Speed closed loop non-programming electromagnetic track trolley

Abstract

This utility model discloses a non-programmable electromagnetic tracking vehicle with speed closed-loop control, comprising an electromagnetic tracking vehicle and a control device. The control device includes an LC parallel resonant circuit, a multi-stage amplifier circuit, a PID operational amplifier circuit, a comparator circuit, a motor drive circuit, a frequency-to-voltage conversion circuit, and a triangular wave generation circuit. The output terminal of the LC parallel resonant circuit is connected to the input terminal of the multi-stage amplifier circuit; the output terminal of the multi-stage amplifier circuit is connected to the input terminal of the PID operational amplifier circuit; the output terminals of both the PID operational amplifier circuit and the triangular wave generation circuit are connected to the input terminal of the comparator circuit; the output terminal of the comparator circuit is connected to the input terminal of the motor drive circuit; the input terminal of the frequency-to-voltage conversion circuit is connected to the output terminal of the motor encoder, and its output terminal is connected to the input terminal of the PID operational amplifier circuit. This utility model's non-programmable electromagnetic tracking vehicle can achieve speed closed-loop control, can adapt well to various complex scenarios, and has strong adaptability and practicality.

Description

Technical Field

[0001] This utility model belongs to the field of intelligent vehicle control, specifically relating to a non-programmable electromagnetic tracking vehicle with a speed closed loop. Background Technology

[0002] As a typical application in the field of automation control and intelligent mobility, electromagnetic tracking vehicles are widely used in teaching experiments, warehouse inspection, automated transportation and other scenarios. Their working principle is to achieve the function of traveling along a preset track by sensing the alternating magnetic field laid on the ground (usually generated by 5-20kHz alternating current).

[0003] Existing electromagnetic tracking vehicles can be divided into two categories according to their control methods:

[0004] One type is the programmable control car, which relies on a microcontroller (such as Arduino or STM32) as its control hub. During operation, the car collects magnetic field signals through electromagnetic sensors, which are then converted into digital signals by the microcontroller's analog-to-digital converter (ADC) for digital signal processing. The programmed logic (such as a PID algorithm) calculates the speed and direction control parameters, ultimately outputting a PWM signal to drive the motor. While this type of car offers high control precision, it has significant drawbacks: firstly, it requires an additional microcontroller and peripheral circuitry, resulting in higher hardware costs; secondly, its reliance on programming to implement control logic demands strong software design skills from the user, making it unsuitable for low-cost, low-barrier-to-entry applications (such as basic education experiments or simple line-following devices).

[0005] Another type is the non-programmable car, which uses pure hardware circuitry to achieve the tracking function. It requires no microcontroller or programming. Typically, it collects magnetic field signals through electromagnetic sensors (such as coil inductors), amplifies and compares these signals via analog circuits (such as operational amplifiers), and then directly outputs control signals to drive the motor. While this type of car is lower in cost and simpler in structure, it generally uses an open-loop control method. This means the motor speed is adjusted only by a fixed voltage or a simple circuit, and cannot be adjusted in real time according to changes in the trajectory (such as curves or fluctuations in road resistance). When encountering complex scenarios (such as sudden changes in trajectory curvature or uneven ground friction), it is prone to speed fluctuations, trajectory deviations, or even loss of control. Its adaptability and stability are poor, making it difficult to meet the requirements of tracking accuracy and driving smoothness in practical applications.

[0006] Therefore, how to achieve closed-loop speed control of an electromagnetic tracking vehicle through pure hardware circuits without relying on microcontroller programming, in order to reduce costs, simplify operation, and improve its adaptability and stability in complex scenarios, has become a technical problem that urgently needs to be solved in this field. Utility Model Content

[0007] To overcome the shortcomings of existing technologies, this invention provides a non-programmable electromagnetic tracking vehicle with a closed-loop speed control. This non-programmable electromagnetic tracking vehicle can achieve a closed-loop speed control for electromagnetic tracking vehicles, and can adapt well to various complex scenarios, exhibiting strong adaptability and practicality.

[0008] The technical solution of this utility model to solve the above-mentioned technical problems is:

[0009] A non-programmable electromagnetic tracking vehicle with a speed closed loop includes an electromagnetic tracking vehicle and a control device mounted on the electromagnetic tracking vehicle for controlling the left and right wheels of the vehicle. The control device consists of two sets: a first control device and a second control device. The first control device controls the left wheel, and the second control device controls the right wheel.

[0010] The control device includes an LC parallel resonant circuit, a multi-stage amplifier circuit, a PID operational amplifier circuit, a comparator circuit, a motor drive circuit, a frequency-to-voltage conversion circuit, and a triangular wave generation circuit.

[0011] The output terminal of the LC parallel resonant circuit is connected to the input terminal of the multi-stage amplifier circuit.

[0012] The output terminal of the multi-stage amplifier circuit is connected to the first input terminal of the PID operational amplifier circuit.

[0013] The output terminal of the PID operational amplifier circuit is connected to the first input terminal of the comparator circuit.

[0014] The output terminal of the triangular wave generating circuit is connected to the second input terminal of the comparator circuit.

[0015] The output terminal of the comparator circuit is connected to the input terminal of the motor drive circuit;

[0016] The input terminal of the frequency-to-voltage conversion circuit is connected to the output terminal of the motor encoder in the motor drive circuit, and the output terminal is connected to the second input terminal of the PID operational amplifier circuit.

[0017] Preferably, the multi-stage amplifier circuit includes a first-stage amplifier circuit, a second-stage amplifier circuit, a third-stage amplifier circuit, and a fourth-stage amplifier circuit. The first-stage amplifier circuit includes a non-inverting amplifier circuit and a peak hold circuit. The second-stage amplifier circuit adopts a non-inverting input amplifier circuit based on an integrated operational amplifier. The third-stage amplifier circuit adopts a differential amplifier circuit. The fourth-stage amplifier circuit adopts a non-inverting summation operation circuit.

[0018] Preferably, the amplification factor of the second-stage amplifier circuit is less than or equal to 50 times.

[0019] Preferably, the second-stage amplifier circuit includes an LM358 chip and its peripheral circuitry.

[0020] Preferably, the PID operation circuit is composed of a differential amplifier circuit and a PID calculation circuit.

[0021] Preferably, the comparator circuit includes an LM393 chip and its peripheral circuitry.

[0022] Preferably, the frequency-to-voltage conversion circuit includes an LM331 chip and its peripheral circuitry.

[0023] Preferably, the triangular wave generating circuit uses the NE555DR chip and its peripheral circuits.

[0024] Preferably, the motor drive circuit adopts a half-bridge structure.

[0025] Preferably, a MOSFET driver chip is used.

[0026] The working principle of this non-programmable electromagnetic tracking vehicle with speed closed-loop is as follows:

[0027] The alternating magnetic field signal of the ground magnetic strip is detected by an LC parallel resonant circuit. The magnetic field strength is converted into a resonant voltage signal and transmitted to a multi-stage amplifier circuit. The multi-stage amplifier circuit amplifies the resonant voltage signal to eliminate interference and enhance signal stability. The amplified resonant voltage signal is then transmitted to a PID operational amplifier circuit. Simultaneously, a frequency-to-voltage conversion circuit acquires the speed measurement signal output by the motor encoder in the motor drive module, converts it into an actual speed voltage signal corresponding to the actual speed, and transmits it to the PID operational amplifier circuit. The PID operational amplifier circuit receives the amplified resonant voltage signal and superimposes it with the actual speed voltage signal to form a comprehensive driving state characterizing the non-programmable electromagnetic tracking vehicle (i.e., comprehensively reflecting the "tracking direction deviation + actual running speed" of the corresponding wheel). The actual state voltage signal is used; combined with the externally input target speed reference voltage, the error value between the actual state voltage and the target speed reference voltage is calculated. Through PID calculation, which uses a proportional element to quickly respond to the error, an integral element to eliminate static deviation, a derivative element to suppress overshoot, and a predictive change trend, a stable regulating voltage signal is output to the comparator circuit. In addition, a triangular wave generation circuit generates a 1KHz triangular wave signal as a reference and inputs it into the comparator circuit. The comparator circuit compares the regulating voltage signal output by the PID operational amplifier circuit with the triangular wave signal and outputs a 1KHz PWM signal. The motor drive circuit receives this PWM signal, amplifies it, and drives the corresponding drive motor to operate, realizing stable driving and speed closed-loop control of the non-programmable electromagnetic tracking car along the magnetic strip track.

[0028] Based on the above working principle, since the system is equipped with two independent control devices, the left and right wheels can be controlled separately. Therefore, the speed of the two wheels can be precisely controlled through the independent PID closed loop dedicated to the left and right wheels. At the same time, the PID operational amplifier circuit will combine the tracking deviation signal detected by the parallel resonant circuit to automatically superimpose the differential adjustment effect on the target speed reference. In the end, it can ensure that the car can stably follow the track of the ground magnetic strip and achieve the goal of closed-loop control of the overall speed.

[0029] Compared with the prior art, this utility model has the following advantages and beneficial effects:

[0030] 1. The non-programmable electromagnetic tracking car of this utility model achieves closed-loop speed control of the electromagnetic tracking car by adding PID operational amplifier circuit and frequency-voltage conversion circuit to the hardware circuit without relying on microcontroller programming, so as to reduce costs and simplify operation. At the same time, the non-programmable electromagnetic tracking car of this utility model can adapt well to various complex scenarios and has strong adaptability and practicality.

[0031] 2. The non-programmable electromagnetic tracking vehicle of this utility model is equipped with two independent control devices, which can control the left and right wheels separately. Therefore, the speed of the two wheels can be precisely controlled through the dedicated independent PID closed loop of the left and right wheels. At the same time, the PID operational amplifier circuit will combine the tracking deviation signal detected by the parallel resonant circuit to automatically superimpose the differential speed adjustment effect on the target speed reference. In the end, it can ensure that the non-programmable electromagnetic tracking vehicle can stably follow the track of the ground magnetic strip and achieve the goal of closed-loop control of the overall speed. Attached Figure Description

[0032] Figure 1 This is a structural block diagram of the control device in the speed-closed-loop non-programmable electromagnetic tracking vehicle of this utility model.

[0033] Figure 2 This is the circuit diagram of an LC parallel resonant circuit.

[0034] Figure 3 This is the circuit schematic of the first-stage amplifier circuit.

[0035] Figure 4 This is the circuit schematic of the second-stage amplifier circuit.

[0036] Figure 5 This is the circuit schematic of the third-stage amplifier circuit.

[0037] Figure 6 This is the circuit schematic of the fourth-stage amplifier circuit.

[0038] Figure 7 This is the circuit schematic of a PID operational amplifier circuit.

[0039] Figure 8 This is the circuit schematic of a comparator circuit.

[0040] Figure 9 This is the circuit schematic of a frequency-to-voltage conversion circuit.

[0041] Figure 10 This is a circuit diagram of the NE555DR chip and its peripheral circuits in a triangular wave generation circuit.

[0042] Figure 11 This is a circuit diagram of the feedback loop in a triangular wave generation circuit.

[0043] Figure 12 This is the circuit diagram of the motor drive circuit. Detailed Implementation

[0044] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the implementation of the present invention is not limited thereto.

[0045] like Figures 1-12 As shown, the non-programmable electromagnetic tracking vehicle with speed closed-loop of this utility model includes an electromagnetic tracking vehicle and a control device installed on the electromagnetic tracking vehicle for controlling the left and right wheels of the electromagnetic tracking vehicle; the control device consists of two sets, namely a first control device and a second control device, wherein the first control device is used to control the left wheel; and the second control device is used to control the right wheel.

[0046] like Figure 1 As shown, the control device includes an LC parallel resonant circuit, a multi-stage amplifier circuit, a PID operational amplifier circuit, a comparator circuit, a motor drive circuit, a frequency-to-voltage conversion circuit, and a triangular wave generation circuit.

[0047] like Figure 2 As shown, the LC parallel resonant circuit (L is an inductor and C is a capacitor) is used to sense alternating magnetic field signals and convert the magnetic field strength into a resonant voltage signal;

[0048] In this embodiment, the LC parallel resonant circuit is as follows: Figure 2 As shown, the frequency selection formula is:

[0049] ;

[0050] Among them, the frequency of the signal source For a frequency of 20kHz, a 10mH I-shaped inductor is chosen for the inductor L. From this, C = 6.33nF can be calculated. For ease of selection, the capacitance C is 6.8nF. Furthermore, based on the above frequency selection formula, parallel resonant circuits with alternating magnetic fields of different frequencies can also be designed by simply selecting inductor L and capacitor C with different parameter values.

[0051] like Figures 3-6 As shown, the multi-stage amplifier circuit is used to amplify the resonant voltage output by the LC parallel resonant circuit in four stages. The multi-stage amplifier circuit includes a first-stage amplifier circuit, a second-stage amplifier circuit, a third-stage amplifier circuit, and a fourth-stage amplifier circuit.

[0052] like Figure 3 As shown, the first-stage amplifier circuit uses a non-inverting amplifier circuit. Based on the virtual short characteristic of the operational amplifier, it can be known that... The voltage across the terminals is equal to VIN, therefore the output voltage is... :

[0053] ;

[0054] Adjust the potentiometer according to the input voltage. By determining the value of the amplification factor, the desired amplification factor can be obtained; and thus the desired output voltage can be obtained.

[0055] Assuming input voltage Adjust the potentiometer Then the magnification factor Output voltage Therefore, different amplification factors can be obtained by adjusting the potentiometer.

[0056] Furthermore, the non-inverting amplifier circuit is immediately followed by a peak hold circuit. The basic principle of the peak hold circuit is to utilize the unidirectional conduction characteristic of diodes and the energy storage characteristic of capacitors. The input signal of the peak hold circuit is the signal being detected, and the output is, under ideal conditions, a stable voltage (the peak value of the AC signal). Assuming the input signal is a sine wave, during the positive half-cycle of the input, Zener diode U4 is turned on and Zener diode U5 is turned off, at which time capacitor C5 is charged. During the negative half-cycle of the input, Zener diode U4 is turned off and Zener diode U5 is turned on, at which time capacitor C5 is discharged through resistor R21. Since the resistance value of the selected resistor R21 (51kΩ) is relatively large, the discharge speed is relatively slow, so the voltage stored in capacitor C5 will not be completely discharged. After several cycles, the charging and discharging speed of capacitor C5 will reach a balance, and the output voltage will be roughly maintained near the peak voltage of the input signal. Even if there are relatively small fluctuations, it can still be approximated as a DC voltage.

[0057] like Figure 4As shown, the second-stage amplifier circuit is a non-inverting input amplifier circuit built based on an integrated operational amplifier, with its amplification factor set to no more than 50 times. Because the input is a smoothly fluctuating voltage signal, a common operational amplifier chip can be used, such as the commonly used LM358 chip, which can further reduce costs. The amplification factor of the non-inverting input amplifier circuit is:

[0058] ;

[0059] like Figure 5 As shown, the third-stage amplifier circuit employs a differential amplifier circuit, specifically a subtractor composed of operational amplifiers, wherein the voltage at the positive input terminal... :

[0060] ;

[0061] Depend on The output voltage of the op-amp can be obtained. :

[0062] ;

[0063] From the virtual short and virtual open characteristics of the operational amplifier, it can be known that the output voltage It can be represented as:

[0064] ;

[0065] Where R12=R13=R14; therefore, the output voltage can be adjusted by adjusting the resistance of potentiometer PR2.

[0066] like Figure 6 As shown, the fourth-stage amplifier circuit is based on a same-direction summation operation circuit;

[0067] Depend on The output voltage of the op-amp can be obtained. :

[0068] ;

[0069] The positive input performs the summation of two input signals, by... Obtain the voltage at the positive input terminal at this time. :

[0070] ;

[0071] Since R8=R9=R10=R11, and since ,therefore ,so .

[0072] like Figure 7As shown, the PID operation circuit is composed of a differential amplifier circuit and a PID calculation circuit, wherein,

[0073] The differential amplifier circuit is a subtractor composed of operational amplifiers, and the voltage at its positive input terminal is... VEL_SENSING_LEFT; by The output voltage of the op-amp can be obtained:

[0074] ;

[0075] From the virtual short and virtual open characteristics of the operational amplifier, it can be known that Therefore, the output voltage can be expressed as: ;

[0076] The output voltage can be adjusted by adjusting the resistance of potentiometer PR11.

[0077] Resistor R40 and capacitor C16 in the PID calculation circuit are mainly used to protect the circuit and maintain signal integrity. As long as the impedance of capacitor C16 is much greater than that of resistor R42 and capacitor C15, it can be ignored in the subsequent quantitative analysis calculations. In the case of high-frequency signals, capacitor C14 is equivalent to a short circuit, and the series resistor R40 can reduce the inrush current, thus protecting the circuit. The function of capacitor C16 is to limit AC gain. When the impedance of capacitor C16 is much greater than that of resistor R42 and capacitor C15, the impedance of capacitor C16 to high-frequency signals increases, thereby limiting the amplification factor of high-frequency signals to prevent excessive AC gain. When the frequency is very high, the impedance of capacitor C16 is very small. Assuming there is no limiting effect from capacitor C16, the amplification factor of high-frequency signals would be very large. Therefore, capacitor C16 allows the circuit to maintain a suitable gain at high frequencies, avoiding signal distortion and circuit instability. Assume the current in the branch containing capacitor C14 is... The current in the branch containing resistor R4 is The current in the branch containing resistor R42 and capacitor C15 is Then we have:

[0078] , ;

[0079] And because ,therefore:

[0080] .

[0081] Therefore, the voltage across capacitor C15 is:

[0082] The voltage across resistor R42 is:

[0083] ;

[0084] The output voltage is:

[0085] Wherein, the proportional term P is The integral term I is The differential term D is .

[0086] See Figure 8 The comparator circuit is used to compare the adjustment voltage of the PID operational amplifier circuit with the triangular wave signal and output a 1KHz PWM signal.

[0087] In this embodiment, the comparator circuit uses an LM393 chip, which is a dual voltage comparator. It continuously compares the level of the regulated voltage signal with the level of a triangular wave signal. When the + terminal voltage > the - terminal voltage, the output is high; when the + terminal voltage < the - terminal voltage, the output is low. When the voltage of the triangular wave signal is lower than the regulated voltage, the output is high (+5V); otherwise, the output is low (0V). Thus, the comparator circuit outputs a square wave pulse, the pulse width (duty cycle) of which is proportional to the voltage magnitude of the regulated signal (PID_OUT).

[0088] like Figure 9 As shown, the frequency-to-voltage conversion circuit uses an LM331 chip to convert the pulse frequency in the drive motor into a voltage signal. The higher the pulse frequency, the higher the voltage. The capacitor C93 cannot be too small; otherwise, when the falling edge of the pulse signal arrives, pin 6 of the LM331 chip will not provide a sufficiently large peak pulse, thus failing to trigger the input comparator. However, if it is too large, it will reduce the circuit's anti-interference capability. The low-pass filter composed of resistor R97 and capacitor C41 can reduce the output voltage ripple to less than 10mV. Increasing the value of CL helps reduce ripple but will reduce the circuit's response speed. Pin 2 of the LM331 chip can be connected in series with an adjustable resistor to adjust the error caused by resistors R97, R92, and capacitor C39. Therefore, the values ​​of various parameters need to be considered comprehensively. The formula for converting frequency to voltage in the frequency-to-voltage conversion circuit is:

[0089] .

[0090] See Figure 10 and Figure 11 The triangular wave generating circuit is used to generate a 1kHz triangular wave signal;

[0091] In this embodiment, the triangular wave generation circuit uses an NE555DR chip. This NE555DR chip is used to generate square wave signals with a specific period and duty cycle. The frequency and duty cycle of the output square wave can be adjusted by selecting the parameters of the components.

[0092] The period of the output signal is: ;

[0093] The frequency of the output signal is: ;

[0094] Duty cycle of the output signal: ;

[0095] The frequency can be changed by adjusting resistors R33, R34, PR8, and capacitor C11. Adjusting resistors R34 and PR8 can adjust the duty cycle. The final selected square wave frequency is about 1kHz and the duty cycle is about 50%. Therefore, R33 = 1kΩ, R34 = 51kΩ, PR8 = about 20.5kΩ, and C11 = 10nF.

[0096] A resistor R37 is connected in parallel in the feedback loop mainly to limit the DC gain of the operational amplifier and ensure the integrity of the waveform without distortion. The effect of R37 can be ignored in the calculation.

[0097] From the virtual open circuit characteristic of the op-amp, we can obtain:

[0098] ;

[0099] Therefore, the output voltage can be expressed as:

[0100] ;

[0101] From the virtual short property of the op-amp, we can obtain:

[0102] ;

[0103] In practical applications Since it is a fixed value, the output voltage can be simplified to:

[0104] ;

[0105] See Figure 12 The motor drive circuit is used to receive the PWM signal output by the comparator circuit and amplify its power to drive the motor on the corresponding side to operate.

[0106] In this embodiment, the motor drive circuit adopts a half-bridge structure. If the power of the drive motor is relatively large, a MOSFET driver chip can be used. Here, as an example, a common transistor + low-power motor structure is used, with a peak current not exceeding 1.5A. It should be noted that a fast recovery freewheeling diode needs to be connected in parallel across the drive motor to prevent the circuit from burning out due to motor stall. From the actual tracking test results, the modified speed closed-loop non-programmable electromagnetic tracking circuit is stable, easy to use, and effective.

[0107] See Figures 1-12 The working principle of this novel speed-closed-loop non-programmable electromagnetic tracking vehicle is as follows:

[0108] The alternating magnetic field signal of the ground magnetic strip is detected by an LC parallel resonant circuit, and the magnetic field strength is converted into a resonant voltage signal and transmitted to a multi-stage amplifier circuit. The multi-stage amplifier circuit amplifies the resonant voltage signal and transmits it to a PID operational amplifier circuit. Simultaneously, a frequency-to-voltage conversion circuit acquires the speed measurement signal output from the motor encoder in the motor drive module, converts it into an actual speed voltage signal corresponding to the actual speed, and transmits it to the PID operational amplifier circuit. The PID operational amplifier circuit receives the amplified resonant voltage signal, superimposes it with the actual speed voltage signal to form an actual state voltage signal characterizing the comprehensive driving state of the non-programmable electromagnetic tracking vehicle. Combined with an externally input target speed reference voltage, the error value between the actual state voltage and the target speed reference voltage is calculated, and an adjustment voltage signal is output to a comparator circuit. A triangular wave generation circuit generates a 1kHz triangular wave signal and inputs it to the comparator circuit. The comparator circuit compares the adjustment voltage signal output from the PID operational amplifier circuit with the triangular wave signal and outputs a 1kHz PWM signal. The motor drive circuit receives this PWM signal. The signal, after being amplified, drives the corresponding drive motor to operate, thereby enabling the non-programmable electromagnetic tracking vehicle to travel stably along the magnetic strip track and achieve closed-loop speed control.

[0109] The above are preferred embodiments of the present utility model, but the embodiments of the present utility model are not limited to the above content. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present utility model shall be considered equivalent substitutions and shall be included within the protection scope of the present utility model.

Claims

1. A non-programmable electromagnetic tracking vehicle with a closed-loop speed control, characterized in that, The system includes an electromagnetic tracking vehicle and a control device mounted on the vehicle for controlling the left and right wheels. The control device consists of two sets: a first control device and a second control device. The first control device controls the left wheel, and the second control device controls the right wheel. The control device includes an LC parallel resonant circuit, a multi-stage amplifier circuit, a PID operational amplifier circuit, a comparator circuit, a motor drive circuit, a frequency-to-voltage conversion circuit, and a triangular wave generation circuit. The output terminal of the LC parallel resonant circuit is connected to the input terminal of the multi-stage amplifier circuit. The output terminal of the multi-stage amplifier circuit is connected to the first input terminal of the PID operational amplifier circuit. The output terminal of the PID operational amplifier circuit is connected to the first input terminal of the comparator circuit. The output terminal of the triangular wave generating circuit is connected to the second input terminal of the comparator circuit. The output terminal of the comparator circuit is connected to the input terminal of the motor drive circuit; The input terminal of the frequency-to-voltage conversion circuit is connected to the output terminal of the motor encoder in the motor drive circuit, and the output terminal is connected to the second input terminal of the PID operational amplifier circuit.

2. The non-programmable electromagnetic tracking vehicle with speed closed-loop as described in claim 1, characterized in that, The multi-stage amplifier circuit includes a first-stage amplifier circuit, a second-stage amplifier circuit, a third-stage amplifier circuit, and a fourth-stage amplifier circuit. The first-stage amplifier circuit includes a non-inverting amplifier circuit and a peak hold circuit. The second-stage amplifier circuit adopts a non-inverting input amplifier circuit based on an integrated operational amplifier. The third-stage amplifier circuit adopts a differential amplifier circuit. The fourth-stage amplifier circuit adopts a non-inverting summation operation circuit.

3. The non-programmable electromagnetic tracking vehicle with speed closed-loop as described in claim 2, characterized in that, The amplification factor of the second-stage amplifier circuit is less than or equal to 50 times.

4. The non-programmable electromagnetic tracking vehicle with speed closed-loop as described in claim 2, characterized in that, The second-stage amplifier circuit includes the LM358 chip and its peripheral circuitry.

5. The non-programmable electromagnetic tracking vehicle with speed closed-loop as described in claim 1, characterized in that, The PID operation circuit consists of a differential amplifier circuit and a PID calculation circuit.

6. The non-programmable electromagnetic tracking vehicle with speed closed-loop as described in claim 1, characterized in that, The comparator circuit includes an LM393 chip and its peripheral circuitry.

7. The non-programmable electromagnetic tracking vehicle with speed closed-loop as described in claim 1, characterized in that, The frequency-to-voltage conversion circuit includes an LM331 chip and its peripheral circuitry.

8. The non-programmable electromagnetic tracking vehicle with speed closed-loop as described in claim 1, characterized in that, The triangular wave generation circuit uses the NE555DR chip and its peripheral circuits.

9. The non-programmable electromagnetic tracking vehicle with speed closed-loop as described in claim 1, characterized in that, The motor drive circuit adopts a half-bridge structure.

10. The non-programmable electromagnetic tracking vehicle with speed closed-loop as described in claim 1, characterized in that, The chip is driven by a MOSFET.

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