AGV control method based on driving wheel steering

Abstract

The present application relates to the technical field of AGV control, and proposes an AGV control method based on driving wheel operation, which comprises: an instruction transceiver module receives a control instruction, generates a travel path and an execution instruction; when a load lifting module is in an empty state: a first motor drives a first driving wheel as a rear drive to travel along the travel path; a second motor outputs a corresponding forward motor target speed to drive a second driving wheel as a front drive to perform a steering action; a third motor outputs a corresponding motor target speed to drive the load lifting module to perform a load lifting action so that the load lifting module is in a load state: the first motor outputs a corresponding reverse motor target speed 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 to drive the second driving wheel as a rear drive to travel along the travel path, thereby improving the efficiency and stability of the AGV when facing load lifting and walking operations during work.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of AGV control, and particularly relates to an AGV control method based on driving wheel control. BACKGROUND

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

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

[0004] In summary, in order to overcome the deficiencies of the traditional AGV control method, the present application proposes an AGV control method based on driving wheel control, which optimizes the power distribution of the motor and the motor control strategy when the motor speed changes, to achieve efficient, flexible and accurate control of AGV. SUMMARY

[0005] In view of the above defects, the present application aims to provide an AGV control method based on driving wheel control, which aims to improve the efficiency and stability of AGV when facing load lifting and walking operations during work, so that AGV is more reliable and flexible in actual application.

[0006] To achieve this purpose, the present application adopts the following technical solutions:

[0007] An AGV control method based on driving wheel control, the control method is applied to the AGV, the AGV includes a pair of first driving wheels driven and controlled by a first motor, a pair of second driving wheels driven and controlled by a second motor, a load lifting module for lifting 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 control instructions and generates a travel path, a first execution instruction, a second execution instruction, and a third execution instruction based on the control instructions.

[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 command to drive the first drive wheel as the rear drive to travel along the travel path;

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

[0013] The third motor outputs a target motor speed according to the third execution command to drive the load-bearing lifting module to perform lifting and lowering operations 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 command and the load weight to drive the first drive wheel as the front drive to travel along the travel path and / or perform steering actions;

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

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

[0017] P 前 :P 后 =1:1;

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

[0019] When the load-bearing lifting module is under load, the second motor drives the second drive wheel as the rear drive to travel along the path, and the first motor drives the first drive wheel as the front drive to travel along the path and perform a steering action. The motor output energy obtained by the first drive wheel and the second drive wheel satisfies the following relationship:

[0020] P 前 :P 后 =1+kθ:1-kθ;

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

[0022] Further, the output energy of the first motor and the speed of the first driving wheel when the load-bearing lifting module is not under load, and the output energy of the second motor and the speed of the second driving wheel when the load-bearing lifting module is under load, satisfy the relationship:

[0023]

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

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

[0026] P 升 = ΔL·v 升 ;

[0027] wherein P 升 is the third motor output energy obtained by the load-bearing lifting module, ΔL represents a load change amount of the load-bearing lifting module, v 升 represents a speed of lifting of the load-bearing lifting module;

[0028] When the third motor drives the load-bearing lifting module to perform an acceleration or deceleration lifting load action according to the third execution instruction outputting a corresponding motor target speed, 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] wherein P 升 is the third motor output energy obtained by the load-bearing lifting module, ΔL represents a load change amount of the load-bearing lifting module, g represents a gravitational acceleration, a represents an acceleration when the load-bearing lifting module accelerates or decelerates, v 升 represents a speed of lifting of the load-bearing lifting module.

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

[0032] The output energy of the first motor is adjusted according to the speed of the first driving wheel in the first execution instruction, so as to adjust the target rotating speed of the first motor;

[0033] The output energy of the second motor is adjusted according to the steering amplitude and the steering angular speed of the second driving wheel in the second execution instruction, so as to adjust the target rotating speed of the second motor;

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

[0035] The output energy of the second motor is adjusted according to the load change amount and the speed of the second driving wheel in the second execution instruction, so as to adjust the target rotating speed of the second motor;

[0036] The output energy of the first motor is adjusted according to the load change amount and the speed, the steering amplitude and the steering angular speed of the first driving wheel in the first execution instruction, so as to adjust the target rotating speed of the first motor;

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

[0038] Further, in the adjustment of the output energy of the motor and the target rotating speed of the motor, the output energy of the motor and the target rotating speed of the motor satisfy the relationship:

[0039]

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

[0041] Further, when the target rotating speed of the first motor, the second motor and the third motor is adjusted, it is judged whether the target rotating speed of the motor is lower than a preset motor turning rotating speed, if yes, the current of the d-axis and the q-axis is generated by using the current control mode of MTPA;

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

[0043] Further, when the target rotating speed of the first motor, the second motor and the third motor is adjusted, it is judged whether the target rotating speed of the motor is higher than a preset motor turning rotating speed, if yes, the current of the d-axis is obtained according to the operating parameter, the design parameter and the target rotating speed of the motor, and the limiting 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 voltage and the q-axis voltage, and the motor is driven to operate according to the d-axis voltage and the q-axis voltage.

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

[0046] The design parameters include: a rated current of the motor, a rated rotating speed of the motor.

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

[0048] The given current I qRef of the q-axis is obtained in real time. qRef The given current I q ′ is input into a low-pass filter to obtain a first parameter I Ref .

[0049] The feedback current I q of the q-axis is obtained in real time. q The feedback current I q ′ is input into a low-pass filter to obtain a second parameter I q .

[0050] The difference E between the first parameter I Ref ′ and the second parameter I q ′ is obtained, and the difference E is taken as an input of a PI controller to obtain a current feedback given item D1.

[0051] The rated current I n and the rated rotating speed ω n are used to calculate an amplification coefficient Kc of a current feedforward given item.

[0052] The current rotating speed increment is obtained, and the rotating speed increment is adjusted by the amplification coefficient Kc to obtain a current feedback given item D2.

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

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

[0055] When the load-bearing lifting module is in a load state, the first motor and the second motor adjust the motor target rotating speed according to the load weight to compensate for the influence of the load on driving and steering, so as to ensure the stability of the AGV under different load conditions, reduce the speed change and steering error caused by the load, and ensure the high efficiency and stability of the AGV under the load state, thereby improving the safety and reliability in the transportation process. In the empty state, the forward target rotating speed of the first motor and the second motor drives the AGV to realize normal driving and steering actions, so as to ensure the flexibility of the AGV in the empty state, and the AGV can accurately drive along the driving path and smoothly perform the steering action. BRIEF DESCRIPTION OF DRAWINGS

[0056] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only constitute the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of the provided drawings.

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

[0058] Figure 2 is a brief diagram of the AGV based on the AGV control method based on driving wheel control provided by the embodiment of the present application. DETAILED DESCRIPTION

[0059] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0060] In the present application, the term "comprising", "containing" or any other variant thereof is intended to cover non-exclusive containing, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment. Without more limitation, the element defined by the sentence "including a…" does not exclude the presence of other identical elements in the process, method, article or equipment including the element.

[0061] As Figure 1As shown, one preferred embodiment of the present application is a driving wheel control based AGV control method, which is applied to the AGV, the AGV comprising a pair of first driving wheels controlled by a first motor, a pair of second driving wheels controlled by a second motor, a load-bearing lifting module for carrying a load 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 control instructions, and generates a travel path, a first execution instruction, a second execution instruction and a third execution instruction according to the control instructions;

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

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

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

[0067] S31: 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 loaded 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 wheels as front drives 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 driving wheels as rear drives to travel along the travel path.

[0070] Specifically, in the present embodiment, in order to further better illustrate the technical principle of the present method, a schematic diagram of the existing structure of the driving wheel control based AGV is provided as shown in the figure, which is provided with a pair of first driving wheels (100) driven and controlled by a first motor (110), a pair of second driving wheels (300) driven and controlled by a second motor (310), and a load-bearing lifting module (400) driven and controlled by a third motor (420). Figure 2 As shown in the figure, the existing structure of the driving wheel control based AGV is provided with a pair of first driving wheels (100) driven and controlled by a first motor (110), a pair of second driving wheels (300) driven and controlled by a second motor (310), and a load-bearing lifting module (400) driven and controlled by a third motor (420). Figure 2 Figure 2 Figure 2 Figure 2 Figure 2 ​​​​The load-bearing lifting module (210) driven and controlled by the control module (200) and the instruction receiving module (210) for receiving instructions Figure 2 The load-bearing lifting module (210) driven and controlled by the control module (200) and the instruction receiving module (210) for receiving instructions Figure 2 The load-bearing lifting module (210) driven and controlled by the control module (200) and the instruction receiving module (210) for receiving instructions

[0071] In step S1, the instruction receiving module receives control instructions from the user or the system, and generates corresponding travel paths and execution instructions, the travel paths being the movement routes that the AGV needs to follow, and the control instructions generating first, second and third execution instructions, respectively indicating the first, second and third motors to perform corresponding actions.

[0072] When the load-bearing lifting module is in an empty state, i.e., the AGV is in an empty state, steps S21 and S22 are executed:

[0073] In step S21, the AGV carries goods to the target location according to the travel path, and the first drive wheel is a rear drive wheel for pushing the AGV forward during travel. During control of the first drive wheel, the first motor adjusts the target speed of the motor to enable the first drive wheel to obtain sufficient power to complete the first execution instruction. Here, the positive direction indicates the direction, assuming that the direction of the AGV to the destination to obtain goods is the positive direction, then the direction of the AGV to return the goods to the starting location is the reverse direction.

[0074] In step S22, the second drive wheel is a front drive wheel for changing the direction of travel of the AGV, and the second motor adjusts the target speed of the motor during control of the second drive wheel to enable the second drive wheel to obtain sufficient power to complete the turning.

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

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

[0077] In step S32, during the return trip, the first drive wheel is converted into a front drive wheel. Due to the increase in load, the front drive wheel not only needs to realize the function of turning, but also needs to push the AGV forward, so the first motor adjusts the target speed of the motor to increase the output, so that the first drive wheel smoothly executes the first execution instruction and overcomes the load weight.

[0078] In step S33, the second motor outputs a corresponding reverse motor target speed to convert the second drive wheel into a rear drive wheel, thereby realizing the function of pushing the AGV forward.

[0079] When the load-lifting module is in a load 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, reduce the speed change and steering error caused by the load, and enable the AGV to maintain high efficiency and stable operation performance under the load state, thereby improving the safety and reliability during transportation. In the empty state, the forward target speed of the first motor and the second motor drives the AGV to realize normal driving and steering actions, ensuring the flexibility of the AGV in the empty state, so that it can accurately drive along the driving path and smoothly perform the steering action, 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-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, improving the operation efficiency of the equipment, especially in scenarios requiring frequent lifting operations.

[0080] Preferably, when the load-lifting module is in a load state, the second motor drives the second drive wheel as a rear drive to drive along the driving path, and the first motor drives the first drive wheel as a front drive to drive along the driving path without performing a steering action, the motor output energy obtained by the first drive wheel and the second drive wheel satisfies the relationship:

[0081] P 前 : P 后 = 1:1;

[0082] wherein P 前 represents the first motor output energy obtained by the first drive wheel, and P 后 represents the second motor output energy obtained by the second drive wheel.

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

[0084] P 前 : P 后 = 1+kθ:1-kθ;

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

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

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

[0088] Further, when the load lifting module has no load, the output energy of the first motor and the speed of the first 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 represents the output energy of the first motor or the second motor.

[0091] Specifically, when the load lifting module has no load, the first driving wheel serves as the rear driving wheel and only needs to push the AGV forward without the need to control steering, and when the load lifting module is in a load state, the second driving wheel serves as the rear driving wheel and also only needs to push the AGV forward without the need to control steering, and the relationship between the output energy of all motors and the speed of the driving wheel satisfies Assuming that the driving torque T of the driving wheel is 60 Nm, the speed v 轮 of the driving wheel is 2 m / s, and the radius r of the driving wheel is 0.3 m, the output energy P 出 of the first motor or the second motor is 400 W according to the above formula.

[0092] Preferably, when the third motor drives the load lifting module to perform a uniform lifting load action according to the third execution instruction, the motor output energy obtained by the load lifting module satisfies the relationship:

[0093] P 升 = ΔL·v 升 ;

[0094] where P升 The third motor output energy obtained by the load-bearing lifting module, ΔL represents the load change of the load-bearing lifting module, v 升 This indicates the lifting speed of the load-bearing lifting module;

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

[0096] P 升 =ΔL(g+a)·v 升 ;

[0097] Among them, P 升 The third motor output energy obtained by the load-bearing lifting module, ΔL represents the load change of the load-bearing lifting module, g represents the acceleration due to gravity, a represents the acceleration of the load-bearing lifting module during acceleration or deceleration, and v 升 This indicates the lifting speed of the load-bearing lifting module.

[0098] Specifically, assuming the load change is 100kg and the lifting speed is v 升 = 2 m / s², gravitational acceleration is 9.8 m / s² 2 The acceleration or deceleration is a = 1 m / s². 2 Under constant speed conditions, the load-bearing lifting module requires 200W of energy. The third motor needs to be adjusted to the corresponding target speed in order to output enough energy to the load-bearing lifting module to achieve the lifting action.

[0099] During acceleration or deceleration, taking acceleration as an example, according to the relationship P... 升 =ΔL(g+a)·v 升 The third motor needs to output 2160W of energy to achieve the purpose of accelerating upward. Similarly, when decelerating upward, the acceleration is vertically downward, so the value of 'a' can be positive or negative. The energy calculation takes into account the combined effects of gravitational acceleration and acceleration, ensuring that the motor can provide appropriate energy under load conditions for acceleration, deceleration and lifting to meet the load lifting requirements.

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

[0101] The output energy of the first motor is adjusted according to the speed of the first drive wheel in the first execution command, thereby adjusting the target speed of the first motor.

[0102] The output energy of the second motor is adjusted according to the steering amplitude and steering angular velocity of the second drive wheel in the second execution command, thereby adjusting the target speed of the second motor;

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

[0104] The output energy of the second motor is adjusted according to the load change amount and the speed of the second drive wheel in the second execution instruction, and the target rotating speed of the second motor is adjusted;

[0105] The output energy of the first motor is adjusted according to the load change amount and the speed, steering amplitude and steering angular speed of the first drive wheel in the first execution instruction, and the target rotating speed of the first motor is adjusted;

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

[0107] Specifically, in the no-load state, the first drive wheel is the rear drive wheel, and the first drive wheel only needs to load to push the AGV forward, so the target rotating speed of the first motor is directly related to the speed setting of the first drive wheel, and the higher the speed, the greater the energy required by the first drive wheel, and the higher the target rotating speed of the first motor. 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 rotating speed of the second motor is directly related to the steering amplitude and steering angular speed setting of the second drive wheel, and the greater the steering amplitude and the greater the steering angular speed, the greater the target rotating speed of the motor.

[0108] In the load state, the first drive wheel needs to push the AGV forward and realize the steering of the AGV, so 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 rotating speed of the first motor needs to be increased to adapt to the increase of the load, and the greater the load, the higher the target rotating speed of the first motor, so as to provide enough power to overcome the additional resistance. The target rotating speed of the first motor is related to the speed setting of the first drive wheel, and the higher the speed, the higher the rotating speed of the motor needs to be provided to maintain the speed. The steering operation needs more power to maintain stability and direction control, so the rotating speed of the motor will also be affected to a certain extent. The second drive wheel realizes the forward movement of the AGV, and the higher the speed of the second drive wheel, the greater the load, and the faster the rotating speed of the second motor required. When the load of the load-bearing lifting module increases, more motor output energy is required to complete the lifting operation, and the target rotating speed of the third motor needs to be adjusted according to the load change amount to ensure that the lifting module can work normally in the load state. The target rotating speed of the lifting module is related to the lifting speed, and in the load state, the lifting speed needs to be adjusted to ensure that the load can be lifted stably, so the target rotating speed of the third motor also needs to be adjusted to match the change of the lifting speed.

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

[0110]

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

[0112] Specifically, when the target rotating speed of the motor is adjusted, the output energy of the motor needs to be converted, assuming that the output energy P 出 of the motor is 500W, and the torque T generated by the motor is 1.5N·M, the target rotating speed of the motor is 3183RPM obtained by substituting the above formula.

[0113] Further, when the target rotating speeds of the first motor, the second motor and the third motor are adjusted, it is judged whether the target rotating speed of the motor is lower than the preset motor turning speed, if yes, the current control mode of MTPA is adopted to generate the 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 generate the maximum motor rotating speed using the minimum current, that is, the current control mode of MTPA is adopted, wherein the output current I is divided into the current I d output to the d-axis and the current I q output to the q-axis, wherein the current I q mainly controls the current in the torque direction, and the current I d mainly controls the current in the magnetic field direction. The embodiment mainly aims to weaken the motor magnetic field, reduce the back electromotive force under the condition of limited input voltage of the power supply, and achieve the purpose of improving the motor rotating speed. Therefore, in the present application, it is first judged whether the current rotating speed is lower than the turning speed, because the current rotating speed is lower than the turning speed, it means that the motor is still operating in the constant torque zone, and it is not necessary to reduce the motor back electromotive force or increase the speed by weakening the magnetic flux. At this time, the current I d is set to 0 by adopting the MTPA mode, and then the minimum current I q is calculated to generate the maximum torque as much as possible, so that the motor can quickly increase the rotating speed, and the current rotating speed can quickly rise. Since the control mode of I d =0, the d-axis current of the motor is always zero, which reduces the electromagnetic interference and vibration caused by the change of the d-axis current, and this is helpful to maintain the stable operation of the motor. Finally, I q and I d can be inversely PARK transformed to generate Ua and Ub control signals, and the Ua and Ub are delivered to the SVPWM module to generate a driving signal to control the motor.

[0116] In another embodiment, when adjusting the target rotating speed of the first motor, the second motor and the third motor, it is judged whether the target rotating speed of the motor is higher than the preset motor turning speed, if yes, the d-axis current is obtained according to the operating parameter, the design parameter and the target rotating speed of the motor, and the limit value of the q-axis current is obtained according to the maximum current and the d-axis current;

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

[0118] Specifically, when the target rotating speed of the motor is higher than the preset motor turning speed, the output of the motor will increase, which causes the magnetic flux level inside the motor to increase, and the motor will consume more energy to maintain the magnetic field. Therefore, in order to reduce the magnetic flux, when the target rotating speed of the motor is higher than the preset motor turning speed, the control of the d-axis current and the limitation of the q-axis current are performed based on the operating parameter and the design parameter, which can accelerate to meet the requirements of the target step size and the step frequency, and the q-axis current is limited. If the q-axis current I d is too high, it may cause the motor to generate a larger torque fluctuation when dynamically responding, which affects 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. Finally, I q and I d are subjected to inverse PARK transformation to generate Ua and Ub control signals, which are transmitted to the SVPWM module to generate a driving signal to control the motor.

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

[0120] The design parameter includes: a rated current of the motor, a rated rotating speed of the motor.

[0121] The step of obtaining the d-axis current is as follows:

[0122] The given current I qRef of the q-axis is obtained in real time, and input into a low-pass filter to obtain a first parameter I qRef ′ q Ref ;

[0123] The feedback current I q of the q-axis is obtained in real time, and input into a low-pass filter to obtain a second parameter I q ′ q

[0124] The first parameter I q ′ Ref and the second parameter I q ​​The difference E between the given current and the feedback current is calculated, and the difference E is taken as the input of the PI controller to obtain the current feedback given item D1;

[0125] According to the rated current I n and the rated rotating speed ω n The amplification coefficient Kc of the current feedforward given item is calculated;

[0126] The current rotating speed increment is obtained, and the rotating speed increment is adjusted by the amplification coefficient Kc to obtain the current feedback given item D2;

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

[0128] Specifically, when the motor is controlled to drive the wheel, the given current and the feedback current of the q-axis are obtained in real time, and a low-pass filter is applied for processing, so that more stable and accurate current parameters can be obtained. This method helps to accurately control the operation of the motor and improves the stability and reliability. The difference E between the given current and the feedback current is calculated, and the difference E is taken as the input of the PI controller to obtain the current feedback given item D1. The PI controller can effectively reduce the error and improve the accuracy of current control. The determination of the calculated amplification coefficient Kc is based on the rated current and the rated rotating speed of the motor, and the rotating speed increment is adjusted by the amplification coefficient Kc, so that the motor can operate in an efficient and stable state. In the present application, the feedback control and the feedforward control are combined, the d-axis current is obtained by simple addition operation, and the d-axis current can be accurately obtained without relying on complex algorithms. The current feedforward given item D1 can improve the speed response of the motor rotating speed during rapid switching, and the current feedback given item can ensure the speed stability of the motor under heavy load. The method has less calculation amount, simple structure and high operation stability.

[0129] In the description of the present application, 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 application, the exemplary description of the above terms does not necessarily refer to 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.

[0130] Although the embodiments of the present application have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and purposes of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. An AGV control method based on drive wheel operation, 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; Its features are, The control method includes: The instruction transceiver module receives control instructions and generates a travel path, a first execution instruction, a second execution instruction, and a third execution instruction based on the control instructions. 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 command to drive the first drive wheel as the rear drive to travel along the travel path; The second motor outputs the corresponding forward motor target speed according to the second execution command to drive the second drive wheel as the front drive to perform the steering action; The third motor outputs a target motor speed according to the third execution command to drive the load-bearing lifting module to perform lifting and lowering operations 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 command and the load weight to drive the first drive wheel as the front drive to travel along the travel path and / or perform steering actions; The second motor outputs the corresponding reverse motor target speed according to the second execution command and the load weight to drive the second drive wheel as the rear drive to travel along the travel path; When the third motor outputs the corresponding target speed according to the third execution command to drive the load-bearing lifting module to perform a uniform lifting load action, the motor output energy obtained by the load-bearing lifting module satisfies the following relationship: in, The energy output from the third motor is obtained for the load-bearing lifting module. This indicates the change in load on the lifting module. This indicates the lifting speed of the load-bearing lifting module; When the third motor outputs the corresponding target speed according to the third execution command to drive the load-bearing lifting module to perform acceleration or deceleration lifting of the load, the motor output energy acquired or lost by the load-bearing lifting module satisfies the following relationship: in, The energy output from the third motor is obtained for the load-bearing lifting module. This indicates the change in load on the lifting module. Represents gravitational acceleration. This indicates the acceleration of the load-bearing lifting module during acceleration or deceleration. This indicates the lifting speed of the load-bearing lifting module.

2. The control method according to claim 1, characterized in that, When the load-bearing lifting module is under load, the second motor drives the second drive wheel as the rear drive to travel along the path, and the first motor drives the first drive wheel as the front drive to travel along the path but does not perform a steering action. The motor output energy obtained by the first drive wheel and the second drive wheel satisfies the following relationship: ； in, This represents the energy output from the first motor that the first drive wheel receives. This indicates the output energy of the second motor obtained by the second drive wheel; When the load-bearing lifting module is under load, the second motor drives the second drive wheel as the rear drive to travel along the path, and the first motor drives the first drive wheel as the front drive to travel along the path and perform a steering action. The motor output energy obtained by the first drive wheel and the second drive wheel satisfies the following relationship: ； in, Indicates the steering angle of the first drive wheel. This represents the proportional constant of the control steering angle determined by the AGV itself in relation to the power distribution. This represents the energy output from the first motor that the first drive wheel receives. This indicates the output energy of the second motor obtained by the second drive wheel.

3. The control method according to claim 2, characterized in that, When the lifting module is unloaded, the output energy of the first motor and the speed of the first drive wheel satisfy the following relationship: When the lifting module is under load, the output energy of the second motor and the speed of the second drive wheel satisfy the following relationship: in, This represents the driving torque on the drive wheels. Indicates the speed of the drive wheels. Indicates the radius of the drive wheel. This indicates the output energy of the first or second motor.

4. The control method according to claim 1, characterized in that, When the load-bearing lifting module is in an unloaded state: The output energy of the first motor is adjusted according to the speed of the first drive wheel in the first execution command, thereby adjusting the target speed of the first motor. The output energy of the second motor is adjusted according to the steering amplitude and steering angular velocity of the second drive wheel in the second execution command, thereby adjusting the target speed of the second motor; When the load-bearing lifting module is under load: The output energy of the second motor is adjusted according to the load change and the speed of the second drive wheel in the second execution command, thereby adjusting the target speed of the second motor. The output energy of the first motor is adjusted according to the load change and the speed, steering amplitude and steering angular velocity of the first drive wheel in the first execution command, thereby adjusting 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 command, thereby adjusting the target speed of the third motor.

5. The control method according to claim 4, characterized in that, In adjusting the output energy of the first motor and thus the target speed of the first motor, the output energy of the first motor and the target speed of the first motor satisfy the following relationship: ； in, It is the torque generated by the motor. This indicates the output energy of the first motor. This indicates the target rotational speed of the first motor per minute.

6. The control method according to claim 5, characterized in that, When adjusting the target speeds of the first, second, and third motors, it is determined whether the target speed of the motor is lower than the preset motor turning speed. If so, then... The current control method generates the corresponding shaft and The current in the shaft; Will shaft current and The shaft current is input to the controller, and the result is... shaft and The voltage of the shaft, according to shaft and The voltage on the shaft drives the motor to run.

7. The control method according to claim 6, characterized in that, When adjusting the target speeds of the first, second, and third motors, it is determined whether the target speed of the motor is higher than the preset motor turning speed. If so, the speed is determined based on the motor's operating parameters, design parameters, and the target speed. The shaft current, based on the maximum current and Current acquisition of the shaft Shaft current limit; Will shaft current and The shaft current is input to the controller, and the result is... shaft and The voltage of the shaft, according to shaft and The voltage on the shaft drives the motor to run.

8. The control method according to claim 7, characterized in that, The operating parameters include: The given current of the shaft, Feedback current of the shaft; The design parameters include: the rated current of the motor and the rated speed of the motor.

9. The control method according to claim 8, characterized in that, The acquisition The steps for controlling the shaft current are as follows: Real-time acquisition The given current of the shaft , give current The input is fed into a low-pass filter to obtain the first parameter. ; Real-time acquisition Shaft feedback current , give 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 , the difference As the input to the PI controller, the current feedback setpoint D1 is obtained; According to the rated current and rated speed Calculate the amplification factor Kc of the current feedforward reference term; Obtain the current speed increment, adjust the speed increment through the amplification factor Kc, and obtain the current feedback setpoint D2; The result is obtained by adding the feedback given term D1 and the feedforward given term D2. shaft current .

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