An AGV device maximum speed control method and device, a terminal and a storage medium

Abstract

The application belongs to the technical field of automobiles, and particularly relates to an AGV device maximum speed control method, device, terminal and storage medium. The pressure sensor can obtain the pressure of the AGV trolley goods pallet and goods on the sensor, and the goods quality is obtained through calculation, and then the total mass of the AGV trolley is obtained. The maximum speed of the AGV trolley under the safe state can be obtained through calculation, and the maximum speed of the AGV trolley is accurately controlled. Thus, the maximum speed of the AGV trolley is increased under the condition of ensuring safety, the goods transportation time and the return time of the AGV trolley are reduced, and the working efficiency of the AGV trolley is greatly improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of automobiles, in particular to an AGV device maximum speed control method, device, terminal and storage medium. BACKGROUND

[0002] Automated Guided Vehicle, referred to as AGV, refers to a transport vehicle equipped with electromagnetic or optical automatic navigation device, which can travel along the specified navigation path, has safety protection and various transfer functions. At present, AGV trolley has been widely used in automatic logistics handling.

[0003] In order to ensure that the AGV trolley can travel stably under full load condition, the AGV trolley is usually designed with full load condition and AGV trolley maximum speed as the design condition for motor selection and other designs. However, in actual working condition, the AGV trolley often works in non-full load condition. In this condition, the motor of the AGV trolley does not reach the rated power, and the maximum speed actually has room for improvement. The AGV trolley can reach the target location at a faster speed, save transportation time and increase the handling efficiency of the AGV trolley. For example, after the AGV trolley completes the task of delivering goods to the target location, the AGV trolley returns to the starting point to reload. In this condition, the AGV trolley is in empty state. In this condition, the AGV trolley runs at a preset fixed maximum speed, and the output power of the AGV trolley driving motor is far below the rated power of the motor. At this time, the output power of the AGV trolley driving motor can be increased under the premise of ensuring the safety of the AGV trolley, the maximum speed of the AGV trolley is increased, the AGV trolley returns to the starting point more quickly, the return time is saved, and the working efficiency of the AGV trolley is greatly improved. SUMMARY

[0004] The application provides an AGV device maximum speed control method, device, terminal and storage medium. The pressure sensor can obtain the pressure of the AGV trolley goods pallet and goods on the sensor, and the weight of the goods is obtained by calculation, and the total weight of the AGV trolley is obtained. The maximum speed of the AGV trolley under safe condition can be obtained by calculation, and the maximum speed of the AGV trolley is accurately controlled. Thus, the maximum speed of the AGV trolley is increased under the premise of safety, the goods transportation time and the return time of the AGV trolley are reduced, the working efficiency of the AGV trolley is greatly improved, and the above-mentioned deficiencies of the prior art are solved.

[0005] The technical scheme of the application is described in combination with the drawings as follows:

[0006] In a first aspect, the application embodiment provides an AGV device maximum speed control method, comprising:

[0007] Step 1: Obtain the cargo weight of the AGV vehicle;

[0008] Step 2: Obtain the theoretical maximum speed V1 of the AGV based on the cargo mass and motor rated power of the AGV.

[0009] Step 3: Obtain the maximum speed V2 of the AGV under safe conditions based on the cargo mass and maximum braking distance of the AGV;

[0010] Step 4: Determine the maximum speed V of the AGV under the current load based on the theoretical maximum speed V1 and the maximum speed V2 of the AGV under safe conditions;

[0011] Step 5: Use an encoder to obtain the current speed V of the AGV. n ;

[0012] Step 6: Based on the current speed V of the AGV vehicle n Determine the speed difference ΔV based on the maximum speed V under the current load;

[0013] Step 7: Perform PID control on the AGV based on the speed difference ΔV to stably control the AGV at its maximum speed.

[0014] Furthermore, the specific method for step one is as follows:

[0015] Use pressure sensors to obtain the weight of goods on the AGV (Automated Guided Vehicle).

[0016]

[0017]

[0018] In the formula, m h The mass of goods carried by the AGV; m i The mass of the i-th pressure sensor is measured; V i V represents the voltage signal output by the i-th pressure sensor when it is subjected to pressure. max The full-scale output voltage of the pressure sensor; m max Let i be the full-scale mass of the pressure sensor; 1 ≤ i ≤ 4.

[0019] Furthermore, the specific method for step two is as follows:

[0020] Based on the mass m of the AGV trolley c The cargo mass m of the AGV cart h The total mass m of the AGV is obtained as shown in formula (3):

[0021] m = m h +m c (3);

[0022] The dynamics of the AGV are analyzed as shown in formula (4):

[0023] F t =F f +F i +F w +F j (4);

[0024] In the formula, F t For driving force; F f F represents rolling resistance. i For slope resistance; F w For air resistance; F j To increase resistance;

[0025] Assuming the factory is on flat ground and the AGV has reached its maximum speed with zero acceleration resistance, ignoring air resistance, the equation can be simplified to formula (5):

[0026] F t =F f (5);

[0027] F f =m×g×f (6);

[0028] In the formula, g is taken as 9.8 m / s 2 , where is the rolling resistance coefficient;

[0029] The total rated power of the AGV trolley motor is calculated as shown in formula (7):

[0030] P = k × P k (7);

[0031] In the formula, P is the total rated power of the AGV trolley motors; k is the number of AGV trolley motors; P k The rated power of a single motor in the AGV (Automated Guided Vehicle) trolley;

[0032] The theoretical maximum speed V1 of the AGV is calculated as shown in formula (8):

[0033]

[0034] Therefore

[0035] Furthermore, the specific method for step three is as follows:

[0036] The maximum speed V2 of the AGV under safe conditions is calculated by the maximum braking distance of the AGV, as shown in formula (10):

[0037]

[0038] In the formula, θ is the rotation angle of the brake pad at the maximum braking distance; S is the maximum braking distance; and R is the tire radius.

[0039] The energy absorbed by the brake pads at the maximum braking distance is calculated as shown in formula (11):

[0040] E = P s ×T=M×W×T=M×θ (11);

[0041] In the formula, E is the energy absorbed by the brake pads at the maximum braking distance; P s Where M is the braking power; T is the braking time; M is the braking torque of the brake; W is the angular velocity of the brake pads.

[0042] The maximum speed V2 of the AGV under safe conditions is calculated as shown in formula (12):

[0043]

[0044] Therefore

[0045] Furthermore, the specific method for step four is as follows:

[0046] Compare the theoretical maximum speed V1 of the AGV and the maximum speed V2 of the AGV under safe conditions, and take the minimum value as the maximum speed V of the AGV under the current load, as shown in formula (14):

[0047] V = min(V1, V2) (14).

[0048] Furthermore, the specific method for step five is as follows:

[0049] The AGV trolley motor speed n is calculated as shown in formula (15):

[0050]

[0051] In the formula, x is the number of pulses output by the encoder within 1 second; X is the encoder resolution;

[0052] Calculate the current speed V of the AGV based on the motor speed n of the AGV. n As shown in formula (16):

[0053]

[0054] In the formula, r is the rolling radius of the drive wheel; i0 is the transmission ratio of the transmission system.

[0055] Furthermore, the specific method for step six is ​​as follows:

[0056] △V=VV n (17).

[0057] Furthermore, the specific method for step seven is as follows:

[0058] The speed difference ΔV is input into the PID controller, and the speed control change is obtained through a preset PID algorithm, i.e.:

[0059]

[0060] In the formula, u(t) is the output of the PID controller; e(t) is the input of the PID controller, i.e., the deviation signal between the given value and the output value of the controlled object; K p T is the proportionality coefficient; i T is the integration time constant; d Let be the differential time constant; discretize equation (18) as shown in equation (19):

[0061]

[0062] Based on the incremental PID control principle, and using the AGV speed signal collected during the AGV's movement, the change in AGV speed control at time n is calculated as ΔV(n), as shown in formula (20):

[0063] △V(n)=K p [V(n)-V(n-1)]+K i V(n)+K d [V(n)-2V(n-1)+V(n-2)] (20);

[0064] In the formula, The integral coefficient; These are the differential coefficients;

[0065] Therefore, the speed command V output by the PID controller at time n is obtained. s (n), as shown in formula (21):

[0066] V s (n)=V s (n-1)+K p [V(n)-V(n-1)]+K i V(n)+K d [V(n)-2V(n-1)+V(n-2)] (1).

[0067] Secondly, embodiments of the present invention also provide a maximum speed control device for an AGV device, comprising:

[0068] The acquisition module is used to obtain the weight of the goods carried by the AGV.

[0069] The first calculation module is used to obtain the theoretical maximum speed V1 of the AGV based on the cargo mass and motor rated power of the AGV.

[0070] The second calculation module is used to obtain the maximum speed V2 of the AGV under safe conditions based on the cargo mass and maximum braking distance of the AGV.

[0071] The third calculation module is used to determine the maximum speed V of the AGV under the current load based on the theoretical maximum speed V1 of the AGV and the maximum speed V2 of the AGV under safe conditions.

[0072] The fourth calculation module is used to obtain the current speed V of the AGV using an encoder. n ;

[0073] The fifth calculation module is used to calculate the current speed V of the AGV. n Determine the speed difference ΔV based on the maximum speed V under the current load;

[0074] The control module is used to perform PID control on the AGV based on the speed difference ΔV to stably control the AGV at its maximum speed.

[0075] Thirdly, a terminal is provided, including:

[0076] One or more processors;

[0077] Memory for storing the one or more processor-executable instructions;

[0078] Wherein, the one or more processors are configured as follows:

[0079] Perform the method described in the first aspect of the embodiments of the present invention.

[0080] Fourthly, a non-transitory computer-readable storage medium is provided, wherein when instructions in the storage medium are executed by a processor of a terminal, the terminal is enabled to perform the method described in the first aspect of the present invention.

[0081] Fifthly, an application product is provided, which, when running on a terminal, causes the terminal to execute the method described in the first aspect of the present invention.

[0082] The beneficial effects of this invention are as follows:

[0083] This invention can ensure the safety of AGV trolley driving, improve the output power of AGV trolley drive motor, reduce transportation time, and increase the working efficiency of AGV trolley. Attached Figure Description

[0084] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0085] Figure 1 This is a flowchart of a maximum speed control method for an AGV device according to the present invention;

[0086] Figure 2 This is a front view diagram of the AGV (Automated Guided Vehicle).

[0087] Figure 3 This is a side view of the AGV (Automated Guided Vehicle).

[0088] Figure 4 Flowchart of PID speed control for AGV (Automated Guided Vehicle) vehicle;

[0089] Figure 5 This is a schematic diagram of the maximum speed control device for an AGV device according to the present invention;

[0090] Figure 6 This is a schematic block diagram of a terminal structure.

[0091] In the picture:

[0092] 1. AGV trolley; 2. Pressure sensor; 3. Carrying pallet. Detailed Implementation

[0093] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0094] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0095] Example 1

[0096] Figure 1This is a flowchart of a maximum speed control method for an AGV device provided in Embodiment 1 of the present invention. This embodiment is applicable to the case of maximum speed control of an AGV device. The method can be executed by an AGV device maximum speed control device in the embodiment of the present invention, which can be implemented in software and / or hardware.

[0097] The execution subject in this embodiment is an AGV (Automated Guided Vehicle). The AGV can be an intelligent transport vehicle, an intelligent forklift, or other equipment with the same or similar functions as an intelligent transport vehicle. This embodiment does not limit it in this way.

[0098] It is understandable that this embodiment applies to the movement of the AGV under non-full-load conditions. AGVs are typically designed with full-load conditions and maximum speed as design criteria for motor selection and other aspects. However, in actual operation, AGVs frequently operate under non-full-load conditions. If they travel at a preset fixed maximum speed, the AGV motor will not reach its rated power, and the maximum speed will have room to increase, affecting the AGV's efficiency. For example, if the AGV has delivered goods to the target location and is returning to the transport location, it will be in an unloaded state, and the AGV motor output power will be far less than its rated power. Traveling at the preset maximum speed will result in low efficiency. Therefore, this embodiment increases the AGV's maximum speed based on the weight of the goods under non-full-load conditions, reducing the time it takes to reach the target location and significantly improving the AGV's efficiency. Furthermore, differentiated control based on the weight of the goods can achieve the highest AGV efficiency while ensuring safety.

[0099] Figure 2 , Figure 3 This is a schematic diagram of the AGV (Automated Guided Vehicle) structure according to an embodiment of the present invention. The intelligent AGV device includes an AGV trolley 1, a pressure sensor 2, and a support tray 3. The pressure sensor 2 is a device or apparatus that can sense pressure signals and convert them into usable output electrical signals according to a certain rule. The pressure sensor 2 typically consists of a pressure-sensitive element and a signal processing unit.

[0100] like Figure 2 As shown, four pressure sensors 2 are installed at the four corners of the lower end of the carrying pallet 3. After the carrying pallet 3 carries the goods, it will output electrical signals of different magnitudes depending on the weight of the goods. Based on the magnitude of the electrical signals, we can obtain the weight of the goods on the AGV.

[0101] See Figure 1 and Figure 4 A method for controlling the maximum speed of an AGV device, comprising:

[0102] Step 1: Obtain the cargo mass of AGV 1;

[0103] The weight of the goods on the AGV is obtained using pressure sensor 2.

[0104]

[0105]

[0106] In the formula, m h The mass of goods carried by the AGV; m i The mass of the i-th pressure sensor is measured; V i V represents the voltage signal output by the i-th pressure sensor when it is subjected to pressure. max The full-scale output voltage of the pressure sensor; m max Let i be the full-scale mass of the pressure sensor; 1 ≤ i ≤ 4.

[0107] Step 2: Obtain the theoretical maximum speed V1 of the AGV trolley 1 based on the cargo mass and motor rated power;

[0108] Based on the mass m of the AGV trolley c The cargo mass m of the AGV cart h The total mass m of the AGV is obtained as shown in formula (3):

[0109] m = m h +m c (3);

[0110] The dynamics of the AGV are analyzed as shown in formula (4):

[0111] F t =F f +F i +F w +F j (4);

[0112] In the formula, F t For driving force; F f F represents rolling resistance. i For slope resistance; F w For air resistance; F j To increase resistance;

[0113] Assuming the factory is on flat ground and the AGV has reached its maximum speed with zero acceleration resistance, ignoring air resistance, the equation can be simplified to formula (5):

[0114] F t =F f (5);

[0115] Ff =m×g×f (6);

[0116] In the formula, g is taken as 9.8 m / s 2 , where is the rolling resistance coefficient;

[0117] The total rated power of the AGV trolley motor is calculated as shown in formula (7):

[0118] P = k × P k (7);

[0119] In the formula, P is the total rated power of the AGV trolley motors; k is the number of AGV trolley motors; P k The rated power of a single motor in the AGV (Automated Guided Vehicle) trolley;

[0120] The theoretical maximum speed V1 of the AGV is calculated as shown in formula (8):

[0121]

[0122] Therefore

[0123] Step 3: Obtain the maximum speed V2 of the AGV under safe conditions based on the cargo mass and maximum braking distance of the AGV 1;

[0124] Since the safety of AGV 1 needs to be considered, the maximum speed of AGV 1 under safe conditions is calculated by the maximum braking distance of AGV 1. Here, a drum brake is used as an example: as shown in formula (10):

[0125]

[0126] In the formula, θ is the rotation angle of the brake pad at the maximum braking distance; S is the maximum braking distance; and R is the tire radius.

[0127] The energy absorbed by the brake pads at the maximum braking distance is calculated as shown in formula (11):

[0128] E = P s ×T=M×W×T=M×θ (11);

[0129] In the formula, E is the energy absorbed by the brake pads at the maximum braking distance; P s Where M is the braking power; T is the braking time; M is the braking torque of the brake; W is the angular velocity of the brake pads.

[0130] The maximum speed V2 of the AGV under safe conditions is calculated as shown in formula (12):

[0131]

[0132] Therefore

[0133] Step 4: Determine the maximum speed V of the AGV under the current load based on the theoretical maximum speed V1 and the maximum speed V2 of the AGV under safe conditions;

[0134] The maximum speed under the current load is determined based on the cargo mass. The theoretical maximum speed of AGV 1 is determined by the motor power and driving resistance. Only when the power and driving resistance of AGV 1 are balanced can AGV 1 reach the theoretical maximum speed. However, under the condition that other conditions remain unchanged, the faster the speed of AGV 1 is, the greater the braking distance will be, and the safety will be affected. Therefore, it is necessary to calculate the maximum speed of AGV 1 under safe conditions by using the maximum braking distance and compare it with the theoretical maximum speed of AGV 1. The minimum value of the two is taken to ensure the safety and high efficiency of AGV 1, as shown in formula (14).

[0135] V = min(V1, V2) (14).

[0136] Understandably, when not fully loaded, traveling at a preset fixed maximum speed will cause the motor output power of AGV 1 to be lower than its rated power, affecting the working efficiency of AGV 1. Therefore, it is necessary to determine a maximum speed based on the weight of the goods to ensure the safe operation of AGV 1, thereby improving its working efficiency. Thus, this embodiment modifies the maximum speed of AGV 1 based on the original preset fixed maximum speed to improve working efficiency.

[0137] Step 5: Use an encoder to obtain the current speed V of the AGV. n ;

[0138] The AGV trolley motor speed n is calculated as shown in formula (15):

[0139]

[0140] In the formula, x is the number of pulses output by the encoder within 1 second; X is the encoder resolution;

[0141] Calculate the current speed V of the AGV based on the motor speed n of the AGV. n As shown in formula (16):

[0142]

[0143] In the formula, r is the rolling radius of the drive wheel; i0 is the transmission ratio of the transmission system.

[0144] Step 6: Based on the current speed V of the AGV vehicle nDetermine the speed difference ΔV based on the maximum speed V under the current load;

[0145] △V=VV n (17).

[0146] See Figure 4 Step 7: Perform PID control on AGV 1 according to the speed difference ΔV. PID control, namely proportional integral derivative control, is based on the given value and the actual output value to form the control deviation. The deviation is linearly combined according to the proportional, integral and derivative to form the control quantity to control the controlled object. PID control has the characteristics of simple algorithm, good robustness and high reliability.

[0147] The speed difference ΔV is input into the PID controller, and the speed control change is obtained through a preset PID algorithm, i.e.:

[0148]

[0149] In the formula, u(t) is the output of the PID controller; e(t) is the input of the PID controller, i.e., the deviation signal between the given value and the output value of the controlled object; K p T is the proportionality coefficient; i T is the integration time constant; d Let be the differential time constant; discretize equation (18) as shown in equation (19):

[0150]

[0151] Based on the incremental PID control principle, and using the AGV speed signal collected during the AGV's movement, the change in AGV speed control at time n is calculated as ΔV(n), as shown in formula (20):

[0152] △V(n)=K p [V(n)-V(n-1)]+K i V(n)+K d [V(n)-2V(n-1)+V(n-2)] (20);

[0153] In the formula, The integral coefficient; These are the differential coefficients;

[0154] Therefore, the speed command V output by the PID controller at time n is obtained. s (n), as shown in formula (21):

[0155] V s (n)=V s (n-1)+K p [V(n)-V(n-1)]+K iV(n)+K d [V(n)-2V(n-1)+V(n-2)] (2).

[0156] In summary, the maximum speed of AGV 1 can be obtained based on the weight of the goods, and then, using the PID control principle described above, the speed can be adjusted according to the current speed V. n The difference between the speed of the AGV and its maximum speed V under the current load is used to obtain the speed control change of the AGV 1 at each moment, thereby stabilizing the speed of the AGV 1 and ensuring that the AGV 1 remains at its maximum speed.

[0157] Example 2

[0158] See Figure 5 An AGV device maximum speed control device, comprising:

[0159] The acquisition module is used to obtain the weight of the goods carried by the AGV.

[0160] The first calculation module is used to obtain the theoretical maximum speed V1 of the AGV based on the cargo mass and motor rated power of the AGV.

[0161] The second calculation module is used to obtain the maximum speed V2 of the AGV under safe conditions based on the cargo mass and maximum braking distance of the AGV.

[0162] The third calculation module is used to determine the maximum speed V of the AGV under the current load based on the theoretical maximum speed V1 of the AGV and the maximum speed V2 of the AGV under safe conditions.

[0163] The fourth calculation module is used to obtain the current speed V of the AGV using an encoder. n ;

[0164] The fifth calculation module is used to calculate the current speed V of the AGV. n Determine the speed difference ΔV based on the maximum speed V under the current load;

[0165] The control module is used to perform PID control on the AGV based on the speed difference ΔV to stably control the AGV at its maximum speed.

[0166] Example 3

[0167] Figure 6 This is a structural block diagram of a terminal provided in an embodiment of this application. The terminal can be the terminal described in the above embodiments. The terminal can be a portable mobile terminal, such as a smartphone or tablet computer. The terminal may also be referred to as user equipment, portable terminal, or other names.

[0168] Typically, a terminal includes a processor 301 and a memory 302.

[0169] Processor 301 may include one or more processing cores, such as a quad-core processor or an octa-core processor. Processor 301 may be implemented using at least one hardware form selected from DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), and PLA (Programmable Logic Array). Processor 301 may also include a main processor and a coprocessor. The main processor, also known as a CPU (Central Processing Unit), is used to process data in the wake-up state; the coprocessor is a low-power processor used to process data in the standby state. In some embodiments, processor 301 may integrate a GPU (Graphics Processing Unit), which is responsible for rendering and drawing the content to be displayed on the screen. In some embodiments, processor 301 may also include an AI (Artificial Intelligence) processor, which is used to handle computational operations related to machine learning.

[0170] The memory 302 may include one or more computer-readable storage media, which may be tangible and non-transitory. The memory 302 may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices or flash memory devices. In some embodiments, the non-transitory computer-readable storage media in the memory 302 are used to store at least one instruction, which is executed by the processor 301 to implement a maximum speed control method for an AGV device provided in this application.

[0171] In some embodiments, the terminal may also optionally include: a peripheral device interface 303 and at least one peripheral device. Specifically, the peripheral device includes at least one of: a radio frequency circuit 304, a touch display screen 305, a camera 306, an audio circuit 307, a positioning component 308, and a power supply 309.

[0172] The peripheral device interface 303 can be used to connect at least one I / O (Input / Output) related peripheral device to the processor 301 and the memory 302. In some embodiments, the processor 301, memory 302, and peripheral device interface 303 are integrated on the same chip or circuit board; in some other embodiments, any one or two of the processor 301, memory 302, and peripheral device interface 303 can be implemented on separate chips or circuit boards, which is not limited in this embodiment.

[0173] The radio frequency (RF) circuit 304 is used to receive and transmit RF (Radio Frequency) signals, also known as electromagnetic signals. The RF circuit 304 communicates with communication networks and other communication devices via electromagnetic signals. The RF circuit 304 converts electrical signals into electromagnetic signals for transmission, or converts received electromagnetic signals back into electrical signals. Optionally, the RF circuit 304 includes: an antenna system, an RF transceiver, one or more amplifiers, a tuner, an oscillator, a digital signal processor, a codec chipset, a user identity module card, etc. The RF circuit 304 can communicate with other terminals through at least one wireless communication protocol. This wireless communication protocol includes, but is not limited to: the World Wide Web, metropolitan area networks, intranets, various generations of mobile communication networks (2G, 3G, 4G, and 5G), wireless local area networks, and / or WiFi (Wireless Fidelity) networks. In some embodiments, the RF circuit 304 may also include circuitry related to NFC (Near Field Communication), which is not limited in this application.

[0174] The touch display screen 305 is used to display a UI (User Interface). This UI may include graphics, text, icons, videos, and any combination thereof. The touch display screen 305 also has the ability to collect touch signals on or above its surface. These touch signals can be input as control signals to the processor 301 for processing. The touch display screen 305 is used to provide virtual buttons and / or a virtual keyboard, also known as soft buttons and / or a soft keyboard. In some embodiments, there may be one touch display screen 305, which serves as the front panel of the terminal; in other embodiments, there may be at least two touch display screens, respectively disposed on different surfaces of the terminal or in a folded design; in still other embodiments, the touch display screen 305 may be a flexible display screen, disposed on a curved or folded surface of the terminal. Furthermore, the touch display screen 305 may be configured as a non-rectangular, irregular shape, i.e., a non-rectangular screen. The touch display screen 305 may be made of materials such as LCD (Liquid Crystal Display) or OLED (Organic Light-Emitting Diode).

[0175] Camera assembly 306 is used to acquire images or videos. Optionally, camera assembly 306 includes a front-facing camera and a rear-facing camera. Typically, the front-facing camera is used for video calls or selfies, and the rear-facing camera is used for taking photos or videos. In some embodiments, there are at least two rear-facing cameras, which are any one of a main camera, a depth-sensing camera, and a wide-angle camera, to achieve background blurring by fusion of the main camera and the depth-sensing camera, and panoramic shooting and VR (Virtual Reality) shooting by fusion of the main camera and the wide-angle camera. In some embodiments, camera assembly 306 may also include a flash. The flash can be a single-color temperature flash or a dual-color temperature flash. A dual-color temperature flash is a combination of a warm light flash and a cool light flash, which can be used for light compensation at different color temperatures.

[0176] Audio circuit 307 provides an audio interface between the user and the terminal. Audio circuit 307 may include a microphone and a speaker. The microphone is used to collect sound waves from the user and the environment, converting the sound waves into electrical signals that are input to processor 301 for processing, or input to radio frequency circuit 304 for voice communication. For stereo sound acquisition or noise reduction purposes, multiple microphones may be used, each located in a different part of the terminal. The microphone may also be an array microphone or an omnidirectional microphone. The speaker is used to convert electrical signals from processor 301 or radio frequency circuit 304 into sound waves. The speaker may be a conventional diaphragm speaker or a piezoelectric ceramic speaker. When the speaker is a piezoelectric ceramic speaker, it can convert electrical signals not only into audible sound waves but also into inaudible sound waves for purposes such as distance measurement. In some embodiments, audio circuit 307 may also include a headphone jack.

[0177] The positioning component 308 is used to determine the current geographic location of the terminal in order to enable navigation or LBS (Location Based Service). The positioning component 308 can be a positioning component based on the US GPS (Global Positioning System), China's BeiDou system, or Russia's Galileo system.

[0178] Power supply 309 is used to power the various components in the terminal. Power supply 309 can be AC ​​power, DC power, a disposable battery, or a rechargeable battery. When power supply 309 includes a rechargeable battery, the rechargeable battery can be a wired rechargeable battery or a wireless rechargeable battery. A wired rechargeable battery is a battery that is charged via a wired line, while a wireless rechargeable battery is a battery that is charged via a wireless coil. The rechargeable battery can also be used to support fast charging technology.

[0179] Those skilled in the art will understand that Figure 6 The structure shown does not constitute a limitation on the terminal and may include more or fewer components than shown, or combine certain components, or use different component arrangements.

[0180] Example 4

[0181] In an exemplary embodiment, a computer-readable storage medium is also provided, on which a computer program is stored, which, when executed by a processor, implements a maximum speed control method for an AGV device as provided in all embodiments of the present application.

[0182] Any combination of one or more computer-readable media may be used. A computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium can be, for example—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in connection with an instruction execution system, apparatus, or device.

[0183] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals may take various forms, including—but not limited to—electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, capable of transmitting, propagating, or transmitting programs for use by or in connection with an instruction execution system, apparatus, or device.

[0184] The program code contained on a computer-readable medium may be transmitted using any suitable medium, including—but not limited to—wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0185] Computer program code for performing the operations of this invention can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, as well as conventional procedural programming languages ​​such as "C" or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0186] Example 5

[0187] In an exemplary embodiment, an application product is also provided, including one or more instructions that can be executed by the processor 301 of the aforementioned device to complete the aforementioned AGV device maximum speed control method.

[0188] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for the invention. Further modifications can be readily made by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, the invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for controlling the maximum speed of an AGV device, characterized in that, Includes the following steps: Step 1: Obtain the cargo weight of the AGV vehicle; Step 2: Obtain the theoretical maximum speed V1 of the AGV based on the cargo mass and motor rated power of the AGV. Step 3: Obtain the maximum speed V2 of the AGV under safe conditions based on the cargo mass and maximum braking distance of the AGV; Step 4: Determine the maximum speed V of the AGV under the current load based on the theoretical maximum speed V1 and the maximum speed V2 of the AGV under safe conditions; Step 5: Use an encoder to obtain the current speed V of the AGV. n ; Step 6: Based on the current speed V of the AGV vehicle n Determine the speed difference ΔV based on the maximum speed V under the current load; Step 7: Perform PID control on the AGV based on the speed difference ΔV to stably control the AGV at its maximum speed.

2. The maximum speed control method for an AGV device according to claim 1, characterized in that, The specific method for step one is as follows: Use pressure sensors to obtain the weight of goods on the AGV (Automated Guided Vehicle). In the formula, m h The mass of goods carried by the AGV; m i The mass of the i-th pressure sensor is measured; V i V represents the voltage signal output by the i-th pressure sensor when it is subjected to pressure. max The full-scale output voltage of the pressure sensor; m max Let i be the full-scale mass of the pressure sensor; 1 ≤ i ≤ 4.

3. The maximum speed control method for an AGV device according to claim 1, characterized in that, The specific method for step two is as follows: Based on the mass m of the AGV trolley c The cargo mass m of the AGV cart h The total mass m of the AGV is obtained as shown in formula (3): m=m h +m c (3); The dynamics of the AGV are analyzed as shown in formula (4): F t =F f +F i +F w +F j (4); In the formula, F t For driving force; F f F represents rolling resistance. i For slope resistance; F w For air resistance; F j To increase resistance; Assuming the factory is on flat ground and the AGV has reached its maximum speed with zero acceleration resistance, ignoring air resistance, the equation can be simplified to formula (5): F t =F f (5); F f =m×g×f (6); In the formula, g is taken as 9.8 m / s 2 , where is the rolling resistance coefficient; The total rated power of the AGV trolley motor is calculated as shown in formula (7): P=k×P k (7); In the formula, P is the total rated power of the AGV trolley motors; k is the number of AGV trolley motors; P k The rated power of a single motor in the AGV (Automated Guided Vehicle) trolley; The theoretical maximum speed V1 of the AGV is calculated as shown in formula (8): Therefore 4. The maximum speed control method for an AGV device according to claim 1, characterized in that, The specific method for step three is as follows: The maximum speed V2 of the AGV under safe conditions is calculated by the maximum braking distance of the AGV, as shown in formula (10): In the formula, θ is the rotation angle of the brake pad at the maximum braking distance; S is the maximum braking distance; and R is the tire radius. The energy absorbed by the brake pads at the maximum braking distance is calculated as shown in formula (11): E=P s ×T=M×W×T=M×θ (11); In the formula, E is the energy absorbed by the brake pads at the maximum braking distance; P s Where M is the braking power; T is the braking time; M is the braking torque of the brake; W is the angular velocity of the brake pads. The maximum speed V2 of the AGV under safe conditions is calculated as shown in formula (12): Therefore 5. The maximum speed control method for an AGV device according to claim 1, characterized in that, The specific method for step four is as follows: Compare the theoretical maximum speed V1 of the AGV and the maximum speed V2 of the AGV under safe conditions, and take the minimum value as the maximum speed V of the AGV under the current load, as shown in formula (14): V = min(V1, V2) (14).

6. The maximum speed control method for an AGV device according to claim 1, characterized in that, The specific method for step five is as follows: The AGV trolley motor speed n is calculated as shown in formula (15): In the formula, x is the number of pulses output by the encoder within 1 second; X is the encoder resolution; Calculate the current speed V of the AGV based on the motor speed n of the AGV. n As shown in formula (16): In the formula, r is the rolling radius of the drive wheel; i0 is the transmission ratio of the transmission system.

7. The maximum speed control method for an AGV device according to claim 1, characterized in that, The specific method for step six is ​​as follows: △V=VV n (17) 8. The maximum speed control method for an AGV device according to claim 1, characterized in that, The specific method for step seven is as follows: The speed difference ΔV is input into the PID controller, and the speed control change is obtained through a preset PID algorithm, i.e.: In the formula, u(t) is the output of the PID controller; e(t) is the input of the PID controller, i.e., the deviation signal between the given value and the output value of the controlled object; K p T is the proportionality coefficient; i T is the integration time constant; d Let be the differential time constant; discretize equation (18) as shown in equation (19): Based on the incremental PID control principle, and using the AGV speed signal collected during the AGV's movement, the change in AGV speed control at time n is calculated as ΔV(n), as shown in formula (20): △V(n)=K p [V(n)-V(n-1)]+K i V(n)+K d [V(n)-2V(n-1)+V(n-2)] (20); In the formula, The integral coefficient; These are the differential coefficients; Therefore, the speed command V output by the PID controller at time n is obtained. s (n), as shown in formula (21): V s (n)=V s (n-1)+K p [V(n)-V(n-1)]+K i V(n)+K d [V(n)-2V(n-1)+V(n-2)] (1)。 9. A maximum speed control device for an AGV (Automated Guided Vehicle) unit, characterized in that, include: The acquisition module is used to obtain the weight of the goods carried by the AGV. The first calculation module is used to obtain the theoretical maximum speed V1 of the AGV based on the cargo mass and motor rated power of the AGV. The second calculation module is used to obtain the maximum speed V2 of the AGV under safe conditions based on the cargo mass and maximum braking distance of the AGV. The third calculation module is used to determine the maximum speed V of the AGV under the current load based on the theoretical maximum speed V1 of the AGV and the maximum speed V2 of the AGV under safe conditions. The fourth calculation module is used to obtain the current speed V of the AGV using an encoder. n ; The fifth calculation module is used to calculate the current speed V of the AGV. n Determine the speed difference ΔV based on the maximum speed V under the current load; The control module is used to perform PID control on the AGV based on the speed difference ΔV to stably control the AGV at its maximum speed.

10. A terminal, characterized in that, include: One or more processors; Memory for storing the one or more processor-executable instructions; Wherein, the one or more processors are configured as follows: Perform the maximum speed control method for an AGV device as described in any one of claims 1 to 8.

11. A non-transitory computer-readable storage medium, characterized in that, When the instructions in the storage medium are executed by the terminal's processor, the terminal is able to perform a maximum speed control method for an AGV device as described in any one of claims 1 to 8.

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