influence of temperature changes on the galvanometer angle measurement results is reduced by implementing on-chip modulation.

[0085] like Figure 6 FIG. 1 is a schematic diagram of a structure of an angle measuring device for a scanning device provided in an embodiment of the present invention.

[0086] The angle measurement device includes: an LC oscillator 601, a driving circuit 602, an angle calculation module 603, and a temperature drift compensation module 604. In this embodiment, the functions of each module are as follows:

[0087] The driving circuit 602 is configured to drive the LC oscillator 601 to oscillate;

[0088] The temperature drift compensation module 604 is configured to adjust the oscillation parameters of the LC oscillator 601 to compensate for the temperature drift of the oscillation parameters; the oscillation parameters include: oscillation frequency, or an equivalent inductance value formed by the inductance unit and a conductive reference disposed on the scanning device.

[0089] The angle calculation module 603 is configured to obtain the oscillation parameters of the LC oscillator 601 , and determine the deflection angle of the scanning device according to the oscillation parameters of the LC oscillator 601 .

[0090] Figure 7Schematic diagram of a structure of the LC oscillator 601 in the above-mentioned angle measurement device. The LC oscillator 601 includes: an inductor unit L and a capacitor unit C. The inductor unit L and the capacitor unit C are coupled in parallel between a first node A and a second node B.

[0091] In a non-limiting embodiment, the driving circuit 602 includes a cross-coupled circuit and a power supply. The power supply may be a current source or a voltage source, configured to supply power to the cross-coupled circuit; the cross-coupled circuit may include but is not limited to any one of the following: a cross-coupled NMOS oscillator, a cross-coupled PMOS oscillator, and a complementary oscillator composed of a PMOS and an NMOS.

[0092] In the following embodiments, the power source is taken as an example for description.

[0093] like Figure 8 In a structural example of the driving circuit 602 shown, the cross-coupling circuit includes two cross-coupled NMOS tubes NM1 and NM2, the drain of NM1 is connected to the gate of NM2, and is connected to the first node A of the LC oscillator 601, the drain of NM2 is connected to the gate of NM1, and is connected to the second node B of the LC oscillator 601, the connection end of the two inductors is connected to the voltage VDD, and the source of NM1 and the source of NM2 are connected to the power supply Is.

[0094] like Fig. 9 In another structural example of the driving circuit 602 shown, the cross-coupling circuit includes two cross-coupled PMOS tubes PM1 and PM2, the drain of PM1 is connected to the gate of PM2 and to the first node A of the LC oscillator 601, the drain of PM2 is connected to the gate of PM1 and to the second node B of the LC oscillator 601, the source of PM1 and the source of PM2 are connected to the power supply Is, and the connection ends of the two inductors are grounded.

[0095] Figure 8 and Fig. 9 The driving circuit shown uses the cross-coupling of NMOS or PMOS to provide negative impedance to compensate for the energy consumed during the oscillation of the LC loop. This type of circuit can be directly integrated on a chip through semiconductor technology, which is conducive to the integration of equipment.

[0096] like Fig.10In another structural example of the driving circuit 602 shown in the figure, the cross-coupling circuit includes a complementary oscillator composed of PMOS and NMOS, that is, two PMOS transistors PM1 and PM2, and two NMOS transistors NM1 and NM2, wherein the gate of PM1 is connected to the gate of NM1 and to the second node B of the LC oscillator 601; the gate of PM2 is connected to the gate of NM2 and to the first node A of the LC oscillator 601; the source of PM1 is connected to the source of PM2 and to the power supply Is; the source of NM1 is connected to the source of NM2 and to ground. The drain of PM1 is connected to the drain of NM1, and the drain of PM2 is connected to the drain of NM2.

[0097] like Fig.11 In another structural example of the driving circuit 602 shown in FIG. Fig.10 The example shown differs in that Fig.11 The power supply in is connected to the source of NM1 and NM2, and the source of PM1 and PM2 is connected to the voltage VDD.

[0098] Compared to Figure 8 and Fig. 9 The driving circuit shown, Fig.10 and Fig.11 The driving circuit shown uses a complementary oscillator, which can provide higher negative impedance and effectively reduce power consumption.

[0099] Of course, in a specific application, the driving circuit 602 may also have other various deformation structures, which is not limited in the embodiment of the present invention.

[0100] Above Figures 8 to 11 In the illustrated embodiment, the voltages of the first node A and the second node B of the LC oscillator 601 are VDD. When the LC oscillator 601 starts oscillating, the voltage waveforms at the first node A and the second node B are sinusoidal waves with the voltage VDD as the DC component, and the oscillation frequency is:

[0101]

[0102] Temperature changes will cause changes in the oscillation phase, and changes in the oscillation phase will cause changes in the oscillation frequency. Figure 6 In the angle measurement device provided by the embodiment of the present invention, the oscillation parameters of the LC oscillator 601 are adjusted by the temperature drift compensation module 604 to compensate for the temperature drift of the oscillation parameters. That is, by adjusting the oscillation parameters of the LC oscillator 601, the oscillation frequency of the oscillation waveform output by the LC oscillator 601 is kept constant.

[0103] In a non-limiting embodiment, Fig.12 As shown, the power supply Is in the LC oscillator 601 is an adjustable power supply. Accordingly, Figure 6 The temperature drift compensation module 604 in the adjustable power supply adjusts the oscillation parameters by adjusting the size of the adjustable power supply, so that the oscillation frequency of the oscillation waveform outputted by the adjustable power supply remains constant. Similarly, the adjustable power supply includes an adjustable voltage source or an adjustable current source. The adjustable power supply is also applicable to Fig.11 The driving circuit in the embodiment shown.

[0104] In another non-limiting embodiment, Fig.13 As shown, the capacitor C in the LC oscillator 601 can be an adjustable capacitor. Accordingly, Figure 6 The temperature drift compensation module 604 in the embodiment adjusts the value of the adjustable capacitor to adjust the oscillation parameters so that the oscillation frequency of the oscillation waveform outputted by the adjustable capacitor remains constant. Fig.11 The driving circuit in the embodiment shown.

[0105] In practical applications, Figure 6 The temperature drift compensation module 604 in the embodiment can use a variety of methods to determine the parameter value that needs to be adjusted. For example:

[0106] In a non-limiting embodiment, the adjustment parameters required at different temperatures can be calibrated in advance to generate calibration information. The calibration information can include but is not limited to any one or more of the following: a temperature-current value data table, a temperature-current value curve, a temperature-voltage value data table, a temperature-voltage value curve, a temperature-capacitance value data table, and a temperature-capacitance value curve.

[0107] During calibration, let the starting temperature be temp1. At the starting temperature temp1, record the oscillation frequency value output by the LC oscillator or the value of the inductance L calculated based on the oscillation frequency value when the deflection angle θ of the scanning device takes a specific value (for example, θ=0, that is, the scanning device is not powered on for deflection). Then, adjust the temperature value, record the inductance value or oscillation frequency value at different temperature values ​​and the same angle, and adjust the current of the driving circuit (the current source is an adjustable current source) or the capacitance value of the LC oscillator (the capacitor is an adjustable capacitor), adjust the value of the inductance L or the oscillation frequency value to the inductance value or the oscillation frequency value at the temperature temp1, and record the current value or capacitance value corresponding to different temperature values. Traverse the entire temperature range (such as -20 to 120°C) to obtain the calibration information.

[0108] Accordingly, the temperature drift compensation module 604 can detect the current temperature in real time and adjust the adjustable power supply or the adjustable capacitor according to the current temperature and calibration information. For example, the current value, voltage value, or capacitance value corresponding to the current temperature can be determined according to the calibration information, and then the value of the adjustable power supply or adjustable capacitor can be determined according to the current value, voltage value, or capacitance value corresponding to the current temperature, and the adjustable power supply or adjustable capacitor can be adjusted to the corresponding value.

[0109] The temperature drift compensation module 604 uses the calibration information to adjust the current value of the driving circuit or the capacitance value of the LC oscillator in real time according to the current temperature, thereby compensating for the influence of temperature drift on the angle measurement result. This method has high compensation accuracy and small amount of calculation.

[0110] Further, considering that the frequency of temperature change (on the order of a few tenths of Hz) is very slow relative to the frequency of change of the deflection angle θ of the scanning device (corresponding to the scanning rate of the galvanometer, on the order of several hundred Hz), it can be considered that the temperature change in one scanning cycle of the scanning device can be ignored. Therefore, in another non-limiting embodiment, the temperature drift compensation module 604 can adjust the corresponding parameters only when the deflection angle θ is a specific value each time (such as θ=0, that is, the scanning device is not powered on for deflection), that is, the temperature drift compensation module 604 can only adjust the adjustable power supply or the adjustable capacitor according to the oscillation parameters at the preset temperature and the preset deflection angle (such as room temperature 25°C, θ=0) each time the deflection angle θ is a specific value (such as θ=0, that is, the scanning device is not powered on for deflection), so that the output oscillation parameters are equal to the oscillation parameters at the above preset temperature and the preset deflection angle. This adjustment method does not require the setting of a temperature monitoring module, nor does it require real-time monitoring of temperature changes. It only needs to feedback and adjust the circuit parameters, that is, the value of the adjustable power supply or adjustable capacitor, according to the inductance or oscillation frequency at a specific temperature and deflection angle, which can also achieve the purpose of temperature drift compensation.

[0111] In another non-limiting embodiment, the characteristics of MOS variable capacitors may be used to compensate for temperature drift.

[0112] The capacitance value of a MOS variable capacitor changes with the voltage value applied to the MOS variable capacitor, and when the bias value Vtune is constant, the MOS variable capacitor also has different capacitance values ​​at different temperatures. Under certain bias values ​​Vtune, its capacitance value is positively correlated with the temperature value, that is, the higher the temperature, the higher the capacitance value. Under certain bias values ​​Vtune, its capacitance value is negatively correlated with the temperature value, that is, the lower the temperature, the higher the capacitance value. Under certain bias values ​​Vtune, its capacitance value is not highly correlated with the temperature value, that is, the capacitance value is basically equal at different temperatures.

[0113] By utilizing the above properties of the MOS variable capacitor and applying a suitable bias value Vtune to it, the capacitance value will show a negative correlation with the temperature value, which can offset the temperature drift of other devices in the cross-coupling circuit and minimize the change of the oscillation frequency output by the LC oscillator with temperature (for example, <1ppm / ℃), thereby ensuring that the angle measurement result is minimally affected by temperature.

[0114] Accordingly, if Fig.14 As shown, in this example, the capacitor unit in the LC oscillator 601 includes a fixed capacitor C and two MOS variable capacitors Cmos-var connected in series. Accordingly, the temperature drift compensation module 604 provides a bias value Vtune adapted to compensate for the temperature drift of the oscillation parameter to the MOS variable capacitor. The bias value adapted to different temperatures can be obtained by actual measurement based on the parameters of the MOS variable capacitor.

[0115] The temperature drift compensation method of this embodiment does not require feedback control or pre-calibration, and only requires reasonable setting of the bias voltage of the MOS variable capacitor to effectively reduce the overall temperature drift of the LC oscillator.

[0116] The angle measuring device for a scanning device provided by an embodiment of the present invention measures the oscillation frequency of an LC oscillator, calculates the mutual inductance value of the inductance formed by the scanning device and the external coil, and then calculates the deflection angle of the scanning device. In view of the problem that the oscillation phase of the LC oscillator driving circuit changes with temperature, so that the inductance value changes with temperature, thereby causing the angle measurement to have a temperature effect, the solution of the present invention compensates for the temperature drift of the oscillation parameter by adjusting the oscillation parameter of the LC oscillator, that is, when the temperature changes, by adjusting the oscillation parameter of the LC oscillator, the oscillation frequency of the LC oscillator remains unchanged, thereby avoiding the influence of temperature changes on the deflection angle measurement result, and ensuring the accuracy of the measurement result.

[0117] Accordingly, an embodiment of the present invention further provides an angle measurement method for a scanning device, such as Fig.15 As shown, it is a flow chart of the method, comprising the following steps:

[0118] In step 141, the driving circuit drives the LC oscillator to oscillate, and the temperature drift of the oscillation parameter is compensated by adjusting the oscillation parameter of the LC oscillator; the LC oscillator includes an inductor unit and a capacitor unit;

[0119] In step 142, the oscillation parameters of the LC oscillator are acquired, and the deflection angle of the scanning device is determined according to the oscillation parameters of the LC oscillator.

[0120] The oscillation parameters include: an oscillation frequency, or an equivalent inductance value formed by the inductance unit and a conductive reference object disposed on the scanning device.

[0121] Wherein, the driving circuit includes a cross-coupling circuit and a power supply. Accordingly, in specific applications, a variety of methods can be used to achieve compensation for the temperature drift of the oscillation parameters. For example:

[0122] In a non-limiting embodiment, the power supply includes an adjustable power supply. Accordingly, the oscillation parameter can be adjusted by adjusting the size of the adjustable power supply.

[0123] In another non-limiting embodiment, the capacitor in the LC oscillator includes an adjustable capacitor. Accordingly, the oscillation parameter can be adjusted by adjusting the value of the adjustable capacitor.

[0124] The above-mentioned adjustable power supply and adjustable capacitor can be adjusted in a variety of ways. For example, the adjustable power supply or the adjustable capacitor can be adjusted according to the current temperature and calibration information, and the calibration information includes but is not limited to any one or more of the following: temperature-current value data table, temperature-current value curve, temperature-voltage value data table, temperature-voltage value curve, temperature-capacitance value data table, temperature-capacitance value curve. In other words, the current value or voltage value or capacitance value corresponding to the current temperature is determined according to the calibration information, and then the adjustable power supply or adjustable capacitor is adjusted according to the current value or voltage value or capacitance value. For another example, the adjustable power supply or the adjustable capacitor can also be adjusted according to the inductance value of the inductance unit at a preset temperature and deflection angle or the oscillation parameters at a preset temperature and a preset deflection angle.

[0125] In another non-limiting embodiment, the capacitor in the LC oscillator comprises a MOS variable capacitor. Accordingly, a bias voltage value adapted to compensate for the temperature drift of the oscillation parameter can be provided to the MOS variable capacitor.

[0126] The angle measurement method for a scanning device provided by the embodiment of the present invention adjusts the oscillation parameters of the LC oscillator to compensate for the temperature drift of the oscillation parameters, thereby avoiding the influence of temperature changes on the deflection angle measurement results and ensuring the accuracy of the measurement results. Moreover, the adjustment methods are flexible and diverse, and are easy to use in different application scenarios.

[0127] Accordingly, an embodiment of the present invention further provides a laser radar, such as Fig.16 The figure shows a schematic diagram of the structure of the laser radar.

[0128] The laser radar 150 includes a scanning device 151 and the angle measuring device 152 used for the scanning device as described above.

[0129] A conductive reference object is provided on the scanning device 151 . For example, the scanning device 151 includes a scanning mirror 1510 , on which a reference object 1511 is mounted. The reference object 1511 should have good conductivity, such as metal material (aluminum, copper, etc.).

[0130] The inductance unit 1521 in the angle measuring device 152 is installed toward the conductive reference object.

[0131] Wherein, the scanning device 151 may include a galvanometer or a rotating mirror. Figure 3 As shown in the working principle, when measuring, the angle measuring device 152 can measure the distance between the reference object at one end or both ends of the galvanometer or rotating mirror and the inductance unit 1521, and the angle of the galvanometer or rotating mirror can be calculated based on the distance.

[0132] like Fig.17 As shown, Fig.16 A schematic structural diagram of an angle measurement device in a laser radar is shown.

[0133] In this embodiment, the above-mentioned LC oscillator + driving circuit + temperature drift compensation module is respectively set at both ends of the galvanometer or the rotating mirror, and for the convenience of description, it is referred to as the first module 161 and the second module 162. The measurement values ​​output by the first module 161 and the second module 162 are quantized by TDC (Time To Digital Convertor) 1 and TDC2 respectively, and the angle calculation module 163 inputs the quantization results of the two TDCs. The oscillation frequency f1 of the LC oscillator in the first module 161 and the oscillation frequency f2 of the LC oscillator in the second module 162 are calculated according to the quantization results of the TDC, and the values ​​of the inductances L1 and L2 are calculated according to the LC oscillation frequencies f1 and f2; the distances from the two ends of the galvanometer or the swing mirror to the coil are derived according to the values ​​of the inductances L1 and L2. The deflection angle θ of the galvanometer or the swing mirror can be calculated according to these two distance information.

[0134] Combine the following Fig.17 The calculation method of the deflection angle θ of the galvanometer or the swing mirror by the angle calculation module 163 and the compensation process for the temperature drift are described in detail.

[0135] The deflection angle θ is a two-dimensional function of time and temperature, i.e. θ(time, temp).

[0136] Assume the starting temperature is temp1, θ(temp1) = f(L1(temp1), L2(temp1));

[0137] When θ(temp1)=0, L1(temp1) and L2(temp1) and / or the corresponding oscillation frequency values ​​are recorded in the register.

[0138] In one adjustment method, the current temperature is monitored in real time. When the current temperature is temp2, θ(temp2)=f(L1(temp2), L2(temp2));

[0139] Due to the influence of temperature drift, when θ(temp2)=0, L1(temp2)≠L1(temp1), L2(temp2)≠L2(temp1), so adjust the current or voltage of the driving circuit (that is, adjust through the adjustable power supply) or adjust the capacitance value of the LC oscillator (when the capacitor is an adjustable capacitor) until L1(temp2)=L1(temp1), L2(temp2)=L2(temp1).

[0140] Correspondingly, since L1(temp2)=L1(temp1), L2(temp2)=L2(temp1), that is, at different temperatures, when the deflection angle of the galvanometer or the swing mirror is the same, the oscillation circuit outputs the same oscillation frequency value. It can be seen that through the above adjustment, the deflection angle θ is not affected by temperature changes and is only related to the deflection time of the galvanometer or the swing mirror. Therefore, the oscillation frequencies of the two LC oscillators can be calculated by the quantization results output by TDC1 and TDC2, respectively, and then the values ​​of the inductors L1 and L2 to be measured can be calculated. According to the inductors L1 and L2, the distances d1 and d2 between the inductors L1 and L2 and the galvanometer or the swing mirror can be calculated, and then the deflection angle θ of the galvanometer or the swing mirror can be calculated according to the distances d1 and d2.

[0141] In another adjustment method, there is no need to detect the current temperature in real time, but to take a specific value (such as θ = 0) at the deflection angle θ, and check whether the inductances L1 and L2 to be tested are the same as L1(temp1) and L2(temp1). If they are not the same, the current or voltage of the driving circuit or the capacitance value of the LC oscillator is adjusted until L1(temp) = L1(temp1), L2(temp) = L2(temp1) to compensate for the temperature drift caused by the temperature drift on the oscillation parameters of the LC oscillator, so that the deflection angle θ is not affected by temperature changes and is only related to the deflection time of the galvanometer or the swing mirror. Accordingly, the method for calculating the deflection angle θ of the galvanometer or the swing mirror is the same as above, and will not be repeated here.

[0142] It can be seen that by utilizing the solution of the present invention, the influence of temperature changes on the angle measurement results of the scanning device in the laser radar can be effectively reduced, the accuracy of the angle measurement can be improved, and the performance of the laser radar can be guaranteed.

[0143] It should be understood that the term "and / or" in this article is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article indicates that the associated objects before and after are in an "or" relationship.

[0144] The “plurality” mentioned in the embodiments of the present invention refers to two or more than two.

[0145] The first, second, etc. descriptions appearing in the embodiments of the present invention are only used for illustration and distinction of the description objects. There is no order, nor does it indicate any special limitation on the number of devices in the embodiments of the present invention, and cannot constitute any limitation on the embodiments of the present invention.

[0146] The “connection” in the embodiments of the present invention refers to various connection modes such as direct connection or indirect connection to achieve communication between devices, and the embodiments of the present invention do not impose any limitation on this.

[0147] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. An angle measuring device for a scanning device, characterized in that: The angle measurement device comprises: an LC oscillator, a driving circuit, an angle calculation module, and a temperature drift compensation module; the LC oscillator comprises: an inductor unit and a capacitor unit, the inductor unit and the capacitor unit are coupled in parallel between a first node and a second node; The driving circuit is configured to drive the LC oscillator to oscillate;. The temperature drift compensation module is configured to adjust the oscillation parameters of the LC oscillator to compensate for the temperature drift of the oscillation parameters; The angle calculation module is configured to obtain the oscillation parameters of the LC oscillator and determine the deflection angle of the scanning device according to the oscillation parameters of the LC oscillator.

2. The angle measuring device for a scanning device according to claim 1, characterized in that: The driving circuit includes: a cross-coupling circuit and a power supply; The power supply is configured to supply power to the cross-coupling circuit; The cross-coupled circuit includes any one of the following: a cross-coupled NMOS oscillator, a cross-coupled PMOS oscillator, and a complementary oscillator composed of PMOS and NMOS.

3. The angle measuring device for a scanning device according to claim 2, characterized in that: The cross-coupling circuit is coupled to the first node and the second node of the LC oscillation circuit, respectively.

4. The angle measuring device for a scanning device according to claim 2, characterized in that: The power supply includes an adjustable power supply; The temperature drift compensation module adjusts the oscillation parameters by adjusting the size of the adjustable power supply.

5. The angle measuring device for a scanning device according to claim 4, characterized in that: The adjustable power supply includes an adjustable voltage source or an adjustable current source.

6. The angle measuring device for a scanning device according to claim 2, characterized in that: The capacitor in the LC oscillator includes an adjustable capacitor; The temperature drift compensation module adjusts the oscillation parameter by adjusting the value of the adjustable capacitor.

7. The angle measuring device for a scanning device according to claim 2, characterized in that: The capacitor in the LC oscillator includes a MOS variable capacitor; The temperature drift compensation module provides a bias voltage value adapted to compensate for the temperature drift of the oscillation parameter to the MOS variable capacitor.

8. The angle measuring device for a scanning device according to claim 4, 5 or 6, characterized in that: The temperature drift compensation module is configured to adjust the adjustable power supply or the adjustable capacitor according to the current temperature and calibration information.

9. The angle measuring device for a scanning device according to claim 8, characterized in that: The calibration information includes any one or more of the following: a temperature-current value data table, a temperature-current value curve, a temperature-voltage value data table, a temperature-voltage value curve, a temperature-capacitance value data table, and a temperature-capacitance value curve.

10. The angle measuring device for a scanning device according to claim 9, characterized in that: The temperature drift compensation module determines the current value, voltage value or capacitance value corresponding to the current temperature according to the calibration information, and adjusts the adjustable power supply or adjustable capacitor according to the current value, voltage value or capacitance value.

11. The angle measuring device for a scanning device according to claim 4, 5 or 6, characterized in that: The temperature drift compensation module is configured to adjust the adjustable power supply or the adjustable capacitor according to the oscillation parameters at a preset temperature and a preset deflection angle.

12. The angle measuring device for a scanning device according to claim 1, characterized in that: The oscillation parameters include: an oscillation frequency, or an equivalent inductance value formed by the inductance unit and a conductive reference object disposed on the scanning device.

13. A method for measuring an angle of a scanning device, characterized in that: The method comprises: The driving circuit drives the LC oscillator to oscillate, and the temperature drift of the oscillation parameter is compensated by adjusting the oscillation parameter of the LC oscillator; the LC oscillator includes an inductor unit and a capacitor unit; An oscillation parameter of the LC oscillator is obtained, and a deflection angle of the scanning device is determined according to the oscillation parameter of the LC oscillator.

14. The angle measurement method for a scanning device according to claim 13, characterized in that: The driving circuit includes a cross-coupling circuit and a power supply.

15. The angle measurement method for a scanning device according to claim 14, characterized in that: The power supply includes an adjustable power supply; The compensating the temperature drift of the oscillation parameter by adjusting the oscillation parameter of the LC oscillator comprises: The oscillation parameters are adjusted by adjusting the size of the adjustable power supply.

16. The angle measurement method for a scanning device according to claim 13, characterized in that: The capacitor in the LC oscillator includes an adjustable capacitor; The compensating the temperature drift of the oscillation parameter by adjusting the oscillation parameter of the LC oscillator comprises: The oscillation parameter is adjusted by adjusting the value of the adjustable capacitor.

17. The angle measurement method for a scanning device according to claim 13, characterized in that: The capacitor in the LC oscillator includes a MOS variable capacitor; The compensating the temperature drift of the oscillation parameter by adjusting the oscillation parameter of the LC oscillator comprises: A bias voltage value adapted to compensate for the temperature drift of the oscillation parameter is provided to the MOS variable capacitor.

18. The angle measurement method for a scanning device according to claim 15 or 16, characterized in that: The compensating the temperature drift of the oscillation parameter by adjusting the oscillation parameter of the LC oscillator comprises: The adjustable power supply or the adjustable capacitor is adjusted according to the current temperature and calibration information.

19. The angle measurement method for a scanning device according to claim 18, characterized in that: The calibration information includes any one or more of the following: a temperature-current value data table, a temperature-current value curve, a temperature-voltage value data table, a temperature-voltage value curve, a temperature-capacitance value data table, and a temperature-capacitance value curve.

20. The angle measurement method for a scanning device according to claim 19, characterized in that: The adjusting the adjustable power supply or the adjustable capacitor according to the current temperature and the calibration information includes: Determine the current value, voltage value or capacitance value corresponding to the current temperature according to the calibration information; The adjustable power supply or the adjustable capacitor is adjusted according to the current value or the voltage value or the capacitance value.

21. The angle measurement method for a scanning device according to claim 15 or 16, characterized in that: The compensating the temperature drift of the oscillation parameter by adjusting the oscillation parameter of the LC oscillator comprises: The adjustable power supply or the adjustable capacitor is adjusted according to the inductance value of the inductor unit at a preset temperature and a deflection angle or the oscillation parameter at a preset temperature and a preset deflection angle.

22. The angle measurement method for a scanning device according to claim 13, characterized in that: The oscillation parameters include: an oscillation frequency, or an equivalent inductance value formed by the inductance unit and a conductive reference object disposed on the scanning device.

23. A laser radar, characterized in that: The laser radar comprises a scanning device, and an angle measuring device for the scanning device as claimed in any one of claims 1 to 12; The scanning device is provided with a conductive reference object; The inductance unit in the angle measuring device is installed toward the conductive reference object.

24. The laser radar according to claim 23, characterized in that: The scanning device includes a galvanometer or a rotating mirror.

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