A control method of a jacking type AGV based on a permanent magnet motor

Abstract

A control method of a lifting type AGV based on a permanent magnet motor, comprising the following steps: a plurality of image acquisition devices are arranged in a line through which the AGV passes, and the image acquisition devices are used to acquire a orthographic projection image of the AGV when the AGV carries goods; in the orthographic projection image, a midpoint of the goods is acquired, a vertical distance and a horizontal distance are acquired; the weight of the goods is acquired, and according to the weight of the goods and the horizontal distance, an adjustment coefficient of the rotational inertia is acquired in a preset adjustment coefficient table; according to the vertical distance and the weight of the goods, a preliminary rotational inertia of the goods is acquired; the angular velocity V1 of the chassis motor is acquired, and the angular velocity V2 of the tray motor is calculated according to the angular velocity V1 and the final rotational inertia; through accurate calculation and real-time adjustment, the present application can reduce the carrying failure and safety hazards caused by inaccurate goods position or mismatched rotational inertia, thereby improving the carrying efficiency and safety. At the same time, intelligent control also reduces the need for manual intervention and reduces labor costs.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of permanent magnet motor adjustment, and particularly relates to a control method of a jacking AGV based on a permanent magnet motor. BACKGROUND

[0002] The jacking AGV is an automatic guided vehicle and has the function of jacking up and down. In use, the jacking AGV is generally driven to move to the top of a goods shelf, and then the tray at the top of the AGV is driven to jack up the goods shelf and the goods on the goods shelf.

[0003] In order to facilitate the stacking of goods, the jacking AGV generally has the function of keeping the pose of the goods, that is, while controlling the chassis to steer the AGV, the tray is controlled to rotate in the opposite direction, so that the pose of the goods is kept unchanged.

[0004] However, the weight of the goods on the AGV is uncertain and changes with the working condition, so the friction and inertia also change constantly, and the actual speed and the reference speed issued will have a large deviation and fluctuation when the AGV body itself runs on different road surfaces (such as concave-convex and insufficient friction). In this case, the control stability and precision of the top load tray cannot be guaranteed, and the pose of the goods will change. When stacking, the change in the pose of the goods will cause the goods to be stacked in an incorrect manner, and manual intervention is required at this time, which greatly affects the work efficiency and the stability of the overall structure of the stacked goods. SUMMARY

[0005] In view of the above defects, the present application provides a control method of a jacking AGV based on a permanent magnet motor, which solves the problems of handling errors and safety hazards caused by the inability to keep the pose of the goods or the mismatch of the rotational inertia.

[0006] To achieve the above purpose, the present application adopts the following technical scheme: a control method of a jacking AGV based on a permanent magnet motor, comprising the following steps:

[0007] Step S1: multiple image acquisition devices are arranged on the route through which the AGV passes, and the image acquisition devices are used to acquire the orthographic projection image of the AGV when the AGV is carrying goods;

[0008] Step S2: in the orthographic projection image, the midpoint of the goods is acquired, and the vertical distance and the horizontal distance between the midpoint of the tray on the AGV and the midpoint of the goods are acquired;

[0009] Step S3: the weight of the goods is acquired, and the adjustment coefficient of the rotational inertia is acquired in a preset adjustment coefficient table according to the weight of the goods and the horizontal distance;

[0010] obtaining a preliminary rotational inertia of the cargo according to the vertical distance and the weight of the cargo;

[0011] adjusting the preliminary rotational inertia according to an adjustment coefficient of the rotational inertia to obtain a final rotational inertia;

[0012] Step S4: obtaining an angular velocity V1 of the chassis motor, and calculating an angular velocity V2 of the tray motor according to the angular velocity V1 and the final rotational inertia;

[0013] Step S5: selecting corresponding d-axis current and q-axis current according to the size of the angular velocity V2 of the tray motor.

[0014] Preferably, the specific steps in step S2 are as follows:

[0015] processing the front projection image using Otsu law to obtain a threshold value for binarization of the front projection image;

[0016] binarizing the front projection image based on the threshold value to obtain a second picture;

[0017] performing contour extraction in the second picture;

[0018] obtaining a rectangle with the longest horizontal direction in the second picture as a first rectangle;

[0019] taking a rectangle with the largest area connected above the first rectangle as a second rectangle, and taking a rectangle with the longest horizontal direction connected below the first rectangle as a third rectangle;

[0020] respectively obtaining the midpoints of the second rectangle and the third rectangle, taking the midpoint of the second rectangle as the midpoint of the cargo, and taking the midpoint of the third rectangle as the midpoint of the tray.

[0021] Preferably, the calculation formula of the preliminary rotational inertia in step S3 is as follows:

[0022] ;

[0023] wherein m is the weight of the cargo, and L is the vertical distance between the midpoint of the tray above and the midpoint of the cargo.

[0024] Preferably, the calculation formula of the angular velocity V2 in step S4 is as follows:

[0025] ;

[0026] wherein is the final rotational inertia, is the q-axis current of the chassis motor, is the maximum torque of the tray motor, B is the viscous friction coefficient, and C is an integral constant, Torque of the motor after the pallet is loaded with goods.

[0027] Preferably, the specific steps of step S5 are as follows:

[0028] It is judged whether the angular velocity V2 is greater than the speed threshold value, if less, the current control mode of MTPA is adopted to generate the corresponding d-axis and q-axis currents;

[0029] If greater, the d-axis current is obtained according to the operating parameters, design parameters and target speed of the motor, and the q-axis current limit value is obtained according to the maximum current and the d-axis current.

[0030] Preferably, the step of obtaining the d-axis current according to the operating parameters, design parameters and target speed of the motor is specifically as follows:

[0031] The given current of the q-axis is obtained in real time , the given current is input into a low-pass filter to obtain a first parameter .

[0032] The feedback current of the q-axis is obtained in real time , the feedback current is input into a low-pass filter to obtain a second parameter .

[0033] The difference E between the first parameter and the second parameter is obtained, and the difference E is taken as the input of the PI controller to obtain the current feedback given item D1;

[0034] The amplification coefficient Kc of the feedforward given item of the field weakening current is calculated according to the rated current and the rated speed ;

[0035] The current speed increment of the current field weakening is obtained, and the speed increment is adjusted by the amplification coefficient Kc to obtain the current feedback given item D2;

[0036] The d-axis current is obtained by adding the feedback given item D1 and the feedforward given item D2.

[0037] Preferably, the formula for obtaining the current feedback given item D1 is specifically as follows:

[0038] ;

[0039] Where t is time, and are the proportional gain coefficient and the integral gain coefficient in the PI controller, respectively;

[0040] The acquisition formula for obtaining the amplification coefficient Kc is specifically as follows:

[0041] ,

[0042] wherein is a rated current, is a rated rotating speed;

[0043] The acquisition formula for obtaining the feedforward given item D2 is specifically as follows:

[0044] ; wherein, is a rotating speed threshold.

[0045] Preferably, the acquisition formula for the limiting value of the q-axis current is as follows:

[0046] ;

[0047] wherein is a maximum output current, is a d-axis current.

[0048] A control system of a jacking AGV based on a permanent magnet motor, using the control method of the jacking AGV based on the permanent magnet motor, comprising an image acquisition module, a determination module, a coefficient module, an adjustment module and a control module.

[0049] The image acquisition module is used for setting a plurality of image acquisition devices in a line through which the AGV passes, and the image acquisition devices are used for acquiring a front projection image of the AGV when carrying goods;

[0050] The determination module is used for acquiring a midpoint of the goods and a vertical distance and a horizontal distance between the midpoint of the goods and a midpoint of a tray on the AGV in the front projection image;

[0051] The coefficient module is used for acquiring a weight of the goods, and acquiring an adjustment coefficient of the rotational inertia in a preset adjustment coefficient table according to the weight of the goods and the horizontal distance;

[0052] acquiring a preliminary rotational inertia of the goods according to the vertical distance and the weight of the goods;

[0053] adjusting the preliminary rotational inertia according to the adjustment coefficient of the rotational inertia to obtain a final rotational inertia;

[0054] The adjustment module is used for acquiring an angular velocity V1 of a chassis motor, and calculating an angular velocity V2 of a tray motor according to the angular velocity V1 and the final rotational inertia;

[0055] The control module is used for selecting corresponding d-axis currents and q-axis currents according to the size of the angular velocity V2 of the tray motor.

[0056] One of the above technical solutions has the following advantages or beneficial effects: the present application can reduce the carrying errors and safety hazards caused by inaccurate cargo position or mismatched rotational inertia through accurate calculation and real-time adjustment, thereby improving the carrying efficiency and safety. At the same time, intelligent control also reduces the need for manual intervention and reduces labor costs. BRIEF DESCRIPTION OF DRAWINGS

[0057] Fig. 1 is a flowchart of an embodiment of the method of the present application.

[0058] Fig. 2 is a structural schematic diagram of an embodiment of the system of the present application.

[0059] Fig. 3 is a profile diagram of the orthographic projection of an embodiment of the present application. DETAILED DESCRIPTION

[0060] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the accompanying drawings, in which the same or similar reference numerals represent the same or similar elements throughout. The embodiments described below by reference to the accompanying drawings are exemplary and are for the purpose of explanation only, and should not be understood as limiting the present application.

[0061] In the description of the embodiments of the present application, the terms "first", "second" are used only for the purpose of description, and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0062] In addition, the terms "first", "second" are used only for the purpose of description, and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise stated, the meaning of "multiple" is two or more. The specific meaning of the above terms in the present application can be understood in specific cases by those skilled in the art.

[0063] As shown in Figs. 1-3 A control method of a lifting AGV based on a permanent magnet motor, comprising the following steps:

[0064] Step S1: A plurality of image acquisition devices are arranged in the line through which the AGV passes, and the image acquisition devices are used to acquire the orthographic projection image of the AGV when carrying the goods.

[0065] Step S2: In the orthographic projection image, the midpoint of the goods is obtained, and the vertical distance and the horizontal distance between the midpoint of the pallet on the AGV and the midpoint of the goods are obtained;

[0066] Step S3: The weight of the goods is obtained, and the adjustment coefficient of the rotational inertia is obtained in the preset adjustment coefficient table according to the weight of the goods and the horizontal distance;

[0067] The preliminary rotational inertia of the goods is obtained according to the vertical distance and the weight of the goods;

[0068] The final rotational inertia is obtained by adjusting the preliminary rotational inertia according to the adjustment coefficient of the rotational inertia;

[0069] Step S4: The angular velocity V1 of the chassis motor is obtained, and the angular velocity V2 of the pallet motor is calculated according to the angular velocity V1 and the final rotational inertia;

[0070] Step S5: The corresponding d-axis current and q-axis current are selected according to the size of the angular velocity V2 of the pallet motor.

[0071] Before the AGV lifts the goods, the position is aligned according to the sensing point on the goods shelf, so that the center of the pallet is aligned with the center of the goods shelf. However, there may be alignment deviation. At this time, since the center of gravity of the goods is not located on the same vertical line as the center of the pallet, when the pallet rotates, it will be affected by the weight of the goods above, so that the rotation angle of the pallet and the chassis is not the same at the same rotation speed, so that the goods cannot maintain the same pose relative to the ground.

[0072] Therefore, in the present application, a plurality of image acquisition devices are arranged in the use space of the AGV, wherein the image acquisition device can be a camera. When the AGV is running, the orthographic projection image of the AGV when carrying goods is obtained, and then the orthographic projection image is analyzed to obtain the vertical distance and the horizontal distance between the midpoint of the pallet on the AGV and the midpoint of the goods. The vertical distance and the horizontal distance can be used to obtain the adjustment coefficient of the corresponding rotational inertia and the preliminary rotational inertia. The adjustment coefficient of the rotational inertia can be obtained through a plurality of experiments, and the experimental data can form the adjustment coefficient table as shown below.

[0073]

[0074] After selecting the corresponding adjustment coefficient of the rotational inertia through the weight of the goods and the horizontal distance, the final rotational inertia can be obtained by multiplying the preliminary rotational inertia by the adjustment coefficient of the rotational inertia.

[0075] The final rotational inertia is a factor affecting rotation of the tray, and the angular velocity V2 can be adjusted through the final rotational inertia, so that the tray and the base plate can rotate at different angular velocities while maintaining the same angle after rotation.

[0076] However, the adjusted angular velocity V2 may exceed the rotation threshold, causing the tray motor to enter the field weakening control stage, so at this time, different current control methods are selected according to the size of the angular velocity V2.

[0077] The present application can reduce handling errors and safety hazards caused by inaccurate cargo position or mismatched rotational inertia through accurate calculation and real-time adjustment, thereby improving handling efficiency and safety. At the same time, intelligent control also reduces the need for manual intervention and reduces labor costs.

[0078] Preferably, the specific steps in step S2 are as follows:

[0079] The Otsu law is used to process the front projection image to obtain a threshold value for binarizing the front projection image;

[0080] The front projection image is binarized based on the threshold value to obtain a second picture;

[0081] Contour extraction is performed in the second picture;

[0082] The longest rectangle in the horizontal direction of the second picture is obtained as a first rectangle;

[0083] The largest rectangle connected above the first rectangle is taken as a second rectangle, and the longest rectangle in the horizontal direction connected below the first rectangle is taken as a third rectangle;

[0084] The midpoints of the second rectangle and the third rectangle are obtained, respectively, and the midpoint of the second rectangle is taken as the midpoint of the goods, and the midpoint of the third rectangle is taken as the midpoint of the tray.

[0085] Since there is a background picture in the front projection image, in order to avoid the influence of the background picture on the vertical distance and the horizontal distance, the front projection image is first binarized to obtain a second picture, and the background picture is removed in the second picture. Reduce the influence of external pictures. As shown in Fig. 3 As shown in the drawings, the carrying shelf is generally wider than the goods, and the AGV has a small volume. Therefore, in the extracted contour, the longest rectangle in the horizontal direction can quickly find the shelf (first rectangle), and the shelf can quickly find the goods above and below it (second rectangle) and the tray (third rectangle).

[0086] It is worth noting that when the image acquisition device takes a picture of the AGV, the AGV reaches the corresponding shooting point, and the image acquisition device takes a picture. In this way, the relationship between the pixel points in each orthographic image and the actual distance is unique, so that the actual horizontal distance and vertical distance can be better determined according to the midpoints of the second rectangle and the third rectangle.

[0087] Preferably, the calculation formula of the preliminary rotational inertia in step S3 is as follows:

[0088] ;

[0089] Where m is the weight of the goods, and L is the vertical distance between the midpoint of the upper tray and the midpoint of the goods.

[0090] Preferably, the calculation formula of the angular velocity V2 in step S4 is as follows:

[0091] ;

[0092] Where is the final rotational inertia, is the q-axis current of the bottom tray motor, is the maximum torque of the tray motor, B is the viscous friction coefficient, C is the integral constant, is the torque of the tray motor after loading the goods.

[0093] Preferably, the specific steps of step S5 are as follows:

[0094] Determine whether the angular velocity V2 is greater than the speed threshold value. If it is less than the speed threshold value, the current control mode of MTPA is used to generate the corresponding d-axis and q-axis currents.

[0095] If it is greater than the speed threshold value, the d-axis current is obtained according to the operating parameters, design parameters and target speed of the motor, and the q-axis current limit value is obtained according to the maximum current and the d-axis current.

[0096] When it is greater than the speed threshold value, the permanent magnet motor will enter the stage of field weakening control. At this time, in addition to ensuring the speed, the stability during turning also needs to be considered. Avoiding unstable rotation to cause the goods to deviate, thereby affecting the horizontal distance.

[0097] Preferably, the step of obtaining the d-axis current according to the operating parameters, design parameters and target speed of the motor is specifically as follows:

[0098] Real-time acquisition of the given q-axis current , the given current is input into a low-pass filter to obtain the first parameter ;

[0099] Real-time acquisition of q-axis feedback current , the feedback current is input into a low-pass filter to obtain a second parameter ;

[0100] By real-time acquisition of the given current and feedback current of the q-axis and applying a low-pass filter for processing, a more stable and accurate current parameter can be obtained. This method helps to accurately control the operation of the motor, improving stability and reliability.

[0101] Acquisition of a first parameter and the difference E between the second parameter , taking the difference E as the input of the PI controller to obtain a current feedback given item D1;

[0102] By calculating the difference E between the given current and the feedback current and taking it as the input of the PI controller, a feedback given item D1 for adjusting the current can be obtained. The PI controller can effectively reduce errors and improve the accuracy of current control.

[0103] According to the rated current and the rated speed , the amplification coefficient Kc of the feedforward given item of the field weakening current is calculated; the determination of the calculated amplification coefficient Kc is based on the rated current and the rated speed of the motor, and the speed increment is adjusted through the amplification coefficient Kc, which can ensure the motor to run in a high-efficiency and stable state.

[0104] Acquisition of the current speed increment of the field weakening, adjustment of the speed increment through the amplification coefficient Kc to obtain a current feedback given item D2;

[0105] The d-axis current is obtained by adding the feedback given item D1 and the feedforward given item D2.

[0106] In the present application, feedback control and feedforward control are combined, the d-axis current is obtained through simple addition operation, and the d-axis current can be accurately obtained without relying on complex algorithms. The feedforward given item D1 of the field weakening current can improve the speed response of the motor speed during rapid switching, and the feedback given item of the field weakening current can ensure the speed stability of the motor under heavy load. The weak magnetic control method has less calculation amount, simple structure and high running stability.

[0107] Preferably, the current feedback given item D1 is obtained according to the following formula:

[0108] ;

[0109] Where t is time, and A proportional gain coefficient and an integral gain coefficient in a PI controller, respectively;

[0110] The acquisition formula for acquiring the amplification coefficient Kc is specifically as follows:

[0111] ,

[0112] Wherein is a rated current, is a rated speed;

[0113] The acquisition formula for acquiring the feedforward given item D2 is specifically as follows:

[0114] ; wherein, is a speed threshold.

[0115] Preferably, the acquisition formula for the limit value of the q-axis current is as follows:

[0116] ;

[0117] Wherein is a maximum output current, is a d-axis current.

[0118] Since the q-axis current is directly related to the electromagnetic torque, accurate control of the q-axis current can ensure the required torque output of the motor. However, excessively high q-axis current can cause the motor to overheat or be damaged. Therefore, by limiting the maximum value of the q-axis current command, the motor can be ensured to operate within a safe range while optimizing torque output. Excessively high q-axis current can cause the motor to generate large torque fluctuations during dynamic response, affecting the stable operation of the motor. Therefore, in the present application, the q-axis current is limited by the maximum output current and the d-axis, the purpose of which is to weaken the motor magnetic field, reduce the back electromotive force under the condition of limited power input voltage, and achieve the purpose of improving the motor speed. Therefore, whether to switch the field weakening control is determined according to the angular velocity of the permanent magnet motor.

[0119] A control system of a jacking type AGV based on a permanent magnet motor, using the control method of the jacking type AGV based on the permanent magnet motor, comprising an image acquisition module, a determination module, a coefficient module, an adjustment module and a control module.

[0120] The image acquisition module is used to set a plurality of image acquisition devices in a line through which the AGV passes, and the image acquisition devices are used to acquire a front projection image of the AGV when carrying goods;

[0121] The determination module is used to acquire a midpoint of the goods and a vertical distance and a horizontal distance between the midpoint of the goods and the midpoint of the tray on the AGV in the front projection image;

[0122] The coefficient module is configured to acquire the weight of the cargo, and acquire the adjustment coefficient of the rotational inertia according to the weight of the cargo and the horizontal distance in a preset adjustment coefficient table;

[0123] acquire the preliminary rotational inertia of the cargo according to the vertical distance and the weight of the cargo;

[0124] adjust the preliminary rotational inertia according to the adjustment coefficient of the rotational inertia to obtain the final rotational inertia;

[0125] The adjustment module is configured to acquire the angular velocity V1 of the chassis motor, and calculate the angular velocity V2 of the tray motor according to the angular velocity V1 and the final rotational inertia;

[0126] The control module is configured to select the corresponding d-axis current and q-axis current according to the size of the angular velocity V2 of the tray motor.

[0127] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0128] Although the embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and cannot be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A control method for a lifting AGV based on a permanent magnet motor, characterized in that, Includes the following steps: Step S1: Set up multiple image acquisition devices along the route traversed by the AGV. The image acquisition devices are used to acquire orthographic projection images of the AGV when it is transporting goods. Step S2: In the orthographic projection image, obtain the midpoint of the goods, and obtain the vertical distance and horizontal distance between the midpoint of the pallet on the AGV and the midpoint of the goods; Step S3: Obtain the weight of the goods, and based on the weight of the goods and the horizontal distance, obtain the adjustment coefficient of rotational inertia from the preset adjustment coefficient table; The initial moment of inertia of the cargo is obtained based on the vertical distance and the weight of the cargo. The initial moment of inertia is adjusted according to the adjustment coefficient of rotational inertia to obtain the final moment of inertia; Step S4: Obtain the angular velocity V1 of the chassis motor, and calculate the angular velocity V2 of the pallet motor based on the angular velocity V1 and the final moment of inertia. Step S5: Select the corresponding d-axis current and q-axis current according to the magnitude of the angular velocity V2 of the pallet motor.

2. The control method for a lifting AGV based on a permanent magnet motor according to claim 1, characterized in that, The specific steps in step S2 are as follows: The orthographic projection image is processed using the Otsu rule to obtain the binarization threshold used for the orthographic projection image; The orthographic projection image is binarized based on a binarization threshold to obtain a second image; Contour extraction is performed on the second image; Find the longest horizontal rectangle in the second image and use it as the first rectangle; The rectangle with the largest area connected above the first rectangle is taken as the second rectangle, and the rectangle with the longest horizontal length connected below the first rectangle is taken as the third rectangle. Obtain the midpoints of the second rectangle and the third rectangle respectively. Use the midpoint of the second rectangle as the midpoint of the goods and the midpoint of the third rectangle as the midpoint of the pallet.

3. The control method for a lifting AGV based on a permanent magnet motor according to claim 1, characterized in that, The formula for calculating the initial rotational inertia in step S3 is as follows: ； Where m is the weight of the goods, and L is the vertical distance between the midpoint of the upper pallet and the midpoint of the goods.

4. The control method for a lifting AGV based on a permanent magnet motor according to claim 1, characterized in that, The formula for calculating the angular velocity V2 in step S4 is as follows: ； in For the final rotational inertia, The q-axis current of the chassis motor B is the maximum torque of the pallet motor, C is the coefficient of viscous friction, and C is the integral constant. This refers to the torque of the pallet motor after the load of goods is applied.

5. The control method for a lifting AGV based on a permanent magnet motor according to claim 1, characterized in that, The specific steps of step S5 are as follows: Determine if the angular velocity V2 is greater than the velocity threshold. If it is less than the threshold, use the MTPA current control method to generate the corresponding d-axis and q-axis currents. If the value is greater than the target speed, the d-axis current is obtained based on the motor's operating parameters, design parameters, and target speed. The q-axis current limit is obtained based on the maximum current and the d-axis current.

6. The control method for a lifting AGV based on a permanent magnet motor according to claim 5, characterized in that, The specific steps for obtaining the d-axis current based on the motor's operating parameters, design parameters, and target speed are as follows: Real-time acquisition of the given current along the q-axis , give current The input is fed into a low-pass filter to obtain the first parameter. ; Real-time acquisition of q-axis feedback current , feedback current The input is fed into a low-pass filter to obtain the second parameter. ; Get the first parameter With the second parameter The difference E is used as the input of the PI controller to obtain the current feedback setpoint D1; According to the rated current and rated speed Calculate the amplification factor Kc of the feedforward term of the field weakening current; Obtain the current rotational speed increment of the field weakening, and adjust the rotational speed increment through the amplification factor Kc to obtain the current feedback setpoint D2; The d-axis current is obtained by adding the feedback reference D1 and the feedforward reference D2. .

7. The control method for a lifting AGV based on a permanent magnet motor according to claim 6, characterized in that, The formula for obtaining the current feedback reference term D1 is as follows: ； Where t is time, and These are the proportional gain coefficient and integral gain coefficient in the PI controller, respectively. The specific formula for obtaining the magnification factor Kc is as follows: ， in For rated current, Rated speed; The specific formula for obtaining the feedforward given term D2 is as follows: ;in, This is the rotational speed threshold.

8. The control method for a lifting AGV based on a permanent magnet motor according to claim 6, characterized in that, The formula for obtaining the q-axis current limit value is as follows: ； in For maximum output current, The current is along the d-axis.

9. A control system for a lifting AGV based on a permanent magnet motor, characterized in that, The control method for a lifting AGV based on a permanent magnet motor according to any one of claims 1 to 8 includes an image acquisition module, a determination module, a coefficient module, an adjustment module, and a control module; The image acquisition module is used to set up multiple image acquisition devices along the route traversed by the AGV. The image acquisition devices are used to acquire the orthographic projection image of the AGV when it is transporting goods. The determining module is used to obtain the midpoint of the goods in the orthographic projection image, and to obtain the vertical distance and horizontal distance between the midpoint of the pallet on the AGV and the midpoint of the goods. The coefficient module is used to obtain the weight of the goods and, based on the weight of the goods and the horizontal distance, obtain the adjustment coefficient of rotational inertia from a preset adjustment coefficient table. The initial moment of inertia of the cargo is obtained based on the vertical distance and the weight of the cargo. The initial moment of inertia is adjusted according to the adjustment coefficient of rotational inertia to obtain the final moment of inertia; The adjustment module is used to obtain the angular velocity V1 of the chassis motor, and calculate the angular velocity V2 of the pallet motor based on the angular velocity V1 and the final moment of inertia. The control module is used to select the corresponding d-axis current and q-axis current according to the magnitude of the angular velocity V2 of the pallet motor.

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