A method and system for controlling the bale density of a square baler

Abstract

The present invention relates to a method and a system for controlling the bale density of a square bale baler, and relates to the field of density control of balers. The method includes: if at least one of the left pressure value and the right pressure value is less than the first pressure value, determining the target pressure value P2; increasing the oil inlet pressure of the oil inlet pipeline to the target pressure value P2, and supplying oil to the density oil cylinders with pressure values less than the first pressure value, so that both the left density oil cylinder and the right density oil cylinder apply pressure to the material with the target density control pressure value F0. The electro-hydraulic control system for bale density is used to implement the above method. The beneficial effects are as follows: the left pressure value FLe of the left density oil cylinder and the right pressure value FRi of the right density oil cylinder are independently detected, so as to detect the compression forces on the left and right sides of the bale in real time, independently control the pressure of the density oil cylinders, with high control accuracy, realize arbitrary adjustment of the target bale or forage density, improve the uniformity and appearance quality of the bale density, and have low equipment cost.

Description

Technical Field

[0001] The present invention relates to the field of density control of balers, and particularly to a method and a system for controlling the density of square bales of hay balers. Background Art

[0002] The control of bale density is one of the key technologies of square bale balers. Increasing the bale density can effectively reduce transportation and storage costs, slow down the loss rate of nutritional components, and greatly reduce the possibility of bales catching fire.

[0003] Currently, square bale density control systems are all designed based on the open compression theory. The reciprocating motion of the piston is driven by a crank - connecting rod mechanism to compress the forage into bales. At the same time, the position of the side wall of the compression chamber is controlled by a density oil cylinder, so as to adjust the cross - sectional area of the compression chamber. When the density oil cylinder contracts, the area of the compression chamber decreases. The bale bears a certain frictional force generated by the side wall of the compression chamber during the movement process, and the magnitude of this frictional force directly affects the bale density. The greater the output pressure of the density oil cylinder, the greater the frictional force on the bale, and the higher the bale density. Therefore, by controlling the oil pressure in the working chamber of the density oil cylinder, the adjustment of the bale density can be achieved.

[0004] The existing bale density adjustment and control hydraulic system uses the load of the compression chamber piston as the control quantity, and realizes the pressure control of the rod - end chamber of the density oil cylinder through a boost electromagnetic directional control valve and a step - down electromagnetic directional control valve to achieve the purpose of bale density control. However, the cost of the piston load detection equipment is high, and the existing hydraulic systems all control two density oil cylinders simultaneously, lacking the function and control method for separately detecting and controlling the pressure of the rod - end chambers of the two density oil cylinders, resulting in low control accuracy. Summary of the Invention

[0005] The technical problem to be solved by the present invention is how to reduce equipment costs and improve control accuracy.

[0006] The technical solution of the present invention for solving the above - mentioned technical problem is as follows: A method for controlling the density of square bales of hay balers, the method is applied to a bale density electro - hydraulic control system, the bale density electro - hydraulic control system includes a controller, a left density oil cylinder and a right density oil cylinder that are communicatively connected to the controller, hydraulic oil enters the left density oil cylinder and the right density oil cylinder through an oil inlet pipeline, and the bale density electro - hydraulic control system is used to bale the material through the left density oil cylinder and the right density oil cylinder during the process of controlling the oil inlet pressure of the oil inlet pipeline by the controller;

[0007] The method includes the following steps:

[0008] Step 1, obtain the left pressure value FLe exerted by the left density oil cylinder on the material, the right pressure value FRi exerted by the right density oil cylinder on the material, and the target density control pressure value F0, where the target density control pressure value F0 is not less than the first pressure value F0min and not greater than the second pressure value F0max;

[0009] Step 2, if at least one of the left pressure value FLe and the right pressure value FRi is less than the first pressure value F0min, then determine the target pressure value P2 according to the first pressure value F0min, the second pressure value F0max, the left pressure value FLe, and the right pressure value FRi;

[0010] Step 3, increase the oil inlet pressure of the oil inlet pipeline to the target pressure value P2, and supply oil to the density oil cylinder with a pressure value less than the first pressure value F0min, so that both the left density oil cylinder and the right density oil cylinder apply pressure to the material with the target density control pressure value F0.

[0011] The beneficial effects of the present invention are as follows: The left pressure value FLe of the left density oil cylinder and the right pressure value FRi of the right density oil cylinder are independently detected, so as to detect the compression force on the left and right sides of the bale in real time, and the difference in the compaction degree of the left and right parts of the bale can be identified. And the oil inlet pressure can be adjusted according to the left pressure value FLe and the right pressure value FRi, and the pressure of the density oil cylinder can be independently controlled to ensure that both the left pressure value FLe and the right pressure value FRi meet the requirements of the target density control pressure value F0, with high control accuracy, realizing arbitrary adjustment of the target bale or forage density, and improving the uniformity and appearance quality of the bale density. Detecting the pressure value only needs to be realized through a force sensor, and the equipment cost is low.

[0012] On the basis of the above technical solution, the present invention can also be improved as follows.

[0013] Further, in the step 2, determining the target pressure value P2 according to the first pressure value F0min, the second pressure value F0max, the left pressure value FLe, and the right pressure value FRi is specifically as follows:

[0014] Determine the first pressure difference ΔFLe according to the first pressure value F0min and the left pressure value FLe;

[0015] Determine the second pressure difference ΔFRi according to the first pressure value F0min and the right pressure value FRi;

[0016] Determine the target pressure value P2 according to the first pressure difference ΔFLe, the second pressure difference ΔFRi, the first pressure value F0min, and the second pressure value F0max through the first formula, where the first formula is:

[0017] P2 = (F0min + MAX(ΔFLe, ΔFRi) + C * (F0max - F0min)) * A

[0018] Wherein, A is the effective area of the rod chamber of the left density oil cylinder or the right density oil cylinder, C is the response coefficient, and 0 ≤ C < 1.

[0019] The beneficial effect of adopting the above further solution is that the target pressure value P2 obtained according to the first formula makes the left pressure value FLe of the left density oil cylinder and the right pressure value FRi of the right density oil cylinder always higher than the required first pressure value F0min by a certain value. The density oil cylinder can maintain pressure for a period of time without frequently replenishing hydraulic oil into the density oil cylinder, achieving energy conservation.

[0020] Further, step 2 further includes: if at least one of the left pressure value FLe and the right pressure value FRi is greater than the second pressure value F0max, correspondingly control the rod chamber of the left density oil cylinder to discharge hydraulic oil, and / or control the rod chamber of the right density oil cylinder to discharge hydraulic oil, so that both the left pressure value FLe and the right pressure value FRi are not greater than the second pressure value F0max.

[0021] Further, the method further includes:

[0022] Obtain the measured left oil pressure value PLe of the rod chamber of the left density oil cylinder and the measured right oil pressure value PRi of the rod chamber of the right density oil cylinder;

[0023] If at least one of the measured left oil pressure value PLe and the measured right oil pressure value PRi is greater than the maximum allowable oil pressure value of the bale density electro-hydraulic control system, correspondingly control the rod chamber of the left density oil cylinder to discharge hydraulic oil, and / or control the rod chamber of the right density oil cylinder to discharge hydraulic oil, so that both the measured left oil pressure value PLe and the measured right oil pressure value PRi are not greater than the maximum allowable oil pressure value.

[0024] Further, the method further includes:

[0025] After the material is compressed a set number of times, obtain a new left pressure value and a new right pressure value to adjust the inlet oil pressure of the inlet oil pipeline according to the new left pressure value and the new right pressure value.

[0026] The beneficial effect of adopting the above further solution is that the inlet oil pressure is adjusted according to the real-time right pressure value and left pressure value, and the control accuracy is high.

[0027] Further, the method further includes:

[0028] Determine a third pressure difference ΔF according to the left pressure value FLe and the right pressure value FRi;

[0029] If ΔF > ΔF0, an alarm message for increasing the right feeding amount of the pick-up of the baler is generated, where ΔF0 is the maximum allowable difference of the bale density electro-hydraulic control system;

[0030] If ΔF < -ΔF0, an alarm message for increasing the left feeding amount of the pick-up is generated.

[0031] The beneficial effect of adopting the above further solution is that the third pressure difference ΔF is within the maximum allowable difference range, the difference in the left and right compression forces on the bale is small, the bale density is more uniform, and the shape is more regular. During the operation, the alarm message prompts the driver to make real-time adjustments to the baler.

[0032] Further, the method further includes:

[0033] Obtaining the moisture content difference between the maximum moisture content and the minimum moisture content of the material within a preset time;

[0034] If the moisture content difference is greater than the preset moisture content difference, an alarm message for adjusting the feeding amount of the pick-up is generated.

[0035] The beneficial effect of adopting the above further solution is that when the moisture content of the material changes too much, it prompts the driver to increase or decrease the feeding amount of the pick-up.

[0036] Further, the method further includes:

[0037] Obtaining the traveling speed and the maximum limit speed of the baler;

[0038] If the traveling speed of the baler is higher than the maximum limit speed, an alarm prompt for deceleration is generated.

[0039] The beneficial effect of adopting the above further solution is that if the traveling speed of the baler is too fast, it prompts the driver to decelerate.

[0040] The present invention also provides a bale density electro-hydraulic control system for a rectangular bale baler, which is used to implement the bale density control method of the rectangular bale baler, including a controller, and a left density oil cylinder and a right density oil cylinder communicatively connected to the controller. Hydraulic oil enters the left density oil cylinder and the right density oil cylinder through an oil inlet pipeline. The bale density electro-hydraulic control system is used to realize the baling of the material through the left density oil cylinder and the right density oil cylinder during the process of controlling the oil inlet pressure of the oil inlet pipeline by the controller; the controller is used to execute the step 1 to the step 3.

[0041] Further, it further includes a left force sensor, a left pressure reducing solenoid valve, a right pressure reducing solenoid valve, a release solenoid valve, a boosting solenoid valve, an electro-hydraulic proportional relief valve, a hydraulic pump, a right force sensor and an oil return pipeline,

[0042] The left force sensor is fixed on the piston rod of the left density oil cylinder and is used to obtain the left pressure value FLe; the right force sensor is fixed on the piston rod of the right density oil cylinder and is used to obtain the right pressure value FRi;

[0043] One end of the oil inlet pipeline is communicated with the outlet of the hydraulic pump. The inlet and outlet of the electro-hydraulic proportional relief valve are respectively communicated with the oil inlet pipeline and the oil return pipeline. The other end of the oil inlet pipeline is respectively communicated with the oil inlet of the release solenoid valve and the oil inlet of the boost solenoid valve. The oil return ports of the release solenoid valve and the boost solenoid valve are both communicated with the oil return pipeline. The working port of the release solenoid valve is respectively communicated with the rodless cavity of the left density oil cylinder and the rodless cavity of the right density oil cylinder. The working port of the boost solenoid valve is respectively communicated with the first oil port of the left pressure reducing solenoid valve and the first oil port of the right pressure reducing solenoid valve. The second oil port of the left pressure reducing solenoid valve is communicated with the rod chamber of the left density oil cylinder. The second oil port of the right pressure reducing solenoid valve is communicated with the rod chamber of the right density oil cylinder.

[0044] The working port of the release solenoid valve is communicated with its oil inlet or its oil return port. The working port of the boost solenoid valve is communicated with its oil inlet or its oil return port. The first oil port of the left pressure reducing solenoid valve is communicated with its second oil port or is in a two-way cut-off state. The first oil port of the right pressure reducing solenoid valve is communicated with its second oil port or is in a two-way cut-off state.

[0045] The controller is respectively in communication connection with the left pressure reducing solenoid valve, the right pressure reducing solenoid valve, the release solenoid valve, the boost solenoid valve, the electro-hydraulic proportional relief valve, the left force sensor and the right force sensor.

[0046] The beneficial effects of adopting the above further scheme are as follows: The pressure values of the left density oil cylinder and the right density oil cylinder can be respectively controlled by the left pressure reducing solenoid valve and the right pressure reducing solenoid valve. The overflow pressure can be adjusted through the electro-hydraulic proportional relief valve, so as to control the oil inlet pressure of the oil inlet pipeline. Description of the Drawings

[0047] Figure 1 is the schematic diagram of the electro-hydraulic control system for the bale density of the square bale baler of the present invention;

[0048] Figure 2 is the flow chart of the method for controlling the bale density of the square bale baler of the present invention.

[0049] In the drawings, the list of components represented by each reference numeral is as follows:

[0050] 1. Left force sensor; 2. Left density oil cylinder; 3. Left pressure reducing solenoid valve; 4. Right pressure reducing solenoid valve; 5. Release solenoid valve; 6. Boost solenoid valve; 7. Safety valve; 8. Electro-hydraulic proportional relief valve; 9. Hydraulic pump; 10. Hydraulic oil tank; 11. Return oil filter; 12. Moisture content detection device; 13. Vehicle speed sensor; 14. Controller; 15. Right oil pressure sensor; 16. Left oil pressure sensor; 17. Right density oil cylinder; 18. Right force sensor. Detailed implementation mode

[0051] The principles and features of the present invention will be described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0052] Embodiment 1

[0053] As Figure 1 shown, the present invention also provides an electro-hydraulic control system for the bale density of a square bale baler, which is used to implement the method for controlling the bale density of a square bale baler, including a controller 14, and a left density oil cylinder 2 and a right density oil cylinder 17 that are communicatively connected to the controller 14. Hydraulic oil enters the left density oil cylinder 2 and the right density oil cylinder 17 through an oil inlet pipeline. The electro-hydraulic control system for the bale density is used to realize the baling of materials through the left density oil cylinder 2 and the right density oil cylinder 17 during the process of controlling the oil inlet pressure of the oil inlet pipeline by the controller 14; the controller 14 is used to execute steps 1 to 3.

[0054] Furthermore, it further includes a left force sensor 1, a left pressure reducing solenoid valve 3, a right pressure reducing solenoid valve 4, a release solenoid valve 5, a boost solenoid valve 6, an electro-hydraulic proportional relief valve 8, a hydraulic pump 9, a right force sensor 18 and a return oil pipeline.

[0055] The left force sensor 1 is fixed on the piston rod of the left density oil cylinder 2 and is used to obtain the left pressure value FLe; the right force sensor 18 is fixed on the piston rod of the right density oil cylinder 17 and is used to obtain the right pressure value FRi.

[0056] One end of the oil inlet pipeline is communicated with the outlet of the hydraulic pump 9. The inlet and outlet of the electro-hydraulic proportional relief valve 8 are respectively communicated with the oil inlet pipeline and the oil return pipeline. The other end of the oil inlet pipeline is respectively communicated with the oil inlet of the release solenoid valve 5 and the oil inlet of the boosting solenoid valve 6. The oil return ports of the release solenoid valve 5 and the boosting solenoid valve 6 are both communicated with the oil return pipeline. The working port of the release solenoid valve 5 is respectively communicated with the rodless cavities of the left density cylinder 2 and the right density cylinder 17. The working port of the boosting solenoid valve 6 is respectively communicated with the first oil ports of the left pressure reducing solenoid valve 3 and the right pressure reducing solenoid valve 4. The second oil port of the left pressure reducing solenoid valve 3 is communicated with the rod chamber of the left density cylinder 2. The second oil port of the right pressure reducing solenoid valve 4 is communicated with the rod chamber of the right density cylinder 17.

[0057] The working port of the release solenoid valve 5 is communicated with its oil inlet or its oil return port. The working port of the boosting solenoid valve 6 is communicated with its oil inlet or its oil return port. The first oil port of the left pressure reducing solenoid valve 3 is communicated with its second oil port or is in two-way cut-off. The first oil port of the right pressure reducing solenoid valve 4 is communicated with its second oil port or is in two-way cut-off.

[0058] The controller 14 is respectively in communication connection with the left pressure reducing solenoid valve 3, the right pressure reducing solenoid valve 4, the release solenoid valve 5, the boosting solenoid valve 6, the electro-hydraulic proportional relief valve 8, the left side force sensor 1 and the right side force sensor 18.

[0059] In this solution, the left pressure reducing solenoid valve 3 and the right pressure reducing solenoid valve 4 can respectively control the pressure values of the left density cylinder 2 and the right density cylinder 17. The electro-hydraulic proportional relief valve 8 can adjust the relief pressure, thereby controlling the oil inlet pressure of the oil inlet pipeline.

[0060] Further, a safety valve 7 is further included. The inlet and outlet of the safety valve 7 are respectively communicated with the oil inlet pipeline and the oil return pipeline. The safety valve 7 is used to ensure that the oil pressure of the hydraulic system does not exceed the maximum working pressure of the system.

[0061] Further, the inlet of the hydraulic pump 9 is communicated with the hydraulic oil tank 10. The oil return pipeline is communicated with the hydraulic oil tank 10 through an oil return filter 11.

[0062] Further, a moisture content detection device 12 for detecting the moisture content of the material and a vehicle speed sensor 13 for detecting the traveling speed of the baler are further included. The controller 14 is respectively in communication connection with the moisture content detection device 12 and the vehicle speed sensor 13, and receives the detected material moisture content information and the baler traveling speed information.

[0063] Further, it also includes a left oil pressure sensor 16 for detecting the measured left oil pressure value PLe of the rod chamber of the left density oil cylinder 2, and a right oil pressure sensor 15 for detecting the measured right oil pressure value PRi of the rod chamber of the right density oil cylinder 17. The controller 14 is communicatively connected to the left oil pressure sensor 16 and the right oil pressure sensor 15 respectively, and receives the detected measured left oil pressure value PLe and measured right oil pressure value PRi.

[0064] Optionally, the left pressure reducing solenoid valve 3 and the right pressure reducing solenoid valve 4 may both have a manual override function. That is to say, during the process of being controlled and switched by the controller 14, the left pressure reducing solenoid valve 3 and the right pressure reducing solenoid valve 4 can be switched manually.

[0065] The front end of the baler picks up straw or forage through a pick-up, and the piston in the baling chamber reciprocates back and forth to convey the material into the compression chamber of the baling mechanism and compress it into a bale. The left density oil cylinder 2 and the right density oil cylinder 17 control the position of the side wall of the compression chamber, thereby adjusting the cross-sectional area of the compression chamber. When the density oil cylinder contracts, the area of the compression chamber decreases, and the pressure on the material increases, thereby increasing the density; conversely, when the density oil cylinder extends, the pressure on the material decreases. The square bale baler straw bale density electro-hydraulic control system is arranged on the baler and is used to control the density of baling by the baling mechanism.

[0066] The working principle of the square bale baler straw bale density electro-hydraulic control system is as follows:

[0067] In one specific example, as Figure 1 shows the states when each solenoid valve is de-energized, that is, the working port of the release solenoid valve 5 is communicated with its oil return port, the working port of the boost solenoid valve 6 is communicated with its oil return port, the first oil port of the left pressure reducing solenoid valve 3 is bidirectionally blocked from its second oil port, and the first oil port of the right pressure reducing solenoid valve 4 is bidirectionally blocked from its second oil port. Of course, the valve positions in the energized and de-energized states of each solenoid valve can be interchanged. For example, when de-energized, the working port of the release solenoid valve 5 is communicated with its oil inlet port. The following description of the working process is based on the Figure 1 shown solenoid valve states as an example.

[0068] Boosting process: When the left pressure value FLe and / or the right pressure value FRi is less than the first pressure value F0min, the release solenoid valve 5 is de-energized, the boost solenoid valve 6 is energized, the controller 14 controls the overflow pressure of the electro-hydraulic proportional overflow valve 8 to quickly increase the inlet oil pressure of the inlet pipeline to the target pressure value P2, and the left pressure reducing solenoid valve 3 and / or the right pressure reducing solenoid valve 4 is energized, so that the hydraulic oil enters the left density oil cylinder 2 and / or the right density oil cylinder 17 with insufficient pressure values to achieve boost control, so that both the left density oil cylinder 2 and the right density oil cylinder 17 apply pressure to the material with the target density control pressure value F0.

[0069] Pressure holding process: After the pressure boosting is completed, both the left pressure reducing solenoid valve 3 and the right pressure reducing solenoid valve 4 lose power, and the rod chambers of the left density oil cylinder 2 and the right density oil cylinder 17 hold pressure.

[0070] Pressure reducing process: If at least one of the measured left oil pressure value PLe and the measured right oil pressure value PRi is greater than the maximum allowable oil pressure value of the bale density electro-hydraulic control system, or at least one of the left pressure value FLe and the right pressure value FRi is greater than the second pressure value F0max, then the release solenoid valve 5 is de-energized, the corresponding left pressure reducing solenoid valve 3 or right pressure reducing solenoid valve 4 is energized, and the pressure boosting solenoid valve 6 is de-energized. The hydraulic oil in the rod chambers of the density oil cylinders can flow back to the hydraulic oil tank 10 through the corresponding pressure reducing solenoid valves and the pressure boosting solenoid valve 6 until both the left pressure value FLe and the right pressure value FRi are between the first pressure value F0min and the second pressure value F0max.

[0071] Release process: When baling is completed and the bale needs to be released, the left pressure reducing solenoid valve 3, the right pressure reducing solenoid valve 4, and the release solenoid valve 5 are energized, and the pressure boosting solenoid valve 6 is de-energized. The controller 14 controls the inlet pressure of the electro-hydraulic proportional relief valve 8 to gradually increase and maintain at a pressure P1 sufficient to extend the piston rods of the left density oil cylinder 2 and the right density oil cylinder 17. The rodless chambers of the left density oil cylinder 2 and the right density oil cylinder 17 are filled with oil, and the piston rods of the left density oil cylinder 2 and the right density oil cylinder 17 extend to release the pressure in the compression chamber and prepare for pushing out the last bale.

[0072] When one of the left pressure value FLe and the right pressure value Fri is less than the first pressure value F0min and the other is greater than the second pressure value F0max, first perform pressure reducing control on the density oil cylinder with a pressure value greater than the second pressure value F0max, and then perform pressure boosting control on the density oil cylinder with a pressure value less than the first pressure value F0min.

[0073] Embodiment 2

[0074] As Figure 2 shown, this embodiment provides a method for controlling the bale density of a square bale baler. The method is applied to a bale density electro-hydraulic control system, which includes a controller 14, and a left density oil cylinder 2 and a right density oil cylinder 17 communicatively connected to the controller 14. Hydraulic oil enters the left density oil cylinder 2 and the right density oil cylinder 17 through an oil inlet pipeline. The bale density electro-hydraulic control system is used to bale materials through the left density oil cylinder 2 and the right density oil cylinder 17 while controlling the inlet oil pressure of the oil inlet pipeline through the controller 14;

[0075] The method includes the following steps:

[0076] Step 1, obtain the left pressure value FLe exerted by the left density oil cylinder 2 on the material, the right pressure value FRi exerted by the right density oil cylinder 17 on the material, and the target density control pressure value F0, where the target density control pressure value F0 is not less than the first pressure value F0min and not greater than the second pressure value F0max;

[0077] Step 2, if at least one of the left pressure value FLe and the right pressure value FRi is less than the first pressure value F0min, then determine the target pressure value P2 according to the first pressure value F0min, the second pressure value F0max, the left pressure value FLe, and the right pressure value FRi;

[0078] Step 3, increase the oil inlet pressure of the oil inlet pipeline to the target pressure value P2, and supply oil to the density oil cylinder with a pressure value less than the first pressure value F0min, so that both the left density oil cylinder 2 and the right density oil cylinder 17 exert pressure on the material with the target density control pressure value F0.

[0079] The left pressure value FLe of the left density oil cylinder 2 and the right pressure value FRi of the right density oil cylinder 17 are independently detected, so as to detect the compression force on the left and right sides of the bale in real time, and the difference in the compaction degree of the left and right parts of the bale can be identified. And the oil inlet pressure can be adjusted according to the left pressure value FLe and the right pressure value FRi, and the pressure of the density oil cylinder can be independently controlled to ensure that both the left pressure value FLe and the right pressure value FRi meet the requirements of the target density control pressure value F0, with high control accuracy, realizing arbitrary adjustment of the high and low density of the target bale or forage, improving the uniformity and appearance quality of the bale density. Detecting the pressure value only needs to be realized through a force sensor, and the equipment cost is low.

[0080] Specifically, the preset bale density value can be determined according to the selected type of straw or forage (such as rice and wheat straw, corn straw, alfalfa or natural forage, etc.), and through pre-tests or calculations, the bale density value is converted into the target density control pressure value F0 and stored.

[0081] Among them, in Step 3, it can be realized by adjusting the overflow pressure of the electro-hydraulic proportional relief valve 8 and switching the left pressure reducing solenoid valve 3, the right pressure reducing solenoid valve 4, and the pressure increasing solenoid valve 6.

[0082] Further, in Step 2, according to the first pressure value F0min, the second pressure value F0max, the left pressure value FLe, and the right pressure value FRi, determining the target pressure value P2 is specifically:

[0083] According to the first pressure value F0min and the left pressure value FLe, determine the first pressure difference ΔFLe; where, ΔFLe = F0min - FLe;

[0084] Determine a second pressure difference ΔFRi based on the first pressure value F0min and the right pressure value FRi; where ΔFRi = F0min - FRi;

[0085] Based on the first pressure difference ΔFLe, the second pressure difference ΔFRi, the first pressure value F0min, and the second pressure value F0max, determine the target pressure value P2 through a first formula, where the first formula is:

[0086] P2 = (F0min + MAX(ΔFLe, ΔFRi) + C * (F0max - F0min)) * A

[0087] Where A is the acting area of the rodless cavity of the left density oil cylinder 2 or the right density oil cylinder 17, and C is a response coefficient, 0 ≤ C < 1.

[0088] Where the acting areas of the rodless cavities of the left density oil cylinder 2 and the right density oil cylinder 17 are the same. C is a response coefficient set to improve the responsiveness of the bale density electro-hydraulic control system. The larger the value of C, the faster the system response.

[0089] In this solution, the target pressure value P2 obtained according to the first formula makes the left pressure value FLe of the left density oil cylinder 2 and the right pressure value FRi of the right density oil cylinder 17 always higher than the required first pressure value F0min by a certain value. The density oil cylinder can maintain pressure for a period of time without frequently replenishing hydraulic oil into the density oil cylinder, achieving energy conservation.

[0090] Further, step 2 further includes: If at least one of the left pressure value FLe and the right pressure value FRi is greater than the second pressure value F0max, correspondingly control the rodless cavity of the left density oil cylinder 2 to discharge hydraulic oil, and / or, the rodless cavity of the right density oil cylinder 17 to discharge hydraulic oil, so that both the left pressure value FLe and the right pressure value FRi are not greater than the second pressure value F0max.

[0091] Specifically, the corresponding control of the rodless cavity of the left density oil cylinder 2 to discharge hydraulic oil, and / or, the rodless cavity of the right density oil cylinder 17 to discharge hydraulic oil is achieved by controlling only the left pressure reducing solenoid valve 3 and / or the right pressure reducing solenoid valve 4 to be energized.

[0092] Further, the method further includes:

[0093] Obtain the measured left oil pressure value PLe of the rodless cavity of the left density oil cylinder 2 and the measured right oil pressure value PRi of the rodless cavity of the right density oil cylinder 17;

[0094] If at least one of the measured left oil pressure value PLe and the measured right oil pressure value PRi is greater than the maximum allowable oil pressure value of the bale density electro-hydraulic control system, the hydraulic oil in the rod chamber of the corresponding left density cylinder 2 is discharged, and / or, the hydraulic oil in the rod chamber of the right density cylinder 17 is discharged, so that both the measured left oil pressure value PLe and the measured right oil pressure value PRi are not greater than the maximum allowable oil pressure value.

[0095] Further, the method further includes:

[0096] After the material is compressed a set number of times, a new left pressure value and a new right pressure value are obtained to adjust the oil inlet pressure of the oil inlet pipeline according to the new left pressure value and the new right pressure value.

[0097] In this solution, the oil inlet pressure is adjusted according to the real-time right pressure value and left pressure value, and the control accuracy is high.

[0098] Specifically, the set number of times the material is compressed can be any number of times, for example, the set number of times is 1, 2, 3, 4 or 5 or more. Optionally, the set number of times can be 2-4 times. For example, in one specific example, the set number of times is 4 times, and the execution frequency of step 2 and step 3 is once every 4 times the material is compressed. Among them, the maximum pressure value exerted by the measured left density cylinder 2 on the material during each compression process is denoted as FLei, and the average value of multiple FLei for the set number of times is used as the left pressure value FLe, which is calculated once after the material is compressed the set number of times, and the new calculated value is used as the new left pressure value FLe; similarly, the maximum pressure value exerted by the measured right density cylinder 17 on the material during each compression process is denoted as FRi i, and the average value of multiple FRi i for the set number of times is used as the right pressure value FRi, which is calculated once after the material is compressed the set number of times, and the new calculated value is used as the new right pressure value FRi. For example, if steps 2 and 3 are executed once every 4 times the material is compressed, the left pressure value FLe obtained after the first four compressions is FLe=(FLe1 + FLe2 + FLe3 + FLe4) / 4.

[0099] Further, the method further includes:

[0100] According to the left pressure value FLe and the right pressure value FRi, a third pressure difference ΔF is determined; where ΔF = FLe - Fri;

[0101] If ΔF > ΔF0, an alarm message for increasing the right feeding amount of the pick-up of the baler is generated, where ΔF0 is the maximum allowable difference of the bale density electro-hydraulic control system;

[0102] If ΔF < -ΔF0, an alarm message for increasing the left feeding amount of the pick-up is generated.

[0103] This solution keeps the third pressure difference ΔF within the maximum allowable difference range, resulting in a small difference in the compression forces on the left and right sides of the bale, a more uniform bale density, and a more regular shape. During the operation, the alarm information prompts the driver to make real-time adjustments to the baler.

[0104] Optionally, the steps of determining the third pressure difference ΔF and generating alarm information based on ΔF and ΔF0 are executed after the material has been compressed a set number of times. The set number of times the material is compressed can be any number, such as 1, 2, 3, 4, or 5 or more. This step and steps 2 and 3 can be executed at the same compression count. For example, when the material is compressed for the 4th, 8th, and 12th times, steps 2 and 3 are executed, and the third pressure difference ΔF is determined and alarm information is generated based on ΔF and ΔF0; or, they can also be executed staggered at different compression counts. For example, when the material is compressed for the 4th, 8th, and 12th times, steps 2 and 3 are executed, and when the material is compressed for the 2nd, 6th, and 10th times, the third pressure difference ΔF is determined and alarm information is generated based on ΔF and ΔF0.

[0105] Furthermore, the method further includes:

[0106] Obtaining the moisture content difference between the maximum moisture content and the minimum moisture content of the material within a preset time;

[0107] If the moisture content difference is greater than the preset moisture content difference, an alarm message for adjusting the feeding amount of the pick-up is generated.

[0108] When the moisture content of the material changes too much, it prompts the driver to increase or decrease the feeding amount of the pick-up.

[0109] Furthermore, the method further includes:

[0110] Obtaining the traveling speed and the maximum limit speed of the baler;

[0111] If the traveling speed of the baler is higher than the maximum limit speed, an alarm prompt for deceleration is generated.

[0112] If the traveling speed of the baler is too fast, it prompts the driver to decelerate.

[0113] In the existing hydraulic system, an accumulator and a ball valve are usually configured, which makes the system complex. At the same time, it reduces the stiffness of the pressure in the rod chamber, resulting in a lower control accuracy of the bale density, a poorer system responsiveness, and a large energy loss. In this solution, there is no need to set an accumulator and a ball valve, which simplifies the system structure. The target pressure value P2 is determined by the first formula, and the oil pressures of the two density cylinders are controlled respectively, so that the control accuracy of the bale density is high. The system response speed can be adjusted by the response coefficient C, and the energy loss is low.

[0114] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0115] In several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the method embodiments described above are merely illustrative. For example, the division of steps is only a logical function division. In actual implementation, there may be other division methods. For example, multiple steps can be combined or integrated into another step, or some features can be ignored or not executed.

[0116] If the above method is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods of the various embodiments of the present invention. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0117] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A method for controlling the bale density of a square bale baler, characterized in that, the method is applied to a bale density electro-hydraulic control system, the bale density electro-hydraulic control system includes a controller (14), and a left density oil cylinder (2) and a right density oil cylinder (17) communicatively connected to the controller (14). Hydraulic oil enters the left density oil cylinder (2) and the right density oil cylinder (17) through an oil inlet pipeline. The bale density electro-hydraulic control system is used to realize baling of materials through the left density oil cylinder (2) and the right density oil cylinder (17) during the process of controlling the oil inlet pressure of the oil inlet pipeline by the controller (14); the method includes the following steps: Step 1, obtain the left pressure value FLe exerted by the left density oil cylinder (2) on the material, the right pressure value FRi exerted by the right density oil cylinder (17) on the material, and the target density control pressure value F0. The target density control pressure value F0 is not less than the first pressure value F0min and not greater than the second pressure value F0max; Step 2, if at least one of the left pressure value FLe and the right pressure value FRi is less than the first pressure value F0min, then determine the target pressure value P2 according to the first pressure value F0min, the second pressure value F0max, the left pressure value FLe and the right pressure value FRi; specifically: determine the first pressure difference ΔFLe according to the first pressure value F0min and the left pressure value FLe; determine the second pressure difference ΔFRi according to the first pressure value F0min and the right pressure value FRi; determine the target pressure value P2 through a first formula according to the first pressure difference ΔFLe, the second pressure difference ΔFRi, the first pressure value F0min and the second pressure value F0max, where the first formula is: P2 = (F0min + MAX(ΔFLe, ΔFRi) + C*(F0max - F0min)) / A where A is the effective area of the rodless cavity of the left density oil cylinder (2) or the right density oil cylinder (17), and C is a response coefficient, 0 ≤ C < 1; Step 3, increase the oil inlet pressure of the oil inlet pipeline to the target pressure value P2, and supply oil to the density oil cylinder with a pressure value less than the first pressure value F0min, so that both the left density oil cylinder (2) and the right density oil cylinder (17) apply pressure to the material with the target density control pressure value F0.

2. A method for controlling the bale density of a square bale baler according to claim 1, characterized in that, Step 2 further includes: if at least one of the left pressure value FLe and the right pressure value FRi is greater than the second pressure value F0max, then correspondingly control the rodless cavity of the left density oil cylinder (2) to discharge hydraulic oil, and / or, the rodless cavity of the right density oil cylinder (17) to discharge hydraulic oil, so that both the left pressure value FLe and the right pressure value FRi are not greater than the second pressure value F0max.

3. A method for controlling the bale density of a square bale baler according to any one of claims 1 to 2, It is characterized in that the method further includes: obtaining the measured left oil pressure value PLe of the rod chamber of the left density oil cylinder (2) and the measured right oil pressure value PRi of the rod chamber of the right density oil cylinder (17); if at least one of the measured left oil pressure value PLe and the measured right oil pressure value PRi is greater than the maximum allowable oil pressure value of the bale density electro-hydraulic control system, correspondingly controlling the discharge of hydraulic oil from the rod chamber of the left density oil cylinder (2), and / or, the discharge of hydraulic oil from the rod chamber of the right density oil cylinder (17), so that both the measured left oil pressure value PLe and the measured right oil pressure value PRi are not greater than the maximum allowable oil pressure value.

4. A method for controlling the bale density of a rectangular baler according to any one of claims 1-2, it is characterized in that the method further includes: after the material is compressed a set number of times, obtaining a new left pressure value and a new right pressure value, so as to adjust the oil inlet pressure of the oil inlet pipeline according to the new left pressure value and the new right pressure value.

5. A method for controlling the bale density of a rectangular baler according to any one of claims 1-2, it is characterized in that the method further includes: determining a third pressure difference ΔF according to the left pressure value FLe and the right pressure value FRi; if ΔF>ΔF0, generating an alarm message to increase the right feeding amount of the pick-up of the baler, where ΔF0 is the maximum allowable difference of the bale density electro-hydraulic control system; if ΔF<-ΔF0, generating an alarm message to increase the left feeding amount of the pick-up.

6. A method for controlling the bale density of a rectangular baler according to any one of claims 1-2, it is characterized in that the method further includes: obtaining the moisture content difference between the maximum moisture content value and the minimum moisture content value of the material within a preset time; if the moisture content difference is greater than the preset moisture content difference, generating an alarm message to adjust the feeding amount of the pick-up.

7. A method for controlling the bale density of a rectangular baler according to any one of claims 1-2, it is characterized in that the method further includes: obtaining the traveling speed and the maximum limit speed of the baler; if the traveling speed of the baler is higher than the maximum limit speed, generating an alarm prompt for deceleration.

8. A bale density electro-hydraulic control system for a rectangular baler, it is characterized in that used to implement the method for controlling the bale density of a rectangular baler according to any one of claims 1-7, including a controller (14), and a left density oil cylinder (2) and a right density oil cylinder (17) communicatively connected to the controller (14), hydraulic oil enters the left density oil cylinder (2) and the right density oil cylinder (17) through an oil inlet pipeline, and the bale density electro-hydraulic control system is used to realize the baling of materials through the left density oil cylinder (2) and the right density oil cylinder (17) during the process of controlling the oil inlet pressure of the oil inlet pipeline by the controller (14); the controller (14) is used to execute the steps 1 to 3.

9. A bale density electro-hydraulic control system for a rectangular baler according to claim 8, it is characterized in that It also includes a left force sensor (1), a left step-down solenoid valve (3), a right step-down solenoid valve (4), a release solenoid valve (5), a boost solenoid valve (6), an electro-hydraulic proportional relief valve (8), a hydraulic pump (9), a right force sensor (18) and an oil return line. The left force sensor (1) is fixed on the piston rod of the left density oil cylinder (2) and is used to obtain the left pressure value FLe; the right force sensor (18) is fixed on the piston rod of the right density oil cylinder (17) and is used to obtain the right pressure value FRi. One end of the oil inlet line is communicated with the outlet of the hydraulic pump (9), the inlet and outlet of the electro-hydraulic proportional relief valve (8) are respectively communicated with the oil inlet line and the oil return line, the other end of the oil inlet line is respectively communicated with the oil inlet of the release solenoid valve (5) and the oil inlet of the boost solenoid valve (6), the oil return ports of the release solenoid valve (5) and the boost solenoid valve (6) are both communicated with the oil return line, the working port of the release solenoid valve (5) is respectively communicated with the rodless cavity of the left density oil cylinder (2) and the rodless cavity of the right density oil cylinder (17), the working port of the boost solenoid valve (6) is respectively communicated with the first oil port of the left step-down solenoid valve (3) and the first oil port of the right step-down solenoid valve (4), the second oil port of the left step-down solenoid valve (3) is communicated with the rod chamber of the left density oil cylinder (2), and the second oil port of the right step-down solenoid valve (4) is communicated with the rod chamber of the right density oil cylinder (17). The working port of the release solenoid valve (5) is communicated with its oil inlet or its oil return port, the working port of the boost solenoid valve (6) is communicated with its oil inlet or its oil return port, the first oil port of the left step-down solenoid valve (3) is communicated with its second oil port or is in a double-block state, and the first oil port of the right step-down solenoid valve (4) is communicated with its second oil port or is in a double-block state. The controller (14) is respectively in communication connection with the left step-down solenoid valve (3), the right step-down solenoid valve (4), the release solenoid valve (5), the boost solenoid valve (6), the electro-hydraulic proportional relief valve (8), the left force sensor (1) and the right force sensor (18).

Images