CN117872966A - Method for controlling the travel of an automatic guided vehicle, automatic guided vehicle and system - Google Patents
Method for controlling the travel of an automatic guided vehicle, automatic guided vehicle and system Download PDFInfo
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Abstract
The application relates to the field of control of automatic guided vehicles, and discloses a method for controlling running of an automatic guided vehicle, the automatic guided vehicle and a system, wherein the method comprises the following steps: acquiring a calibration mark, and adjusting the automatic guiding vehicle according to error data between the calibration mark and the automatic guiding vehicle to enable the error data between the automatic guiding vehicle and the calibration mark to be smaller than a calibration error threshold value; acquiring a navigation mark, and determining error data between an automatic guided vehicle and the navigation mark; determining the sideslip angular acceleration of the automatic guided vehicle according to the operation data, the parameter data, the error data and the preset motion model of the automatic guided vehicle; determining the total distance between the automatic guided vehicle and the end position according to the navigation mark; and controlling the automatic guided vehicle to run according to the sideslip angular acceleration, the total distance, the running data and the error data. The sideslip angular acceleration of the automatic guided vehicle is determined by using a preset motion model, so that the accurate sideslip angular acceleration can be obtained, the control precision of the automatic guided vehicle is improved, and the robustness is high.
Description
Technical Field
The present application relates to the field of control of automatic guided vehicles, and in particular to a method, an automatic guided vehicle, and a system for controlling the travel of an automatic guided vehicle.
Background
Since automatic guided vehicles (Automated Guided Vehicle, AGVs) have the characteristics of convenience, low cost, and high efficiency, AGVs are currently widely used in industry. The type, size, weight, and flexibility of the AGV will vary widely depending on the application. In situations where rapid transport of goods is required, AGVs are more concerned with flexibility and speed; in large warehouses where various loads are to be handled, there are more AGVs of greater weight and bulk.
While the AGV is in operation, the wheels may slip, creating lateral misalignment, causing the AGV to deviate from its target travel track. However, the degree of lateral offset of the AGV is affected by the change in conditions such as the slip angle, the distribution of the load, the driving force, the braking force, etc. of the AGV, so that the degree of lateral offset of the AGV is difficult to control in the case of running the AGV.
In view of the foregoing, it is desirable to provide a method, an automatic guided vehicle, and a system for controlling travel of an automatic guided vehicle that are capable of accurately controlling lateral offset of an AGV and are robust.
Disclosure of Invention
To solve the above problems, the present application proposes a method, an automatic guided vehicle and a system for controlling the travel of an automatic guided vehicle.
In one aspect, the present application proposes a method for controlling the travel of an automatic guided vehicle, comprising:
acquiring a calibration mark, and adjusting the automatic guide vehicle according to error data between the calibration mark and the automatic guide vehicle to enable the error data between the automatic guide vehicle and the calibration mark to be smaller than a calibration error threshold;
acquiring a navigation mark, and determining error data between the automatic guided vehicle and the navigation mark;
determining the sideslip angular acceleration of the automatic guided vehicle according to the operation data, the parameter data, the error data and a preset motion model of the automatic guided vehicle;
determining the total distance between the automatic guided vehicle and the end position according to the navigation mark;
and controlling the automatic guided vehicle to run according to the sideslip angular acceleration, the total distance, the running data and the error data.
Preferably, the method comprises the steps of,
the operation data includes a travel speed;
the parameter data includes: the width of the vehicle body, the distance from the center of the vehicle body structure to the mass center, the cornering stiffness of wheels on two sides of the vehicle body and the rotational inertia of the vehicle body;
the error data includes: transverse error, longitudinal error and orientation angle;
the sideslip angular acceleration is determined according to the running speed, the width of the vehicle body, the distance from the center of the vehicle body structure to the mass center, the cornering stiffness of wheels on two sides of the vehicle body, the rotational inertia of the vehicle body, the transverse error and the preset motion model;
and the preset motion model is determined according to the running information, the parameter information and the position information of the automatic guided vehicle.
Preferably, the acquiring the calibration mark, adjusting the automatic guided vehicle according to the error data between the calibration mark and the automatic guided vehicle, so that the error data between the automatic guided vehicle and the calibration mark is smaller than a calibration error threshold value, includes:
acquiring a calibration mark, and determining the error data between the automatic guided vehicle and the calibration mark;
and if the error data is greater than or equal to the calibration error threshold, adjusting the position and the orientation of the automatic guided vehicle according to the error data, continuously executing the step of acquiring the calibration mark, and determining the error data between the automatic guided vehicle and the calibration mark until the error data is smaller than the calibration error threshold.
Preferably, the obtaining the navigation identifier, determining error data between the automatic guided vehicle of the guided vehicle and the navigation identifier, includes:
shooting an image of the navigation mark, and acquiring a first position in the navigation mark;
determining a second position of the automatic guided vehicle according to the position of the navigation mark in the image;
and determining the error data between the automatic guided vehicle and the navigation mark according to the first position and the second position.
Preferably, the determining the total distance between the automatic guided vehicle and the end point position according to the navigation mark includes:
acquiring the end position in the navigation mark;
and determining the total distance according to the longitudinal error, the first position and the end position.
Preferably, the controlling the automatic guided vehicle to travel according to the sideslip angular acceleration, the total distance, the running data, and the error data includes:
determining the running speed of the automatic guided vehicle by using trapezoidal waves according to the total distance;
and controlling the running direction of the automatic guided vehicle by using proportional integral derivative according to the side slip angular acceleration and the running speed.
Preferably, after said controlling the traveling of the automatic guided vehicle according to the side slip angular acceleration, the total distance, the running data, and the error data, further comprises:
and continuously executing the step of acquiring the navigation mark, determining error data between the automatic guided vehicle and the navigation mark, updating the error data and the running data, determining new sideslip angular acceleration and new total distance, and controlling the automatic guided vehicle to run according to the new sideslip angular acceleration, the new total distance, the new running data and the updated error data until the automatic guided vehicle reaches the end position.
In a second aspect, the present application proposes an automatic guided vehicle comprising a camera device and two driving wheels, said driving wheels being located on both sides of said automatic guided vehicle, said automatic guided vehicle performing a method for controlling the running of the automatic guided vehicle as described above.
In a third aspect, the present application proposes a system for automated guided vehicle travel, comprising: navigation markers and auto guided vehicles as described above.
Preferably, the navigation mark comprises a two-dimensional code, and the two-dimensional code comprises position coordinates of the two-dimensional code and position coordinates of the two-dimensional code at the end point.
The application has the advantages that: calibrating the automatic guided vehicle through the calibration mark, so that error data between the automatic guided vehicle and the calibration mark is smaller than a calibration error threshold value, and thus, errors generated when the automatic guided vehicle runs are reduced; the method comprises the steps of substituting the obtained error data between the automatic guided vehicle and the navigation mark, the obtained parameter data and the obtained operation data of the automatic guided vehicle into a preset motion model to determine the sideslip angular acceleration of the automatic guided vehicle, and accurately analyzing the transverse stress of the automatic guided vehicle in the current driving state to obtain the accurate sideslip angular acceleration, so that the control precision of the automatic guided vehicle is improved, and the robustness is strong.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for the purpose of illustrating preferred embodiments and are not to be construed as limiting the application. Also, like reference numerals are used to designate like parts throughout the figures. In the drawings:
FIG. 1 is a schematic illustration of steps of a method for controlling travel of an automated guided vehicle provided herein;
FIG. 2 is a schematic illustration of a lateral force analysis of a method for controlling the travel of an automated guided vehicle provided herein;
FIG. 3 is a schematic illustration of a flow of a method for controlling travel of an automated guided vehicle provided herein;
FIG. 4 is a schematic illustration of navigation markers versus total distance for a method for controlling auto guided vehicle travel provided herein;
FIG. 5 is a schematic view of a trapezoidal wave of a method for controlling the travel of an automated guided vehicle provided herein;
fig. 6 is a schematic diagram of PID control of a method for controlling the travel of an automated guided vehicle provided herein.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
According to an embodiment of the present application, a method for controlling traveling of an automatic guided vehicle is provided, as shown in fig. 1, including:
s101, acquiring a calibration mark, and adjusting the automatic guiding vehicle according to error data between the calibration mark and the automatic guiding vehicle to enable the error data between the automatic guiding vehicle and the calibration mark to be smaller than a calibration error threshold;
s102, acquiring a navigation mark, and determining error data between an automatic guided vehicle and the navigation mark;
s103, determining the sideslip angular acceleration of the automatic guided vehicle according to the operation data, the parameter data, the error data and the preset motion model of the automatic guided vehicle;
s104, determining the total distance between the automatic guided vehicle and the end position according to the navigation mark;
s105, controlling the automatic guided vehicle to run according to the side slip angular acceleration, the total distance, the running data and the error data.
Further, the operation data includes a travel speed; the parameter data includes: the width of the vehicle body, the distance from the center of the vehicle body structure to the mass center, the cornering stiffness of wheels on two sides of the vehicle body and the rotational inertia of the vehicle body; the error data includes: transverse error, longitudinal error and orientation angle; the sideslip angular acceleration is determined according to the running speed, the width of the vehicle body, the distance from the center of the vehicle body structure to the mass center, the cornering stiffness of wheels on two sides of the vehicle body, the rotational inertia of the vehicle body, the transverse error and a preset motion model; the preset motion model is determined according to the running information, the parameter information and the position information of the automatic guided vehicle.
The operation information is an upper concept of operation data, and the operation information may be an empty set, or may include operation data, such as data, numerical value, etc., of the operation state of the automatic guided vehicle, which is specifically used for maintaining the basic operation of the automatic guided vehicle. The travel speeds include a left wheel travel linear speed and a right wheel travel linear speed of the automatic guided vehicle. The parameter information is an upper concept of parameter data, and the parameter information may be an empty set or may include specific parameter data, such as specific vehicle width data, numerical values, and the like. The position information is a generic concept of position and error data, and the position includes a first position, a second position, an end position, and the like. The position information may be an empty set, and may also include specific position and/or error data, such as specific orientation angle data, numerical values, and the like. The direction included angle is the included angle between the direction of the automatic guided vehicle and the X axis in the navigation mark or the calibration mark, the X axis is the longitudinal direction, the movement (running) direction of the automatic guided vehicle is the longitudinal direction, and the left-right deviation of the automatic guided vehicle is the transverse direction.
The preset motion model is a mathematical model built using the following equation:
wherein d is a differential (derivative) symbol, t is time, and y is a transverse error; θ is the angle of orientation, i.e. the angle of orientation of the automatic guided vehicle and the X axis; w is the width of the body of the automatic guiding vehicle, namely the width of the machine; v is the running speed of the automatic guided vehicle; k is the cornering stiffness of wheels on two sides of the body of the automatic guiding vehicle; k (k) L For the cornering stiffness, k of the left wheel of the body of the automatic guided vehicle R The lateral deflection rigidity of the right wheel of the automatic guiding vehicle body is that of the automatic guiding vehicle, and I is the rotational inertia of the vehicle body of the automatic guiding vehicle; n is the distance from the center of the body structure of the automatic guided vehicle to the center of mass.
Further, the method for acquiring the calibration mark, adjusting the automatic guided vehicle according to the error data between the calibration mark and the automatic guided vehicle, so that the error data between the automatic guided vehicle and the calibration mark is smaller than a calibration error threshold value, comprises the following steps: acquiring a calibration mark, and determining error data between the automatic guided vehicle and the calibration mark; if the error data is greater than or equal to the calibration error threshold, the position and the orientation of the automatic guided vehicle are adjusted according to the error data, the step of acquiring the calibration mark and determining the error data between the automatic guided vehicle and the calibration mark is continuously executed until the error data is smaller than the calibration error threshold. And under the condition that the error data is smaller than the calibration error threshold value, executing the step of acquiring the navigation mark and determining the error data between the automatic guided vehicle and the navigation mark.
The appearance and the form of the calibration mark are the same as those of the navigation mark, the difference between the calibration mark and the navigation mark is mainly different in application, and the calibration mark is used for prompting the automatic guided vehicle to calibrate. The automatic guiding vehicle can be adjusted according to the error data between the calibration mark and the automatic guiding vehicle only when the calibration mark is identified by the automatic guiding vehicle, so that the error data between the automatic guiding vehicle and the calibration mark is smaller than the calibration error threshold value. The error threshold is a preset transverse error threshold, a longitudinal error threshold and an orientation included angle threshold. Wherein the orientation angle threshold is 1 °.
Further, obtaining the navigation mark, determining error data between the automatic guided vehicle of the guided vehicle and the navigation mark, including: shooting an image of a navigation mark, and acquiring a first position in the navigation mark; determining a second position of the automatic guided vehicle according to the position of the navigation mark in the image; error data between the automated guided vehicle and the navigation mark is determined based on the first location and the second location.
Wherein the first position is an absolute position of the navigation mark in the global coordinate system. The second position of the automated guided vehicle may be determined based on the first position, the lateral error, and the longitudinal error.
Further, determining a total distance between the automated guided vehicle and the end position according to the navigation identifier includes: acquiring the end position in the navigation mark; and determining the total distance according to the longitudinal error, the first position and the end position.
The destination position is the destination position of the guide vehicle, and the total distance is the longitudinal distance between the guide vehicle and the destination position.
Further, controlling the automatic guided vehicle to travel according to the side slip angular acceleration, the total distance, the operation data and the error data, including: determining the running speed of the automatic guided vehicle by using trapezoidal waves according to the total distance; based on the side slip angular acceleration and the running speed, the running direction of the automatic guided vehicle is controlled using proportional-integral-derivative (Proport IntegralDifferential, PID).
Further, after controlling the traveling of the automatic guided vehicle according to the side slip angular acceleration, the total distance, the operation data, and the error data, the method further includes: and continuously executing the steps of acquiring the navigation mark, determining error data between the automatic guided vehicle and the navigation mark, updating the error data and the operation data, determining new sideslip angular acceleration and new total distance, and controlling the automatic guided vehicle to run according to the new sideslip angular acceleration, the new total distance, the new operation data and the updated error data until the automatic guided vehicle reaches the end position.
Every time the automatic guided vehicle acquires the navigation mark or the calibration mark, all data included in the navigation mark or the calibration mark, such as the first position, is refreshed (updated), and the second position and error data are corrected and updated.
Next, a preset motion model according to an embodiment of the present application will be further described with reference to fig. 2.
During running, the automatic guided vehicle receives driving force, braking force and rolling resistance. In addition, due to the reasons of deformation of the tire, uneven ground and the like, the wheels of the automatic guided vehicle can sideslip under the condition of running, so that transverse force is generated, and the transverse force exists for a long time. Therefore, when the traveling direction of the automatic guided vehicle makes an angle with the tire advancing direction, a force perpendicular to the tire rotation plane will be generated. This is also an important cause of reduced accuracy and stability in long-term operation of the automatic guided vehicle.
A two-wheel drive structure commonly used for automatic guided vehicles is: two driving wheels are arranged on two sides of the automatic guiding vehicle, and a plurality of auxiliary wheels with supporting function are arranged at other positions, wherein the driving wheels control the speed and the movement direction of the automatic guiding vehicle, and the functions are usually completed through a differential mechanism. Thus, the transverse forces are also mainly generated in the driving wheels on both sides of the automatic guided vehicle.
Lateral forces are very important forces that the vehicle must rely on for independent movement. The lateral force can be influenced by the change of the conditions such as the slip angle, the industry load distribution, the driving force, the braking force and the like of the automatic guided vehicle. According to the motion property of the automatic guided vehicle with the double-wheel chassis, the influence of differential motion of the left wheel and the right wheel on the running of the automatic guided vehicle can be determined, and the motion process of the automatic guided vehicle is analyzed by combining the side slip generated in the motion process of the automatic guided vehicle and the influence of transverse force, so that a preset motion model is established.
Firstly, the stress condition of the automatic guided vehicle is carefully analyzed, friction generated between the tire and the ground and generated transverse force are analyzed when the AGV runs, and available basic parameters of the automatic guided vehicle are determined and used as a part of parameter information. Before the transverse force is analyzed, the motion (running) direction of the automatic guided vehicle is defined as the longitudinal direction, the left-right deviation of the motion is defined as the transverse direction, and the meaning of letters appearing in fig. 2 and the formulas is explained, wherein y is the transverse error generated in the running of the automatic guided vehicle; θ is an included angle between the direction of the automatic guiding vehicle and the X axis, namely the angle deviation of the automatic guiding vehicle during operation; gamma is the included angle between the running direction of the guide vehicle and the X axis; w is the width of the body of the automatic guiding vehicle, namely the width of the machine; v is the running speed of the automatic guided vehicle; k is the cornering stiffness of wheels on two sides of the body of the automatic guiding vehicle; i is the rotational inertia of the body of the automatic guiding vehicle; beta is the sideslip angle; f is the transverse force acting on the tires on both sides of the automatic guided vehicle; m is the mass of the automatic guiding vehicle; n is the distance from the center of the body structure of the automatic guided vehicle to the mass center, and P is the center position of the automatic guided vehicle and the position of the camera device.
First, it is necessary to determine the equation of motion for the differential motion of the two wheels of the automated guided vehicle as follows:
wherein v is L Is the differential motion speed of the left wheel, v R The differential motion speed of the right wheel is represented by d, d is a differential symbol, and t is time.
Secondly, according to the general running condition of the automatic guiding vehicle, namely, the condition that gamma is less than 1 DEG, calculating the included angle gamma between the running direction of the tyre of the automatic guiding vehicle and the X axis, wherein the included angle gamma is as follows:
wherein, gamma L Is the included angle between the running direction of the left tyre of the automatic guiding vehicle and the X axis, gamma R The tan is tangent to the included angle between the running direction of the left tyre of the automatic guiding vehicle and the X axis.
In case γ < 1 °, the above equation can be simplified as:
since γ is 1 °, θ is 1 °.
From the above equation, the slip angle generated by the tires of the automatic guided vehicle during movement can be determined as follows:
wherein beta is L For the sideslip angle, beta, of the left tyre of the automatic guided vehicle R Is the sideslip angle of the tire on the right side of the automatic guiding vehicle.
Then, under the condition that the tire generates the sideslip angle during movement of the automatic guiding vehicle, the received transverse force is determined, namely, the sideslip angle is converted into the transverse force received by the automatic guiding vehicle, and the transverse force is as follows:
F L ＝-k L ·β L
F R ＝-k R ·β R
wherein F is L For lateral forces acting on the left tyre of the self-guided vehicle, k L For the cornering stiffness of the left wheel of the automatic guiding vehicle body, F R For lateral forces acting on the right-hand tyre of the automatic guided vehicle, k R Is used for automatically guiding the cornering stiffness of the right wheel of the vehicle body.
The effect of this force on the speed of the left and right tires of the automatic guided vehicle is analyzed based on the lateral forces that occur. Specifically, according to newton's second law, the acceleration is combined with the lateral force to obtain a velocity representing the change in θ as shown below:
and finally, analyzing the transverse deviation of the motion of the automatic guided vehicle caused by the tire speed difference, and establishing a mathematical model as a preset motion model. Specifically, according to the law of rotation, the angular acceleration is combined with the lateral force to obtain an equation representing the varying acceleration of θ as a preset motion model for calculating the side slip angular acceleration of the automatic guided vehicle, as follows:
the preset motion model of the application is established based on detailed analysis of the specific situation of the transverse force to which the automatic guided vehicle is subjected. According to the embodiment of the application, the preset motion model of the transverse force is included, so that the running error of the automatic guide vehicle caused by the transverse force can be compensated, and the subsequent control method is simpler and more convenient.
An embodiment of the present application will be further described with reference to fig. 3.
As shown in fig. 3, the automatic guided vehicle first acquires the calibration mark through the camera device installed therein, and determines the second position of the automatic guided vehicle according to the first position of the current calibration mark in the calibration mark and the reference lines (horizontal reference line and vertical reference line) of the calibration mark. And determining an included angle theta between the orientation of the automatic guided vehicle and the X axis, and a longitudinal error and a transverse error between the second position and the first position according to the obtained first position and second position. Then, it is determined whether the error data is less than a calibration error threshold. If the difference data is greater than or equal to the calibration error threshold, the second position and the orientation of the automatic guided vehicle are adjusted according to the error data, the calibration mark is continuously acquired, the error data between the automatic guided vehicle and the calibration mark is determined, whether the newly obtained error data is smaller than the calibration error threshold is judged, and the automatic guided vehicle can travel to the navigation mark or the end position according to the navigation mark or the end position included in the calibration mark until the newly obtained error data is smaller than the calibration error threshold. And (3) a navigation mark exists on the driving path of the automatic guided vehicle, and the automatic guided vehicle circularly executes the steps of acquiring the navigation mark and determining error data between the automatic guided vehicle and the navigation mark in the driving process. In the process of driving the automatic guided vehicle from the calibration mark to the navigation mark, the automatic guided vehicle can drive according to the preset speed, and the sideslip angular acceleration of the automatic guided vehicle of the guided vehicle can be determined by using error data, operation data, parameter data and a preset motion model which are acquired at the calibration mark; and controlling the automatic guided vehicle to travel to the final position or the navigation mark based on the sideslip angle acceleration, the total distance, the running data and the error data according to the total distance between the automatic guided vehicle and the final position or taking the distance between the automatic guided vehicle and the navigation mark as the total distance. If the distance between the automatic guided vehicle and the navigation mark is used as the total distance, the total distance is updated according to the end position in the navigation mark after the automatic guided vehicle acquires the navigation mark.
As shown in fig. 4, the automatic guided vehicle shoots an image of the navigation mark, acquires a first position in the navigation mark, and a reference line of the navigation mark, and determines a second position of the automatic guided vehicle. And determining an included angle theta between the orientation of the automatic guided vehicle and the X axis, and a longitudinal error and a transverse error between the second position and the first position according to the obtained first position and second position. And determining the sideslip angular acceleration of the automatic guided vehicle according to the running data, the parameter data, the error data and the preset motion model of the automatic guided vehicle. And determining the total distance between the automatic guided vehicle and the destination according to the navigation mark. As shown in fig. 4, taking the first position of the navigation mark Q4 as the end position as an example, Δx marks the longitudinal error, dis, between the camera device of the automatic guided vehicle and the first position of the navigation mark X Indicating the distance between the first position and the end position, dis T Indicating the total distance between the automatic guided vehicle and the end position, i.e. Dis T ＝Δx+Dis X . Then, according to the total distance, determining the running speed of the automatic guided vehicle by using the trapezoidal wave; in the process of controlling the running speed of the automatic guided vehicle by using the trapezoidal wave, a control signal is outputted by using proportional integral derivative control according to the side slip angular acceleration and the running speed, and the running direction of the automatic guided vehicle is controlled. Wherein the first position in the navigation mark is the absolute position of the navigation mark in the global coordinate system, as shown in fig. 4, if the region contained in fig. 4 is regarded as the global coordinate system and the first position of the navigation mark Q1 is (10, 10), the first position of the navigation mark Q2 is (10+Δxq2, 10), and the first position of the navigation mark Q3 is (10+Δq 2)xq2+Δxq3, 10), the first position of the navigation mark Q4 is (10+Δxq2+Δxq3+Δxq4, 10).
As shown in fig. 5, a schematic drawing of a trapezoidal wave is drawn according to the length of the total distance. For controlling the longitudinal error, a trapezoidal wave is used for planning the track of the automatic guided vehicle, under the condition of given speed, acceleration and acceleration rate of the automatic guided vehicle, the trapezoidal wave is drawn according to the length of the total distance, the speed and acceleration corresponding to time are determined, and when the navigation mark is identified each time, the speed, the acceleration rate and the total distance of the automatic guided vehicle are updated, and a new trapezoidal wave is drawn.
For control of the lateral error, PID control is used to adjust the actual value of the lateral error determined by the image pickup device from the navigation mark. If the target value in the PID control is 0, no lateral error is indicated. The actual value and the target value are obtained by PID feedback, respectively. The control input signal is obtained by a PID controller in the automatic guided vehicle, and the accurate advancing direction of the automatic guided vehicle can be finally determined. From the PID control, the following equation can be determined:
δ＝θ+u
where δ represents the direction of travel of the automatic guided vehicle after correction, θ represents the direction of travel of the automatic guided vehicle before correction, and u represents the control signal of the PID. From the above equation, a PID control equation for controlling the automatic guided vehicle by PID can be determined as follows:
θ＝δ-u
as shown in fig. 6, there is a schematic diagram of adjusting the actual value of the lateral error by controlling the speeds of the two driving wheels on both sides of the automatic guided vehicle through the PID controller. The target value corresponds to the transverse error, the output value corresponds to the adjusted transverse error, the speed error e of the two wheels is adjusted in real time according to the output value, and the speed error e of the whole two wheels is obtained by subtracting the output value from the target value; and a PID controller is used for outputting a control signal u according to the speed error e, the speeds of the two driving wheels are controlled through the control signal u according to a motion equation of differential motion of the two wheels, so that the transverse error y of the automatic guided vehicle is adjusted, the speed error e is determined to be continuously determined according to the adjusted transverse error y, and the transverse error of the automatic guided vehicle is continuously adjusted. Until the target value is 0. And finally, connecting an error control strategy with the operation process of the automatic guided vehicle by combining the PID control equation with a preset motion model, so as to accurately and stably control the operation of the automatic guided vehicle.
In a second aspect, according to an embodiment of the present application, there is also provided an automatic guided vehicle including an image pickup device and two driving wheels, the driving wheels being located on both sides of the automatic guided vehicle, the automatic guided vehicle performing the above-described method for controlling the running of the automatic guided vehicle.
Wherein, camera device can include industry camera, and automatic guided vehicle still includes control module. And identifying the navigation mark through the camera device to obtain the running information and the position information of the automatic guided vehicle. Specifically, the image pickup device may be installed at any position of the automatic guided vehicle, but is optimally installed at the center position of the automatic guided vehicle, and the current position of the automatic guided vehicle may be more accurately recognized. The image pickup device acquires navigation marks on the running (traveling) path of the automatic guided vehicle at a fixed frequency. The navigation mark may be disposed on or above the ground of the travel path. And the current position information and error data of the automatic guided vehicle are obtained by identifying the currently acquired navigation mark, and are analyzed and processed by a control module of the automatic guided vehicle.
The automated guided vehicle may further include: the motor comprises an electric drive, an alternating current motor, a speed reduction wheel and a plurality of universal wheels.
In a third aspect, the present application proposes a system for automated guided vehicle travel, comprising: navigation markers and auto guided vehicles as described above.
Further, the navigation mark comprises a two-dimensional code, and the two-dimensional code comprises position coordinates of the two-dimensional code and position coordinates of the two-dimensional code at the end point.
The device further comprises a calibration mark, wherein the calibration mark comprises a two-dimensional code. The structure of the two-dimensional code comprises: a central two-dimensional code diagram, a horizontal reference line, a vertical reference line, an identification area mark, a peripheral reference line, a serial number and the like. The content in the two-dimensional code comprises: two-dimensional code data, two-dimensional code angles, algorithm time (time information or data required by the calculation of a preset motion model), time stamps and other information. Under the running condition of the automatic guiding vehicle, the orientation included angle can be determined by means of the horizontal reference line and the vertical reference line, and the longitudinal error and the transverse error are obtained according to the content in the two-dimensional code. The identification area identification can help an industrial camera installed on the automatic guide vehicle to identify a navigation area corresponding to the two-dimensional code, so that error values can be fed back more quickly and accurately. The peripheral reference line can help the user to accurately place the two-dimensional code. The serial number is used for uniquely identifying the two-dimensional code. The serial number should be unique and not repeatable throughout the navigation area.
Further, the two-dimensional code is arranged below the driving route of the automatic guide vehicle and at the centers of two sides of the driving route, so that the information in the two-dimensional code can be conveniently acquired by the camera device. The sampling frequency of the camera may be 100Hz. Under the condition that the automatic guiding vehicle sideslips, the camera device is driven to rotate by a certain rated angle, and therefore, the included angle between the automatic guiding vehicle and the two-dimensional code reference line is an orientation included angle corresponding to the sideslip angle generated by the automatic guiding vehicle.
The two-dimensional code is used as a navigation mark and a calibration mark, so that the navigation mode can be greatly simplified, the navigation precision is improved, and the navigation cost of the automatic guided vehicle during operation can be obviously reduced. Through the navigation mark and the calibration mark, the automatic guided vehicle can optimize the operation of the automatic guided vehicle, so that the stability of the automatic guided vehicle is improved, the robustness of the automatic guided vehicle to various operation environments is improved, and the automatic guided vehicle can operate with high precision for a long time.
According to the method, the transverse force applied to the automatic guided vehicle is analyzed based on the automatic guided vehicle with the double-wheel chassis, a mathematical model is established as a preset motion model, and based on the mathematical model, the position information and the error data which are quickly acquired by the navigation mark are combined to determine the sideslip angular acceleration of the automatic guided vehicle, so that under the condition that the automatic guided vehicle operates, the transverse force applied to the automatic guided vehicle in the motion process can be quickly and accurately described, and the accuracy and the robustness for controlling the operation of the automatic guided vehicle are improved; longitudinal error control is performed through trapezoidal waves, and transverse errors are controlled by combining PID, so that more accurate, more stable and more robust control and navigation can be provided for the running of the automatic guided vehicle, and the navigation identification cost required by the control method is low, so that the control method can be applied to various scenes in a large quantity and conveniently, and the running accuracy, stability and robustness of the automatic guided vehicle are improved. Meanwhile, the control method has lower requirement on hardware of the automatic guide vehicle, and can greatly reduce the hardware cost and subsequent maintenance cost of the automatic guide vehicle, thereby reducing the overall operation cost of the automatic guide vehicle applied to various businesses and ensuring the safety and reliability of operation.
The foregoing is merely a preferred embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions easily contemplated by those skilled in the art within the technical scope of the present application should be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
Claims (10)
1. A method for controlling travel of an automated guided vehicle, comprising:
acquiring a calibration mark, and adjusting the automatic guide vehicle according to error data between the calibration mark and the automatic guide vehicle to enable the error data between the automatic guide vehicle and the calibration mark to be smaller than a calibration error threshold;
acquiring a navigation mark, and determining error data between the automatic guided vehicle and the navigation mark;
determining the sideslip angular acceleration of the automatic guided vehicle according to the operation data, the parameter data, the error data and a preset motion model of the automatic guided vehicle;
determining the total distance between the automatic guided vehicle and the end position according to the navigation mark;
and controlling the automatic guided vehicle to run according to the sideslip angular acceleration, the total distance, the running data and the error data.
2. The method of claim 1, wherein,
the operation data includes a travel speed;
the parameter data includes: the width of the vehicle body, the distance from the center of the vehicle body structure to the mass center, the cornering stiffness of wheels on two sides of the vehicle body and the rotational inertia of the vehicle body;
the error data includes: transverse error, longitudinal error and orientation angle;
the sideslip angular acceleration is determined according to the running speed, the width of the vehicle body, the distance from the center of the vehicle body structure to the mass center, the cornering stiffness of wheels on two sides of the vehicle body, the rotational inertia of the vehicle body, the transverse error and the preset motion model;
and the preset motion model is determined according to the running information, the parameter information and the position information of the automatic guided vehicle.
3. The method of claim 2, wherein the obtaining the calibration mark, adjusting the automated guided vehicle based on error data between the calibration mark and the automated guided vehicle such that the error data between the automated guided vehicle and the calibration mark is less than a calibration error threshold, comprises:
acquiring a calibration mark, and determining the error data between the automatic guided vehicle and the calibration mark;
and if the error data is greater than or equal to the calibration error threshold, adjusting the position and the orientation of the automatic guided vehicle according to the error data, continuously executing the step of acquiring the calibration mark, and determining the error data between the automatic guided vehicle and the calibration mark until the error data is smaller than the calibration error threshold.
4. The method of claim 2, wherein the obtaining a navigation identifier, determining error data between the automated guided vehicle and the navigation identifier, comprises:
shooting an image of the navigation mark, and acquiring a first position in the navigation mark;
determining a second position of the automatic guided vehicle according to the position of the navigation mark in the image;
and determining the error data between the automatic guided vehicle and the navigation mark according to the first position and the second position.
5. The method of claim 2, wherein said determining a total distance between the automated guided vehicle and an end position based on the navigation identity comprises:
acquiring the end position in the navigation mark;
and determining the total distance according to the longitudinal error, the first position and the end position.
6. The method of claim 5, wherein said controlling said automated guided vehicle travel based on said side-slip angular acceleration, said total distance, said operational data, and said error data comprises:
determining the running speed of the automatic guided vehicle by using trapezoidal waves according to the total distance;
and controlling the running direction of the automatic guided vehicle by using proportional integral derivative according to the side slip angular acceleration and the running speed.
7. The method of claim 1, further comprising, after said controlling said automated guided vehicle to travel based on said side slip angular acceleration, said total distance, said operational data, and said error data:
and continuously executing the step of acquiring the navigation mark, determining error data between the automatic guided vehicle and the navigation mark, updating the error data and the running data, determining new sideslip angular acceleration and new total distance, and controlling the automatic guided vehicle to run according to the new sideslip angular acceleration, the new total distance, the new running data and the updated error data until the automatic guided vehicle reaches the end position.
8. An automatic guided vehicle comprising a camera device and two driving wheels, said driving wheels being located on both sides of said automatic guided vehicle, said automatic guided vehicle performing a method according to any one of claims 1-7.
9. A system for automated guided vehicle travel, comprising: navigation markers and the automated guided vehicle of claim 8.
10. The system of claim 9, wherein the navigation identifier comprises a two-dimensional code, the two-dimensional code comprising a position coordinate of the two-dimensional code and a position coordinate of the two-dimensional code at the end point.
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| CN202311650732.0A CN117872966A (en) | 2023-12-04 | 2023-12-04 | Method for controlling the travel of an automatic guided vehicle, automatic guided vehicle and system |
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| CN202311650732.0A CN117872966A (en) | 2023-12-04 | 2023-12-04 | Method for controlling the travel of an automatic guided vehicle, automatic guided vehicle and system |
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