A control system and control method for work vehicle off-board support leveling

Abstract

This invention discloses a control system and method for leveling and supporting a work vehicle under its vehicle, which obtains the ground tilt θ. x0 θ y0 and setting the disembarkation height data h s The extension length L of the outriggers after leveling is predicted. sx Extend four vertical outriggers, based on the distance sensor data h and the chassis tilt angle data θ. x θ y And the outrigger span, calculate the extension length L of each vertical outrigger in real time. x The remaining three outriggers continue to extend, and the control signal U they are loaded with... x Based on the extension length L x and setting the extension length L sx The difference between them is adjusted in a closed loop; when the chassis tilt angle is close to 0°, all outrigger extension actions are stopped, and the vehicle support leveling is completed. This invention corrects the distance sensor measurement data according to the ground tilt and chassis tilt information, thereby improving the accuracy of the distance sensor data.

Description

TECHNICAL FIELD

[0001] The present application relates to a control system and control method for supporting and leveling of a lower vehicle, and belongs to the technical field of work vehicles. BACKGROUND

[0002] Many engineering machinery and special work vehicles, including overhead working vehicles, high-altitude fire fighting vehicles, truck cranes, concrete pump trucks, etc., can be divided into lower vehicles and upper vehicles according to their structural composition, such as Figure 1 The lower vehicle is mainly composed of a chassis, a vehicle frame and supporting legs installed on both sides thereof, and can be supported and leveled by the supporting legs to make the vehicle leave the ground and be in a horizontal state, and the supporting legs are generally four. The upper vehicle is composed of a rotating platform, a working arm frame, etc. When the vehicle is working using the working arm frame of the upper vehicle, the lower vehicle needs to be supported and leveled first to make the lower vehicle in a horizontal state and the chassis tires leave the ground. This is to provide a horizontal reference platform for the work of the upper vehicle, and to ensure the safety of the vehicle by supporting the entire vehicle weight on the four supporting legs. The operator also has the demand of setting the height of the lower vehicle support during the use of the vehicle, i.e. supporting the vehicle at a set ground clearance, such as adapting to the demand of inclined road surface, the demand of fixed-point work of overhead working vehicles and high-altitude fire fighting vehicles, etc.

[0003] The disadvantages of the prior art are as follows:

[0004] ① Multiple detection devices are needed, which increases the cost of the vehicle. At the same time, any failure of the sensor will make the supporting and leveling operation of the lower vehicle unable to proceed normally, which reduces the use reliability of the vehicle. ② There is a relative angle between the distance measuring sensor and the measured object, i.e. when the distance measuring sensor is in an inclined state, there is an error between the measured distance and the actual distance. According to the inclination degree of the distance measuring sensor, the measured distance can be corrected to improve the measurement accuracy. There is no related correction processing in the prior art. ③ The prior art has no lower vehicle set height support function, and cannot meet the application scenario of the lower vehicle working at a preset ground clearance. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art, and provides a control system and control method for supporting and leveling of a lower vehicle of a work vehicle, which enables the work vehicle to realize one-key supporting and leveling of the lower vehicle at a set height with low cost and high reliability, and improves the application scenario adaptability of the vehicle. At the same time, according to the inclination degree of the ground and the inclination information of the chassis, the measured data of the chassis distance measuring sensor is corrected to improve the accuracy of the lower vehicle ground clearance data.

[0006] To achieve the above-mentioned purpose, the present application is implemented by using the following technical solutions:

[0007] In a first aspect, the present application provides a control system for supporting and leveling of a lower vehicle of a work vehicle, comprising:

[0008] a plurality of leg force detection units installed in each of the plurality of legs for detecting a contact condition of each of the plurality of legs with the ground to identify whether each of the plurality of legs is in a virtual leg state;

[0009] a chassis tilt sensor installed at a vehicle gravity center of a lower surface of the chassis for detecting a tilt degree of the vehicle body in left-right and front-rear directions;

[0010] a chassis distance sensor installed at the same position as the chassis tilt sensor for detecting a distance between the chassis and the ground;

[0011] a controller including an input signal processing unit, a set height support leveling control unit and a signal output unit, wherein:

[0012] the input signal processing unit is configured to collect information of the leg force detection units, the chassis tilt sensor and the chassis distance sensor and send the information to the set height support leveling control unit;

[0013] the set height support leveling control unit is configured to execute a control algorithm of set height support leveling operation according to the information sent by the input signal processing unit and send a control signal to the signal output unit;

[0014] the signal output unit is configured to drive each of the plurality of legs to perform telescopic movement at different speeds according to the received control signal.

[0015] Further, the chassis distance sensor is any one of a microwave distance sensor, an ultrasonic distance sensor, an infrared distance sensor and a laser distance sensor.

[0016] Further, the controller further includes an operation element configured to send a get-off support leveling command signal to the input signal processing unit.

[0017] Further, the controller further includes a human-computer interaction unit configured to receive information sent by the input signal processing unit, display the sent information and modify a set ground clearance for getting off.

[0018] Further, the signal output unit drives the plurality of legs to move through a leg hydraulic proportional valve, and the greater the control signal loaded, the faster the telescopic speed of the plurality of legs, and vice versa.

[0019] In a second aspect, the present application provides a control method for supporting and leveling of a work vehicle, which is suitable for the control system for supporting and leveling of a work vehicle as described in any one of the preceding aspects, and the method comprises:

[0020] obtaining chassis tilt sensor data including ground tilt angles in X and Y directions, respectively represented by θ x0 and θ y0 ;

[0021] According to θ x0 and θ y0 , the set extension length of each leg after leveling is calculated and recorded as L sx , where x = 1, 2, 3, 4.

[0022] According to the set extension length of each leg, four vertical legs are extended, and the control signal U x of the four vertical legs is loaded. max , where x = 1, 2, 3, 4.

[0023] After all four legs are under stress, the ranging sensor data h, chassis inclination data θ x , and θ y are obtained.

[0024] According to the ranging sensor data h, chassis inclination data θ x , and θ y , the extension length of each vertical leg is calculated and recorded as L x , where x = 1, 2, 3, 4.

[0025] When the extension length L i of the i-th leg reaches L si , the extension action of this leg is stopped, and the control signal U i loaded on the corresponding leg is set to 0.

[0026] The remaining three legs continue to extend, and the control signal U x is adjusted according to the difference between the extension length L x and the set extension length L sx , achieving motion deceleration.

[0027] When |θ x | < ε and |θ xy | < ε, the extension action of all legs is stopped, and U x = 0; where ε is a horizontal state judgment value, used to judge that the chassis inclination is very small and the vehicle has reached a horizontal state, at which point the vehicle set height support leveling is completed.

[0028] Further, the smaller the difference between the extension length L x and the set extension length L sx , the smaller the control signal U x , the closer to the preset minimum control signal U min , and the slower the extension speed.

[0029] Further, dynamic sliding filtering is performed on the collected sensor data throughout the process.

[0030] Further, the extension length Lx The calculation formula is as follows:

[0031] When the ground is horizontal, in a three-dimensional coordinate system, assuming that the vertical distance from the ranging sensor mounting point o to the ground is h o On the normal line oZ of the oXY plane, the angle between the ranging sensor and oZ is denoted as θ z Then, the following is obtained:

[0032]

[0033]

[0034] By combining formula 5-1 and formula 5-2, the following is obtained:

[0035] The extension lengths of the four vertical legs are calculated, and the formula is as follows:

[0036]

[0037] L1=h o +W F ×sinθ y +W L ×sinθ x (Formula 5-4)

[0038] L2=h o +W F ×sinθ y -W R ×sinθ x (Formula 5-5)

[0039] L3=h o -W B ×sinθ y -W R ×sinθ x (Formula 5-6)

[0040] L4=h o -W B ×sinθ y +W F ×sinθ x (Formula 5-7)

[0041] The inclination degrees of the X and Y directions are denoted as θ x and θ y , and the extension lengths of the vertical legs are denoted as L x , where x=1, 2, 3, 4; the vertical distance from the ranging sensor mounting point o to the ground is h o ; the distance measured by the ranging sensor from the ground is denoted as h, and W L is the span of the left leg to the center of gravity o, and WR W is the span of the right side leg to the center of gravity o B W is the span of the rear side leg to the center of gravity o F W is the span of the front side leg to the center of gravity o

[0042] When the ground is inclined, assuming that the ground is inclined by θ x0 and θ y0 ≠ 0, θ x0 ≠ 0, the extension lengths of the four vertical legs on the inclined ground are calculated as follows: y0

[0043]

[0044]

[0045] L1 = h o + W F × sin θ y + W L × sin θ x - W F × sin θ y0 - W L × sin θ x0 (Formula 5-10)

[0046] L2 = h o + W F × sin θ y - W R × sin θ x - W F × sin θ y0 + W R × sin θ x0 (Formula 5-11)

[0047] L3 = h o - W B × sin θ y - W R × sin θ x + W B × sin θ y0 + W R × sin θ x0 (Formula 5-12)

[0048] L4 = h o - W B × sin θ y + W F × sin θ x + W B × sin θ y0 - W F × sin θ​x0 (Formula 5-13)

[0049] wherein, o point is the center of gravity of the vehicle, h o is the vertical distance from the distance sensor mounting point o to the ground, W L is the span of the left side leg to the center of gravity o, W R is the span of the right side leg to the center of gravity o, W F is the span of the front side leg to the center of gravity o.

[0050] Further, the each leg is set to extend length L sx The calculation formula is as follows:

[0051] L s1 = h s -W F × sin θ y0 -W L × sin θ x0 (Formula 5-14)

[0052] L s2 = h s +W F × sin θ y0 +W R × sin θ x0 (Formula 5-15)

[0053] L s3 = h s +W B × sin θ y0 +W R × sin θ x0 (Formula 5-16)

[0054] L s4 = h s +W B × sin θ y0 -W F × sin θ x0 (Formula 5-17)

[0055] wherein, h s is the set ground clearance, W L is the span of the left side leg to the center of gravity o, W R is the span of the right side leg to the center of gravity o, W B is the span of the rear side leg to the center of gravity o, W F is the span of the front side leg to the center of gravity o.

[0056] Compared with the prior art, the present application has the beneficial effects:

[0057] 1. The application provides a control system and method for supporting and leveling of a work vehicle, wherein the extension length of four vertical supporting legs can be obtained according to the ground inclination, chassis inclination information and supporting leg span information through a distance sensor, thereby reducing the cost of the vehicle, reducing the risk caused by component failure and improving the reliability of the vehicle in use.

[0058] 2. The application provides a control system and method for supporting and leveling of a work vehicle, wherein the measurement data of the distance sensor is corrected according to the ground inclination and chassis inclination information, thereby improving the accuracy of the data of the distance sensor.

[0059] 3. The application provides a control system and method for supporting and leveling of a work vehicle, which realizes the supporting and leveling of the work vehicle at a set height and can modify the set ground clearance of the work vehicle through a man-machine interaction unit, thereby improving the application scene adaptability of the vehicle. BRIEF DESCRIPTION OF DRAWINGS

[0060] Figure 1 It is a general structure diagram of a work vehicle provided by the background technology of the application.

[0061] Figure 2 It is a structure diagram of a control system for supporting and leveling of a work vehicle provided by the embodiment of the application.

[0062] Figure 3 It is a supporting diagram of the work vehicle provided by the embodiment of the application.

[0063] Figure 4 It is a diagram for decomposing the chassis inclination information to oXZ plane provided by the embodiment of the application.

[0064] Figure 5 It is a diagram for decomposing the chassis inclination information to oYZ plane provided by the embodiment of the application.

[0065] Figure 6 It is a control method flow chart for supporting and leveling of the work vehicle at a set height provided by the embodiment of the application. DETAILED DESCRIPTION

[0066] The application will be further described below in combination with the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the application, and cannot be used to limit the protection scope of the application.

[0067] Embodiment 1

[0068] This embodiment introduces a control system for supporting and leveling of a work vehicle, which comprises a controller, a man-machine interaction unit, a supporting leg stress detection unit, a chassis inclination sensor, a chassis distance sensor, an operating element and a hydraulic proportional valve for controlling the extension and retraction of the vertical supporting legs.

[0069] The off-car support leveling control system as shown in the figure comprises: Figure 2

[0070] (1) The operating element (21) provides off-car support leveling command signals. When the operating element is pressed, the controller starts to perform off-car support leveling operation.

[0071] (2) The man-machine interaction unit (22) displays the state information of off-car leveling operation, and can also modify the off-car ground clearance.

[0072] (3) The leg force detection unit (23) has four units, which detect the contact of the four legs with the ground to identify whether the legs are in the virtual leg state.

[0073] (4) The chassis inclination sensor (24) is installed at the vehicle gravity center of the chassis bottom surface, which detects the inclination degree of the vehicle body in the left-right and front-rear directions.

[0074] (5) The chassis distance sensor (25) is installed at the same position as the chassis inclination sensor, which detects the distance between the chassis and the ground, which can be a microwave distance sensor, an ultrasonic distance sensor, an infrared distance sensor or a laser distance sensor, etc.

[0075] (6) The controller (26) comprises an input signal processing unit (261), a set height support leveling control unit (262) and a signal output unit (263), wherein:

[0076] The input signal processing unit (261) collects the information of the leg force detection unit (23), the chassis inclination sensor (24) and the chassis distance sensor (25), and performs filtering, conversion and other operations. The signal of the operating element (21) is received to obtain the start instruction of the off-car support leveling operation. The information is interacted with the man-machine interaction unit (22) to receive the set ground clearance data, and the information including the chassis inclination degree and the chassis ground clearance is sent to the man-machine interaction unit (22) for display.

[0077] The set height support leveling control unit (262) executes the control algorithm of the set height support leveling operation.

[0078] The signal output unit (263) loads the control signal obtained by the set height support leveling control unit (262) to the leg hydraulic proportional valve (27) through the valve control module.

[0079] ​(7) The outrigger hydraulic proportional valve (27) outputs a control signal through the loading signal output unit (263), and the proportional valve opening produces different degrees of opening to drive the outrigger to extend and retract at different speeds. The greater the loaded control signal, the faster the outrigger extension and retraction speed, and vice versa. The control signal corresponding to the minimum opening of the outrigger hydraulic proportional valve is recorded as U min , and the control signal corresponding to the maximum opening is recorded as U max .

[0080] In specific use, the embodiment includes:

[0081] ① The ground inclination degree is measured using the chassis inclination sensor.

[0082] ② According to the ground inclination degree, the outrigger span, and the set height value, the set extension length L sx of each vertical outrigger when the vehicle is at the set ground clearance after the vehicle leveling is completed is predicted, x = 1, 2, 3, 4, corresponding to the left front outrigger, the right front outrigger, the right rear outrigger, and the left rear outrigger, respectively.

[0083] ③ The ground clearance value measured by the distance sensor is corrected according to the ground inclination degree and the chassis inclination information to eliminate the error problem caused by the ground inclination and the chassis inclination to the distance sensor.

[0084] ④ After all four outriggers are stressed, the extension length L x of each vertical outrigger is calculated in real time according to the ground inclination degree, the chassis inclination degree, the vehicle ground clearance, and the outrigger span, x = 1, 2, 3, 4, corresponding to the left front outrigger, the right front outrigger, the right rear outrigger, and the left rear outrigger, respectively.

[0085] ⑤ When the vehicle is leveled, the four vertical outriggers are extended synchronously, and the loading control signal of the hydraulic proportional valve is maximum. When the extension length L i of the i-th outrigger reaches L si , the extension action of this outrigger is stopped. The remaining three outriggers continue to extend, and the loading control signal U x is closed-loop adjusted according to the difference between the extension length L x and the set extension length L sx . When the chassis inclination approaches 0°, the extension action of all outriggers is stopped, and at this time the vehicle leveling is completed.

[0086] ⑥ The set ground clearance value of the vehicle should be selected to be just enough to ensure that all tires can be off the ground, so that the vehicle leveling can be quickly completed and the vehicle leveling time is shortened. The set ground clearance of the vehicle can also be modified by the operator according to the application scenario through the human-computer interaction unit.

[0087] Embodiment 2

[0088] The control method for supporting and leveling of the work vehicle provided by the embodiment is applicable to the control system for supporting and leveling of the work vehicle described in Embodiment 1, and each vertical supporting leg extension length is calculated through the ground inclination, the chassis inclination sensor, the chassis distance sensor and the supporting leg span.

[0089] First, taking the horizontal ground as an example, the calculation formula is derived.

[0090] As shown in Figure 3 , it is a supporting schematic diagram of the work vehicle, and o point is the gravity center of the vehicle and the installation position of the chassis inclination sensor and the distance sensor. The chassis inclination sensor can measure the inclination of two directions X and Y as shown in the figure, which are denoted as θ x and θ y . When the left side is high, θ x > 0; when the front side is high, θ y > 0. The extension length of the four vertical supporting legs is denoted as L x , wherein x = 1, 2, 3, 4, respectively corresponding to the left front supporting leg, the right front supporting leg, the right rear supporting leg and the left rear supporting leg. The vertical distance from the distance sensor installation point o to the ground is h o , and the distance measured by the distance sensor from the ground is denoted as h. Since the distance measured by the distance sensor is the distance from the normal of the sensor installation surface to the ground, when the chassis is in an inclined state, h≠ h o . Therefore, the ground clearance information measured by the distance sensor needs to be corrected according to the chassis inclination.

[0091] In a three-dimensional coordinate system, it is assumed that the vertical distance from the distance sensor installation point o to the ground is h o on the normal oZ of the oXY plane, and the angle between the distance h measured by the distance sensor and oZ is denoted as θ z , then,

[0092]

[0093]

[0094] By combining formula 5-1 and formula 5-2, we can get,

[0095]

[0096] The chassis inclination information is decomposed into oXZ plane and oYZ plane, as shown in Figure 4 and Figure 5 , wherein W L is the span of the left supporting leg to the gravity center o, W R is the span of the right supporting leg to the gravity center o, W B is the span of the rear supporting leg to the gravity center o, and W F is the span of the front supporting leg to the gravity center o.

[0097] The length of the four vertical legs can be calculated, and it is known that,

[0098] L1 = h o +W F × sin θ y +W L × sin θ x ; (5-4)

[0099] L2 = h o +W F × sin θ y -W R × sin θ x ; (5-5)

[0100] L3 = h o -W B × sin θ y -W R × sin θ x ; (5-6)

[0101] L4 = h o -W B × sin θ y +W F × sin θ x ; (5-7)

[0102] Similarly, assuming that the ground is inclined by θ x0 and θ y0 , and θ x0 ≠ 0, θ y0 ≠ 0, the relationship between h o and h on the inclined ground can be derived as

[0103]

[0104]

[0105] The length of the four vertical legs on the inclined ground is:

[0106] L1 = h o +W F × sin θ y +W L × sin θ x -W F × sin θ y0 -W L × sin θ x0 ; (5-10)

[0107] L2 = h o +WF x sin θ y -W R x sin θ x -W F x sin θ y0 +W R x sin θ x0 ; (Formula 5-11)

[0108] L3 = h o -W B x sin θ y -W R x sin θ x +W B x sin θ y0 +W R x sin θ x0 ; (Formula 5-12)

[0109] L4 = h o -W B x sin θ y +W F x sin θ x +W B x sin θ y0 -W F x sin θ x0 ; (Formula 5-13)

[0110] According to the set height h s , the set length L sx of the outrigger is predicted after leveling is completed, where x = 1, 2, 3, 4, respectively corresponding to the left front outrigger, the right front outrigger, the right rear outrigger and the left rear outrigger. After leveling is completed, θ x = 0, θ y = 0, and according to Formula 5-11 to Formula 5-13, it can be known that

[0111] L s1 = h s -W F x sin θ y0 -W L x sin θ x0 ; (Formula 5-14)

[0112] L s2 = h s -W F x sin θ y0 +W R x sin θ x0 ; (Formula 5-15)

[0113] L s3 = h s +WB x sin θ y0 + W R x sin θ x0 ; (5-16)

[0114] L s4 = h s + W B x sin θ y0 = W F x sin θ x0 ; (5-17)

[0115] The control method for supporting and leveling of the work vehicle provided by the embodiment specifically comprises the following steps:

[0116] S1: pressing the operating element to start supporting and leveling of the work vehicle.

[0117] S2: recording the chassis inclination sensor data as θ x0 and θ y0 to obtain the degree of ground inclination. The data is not updated in the current supporting and leveling operation.

[0118] S3: reading the off-ground height data set by the man-machine interaction unit as h s . The data is not updated in the current supporting and leveling operation.

[0119] S4: predicting the set extension length of each supporting leg after leveling according to formulas 5-14 to 5-17, and recording the set extension length of each supporting leg as L sx , wherein x = 1, 2, 3, and 4 respectively correspond to the left front supporting leg, the right front supporting leg, the right rear supporting leg, and the left rear supporting leg. The data is not updated in the current supporting and leveling operation.

[0120] S5: extending the four vertical supporting legs and loading the control signal U x = U max of the four vertical supporting leg proportional valves, wherein x = 1, 2, 3, and 4 respectively correspond to the left front supporting leg, the right front supporting leg, the right rear supporting leg, and the left rear supporting leg.

[0121] S6: after the four supporting legs are all stressed, calculating the extension length of each vertical supporting leg in real time according to the ranging sensor data h, the chassis inclination data θ x , θ y , and formulas 5-10 to 5-13, and recording the extension length of each vertical supporting leg as L x , wherein x = 1, 2, 3, and 4 respectively correspond to the left front supporting leg, the right front supporting leg, the right rear supporting leg, and the left rear supporting leg.

[0122] S7: when the extension length L i of the i-th supporting leg reaches L siWhen the difference between the extension length L i = 0.

[0123] S8: The remaining three legs continue to extend, and the load control signal U x According to the difference between the extension length L x and the set extension length L sx , closed-loop regulation is performed to achieve motion deceleration. The smaller the difference between the extension length L x and the set extension length L sx , the smaller the load control signal U x , the closer to the minimum control signal U mi n, and the slower the extension speed.

[0124] S9: When | θ x | < ε and | θ xy | < ε, stop all leg extension actions, and U x = 0. Wherein ε is a horizontal state judgment value, used to judge that the chassis inclination is very small, and the off-vehicle has reached a horizontal state. At this time, the off-vehicle set height support leveling is completed.

[0125] During the entire process, dynamic sliding filtering is performed on the collected sensor data to eliminate sensor value disturbances caused by chassis motion vibration and other factors. The control method flowchart of the off-vehicle set height support leveling is shown in Figure 6 .

[0126] The present application enables the work vehicle to realize one-key off-vehicle set height support leveling at low cost and high reliability, and improves the vehicle application scene adaptability. At the same time, according to the ground inclination degree and the chassis inclination information, the measurement data of the chassis ranging sensor is corrected to improve the accuracy of the off-vehicle ground clearance height data.

[0127] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled persons in the technical field, several improvements and modifications can be made without departing from the technical principles of the present application, and these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. A control method for work vehicle off-vehicle support leveling, characterized by, The method comprises: The chassis inclination sensor data is acquired, including the ground inclination angles in X and Y directions, respectively represented by and respectively. According to and , the set extension length of each outrigger after the leveling is completed is calculated as , wherein ; According to the set extension length of each leg, four vertical legs are extended, and control signals of four vertical leg proportional valves are loaded = , wherein ; After all four legs are under load, ranging sensor data is acquired , chassis tilt angle data ; According to ranging sensor data , chassis inclination data Calculating each vertical leg extension length, denoted as wherein ; When the The length of each leg extension achieve When this happens, the outrigger extension action stops, and the corresponding control signal is applied to the outrigger. ; The remaining three legs continue to extend, and their load control signals According to the extension length And the difference between the set extension length Closed-loop regulation is achieved by the difference between the extension length When and all the outriggers stop extending, ; wherein is a horizontal state judgment value, used to judge that the chassis inclination angle is very small, and the off-car has reached a horizontal state, at this time, the off-car set height support leveling is completed. the length of each vertical leg The formula for calculating the length of each vertical leg is as follows: When the ground is horizontal, in the three-dimensional coordinate system, assume that the installation point of the distance measuring sensor is The vertical distance to the ground is At The plane normal The distance measuring sensor measures the angle between the distance And Is denoted as Then we have: (Formula 5-1); (Formula 5-2); By combining formula 5-1 and formula 5-2, the following can be obtained: The extension lengths of the four vertical legs are calculated according to the following formula: (Formula 5-3); (Formula 5-4); (Formula 5-5); (Formula 5-6); (Formula 5-7); and the degree of tilt in both directions, denoted by and the vertical leg extension length, denoted by where ; the vertical distance from the ground to the rangefinder mounting point ; the distance from the ground measured by the rangefinder is denoted by , , is the span of the left leg to the center of gravity , is the span of the right leg to the center of gravity , is the span of the rear leg to the center of gravity , is the span of the front leg to the center of gravity ; When the ground is inclined, assuming the degree of inclination of the ground is and , and , the extension length of the four vertical legs under the inclined ground is calculated as follows: (Formula 5-8); (Formula 5-9); (Formula 5-10); (Formula 5-11); (Formula 5-12); (Formula 5-13); wherein, point is the center of gravity of the vehicle, is the mounting point of the distance sensor is the vertical distance to the ground, is the span of the left side leg to the center of gravity is the span of the right side leg to the center of gravity is the span of the rear side leg to the center of gravity is the span of the front side leg to the center of gravity is the span of the front side leg to the center of gravity is the span of the front side leg to the center of gravity is the span of the front side leg to the center of gravity is the span of the front side leg to the center of gravity 2. The control method for work vehicle down truck support leveling of claim 1, wherein, The extension length The smaller the difference between the set extension length The smaller the load control signal The closer to the preset minimum control signal The slower the extension speed.

3. The control method for work vehicle down truck support leveling of claim 1, wherein, During the whole process, the collected sensor data is dynamically and slidingly filtered.

4. The control method for work vehicle down truck support leveling of claim 1, wherein, The legs are set to an extension length The formula for calculating the extension length is as follows: (Formula 5-14); (Formula 5-15); (Formula 5-16); (Formula 5-17); wherein, is the ground clearance, is the span of the left side leg to the center of gravity is the span of the right side leg to the center of gravity is the span of the rear side leg to the center of gravity is the span of the front side leg to the center of gravity is the span of the front side leg to the center of gravity is the span of the front side leg to the center of gravity is the span of the front side leg to the center of gravity is the span of the front side leg to the center of gravity

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