WO2020142958A1

WO2020142958A1 - Motor control method, range sensor, and movable platform

Info

Publication number: WO2020142958A1
Application number: PCT/CN2019/071046
Authority: WO
Inventors: 陈鸿滨
Original assignee: 深圳市大疆创新科技有限公司
Priority date: 2019-01-09
Filing date: 2019-01-09
Publication date: 2020-07-16
Also published as: CN112106291A

Abstract

A motor control method, a range sensor, and a movable platform. The method (100) comprises: acquiring a current temperature of a bearing or a motor, wherein the bearing and the motor are directly or indirectly connected, and heat can be conducted therebetween (S110); determining an energization mode of the motor according to the current temperature, the energization mode comprising a heating mode and a rotating operation mode (S120); and controlling the motor such that a corresponding current is supplied thereto according to the energization mode, wherein in the heating mode, the motor is controlled such that a first pre-determined current is supplied thereto to generate heat and heat the bearing, and in the rotating operation mode, the motor is controlled such that a second pre-determined current is supplied thereto, such that the motor rotates at a first pre-determined speed to drive a function component to move (S130). The motor control method, the range sensor, and the movable platform reduce the viscosity of a lubricant by pre-heating a motor bearing at a low ambient temperature, thereby effectively reducing a motor current during start-up, and improving motor speed stability in a steady state.

Description

Motor control method, distance sensor and mobile platform

Technical field

The invention relates to the technical field of electric motors, in particular to the control of electric motors.

Background technique

As a widely used driving device, the motor often needs to work in different environments and applications. When the motor is used to drive the optical element, in order to ensure that the characteristics of the optical element are not affected, it is necessary to maintain the cleanliness of the surface of the optical element, and the bearing of the motor is covered with lubricating grease, which is easily volatilized and adheres to the surface of the optical element , You need to choose a less volatile lubricating grease. However, the viscosity of the grease with less hair becomes larger under low temperature environment, which causes the resistance of the motor to become larger. The starting current of the motor in different temperature environments is different. Under low temperature environment, the bearing friction of the motor will increase, resulting in The initial operation of the motor is not smooth or difficult to start, and it does not run smoothly even after starting.

Summary of the invention

Embodiments of the present invention provide an optical sensor, a power component, a distance sensor, and a mobile platform to solve the problem that the initial operation of the motor is not smooth or difficult to start in a low-temperature environment, and the operation is not stable even after starting.

In a first aspect, an embodiment of the present invention provides a motor control method, including:

Obtain the current temperature of the bearing or the motor, wherein the bearing and the motor are directly or indirectly connected, and the motor and the bearing can conduct heat with each other;

According to the current temperature, determine a power-on mode of the motor; wherein, the power-on mode includes a heating mode and a rotary working mode;

According to the energization mode, corresponding current is passed, wherein in the heating mode, the motor is controlled to pass a first preset current to generate heat to heat the bearing; in the rotary working mode, then The motor is controlled to pass a second preset current and rotate at a first preset speed to drive the functional component to move.

In a second aspect, an embodiment of the present invention provides a distance sensor, including:

Functional components, able to move;

A motor for driving the functional component;

The bearing is directly or indirectly connected to the motor, and the motor and the bearing can conduct heat with each other;

A controller, electrically connected to the motor, for controlling the working state of the motor,

Wherein, the controller can control the power-on mode of the motor, and the power-on mode includes a heating mode and a rotary working mode;

In the heating mode, the motor is fed with a first preset current to generate heat to heat the bearing;

In the rotary working mode, the motor is fed with a second preset current and rotates at a first preset speed to drive the functional component to move.

In a third aspect, an embodiment of the present invention provides a movable platform, which is characterized by including:

Platform ontology; and

The distance sensor according to the second aspect is installed on the platform body and is used for sensing the distance of obstacles around the platform body.

According to a fourth aspect, an embodiment of the present invention provides an optical sensor, including:

Optical components for reflecting or transmitting optical signals;

The hollow motor is used to accommodate the optical element and drive the optical element to rotate;

A bearing, directly or indirectly connected to the hollow motor, is used to restrict the rotor of the hollow motor from rotating with a fixed rotating shaft;

Wherein, the hollow motor and the bearing can conduct heat with each other, and before starting the hollow motor, a preset voltage can be applied to the hollow motor to preheat the bearing.

According to a fifth aspect, an embodiment of the present invention provides a power component, including:

The rotor assembly rotating around the rotating shaft includes an inner wall surrounding the rotating shaft, and the inner wall is formed with a hollow portion capable of accommodating optical elements;

A stator assembly, used to drive the rotor assembly to rotate around the rotating shaft;

A bearing assembly, connected to the rotor assembly, is used to restrict the rotation of the rotor assembly around a fixed rotating shaft;

Wherein, the stator assembly or/and the rotor assembly and the bearing can conduct heat with each other, and before starting the power component, a preset voltage can be applied to the hollow motor to preheat the bearing assembly .

The motor control method, distance sensor, mobile platform, optical sensor and power components of the embodiments of the present invention reduce the viscosity of grease by preheating the motor bearings when the ambient temperature is low, which effectively reduces the motor current and Improves the speed stability of the steady-state motor.

BRIEF DESCRIPTION

In order to more clearly explain the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, without paying any creative work, other drawings can be obtained based on these drawings.

FIG. 1 is a motor control method according to an embodiment of the present invention;

2 is an example of a heating mode of an embodiment of the present invention;

3 is an example of the initial state of the housing of the motor of the embodiment of the present invention;

4 is an example of the initial state of the winding of the motor of the embodiment of the present invention;

5 is an example of the temperature of the housing of the motor after 4 minutes of the heating mode of the embodiment of the present invention;

6 is an example of the temperature of the winding of the motor after 4 minutes of the heating mode of the embodiment of the present invention;

7 is a schematic structural block diagram of a distance measuring device according to an embodiment of the present invention;

8 is a schematic diagram of an embodiment of the distance measuring device of the present invention using a coaxial optical path.

detailed description

The technical solutions in the embodiments of the present invention will be described clearly and completely in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without making creative efforts fall within the protection scope of the present invention.

The bearing grease of the motor can provide full protection to the bearing and extend the bearing life. Different types of lubricating greases have different operating temperature ranges. In the low temperature section, the viscosity of the bearing lubricating grease becomes larger, which causes the resistance of the motor to become larger. Directly using a large torque to drag the motor to rotate, resulting in a large starting current of the motor, the initial operation of the motor is not smooth, and the stability of the steady state speed is poor. When the motor is used to drive functional parts (such as optical components), not only need to select low volatility grease, but also because the functional parts (such as optical components) are used as loads, the load is small and the stability of the motor operation Claim.

Based on the above considerations, in the first aspect, an embodiment of the present invention provides a motor control method. Referring to FIG. 1, FIG. 1 shows a motor control method according to an embodiment of the present invention. The method 100 includes:

In step S110, the current temperature of the bearing or the motor is obtained, wherein the bearing and the motor are directly or indirectly connected, and the motor and the bearing can conduct heat with each other;

In step S120, the power-on mode of the motor is determined according to the current temperature; wherein, the power-on mode includes a heating mode and a rotary working mode;

In step S130, according to the energization mode, a corresponding current is passed, wherein, in the heating mode, the motor is controlled to pass a first preset current to generate heat to heat the bearing; In the rotary working mode, the motor is controlled to pass a second preset current and rotate at a first preset speed to drive the functional component to move.

Among them, the temperature of the motor or bearing can reflect the lubricating degree of the lubricating grease at the current temperature. When the temperature is low, it means that the lubricating degree of the lubricating grease is low, and the friction of the bearing is large. The motor can be controlled to enter the heating mode and pass into the motor After the voltage overcurrent causes the motor winding to heat up, the heat is transferred to the bearing through thermal conduction to improve the lubricity of the grease, to reduce the starting current and ensure the temperature operation of the motor; when the temperature is higher, the friction of the motor's bearing The force is reduced, and there is no need to increase the temperature of the lubricating grease. The motor is easy to start and reaches a steady state of operation. The motor can be controlled to enter the rotary working mode to directly start normal operation.

Optionally, the magnitude of the first preset current is different from the magnitude of the second preset current.

Optionally, the first preset current is greater than the second preset current.

Optionally, the mode of inputting the first preset current to the three-phase winding of the motor is different from the mode of inputting the second preset current to the three-phase winding of the motor.

Since the heating mode is to generate heat conduction to the bearing, it is not enough to drive the rotor of the motor to rotate or rotate at the rotation speed during the rotary operation, then the first preset current in the heating mode is smaller than the second preset current in the rotary operation mode.

Optionally, in the heating mode, the three-phase windings of the motor are respectively supplied with the first preset current for substantially the same time.

Optionally, in the heating mode, the three-phase winding of the motor turns the first preset current in turn.

Optionally, in the heating mode, at least two of the three-phase windings of the motor are simultaneously fed with the first preset current.

It should be noted that in the above heating mode, passing the first preset current into the three-phase winding can make the motor winding heat evenly; similarly, the preset voltage can also be passed to make the motor winding heat evenly. For example, use The SVPWM controls the preset voltage and increases the temperature of the lubricating grease and improves the degree of lubrication under the premise of ensuring that the motor is not damaged.

In one embodiment, the preheating current of the same time is passed to any two-phase wheels of the A, B, and C three-phase coils of the motor, for example, the preheating current of 0.5A is first passed to the AB phase coil; After time t1, a preheating current of 0.5A is passed to the BC phase coil; after a time t1, a preheating current of 0.5A is passed to the CA phase coil; after time t1, the AB phase coil is passed again A preheating current of 0.5A; where the preheating current of the three-phase coils AB, BC, and CA all passing through time t1 is taken as a preheating cycle; and so on, after a preset period, when the coil temperature reaches a When the coil temperature is predetermined, the preheating of the coil is stopped.

In one embodiment, see FIG. 2, which shows an example of the heating mode in the embodiment of the present invention. As shown in Fig. 2, the preheating voltage is circulated through the three-phase coils A, B, and C of the motor, and the preheating voltage is controlled by the SVPWM (Space Vector Pulse Width Modulation, Space Vector Pulse Width Modulation) algorithm, for example The pulse-width modulated wave generated by the specific switching mode composed of the six power switching elements of the three-phase power inverter makes the output current waveform as close to the ideal sinusoidal waveform as possible, and the motor obtains the ideal circular flux linkage trajectory. Specifically, the three-phase phase voltages output by the inverter are UA, UB, and UC, which are respectively applied to a plane coordinate system with a spatial difference of 120 degrees, and the three voltage space vectors are defined as UA(t), UB( t), UC(t), their directions are always on their respective axes, and the size changes with time according to the sine law, and the time phase differs from each other by 120 degrees. Then the combined space vector U(t) of the three-phase voltage space vector is a rotating space vector, its amplitude is unchanged, it is the peak of the phase voltage, and it rotates in a counterclockwise direction at a constant frequency at an angular frequency of ω=2πf. The average value within a switching cycle is equal to the given voltage vector. Using the SVPWM algorithm to control the preheat voltage, the harmonic component of the current waveform in the coil of the motor is small, so that the torque ripple of the motor is reduced, the rotating magnetic field is closer to a circle, and it is easier to realize digitization.

Optionally, in the heating mode, the rotor of the motor is fixed.

Optionally, in the heating mode, the rotor of the motor rotates at a second preset speed.

Optionally, the second preset speed is less than the first preset speed.

Optionally, the second preset speed is less than 1/2 of the first preset speed; or, the second preset speed is less than 1/3 of the first preset speed; or, the The second preset speed is less than 1/4 of the first preset speed.

Among them, the first preset current in the heating mode may be small, which is only enough to generate heat to increase the bearing temperature and not enough to drive the rotor to rotate, and the rotor is still in a stationary state.

Optionally, the motion mode of the functional component includes at least one of the following: rotation, sliding, and swinging.

Optionally, the functional component includes at least one of the following: an optical element, an acoustic element, an electrical element, and a mechanical element.

The motor can drive the functional component to move, for example, to drive the optical element to move, and the moving optical element can reflect, refract, or diffract the light beam to different directions at different times.

Optionally, the motor is an inner rotor motor or an outer rotor motor.

Optionally, the motor is a hollow motor, and the functional component is located in the motor.

The hollow motor has a hollow accommodating space in the middle portion, so that functional components, such as optical elements, can be placed in the hollow accommodating space, and therefore, the volume of the driving device of the hollow motor can be effectively reduced.

Optionally, the functional component is located in the rotor of the motor and is fixedly connected to the rotor of the motor.

Optionally, the bearing is directly or indirectly connected to the stator of the motor; or/and, the bearing is directly or indirectly connected to the rotor of the motor.

Among them, the bearing is directly or indirectly connected to the stator or rotor of the motor, and heat can be obtained from other components of the motor through the connection to increase the temperature of the bearing, further improve the lubricity of the grease, and reduce the friction of the bearing Power to provide guarantee for the start and smooth operation of the motor.

In one embodiment, the stator and the bearing of the motor are installed on the bearing seat or the housing, the motor enters the heating mode, and the preset current or voltage is passed to the winding of the motor to heat the winding of the motor, and the generated heat is used over the winding It is transferred to the stator wound by the winding, and the stator transfers the heat to the bearing housing or the housing. The temperature of the bearing housing or the housing increases, thereby transferring the heat to the bearing. The bearing temperature rises finally makes the temperature of the grease on the bearing Increased, that is, the friction of the bearing is reduced, the motor is easier to start and can run smoothly after starting. As shown in Figures 3-6, Figures 3-6 show an example of the effect comparison of the heating mode of the embodiment of the present invention: Figure 3 shows an example of the initial state of the housing of the motor of the embodiment of the present invention; Figure 4 shows An example of the initial state of the winding of the motor of the embodiment of the present invention is shown; FIG. 5 shows an example of the temperature of the housing of the motor after 4 minutes of heating mode of the embodiment of the present invention; FIG. 6 shows a heating mode of 4 minutes of the embodiment of the present invention Example of the temperature of the winding of the motor afterwards; according to Figures 3 to 6, it can be seen that after the motor can be operated in a heating mode with a lower voltage (heating power of 9-10W) for 4 minutes, the temperature of the motor's housing stabilizes at around 42 degrees Celsius. The motor winding temperature is stable at around 90 degrees Celsius. When the heating mode time needs to be shortened, the heating power can be increased within the allowable temperature range of the winding, wherein the allowable temperature range of the winding is the temperature allowed under the premise of not being burned, which can be within 150 degrees Celsius, or Within 180 degrees Celsius, or within 220 degrees Celsius.

Optionally, when the temperature of the bearing is less than a preset temperature, the motor starts the heating mode.

Optionally, the preset temperature is less than or equal to 10 degrees Celsius; or, the preset temperature is less than or equal to 0 degrees Celsius; or, the preset temperature is less than or equal to minus 10 degrees Celsius; or, the preset temperature is less than or equal to minus 20 degrees Celsius; Degrees Celsius.

Optionally, the bearing is provided with lubricating grease, and the preset temperature is associated with the lubricating grease of the bearing.

Optionally, the damping of the lubricating grease decreases with increasing temperature; or/and, the volatility of the lubricating grease increases with increasing temperature.

Optionally, the bearing is arranged coaxially with the rotor of the motor.

Because the torque required to start the motor is related to the friction of the bearing of the motor, that is, the lubrication of the bearing grease, and the lubrication of the grease is related to the temperature of the grease, then the motor needs to be started The size of the torque is related to the temperature of the grease. Increasing the temperature of the grease can reduce the starting current of the motor. The lubricating grease covers the bearing, and its temperature is almost the same as the temperature of the bearing. Then the temperature of the motor itself and related parts of the motor can directly or indirectly reflect the temperature and friction of the bearing, and can be used to set the starting current. in accordance with. The temperature of the motor itself and related components of the motor can be directly measured by the temperature sensor, and the temperature of the motor itself can also be calculated indirectly according to the parameters of the motor.

Optionally, the temperature of the bearing is sensed by a temperature sensor or calculated by calculating electrical parameters of the motor.

Optionally, the parameters of the motor include at least one of the following: induced electromotive force and resistance.

The temperature of the bearing is increased by the above heating mode, and improving the lubricating degree of the lubricating grease can not only reduce the starting current, but also increase the success rate of the non-inductive control starting, and further improve the accuracy of the steady-state operating speed. In the sensorless control startup, since there is no sensor to directly obtain the position of the rotor through the sensor, the sensorless startup requires auto-rotation start. The motor can be rotated at a certain rate first. In the automatic process of the motor, it can be obtained by detecting the back EMF. Know the position of the rotor. The heating mode is the heating of the bearing of the motor, which reduces the starting current of the motor in a low temperature environment, reduces the difficulty of starting the motor, and ensures that the motor can start by rotation, thereby increasing the success rate of non-inductive control startup.

Depending on the application of the motor, it can be used to directly or indirectly drive the functional component to move and precisely control the movement mode. Therefore, according to different applications, the motor control method described in the first aspect and the motor adopting the method described in the first aspect may have the following applications:

Functional components, able to move;

A motor for driving the functional component;

Optionally, the first preset current is greater than the second preset current.

Optionally, the mode in which the first preset current is input to the three-phase winding of the motor is different from the mode in which the second preset current is input at the three-phase winding of the motor.

Optionally, in the heating mode, the rotor of the motor is fixed.

Optionally, the second preset speed is less than the first preset speed.

Optionally, the distance sensor includes at least one of the following: laser sensor, infrared sensor, ultrasonic sensor, monocular, and binocular.

Optionally, the motor is an inner rotor motor or an outer rotor motor.

Optionally, the bearing is arranged coaxially with the rotor of the motor.

Optionally, the controller is located outside the motor.

Optionally, the controller includes multiple controllable switches, such as MOS transistors. The heat dissipation of the controller is exported through the aluminum sheet through the thermal grease covered on the Mos tube, and the outside of the controller is completely wrapped with a heat shrinkable tube.

In a third aspect, an embodiment of the present invention provides a movable platform, including:

Platform ontology; and

The distance sensor according to the second aspect is installed on the platform body and used to sense the distance of obstacles around the platform body.

When the motor described in any of the above aspects includes a hollow motor, the motor may be used to drive the optical element to move.

Optical components for reflecting or transmitting optical signals;

Optionally, when preheating the bearing, a preheating voltage is input to the winding of the stator to uniformly heat the winding of the stator.

Optionally, the preheat voltage is controlled by the SVPWM algorithm.

Optionally, the bearing is covered with grease, and when the stator windings are heated uniformly so that the temperature of the stator increases, the temperature of the bearing seat and/or grease increases.

Optionally, when the temperature of the winding of the stator reaches a first threshold and/or the temperature of the bearing seat reaches a second threshold, the input of the preheating voltage to the winding of the stator is stopped.

Optionally, the higher the preheating voltage, the shorter the preheating time.

In one embodiment, the optical element in the light sensor is a prism or a lens, and may have an asymmetric shape. Wherein, the thickness of the prism may be different in the radial direction, so that when the prism rotates with the rotor of the hollow motor, the light beam incident from the side of the prism is refracted by the prism and exits, and when the rotor rotates to a different angle, the The light beam can be refracted to exit in different directions; the bearing is directly or indirectly connected to the hollow motor; real-time monitoring of the hollow motor can obtain the bearing temperature of the hollow motor, the temperature of the bearing seat, and the circuit board controlling the motor At least one of the temperatures, etc., when the at least one temperature is lower than the temperature threshold, it means that the ambient temperature of the light sensor is low, then before the hollow motor is started, the hollow motor can be passed according to SVPWM The preset voltage controlled by the algorithm preheats the bearings to make the stator winding of the hollow motor heat up evenly to ensure that the hollow motor is not damaged due to uneven heating. The heat generated by the winding passes through the winding, stator, bearing seat, bearing, The heat conduction path of the lubricating grease is transmitted from the winding to the lubricating grease, which increases the temperature and lubricating degree of the lubricating grease and reduces the starting current of the hollow motor; when the temperature of the bearing or the bearing seat of the hollow motor reaches a certain threshold, it stops The preset voltage is supplied to the hollow motor. It can be seen that preheating the bearing before the motor starts, reduces the viscosity of the grease on the bearing, effectively reduces the current of the motor during the startup process, improves the stability and accuracy of the steady-state motor speed, and thus ensures that the optical sensor is The motor does not cause an offset during the movement of the optical element, which improves the detection accuracy of the optical sensor.

According to a fifth aspect, a power component provided by an embodiment of the present invention includes:

Optionally, preheating the bearing assembly before starting the power component includes: inputting a preheating voltage to the winding of the stator assembly to uniformly heat the winding of the stator assembly.

Optionally, inputting a preheating voltage to the windings of the stator assembly to uniformly heat the windings of the stator assembly includes: using an SVPWM algorithm to control the preheating voltage.

Optionally, the bearing assembly is covered with lubricating grease. When the windings of the stator assembly are heated uniformly so that the temperature of the stator assembly increases, the temperature of the inner wall and/or the lubricating grease increases.

Optionally, when the temperature of the winding of the stator assembly reaches a first threshold and/or the temperature of the inner wall reaches a second threshold, the input of the preheating voltage to the winding of the stator assembly is stopped.

Optionally, the higher the preheating voltage, the shorter the preheating time.

Optionally, the power component may further include a weight block, which is disposed in the hollow portion of the power component and used to improve the dynamic balance when the optical element rotates together with the rotor assembly. There may be various configurations of the configuration block in the hollow part of the power component. For example, the projection of the optical element on the inner wall of the hollow portion on the inner wall of the hollow portion in a direction perpendicular to the rotation axis is discontinuous in position. Alternatively, the weights are continuous on the inner wall of the hollow portion in a position perpendicular to the projection of the optical element in a direction perpendicular to the rotation axis. Alternatively, the volume and weight of the counterweight at different positions along the rotation axis are different. Alternatively, a counterweight is provided between the optical element and the inner wall to fix the optical element to the inner wall and improve the dynamic balance when the optical element rotates together with the rotor assembly. Alternatively, the configuration block may not be provided in the hollow part of the power component, but may be provided at a position other than the hollow part of the power component, which is not limited herein.

Alternatively, instead of adding a configuration block to improve the dynamic balance when the optical element rotates with the rotor assembly in the power component, it is possible to improve the optical element and the optical element by removing some weight at the edge of the optical element The dynamic balance when the rotor assembly rotates together. For example, a notch is formed at the edge of the thicker portion of the optical element to improve the dynamic balance when the optical element rotates together with the rotor assembly. Of course, it is also possible to combine weights and remove some weight at the edge of the optical element to improve the dynamic balance when the optical element rotates together with the rotor assembly.

It should be noted that the optical elements in various aspects of the embodiments of the present invention may be replaced by other functional components such as acoustic elements, electrical elements, and mechanical elements.

The motor control method, distance sensor, light sensor, and power component provided by various embodiments of the present invention can be applied to a distance measuring device. The distance measuring device may be an electronic device such as a laser radar, a laser distance measuring device, or the like. In one embodiment, the distance measuring device is used to sense external environment information, for example, distance information, azimuth information, reflection intensity information, speed information, etc. of the environmental target. In one implementation, the distance measuring device can detect the distance between the detecting object and the distance measuring device by measuring the time of light propagation between the distance measuring device and the object, that is, Time-of-Flight (TOF). Alternatively, the distance measuring device may also detect the distance between the detected object and the distance measuring device through other techniques, such as a distance measuring method based on phase shift measurement, or a distance measuring method based on frequency shift measurement. There are no restrictions.

For ease of understanding, the following describes the working process of distance measurement in conjunction with the distance measurement device 700 shown in FIG. 7.

As shown in FIG. 7, the distance measuring device 700 may include a transmitting circuit 710, a receiving circuit 720, a sampling circuit 730 and an arithmetic circuit 740.

The transmitting circuit 710 may transmit a sequence of light pulses (for example, a sequence of laser pulses). The receiving circuit 720 can receive the optical pulse sequence reflected by the detected object, and photoelectrically convert the optical pulse sequence to obtain an electrical signal, which can be output to the sampling circuit 730 after processing the electrical signal. The sampling circuit 730 may sample the electrical signal to obtain the sampling result. The arithmetic circuit 740 may determine the distance between the distance measuring device 700 and the detected object based on the sampling result of the sampling circuit 730.

Optionally, the distance measuring device 700 may further include a control circuit 750, which can control other circuits, for example, can control the working time of each circuit and/or set parameters for each circuit.

It should be understood that although the distance measuring device shown in FIG. 7 includes a transmitting circuit, a receiving circuit, a sampling circuit, and an arithmetic circuit for emitting a beam of light for detection, the embodiments of the present application are not limited thereto, and the transmitting circuit , The number of any one of the receiving circuit, the sampling circuit, and the arithmetic circuit may also be at least two, for emitting at least two light beams in the same direction or respectively in different directions; wherein, the at least two light paths may be simultaneously The shot may be shot at different times. In one example, the light-emitting chips in the at least two emission circuits are packaged in the same module. For example, each emitting circuit includes a laser emitting chip, and the die in the laser emitting chips in the at least two emitting circuits are packaged together and housed in the same packaging space.

In some implementations, in addition to the circuit shown in FIG. 7, the distance measuring device 700 may further include a scanning module 760 for changing the propagation direction of at least one laser pulse sequence emitted by the transmitting circuit.

Among them, the module including the transmitting circuit 710, the receiving circuit 720, the sampling circuit 730, and the arithmetic circuit 740, or the module including the transmitting circuit 710, the receiving circuit 720, the sampling circuit 7730, the arithmetic circuit 740, and the control circuit 750 may be called a measurement A distance module, the distance measuring module may be independent of other modules, for example, the scanning module 760.

A coaxial optical path may be used in the distance measuring device, that is, the light beam emitted by the distance measuring device and the reflected light beam share at least part of the optical path in the distance measuring device. For example, after at least one laser pulse sequence emitted by the transmitting circuit is emitted by the scanning module to change the propagation direction, the laser pulse sequence reflected by the detection object passes through the scanning module and enters the receiving circuit. Alternatively, the distance measuring device may also adopt an off-axis optical path, that is, the light beam emitted from the distance measuring device and the reflected light beam are respectively transmitted along different optical paths in the distance measuring device. FIG. 8 shows a schematic diagram of an embodiment of the distance measuring device of the present invention using a coaxial optical path.

The distance measuring device 800 includes a distance measuring module 810. The distance measuring module 810 includes a transmitter 803 (which may include the above-mentioned transmitting circuit), a collimating element 804, and a detector 805 (which may include the above-mentioned receiving circuit, sampling circuit, and arithmetic circuit) and Optical path changing element 806. The ranging module 810 is used to emit a light beam, and receive back light, and convert the back light into an electrical signal. Among them, the transmitter 803 may be used to transmit a light pulse sequence. In one embodiment, the transmitter 803 may emit a sequence of laser pulses. Optionally, the laser beam emitted by the transmitter 803 is a narrow-bandwidth beam with a wavelength outside the visible light range. The collimating element 804 is disposed on the exit optical path of the emitter, and is used to collimate the light beam emitted from the emitter 803, and collimate the light beam emitted from the emitter 803 into parallel light to the scanning module. The collimating element is also used to converge at least a part of the return light reflected by the detection object. The collimating element 804 may be a collimating lens or other element capable of collimating the light beam.

In the embodiment shown in FIG. 8, the optical path changing element 806 is used to combine the transmitting optical path and the receiving optical path in the distance measuring device before the collimating element 804, so that the transmitting optical path and the receiving optical path can share the same collimating element, so that the optical path More compact. In some other implementation manners, the transmitter 803 and the detector 805 may respectively use respective collimating elements, and the optical path changing element 806 is disposed on the optical path behind the collimating element.

In the embodiment shown in FIG. 8, since the beam aperture of the light beam emitted by the transmitter 803 is small and the beam aperture of the return light received by the distance measuring device is large, the light path changing element can use a small area mirror to The transmitting optical path and the receiving optical path are combined. In some other implementations, the light path changing element may also use a reflector with a through hole, where the through hole is used to transmit the outgoing light of the emitter 803, and the reflector is used to reflect the return light to the detector 805. In this way, it is possible to reduce the blocking of the return light by the support of the small mirror in the case of using the small mirror.

In the embodiment shown in FIG. 8, the optical path changing element is offset from the optical axis of the collimating element 804. In some other implementations, the optical path changing element may also be located on the optical axis of the collimating element 804.

The distance measuring device 800 further includes a scanning module 802. The scanning module 802 is placed on the exit optical path of the distance measuring module 810. The scanning module 802 is used to change the transmission direction of the collimated light beam 819 emitted through the collimating element 804 and project it to the external environment, and project the return light to the collimating element 804 . The returned light is converged on the detector 805 via the collimating element 804.

In one embodiment, the scanning module 802 may include at least one optical element for changing the propagation path of the light beam, wherein the optical element may change the propagation path of the light beam by reflecting, refracting, diffracting, etc. the light beam. For example, the scanning module 802 includes a lens, a mirror, a prism, a galvanometer, a grating, a liquid crystal, an optical phased array (Optical Phased Array), or any combination of the above optical elements. In one example, at least part of the optical element is moving, for example, the at least part of the optical element is driven to move by a driving module, and the moving optical element can reflect, refract or diffract the light beam to different directions at different times. In some embodiments, multiple optical elements of the scanning module 802 may rotate or vibrate about a common axis 809, and each rotating or vibrating optical element is used to continuously change the direction of propagation of the incident light beam. In one embodiment, the multiple optical elements of the scanning module 802 may rotate at different rotation speeds, or vibrate at different speeds. In another embodiment, at least part of the optical elements of the scanning module 802 can rotate at substantially the same rotational speed. In some embodiments, the multiple optical elements of the scanning module may also rotate around different axes. In some embodiments, the multiple optical elements of the scanning module may also rotate in the same direction, or rotate in different directions; or vibrate in the same direction, or vibrate in different directions, which is not limited herein.

In one embodiment, the scanning module 802 includes a first optical element 814 and a drive 816 connected to the first optical element 814. The drive 816 is used to drive the first optical element 814 to rotate about a rotation axis 809 to change the first optical element 814 The direction of the collimated beam 818. The first optical element 814 projects the collimated light beam 819 in different directions. In one embodiment, the angle between the direction of the collimated light beam 819 changed by the first optical element and the rotation axis 809 changes as the first optical element 814 rotates. In one embodiment, the first optical element 814 includes a pair of opposed non-parallel surfaces through which the collimated light beam 819 passes. In one embodiment, the first optical element 814 includes a prism whose thickness varies along at least one radial direction. In one embodiment, the first optical element 814 includes a wedge angle prism, which aligns the straight beam 819 for refraction.

In one embodiment, the scanning module 802 further includes a second optical element 815. The second optical element 815 rotates about a rotation axis 809. The rotation speed of the second optical element 815 is different from the rotation speed of the first optical element 814. The second optical element 815 is used to change the direction of the light beam projected by the first optical element 814. In one embodiment, the second optical element 815 is connected to another driver 817, and the driver 817 drives the second optical element 815 to rotate. The first optical element 814 and the second optical element 815 may be driven by the same or different drivers, so that the rotation speed and/or rotation of the first optical element 814 and the second optical element 815 are different, thereby projecting the collimated light beam 819 to the outside space Different directions can scan a larger spatial range. In one embodiment, the controller 818 controls the

drivers

816 and 817 to drive the first optical element 814 and the second optical element 815, respectively. The rotation speeds of the first optical element 814 and the second optical element 815 can be determined according to the area and pattern expected to be scanned in practical applications.

Drives

816 and 817 may include motors or other drives.

In one embodiment, the second optical element 815 includes a pair of opposed non-parallel surfaces through which the light beam passes. In one embodiment, the second optical element 815 includes a prism whose thickness varies along at least one radial direction. In one embodiment, the second optical element 815 includes a wedge angle prism.

In one embodiment, the scanning module 802 further includes a third optical element (not shown) and a driver for driving the third optical element to move. Optionally, the third optical element includes a pair of opposed non-parallel surfaces through which the light beam passes. In one embodiment, the third optical element includes a prism whose thickness varies along at least one radial direction. In one embodiment, the third optical element includes a wedge angle prism. At least two of the first, second and third optical elements rotate at different rotational speeds and/or turns.

The rotation of each optical element in the scanning module 802 can project light into different directions, for example, the directions of the light 811 and 813, so as to scan the space around the distance measuring device 800. When the light 811 projected by the scanning module 802 hits the object 801 to be detected, a part of the light object 801 is reflected to the distance measuring device 800 in a direction opposite to the projected light 811. The returned light 812 reflected by the detected object 801 enters the collimating element 804 after passing through the scanning module 802.

The detector 805 and the transmitter 803 are placed on the same side of the collimating element 804. The detector 805 is used to convert at least part of the returned light passing through the collimating element 804 into an electrical signal.

In one embodiment, each optical element is coated with an antireflection coating. Optionally, the thickness of the antireflection film is equal to or close to the wavelength of the light beam emitted by the emitter 803, which can increase the intensity of the transmitted light beam.

In one embodiment, a filter layer is plated on the surface of an element on the beam propagation path in the distance measuring device, or a filter is provided on the beam propagation path to transmit at least the wavelength band of the beam emitted by the transmitter, Reflect other bands to reduce the noise caused by ambient light to the receiver.

In some embodiments, the transmitter 803 may include a laser diode through which laser pulses in the order of nanoseconds are emitted. Further, the laser pulse receiving time may be determined, for example, by detecting the rising edge time and/or the falling edge time of the electrical signal pulse. In this way, the distance measuring device 800 can use the pulse receiving time information and the pulse sending time information to calculate the TOF, thereby determining the distance between the detected object 801 and the distance measuring device 800.

The distance and orientation detected by the distance measuring device 800 can be used for remote sensing, obstacle avoidance, mapping, modeling, navigation, and the like. In an embodiment, the distance measuring device of the embodiment of the present invention may be applied to a mobile platform, and the distance measuring device may be installed on the platform body of the mobile platform. A mobile platform with a distance measuring device can measure the external environment, for example, measuring the distance between the mobile platform and obstacles for obstacle avoidance and other purposes, and performing two-dimensional or three-dimensional mapping on the external environment. In some embodiments, the mobile platform includes at least one of an unmanned aerial vehicle, a car, a remote control car, a robot, and a camera. When the distance measuring device is applied to an unmanned aerial vehicle, the platform body is the fuselage of the unmanned aerial vehicle. When the distance measuring device is applied to an automobile, the platform body is the body of the automobile. The car may be a self-driving car or a semi-automatic car, and no restriction is made here. When the distance measuring device is applied to a remote control car, the platform body is the body of the remote control car. When the distance measuring device is applied to a robot, the platform body is a robot. When the distance measuring device is applied to a camera, the platform body is the camera itself.

The present invention provides the above-mentioned motor control method, distance sensor, moving platform, light sensor, and power component, and reduces the viscosity of grease by preheating the motor bearing when the ambient temperature is low, which effectively reduces the motor current during startup And improve the speed stability of the steady state motor.

The technical terms used in the embodiments of the present invention are only used to describe specific embodiments and are not intended to limit the present invention. In this text, the singular forms "a", "the", and "said" are used to include plural forms unless the context clearly dictates otherwise. Further, the use of "including" and/or "comprising" in the specification refers to the existence of the described features, wholes, steps, operations, elements, and/or components, but does not exclude the presence or addition of one or more Other features, wholes, steps, operations, elements and/or components.

The corresponding structures, materials, actions, and equivalents of all devices or steps and functional elements (if any) in the appended claims are intended to include any structures, materials, or actions for performing the function in combination with other specifically required elements. The description of the present invention is given for the purpose of embodiments and description, but is not intended to be exhaustive or to limit the invention to the disclosed form. Various modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiments described in the present invention can better disclose the principle and practical application of the present invention, and enable those of ordinary skill in the art to understand the present invention.

The flowchart described in the present invention is only an embodiment, and various modifications and changes can be made to this illustration or the steps in the present invention without departing from the spirit of the present invention. For example, these steps can be performed in different orders, or certain steps can be added, deleted, or modified. Those of ordinary skill in the art may understand that all or part of the processes for implementing the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

A motor control method, characterized in that the method includes:

Obtain the current temperature of the bearing or the motor, wherein the bearing and the motor are directly or indirectly connected, and the motor and the bearing can conduct heat with each other;

According to the current temperature, determine a power-on mode of the motor; wherein, the power-on mode includes a heating mode and a rotary working mode;

According to the energization mode, corresponding current is passed, wherein in the heating mode, the motor is controlled to pass a first preset current to generate heat to heat the bearing; in the rotary working mode, then The motor is controlled to pass a second preset current and rotate at a first preset speed to drive the functional component to move.
The method according to claim 1, characterized in that the method comprises: a magnitude of the first preset current is different from a magnitude of the second preset current.
The method of claim 2, wherein the method comprises: a first preset current is greater than the second preset current.
The method according to claim 1, characterized in that the method comprises: a three-phase winding of the motor is input with a first preset current mode, and a three-phase winding of the motor is input with the second preset The current mode is different.
The method according to claim 1, wherein the method comprises: in the heating mode, the three-phase windings of the motor are respectively supplied with the first preset current for substantially equal time.
The method according to claim 1, wherein the method comprises: in the heating mode, the three-phase winding of the motor turns the first preset current in turn.
The method according to claim 1, characterized in that, in the heating mode, at least two of the three-phase windings of the motor are simultaneously fed with the first preset current.
The method of claim 1, wherein the method includes: in the heating mode, a rotor of the motor is fixed.
The method of claim 1, wherein the method includes: in the heating mode, the rotor of the motor rotates at a second preset speed.
The method of claim 9, wherein the method comprises: the second preset speed is less than the first preset speed.
The method of claim 10, wherein the method comprises: the second preset speed is less than 1/2 of the first preset speed; or, the second preset speed is less than the 1/3 of the first preset speed; or, the second preset speed is less than 1/4 of the first preset speed.
The method according to claim 1, wherein the movement mode of the functional component includes at least one of the following: rotation, sliding, and swinging.
The method of claim 1, wherein the functional component includes at least one of the following: an optical element, an acoustic element, an electrical element, and a mechanical element.
The method of claim 1, wherein the motor is an inner rotor motor or an outer rotor motor.
The method of claim 1, wherein the motor is a hollow motor, and the functional component is located in the motor.
The method according to claim 15, wherein the functional component is located in the rotor of the motor and is fixedly connected to the rotor of the motor.
The method of claim 1, wherein the bearing is directly or indirectly connected to the stator of the motor; or/and, the bearing is directly or indirectly connected to the rotor of the motor.
The method of claim 1, wherein the motor starts the heating mode when the temperature of the bearing is less than a preset temperature.
The method of claim 18, wherein the preset temperature is less than or equal to 10 degrees Celsius; or, the preset temperature is less than or equal to 0 degrees Celsius; or, the preset temperature is less than or equal to minus 10 degrees Celsius; or, The preset temperature is less than or equal to minus 20 degrees Celsius.
The method of claim 18, wherein the bearing is provided with lubricating grease, and the preset temperature is associated with the lubricating grease of the bearing.
The method of claim 20, wherein the damping of the lubricating grease decreases with increasing temperature; or/and, the volatility of the lubricating grease increases with increasing temperature.
The method of claim 1, wherein the bearing is disposed coaxially with the rotor of the motor.
A distance sensor, characterized in that it includes:

Functional components, able to move;

A motor for driving the functional component;

The bearing is directly or indirectly connected to the motor, and the motor and the bearing can conduct heat with each other;

A controller, electrically connected to the motor, for controlling the working state of the motor,

Wherein, the controller can control the power-on mode of the motor, and the power-on mode includes a heating mode and a rotary working mode;

In the heating mode, the motor is fed with a first preset current to generate heat to heat the bearing;

In the rotary working mode, the motor is fed with a second preset current and rotates at a first preset speed to drive the functional component to move.
The distance sensor according to claim 23, wherein the size of the first preset current is different from the size of the second preset current.
The distance sensor of claim 24, wherein the first preset current is greater than the second preset current.
The distance sensor according to claim 23, wherein the first preset current mode is input to the three-phase winding of the motor, and the second preset current mode is input to the three-phase winding of the motor different.
The distance sensor according to claim 23, characterized in that, in the heating mode, the three-phase windings of the motor are respectively supplied with the first preset current for substantially the same time.
The distance sensor according to claim 23, wherein in the heating mode, the three-phase winding of the motor turns the first preset current in turn.
The distance sensor according to claim 23, wherein in the heating mode, at least two of the three-phase windings of the motor are simultaneously fed with the first preset current.
The distance sensor according to claim 23, wherein the rotor of the motor is fixed in the heating mode.
The distance sensor of claim 23, wherein in the heating mode, the rotor of the motor rotates at a second preset speed.
The distance sensor of claim 24, wherein the second preset speed is less than the first preset speed.
The distance sensor according to claim 25, wherein the second preset speed is less than 1/2 of the first preset speed;

Or, the second preset speed is less than 1/3 of the first preset speed;

Alternatively, the second preset speed is less than 1/4 of the first preset speed.
The distance sensor according to claim 23, wherein the movement mode of the functional component includes at least one of the following: rotation, sliding, and swinging.
The distance sensor according to claim 23, wherein the functional component includes at least one of the following: an optical element, an acoustic element, an electrical element, and a mechanical element.
The distance sensor according to claim 23, wherein the distance sensor comprises at least one of the following: a laser sensor, an infrared sensor, an ultrasonic sensor, monocular, and binocular.
The distance sensor according to claim 23, wherein the motor is an inner rotor motor or an outer rotor motor.
The distance sensor according to claim 23, wherein the motor is a hollow motor, and the functional component is located in the motor.
The distance sensor according to claim 31, wherein the functional component is located in the rotor of the motor and is fixedly connected to the rotor of the motor.
The distance sensor according to claim 23, wherein the bearing is directly or indirectly connected to the stator of the motor;

Or/and, the bearing is directly or indirectly connected to the rotor of the motor.
The distance sensor of claim 23, wherein the motor starts the heating mode when the temperature of the bearing is less than a preset temperature.
The distance sensor according to claim 33, wherein the preset temperature is less than or equal to 10 degrees Celsius;

Or, the preset temperature is less than or equal to 0 degrees Celsius;

Or, the preset temperature is less than or equal to minus 10 degrees Celsius;

Alternatively, the preset temperature is less than or equal to minus 27 degrees Celsius.
The distance sensor according to claim 33, wherein the bearing is provided with lubricating grease, and the preset temperature is associated with the lubricating grease of the bearing.
The distance sensor according to claim 35, wherein the damping of the lubricating grease decreases as the temperature increases;

Or/and, the volatility of the lubricating grease increases as the temperature increases.
The distance sensor according to claim 23, wherein the bearing is disposed coaxially with the rotor of the motor.
The distance sensor of claim 23, wherein the controller is located outside the motor.
A movable platform is characterized by including:

Platform ontology; and

The distance sensor according to any one of claims 23 to 46, which is installed on the platform body and used for sensing the distance of an obstacle around the platform body.
An optical sensor, characterized in that it includes:

Optical components for reflecting or transmitting optical signals;

The hollow motor is used to accommodate the optical element and drive the optical element to rotate;

A bearing, directly or indirectly connected to the hollow motor, is used to restrict the rotor of the hollow motor from rotating with a fixed rotating shaft;

Wherein, the hollow motor and the bearing can conduct heat with each other, and before starting the hollow motor, a preset voltage can be applied to the hollow motor to preheat the bearing.
The optical sensor according to claim 48, wherein when preheating the bearing, a preheating voltage is input to the winding of the stator to uniformly heat the winding of the stator.
The optical sensor according to claim 49, wherein the preheat voltage is controlled by an SVPWM algorithm.
The optical sensor according to claim 49, wherein the bearing is covered with grease, and when the winding of the stator is heated uniformly so that the temperature of the stator rises, the bearing seat and/or the grease The temperature rises.
The optical sensor according to claim 49, wherein when the temperature of the winding of the stator reaches a first threshold and/or the temperature of the bearing seat reaches a second threshold, the input to the winding of the stator is stopped Describe the preheat voltage.
The optical sensor according to claim 49, wherein the higher the preheating voltage, the shorter the preheating time.
A power component, characterized in that the power component includes:

The rotor assembly rotating around the rotating shaft includes an inner wall surrounding the rotating shaft, and the inner wall is formed with a hollow portion capable of accommodating optical elements;

A stator assembly, used to drive the rotor assembly to rotate around the rotating shaft;

A bearing assembly, connected to the rotor assembly, is used to restrict the rotation of the rotor assembly around a fixed rotating shaft;

Wherein, the stator assembly or/and the rotor assembly and the bearing can conduct heat with each other, and before starting the power component, a preset voltage can be applied to the hollow motor to preheat the bearing assembly .
The power component according to claim 54, wherein preheating the bearing assembly before starting the power component includes: inputting a preheating voltage to the winding of the stator assembly to make the winding of the stator assembly uniform heating.
The power component according to claim 55, wherein inputting a preheating voltage to the windings of the stator assembly to uniformly heat the windings of the stator assembly includes controlling the preheating voltage using an SVPWM algorithm.
The power component according to claim 55, wherein the bearing assembly comprises: the bearing assembly is covered with lubricating grease, and when the winding of the stator assembly is heated uniformly so that the temperature of the stator assembly increases, The temperature of the inner wall and/or lubricating grease increases.
The power component according to claim 55, wherein the power component further comprises: when the temperature of the winding of the stator assembly reaches a first threshold and/or the temperature of the inner wall reaches a second threshold, stopping The winding of the stator assembly inputs the preheating voltage.
The power component of claim 55, wherein the power component further comprises: the higher the preheating voltage, the shorter the preheating time.