An intelligent driving electric plant protection vehicle with adjustable height and wheelbase

Abstract

The present invention belongs to the technical field of agricultural machinery, and specifically relates to an intelligent driving electric plant protection operation vehicle with adjustable height and wheelbase, comprising a front frame, a rear frame, a folding steering mechanism, a wheelbase adjustment mechanism, a height adjustment mechanism and a spray rod mechanism; a medicine box, a diaphragm pump and a gantry are installed on the rear frame, and the wheelbase adjustment mechanism is arranged between the moving wheel and the frame; the height adjustment mechanism comprises a connecting seat, a U-shaped bolt and a wheel frame, and the spray rod mechanism comprises a lifting frame, side wheels, an electric push rod, a main spray rod and a side spray rod; side wheels are arranged on both sides of the lifting frame, and the side wheels are nested on tracks on both sides of the gantry; the main spray rod is fixed on the lifting frame, and the side spray rod is folded and arranged on the main spray rod, so that the present invention can be adaptively adjusted according to the row spacing and plant height of the operation, can be suitable for spraying during the whole period of plant protection, has strong versatility, and adopts remote control as the control method, thereby improving the intelligence level of plant protection operations.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural machinery, and in particular relates to an intelligent driving electric plant protection operation vehicle with adjustable height and wheelbase. Background Art

[0002] my country has a vast territory, rich agricultural environment, and diverse crop types. The agronomic requirements of crops such as wheat and soybeans are obviously differentiated. The row spacing is obvious, and the fixed wheelbase cannot achieve the universalization of agricultural machinery. As the crops grow, the plant height changes greatly. The height of traditional plant protection vehicles cannot be adjusted, so they can only travel between rows and cannot straddle the crops.

[0003] The driving power of existing agricultural machinery is generally engine-driven. As the capacity of batteries becomes larger and larger, batteries can be used as power for agricultural machinery. Compared with the transmission drive method, it has the advantages of light weight, energy saving and environmental protection. At the same time, the wheelbase and height of traditional agricultural machinery cannot be adjusted according to the growth of crops, and the versatility is poor.

[0004] The operation mode of existing agricultural machinery is generally to manually operate the steering wheel for steering and walking. This structure mostly relies on manpower, which wastes manpower, especially for severe working environments, such as hot weather, etc. People need to endure high temperature environments to work. The low intelligence brings trouble to people. At the same time, the height and wheelbase of existing agricultural machinery cannot be adaptively adjusted according to the height of the crops and the row spacing, which is inconvenient to use. Therefore, it is necessary to study an intelligent driving electric plant protection operation vehicle with adjustable height and wheelbase. Summary of the invention

[0005] In view of the defects and problems existing in the existing equipment, the present invention provides an intelligent driving electric plant protection operation vehicle with adjustable height and wheelbase, which effectively solves the problems existing in the existing equipment that the wheelbase and height cannot be adjusted and the intelligent driving mode of the agricultural machinery is low.

[0006] The solution adopted by the present invention to solve its technical problems is: an intelligent driving electric plant protection operation vehicle with adjustable height and wheelbase, comprising a front frame, a rear frame, a folding steering mechanism, a wheelbase adjustment mechanism, a height adjustment mechanism and a spray rod mechanism; the front frame and the rear frame are connected by the folding steering mechanism to form a frame body, a power supply and a remote control receiver are installed on the front frame, a medicine box, a diaphragm pump and a gantry are installed on the rear frame, and the wheelbase adjustment mechanism is arranged between the moving wheel and the frame; the height adjustment mechanism comprises a connecting seat, a U-shaped bolt and a wheel frame, the connecting seat is fixed on the frame, the U-shaped bolt passes through the connecting seat and fixes the wheel frame on the connecting seat, and a moving wheel is installed at the bottom of the wheel frame, and each moving wheel is installed with a driving motor; the folding steering mechanism comprises a steering motor, A front bogie, a rear bogie, a gear set and a drive shaft, wherein the front bogie and the rear bogie are respectively fixed at the joints of the front frame and the rear frame; the steering motor is installed on the rear bogie via a bracket, the front bogie is fixed on the drive shaft, and the rear bogie is rotatably arranged at both ends of the drive shaft; the steering motor is transmission-connected with the drive shaft via a gear set, so that the front bogie can rotate relative to the rear bogie under the drive of the steering motor; the spray rod mechanism comprises a lifting frame, side wheels, an electric push rod, a main spray rod and a side spray rod; side wheels are arranged on both sides of the lifting frame, and the side wheels are nested on the tracks on both sides of the gantry, and the electric push rod is arranged between the lifting frame and the gantry, and is used to drive the lifting frame to rise and fall along the gantry; the main spray rod is fixed on the lifting frame, and the side spray rod is folded and arranged on the main spray rod.

[0007] Furthermore, the gear set includes a driving gear, a driven gear, a sleeve gear and a driving gear; a driving gear is sleeved on the rotating shaft of the steering motor, the driving gear is meshed with the driven gear, the sleeve gear is coaxially sleeved on the lower part of the driven gear, and the driving gear is meshed with the sleeve gear; the lower part of the driving gear is fixedly sleeved on the upper part of the driving shaft.

[0008] Furthermore, a folding part is arranged between the two sides of the main spray boom and the side spray boom, and the folding part includes an upper cross plate, a lower cross bar, a middle axis, a holder and a baffle; the upper cross plate and the lower cross bar are respectively arranged at the upper and lower ends of the main spray boom in the horizontal direction, and the middle axis vertically penetrates the upper cross plate and the lower cross bar and can rotate; the holder has a trapezoidal structure, the holder is fixed on the middle axis, and its bottom is seated on the tubular lower cross bar, the baffle is located on the upper part of the middle axis, and the spring is sleeved on the middle axis and is located between the baffle and the holder.

[0009] Furthermore, the wheelbase adjustment mechanism includes an adjustment sleeve, an adjustment rod and a limit bolt; the adjustment sleeve is fixed on the front frame, the adjustment rod is sleeved in the adjustment sleeve, and the adjustment sleeve and the adjustment rod are respectively provided with a fixing hole and a plurality of positioning holes; the limit bolt is adjusted in the fixing hole and the positioning hole to maintain the position of the adjustment rod and the adjustment sleeve.

[0010] Furthermore, a slot is provided on the wheel frame, and a scale is marked on the slot accordingly, and the U-shaped bolt is matched with the sleeve in the slot.

[0011] Furthermore, it also includes a control system, which includes a sensor, a host computer, a controller, a diaphragm pump, a drive motor and a steering motor; the sensor is used to receive the vehicle condition information of the plant protection vehicle and upload it to the controller, the host computer sends instructions to the controller via the wireless module, the controller analyzes the vehicle condition information and instructions after receiving them, and adjusts the spray power, vehicle speed and steering of the plant protection vehicle by controlling the operation of the diaphragm pump, the drive motor and the steering motor.

[0012] Beneficial effects of the present invention: The present invention adopts a lightweight structural design and improves the driving mode to reduce soil compaction; the body design is adjustable to adapt to different crops such as wheat, corn and soybeans; the motor is used as the power source, and the battery is used as the power source to improve the intelligent control level of the machine; the work vehicle can be remotely controlled by a remote control, and after switching to the automatic mode, the path can be tracked according to the predetermined route to achieve autonomous walking of the work vehicle. The development of autonomous walking plant protection work vehicles can reduce the amount of pesticides and production costs, reduce operating hazards, and improve operating efficiency.

[0013] The work vehicle of the present invention adopts a solution with adjustable wheelbase and chassis ground clearance in structure and four-wheel drive in power, wherein the wheelbase adjustment structure is adjustable in the range of 1 to 1.3m, and the chassis ground clearance is designed to be adjustable in the range of 0.5 to 1.3m. The path tracking strategy is determined, and the stability of the steering control is analyzed by the Lyapunov function; in order to improve the control accuracy of the plant protection work vehicle, the extended Kalman filter algorithm of the sensor and the PID control method of the drive motor are proposed; the vehicle with waist-steering coordinated steering is more maneuverable and better than the sliding steering, ensuring that the plant protection vehicle can maintain the maximum thrust provided by the drive element during the turn;

[0014] The design width of the spray boom is 6m. The most reasonable size of the spray boom after folding is not much different from the wheelbase, which can better carry out the transfer operation. The multi-stage folding method is adopted. A structure that can be pressed and rotated is designed at the connection between the main spray boom and the side spray boom. The card seat is fixed on the middle axis and the card seat is on the lower cross bar. The baffle is located on the upper part of the middle axis. The spring is set on the middle axis and located between the baffle and the card seat. It is fixed with a trapezoidal groove. This structure can be easily folded or unfolded, while ensuring balance and stability during operation.

[0015] Therefore, the present invention provides a plant protection operation vehicle with adjustable wheelbase and height, which can be adaptively adjusted according to the row spacing and plant height of the operation, can be suitable for full-period spraying of plant protection, has strong versatility, is driven by a battery, and is equipped with a lightweight frame. The control method adopts remote control, which improves the intelligence level of plant protection operations, has a wide range of applications, is easy to operate, and saves manpower. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the present invention.

[0017] Figure 2 for Figure 1 main view.

[0018] Figure 3 for Figure 1 Front view of.

[0019] Figure 4 for Figure 1 Rear view of.

[0020] Figure 5 A schematic diagram of the frame structure.

[0021] Figure 6 for Figure 5 Top view of the .

[0022] Figure 7 for Figure 5 main view.

[0023] Figure 8 It is a schematic diagram of the structure of the folding part.

[0024] Fig. 9 It is a schematic diagram of the bending steering structure.

[0025] Fig.10 for Fig. 9 Another perspective of the picture.

[0026] Fig.11 Another structural schematic diagram of the wheelbase adjustment mechanism.

[0027] Fig.12 It is a schematic diagram of the frame structure of the control system.

[0028] Fig.13 This is a flowchart for posture acquisition.

[0029] Fig.14 This is a flow chart of path tracing.

[0030] Fig.15 This is the dynamic coordinate diagram of the walking system.

[0031] Fig.16is the error between the working vehicle and the target point in polar coordinates.

[0032] Fig.17 Schematic diagram of strapdown inertial navigation.

[0033] Fig.18 This is the block diagram of the PID controller.

[0034] Fig.19 It is the equivalent circuit of the motor armature.

[0035] Fig. 20 This is a schematic diagram of the dynamic structure of a DC motor.

[0036] The numbers in the figure are: 1 is the front frame, 2 is the rear frame, 3 is the bending steering mechanism, 31 is the steering motor, 32 is the driving gear, 33 is the driven gear, 34 is the set gear, 35 is the driving gear, 36 is the driving shaft, 37 is the front bogie, 38 is the rear bogie; 4 is the power supply, 5 is the remote control receiver, 6 is the medicine box, 7 is the gantry, 8 is the lifting frame, 9 is the side wheel, 10 is the main spray rod, 11 is the side spray rod, 12 is the adjustment sleeve, 13 is the adjustment rod, 14 is the connecting seat, 15 is the U-bolt, 16 is the wheel frame, 17 is the moving wheel, 18 is the upper cross plate, 19 is the lower cross bar, 20 is the middle shaft, 21 is the seat, 22 is the spring, 23 is the baffle; 24 is the rack, and 25 is the gear. DETAILED DESCRIPTION

[0037] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0038] Example 1: This example aims to provide an intelligent driving electric plant protection vehicle with adjustable height and wheelbase, which is mainly used in the field of plant protection. As crops grow, their plant height changes, and there are differences in row spacing between different crops. Traditional plant protection vehicles cannot be adjusted according to these changes, resulting in poor versatility. In addition, most operations are manually performed, and operators are exposed to harsh environments, which brings trouble to people. For this reason, this example provides a remote-controlled electric plant protection vehicle with adjustable frame height and wheelbase.

[0039] like Figure 1 As shown, a height- and wheelbase-adjustable intelligent driving electric plant protection operation vehicle comprises a front frame 1, a rear frame 2, a folding steering mechanism 3, a wheelbase adjustment mechanism, a height adjustment mechanism and a spray rod mechanism; the front frame 1 and the rear frame 2 are connected by the folding steering mechanism 3 to form a frame body, a power supply 4 and a remote control receiver 5 are installed on the front frame 1, and a medicine box 6, a diaphragm pump and a gantry 7 are installed on the rear frame 2. Since remote control is adopted in this embodiment, the frame does not need to bear the gravity of the engine and people. The frame is made of lightweight material and only needs to bear the gravity of the power supply and the medicine box, thereby reducing soil compaction and the overall dead weight of the plant protection vehicle, making it lighter and convenient for transportation, storage and deployment.

[0040] The wheelbase adjustment mechanism is arranged between the moving wheel 17 and the frame; the wheelbase adjustment mechanism includes an adjusting sleeve 12, an adjusting rod 13 and a limiting bolt; the adjusting sleeve 12 is fixed on the front frame 1, the adjusting rod 13 is sleeved in the adjusting sleeve 12, and the adjusting sleeve 13 and the adjusting rod 12 are respectively provided with a fixing hole and a plurality of positioning holes; the limiting bolt is adjusted in the fixing hole and the positioning hole to maintain the position of the adjusting rod and the adjusting sleeve. In this embodiment, the adjusting rod and the adjusting sleeve are both square tube structures, which will not rotate but can only slide relatively and have good stability. The adjusting sleeve can be a square tube and serve as the basic structure of the frame. The adjusting rod is sleeved on the end of the adjusting sleeve, and the adjusting rod and the adjusting sleeve are penetrated and fixed together by the limiting bolt.

[0041] The height adjustment mechanism includes a connecting seat 14, a U-shaped bolt 15 and a wheel frame 16. The connecting seat 14 is fixed to the end of the adjustment rod 13. Figure 1-4 As shown, the connecting seat 14 is vertically fixed to the outer end of the adjusting rod, the U-shaped bolt 15 passes through the connecting seat 14 and clamps the wheel frame 16 on the connecting seat 14, and a moving wheel 17 is installed at the bottom of the wheel frame 16, and each moving wheel is installed with a driving motor; by loosening the U-shaped bolt, the wheel frame can slide up and down relative to the connecting seat, and the height of the frame relative to the wheel frame can be adjusted. After the adjustment is in place, the U-shaped bolt can be tightened to complete the height adjustment of the frame relative to the plant at its bottom.

[0042] The bending steering mechanism 3 includes a steering motor 31, a front bogie 37, a rear bogie 38, a gear set and a drive shaft 36. The front bogie 37 and the rear bogie 38 are fixed at the joints of the front frame 1 and the rear frame 2 respectively; the steering motor 31 is installed on the rear bogie 38 via a bracket, the front bogie 37 is fixed on the drive shaft 36, and the rear bogie 38 is rotatably arranged at both ends of the drive shaft 36; the steering motor 31 is transmission-connected with the drive shaft 36 via a gear set, so that the front bogie can rotate relative to the rear bogie under the drive of the steering motor; the gear set includes a driving gear 32, a driven gear 33, a set gear 34 and a driving gear 35; a driving gear is set on the rotating shaft of the steering motor, the driving gear is meshed with the driven gear, the set gear is coaxially set on the lower part of the driven gear, and the driving gear is meshed with the set gear; the lower part of the driving gear is fixedly set on the upper part of the driving shaft.

[0043] In this embodiment, the steering motor 31 is connected to the gear set, and then the power is transmitted to the drive shaft 36. The rotation of the drive shaft causes the front bogie to rotate relative to the rear bogie. Therefore, the directional steering of the frame can be achieved through the speed and direction of the steering motor 31, providing equipment support for remote control steering.

[0044] The spray rod mechanism includes a lifting frame 8, side wheels 9, an electric push rod, a main spray rod 10 and a side spray rod 11; side wheels 9 are arranged on both sides of the lifting frame 8, and the side wheels 9 are nested on the tracks on both sides of the gantry 7. The electric push rod is arranged between the lifting frame and the gantry to drive the lifting frame to rise and fall along the gantry; the main spray rod 10 is fixed on the lifting frame 8, and the side spray rod 11 is folded and arranged on the main spray rod 10.

[0045] This embodiment also includes a control system, which includes a posture sensor, a host computer, a controller, a diaphragm pump, a drive motor and a steering motor; the posture sensor is used to receive the vehicle condition information of the plant protection vehicle and upload the vehicle condition information to the controller, the host computer sends instructions to the controller via the wireless module, and the signal output end of the controller adjusts the spray power, vehicle speed and steering of the plant protection vehicle by controlling the operation of the diaphragm pump, the drive motor and the steering motor.

[0046] Specifically, in this embodiment, Fig.12 As shown, the attitude sensor includes a magnetometer, a gyroscope and a GPS positioning module. The magnetometer, the gyroscope and the GPS positioning module perform Kalman filtering on the data, convert the matrix data of the attitude data (coordinate transformation), perform yaw correction, and calculate the yaw accumulation value to obtain the target throttle speed and target steering speed data:

[0047] 1. Matrix of vehicle motion model

[0048] Fig.15 O is the hinge point with motor-assisted steering; O1 and O2 are the centers of the front and rear axles respectively; φ is the steering angle; θ1 and θ2 are the azimuth angles of the front and rear frames; l1 is the length between the front frame hinge joint and the center of the front axle, l2 is the length between the rear frame hinge joint and the center of the rear axle, l1=l2; W is the frame wheelbase; C is the center of the platform rotation radius

[0049] In order to obtain the kinematic equation of the walking platform, several assumptions need to be made: the platform steering angle φ remains constant under small displacement conditions; the dynamic effect caused by low speed is ignored; and there is no slip effect when the walking platform moves on a plane.

[0050] The non-complete integral constraints of the front and rear frames can be expressed by the following formula:

[0051]

[0052]

[0053] The kinematic relationship between the steering angle φ and the azimuth angles of the front and rear frames can be expressed as

[0054]

[0055] The translational motion equation of the front frame can be expressed as:

[0056]

[0057]

[0058] The velocities v1 and v2 are considered to have the same change relative to the velocities of the rigid free joints of the vehicle, so the relative velocity vector equation can be defined as:

[0059]

[0060]

[0061] Combining (3), (6), and (7), we can get

[0062]

[0063]

[0064] angle and θ1 can be measured very accurately. Since the hinge is equipped with an auxiliary steering motor, there is a steering restriction on the rear drive. The relationship between the front frame and the rear frame can be expressed as:

[0065] x2=x1-l1 cosθ1-l2 cosθ2 (10)

[0066] y2=y1-l1 sinθ1-l2 sinθ2 (11)

[0067] In the proposed method, the variable is the rate of change of the flexion angle The vehicle's speed is assumed to be constant, with initial parameters The real dynamic motion behavior of the walking platform is as follows Figure 1 As shown. Because, setting l1=l2, the matrix of the vehicle motion model is:

[0068]

[0069] 2. Yaw correction

[0070] For the two-dimensional coordinate points of the predetermined path, the work vehicle needs to adjust the steering and update the path points according to its own information and target information, so the movement process of the work vehicle in the geodetic coordinate system is established as follows: Fig.16

[0071]

[0072] x=-ecosθ r (14)

[0073] y=-esinθ r (15)

[0074] Where: e——error distance;

[0075] θ r ——the direction of the error vector relative to the target;

[0076] θ t ——The angle between the distance vector e and the linear velocity vector.

[0077] The time derivative of (13) can be written as

[0078]

[0079] Combine (14)(15)(16) to get

[0080]

[0081] Substituting (4)(5) into (17), we obtain

[0082]

[0083] Substituting the inverse of the time of (14) (15) into (4) (5) we get

[0084]

[0085] Depend on Figure 2 Analysis shows that θ t =θ r -ψ,

[0086]

[0087] Combined with kinematic analysis, we can get

[0088]

[0089] Combined with the kinematic model matrix (12), the motion equation of the work vehicle in polar coordinates can be summarized as

[0090]

[0091] In the field of automatic control, Lyapunov stability can be used to describe the stability of a dynamic system. Lyapunov stability theory is a common tool for designing control systems. Here we consider a simple quadratic equation as a candidate Lyapunov function.

[0092] The purpose of the steering control system is to control the vehicle so that it is precisely aligned with the target. Can drive the work vehicle from any initial position (e(0),θ r (0),θ t (0)) to a small neighborhood of the target (0,0,0).

[0093] Consider the positive form

[0094]

[0095] The time derivative of V is

[0096]

[0097] Substituting (22) into (24) we obtain

[0098]

[0099] Expand

[0100]

[0101]

[0102] Through stability theory analysis, we can get

[0103]

[0104] Combining formula (20), we can get

[0105]

[0106] When λ2>0 and When is positive, we find from (4-51) that θ r is stable and eventually approaches zero, it can proceed slowly.

[0107] therefore, Leading to (e, θ r ,θ t )→(0, 0, 0). Since the system has no drift. In fact, a trade-off is needed when selecting parameters. Setting λ4=0 stabilizes (e, θ r ,θ t ), while making φ uncontrollable. In this case, φ can take physically unrealizable values, for example, making the steering chassis fold over itself. In contrast, choosing λ4 too large will result in a very slow origin. It should also be mentioned that the proposed center articulated work vehicle model has a singularity at e = 0, because according to formula (4-22), there is no definition at and The condition e=0 cannot occur within a finite time.

[0108] Finally, we note that there is a special case where the controller cannot stabilize the robot configuration. t This special case occurs when both are initially zero. From equations (26) and (27), we can observe that in this case, ω = 0 and v = λ1, θ r The control system recognizes this special situation and takes appropriate measures, such as setting the initial angle to non-zero, setting the output target attitude value to the drive motor and steering motor, calculating the PWM output of each motor, calling the communication subroutine, communicating with the host computer, and displaying and adjusting the working parameters (operating vehicle travel speed, environmental information, path information) in real time.

[0109] The variable is the rate of change of the flexion angle The vehicle's speed is assumed to be constant, with initial parameters The matrix of the vehicle motion model is:

[0110]

[0111] 3. Strapdown Inertial Navigation

[0112] Inertial navigation systems are divided into platform-based inertial navigation and strapdown inertial navigation. Early inertial navigation systems were all platform-based. Platform-based inertial navigation systems have a physical platform with gyroscopes and accelerometers placed on a platform stabilized by a gyroscope. The platform tracks the navigation coordinate system to achieve velocity and position resolution, and attitude data is directly taken from the platform's gimbal.

[0113] Advantages: Directly simulate the navigation coordinate system, the calculation is relatively simple; can isolate the angular motion of the carrier, the system has high accuracy; Disadvantages: complex structure, large size, and high production cost.

[0114] There is another type of strapdown inertial navigation. The original meaning of strapdown in English is "binding". Therefore, strapdown inertial navigation is to install inertial measurement elements, including gyroscopes and accelerometers, directly on the main body that needs navigation information such as attitude, speed, and heading, and use the computer's measurement signals to convert into navigation parameters.

[0115] The advantages are that there is no platform, the structure is simple, the size is small, and the maintenance is easy. The disadvantages are: the inertial components are directly installed on the carrier, the environment is harsh, and the requirements for the components are high; the coordinate transformation requires a large amount of calculation. Overall, the strapdown inertial navigation has obvious advantages over the platform-type inertial navigation.

[0116] 4. Motor control

[0117] 4.1 PID control

[0118] The PID (proportional-integral-derivative) controller originated from the design of speed governors in the 1890s. PID controllers gradually developed in the automatic operating systems of ships. The controller developed by Elmer Sperry in 1911 was one of the earliest PID controllers, and the first engineer to publish a theoretical analysis of PID controllers was Russian-American engineer Nicolas Minorsky (1922). Minorsky derived mathematical formulas based on the controller for stability rather than general control, which greatly simplified the problem. Proportional control can maintain stability under small disturbances, but it cannot eliminate steady-state errors, so an integral term is added, followed by a differential term.

[0119] The control loop consists of three parts: the measurements taken by the system's sensors, the controller making the decision, and then reacting through the execution hardware. The controller takes the measurement from the sensor and then subtracts the measurement from the demand result to get the difference. This value is used to calculate the correction value of the system as input so that the system can eliminate the error in its output. This correction has three algorithms to eliminate the current error value, average the past error values, and predict the future error value through the change of the difference value.

[0120] PID controllers can be used to control any variable that can be measured and controlled. For example, it can be used to control temperature, pressure, flow, chemical composition, speed, etc. The cruise control function on a car is an example. In industrial control applications, PID controllers are commonly used feedback loop components. The controller compares the collected data with the reference value and then uses the difference to calculate the new input value. The purpose of the calculation is to allow the system data to reach or maintain the reference value. The PID controller can adjust the input value based on historical data and the occurrence rate of the difference to improve the accuracy and stability of the system. As shown in Figure 16, the PID controller can be regarded as a filter for the frequency domain system. This property is very important when calculating whether the controller will eventually reach a stable result. If the value is not selected properly, the input value of the control system will oscillate repeatedly, causing the system to never reach the preset value. If the control output is defined as u(t), the PID time domain expression is as follows

[0121] Where: K p ——Proportional gain, debugging parameters;

[0122] K i ——Integral gain, debugging parameters;

[0123] K d ——Differential gain, debugging parameters;

[0124] e——error, the difference between the set value and the measured value;

[0125] t——current time;

[0126] τ——integral variable, value is 0 to current time;

[0127] T i ——integral time constant;

[0128] T d ——Differential time constant.

[0129] The PID controller obtains the control signal u(t) by weighting the error signal e(t), drives the controlled object, and makes the error e(t) change in the decreasing direction, thereby achieving the control requirement. i →∞,T d =0, it is a proportional (P) controller; if T d =0, it is a proportional integral (PI) controller; when T i →∞, it is a proportional derivative (PD) controller; if T i ≠∞, T d ≠0, it is a proportional integral derivative (PID) controller. Determine K p , T i , T d After the three parameter values ​​are determined, the performance of the PID controller is determined.

[0130] analyze Figure 4-5 , perform Laplace transform on (4-1) to obtain the transfer function of the PID controller:

[0131]

[0132] 4.2 Drive Motor Control

[0133] 1) Driving motor mathematical model

[0134] The driving motor of the work vehicle is a separately excited motor

[76] According to the structure and the law of electromagnetic induction, the induced electromotive force and electromagnetic torque of the driving motor are derived, and the voltage balance method of the motor is established by Kirchhoff's second law (KVL).

[0135] E=K e Φn m =C e n m (4-3)

[0136] Where: E——Induced electromotive force of driving motor, V;

[0137] K e ——electromotive force constant;

[0138] Φ——Magnetic flux per pole of the motor, Wb;

[0139] n m ——Motor speed, r / min;

[0140] C e ——Electromotive force speed ratio under rated magnetic flux (V min / r), and C e =K e Φ.

[0141] T e =K T ΦI m =C m I m (4-4)

[0142] Where: T e ——Electromagnetic torque of driving motor, N·m;

[0143] K T ——Torque constant determined by the motor structure;

[0144] I m ——armature current, A;

[0145] C m ——Torque-current ratio at rated flux N·m / A, C m =30π -1 C e .

[0146] When the drive motor is running, the armature equivalent circuit is as follows Fig.19 , the differential equation can be listed as follows

[0147]

[0148]

[0149] Where: T m ——Motor output torque, N·m;

[0150] T L ——Load torque, N·m;

[0151] J——Moment of inertia, N·m 2 .

[0152] From the theoretical analysis of DC motor drive system, is the armature circuit battery time constant, is the electromechanical time constant of the electric traction system. Under zero initial conditions, the time constant is substituted into (4-5) and (4-6), and both sides of the equation are transformed by Laplace equation to obtain the transfer function of the voltage and current linear response system

[0153]

[0154] The current and electromotive force transfer function is

[0155]

[0156] Where: I dL ——Load current.

[0157] The dynamic structure of the DC motor is obtained through formulas (4-6), (4-7), and (4-8), such as Fig. 20 The dynamic structure diagram of the DC motor is shown.

[0158] The acquisition of the posture of the plant protection operation is very important for automatic walking. It requires the cooperation of the strapdown inertial navigation system and the satellite navigation and positioning system to ensure the accuracy and reliability of the data. The extended Kalman filter algorithm is used to filter the data output by the gyroscope and accelerometer. If the interference value is too large, the GPS coordinate information is added to settle the posture information of the operation vehicle. The specific process of posture acquisition is as follows: Fig.13 shown.

[0159] The control modes of the autonomous plant protection work vehicle are manual and automatic, and a remote control can be used for human-computer interaction. In automatic mode, the KML data of the predetermined path can be input. The plant protection work vehicle controller adjusts the steering by reading the IMU attitude information and GPS satellite positioning information, controls the drive motor to move autonomously along the predetermined path, and uses heading tracking to achieve path tracking. The upper computer control software defines the driving path information (KML), communicates with the work vehicle controller by radio or directly stores it in the work vehicle controller. The GPS module installed on the work vehicle receives satellite positioning signals in real time, and the main controller solves the current positioning information with the defined path information to obtain the target heading, control the steering angle and speed, and the path tracking process is as follows: Fig.14 shown.

[0160] During the operation, the vehicle transmits real-time position and speed information through the wireless communication module. The route or speed can be viewed and modified on a computer or mobile phone. The communication method uses the MAVLink protocol, and the open source ground station software developed under this protocol can be used directly. The drive motor of the vehicle needs the controller to output a PWM signal to control the drive motor for speed regulation, and the same is true for the steering motor. The controller uses a pulse trigger switch to control the diaphragm pump of the spray system.

[0161] The upper computer control software (ground station) uses the open source project software QGroundControl, and the communication between the work vehicle and the ground station requires the use of a radio module. The SiK radio module is a small, lightweight and inexpensive open source radio platform that can typically provide a connection range of more than 300 meters (using a patch antenna, the range can be extended to several kilometers). The module uses open source firmware and is specifically designed to work with MAVLink data packets. The communication frequency can be 915Mhz or 433Mhz, the receiver sensitivity is -121dBm, the transmit power is up to 20dBm (100mW), and the serial link air data rate is up to 250kbps.

[0162] The model of the controller is ATMEGA2560-16AU; because it is feedback control, the microcontroller needs to continuously calculate data, and at the same time it needs to continuously receive attitude sensor and positioning information and perform operations on the data, which requires the microcontroller to have a faster computing speed and stronger stability.

[0163] Therefore, this embodiment provides a plant protection operation vehicle with adjustable wheelbase and height. The wheelbase and frame height can be adaptively adjusted according to the row spacing and plant height of the operation. It can be used for full-period spraying of plant protection, has strong versatility, and adopts remote control, which improves the intelligence level of plant protection operations, has a wide range of applications, is easy to operate, and saves manpower.

[0164] Embodiment 2: This embodiment is basically the same as Embodiment 1, except that: this embodiment further defines the folding structure between the main spray bar 10 and the side spray bar 11.

[0165] A folding piece is arranged between the two sides of the main spray rod and the side spray rod, and the folding piece includes an upper cross plate 18, a lower cross bar 19, a central axis 20, a holder 21 and a baffle 23; the upper cross plate 18 and the lower cross bar 19 are respectively arranged at the upper and lower ends of the main spray rod in the horizontal direction. The upper cross plate 18 is a flat plate structure, the lower cross bar 19 is a round rod structure, and the central axis 20 vertically penetrates the upper cross plate and the lower cross bar and can rotate; the holder 21 is trapezoidal and fixed on the central axis, and the bottom of the holder 21 is seated on the lower cross bar 19, the baffle 23 is located on the upper part of the central axis 20, and the spring 22 is sleeved on the central axis and located between the baffle and the holder.

[0166] The present embodiment provides a manually foldable side spray rod structure, so that the side spray rod can be folded on the main spray rod, which is easy to use and can maintain a stable posture in both the folded state and the unfolded state. The structure is stable and the operation is convenient.

[0167] Embodiment 3: This embodiment is basically the same as Embodiment 1, except that this embodiment further describes the height adjustment mechanism.

[0168] The wheel frame is provided with a slot, and the slot is marked with corresponding scales. In this embodiment, the U-shaped bolt is fixed in the slot. The setting of the slot prevents the U-shaped bolt from sliding downward, thereby improving the stability of the clamp. The slots on the four wheel frames are correspondingly arranged and have corresponding scales as references, thereby ensuring the stability of the frame and setting a reference for the height adjustment of the frame.

[0169] Embodiment 4: This embodiment is basically the same as Embodiment 1, except that: this embodiment further describes the structure of the wheelbase adjustment mechanism.

[0170] like Fig.11 As shown, a rack 24 is provided on the upper side of the adjusting rod, a through hole is opened on the adjusting sleeve, a gear 25 is nested in the through hole and meshed with the rack 24, and a structure that can automatically adjust the wheelbase is provided in this embodiment, a motor is provided on the gear, and the motor is connected to the gear transmission, and the gear is driven by controlling the rotation of the motor, and the gear drives the rack, so that the controller controls the direction of the motor to adjust the size of the wheelbase.

Claims

1. An intelligent driving electric plant protection vehicle with adjustable height and wheelbase, characterized in that: It includes a front frame, a rear frame, a folding steering mechanism, a wheelbase adjustment mechanism, a height adjustment mechanism and a spray rod mechanism; the front frame and the rear frame are connected by the folding steering mechanism to form a frame body, a power supply and a remote control receiver are installed on the front frame, a medicine box, a diaphragm pump and a gantry are installed on the rear frame, and the wheelbase adjustment mechanism is arranged between the moving wheel and the frame; the height adjustment mechanism includes a connecting seat, a U-shaped bolt and a wheel frame, the connecting seat is fixed on the frame, the U-shaped bolt passes through the connecting seat and clamps the wheel frame on the connecting seat, and a moving wheel is installed at the bottom of the wheel frame, and each moving wheel is installed with a driving motor; the folding steering mechanism It includes a steering motor, a front bogie, a rear bogie, a gear set and a drive shaft. The front bogie and the rear bogie are fixed at the joints of the front frame and the rear frame respectively; the steering motor is installed on the rear bogie via a bracket, the front bogie is fixed on the drive shaft, and the rear bogie is rotatably arranged at both ends of the drive shaft; the steering motor is connected to the drive shaft via a gear set, so that the front bogie can rotate relative to the rear bogie under the drive of the steering motor; the spray rod mechanism includes a lifting frame, side wheels, an electric push rod, a main spray rod and a side spray rod; side wheels are arranged on both sides of the lifting frame, and the side wheels are nested on the tracks on both sides of the gantry. The push rod is arranged between the lifting frame and the gantry, and is used to drive the lifting frame to rise and fall along the gantry; the main spray rod is fixed on the lifting frame, and the side spray rod is folded and arranged on the main spray rod, and the gear set includes a driving gear, a driven gear, a set gear and a driving gear; a driving gear is set on the rotating shaft of the steering motor, the driving gear is meshed with the driven gear, the set gear is coaxially set on the lower part of the driven gear, and the driving gear is meshed with the set gear; the lower part of the driving gear is fixedly set on the upper part of the driving shaft, and folding parts are arranged between the two sides of the main spray rod and the side spray rod, and the folding parts include an upper cross plate, a lower cross bar, a middle shaft, a card seat and a baffle; the upper cross plate The upper and lower cross bars are respectively arranged at the upper and lower ends of the main spray rod in the horizontal direction, and the central axis penetrates the upper cross plate and the lower cross bar in the vertical direction and can rotate; the holder is in a trapezoidal structure, the holder is fixed on the central axis, and its bottom is seated on the tubular lower cross bar, the baffle is located on the upper part of the central axis, the spring is sleeved on the central axis and is located between the baffle and the holder, and the wheelbase adjustment mechanism includes an adjustment sleeve, an adjustment rod and a limit bolt; the adjustment sleeve is fixed on the front frame, the adjustment rod is sleeved in the adjustment sleeve, and the adjustment sleeve and the adjustment rod are respectively provided with a fixing hole and a plurality of positioning holes; the limit bolt is adjusted in the fixing hole and the positioning hole to maintain the position of the adjustment rod and the adjustment sleeve.

2. The height and wheelbase adjustable intelligent driving electric plant protection vehicle according to claim 1, characterized in that: The wheel frame is provided with a slot, on which a corresponding scale is marked, and the U-shaped bolt is matched with a sleeve in the slot.

3. The height and wheelbase adjustable intelligent driving electric plant protection vehicle according to claim 1 is characterized by: It also includes a control system, which includes a posture sensor, a host computer, a controller, a diaphragm pump, a drive motor and a steering motor; the posture sensor is used to receive the vehicle condition information of the plant protection vehicle and upload the vehicle condition information to the controller, the host computer sends instructions to the controller via a wireless module, and the signal output end of the controller controls the operation of the diaphragm pump, the drive motor and the steering motor to adjust the spray power, vehicle speed and steering of the plant protection vehicle.

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