CN109870735B - Millimeter wave/terahertz wave security inspection instrument and reflecting plate scanning driving device thereof - Google Patents

Abstract

The invention provides a millimeter wave/terahertz wave security inspection instrument and a reflecting plate scanning driving device thereof, wherein the reflecting plate scanning driving device comprises a reflecting plate, and at least one soft magnet is arranged at intervals on the peripheral edge of the reflecting plate; a support bar hinged to the reflection plate and adapted to support the reflection plate; and the electromagnetic actuators are in one-to-one correspondence with the positions of the at least one soft magnet, each electromagnetic actuator comprises at least one actuating unit, each actuating unit comprises at least two electromagnets, the at least two electromagnets are arranged at intervals in a plane perpendicular to the reflecting plate, and the attraction force on the soft magnet is changed by changing the current of windings of the at least two electromagnets so as to drive the reflecting plate to swing between the two electromagnets. The movement of the reflecting plate can be controlled by controlling the current of the windings of the two electromagnets, so that the millimeter wave/terahertz wave security inspection instrument adopting the reflecting plate scanning driving device can flexibly adjust the shape and the size of the scanning area.

Description

Millimeter wave/terahertz wave security inspection instrument and its reflector scanning drive device

Technical Field

The present disclosure relates to the technical field of security inspection, and in particular to a reflector scanning drive device, and a millimeter wave/terahertz wave security inspection instrument including the reflector scanning drive device.

Background technique

Human body security inspection technology based on passive millimeter wave/terahertz wave has unique advantages. It realizes imaging by detecting the millimeter wave/terahertz wave radiation of the target itself, without active radiation, and performs security inspection on the human body. It uses the penetrating ability of millimeter wave/terahertz wave to realize the detection of hidden dangerous objects.

Currently, the application of passive millimeter wave/terahertz security inspection instruments is growing rapidly due to their unanimous recognition of their absolute safety. Since the detectors used in this type of instrument are expensive, only a small number of detectors are generally used, supplemented by appropriate reflector scanning drive devices to form a scanning field of view that can cover a single or multiple human bodies.

However, since passive millimeter wave/terahertz security scanners are usually installed in places with high personnel mobility, it is possible to adjust the shape and size of the scanning area according to actual conditions. However, the current passive millimeter wave/terahertz security scanners cannot flexibly adjust the shape and size of the scanning area.

Summary of the invention

The purpose of the present disclosure is to provide a reflector scanning drive device, which enables a millimeter wave/terahertz wave security inspection device to flexibly adjust the shape and/or size of a scanning area.

The present disclosure also aims to provide a millimeter wave/terahertz wave security inspection device that can flexibly adjust the shape and/or size of the scanning area.

According to an embodiment of one aspect of the present disclosure, a reflector scanning drive device is provided, comprising:

A reflector plate, wherein at least one soft magnetic body is arranged at intervals on the circumferential outer edge of the reflector plate;

A support rod, the support rod is hinged to the reflector plate and is suitable for supporting the reflector plate;

At least one electromagnetic actuator, at least one of the electromagnetic actuators and at least one of the soft magnetic bodies have a one-to-one correspondence, each of the electromagnetic actuators includes at least one actuating unit, and the actuating unit includes at least two electromagnets, and at least two of the electromagnets are arranged at intervals from each other in a plane perpendicular to the reflecting plate, and the current of the windings of at least two of the electromagnets is changed to change the attraction force on the soft magnetic body, thereby driving the reflecting plate to swing between the at least two electromagnets.

In some embodiments, the two electromagnets in the actuating unit share a U-shaped core, which includes a base and a first core portion and a second core portion respectively located at two ends of the base, the first core portion and the winding wound on the first core portion form an electromagnet in the actuating unit, and the second core portion and the winding wound on the second core portion form another electromagnet in the actuating unit.

In some embodiments, there are multiple actuating units, and the multiple actuating units are spaced apart from each other in a plane perpendicular to the reflective plate.

In some embodiments, the electromagnets in the actuation unit of the electromagnetic actuator are all located on an imaginary circle with the center of the reflection plate as the center.

In some embodiments, the number of the electromagnetic actuators is four.

In some embodiments, the four electromagnetic actuators are distributed radially symmetrically in pairs, and the electromagnet of one of the two electromagnetic actuators that are distributed radially symmetrically is distributed radially symmetrically with the electromagnet of the other electromagnetic actuator.

In some embodiments, the four electromagnetic actuators are equally spaced along the circumference of the reflective plate.

In some embodiments, the currents passing through the windings of the two radially symmetrically distributed electromagnets are equal.

In some embodiments, the windings of the two radially symmetrically distributed electromagnets are connected in series.

In some embodiments, the number of the electromagnetic actuators is three.

In some embodiments, the three electromagnetic actuators are equally spaced along the circumference of the reflective plate.

In some embodiments, the support rod is hinged to the center of the reflective plate.

In some embodiments, the support rod is hinged to the reflective plate via a ball bearing.

According to an embodiment of another aspect of the present disclosure, a millimeter wave/terahertz wave security inspection instrument is provided, comprising a reflective plate and the reflective plate scanning drive device as described above.

According to the reflector scanning drive device and millimeter wave/terahertz wave security inspection instrument described in the above-mentioned various embodiments of the present disclosure, by changing the current of the windings on the two electromagnets, the position of the magnetic poles of the synthetic magnetic field of the two electromagnets is changed, and then the direction of the attraction of the electromagnets to the soft magnet is changed, so as to drive the reflector connected to the soft magnet to move. By controlling the magnitude and change frequency of the current of the windings on the two electromagnets, the movement of the reflector can be completely controlled, so that the millimeter wave/terahertz wave security inspection instrument using the reflector scanning drive device can flexibly adjust the shape and size of the scanning area, and can adapt to the arrangement array of various detectors. As long as the stiffness of the reflector is large enough and the inertia is small, even only one detector can achieve two-dimensional scanning imaging.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of a reflector scanning driving device according to an embodiment of the present disclosure;

FIG2 is a schematic side view of the reflector scanning drive device shown in FIG1 ;

FIG3 is a schematic structural diagram of an electromagnetic actuator of a reflector scanning drive device according to the present disclosure;

FIG4 is a schematic structural diagram of two radially symmetrically distributed electromagnetic actuators of the reflector scanning drive device shown in FIG1 ;

FIG5 is a schematic structural diagram of another embodiment of two radially symmetrically distributed electromagnetic actuators of the reflector scanning drive device according to the present disclosure;

FIG6 is a schematic structural diagram of a reflector scanning driving device according to another embodiment of the present disclosure;

FIG7 is a schematic side view of the reflector scanning drive device shown in FIG6 ;

FIG8 is a schematic structural diagram of the reflector scanning drive device shown in FIG6 when the reflector is deflected; and

FIG. 9 is a schematic structural diagram of a control system of a reflector scanning drive device according to the present disclosure.

Detailed ways

Although the present disclosure will be fully described with reference to the accompanying drawings containing preferred embodiments of the present disclosure, it should be understood before this description that a person of ordinary skill in the art can modify the disclosure described herein while obtaining the technical effects of the present disclosure. Therefore, it should be understood that the above description is a broad disclosure to a person of ordinary skill in the art, and its content is not intended to limit the exemplary embodiments described in the present disclosure.

In addition, in the detailed description below, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the disclosed embodiments. However, it is apparent that one or more embodiments may be implemented without these specific details. In other cases, known structures and devices are embodied in a schematic manner to simplify the accompanying drawings.

FIG1 and FIG2 schematically show a reflector scanning drive device according to an embodiment of the present disclosure, which is particularly suitable for controlling the movement of a reflector 1 of a millimeter wave/terahertz wave security inspection instrument. As shown in the figure, the reflector scanning drive device includes a support rod 3, a reflector 1 and an electromagnetic actuator 2, wherein the support rod 3 is hinged to the reflector 1 and is suitable for supporting the reflector 1; four soft magnetic bodies 5, such as soft iron, are arranged at intervals on the circumferential outer edge of the reflector 1; the number of electromagnetic actuators 2 is also four, and the positions of the four electromagnetic actuators 2A, 2B, 2C, and 2D correspond to each other. Each electromagnetic actuator 2 includes at least two electromagnets arranged at intervals from each other, and the at least two electromagnets are arranged at intervals from each other in a plane perpendicular to the reflector 1. By changing the current of the windings of the two electromagnets, the attraction to the soft magnetic body 5 is changed, thereby driving the reflector 1 to swing between the two electromagnets.

According to the reflector scanning drive device of the embodiment of the present disclosure, the current of the windings of the two electromagnets is changed, thereby changing the position of the magnetic poles of the synthetic magnetic field of the two electromagnets, and then changing the direction of the attraction of the electromagnets to the soft magnetic body 5. That is to say, the posture of the reflector 7 can be completely controlled by controlling the current of the windings on the two electromagnets, wherein the magnitude of the current determines the locking force on the reflector 1, the relative magnitude of the current of the windings of the two electromagnets determines the posture of the reflector 1, and the frequency of change of the current determines the scanning speed of the millimeter wave/terahertz wave security inspection device using the reflector scanning drive device. The movement of the reflector 1 is controlled by controlling the magnitude and frequency of change of the current of the windings on the two electromagnets, so that the millimeter wave/terahertz wave security inspection device using the reflector scanning drive device can flexibly control the shape and size of the scanning area, and can adapt to the arrangement array of multiple detectors, as long as the stiffness of the reflector 1 is large enough and the inertia is small, even one detector can achieve two-dimensional scanning imaging. In addition, the control of the current of the windings of the electromagnets can adopt the existing high-precision control technology, and the electromagnetic actuator is low in cost, small in size and weight.

As shown in FIG3 , in an exemplary embodiment, the two electromagnets in the electromagnetic actuator 2 are formed by an integral iron core, which is in a U-shaped structure and includes a base and a first iron core portion 2-A ₁ and a second iron core portion 2-B ₁ located at both ends of the base, respectively. The first iron core portion 2-A ₁ and the winding 2-A ₂ wound on the first iron core portion 2-A ₁ form an electromagnet in the actuation unit, and the second iron core portion 2-B ₁ and the winding 2-B ₂ wound on the second iron core portion 2-B ₁ form another electromagnet in the actuation unit. In this embodiment, the winding 2-A ₂ on the first iron core portion 2-A ₁ and the winding 2-B ₂ on the second iron core portion are exactly the same. The currents passing through the winding 2-A ₂ on the first iron core portion 2-A ₁ and the winding 2-B ₂ on the second iron core portion 2-B ₂ are I ₁ and I ₂ , respectively. When I ₁ =1 and I ₂ =0, the soft magnetic body 5 is attracted by magnetic force and faces the first electromagnet (i.e., the first core part 2-A ₁ ). As long as the current remains unchanged, the orientation of the soft magnetic body 5 will not change. Similarly, when I ₁ =0 and I ₂ =1, the soft magnetic body 5 faces the second electromagnet (i.e., the second core part 2-B ₁ ). Since the magnetic field is a vector, when I ₁ =sinθ and I ₂ =cosθ, the synthesized magnetic pole is located between the first electromagnet and the second electromagnet, so the soft magnetic body 5 faces the direction. Using this principle, using two currents I ₁ and I ₂ that satisfy the sine law, the soft magnetic body 5 can drive the reflector 1 to swing at a fixed angle and stop at a specified angular displacement. Thus, electromagnetic actuation is achieved.

As shown in Figures 1 and 4, in an exemplary embodiment, four electromagnetic actuators 2A, 2B, 2C, and 2D are evenly spaced along the circumference of the reflector 1, that is, the reflector 1 is push-pull driven by four electromagnetic actuators 2A, 2B, 2C, and 2D located in the directions of 0°, 90°, 180°, and 270°, wherein the electromagnetic actuators 2B and 2D in the two horizontal directions of 0° and 180° are complementary driven, and the electromagnetic actuators 2A and 2C in the two vertical directions of 90° and 270° are complementary driven.

It should be noted that those skilled in the art should understand that in some other embodiments of the present disclosure, the four electromagnetic actuators 2A, 2B, 2C, and 2D may also be arranged along the circumferential non-equally spaced portions of the reflector 1. For example, in one embodiment, the four electromagnetic actuators 2A, 2B, 2C, and 2D are radially symmetrically distributed in pairs. More specifically, the electromagnets in one of the two radially symmetrically distributed electromagnetic actuators are radially symmetrically distributed with the electromagnets in the other electromagnetic actuator. The straight line where the two radially symmetrically distributed electromagnetic actuators 2A and 2C are located may be at an angle of less than 90° with the straight line where the other two radially symmetrically distributed electromagnetic actuators 2B and 2D are located. Since the four electromagnetic actuators 2A, 2B, 2C, and 2D are arranged radially opposite to each other in pairs, the reflector 1 can be controlled to achieve movement and maintenance of any angular displacement (not exceeding the maximum angular displacement that the electromagnetic actuator can output) in the horizontal and vertical directions.

As shown in Fig. 4, in some exemplary embodiments, the windings on the electromagnets in the two electromagnetic actuators that are symmetrically distributed along the center radial direction of the reflector 1 are connected in series. That is, the winding 2A-A ₂ on the first core part 2A-A ₁ in the electromagnetic actuator 2A and the winding 2C-A ₂ on the second core part 2C-A ₁ in the electromagnetic actuator 2C are connected in series, and the winding 2A-B ₂ on the second core part 2A-B ₁ in the electromagnetic actuator 2A and the winding 2C-B ₂ on the second core part 2C-B ₁ in the electromagnetic actuator 2C are also connected in series. According to the principle described above, when I ₁ = 1 and I ₂ = 0, the electromagnet formed by the first core part 2A-A ₁ and the winding 2A-A ₂ thereon in the electromagnetic actuator 2A and the electromagnet formed by the first core part 2C-A ₁ and the winding 2C-A ₂ thereon in the electromagnetic actuator 2C simultaneously generate attractive forces to apply a rotational torque to the reflector 1, so that it stays and remains at the angular displacement shown by the solid line in the figure. By controlling the currents I ₁ and I ₂ , the reflector 1 can also be maintained at the angular displacement shown by the dotted line, or at any position between the angular displacement shown by the solid line and the angular displacement shown by the dotted line.

It should be noted that those skilled in the art should understand that in some other embodiments of the present disclosure, the windings on the radially symmetrically distributed electromagnets in the two electromagnetic actuators may not be connected in series, for example, the same current may be applied to them through different current sources.

As shown in FIG. 5 , in an exemplary embodiment, the number of actuating units in the electromagnetic actuator is two, and the two actuating units are spaced apart from each other in a plane perpendicular to the reflective plate 1 . Each actuating unit includes three electromagnets arranged at intervals from each other, that is, the actuating unit located on the upper left side of FIG. 5 includes three electromagnets, each of which is respectively formed by an iron core 2A-1-A ₁ , 2A-1-B ₁ , 2A-1-C ₁ and a winding 2A-1-A ₂ , 2A-1-B ₂ , 2A-1-C ₂ wound thereon; similarly, the actuating unit located on the upper right side of FIG. 5 also includes three electromagnets, each of which is respectively formed by an iron core 2A-2-A ₁ , 2A-2-B ₁ , 2A-2-C ₁ and a winding 2A-2-A ₂ , 2A-2-B 2, 2A-2-C ₂ wound thereon; the actuating unit located on the lower left side of FIG. 5 includes three electromagnets, each of which is respectively formed by an iron core 2C-2-A 1, 2C-2-B ₁ , 2C-2-C ₁ and a winding 2A-2-A 2, 2A-2-B ₂ , 2A-2-C 2 wound thereon ₁ and windings 2C-2-A ₂ , 2C-2-B ₂ , 2C-2-C ₂ wound thereon; the actuating unit located at the lower right side of FIG5 includes three electromagnets, each of which is respectively formed by an iron core 2C-1-A ₁ , 2C-1-B ₁ , 2C-1-C ₁ and windings 2C-1-A ₂ , 2C-1-B ₂ , 2C-1-C ₂ wound thereon. In addition, the six electromagnets located on the upper side and the six electromagnets located on the lower side are all located on an imaginary circle with the center of the reflector 1 as the center.

In this embodiment, the two electromagnetic actuators can be controlled by three currents, that is, winding 2A-1-A ₂ , winding 2C-2-A ₂ , winding 2C-1-A ₂ , and winding 2A-2-A ₂ are connected in series, and the current passing through them is _IA ; winding 2A-1-B ₂ , winding 2C-2-B ₂ , winding 2C-1-B ₂ , and winding 2A-2-B ₂ are connected in series, and the current passing through them is I _B ; winding 2A-1-C ₂ , winding 2C-2-C ₂ , winding 2C-1-C ₂ , and winding 2A-2-C ₂ are connected in series, and the current passing through them is I _C. By using two actuating units, each of which includes three electromagnets, a large-angle swing of the reflector can be achieved, so that the shape and area size of the scanning of the millimeter wave/terahertz wave security inspection device using the reflector scanning drive device can be adjusted within a large range. In addition, by using three control currents, it is easy to realize the operation of the soft magnetic body 5 across the electromagnet.

It should be noted that those skilled in the art should understand that in some other embodiments of the present disclosure, other numbers of electromagnetic actuators 2 may be used, such as 5, 6, etc. The number of actuating units in each electromagnetic actuator may also be 2 or 3, etc., and the number of electromagnets in each actuating unit may also be 4 or 5, etc. Generally speaking, the more and denser the electromagnets are, the smoother the operation of the reflector 1 is, and the easier it is to achieve large-angle swing.

As shown in Fig. 2, Fig. 4, Fig. 5 and Fig. 7, in an exemplary embodiment, the support rod 3 is connected to the center of the reflector 1 through the ball bearing 4. Here, the center of the reflector 1 refers to the geometric center and mass center of the reflector 1. The support rod 3 is used to support the reflector 1 and also serves as the axis when the reflector 1 swings in two dimensions. Since the entire weight of the reflector 1 is borne by the bearings and the support rods, the force required for swinging and positioning is not large. In addition, since the reflector 1 will not rotate continuously in a full circle, the wear of the ball bearing 4 will not be very large.

Figures 6 and 7 show a reflector scanning drive device according to another embodiment of the present disclosure. In this exemplary embodiment, the number of electromagnetic actuators 2 is 3, and the 3 electromagnetic actuators 2A', 2B', and 2C' are distributed at intervals of 120° along the circumference of the reflector 1. When one of the electromagnetic actuators is in motion, the other two electromagnetic actuators need to cooperate synchronously.

As shown in FIG6 , a mark point M is selected on the reflective surface of the reflector 1. At time zero (t=0), the point M is located on the line connecting the center of the reflective surface of the reflector 1 and the center of the electromagnetic actuator 2A', and at this time, the reflective surface of the reflector 1 is in a state where the vertical swing angle is the maximum value θ _V (single direction) and the horizontal swing angle is zero. The angular velocity of the mark point M rotating around the center of the reflective surface of the reflector 1 is ω _s .

As shown in Fig. 8, the maximum vertical swing angle of the reflective surface of the reflector 1 is _θH (single direction), and the maximum horizontal swing angle is _θV (single direction). In order to realize an elliptical scanning area that is "high in vertical direction and narrow in horizontal direction", _θH > _θV .

Assume that each electromagnetic actuator 2A', 2B', 2C' includes two electromagnets, the second core portion of the electromagnetic actuator 2B' is arranged adjacent to the first core portion of the electromagnetic actuator 2A', the first core portion of the electromagnetic actuator 2C' is arranged adjacent to the second core portion of the electromagnetic actuator 2B', the maximum current on the windings of the electromagnetic actuators 2A', 2B', 2C' is equal, and Indicates that The higher the value, the greater the driving force. I _A1 represents the current of the winding on the first core part of the electromagnetic actuator 2A', I _A2 represents the current of the winding on the second core part of the electromagnetic actuator 2A', I _B1 represents the current of the winding on the first core part of the electromagnetic actuator 2B', I _B2 represents the current of the winding on the second core part of the electromagnetic actuator 2B', I _C1 represents the current of the winding on the first core part of the electromagnetic actuator 2C', and I _C2 represents the current of the winding on the second core part of the electromagnetic actuator 2C'. The functional relationship between each current and time t is:

It should be noted that those skilled in the art should understand that in some other embodiments of the present disclosure, the three electromagnetic actuators 2A’, 2B’, and 2C’ may also be distributed at unequal intervals in the circumferential direction of the reflector 1.

As shown in FIG9 , the reflector scanning drive device also includes a control system for controlling the movement of the reflector 1. The user can set the scanning frame rate, scanning area shape (including shape and size), detector arrangement, maximum driving current, subdivision step number (the number of decomposition steps in each scanning cycle) and driving mode (four electromagnetic actuators or three electromagnetic actuators) through the interface 8. Then the calculation processing module 9 calculates the response running trajectory according to these commands, and calculates the output components of each electromagnetic actuator according to the current time, and then outputs them to the digital-to-analog converters 6A and 6B to convert them into voltages, and then converts them into the required output currents through the voltage-controlled current sources 7A, 7B, 7C, 7D; 7A’, 7B’, 7C’, 7D’, 7E’, 7F’. When four electromagnetic actuators are used, four digital-to-analog converters 6A and four voltage-controlled current sources 7A, 7B, 7C, and 7D are required. When three electromagnetic actuators are used, six digital-to-analog converters 6B and six voltage-controlled current sources 7A’, 7B’, 7C’, 7D’, 7E’, and 7F’ are required.

According to another aspect of the present disclosure, a millimeter wave/terahertz wave security inspection instrument is also provided, comprising an optical component, a detector array and the reflector scanning drive device as described above. The optical component is suitable for reflecting and converging the beams spontaneously radiated by the inspected object or reflected by the inspected object to the detector array, and comprises a reflector suitable for receiving and reflecting the beams from the inspected object. The detector array is suitable for receiving the beams reflected and converged by the optical component.

According to the reflector scanning drive device and millimeter wave/terahertz wave security inspection instrument described in the above-mentioned various embodiments of the present disclosure, by changing the current of the windings on the two electromagnets, the position of the magnetic poles of the synthetic magnetic field of the two electromagnets is changed, and then the direction of the attraction of the electromagnets to the soft magnet is changed, so as to drive the reflector connected to the soft magnet to move. By controlling the magnitude and change frequency of the current of the windings on the two electromagnets, the movement of the reflector 1 can be completely controlled, so that the millimeter wave/terahertz wave security inspection instrument using the reflector scanning drive device can flexibly adjust the shape and size of the scanning area, and can adapt to the arrangement array of various detectors. As long as the stiffness of the reflector 1 is large enough and the inertia is small, even one detector can achieve two-dimensional scanning imaging.

Those skilled in the art can understand that the embodiments described above are exemplary and can be improved by those skilled in the art. The structures described in various embodiments can be freely combined without causing conflicts in structure or principle.

After describing the preferred embodiments of the present disclosure in detail, those skilled in the art can clearly understand that various changes and modifications can be made without departing from the scope and spirit of the appended claims, and the present disclosure is not limited to the implementation methods of the exemplary embodiments listed in the specification.

Claims (14)

1. A reflector scanning drive device, comprising: A reflector plate, wherein a plurality of soft magnetic bodies are arranged at intervals on the circumferential outer edge of the reflector plate; A support rod, the support rod is hinged to the reflector plate and is suitable for supporting the reflector plate; A plurality of electromagnetic actuators, wherein the positions of the plurality of electromagnetic actuators and the plurality of soft magnetic bodies are in a one-to-one correspondence, each of the electromagnetic actuators comprises at least one actuating unit, and the actuating unit comprises at least two electromagnets, and at least two of the electromagnets are arranged at intervals from each other in a plane perpendicular to the reflecting plate, and the current of the windings of the at least two electromagnets is changed to change the attraction force on the soft magnetic body, thereby driving the reflecting plate to swing between the at least two electromagnets. 2. The reflector plate scanning drive device according to claim 1, wherein the two electromagnets in the actuating unit share a U-shaped iron core, the iron core comprising a base and a first iron core portion and a second iron core portion respectively located at two ends of the base, the first iron core portion and the winding wound on the first iron core portion form an electromagnet in the actuating unit, and the second iron core portion and the winding wound on the second iron core portion form another electromagnet in the actuating unit. 3 . The reflective plate scanning driving device according to claim 1 , wherein the number of the actuating units is plural, and the actuating units are spaced apart from each other in a plane perpendicular to the reflective plate. 4 . The reflector scanning drive device according to claim 1 , wherein the electromagnets in the actuating unit of the electromagnetic actuator are all located on an imaginary circle with the center of the reflector as the center. 5 . The reflection plate scanning driving device according to claim 1 , wherein the number of the electromagnetic actuators is four. 6. The reflector scanning drive device according to claim 5, wherein the four electromagnetic actuators are distributed radially symmetrically in pairs, and the electromagnet of one of the two electromagnetic actuators distributed radially symmetrically is distributed radially symmetrically with the electromagnet of the other electromagnetic actuator. 7 . The reflective plate scanning driving device according to claim 6 , wherein the four electromagnetic actuators are distributed at equal intervals along the circumference of the reflective plate. 8 . The reflector scanning driving device according to claim 6 , wherein currents passing through the windings of the two electromagnets which are radially symmetrically distributed are equal. 9 . The reflection plate scanning driving device according to claim 8 , wherein the windings of the two radially symmetrically distributed electromagnets are connected in series. 10 . The reflection plate scanning driving device according to claim 1 , wherein the number of the electromagnetic actuators is three. 11 . The reflective plate scanning driving device according to claim 10 , wherein the three electromagnetic actuators are distributed at equal intervals along the circumference of the reflective plate. 12. The reflective plate scanning drive device according to any one of claims 1 to 11, wherein the support rod is hinged to the center of the reflective plate. 13 . The reflective plate scanning drive device according to claim 12 , wherein the support rod is hinged to the reflective plate via a ball bearing. 14. A millimeter wave/terahertz wave security inspection instrument, comprising a reflector and a reflector scanning drive device according to any one of claims 1 to 13.