阅读说明：本技术 一种基于电液动推杆的电动拖拉机悬挂系统及控制方法 (Electric tractor suspension system based on electro-hydraulic push rod and control method ) 是由 徐立友 张伟 刘孟楠 吴静波 闫祥海 徐锐良 李忠利 于 2020-07-22 设计创作，主要内容包括：本发明的一种基于电液动推杆的电动拖拉机悬挂系统及控制方法,该悬挂系统包括控制面板、悬挂控制器、位移传感器、拉力传感器、轮速传感器、雷达测速传感器、电液动推杆以及三点悬挂装置；所述电液动推杆包括电机、液压泵、液压集成阀组和液压缸,所述三点悬挂装置包括上拉杆、下拉杆、提升臂和提升杆；本发明中,电动拖拉机悬挂系统耕深控制采用力位—滑转率综合调节,提高电动拖拉机的作业质量和作业效率。克服现有生产的电动拖拉机电动悬挂装置在实际工作过程中抗冲击强度差、机构结构磨损严重、故障率高等问题以及拖拉机滑转率变化较大时,影响拖拉机的作业质量和作业效率。(The invention relates to an electric tractor suspension system based on an electro-hydraulic push rod and a control method, wherein the suspension system comprises a control panel, a suspension controller, a displacement sensor, a tension sensor, a wheel speed sensor, a radar speed measurement sensor, the electro-hydraulic push rod and a three-point suspension device; the electro-hydraulic push rod comprises a motor, a hydraulic pump, a hydraulic integrated valve group and a hydraulic cylinder, and the three-point suspension device comprises an upper pull rod, a lower pull rod, a lifting arm and a lifting rod; in the invention, the tilling depth of the suspension system of the electric tractor is comprehensively regulated by force position-slip ratio, thereby improving the operation quality and the operation efficiency of the electric tractor. The electric suspension device of the electric tractor overcomes the problems that the existing electric suspension device of the electric tractor has poor impact resistance strength, serious abrasion of a mechanism structure, high failure rate and the like in the actual working process, and influences the operation quality and the operation efficiency of the tractor when the change of the slip ratio of the tractor is large.)

1. The utility model provides an electric tractor suspension system based on electro-hydraulic push rod which characterized in that: the device comprises a control panel (1), a suspension controller (2), a displacement sensor (3), a tension sensor (4), a wheel speed sensor (5), a radar speed measurement sensor (6), an electro-hydraulic push rod (7) and a three-point suspension device; the electro-hydraulic push rod (7) comprises a motor (8), a hydraulic pump (9), a hydraulic integrated valve group (10) and a hydraulic cylinder (11), and the three-point suspension device comprises an upper pull rod (14), a lower pull rod (15), a lifting arm (12) and a lifting rod (13);

go up pull rod (14) and lower link (15) and be connected from top to bottom, lift arm (12) are connected with lift rod (13), and lift rod (13) are connected and are established on lower link (15), hang controller (2) and link to each other through cable and electric hydraulic push rod (7), control panel (1), displacement sensor (3), force sensor (4), fast sensor of wheel (5), radar speed sensor (6) respectively, the one end and the frame of electro-hydraulic push rod (7) are articulated, and the other end is articulated with lift arm (12), establish in lift arm (12) corner in displacement sensor (3), force sensor (4) connect and establish in lower link (15) department, fast sensor of wheel (5) are connected and are established on the drive wheel, radar speed sensor (6) are located the automobile body.

2. The electric tractor suspension system based on the electro-hydraulic push rod as claimed in claim 1, wherein: the suspension controller (2) is arranged in the cab operation panel.

3. The electric tractor suspension system based on the electro-hydraulic push rod as claimed in claim 1, wherein: the hydraulic pump is characterized in that the motor (8), the hydraulic pump (9) and the hydraulic integrated valve group (10) are sequentially connected, the hydraulic cylinder (11) is connected with the hydraulic integrated valve group (10), and the hydraulic cylinder (11) is arranged in parallel with the hydraulic pump (9).

4. The electric tractor suspension system based on the electro-hydraulic push rod as claimed in claim 1, wherein: the hydraulic integrated valve group (10) of the electro-hydraulic push rod (7) is composed of an electro-hydraulic reversing valve (16), a one-way valve (17), a hydraulic control one-way valve (18) and an overflow valve (19).

5. An electric tractor suspension system based on electro-hydraulic push rods as claimed in claim 4, wherein: the ascending or descending of the agricultural implement is adjusted by changing the moving direction of a valve core of an electro-hydraulic reversing valve (16) of the electro-hydraulic push rod (7); the check valve (17) is used as a back pressure valve and has a buffering function to prevent the hydraulic oil from flowing back.

6. The electric tractor suspension system based on the electro-hydraulic push rod as claimed in claim 1, wherein: when the piston rod of the electro-hydraulic push rod (7) moves, the lifting arm (12) is driven to rotate around the lifting shaft, and the lifting of the agricultural implement is driven.

7. The method for controlling the suspension system of the electric tractor based on the electro-hydraulic push rod as claimed in claim 1, wherein the method comprises the following steps: the method comprises the following steps:

s1: a hydraulic control one-way valve (18) is connected in series on an oil inlet and an oil return path of the hydraulic cylinder (11), when the motor (8) stops rotating, the hydraulic control one-way valve (18) is immediately closed, the hydraulic system is in a pressure maintaining state, and the farm tool can stop at any position of the stroke;

s2: when the load of the suspension system exceeds the rated load, the motor (8) still runs, and when the pressure of the suspension system is higher than the set pressure of the overflow valve (19), hydraulic oil directly flows back to the oil tank from the overflow valve (19), so that the motor overload can be effectively avoided;

s3: the method comprises the steps that the displacement parameters of a lifting arm (12) detected by a displacement sensor (3) are converted into the farming depth of the farm implements, a tension sensor (4) is used for detecting the soil resistance borne by the farm implements, and the slip rate of the electric tractor can be calculated through the rotating speed detected by a wheel speed sensor (5) and the vehicle speed detected by a radar speed measuring sensor (6);

s4: the proportion of one-position adjustment and force adjustment participating in tilling depth control is set in the suspension system, and the displacement parameters of the lifting arm (12) detected by the displacement sensor (3) are converted into the tilling depth H of the farm implement₁And is integrated with the soil resistance F detected by the tension sensor (4) by using an integration coefficient (H = aH)₁+ (1-a) F/β), outputting a tilling depth comprehensive control value H to realize force position comprehensive tilling depth adjustment, wherein a is the proportion of position adjustment participating in tilling depth control, 1-a is the proportion of force adjustment participating in tilling depth control, and β is soil specific resistance;

s5: the suspension system realizes force position-slip ratio comprehensive tilling depth adjustment, when the slip ratio is not in an optimal slip ratio interval, tilling depth control adopts slip ratio adjustment, and a suspension controller (2) sends a signal to enable the slip ratio to approach the optimal slip ratio interval by changing the tilling depth value; when the slip ratio is in the optimal slip ratio range, the tilling depth control adopts force position comprehensive regulation, and the suspension controller (2) sends out a signal to enable the actual tilling depth value to tend to the set tilling depth value.

Technical Field

The invention belongs to the technical field of tractors, and relates to an electric tractor suspension system based on an electro-hydraulic push rod and a control method.

Background

At present, a power battery pack of an electric tractor provides electric energy for a driving motor, and the driving motor drives wheels through a mechanical transmission device to provide power for the running of the electric tractor. An electric tractor generally adopts an electric suspension device, the electric suspension device is composed of a motor, a speed reducer, a lead screw nut or a worm and gear and other mechanical structures, and the lifting of a suspension mechanism is controlled through the forward and reverse rotation of the motor. When the tractor drives the farm tool to operate, the soil environment is complex, and the load fluctuation is large. The electric suspension device is not provided with a buffer device, the excess load of the electric suspension device is completely born by a mechanical structure during working, the lead screw nut or the worm gear is worn greatly to cause inaccurate positioning, and a motor is easy to burn; in the process of lifting the farm tool, the farm tool has large self weight, and the connecting piece is easy to break. The electric suspension device has poor impact strength, low transmission efficiency, poorly-determined limit position and high failure rate.

When the slip ratio of the tractor is controlled to be 0.10-0.15, the tractor has high-efficiency working efficiency. The tractor tilling depth adjustment mode is forcefully adjusted, position adjustment, force and position comprehensive adjustment and the like, in the actual farming process, particularly, the soil resistance changes greatly when soft and slippery road surfaces and wet and slippery road surfaces, the driving wheels easily slip, and when the tractor slip rate changes greatly, tire abrasion can be aggravated, the fuel consumption rate is increased, the operation quality and the operation efficiency of the tractor are influenced, and at the moment, the traditional force and position tilling depth adjustment mode cannot effectively adjust the tilling depth.

In addition, the electric suspension device of the electric tractor produced in the prior art has the problems of poor impact resistance, serious abrasion of a mechanism structure, high failure rate and the like in the actual working process, and influences the operation quality and the operation efficiency of the tractor when the change of the slip ratio of the tractor is large.

Disclosure of Invention

In view of the above, in order to solve the above-mentioned deficiencies of the prior art, the present invention aims to provide an electric tractor suspension system based on an electro-hydraulic push rod and a control method thereof, wherein the electric tractor suspension system adopts force position-slip ratio comprehensive regulation for tilling depth control, thereby improving the operation quality and the operation efficiency of the electric tractor. The electric suspension device of the electric tractor overcomes the problems that the existing electric suspension device of the electric tractor has poor impact resistance strength, serious abrasion of a mechanism structure, high failure rate and the like in the actual working process, and influences the operation quality and the operation efficiency of the tractor when the change of the slip ratio of the tractor is large.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

an electric tractor suspension system based on an electro-hydraulic push rod comprises a control panel, a suspension controller, a displacement sensor, a tension sensor, a wheel speed sensor, a radar speed measurement sensor, the electro-hydraulic push rod and a three-point suspension device; the electro-hydraulic push rod comprises a motor, a hydraulic pump, a hydraulic integrated valve group and a hydraulic cylinder, and the three-point suspension device comprises an upper pull rod, a lower pull rod, a lifting arm and a lifting rod;

go up pull rod and pull rod from top to bottom and be connected, the lifting arm is connected with the lifting rod, and the lifting rod connection is established on the pull rod down, suspension controller links to each other with electric hydraulic push rod, control panel, displacement sensor, force sensor, the fast sensor of wheel, radar tachometer sensor through the cable respectively, electric hydraulic push rod's one end is articulated with the frame, and the other end is articulated with the lifting arm, displacement sensor establishes in lifting arm corner department, force sensor connects and establishes in pull rod department down, the fast sensor of wheel is connected and is established on the drive wheel, radar tachometer sensor is located the automobile body.

Further, the suspension controller is provided in the cab operation panel.

Further, motor, hydraulic pump, hydraulic pressure integrated valve group connect gradually, the pneumatic cylinder is connected with hydraulic pressure integrated valve group, pneumatic cylinder and hydraulic pump parallel arrangement.

Furthermore, the hydraulic integrated valve group of the electro-hydraulic push rod consists of an electro-hydraulic reversing valve, a one-way valve, a hydraulic control one-way valve and an overflow valve.

Furthermore, the ascending or descending of the agricultural implement is adjusted by changing the moving direction of a valve core of an electro-hydraulic reversing valve of the electro-hydraulic push rod; the check valve is used as a back pressure valve and has a buffering function to prevent the hydraulic oil from flowing back.

Furthermore, when the piston rod of the electro-hydraulic push rod moves, the lifting arm is driven to rotate around the lifting shaft, and the lifting of the agricultural implement is driven.

Further, the control method of the electric tractor suspension system based on the electro-hydraulic push rod comprises the following steps:

s1: hydraulic control one-way valves are connected in series on the oil inlet and return paths of the hydraulic cylinder, when the motor stops rotating, the hydraulic control one-way valves are immediately closed, the hydraulic system is in a pressure maintaining state, and the farm tool can stop at any position of the stroke;

s2: when the load of the suspension system exceeds the rated load, the motor still runs, and when the pressure of the suspension system is higher than the set pressure of the overflow valve, hydraulic oil directly flows back to the oil tank through the overflow valve, so that the motor can be effectively prevented from being overloaded;

s3: the method comprises the following steps of converting lifting arm displacement parameters detected by a displacement sensor into farming depth of agricultural implements, detecting soil resistance borne by the agricultural implements by a tension sensor, and calculating the slip ratio of the electric tractor according to the rotating speed detected by a wheel speed sensor and the vehicle speed detected by a radar speed measuring sensor;

s4: the proportion of one-position regulation and force regulation participating in tilling depth control is set in the suspension system, and the lifting arm displacement parameters detected by the displacement sensor are converted into farming depth H of farm implement₁And the soil resistance F detected by the tension sensor is processed by utilizing the comprehensive coefficientSynthesis (H = aH)₁+ (1-a) F/β), outputting a tilling depth comprehensive control value H to realize force position comprehensive tilling depth adjustment, wherein a is the proportion of position adjustment participating in tilling depth control, 1-a is the proportion of force adjustment participating in tilling depth control, and β is soil specific resistance;

s5: the suspension system realizes force position-slip ratio comprehensive tilling depth adjustment, when the slip ratio is not in an optimal slip ratio interval, tilling depth control adopts slip ratio adjustment, and a suspension controller sends a signal to enable the slip ratio to approach the optimal slip ratio interval by changing a tilling depth value; when the slip ratio is in the optimal slip ratio range, the tilling depth control adopts force position comprehensive regulation, and the suspension controller (2) sends out a signal to enable the actual tilling depth value to tend to the set tilling depth value.

The invention has the beneficial effects that:

according to the electric tractor suspension system based on the electro-hydraulic push rod and the control method, the valve core of the electro-hydraulic reversing valve moves to drive the suspension mechanism to lift, the overflow valve overflows when the system pressure is too high to realize motor overload protection, and when a hydraulic control one-way valve is added in a hydraulic loop to stop a motor, an agricultural implement can stop at any position of a stroke; the slip rate is brought into a tilling depth adjusting mode, the slip rate of the tractor is controlled within an optimal slip rate interval by changing a tilling depth value, force position-slip rate comprehensive adjustment is carried out, and the operation quality and the operation efficiency of the electric tractor are improved. The electric suspension device of the electric tractor overcomes the problems that the existing electric suspension device of the electric tractor has poor impact resistance strength, serious abrasion of a mechanism structure, high failure rate and the like in the actual working process, and influences the operation quality and the operation efficiency of the tractor when the change of the slip ratio of the tractor is large. The concrete points are as follows:

the electric tractor suspension system can adjust the rising, falling or neutral of the agricultural implement by changing the moving direction of the electro-hydraulic push rod electro-hydraulic reversing valve core; the electro-hydraulic push rod is connected with a hydraulic control one-way valve in series on the oil inlet and return paths of the hydraulic cylinder, when the motor stops rotating, the hydraulic control one-way valve is immediately closed, the hydraulic system is in a pressure maintaining state, and the agricultural implement can stop at any position of the stroke; when the load of the farm implement exceeds the rated load, the electric hydraulic push rod motor of the electric tractor suspension system still operates, and when the pressure of the system is overhigh, hydraulic oil directly flows back to an oil tank through an overflow valve, so that the motor overload can be effectively avoided;

the electric tractor suspension system brings the slip ratio into a tilling depth control range, when the slip ratio is detected not to be within an optimal slip ratio interval, tilling depth control adopts slip ratio adjustment, and at the moment, a suspension controller sends a signal to enable the slip ratio to approach the optimal slip ratio interval by changing a tilling depth value; when the slip ratio is detected to be in the optimal slip ratio range, the tilling depth is controlled by adopting force position comprehensive regulation, and the suspension controller sends a signal to enable the actual tilling depth value to tend to the set tilling depth value. The tilling depth control precision and the control adaptability of a suspension system of the electric tractor are improved, and the operating efficiency of the electric tractor is improved;

the suspension system based on the electro-hydraulic push rod has the advantages of stepless speed regulation, automatic overload protection, self locking, compact structure, safety, reliability and the like; the tilling depth is controlled by comprehensively regulating the force position-slip ratio, so that the tilling depth uniformity can be ensured, the slip of the tractor is reduced, and the operating efficiency of the electric tractor is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a schematic structural view of an electro-hydraulic ram of the present invention;

FIG. 3 is a schematic diagram of the operation of the electro-hydraulic ram of the present invention;

FIG. 4 is a flowchart of the tilling depth adjustment process of the present invention;

the labels in the figure are: 1. control panel, 2, suspension controller, 3, displacement sensor, 4, tension sensor, 5, the fast sensor of wheel, 6, radar speed sensor, 7, electric hydraulic push rod, 8, motor, 9, the hydraulic pump, 10, hydraulic pressure integrated valves, 11, the pneumatic cylinder, 12, the lift arm, 13, the lift bar, 14, go up the pull rod, 15, the pull rod, 16, electric hydraulic directional control valve, 17, the check valve, 18, the hydraulically controlled check valve, 19, the overflow valve.

Detailed Description

The following specific examples are given to further clarify, complete and detailed the technical solution of the present invention. The present embodiment is a preferred embodiment based on the technical solution of the present invention, but the scope of the present invention is not limited to the following embodiments.

An electric tractor suspension system based on an electro-hydraulic push rod comprises a control panel 1, a suspension controller 2, a displacement sensor 3, a tension sensor 4, a wheel speed sensor 5, a radar speed measurement sensor 6, an electro-hydraulic push rod 7 and a three-point suspension device; the electro-hydraulic push rod 7 comprises a motor 8, a hydraulic pump 9, a hydraulic integrated valve group 10 and a hydraulic cylinder 11, and the three-point suspension device comprises an upper pull rod 14, a lower pull rod 15, a lifting arm 12 and a lifting rod 13;

go up pull rod 14 and lower link 15 and be connected from top to bottom, lift arm 12 is connected with lift rod 13, and lift rod 13 connects and establishes on lower pull rod 15, suspension controller 2 links to each other with electric hydraulic push rod 7, control panel 1, displacement sensor 3, force sensor 4, fast sensor 5 of wheel, radar tachometer sensor 6 through the cable respectively, the one end and the frame of electric hydraulic push rod 7 are articulated, and the other end is articulated with lift arm 12, displacement sensor 3 establishes in lift arm 12 corner, force sensor 4 connects and establishes in pull rod 15 department down, fast sensor 5 of wheel is connected and is established on the drive wheel, radar tachometer sensor 6 is located the automobile body.

Further, the suspension controller 2 is provided in the cab operation panel.

Further, motor 8, hydraulic pump 9, hydraulic pressure integrated valve group 10 connect gradually, pneumatic cylinder 11 is connected with hydraulic pressure integrated valve group 10, and pneumatic cylinder 11 and hydraulic pump 9 parallel arrangement.

Furthermore, the hydraulic integrated valve group 10 of the electro-hydraulic push rod 7 is composed of an electro-hydraulic reversing valve 16, a check valve 17, a hydraulic control check valve 18 and an overflow valve 19.

Furthermore, the ascending or descending of the agricultural implement is adjusted by changing the moving direction of a valve core of an electro-hydraulic reversing valve 16 of the electro-hydraulic push rod 7; the check valve 17 is used as a back pressure valve and plays a role of buffering to prevent the hydraulic oil from flowing back.

Furthermore, when the piston rod of the electro-hydraulic push rod 7 moves, the lifting arm 12 is driven to rotate around the lifting shaft, and the lifting of the agricultural implement is driven. When the piston rod of the electro-hydraulic push rod 6 moves, the lifting arm 12 is driven to rotate clockwise or anticlockwise around the lifting shaft, and the agricultural implement is driven to lift. The electro-hydraulic push rod hydraulic integrated valve group 10 comprises an electro-hydraulic reversing valve 16, a one-way valve 17, a hydraulic control one-way valve 18, an overflow valve 19 and the like. The ascending, descending or neutral of the agricultural implement can be adjusted by changing the moving direction of the valve core 16 of the electro-hydraulic reversing valve; the one-way valve 17 is used as a back pressure valve to ensure the stability of the return flow of the hydraulic oil; a hydraulic control one-way valve 18 is connected in series on the oil inlet and return paths of the hydraulic cylinder, when the motor 8 stops rotating, the hydraulic control one-way valve 18 is immediately closed, the hydraulic system is in a pressure maintaining state, and the agricultural implement can stop at any position of the stroke; when the system pressure exceeds the set pressure of the overflow valve 19, the hydraulic oil directly flows back to the oil tank through the overflow valve 19, and the motor 8 is always rotating but cannot be burnt, so that the overload of the motor 8 can be effectively avoided.

Further, the control method of the electric tractor suspension system based on the electro-hydraulic push rod comprises the following steps:

s1: a hydraulic control one-way valve 18 is connected in series on the oil inlet and return paths of the hydraulic cylinder 11, when the motor 8 stops rotating, the hydraulic control one-way valve 18 is immediately closed, the hydraulic system is in a pressure maintaining state, and the farm tool can stop at any position of the stroke;

s2: when the load of the suspension system exceeds the rated load, the motor 8 still runs, and when the pressure of the suspension system is higher than the set pressure of the overflow valve 19, hydraulic oil directly flows back to the oil tank through the overflow valve 19, so that the motor overload can be effectively avoided;

s3: the displacement parameters of the lifting arm 12 detected by the displacement sensor 3 are converted into the farming depth of the farm implement, the tension sensor 4 is used for detecting the soil resistance borne by the farm implement, and the slip rate of the electric tractor can be calculated by the rotating speed detected by the wheel speed sensor 5 and the vehicle speed detected by the radar speed measuring sensor 6;

s4: the proportion of one-position adjustment and force adjustment participating in tilling depth control is set in the suspension system, and the displacement parameters of the lifting arm 12 detected by the displacement sensor 3 are converted into the tilling depth H of the farm implement₁And is integrated with the soil resistance F detected by the tension sensor 4 by using an integration coefficient (H = aH)₁+ (1-a) F/β), outputting a tilling depth comprehensive control value H to realize force position comprehensive tilling depth adjustment, wherein a is the proportion of position adjustment participating in tilling depth control, 1-a is the proportion of force adjustment participating in tilling depth control, and β is soil specific resistance;

s5: the suspension system realizes force position-slip ratio comprehensive tilling depth adjustment, when the slip ratio is not in an optimal slip ratio interval, tilling depth control adopts slip ratio adjustment, and the suspension controller 2 sends a signal to enable the slip ratio to approach the optimal slip ratio interval by changing the tilling depth value; when the slip ratio is in the optimal slip ratio range, the tilling depth control adopts force position comprehensive regulation, and the suspension controller 2 sends out a signal to enable the actual tilling depth value to tend to the set tilling depth value.

The working principle of the electric tractor suspension system based on the electro-hydraulic push rod is as follows: before farming, a user sets a target tilling depth through the control panel 1 according to soil conditions and actual operation working conditions of the tractor, the displacement sensor 3, the tension sensor 4 and the wheel speed sensor 5 which are acquired by the suspension controller 2 during operation of the tractor are compared with a set target tilling depth signal after signal processing of the radar speed measuring sensor 6, then an output signal is calculated, and the electro-hydraulic push rod 7 is controlled to operate to drive the suspension mechanism to lift. When the farm tool needs to be lifted, the suspension controller 2 sends a signal to enable the valve core of the electro-hydraulic directional valve 16 to move to the left, hydraulic oil of the hydraulic pump 9 flows to the rodless cavity of the hydraulic cylinder 11 through the electro-hydraulic directional valve 16, and the piston rod moves to the right to drive the farm tool to lift; when the farm tool needs to descend, the suspension controller sends a signal to enable the valve core of the electro-hydraulic directional valve 16 to move to the right, hydraulic oil of the hydraulic pump 9 flows to the rod cavity of the hydraulic cylinder 11 through the electro-hydraulic directional valve 16, and the piston rod moves to the left to drive the farm tool to descend; when the farm tool needs to be centered, the suspension controller 1 sends a signal to enable the valve core of the electro-hydraulic reversing valve 16 to move to the middle position, the hydraulic system maintains pressure, the hydraulic pump 9 is not unloaded, and the hydraulic cylinder 11 is locked.

The suspension system of the electric tractor adopts force position-slip ratio comprehensive tilling depth adjustment, when the slip ratio is detected not to be in the optimal slip ratio interval, tilling depth control adopts slip ratio adjustment, and at the moment, the suspension controller 2 sends a signal to enable the slip ratio to approach the optimal slip ratio interval by changing the tilling depth value; when the slip ratio is detected to be in the optimal slip ratio range, the tilling depth is controlled by adopting force position comprehensive regulation, and the suspension controller 2 sends a signal to enable the actual tilling depth value to tend to the set tilling depth value.

The tilling depth adjusting process comprises the following steps:

step one, detecting the real-time slip rate, judging whether the slip rate is within an optimal slip rate interval (0.10-0.15), and if so, entering a step three; if not, entering the step two;

step two, judging whether the actual slip ratio is smaller than the optimal slip ratio interval, if so, driving the farm tool to descend by the electro-hydraulic push rod 7; if not, the electro-hydraulic push rod drives the farm tool to descend;

step three, judging whether the actual tilling depth value is smaller than the set tilling depth value, if so, driving the farm tool to descend by the electro-hydraulic push rod 7; if not, the electro-hydraulic push rod 7 drives the farm tool to ascend.

In conclusion, the electric tractor suspension system based on the electro-hydraulic push rod and the control method thereof have the advantages that the tillage depth control of the electric tractor suspension system adopts force position-slip ratio comprehensive adjustment, and the operation quality and the operation efficiency of the electric tractor are improved. The electric suspension device of the electric tractor overcomes the problems that the existing electric suspension device of the electric tractor has poor impact resistance strength, serious abrasion of a mechanism structure, high failure rate and the like in the actual working process, and influences the operation quality and the operation efficiency of the tractor when the change of the slip ratio of the tractor is large.

The principal features, principles and advantages of the invention have been shown and described above. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to explain the principles of the invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the invention as expressed in the following claims. The scope of the invention is defined by the appended claims and equivalents thereof.