Door control system for vehicle lockage weighing
By combining the ground sensing coil, infrared detection circuit, and image acquisition module into the vehicle weighing access control system, the problem of low vehicle detection accuracy is solved, and fast and accurate vehicle passage and management are achieved.
Patent Information
- Application Number
- CN202422833737.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-20
- Publication Date
- 2025-09-26
- Estimated Expiration
- 2034-11-20
AI Technical Summary
The existing access control system for vehicle weighing at gates has low vehicle detection accuracy, especially for vehicles made of special materials or with special equipment, resulting in poor detection effect, which reduces the passage speed.
The system uses a combination of ground sensing coils and infrared detection circuits to improve the accuracy of vehicle detection through the complementary detection of multiple infrared sensors and ground sensing coils. It also combines the image acquisition module for vehicle identification and light detection to reduce interference and achieve precise weighing and access control.
It improves the accuracy of vehicle detection, reduces vehicle waiting time, avoids congestion, and enhances the safety and effectiveness of vehicle management.
Smart Images
Figure CN223390136U_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the technical field of vehicle management, and in particular to an access control system for vehicle weighing. Background Art
[0002] The access control system for vehicle weighing at the gate includes a vehicle detection module, a weighing module and an access control module. The vehicle detection module is used to detect vehicle signals at the gate, the weighing module is used to weigh the vehicle, and the access control module is used to control the opening or closing of the gate.
[0003] Installing a vehicle weighing and gate access control system at ports, toll booths, factory entrances, or logistics park entrances can speed vehicle passage and reduce waiting time. By automatically identifying vehicle information and weighing results, the system can quickly determine whether the vehicle meets the requirements for passage and automatically open the gate to allow the vehicle to pass quickly.
[0004] Existing vehicle detection modules usually use ground sensing coils to detect vehicles by sensing the magnetic field changes caused by the metal parts of the vehicle. Vehicles made of special materials or equipped with special equipment may interfere with the detection of the ground sensing coils, making it impossible to detect the vehicle and reducing the vehicle's speed. Utility Model Content
[0005] The disclosed embodiments provide an access control system for vehicle weighing to solve the problem of low vehicle detection accuracy of existing access control systems.
[0006] The embodiment of the present disclosure provides an access control system for vehicle weighing through a gate, including a vehicle detection module, a weighing module, and an access control module, all of which are connected to a first controller. The vehicle detection module includes a ground sensor coil, an infrared detection circuit, and an OR gate circuit. The infrared detection circuit includes multiple infrared sensors, multiple infrared detection branches, a sampling resistor, and a comparison circuit.
[0007] The first ends of the plurality of infrared detection branches are respectively connected to the output ends of the plurality of infrared sensors, the second ends of the plurality of infrared detection branches are all connected to the first end of the sampling resistor, the second end of the sampling resistor is grounded, the first end of the sampling resistor is connected to the first input end of the comparison circuit, the second input end of the comparison circuit is connected to the reference voltage, and the output end of the comparison circuit is connected to the first input end of the OR gate circuit.
[0008] The output end of the ground sensing coil is connected to the second input end of the OR gate circuit, and the output end of the OR gate circuit is the output end of the vehicle detection module.
[0009] In an exemplary embodiment of the present disclosure, the infrared detection branch includes a diode and a current-limiting resistor, the anode of the diode is the first end of the infrared detection circuit, the cathode of the diode is connected to the first end of the current-limiting resistor, and the second end of the current-limiting resistor is the second end of the infrared detection branch.
[0010] In an exemplary embodiment of the present disclosure, the vehicle access control system for weighing at a gate further includes:
[0011] A first image acquisition module is used to acquire vehicle images when the vehicle is weighed;
[0012] The first controller is configured to perform vehicle recognition based on the vehicle image.
[0013] In an exemplary embodiment of the present disclosure, the vehicle access control system for weighing at a gate further includes:
[0014] A second image acquisition module, arranged in front of the vehicle detection module according to the vehicle's traveling direction;
[0015] The first controller is configured to: identify vehicle flow based on the image captured by the second image acquisition module, and control the weighing module to enter a dormant state when the vehicle flow is less than a first set threshold.
[0016] In an exemplary embodiment of the present disclosure, the vehicle access control system for weighing at a gate further includes:
[0017] Light detection module, used to detect the light intensity entering the infrared sensor;
[0018] a light shield, arranged on the outside of the infrared sensor;
[0019] A first driving mechanism, configured to drive the light shield to rotate;
[0020] The first controller is configured to control the first driving mechanism to drive the light shield to rotate by a set angle when the output voltage of the light detection module is greater than a second set threshold.
[0021] In an exemplary embodiment of the present disclosure, the weighing module includes a pressure sensitive element R7, a digital potentiometer U2, a resistor R4, a resistor R5 and a subtraction circuit.
[0022] The pressure-sensitive element R7 is used to detect the weight of the vehicle. The pressure-sensitive element R7, the digital potentiometer U2, the resistor R4, and the resistor R5 form a bridge circuit. The control end of the digital potentiometer U2 is connected to the first controller.
[0023] The two output ends of the bridge circuit are respectively connected to the two input ends of the subtraction circuit, and the output end of the subtraction circuit is the output end of the weighing module.
[0024] In an exemplary embodiment of the present disclosure, the access control module 13 includes a second controller, a second driving mechanism, a gate rod and a radar detection module.
[0025] The second controller is connected to the first controller, the second driving mechanism is used to drive the gate rod to move, and the control end of the second driving mechanism is connected to the second controller;
[0026] The radar detection module is used to locate the vehicle position, and the output end of the radar detection module is connected to the second controller.
[0027] The working principle and beneficial effects of the vehicle weighing access control system provided by the embodiment of the present disclosure are as follows:
[0028] In the disclosed embodiment, the vehicle detection module adopts a combination of a ground sensing coil and an infrared detection circuit. The two usage modes complement each other and can improve the accuracy of vehicle detection.
[0029] Multiple infrared sensors are provided, forming multiple detection points at the gate, enabling detection of multiple vehicle positions. The output ends of the infrared sensors are connected to the first end of the infrared detection branch. When an infrared sensor detects a vehicle, the infrared sensor outputs a first-level signal, and current flows through the infrared detection branch. Otherwise, if an infrared sensor does not detect a vehicle, the infrared sensor outputs a second-level signal, and no current flows through the infrared detection branch. The second ends of the multiple infrared detection branches are connected to a sampling resistor. The greater the number of infrared sensors outputting the first-level signal, the greater the current flowing into the sampling resistor. Considering the varying sizes of vehicles, when a smaller vehicle approaches the gate, some infrared sensors will detect the vehicle and output the first-level signal, while others will not detect the vehicle and output the second-level signal. When the number of infrared sensors outputting the first-level signal exceeds a set number, the current flowing into the sampling resistor exceeds the set current, the voltage across the sampling resistor exceeds the reference voltage, and the comparator circuit outputs a high-level signal, indicating that the infrared detection circuit has detected the passage of a vehicle. The output end of the infrared detection circuit is connected to the first input end of the OR gate circuit.
[0030] At the same time, when the ground sensor coil detects a vehicle, the output end of the ground sensor coil is a high-level signal, and the output end of the ground sensor coil is connected to the second input end of the OR gate circuit. Any one of the infrared detection circuit and the ground sensor coil outputs a high-level signal, which will cause the OR gate circuit to output a high-level signal. When the first controller receives the high-level signal, it determines that a vehicle is approaching the gate.
[0031] The disclosed embodiment combines a ground sensor coil with an infrared detection circuit, thereby improving the accuracy of vehicle detection, promptly starting the weighing and access control processes, reducing vehicle waiting time, and avoiding vehicle congestion. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.
[0033] Figure 1 This is a principle block diagram of a vehicle access control system for weighing vehicles provided by an embodiment of the present disclosure;
[0034] Figure 2 is a circuit schematic diagram of a vehicle detection module provided by an embodiment of the present disclosure;
[0035] Figure 3 is a circuit schematic diagram of a weighing module provided in an embodiment of the present disclosure;
[0036] In the figure: 10 first controller, 11 vehicle detection module, 111 ground sensing coil, 112 infrared detection circuit, 12 weighing module, 13 access control module, 14 first image acquisition module, 15 second image acquisition module. DETAILED DESCRIPTION
[0037] To help those skilled in the art better understand this solution, the following will clearly describe the technical solutions in the embodiments of this solution in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of this solution, not all of it. Based on the embodiments of this solution, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of this solution.
[0038] Throughout the specification, claims, and accompanying figures of this solution, the term "including" and any variations thereof mean "including, but not limited to," and are intended to cover non-exclusive inclusions and are not limited to the examples listed herein. Furthermore, the terms "first" and "second," etc., are used to distinguish between different objects, not to describe a specific order.
[0039] The following describes the implementation of the present disclosure in detail with reference to the accompanying drawings:
[0040] Reference Figure 1-Figure 2The vehicle gate weighing access control system includes a vehicle detection module 11, a weighing module 12, and an access control module 13, all of which are connected to a first controller 10. The vehicle detection module 11 includes a ground sensor coil 111, an infrared detection circuit 112, and an OR gate circuit 113. The infrared detection circuit 112 includes multiple infrared sensors, multiple infrared detection branches, a sampling resistor, and a comparison circuit.
[0041] The first ends of the plurality of infrared detection branches are respectively connected to the output ends of the plurality of infrared sensors, the second ends of the plurality of infrared detection branches are all connected to the first end of the sampling resistor, the second end of the sampling resistor is grounded, the first end of the sampling resistor is connected to the first input end of the comparison circuit, the second input end of the comparison circuit is connected to the reference voltage, and the output end of the comparison circuit is connected to the first input end of the OR gate circuit 113.
[0042] The output end of the ground sensing coil 111 is connected to the second input end of the OR gate circuit 113 , and the output end of the OR gate circuit 113 is the output end of the vehicle detection module 11 .
[0043] In this embodiment, the vehicle detection module 11 adopts a combination of a ground sensing coil 111 and an infrared detection circuit 112 . The two methods complement each other and can improve the accuracy of vehicle detection.
[0044] The infrared sensor primarily consists of an infrared transmitter and an infrared receiver. The transmitter emits infrared light of a specific wavelength toward the vehicle detection area, while the receiver receives the infrared light reflected by objects. When no vehicle enters the detection area, the receiver receives less infrared light. When a vehicle enters the detection area, the vehicle's surface reflects the infrared light from the transmitter, increasing the intensity of the infrared light received by the receiver. If the signal strength received by the receiver exceeds the set value, it outputs a high-level signal, indicating that a vehicle has entered the detection area. If the signal strength is below the set value, it outputs a high-level signal, indicating that a vehicle is present.
[0045] In this embodiment, comparator U1 forms a comparator circuit. Multiple infrared sensors are provided (connected to the circuit via terminals P2-P5), forming multiple detection points at the gate, enabling detection of multiple vehicle positions. The output ends of the infrared sensors are connected to the first end of the infrared detection branch. When an infrared sensor detects a vehicle, it outputs a first-level signal (e.g., a high-level signal), and current flows through the infrared detection branch. Otherwise, if an infrared sensor does not detect a vehicle, it outputs a second-level signal, and no current flows through the infrared detection branch. The second ends of the multiple infrared detection branches are connected to a sampling resistor RC. The more infrared sensors outputting the first-level signal, the greater the current flowing into the sampling resistor RC. Given the varying sizes of vehicles, when a smaller vehicle approaches the gate, some infrared sensors will detect the vehicle and output the first-level signal, while others will not detect the vehicle and output the second-level signal (e.g., a low-level signal). When the number of infrared sensors outputting first-level signals is greater than a set number, the current flowing into the sampling resistor RC is greater than the set current, the voltage across the sampling resistor RC is greater than the reference voltage Vref, and the comparison circuit outputs a high-level signal, indicating that the infrared detection circuit 112 has detected a vehicle passing by. The output end of the infrared detection circuit 112 is connected to the first input end of the OR gate circuit U3.
[0046] At the same time, when the ground sensor coil 111 (connected to the circuit through terminal P1) detects a vehicle, the output end of the ground sensor coil 111 is a high-level signal, and the output end of the ground sensor coil 111 is connected to the second input end of the OR gate circuit U3. Therefore, any high-level signal output by the infrared detection circuit 112 and the ground sensor coil 111 will cause the OR gate circuit U3 to output a high-level signal. When the first controller 10 receives the high-level signal, it determines that a vehicle is approaching the gate.
[0047] From the above, it can be concluded that the embodiment of the present disclosure, by combining the ground sensor coil 111 and the infrared detection circuit 112, is conducive to improving the accuracy of vehicle detection, timely starting the weighing and access control process, reducing the waiting time of the vehicle, and avoiding vehicle congestion.
[0048] In an exemplary embodiment of the present disclosure, the infrared detection branch includes a diode and a current-limiting resistor, the anode of the diode is the first end of the infrared detection circuit 112, the cathode of the diode is connected to the first end of the current-limiting resistor, and the second end of the current-limiting resistor is the second end of the infrared detection branch.
[0049] In this embodiment, the infrared detection branch uses a diode and a current-limiting resistor. The diode acts as a unidirectional cutoff resistor. When the output of the infrared sensor is at a high level, the diode conducts, allowing current to flow through the infrared detection branch. Otherwise, when the output of the infrared sensor is at a low level, the diode is cut off, preventing current from flowing through the infrared detection branch. The current-limiting resistor acts as a current limiter to prevent excessive current from flowing through the diode.
[0050] Reference Figure 2 There are four infrared sensors, one for detecting the front, one for detecting the rear, and one for detecting the center of the vehicle. Considering the varying sizes of vehicles, a vehicle is detected if two of the four infrared sensors output high-level signals, meaning current flows through two of the four infrared detection branches. Therefore, the specific value of the reference voltage Vref can be determined based on the currents in the two branches and the sampling resistor RC.
[0051] From the above, it can be concluded that this embodiment implements the function of the infrared detection branch based on a diode and a current-limiting resistor. The number of infrared sensors that detect the vehicle is determined by detecting the current of multiple infrared detection branches. When the number of infrared sensors that detect the vehicle reaches a set value, it is determined that the vehicle is detected. Compared with vehicle detection by a single infrared sensor, the accuracy of vehicle detection can be improved.
[0052] In an exemplary embodiment of the present disclosure, the vehicle access control system for weighing at a gate further includes:
[0053] A first image acquisition module 14 is used to acquire vehicle images during vehicle weighing;
[0054] The first controller 10 is configured to perform vehicle recognition based on the vehicle image.
[0055] In this embodiment, the first image acquisition module 14 can be a camera. The first image acquisition module 14 is set at the position of the weighing module 12. When the vehicle is weighed, the vehicle image is captured by the first image acquisition module 14 and the vehicle image is uploaded to the first controller 10. The first controller 10 can process the vehicle image and identify the vehicle's appearance, license plate number, vehicle model and other features, thereby quickly and accurately determining the vehicle's identity information.
[0056] It should be noted that the method by which the first controller 10 processes the vehicle image belongs to the prior art and will not be described in detail here.
[0057] On the one hand, the identification of vehicle identity can improve the security of vehicle management. For example, the identified vehicle identity information can be compared with the vehicle information in the database to confirm whether the vehicle is an authorized vehicle. Only when the authorized vehicle approaches the gate will the access control module 13 be controlled to open the gate.
[0058] Furthermore, combining vehicle identity information with weighing data enables more comprehensive vehicle management. For example, the number of times different types of vehicles pass through the lock and their loads can be counted, providing data support for port operational decisions.
[0059] It can be concluded from the above that, in this embodiment, the first image acquisition module 14 is provided to capture vehicle images, and the vehicle identity information is obtained by identifying the vehicle images, thereby improving the safety and effectiveness of vehicle management.
[0060] In an exemplary embodiment of the present disclosure, the vehicle access control system for weighing at a gate further includes:
[0061] The second image acquisition module 15 is arranged in front of the vehicle detection module 11 according to the vehicle's traveling direction;
[0062] The first controller 10 is configured to: identify the vehicle flow based on the image captured by the second image acquisition module 15, and control the weighing module 12 to enter a dormant state when the vehicle flow is less than a first set threshold.
[0063] In this embodiment, a second image acquisition module 15 can be set in front of the vehicle detection module 11 to collect vehicle images in the oncoming direction and upload them to the first controller 10. The first controller 10 can obtain the traffic flow at the gate based on this. When the traffic flow is less than the first set threshold, it indicates that the traffic flow is very small. At this time, the weighing module 12 can be controlled to enter a sleep state to reduce the power consumption of the weighing module 12.
[0064] In an exemplary embodiment of the present disclosure, the vehicle access control system for weighing at a gate further includes:
[0065] Light detection module, used to detect the light intensity entering the infrared sensor;
[0066] A light shield is provided on the outside of the infrared sensor;
[0067] A first driving mechanism is used to drive the light shield to rotate;
[0068] The first controller 10 is configured to control the first driving mechanism to drive the light shield to rotate by a set angle when the output voltage of the light detection module is greater than a second set threshold.
[0069] In this embodiment, the light detection module can detect the light intensity entering the infrared sensor in real time. When the light intensity is greater than the second threshold, it indicates that the light intensity is too high. Excessive light intensity may generate stray light on the surface of surrounding objects, interfering with the normal reception of the infrared sensor, thereby affecting the accuracy of infrared detection. At this time, the first controller 10 can control the first drive mechanism to drive the light shield to rotate by a set angle. If the light intensity detected after rotation is less than the second threshold, the light shield rotation is stopped. Otherwise, the first drive mechanism continues to control the light shield to rotate by a set angle until the light intensity is less than the second threshold, thereby avoiding excessive light intensity that affects the accuracy of infrared detection. Among them, the first drive mechanism can use a motor, and the light shield rotation is achieved by controlling the rotation of the motor.
[0070] It can be concluded from the above that the arrangement of the light detection module, the light shield and the first driving mechanism in this embodiment can reduce the interference of light on the infrared sensor, thereby ensuring the normal operation of the external sensor.
[0071] In an exemplary embodiment of the present disclosure, the weighing module 12 includes a pressure sensitive element R7, a digital potentiometer U2, a resistor R4, a resistor R5 and a subtraction circuit.
[0072] The pressure-sensitive element R7 is used to detect the vehicle weight. The pressure-sensitive element R7, the digital potentiometer U2, the resistor R4, and the resistor R5 form a bridge circuit. The control end of the digital potentiometer U2 is connected to the first controller 10.
[0073] The two output ends of the bridge circuit are respectively connected to the two input ends of the subtraction circuit, and the output end of the subtraction circuit is the output end of the weighing module.
[0074] In this embodiment, pressure-sensitive element R7 can be a piezoresistor, a strain gauge, or the like. Resistors R6, R8, and R9, along with op amp U4, form a subtraction circuit. Pressure-sensitive element R7, digital potentiometer U2, resistors R4, and R5 form a bridge circuit. When weighing different vehicles, pressure-sensitive element R7 is subjected to different pressures, and the resistance of pressure-sensitive element R7 varies proportionally with the vehicle weight, causing the output voltage of the bridge circuit to change accordingly. The two output terminals of the bridge circuit are connected to the two input terminals of the subtraction circuit, respectively. The subtraction circuit outputs the voltage difference between the two output terminals of the bridge circuit and amplifies this voltage difference to generate a voltage signal proportional to the vehicle weight. Therefore, the vehicle weight can be determined by detecting the voltage signal at the output terminal of the subtraction circuit.
[0075] Considering that during long-term operation, pressure-sensitive element R7 may age due to environmental factors such as temperature and humidity, causing its resistance value to drift and resulting in inaccurate output signals from the weighing module, the weighing module can be zeroed by regularly adjusting the resistance of digital potentiometer U2. Specifically, when no vehicle is being weighed, the expected output of the weighing module is zero. If the actual output of the weighing module is not zero at this time, the resistance of digital potentiometer U2 can be adjusted to zero the output voltage of the bridge circuit, thereby achieving zero calibration of the weighing module.
[0076] It can be concluded from the above that, in this embodiment, the accuracy of the weighing module can be ensured by setting the digital potentiometer U2 to perform regular zero calibration on the weighing module.
[0077] In an exemplary embodiment of the present disclosure, the access control module 13 includes a second controller, a second driving mechanism, a gate rod and a radar detection module.
[0078] The second controller is connected to the first controller 10, the second driving mechanism is used to drive the gate rod to move, and the control end of the second driving mechanism is connected to the second controller;
[0079] The radar detection module is used to locate the position of the vehicle, and the output end of the radar detection module is connected to the second controller.
[0080] In this embodiment, the second controller can be a microcontroller such as a single-chip microcomputer, DSP, or ARM processor, and the second drive mechanism can be a motor. The second controller can receive control signals from the first controller 10 and drive the barrier pole to raise or lower, thereby enabling the first controller 10 to control the barrier pole.
[0081] As can be seen from the above, the communication between the second controller and the first controller 10 enables the coordinated operation of the weighing module 12 and the access control module 13. After weighing is completed, the first controller 10 can promptly transmit this information to the second controller to control the movement of the barrier gate, thereby improving the efficiency of the entire access control system. At the same time, the radar detection module can monitor the vehicle's position in the barrier area in real time and transmit it to the second controller. The second controller can then precisely control the timing of the barrier gate's movement based on the vehicle's position, ensuring safe passage and preventing vehicle damage accidents.
[0082] The above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present disclosure.
Claims
1. A vehicle access control system for weighing vehicles, comprising a vehicle detection module, a weighing module and an access control module, all connected to a first controller, characterized in that: The vehicle detection module includes a ground sensing coil, an infrared detection circuit and an OR gate circuit. The infrared detection circuit includes multiple infrared sensors, multiple infrared detection branches, a sampling resistor and a comparison circuit. The first ends of the plurality of infrared detection branches are respectively connected to the output ends of the plurality of infrared sensors, the second ends of the plurality of infrared detection branches are all connected to the first end of the sampling resistor, the second end of the sampling resistor is grounded, the first end of the sampling resistor is connected to the first input end of the comparison circuit, the second input end of the comparison circuit is connected to the reference voltage, and the output end of the comparison circuit is connected to the first input end of the OR gate circuit. The output end of the ground sensing coil is connected to the second input end of the OR gate circuit, and the output end of the OR gate circuit is the output end of the vehicle detection module.
2. The vehicle weighing access control system according to claim 1, characterized in that: The infrared detection branch includes a diode and a current limiting resistor, the anode of the diode is the first end of the infrared detection circuit, the cathode of the diode is connected to the first end of the current limiting resistor, and the second end of the current limiting resistor is the second end of the infrared detection branch.
3. The vehicle weighing access control system according to claim 1, characterized in that: Also includes: A first image acquisition module is used to acquire vehicle images when the vehicle is weighed; The first controller is configured to perform vehicle recognition based on the vehicle image.
4. The vehicle weighing access control system according to claim 1, characterized in that: Also includes: A second image acquisition module, arranged in front of the vehicle detection module according to the vehicle's traveling direction; The first controller is configured to: identify vehicle flow based on the image captured by the second image acquisition module, and control the weighing module to enter a dormant state when the vehicle flow is less than a first set threshold.
5. The vehicle weighing access control system according to claim 1, characterized in that: Also includes: Light detection module, used to detect the light intensity entering the infrared sensor; a light shield, arranged on the outside of the infrared sensor; A first driving mechanism, configured to drive the light shield to rotate; The first controller is configured to control the first driving mechanism to drive the light shield to rotate by a set angle when the output voltage of the light detection module is greater than a second set threshold.
6. The vehicle weighing access control system according to claim 1, characterized in that: The weighing module includes a pressure-sensitive element R7, a digital potentiometer U2, a resistor R4, a resistor R5 and a subtraction circuit. The pressure-sensitive element R7 is used to detect the weight of the vehicle. The pressure-sensitive element R7, the digital potentiometer U2, the resistor R4, and the resistor R5 form a bridge circuit. The control end of the digital potentiometer U2 is connected to the first controller. The two output ends of the bridge circuit are respectively connected to the two input ends of the subtraction circuit, and the output end of the subtraction circuit is the output end of the weighing module.
7. The vehicle weighing access control system according to claim 1, characterized in that: The access control module includes a second controller, a second driving mechanism, a gate rod and a radar detection module. The second controller is connected to the first controller, the second driving mechanism is used to drive the gate rod to move, and the control end of the second driving mechanism is connected to the second controller; The radar detection module is used to locate the vehicle position, and the output end of the radar detection module is connected to the second controller.