AGV control method based on driving wheel control

Abstract

The invention relates to the technical field of AGV control, and provides an AGV control method based on driving wheel control, and the method comprises the steps: an instruction receiving and transmitting module receives a control instruction, and generates an advancing path and an execution instruction; when the load-bearing lifting module is in a no-load state, the first motor drives the first driving wheel as a rear drive to run along the advancing path; a second motor outputs a corresponding forward motor target rotating speed to drive a second driving wheel as a front drive to execute steering action; when the third motor outputs a corresponding motor target rotating speed to drive the load-bearing lifting module to execute a lifting load action so as to enable the load-bearing lifting module to be in a load state, the first motor outputs a corresponding reverse motor target rotating speed to drive the first driving wheel to serve as a front drive to run along the advancing path and / or execute a steering action; and the second motor outputs the corresponding reverse motor target rotating speed to drive the second driving wheel to serve as a rear drive to run along the advancing path, and the efficiency and stability of the AGV facing load lifting and walking operation in the working process are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of AGV control, and in particular to an AGV control method based on driving wheel manipulation. Background Art

[0002] In automated logistics, warehousing and manufacturing, Automated Guided Vehicles (AGVs) are an important automated transportation tool and are widely used in scenarios such as material handling and assembly line automation. However, traditional AGV control methods often have problems such as low control accuracy and slow response speed when facing complex and changeable working conditions, such as load changes, steering control, and multi-mode operations (such as walking, turning, lifting, etc.). Therefore, it is particularly important to develop a control method that can efficiently, flexibly and accurately control AGVs.

[0003] Traditional control methods often use simple open-loop or closed-loop control strategies, but they are inadequate in handling load changes, multi-mode operation, and improving motor efficiency. For example, when the load changes, if the motor power distribution is unreasonable, it may cause the AGV to run unstably or even overturn; in steering control, if the motor drive method is not flexible enough, it may cause inaccurate steering or increased energy consumption; in multi-mode operation, if the motor control strategy is not smart enough, it may lead to slow response speed or waste of energy.

[0004] In summary, in order to overcome the shortcomings of traditional AGV control methods, this scheme proposes an AGV control method based on drive wheel control, which achieves efficient, flexible and precise control of AGV by optimizing the power distribution of the motor and the motor control strategy when the motor speed changes. Summary of the invention

[0005] In view of the above-mentioned defects, the purpose of the present invention is to propose an AGV control method based on drive wheel control, aiming to improve the efficiency and stability of the AGV when facing load lifting and walking operations during work, so as to make the AGV more reliable and flexible in practical applications.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] A control method for an AGV based on drive wheel control, the control method being applied to the AGV, the AGV comprising a pair of first drive wheels driven and controlled by a first motor, a pair of second drive wheels driven and controlled by a second motor, a load-bearing lifting module for carrying heavy objects driven and controlled by a third motor, and an instruction transceiver module for receiving control instructions and outputting execution instructions to the first motor, the second motor, and the third motor;

[0008] The control method comprises:

[0009] The instruction transceiver module receives the control instruction and generates a travel path, a first execution instruction, a second execution instruction and a third execution instruction according to the control instruction;

[0010] When the load-bearing lifting module is in an unloaded state:

[0011] The first motor outputs a corresponding forward motor target speed according to the first execution instruction to drive the first driving wheel as a rear drive to travel along the travel path;

[0012] The second motor outputs a corresponding forward motor target speed according to the second execution instruction to drive the second driving wheel as a front drive to perform a steering action;

[0013] When the third motor outputs a corresponding motor target speed according to the third execution instruction to drive the load-bearing lifting module to perform a load lifting action so that the load-bearing lifting module is in a load state:

[0014] The first motor outputs a corresponding reverse motor target speed according to the first execution instruction and the load weight to drive the first driving wheel as a front drive to travel along the travel path and / or perform a steering action;

[0015] The second motor outputs a corresponding reverse motor target speed according to the second execution instruction and the load weight to drive the second drive wheel as a rear drive along the travel path.

[0016] Preferably, when the load-bearing lifting module is in a loaded state, the second motor drives the second driving wheel as a rear drive to travel along the travel path, and the first motor drives the first driving wheel as a front drive to travel along the travel path but does not perform a turning action, the motor output energy obtained by the first driving wheel and the second driving wheel satisfies the relationship:

[0017] P 前 :P 后 =1:1;

[0018] Among them, P 前 represents the output energy of the first motor obtained by the first driving wheel, P 后 represents the output energy of the second motor obtained by the second driving wheel;

[0019] When the load-bearing lifting module is in a loaded state, the second motor drives the second driving wheel as a rear drive to travel along the travel path, and the first motor drives the first driving wheel as a front drive to travel along the travel path and perform a turning action, the motor output energy obtained by the first driving wheel and the second driving wheel satisfies the relationship:

[0020] P 前 :P 后 =1+kθ:1-kθ;

[0021] Where θ represents the steering angle of the first driving wheel, k represents the proportional constant of the steering angle to the power distribution determined by the AGV itself, r represents the power distribution ratio between the first driving wheel and the second driving wheel, P 前 represents the output energy of the first motor obtained by the first driving wheel, P 后 Represents the output energy of the second motor obtained by the second driving wheel.

[0022] Furthermore, when the load-bearing lifting module has no load, the output energy of the first motor and the speed of the first driving wheel and when the load-bearing lifting module is in a loaded state, the output energy of the second motor and the speed of the second driving wheel satisfy the relationship:

[0023]

[0024] Where T is the driving torque on the driving wheel, v 轮 represents the speed of the driving wheel, r represents the radius of the driving wheel, P 出 Indicates the output energy of the first motor or the second motor.

[0025] Preferably, when the third motor outputs a corresponding motor target speed according to the third execution instruction to drive the load-bearing lifting module to perform a uniform load lifting action, the motor output energy obtained by the load-bearing lifting module satisfies the relationship:

[0026] P 升 =ΔL·v 升 ;

[0027] Among them, P 升 is the output energy of the third motor obtained by the load-bearing lifting module, ΔL represents the load change of the load-bearing lifting module, v 升 Indicates the speed at which the load-bearing lifting module is lifted;

[0028] When the third motor outputs the corresponding motor target speed according to the third execution instruction to drive the load-bearing lifting module to perform acceleration or deceleration load lifting action, the motor output energy obtained or lost by the load-bearing lifting module satisfies the relationship:

[0029] P 升 =ΔL(g+a)·v 升 ;

[0030] Among them, P 升 is the output energy of the third motor obtained by the load-bearing lifting module, ΔL represents the load change of the load-bearing lifting module, g represents the gravity acceleration, a represents the acceleration when the load-bearing lifting module accelerates or decelerates, and v 升 Indicates the speed at which the load-bearing lifting module is raised or lowered.

[0031] Preferably, when the load-bearing lifting module is in an unloaded state:

[0032] Adjust the output energy of the first motor according to the speed of the first driving wheel in the first execution instruction and then adjust the target speed of the first motor;

[0033] adjusting the output energy of the second motor and thus adjusting the target speed of the second motor according to the steering amplitude and steering angular velocity of the second driving wheel in the second execution instruction;

[0034] When the load-bearing lifting module is in a loaded state:

[0035] According to the load variation and the speed of the second driving wheel in the second execution instruction, the output energy of the second motor is adjusted to thereby adjust the target speed of the second motor;

[0036] According to the load variation and the speed, steering amplitude and steering angular velocity of the first driving wheel in the first execution instruction, the output energy of the first motor is adjusted to thereby adjust the target speed of the first motor;

[0037] The output energy of the third motor is adjusted according to the load change and the lifting speed of the load-bearing lifting module in the third execution instruction, thereby adjusting the target speed of the third motor.

[0038] Furthermore, in adjusting the output energy of the motor and thus adjusting the target speed of the motor, the output energy of the motor and the target speed of the motor satisfy the relationship:

[0039]

[0040] Where T is the torque generated by the motor, P 出 It represents the output energy of the motor, and RPM represents the target speed of the motor per minute.

[0041] Further, when adjusting the target speeds of the first motor, the second motor and the third motor, it is determined whether the target speeds of the motors are lower than the preset motor turning speeds. If so, the MTPA current control method is used to generate corresponding d-axis and q-axis currents;

[0042] The d-axis current and the q-axis current are input into the controller to obtain the d-axis and q-axis voltages, and the motor is driven to operate according to the d-axis and q-axis voltages.

[0043] Further, when the target speeds of the first motor, the second motor and the third motor are adjusted, it is determined whether the target speeds of the motors are higher than the preset motor turning speeds. If so, the current of the d-axis is obtained according to the operating parameters, design parameters and target speeds of the motors, and the limit value of the q-axis current is obtained according to the maximum current and the current of the d-axis.

[0044] The d-axis current and the q-axis current are input into the controller to obtain the d-axis and q-axis voltages, and the motor is driven to operate according to the d-axis and q-axis voltages.

[0045] Furthermore, the operating parameters include: a given current of the q-axis, a feedback current of the q-axis;

[0046] The design parameters include: rated current of the motor and rated speed of the motor.

[0047] Furthermore, the step of obtaining the current of the d-axis is as follows:

[0048] Get the given current I of the q axis in real time qRef , the given current I qRef Input to the low-pass filter to get the first parameter I q ' Ref ;

[0049] Get the feedback current I of the q axis in real time q , the given current I q Input to the low-pass filter to obtain the second parameter I q ′;

[0050] Get the first parameter I q ' Ref With the second parameter I q The difference E of ′ is used as the input of the PI controller to obtain the current feedback given term D1;

[0051] According to the rated current I n and rated speed ω n Calculate the amplification factor Kc of the current feedforward given term;

[0052] Obtain the current speed increment, adjust the speed increment by the amplification factor Kc, and obtain the current feedback given item D2;

[0053] The d-axis current I is obtained by adding the feedback given term D1 and the feedforward given term D2. d .

[0054] One of the above technical solutions has the following advantages or beneficial effects:

[0055] When the load-bearing lifting module is in a loaded state, the first motor and the second motor adjust the motor target speed according to the load weight to compensate for the impact of the load on driving and steering, which can ensure the stability of the AGV under different load conditions and reduce the speed change and steering error caused by the load. The AGV can still maintain efficient and stable operating performance under loaded conditions, improving the safety and reliability during transportation. In the unloaded state, the positive target speed of the first motor and the second motor drives the AGV to achieve normal travel and steering movements, ensuring the flexibility of the AGV in the unloaded state, and can accurately travel along the travel path and smoothly perform steering movements. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0057] Figure 1 is a schematic diagram of an AGV control method based on drive wheel control provided by an embodiment of the present invention;

[0058] Figure 2 It is a simplified diagram of an AGV according to an AGV control method based on drive wheel control provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0059] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0060] In this application, the terms "comprises", "comprising" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0061] like Figure 1As shown, a preferred embodiment of the present application is an AGV control method based on drive wheel control, the control method is applied to the AGV, the AGV includes a pair of first drive wheels driven and controlled by a first motor, a pair of second drive wheels driven and controlled by a second motor, a load-bearing lifting module for carrying heavy objects driven and controlled by a third motor, and an instruction transceiver module for receiving control instructions and outputting execution instructions to the first motor, the second motor and the third motor;

[0062] The control method comprises the steps of:

[0063] S1: The instruction transceiver module receives a control instruction, and generates a travel path, a first execution instruction, a second execution instruction, and a third execution instruction according to the control instruction;

[0064] When the load-bearing lifting module is in an unloaded state:

[0065] S21: the first motor outputs a corresponding forward motor target speed according to the first execution instruction to drive the first driving wheel to travel along the travel path as a rear-wheel drive;

[0066] S22: the second motor outputs a corresponding forward motor target speed according to the second execution instruction to drive the second driving wheel as a front drive to perform a steering action;

[0067] S31: When the third motor outputs a corresponding motor target speed according to the third execution instruction to drive the load-bearing lifting module to perform a load lifting action so that the load-bearing lifting module is in a load state:

[0068] S32: the first motor outputs a corresponding reverse motor target speed according to the first execution instruction and the load weight to drive the first driving wheel as a front drive to travel along the travel path and / or perform a steering action;

[0069] S33: The second motor outputs a corresponding reverse motor target speed according to the second execution instruction and the load weight to drive the second drive wheel as a rear drive along the travel path.

[0070] Specifically, in this embodiment, in order to further better illustrate the technical principle of this method, the following is provided: Figure 2 The schematic diagram corresponding to the existing structure of the AGV based on drive wheel control is shown, with a first motor ( Figure 2 A pair of first driving wheels ( Figure 2 100), the second motor ( Figure 2 A pair of second driving wheels ( Figure 2 300 in the figure), the third motor ( Figure 2The load-bearing lifting module ( Figure 2 200), and an instruction transceiver module ( Figure 2 not shown).

[0071] In step S1, the instruction transceiver module receives control instructions from the user or the system, and generates corresponding travel paths and execution instructions. The travel path is the movement route that the AGV needs to follow. The control instructions generate the first execution instruction, the second execution instruction and the third execution instruction, which respectively instruct the first motor, the second motor and the third motor to perform corresponding actions.

[0072] When the load-bearing lifting module is unloaded, that is, when the AGV is unloaded, steps S21 and S22 are executed:

[0073] In step S21, the AGV goes to the target location according to the travel path to carry the goods. During the travel, the first drive wheel is the rear drive wheel used to propel the AGV forward. While controlling the first drive wheel, the first motor adjusts the target speed of the motor so that the first drive wheel can obtain sufficient power to complete the first execution instruction. The forward direction mentioned here indicates the direction. Assuming that the direction of the AGV going to the destination to obtain the goods is the forward direction, then the direction of the AGV transporting the goods back to the starting point is the reverse direction.

[0074] In step S22, the second drive wheel is a front drive wheel used to change the traveling direction of the AGV. While controlling the second drive wheel, the second motor adjusts the target speed of the motor so that the second drive wheel can obtain sufficient power to complete the turning.

[0075] For example, after obtaining the goods, the goods are placed on the load-bearing lifting module. In order to facilitate transportation, the load-bearing lifting module is used to lift the goods. Therefore, when there is a load on the load-bearing lifting module, steps S31, S32 and S33 are executed:

[0076] In step S31, in order to enable the load-bearing lifting module to smoothly execute the third execution instruction, the third motor adjusts its own rotation speed to increase the output power to cope with different load weight changes and lifting requirements.

[0077] In step S32, on the return journey, the first drive wheel is converted to the front drive wheel. Due to the increase in load, the front drive wheel not only needs to realize the steering function, but also needs to push the AGV forward. Therefore, the first motor adjusts the target speed of the motor to increase the output, so that the first drive wheel can smoothly execute the first execution instruction and overcome the load weight.

[0078] In step S33, similar to step S32, the second motor outputs the corresponding reverse motor target speed, converting the second drive wheel into a rear drive wheel to achieve the function of pushing the AGV forward.

[0079] When the load-bearing lifting module is in a loaded state, the first motor and the second motor adjust the motor target speed according to the load weight to compensate for the impact of the load on driving and turning, which can ensure the stability of the AGV under different load conditions, reduce the speed change and steering error caused by the load, and the AGV can still maintain efficient and stable operating performance under the loaded state, improving the safety and reliability during transportation. In the unloaded state, the positive target speed of the first motor and the second motor drives the AGV to achieve normal travel and turning movements, ensuring the flexibility of the AGV in the unloaded state, enabling it to accurately travel along the travel path and smoothly perform turning movements, which is particularly important in narrow or complex environments, and improves the adaptability of the AGV under various operating conditions. The control of the third motor enables the load-bearing lifting module to accurately perform lifting actions, ensuring that the AGV can move stably when carrying heavy objects, avoiding interference with the driving stability of the AGV during the load lifting process, and improving the operating efficiency of the equipment, especially in scenarios that require frequent lifting operations.

[0080] Preferably, when the load-bearing lifting module is in a loaded state, the second motor drives the second driving wheel as a rear drive to travel along the travel path, and the first motor drives the first driving wheel as a front drive to travel along the travel path but does not perform a turning action, the motor output energy obtained by the first driving wheel and the second driving wheel satisfies the relationship:

[0081] P 前 :P 后 =1:1;

[0082] Among them, P 前 represents the output energy of the first motor obtained by the first driving wheel, P 后 represents the output energy of the second motor obtained by the second driving wheel;

[0083] When the load-bearing lifting module is in a loaded state, the second motor drives the second driving wheel as a rear drive to travel along the travel path, and the first motor drives the first driving wheel as a front drive to travel along the travel path and perform a turning action, the motor output energy obtained by the first driving wheel and the second driving wheel satisfies the relationship:

[0084] P 前 :P 后 =1+kθ:1-kθ;

[0085] Where θ represents the steering angle of the first driving wheel, k represents the proportional constant of the steering angle to the power distribution determined by the AGV itself, r represents the power distribution ratio between the first driving wheel and the second driving wheel, P 前 represents the output energy of the first motor obtained by the first driving wheel, P 后 Represents the output energy of the second motor obtained by the second driving wheel.

[0086] Specifically, when the AGV is loaded and does not need to turn, the corresponding motor output energies obtained by the first drive wheel and the second drive wheel are the same, and the equal energy distribution ensures the stability of the AGV when driving in a straight line.

[0087] When steering is required, the energy distribution between the first drive wheel and the second drive wheel changes, and the dynamic energy distribution adapts to the load change during steering, improving the handling performance and steering accuracy of the AGV. For example, when steering, the load of the load-bearing lifting module is 500kg, the steering angle of the first drive wheel is 15°, and the proportional constant k of the steering angle to the power distribution is 0.2, then P 前 :P 后 =1.86:1, so the energy required by the first drive wheel is greater than that required by the second drive wheel, and the corresponding motor needs to allocate more energy to stably control the AGV to travel along the travel path.

[0088] Furthermore, when the load-bearing lifting module has no load, the output energy of the first motor and the speed of the first driving wheel and when the load-bearing lifting module is in a loaded state, the output energy of the second motor and the speed of the second driving wheel satisfy the relationship:

[0089]

[0090] Where T represents the driving torque on the driving wheel, v represents the speed of the driving wheel, r represents the radius of the driving wheel, and P 出 Indicates the output energy of the first motor or the second motor.

[0091] Specifically, when the load-bearing lifting module has no load, the first drive wheel acts as the rear drive wheel, which only needs to push the AGV forward without controlling the steering. When the load-bearing lifting module is in a loaded state, the second drive wheel acts as the rear drive wheel, which also only needs to push the AGV forward without controlling the steering. The relationship between the output energy of all motors and the speed of the drive wheels satisfies Assume that the driving torque T of the driving wheel is 60Nm and the speed v of the driving wheel is 轮 is 2m / s, the radius r of the driving wheel is 0.3m, and the output energy P of the first motor or the second motor is obtained from the above formula 出 It is 400W.

[0092] Preferably, when the third motor outputs a corresponding motor target speed according to the third execution instruction to drive the load-bearing lifting module to perform a uniform load lifting action, the motor output energy obtained by the load-bearing lifting module satisfies the relationship:

[0093] P 升 =ΔL·v 升 ;

[0094] Among them, P升 is the output energy of the third motor obtained by the load-bearing lifting module, ΔL represents the load change of the load-bearing lifting module, v 升 Indicates the speed at which the load-bearing lifting module is lifted;

[0095] When the third motor outputs the corresponding motor target speed according to the third execution instruction to drive the load-bearing lifting module to perform acceleration or deceleration load lifting action, the motor output energy obtained or lost by the load-bearing lifting module satisfies the relationship:

[0096] P 升 =ΔL(g+a)·v 升 ;

[0097] Among them, P 升 is the output energy of the third motor obtained by the load-bearing lifting module, ΔL represents the load change of the load-bearing lifting module, g represents the gravity acceleration, a represents the acceleration when the load-bearing lifting module accelerates or decelerates, and v 升 Indicates the speed at which the load-bearing lifting module is raised or lowered.

[0098] Specifically, assuming the load change is 100 kg and the lifting speed v 升 =2m / s, the acceleration due to gravity is 9.8m / s 2 , the acceleration of acceleration or deceleration is a = 1m / s 2 ,Under the condition of uniform speed, the energy required by the load-bearing lifting module is 200W. The third motor needs to adjust the corresponding target speed to output enough energy to the load-bearing lifting module to realize the lifting action.

[0099] In the process of acceleration or deceleration, taking acceleration as an example, according to the relationship P 升 =ΔL(g+a)·v 升 , the output energy of the third motor needs to reach 2160W to achieve the purpose of accelerated ascent. Similarly, the acceleration is vertically downward during deceleration and ascent, so the value of a can be positive or negative. The energy calculation takes into account the combined effects of gravity acceleration and acceleration, ensuring that the motor can provide appropriate energy under load, acceleration and deceleration, to meet the needs of load lifting.

[0100] Preferably, when the load-bearing lifting module is in an unloaded state:

[0101] Adjust the output energy of the first motor according to the speed of the first driving wheel in the first execution instruction and then adjust the target speed of the first motor;

[0102] adjusting the output energy of the second motor and thus adjusting the target speed of the second motor according to the steering amplitude and steering angular velocity of the second driving wheel in the second execution instruction;

[0103] When the load-bearing lifting module is in a loaded state:

[0104] According to the load variation and the speed of the second driving wheel in the second execution instruction, the output energy of the second motor is adjusted to thereby adjust the target speed of the second motor;

[0105] According to the load variation and the speed, steering amplitude and steering angular velocity of the first driving wheel in the first execution instruction, the output energy of the first motor is adjusted to thereby adjust the target speed of the first motor;

[0106] The output energy of the third motor is adjusted according to the load change and the lifting speed of the load-bearing lifting module in the third execution instruction, thereby adjusting the target speed of the third motor.

[0107] Specifically, in the no-load state, the first drive wheel is the rear-drive wheel, and the first drive wheel only propels the AGV forward under load, so the target speed of the first motor is directly related to the speed setting of the first drive wheel. The higher the speed means the more energy required by the first drive wheel, and the higher the target speed of the first motor needs to be. The second drive wheel is the front-drive wheel, and the second drive wheel only needs to realize the steering of the AGV, so the target speed of the second motor is directly related to the steering amplitude and steering angular velocity settings of the second drive wheel. The larger the steering amplitude and the steering angular velocity, the greater the target speed of the motor.

[0108] Under load, the first drive wheel needs to push the AGV forward and realize the AGV steering. Therefore, when the load increases, the force required to push the AGV forward increases, which requires the rear drive wheel to provide more torque. Therefore, the target speed of the first motor needs to increase to adapt to the increase in load. The larger the load, the higher the target speed of the first motor to provide sufficient power to overcome the additional resistance. The target speed of the first motor is related to the speed setting of the first drive wheel. When the speed is higher, the motor needs to provide a higher speed to maintain the speed. The steering operation requires more power to maintain stability and direction control, so the speed of the motor will also be affected to a certain extent. The second drive wheel realizes the advancement of the AGV. The higher the speed of the second drive wheel, the greater the load, and the faster the speed required by the second motor. When the load of the load-bearing lifting module increases, more motor output energy is required to complete the lifting operation. The target speed of the third motor needs to be adjusted accordingly according to the load change to ensure that the lifting module can work normally under load. The target speed of the lifting module is related to the lifting speed. Under load, the lifting speed needs to be adjusted to ensure that the load can be lifted and lowered stably. Therefore, the target speed of the third motor also needs to be adjusted to match the change in the lifting speed.

[0109] In adjusting the output energy of the motor and thus adjusting the target speed of the motor, the output energy of the motor and the target speed of the motor satisfy the relationship:

[0110]

[0111] Where T is the torque generated by the motor, P 出 It represents the output energy of the motor, and RPM represents the target speed of the motor per minute.

[0112] Specifically, when adjusting the target speed of the motor, it is necessary to convert it according to the output energy of the motor. Assuming that the output energy P of the motor is 出 The power is 500W, and the torque T generated by the motor is 1.5N·M. Substituting this into the above formula, the target speed of the motor is 3183RPM.

[0113] Further, when adjusting the target speeds of the first motor, the second motor and the third motor, it is determined whether the target speeds of the motors are lower than the preset motor turning speeds. If so, the MTPA current control method is used to generate corresponding d-axis and q-axis currents;

[0114] The d-axis current and the q-axis current are input into the controller to obtain the d-axis and q-axis voltages, and the motor is driven to operate according to the d-axis and q-axis voltages.

[0115] Specifically, in order to use the minimum current to generate the maximum motor speed, the MTPA current control method is adopted, in which the output current I is divided into the current I output to the d-axis d And the current I output to the q axis q , where the current I q The main control is the current in the torque direction, where the current I d The main control is the current in the direction of the magnetic field. This embodiment is mainly to weaken the motor magnetic field and reduce the back electromotive force when the power input voltage is limited, so as to achieve the purpose of increasing the motor speed. For this reason, in the present invention, it is first determined whether the current speed is lower than the turning speed. Because when the current speed is lower than the turning speed, it means that the motor is still running in the constant torque area, and there is no need to reduce the motor back electromotive force or increase the speed by weakening the magnetic flux. At this time, the MTPA method is used to reduce the current I d Set it to 0 and then calculate the minimum current I q To generate as much torque as possible, so that the motor can quickly increase the speed, so that the current speed rises rapidly, because in I d = 0, the motor's d-axis current is always zero, reducing the electromagnetic interference and vibration caused by the change of d-axis current, which helps to maintain the stable operation of the motor. q ,I d Inverse PARK transformation is performed to generate Ua and Ub control signals, which are then sent to the SVPWM module to generate drive signals to control the motor.

[0116] In another embodiment, when the target speeds of the first motor, the second motor, and the third motor are adjusted, it is determined whether the target speeds of the motors are higher than the preset motor turning speeds. If so, the current of the d-axis is obtained according to the operating parameters, design parameters, and target speeds of the motors, and the limit value of the q-axis current is obtained according to the maximum current and the current of the d-axis.

[0117] The d-axis current and the q-axis current are input into the controller to obtain the d-axis and q-axis voltages, and the motor is driven to operate according to the d-axis and q-axis voltages.

[0118] Specifically, when the target speed of the motor is higher than the preset motor turning speed, the output of the motor will increase, resulting in an increase in the magnetic flux level inside the motor, and the motor will consume more energy to maintain the magnetic field. Therefore, in order to reduce the magnetic flux, when the target speed of the motor is higher than the preset motor turning speed, the d-axis current is controlled and the q-axis current is limited based on the operating parameters and design parameters, which can speed up the achievement of the target stride and step frequency requirements. At the same time, the q-axis current is limited. If the q-axis current I d If the current command is too high, the motor may generate large torque fluctuations during dynamic response, affecting the stable operation of the motor. By limiting the q-axis current command, the torque fluctuation can be reduced and the stability of the motor can be enhanced. q ,I d Inverse PARK transformation is performed to generate Ua and Ub control signals, which are then sent to the SVPWM module to generate drive signals to control the motor.

[0119] Preferably, the operating parameters include: a given current of the q-axis, a feedback current of the q-axis;

[0120] The design parameters include: rated current of the motor and rated speed of the motor.

[0121] The steps of obtaining the current of the d-axis are as follows:

[0122] Get the given current I of the q axis in real time qRef , the given current I qRef Input to the low-pass filter to get the first parameter I q ' Ref ;

[0123] Get the feedback current I of the q axis in real time q , the given current I q Input to the low-pass filter to obtain the second parameter I q ′;

[0124] Get the first parameter I q ' Ref With the second parameter I qThe difference E of ′ is used as the input of the PI controller to obtain the current feedback given term D1;

[0125] According to the rated current I n and rated speed ω n Calculate the amplification factor Kc of the current feedforward given term;

[0126] Obtain the current speed increment, adjust the speed increment by the amplification factor Kc, and obtain the current feedback given item D2;

[0127] The d-axis current I is obtained by adding the feedback given term D1 and the feedforward given term D2. d .

[0128] Specifically, when the motor controls the driving wheel, by obtaining the given current and feedback current of the q-axis in real time 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 and improve stability and reliability. By calculating the difference E between the given current and the feedback current and using 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. The determination of the calculated amplification factor Kc is based on the rated current and rated speed of the motor. The speed increment is adjusted by the amplification factor Kc, which can ensure that the motor runs in an efficient and stable state. In the present invention, feedback control and feedforward control are combined, and the current of the d-axis is obtained by a simple addition operation. The d-axis current can also be accurately obtained without relying on a complex algorithm, and the feedforward given item D1 of the current can improve the speed response of the motor speed during rapid switching, and the feedback given item of the current ensures the speed stability of the motor under heavy load conditions. The method has a small amount of calculation, a simple structure, and high operating stability.

[0129] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0130] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. An AGV control method based on drive wheel control, the control method is applied to the AGV, the AGV comprises a pair of first drive wheels driven and controlled by a first motor, a pair of second drive wheels driven and controlled by a second motor, a load-bearing lifting module for carrying heavy objects driven and controlled by a third motor, and an instruction transceiver module for receiving control instructions and outputting execution instructions to the first motor, the second motor and the third motor; It is characterized in that The control method comprises: The instruction transceiver module receives the control instruction and generates a travel path, a first execution instruction, a second execution instruction and a third execution instruction according to the control instruction; When the load-bearing lifting module is in an unloaded state: The first motor outputs a corresponding forward motor target speed according to the first execution instruction to drive the first driving wheel as a rear drive to travel along the travel path; The second motor outputs a corresponding forward motor target speed according to the second execution instruction to drive the second driving wheel as a front drive to perform a steering action; When the third motor outputs a corresponding motor target speed according to the third execution instruction to drive the load-bearing lifting module to perform a load lifting action so that the load-bearing lifting module is in a load state: The first motor outputs a corresponding reverse motor target speed according to the first execution instruction and the load weight to drive the first driving wheel as a front drive to travel along the travel path and / or perform a steering action; The second motor outputs a corresponding reverse motor target speed according to the second execution instruction and the load weight to drive the second drive wheel as a rear drive along the travel path.

2. The control method according to claim 1, characterized in that: When the load-bearing lifting module is in a loaded state, the second motor drives the second driving wheel as a rear drive to travel along the travel path, and the first motor drives the first driving wheel as a front drive to travel along the travel path but does not perform a steering action, the motor output energy obtained by the first driving wheel and the second driving wheel satisfies the relationship: P 前 :P 后 =1:1; Among them, P 前 represents the output energy of the first motor obtained by the first driving wheel, P 后 represents the output energy of the second motor obtained by the second driving wheel; When the load-bearing lifting module is in a loaded state, the second motor drives the second driving wheel as a rear drive to travel along the travel path, and the first motor drives the first driving wheel as a front drive to travel along the travel path and perform a turning action, the motor output energy obtained by the first driving wheel and the second driving wheel satisfies the relationship: P 前 :P 后 =1+kθ:1-kθ; Where θ represents the steering angle of the first driving wheel, k represents the proportional constant of the steering angle to the power distribution determined by the AGV itself, r represents the power distribution ratio between the first driving wheel and the second driving wheel, P 前 represents the output energy of the first motor obtained by the first driving wheel, P 后 Represents the output energy of the second motor obtained by the second driving wheel.

3. The control method according to claim 2, characterized in that: When the load-bearing lifting module is unloaded, the output energy of the first motor and the speed of the first driving wheel and when the load-bearing lifting module is in a loaded state, the output energy of the second motor and the speed of the second driving wheel satisfy the relationship: Where T is the driving torque on the driving wheel, v 轮 represents the speed of the driving wheel, r represents the radius of the driving wheel, P 出 Indicates the output energy of the first motor or the second motor.

4. The control method according to claim 1, characterized in that: When the third motor outputs a corresponding motor target speed according to the third execution instruction to drive the load-bearing lifting module to perform a uniform load lifting action, the motor output energy obtained by the load-bearing lifting module satisfies the relationship: P 升 =ΔL·v 升 ; Among them, P 升 is the output energy of the third motor obtained by the load-bearing lifting module, ΔL represents the load change of the load-bearing lifting module, v 升 Indicates the speed at which the load-bearing lifting module is lifted; When the third motor outputs the corresponding motor target speed according to the third execution instruction to drive the load-bearing lifting module to perform acceleration or deceleration load lifting action, the motor output energy obtained or lost by the load-bearing lifting module satisfies the relationship: P 升 =ΔL(g+a)·v 升 ; Among them, P 升 is the output energy of the third motor obtained by the load-bearing lifting module, ΔL represents the load change of the load-bearing lifting module, g represents the gravity acceleration, a represents the acceleration when the load-bearing lifting module accelerates or decelerates, and v 升 Indicates the speed at which the load-bearing lifting module is raised or lowered.

5. The control method according to claim 1, characterized in that: When the load-bearing lifting module is in an unloaded state: Adjust the output energy of the first motor according to the speed of the first driving wheel in the first execution instruction and then adjust the target speed of the first motor; adjusting the output energy of the second motor and thus adjusting the target speed of the second motor according to the steering amplitude and steering angular velocity of the second driving wheel in the second execution instruction; When the load-bearing lifting module is in a loaded state: According to the load variation and the speed of the second driving wheel in the second execution instruction, the output energy of the second motor is adjusted to thereby adjust the target speed of the second motor; According to the load variation and the speed, steering amplitude and steering angular velocity of the first driving wheel in the first execution instruction, the output energy of the first motor is adjusted to thereby adjust the target speed of the first motor; The output energy of the third motor is adjusted according to the load change and the lifting speed of the load-bearing lifting module in the third execution instruction, thereby adjusting the target speed of the third motor.

6. The control method according to claim 5, characterized in that: In adjusting the output energy of the motor and thus adjusting the target speed of the motor, the output energy of the motor and the target speed of the motor satisfy the relationship: Where T is the torque generated by the motor, P 出 It represents the output energy of the motor, and RPM represents the target speed of the motor per minute.

7. The control method according to claim 6, characterized in that: When adjusting the target speeds of the first motor, the second motor and the third motor, it is determined whether the target speeds of the motors are lower than the preset motor turning speeds. If so, the MTPA current control method is used to generate corresponding d-axis and q-axis currents. The d-axis current and the q-axis current are input into the controller to obtain the d-axis and q-axis voltages, and the motor is driven to operate according to the d-axis and q-axis voltages.

8. The control method according to claim 7, characterized in that: When adjusting the target speeds of the first motor, the second motor and the third motor, it is determined whether the target speeds of the motors are higher than the preset motor turning speeds. If so, the current of the d-axis is obtained according to the operating parameters, design parameters and target speeds of the motors, and the limit value of the q-axis current is obtained according to the maximum current and the current of the d-axis. The d-axis current and the q-axis current are input into the controller to obtain the d-axis and q-axis voltages, and the motor is driven to operate according to the d-axis and q-axis voltages.

9. The control method according to claim 8, characterized in that: The operating parameters include: given current of q axis, feedback current of q axis; The design parameters include: rated current of the motor and rated speed of the motor.

10. The control method according to claim 9, characterized in that: The steps of obtaining the current of the d-axis are as follows: Get the given current I of the q axis in real time qRef , the given current I qRef Input to the low-pass filter to get the first parameter I' qRef ; Get the feedback current I of the q axis in real time q , the given current I q Input to the low-pass filter to obtain the second parameter I' q ; Get the first parameter I' qRef and the second parameter I′ q The difference E is used as the input of the PI controller to obtain the current feedback given term D1; According to the rated current I n and rated speed ω n Calculate the amplification factor Kc of the current feedforward given term; Obtain the current speed increment, adjust the speed increment by the amplification factor Kc, and obtain the current feedback given item D2; The d-axis current I is obtained by adding the feedback given term D1 and the feedforward given term D2. d .

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