A tractor implement control method, system and tractor

Abstract

The application discloses a tractor implement control method, system and tractor in the technical field of tractor implement control. The method comprises the following steps: receiving a lowering speed setting value; converting the lowering speed setting value into a control current of a lowering control valve according to a set control strategy, and outputting the control current to the lowering control valve, wherein the set control strategy considers current compensation caused by temperature change and load compensation caused by implement load change, so as to realize stable lowering control of the tractor implement. The application solves the problem of stop impact caused by implement load change and temperature change in the process of lowering the tractor implement by using a fixed deceleration interval.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of tractor implement control, and particularly relates to a tractor implement control method and system and a tractor. BACKGROUND

[0002] As a power platform, the tractor is adapted to different implements through a rear suspension to realize different forms of field operation requirements. Different operation implements are usually provided with different lowering speed requirements. The control of the rear suspension mainly includes mechanical suspension and electro-hydraulic control suspension. The mechanical suspension usually adopts a mechanical handle, a connecting flexible shaft and a manual control valve to control the oil liquid on-off to the suspension system to realize the lifting and lowering of the implement. For the electro-hydraulic control suspension, the controller controls an electric proportional valve according to a control strategy to realize the lifting or lowering of the implement through the functions of the lifting button and the lowering button on the control panel.

[0003] For the electro-hydraulic control rear suspension system, the controller needs to be connected with input and output. The current output of the controller is basically in the form of PWM duty ratio, different currents are output, some controllers have a current detection loop, can perform current feedback and current PID adjustment to make the output current consistent with the requested current, and some high-end controllers are provided with an independent PID current closed-loop adjustment chip to perform requested current closed-loop output adjustment.

[0004] The electro-hydraulic control rear suspension system has the following problems in the implement action process.

[0005] (1) For the implement lowering process, the weights of different implements are different, so the lowering speed is different under the same valve opening, that is, the actual speed changes under the same lowering speed parameter setting, the original set deceleration buffer interval cannot meet the speed adjustment buffer requirement, the speed suddenly changes in the process, causing the stop impact problem;

[0006] (2) Some controllers have a current detection loop for PID current adjustment, but the detection current feedback response is slow, especially when the requested current suddenly changes, the controller cannot respond in time, the time required for stable current is long, and the current setting of the control process is affected; the controller with an independent PID current adjustment chip can quickly detect the current and respond to the output requested current in time, but an independent chip needs to be set, and the cost of the controller is obviously increased;

[0007] (3) The controller outputs current in the form of PWM duty ratio, when the temperature changes, the resistance value changes due to the temperature influence on the electromagnetic valve resistance and other parameters, the controller has the same set requested value, different control currents are formed at the electromagnetic valve, the implement is faster or slower in the set corresponding deceleration interval, the speed changes, and the original set deceleration buffer interval cannot meet the influence of the current change caused by the temperature change. SUMMARY

[0008] In order to solve the problems in the prior art, the tractor implement control method, system and tractor are provided to solve the stop impact problem caused by the fixed reduction interval and the changes of the implement load and the solenoid temperature during the descent of the tractor implement.

[0009] To achieve the above object, the technical scheme adopted by the present application is:

[0010] In a first aspect, a tractor implement control method is provided, comprising: receiving a descent speed setting value; converting the descent speed setting value into a control current of a descent control valve according to a set control strategy, and outputting to the descent control valve for realizing stable descent control of the tractor implement.

[0011] Further, the set control strategy comprises: setting a reduction buffer interval according to the descent speed setting value; when the tractor implement reaches the upper limit of the reduction buffer interval, starting to reduce the control current of the descent control valve for reducing the descent speed of the tractor implement; when the tractor implement reaches the lower limit of the reduction buffer interval, the control current of the descent control valve is reduced to a first target current and directly returns to zero at the first target current.

[0012] Further, the set control strategy comprises: setting a reduction buffer interval according to the descent speed setting value, and setting a first reduction point between the upper limit of the reduction buffer interval and the lower limit of the reduction buffer interval; when the tractor implement reaches the upper limit of the reduction buffer interval, starting to reduce the control current of the descent control valve for reducing the descent speed of the tractor implement; when the tractor implement reaches the first reduction point, the control current of the descent control valve is reduced to a first reduction point current, and directly reduced to a first target current from the first reduction point current, and maintained at the first target current until the tractor implement descends to the lower limit of the reduction buffer interval; when the tractor implement reaches the lower limit of the reduction buffer interval, the control current of the descent control valve directly returns to zero from the first target current.

[0013] Further, the control current output to the descent control valve is a current after temperature compensation; the temperature compensation method comprises: the controller controls the corresponding current output to the descent control valve according to the descent speed setting value, when the controller pre-output current reaches the set current size, the controller collects the control current received by the descent control valve in real time; calculating the difference between the control current received by the descent control valve and the control current pre-output by the controller, when the difference exceeds the set threshold, the difference is added to the control current output by the controller as the control current output by the controller at the next moment.

[0014] Further, the difference value is superimposed on the control current output by the controller, specifically: when the actual current E1 received by the descending control valve is greater than the control current M pre-output by the controller according to the descending speed setting value, the difference value Δ1=E1-M is calculated; before the tractor implement enters the deceleration buffer interval, the difference value Δ1 is subtracted from the control current M pre-output by the controller, as the control current output by the controller at the next moment; meanwhile, the first target current is compensated, and half of the difference value Δ1 is subtracted from the first target current, as the new first target current; when the actual current E2 received by the descending control valve is less than the control current M pre-output by the controller according to the descending speed setting value, the difference value Δ2=M-E2 is calculated; before the tractor implement enters the deceleration buffer interval, the difference value Δ2 is added to the control current M output by the controller, as the control current output by the controller at the next moment; meanwhile, the first target current is compensated, and half of the difference value Δ2 is added to the first target current, as the new first target current.

[0015] Further, a reference implement is set, and the force value of the reference implement acting on the force sensor is defined as a reference force value; whether the load of the tractor implement changes is judged according to the reference force value; when the load of the tractor implement changes, implement load change load compensation is performed.

[0016] Further, the method for judging whether the load of the tractor implement changes according to the reference force value comprises: collecting the force value G2 of the implement currently used by the tractor acting on the force sensor at a set position; setting k 力值 =G2 / G1, wherein G1 is the force value of the reference implement acting on the force sensor at a set position when the tractor implement is the reference implement; k 力值 The corresponding value interval is [k1, k2], wherein when the boundary range values k1 and k2 are exceeded, the corresponding boundary values are taken; when the ratio of the collected force value to the reference force value is not 1, it is judged that the load of the tractor implement changes, and implement load change load compensation is performed according to the ratio of the collected force value to the reference force value.

[0017] Further, a reference speed v1 is set, the reference speed being the average speed of the reference implement in a set descending interval after the control current output to the descending control valve reaches a set current and lasts for a set descending interval; whether the load of the tractor implement changes is judged according to the reference speed.

[0018] Further, the method for judging whether the load of the tractor implement changes according to the reference speed comprises: under the same set current, the average speed of the current tractor implement in the same descending interval is calculated, denoted as current speed v2; setting k 速度 =v2 / v1, k 速度The corresponding value interval is set to [k3, k4]. When the boundary values ​​k3 and k4 are exceeded, the corresponding boundary values ​​are taken; 速度 >1, the load of the machine is greater than that of the reference machine; k 速度 When <1, the load of the machine is smaller than that of the reference machine.

[0019] Furthermore, the load compensation for the load change of the tool is performed based on the ratio of the collected force value to the reference force value, including: setting the upper limit value range of the deceleration buffer zone to [B2%, B1%], where B2% < B% < B1%, B% is the upper limit of the deceleration buffer zone under the control current M output by the controller, and is also k 力值 =1, the corresponding deceleration buffer zone start value; when the descent speed setting knob setting value corresponds to the control current M output by the controller, the upper limit of the buffer zone is k 力值 The interval [k1, k2] and the upper limit range of the deceleration buffer [B2%, B1%] are interpolated to obtain the corresponding value, that is, when k 力值 = k1, the upper limit of the deceleration buffer is set to B2%; when k 力值 =k2, the upper limit of the deceleration buffer is set to B1%; when k1<k 力值 <k2, the upper limit of the deceleration buffer zone corresponds to the interval (B2%, B1%); when the descent speed setting knob is set to different values, the controller outputs different control currents, corresponding to different buffer zones, and thus corresponding to different upper limits of the deceleration buffer zone, set to B3%, and set k at the same time. 电流 =M1 / M, M1 is the current corresponding to other values ​​of the descent speed setting knob, and its value range is [M2, M3]. M3 is the current value corresponding to 100% of the descent speed setting knob, and M2 is the current value corresponding to a certain ratio of the descent speed setting knob. When the descent speed setting knob is set to different values, it corresponds to the upper limit range of the deceleration buffer zone [B4%, B5%], where B4%=B3%-k 电流 * (B%-B2%), B5%=B3%+k 电流 *(B1%-B%), when k 力值 When the value is in the interval [k1, k2] and the current value is in the interval [M2, M3], the upper limit of the deceleration buffer is k. 力值 The interval [k1, k2] and the upper limit range of the deceleration buffer zone [B4%, B5%] are obtained by interpolation.

[0020] Furthermore, the load compensation for the load change of the tool is performed based on the ratio of the collected force value to the reference force value, including: setting the current N1=N+D, wherein N is the first target current of the control current of the descent control valve, N1 is the first deceleration point current, and D is the difference between the current N1 and N. The tool decelerates in the deceleration buffer zone. When the tool reaches the C1% position, the current decreases from the M value to the N1 value, and then the D value is directly reduced to keep the current at the N value. The tool moves from the C1% position to the C% position, wherein C1% is the first deceleration point position, and C% is the lower limit of the deceleration buffer zone; for tools with different loads, the value range of the first deceleration point position is set to [C2%, C3%], wherein C3%<C1%<C2%, and C1% is k at the same time. 力值 =1, the corresponding first deceleration point position; the load compensation process of the machine load change is: the first deceleration point position is k 力值 The interval [k1, k2] and the first deceleration point range [C2%, C3%] are interpolated to correspond to the values, that is, when k 力值 =k1, the first deceleration point in the deceleration buffer zone is set to C2%; when k 力值 =k2, the first deceleration point is set to C3%; when k1<k 力值 When <k2, the first deceleration point is set to the value of the corresponding interval (C2%, C3%).

[0021] In a second aspect, a tractor implement control system is provided, comprising a hydraulic pump, wherein the outlet of the hydraulic pump is respectively connected to the inlet of a differential compensator and the inlet of an ascending control valve; the outlet of the ascending control valve is connected to the rodless chamber of a suspension cylinder via a one-way valve and to a hydraulic oil tank via a relief valve; the rodless chamber of the suspension cylinder is connected to the hydraulic oil tank via a descending control valve; and the outlet of the differential compensator is connected to the hydraulic oil tank; an angle sensor, a force sensor, a height limit setting knob, a depth position setting knob, a descending button, an ascending button, and a descending speed setting knob are respectively connected to the input end of a controller; the output end of the controller is respectively electrically connected to the control ends of the ascending control valve and the descending control valve; and the controller is used to control the tractor implement according to the tractor implement control method described in the first aspect.

[0022] According to a third aspect, a tractor is provided, wherein the tractor is equipped with a tractor implement control system according to the second aspect.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The present invention converts the descent speed setting value into the control current of the descent control valve according to the set control strategy and outputs it to the descent control valve to achieve stable descent control of the tractor implement. This solves the problem that the descent speed varies due to implements of different weights and the fixed deceleration interval cannot meet the buffering requirements. The buffer zone compensation is performed for implements of different loads to adapt to the stable stopping of implements of different weights and solve the stopping shock problem.

[0025] (2) The present invention addresses the problem that temperature changes cause changes in the resistance of the solenoid valve, which in turn causes a large deviation between the same current request and the actual current. The current deviation is compensated to make it consistent with the requested set current value, thereby achieving speed compensation for the machine and ensuring that the machine deceleration and buffering process is not affected by the temperature change of the solenoid valve;

[0026] (3) The present invention performs temperature and load compensation control based on the control strategy, does not increase the hardware cost, and realizes system cost control. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the principle of a tractor implement control system provided by an embodiment of the present invention (schematic diagram of a single-acting cylinder);

[0028] Figure 2 This is a schematic diagram of a control process of a control mode 1 of a tractor implement control method provided by an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of a control process of a second control mode of a tractor implement control method provided by an embodiment of the present invention;

[0030] Figure 4 Schematic diagram of the temperature compensation control process in an embodiment of the present invention;

[0031] Figure 5 2. It is a schematic diagram of the load variation compensation control process between buffer zones according to an embodiment of the present invention;

[0032] Figure 6 2. This is a schematic diagram of a load change small current holding interval compensation control process according to an embodiment of the present invention;

[0033] In the figure: 1. Hydraulic pump; 2. Differential compensator; 3. Ascent control valve; 4. Descent control valve; 5. Check valve; 6. Overflow valve; 7. Suspension cylinder; 8. Angle sensor; 9. Force sensor; 10. Controller; 11. Height limit setting knob; 12. Depth position setting knob; 13. Descent button; 14. Ascent button; 15. Descent speed setting knob. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0035] Example 1:

[0036] A tractor implement control method includes: receiving a descent speed setting value; converting the descent speed setting value into a control current of a descent control valve according to a set control strategy, and outputting the control current to the descent control valve to achieve stable descent control of the tractor implement.

[0037] like Figure 1 , which is a schematic diagram of the principle of a tractor implement control system provided by this embodiment. A hydraulic pump 1 outputs hydraulic oil to a differential compensator 2 and an up control valve 3, and then enters the rodless chamber of a suspension cylinder 7 and the inlet of a relief valve 6 through a one-way valve 5. At the same time, the rodless chamber of the suspension cylinder 7 is connected to a hydraulic oil tank through a down control valve 4. A force sensor 9 is located at the hinge point between the downlink of the suspension mechanism and the tractor to obtain real-time load information of the implement. An angle sensor 8 is concentric with the lift arm and rotates with the lift arm. A controller 10 obtains real-time position information of the implement through the angle sensor 8, and both are electrically connected to the input end of the controller 10. An up button 14 and a down button 13 serve as mode inputs to trigger the up or down movement of the implement. A height limit setting knob 11 and a depth position setting knob 12 are used to set the upper and lower limit positions of the implement. The output end of the controller 10 is electrically connected to the control ends of the up control valve 3 and the down control valve 4, respectively. The controller 10 performs current output compensation according to the compensation strategy to achieve smooth stop control of the implement.

[0038] When the rising button 14 of the electro-hydraulic suspension system is triggered, the hydraulic pump 1 outputs hydraulic oil through the rising control valve 3 and the one-way valve 5, and then flows to the rodless chamber of the suspension cylinder 7. It stops when the setting value of the height limit setting knob 11 is reached. When the descending button 13 is triggered, the controller 10 controls the descent control valve 4 to operate, and the hydraulic oil in the rodless chamber of the suspension cylinder 7 flows to the hydraulic oil tank through the descent control valve 4, and the suspension mechanism descends. It stops when it descends to the value set by the depth position setting knob 12.

[0039] In the specific deceleration and buffering process, take the lowering process of the machine as an example: Figure 1 and Figure 2As shown, first, the descent speed parameter is set (0-100%) through the descent speed setting knob 15. When the descent button 13 is triggered, the controller 10 outputs the corresponding current, such as current M, according to the current of the descent control valve 4 corresponding to the setting value of the descent speed setting knob 15. At the same time, the controller 10 sets the parameters according to the descent speed setting knob 15 to determine the corresponding deceleration buffer zone, such as the deceleration buffer zone H% (H%=B%-C%). When the machine reaches the B% (upper limit of the deceleration buffer zone) position, the controller 10 controls the current of the descent control valve 4 to start decreasing, and reduces the descent speed of the machine. The controller controls the current output according to the distance from the target position. When the machine reaches the target position C% (lower limit of the deceleration buffer zone), the output current of the controller 10 is reduced to the N value (first target current) and directly returns to zero at this point. The stable stop of the machine is achieved through this deceleration buffering method.

[0040] like Figure 3 As shown, in Figure 2 Based on the scheme, compared with Figure 2 The deceleration buffer mode increases the transition process of current reduction. When the controller 10 controls the current of the descending control valve 4 to drop to the N1 value (T 41 At this point in time, the implement's corresponding position is C1% (the first deceleration point). The controller 10's current output decreases directly from N1 to N. As the implement descends from C1% to C%, the controller 10 outputs current at N and maintains it until the tractor reaches the lower limit of the deceleration buffer, serving as a low-current holding buffer. When the tractor reaches the lower limit of the deceleration buffer, the control current of the descent control valve returns directly to zero from the first target current. This deceleration buffering method ensures a stable stop of the tractor.

[0041] Temperature compensation control:

[0042] The controller 10 controls the corresponding current output to the descending control valve 4 according to the setting value of the descending speed setting knob 15. When the pre-output current of the controller 10 reaches the set current size, the controller collects the control current received by the descending control valve 4 in real time; calculates the difference between the control current received by the descending control valve 4 and the control current pre-output by the controller 10. When the difference exceeds the set threshold, the difference is superimposed on the control current output by the controller as the control current output by the controller at the next moment. The specific compensation method is: based on Figure 2Take the deceleration buffer mode as an example: according to the current preset value corresponding to the descent speed setting knob 15, the controller 10 outputs a current of M, that is, the requested current is M. When the external ambient temperature changes or the temperature of the descent control valve 4 itself changes, the resistance value of the descent control valve 4 changes. When the controller 10 outputs the same PWM duty cycle, an actual current is formed at the solenoid valve end of the descent control valve 4. When the temperature drops, the resistance value of the solenoid valve of the descent control valve 4 decreases, and the actual current increases. When the temperature rises, the resistance value of the solenoid valve of the descent control valve 4 increases, and the actual current decreases.

[0043] The specific compensation method includes: when the pre-output current of the controller 10 reaches the set current size, the controller collects the control current received by the descent control valve 4 in real time; calculates the difference between the control current received by the descent control valve 4 and the control current pre-output by the controller, and when the difference exceeds the set threshold, superimposes the difference on the control current output by the controller as the control current output by the controller at the next moment.

[0044] like Figure 4 As shown, when T2 to T 21 Time period when the current collected remains constant in different collection cycles, or the current value fluctuation range is less than M 波动 Time (M 波动 The reference value is 10-20mA), then the actual collected current is determined to be a stable value, and the requested pre-output current value M is compared with the actual current value E. When the current increases, such as the current value E1, Δ1 is set to E1-M, and the current request value is directly reduced by the deviation value Δ1 at the time point T21. At the point T3 when the deceleration buffer starts, the actual current still starts to decrease from the approximate current value M, and stops when it drops to the current request value N2, wherein N2 is set to N-0.5*Δ1, that is, it stops at point T4, and the controller 10 requests the current N2; when T 21 When the feedback current value decreases at a certain time point, such as the current value E2, Δ2=M-E2 is set. Then, at time point T21, the current request value is directly increased by the deviation value Δ2. Then, at point T3 when deceleration begins, the actual current still starts to decrease from the approximate current value M and stops when it drops to N2. Set N2=N+0.5*Δ2.

[0045] Load compensation control:

[0046] When controlling the descent of implements with different loads, according to the principle, the descent speed of the implement is related to the setting value of the descent speed setting knob 15 (corresponding to different current sizes, and thus corresponding to the valve opening sizes) on the one hand, and to the pressure difference before and after the descent control valve 4 on the other hand, that is, it is directly related to the implement load. For implements with the same load, a stable stop control buffer curve can be adjusted, and temperature compensation can be combined to achieve stable control of the implement load and at different temperatures. However, when the implement load changes, the corresponding deceleration range and corresponding current conditions can no longer meet its stable control requirements, so implement load compensation control is required.

[0047] Method 1 for determining load conditions: A reference implement is set, and when the tractor implement is used as the reference implement, the force applied by the reference implement to the force sensor 9 is defined as the reference force value. Whether the load of the tractor implement has changed is determined based on the reference force value. When the load of the tractor implement has changed, load compensation is performed on the control current output to the descent control valve.

[0048] like Figure 2 As shown, when the tool position is set, for example, when the tool is at position A%, the controller 10 collects the force value G1 applied by the reference tool to the force sensor 9. When using other tools with different loads, the force value G2 applied to the force sensor 9 at the same action position A% is collected. The force value G1 generated by the reference tool at position A% is set as the reference force value, and the ratio of the force value generated by the current tool to the reference force value of the reference tool is calculated: k 力值 =G2 / G1, where k 力值 The corresponding value range is [k1, k2]. If the value exceeds the boundary range (less than k1, greater than k2), the boundary value is taken; the reference range of k1 value is [0.4, 0.6], and the reference range of k2 value is [1.8, 2.5]. When k 力值 When >1, the load of the machine is larger than that of the reference machine, k 力值 The larger the value is, the greater the load of the machine is, and vice versa. The controller 10 calculates k 力值 As a result, corresponding load compensation is performed.

[0049] Method 2 for determining load conditions: Set a reference speed, which is the average speed of the reference implement within the set descending interval after the control current output to the descending control valve 4 reaches the set request current and continues within the set descending interval; determine whether the load of the tractor implement has changed based on the reference speed. The specific method includes: after the control current reaches the set request current value and stabilizes for a certain period of time, collect the position change and time within the set interval, such as Figure 2 As shown, the acquisition position A1% (corresponding to time point T 21 ) to position A2% (corresponding to time point T 22) to calculate the speed; speed v1 = set position interval / corresponding time = (A1%-A2%) / (T 22 -T 21 ), as the reference speed; when the descent speed setting knob 15 is set to the same parameters, when different load tools are applied, the same descent interval, the new speed value of the tool descent process is v2, and the current tool load and the reference tool load speed ratio are calculated: k 速度 =v2 / v1, the corresponding interval value is [k3, k4]. If the value exceeds the boundary range (less than k3, greater than k4), the boundary value is taken; the reference value range of k3 is [0.5, 0.7], and the reference value range of k2 is [1.5, 1.8]. Then k 速度 >1, the load of the machine is greater than that of the reference machine; k 速度 <1, the load of the implement is smaller than that of the reference implement, and the controller 10 calculates k 速度 The value result is used to perform corresponding load compensation control.

[0050] Load compensation method 1:

[0051] Collect the force value of the tractor's current implement on the force sensor; calculate the ratio of the collected force value to the reference force value. When the ratio is not 1, it is determined that the load of the tractor implement has changed, and load compensation is performed based on the ratio of the collected force value to the reference force value. Figure 5 As shown, the specific compensation method is: the load change of the machine is judged by k 力值 For example, the load ratio k of different tools and reference tools 力值 In the interval [k1, k2], when the setting value of the descent speed setting knob 15 corresponds to the current value M (as a reference descent current), the upper limit range of the deceleration buffer zone is set to [B2%, B1%], B2%< B%<B1%, where B% is the upper limit of the deceleration buffer zone under the control current M output by the controller 10, and is also k 力值 =1, the corresponding deceleration buffer zone starts at the value; when k 力值 When the interval is [1, k2], the upper limit of the deceleration buffer is set to the interval value [B, B1]. 力值 When the interval is [k1, 1], the upper limit of the deceleration buffer is set to the value of the interval [B2, B]. When the descent speed setting knob is set to a certain value corresponding to the control current M output by the controller, the upper limit of the deceleration buffer is set to k. 力值 The interval [k1, k2] and the upper limit range of the buffer zone [B2%, B1%] are interpolated to obtain corresponding values, that is, when k 力值 = k1, the upper limit of the deceleration buffer is set to B2%; when k 力值 =k2, the upper limit of the deceleration buffer is set to B1%; when k1<k力值 When <k2, the upper limit of the deceleration buffer zone corresponds to the interval (B2%, B1%);

[0052] Furthermore, different descent speed setting knob 15 setting values ​​correspond to different current values ​​M1, and thus correspond to different deceleration buffer zone setting values. When the descent speed knob setting value is larger or smaller, the corresponding deceleration buffer zone is also larger or smaller, corresponding to different buffer zone upper limit values ​​B3%. When the descent speed setting knob 15 is set to different values, the setting k 电流 =M1 / M, M1 value range [M2, M3], M3 is the current value corresponding to 100% setting of the descent speed setting knob, M2 is the current value corresponding to a certain ratio (such as 50%) of the descent speed setting knob setting. When different descent speed setting knob setting values ​​are set, the corresponding upper limit range of the deceleration buffer zone is [B4%, B5%], where B4%=B3%-k 电流 * (B%-B2%), B5%=B3%+k 电流 *(B1%-B%), when k 力值 When the value is within the interval [k1, k2] and the current range is [M2, M3], the upper limit of the deceleration buffer is k 力值 The interval [k1, k2] and the upper limit range of the deceleration buffer zone [B4%, B5%] are obtained by interpolation.

[0053] Load compensation method 2:

[0054] Based on the ratio of the collected force value to the reference force value, when the ratio is not 1, it is determined that the load of the tractor has changed, and load compensation is performed based on the ratio of the collected force value to the reference force value. The specific compensation method is: based on Figure 3 Take the deceleration buffer mode 2 (adding the first deceleration point and setting the low current holding interval) under normal conditions as an example, and adjust the reference stability curve. When setting different load tools, such as Figure 6 As shown, the load ratio values ​​for different tools relative to the reference tool fall within the interval [k1, k2]. The set current N1 is N1 = N + D, where N is the first target current for the descent control valve, N1 is the descent control valve current corresponding to the first deceleration point, and D is the difference between currents N1 and N. The value of D depends on the proportional valve characteristics, with a reference range of [50, 200]. During buffering, the current decreases from M, corresponding to the tool position, to N1 at C1%, then D is directly reduced to maintain the current at N. The tool moves from C1% to C%, where C1% is the first deceleration point and C% is the lower limit of the deceleration buffer zone, which is used to stabilize the tool process and stop.

[0055] For different load machines, the first deceleration point position is set to [C2%, C3%], where C3%<C1%<C2% and C1% is k 力值 =1, the corresponding first deceleration point position; the load compensation process of the machine load change is: the first deceleration point position is k 力值 The interval [k1, k2] and the first deceleration point range [C2%, C3%] are interpolated to correspond to the values, that is, when k 力值 =k1, the first deceleration point in the deceleration buffer zone is set to C2%; when k 力值 =k2, the first deceleration point is set to C3%; when k1<k 力值 When <k2, the first deceleration point is set to the value of the corresponding interval (C2%, C3%), and this method can achieve a stable compensation effect for the load drop of different machines.

[0056] The corresponding ascending system of this embodiment is a load-sensitive system, and its motion characteristics are independent of the load, so there is no need to perform ascending load compensation.

[0057] The present invention realizes compensation control of tractor implements at different temperatures, keeps the implements' ascent and descent, start and stop smooth and is not affected by temperature; realizes load compensation control under different implement loads on the tractor, solves the problem of secondary drop of heavy-loaded implements and high speed when light-loaded implements stop, causing stopping shock; uses a strategic approach rather than a more expensive independent PID chip solution for the controller, and the load can be indirectly fed back through speed or directly through the configured force sensor, without increasing hardware costs.

[0058] The present invention mainly implements the compensation method by taking into account the current size, the deceleration buffer zone size, the small current (first deceleration point) holding interval size, etc. Temperature compensation and load compensation can be implemented in combination simultaneously, and different load compensation methods can also be combined. For example, load compensation can be implemented by combining deceleration buffer zone compensation and small current holding interval compensation. The small current interval and the deceleration buffer zone can be set larger or smaller. At the same time, the load variation coefficient can be adjusted accordingly according to different machines and implements. The present invention is adjusted under a certain ambient temperature or machine load and debugged according to the commonly used working conditions of the corresponding tractor. For example, a moldboard plow is used as a reference machine, and a stable debugging curve at 30°C is used as a reference stable curve. The reference boundary conditions can all be changed.

[0059] Example 2:

[0060] Based on the tractor implement control method described in the first embodiment, this embodiment provides a tractor implement control system, such as Figure 1As shown, it includes a hydraulic pump 1, the outlet of the hydraulic pump 1 is respectively connected to the inlet of the differential compensator 2 and the inlet of the rising control valve 3, the outlet of the rising control valve 3 is connected to the rodless chamber of the suspension cylinder 7 through a one-way valve 5 and is connected to the hydraulic oil tank through a relief valve 6, the rodless chamber of the suspension cylinder 7 is connected to the hydraulic oil tank through a descending control valve 4, and the outlet of the differential compensator 2 is connected to the hydraulic oil tank; the angle sensor 8, the force sensor 9, the height limit setting knob 11, the depth position setting knob 12, the descending button 13, the ascending button 14, and the descending speed setting knob 15 are respectively connected to the input end of the controller 10; the output end of the controller 10 is respectively electrically connected to the control ends of the rising control valve 3 and the descending control valve 4; the controller 10 is used to control the tractor implement according to the tractor implement control method described in Example 1.

[0061] Example 3:

[0062] Based on the tractor implement control system described in the second embodiment, this embodiment provides a tractor equipped with the tractor implement control system described in the second embodiment.

[0063] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A tractor implement control method, characterized in that: include: Receive the descent speed setting value; According to the set control strategy, the descent speed setting value is converted into the control current of the descent control valve, and output to the descent control valve to achieve stable descent control of the tractor implement; The control strategy set includes: Set the deceleration buffer zone according to the descent speed setting value; When the tractor implement reaches the upper limit of the deceleration buffer zone, the control current of the descent control valve begins to be reduced to reduce the descent speed of the tractor implement; When the tractor implement reaches the lower limit of the deceleration buffer zone, the control current of the descending control valve is reduced to the first target current and directly returns to zero at the first target current; Alternatively, the control strategy may include: Setting a deceleration buffer zone according to a set value of the descent speed, and at the same time, setting a first deceleration point, wherein the first deceleration point is located between an upper limit of the deceleration buffer zone and a lower limit of the deceleration buffer zone; When the tractor implement reaches the upper limit of the deceleration buffer zone, the control current of the descent control valve begins to be reduced to reduce the descent speed of the tractor implement; When the tractor implement reaches the first deceleration point, the control current of the descent control valve is reduced to the first deceleration point current, and then directly reduced from the first deceleration point current to the first target current, and maintained at the first target current until the tractor implement descends to the lower limit of the deceleration buffer zone; When the tractor implement reaches the lower limit of the deceleration buffer zone, the control current of the descent control valve returns directly to zero from the first target current.

2. The tractor implement control method according to claim 1, wherein: The control current output to the descending control valve is a temperature-compensated current; the temperature compensation method includes: The controller controls the output of the corresponding current to the descending control valve according to the descending speed setting value. When the controller pre-output current reaches the set current size, the controller collects the control current received by the descending control valve in real time; The difference between the control current received by the descent control valve and the control current pre-output by the controller is calculated. When the difference exceeds the set threshold, the difference is superimposed on the control current output by the controller as the control current output by the controller at the next moment.

3. The tractor implement control method according to claim 2, wherein: The difference is added to the control current output by the controller, specifically: When the actual current E1 received by the descent control valve is greater than the control current M pre-output by the controller based on the descent speed setting, the difference Δ1 is calculated as E1-M. Before the tractor enters the deceleration buffer zone, the difference Δ1 is subtracted from the control current M pre-output by the controller to obtain the control current output by the controller at the next moment. Simultaneously, the first target current is compensated by subtracting half of the difference Δ1 from the first target current to obtain the new first target current. When the actual current E2 received by the descent control valve is less than the control current M pre-output by the controller based on the descent speed setting value, the difference Δ2 is calculated as M-E2; before the tractor enters the deceleration buffer zone, the difference Δ2 is added to the control current M output by the controller to serve as the control current output by the controller at the next moment; at the same time, the first target current is compensated by adding half of the difference Δ2 to the first target current to serve as the new first target current.

4. The tractor implement control method according to claim 1, wherein: A reference implement is set, and the force applied by the reference implement to the force sensor is defined as a reference force value. A determination is made based on the reference force value as to whether the load of the tractor implement has changed. When the load of the tractor implement has changed, load compensation for the implement load change is performed.

5. The tractor implement control method according to claim 4, wherein: The method for determining whether the load of the tractor implement has changed based on the reference force value includes: Collect the force value G2 of the implement currently used by the tractor acting on the force sensor at the set position; Set k 力值 =G2 / G1, where G1 is the force applied by the reference implement to the force sensor at the set position when the tractor implement is the reference implement; k 力值 The corresponding value interval is [k1, k2]. When the boundary values ​​k1 and k2 are exceeded, the corresponding boundary values ​​are taken. The ratio of the collected force value to the reference force value is calculated. When the ratio is not 1, it is determined that the load of the tractor implement has changed. The load compensation of the implement load change is performed according to the ratio of the collected force value to the reference force value.

6. The tractor implement control method according to claim 1, wherein: A reference speed v1 is set. The reference speed is the average speed of the reference implement within the set descent interval after the control current output to the descent control valve reaches the set current and continues within the set descent interval. Whether the load of the tractor implement has changed is determined based on the reference speed.

7. The tractor implement control method according to claim 6, wherein: The method for determining whether the load of the tractor implement changes based on the reference speed includes: Under the same set current, calculate the average speed of the current tractor implement in the same descending interval and record it as the current speed v2; Set k 速度 =v2 / v1,k 速度 The corresponding value interval is set to [k3, k4]. When the boundary values ​​k3 and k4 are exceeded, the corresponding boundary values ​​are taken; 速度 >1, the load of the machine is greater than that of the reference machine; k 速度 When <1, the load of the machine is smaller than that of the reference machine.

8. The tractor implement control method according to claim 1 or 5, wherein: The load compensation for the tool load change based on the ratio of the collected force value to the reference force value includes: Set the upper limit of the deceleration buffer zone to [B2%, B1%], where B2%<B%<B1%, and B% is the upper limit of the deceleration buffer zone under the control current M output by the controller, and is also k 力值 =1, the corresponding deceleration buffer zone start value; When the setting value of the descending speed setting knob corresponds to the control current M output by the controller, the upper limit of the buffer zone is k. 力值 The interval [k1, k2] and the upper limit range of the deceleration buffer [B2%, B1%] are interpolated to obtain the corresponding value, that is, when k 力值 = k1, the upper limit of the deceleration buffer is set to B2%; when k 力值 =k2, the upper limit of the deceleration buffer is set to B1%; when k1<k 力值 When <k2, the upper limit of the deceleration buffer zone corresponds to the interval (B2%, B1%); When the descent speed setting knob is set to different values, the controller outputs different control currents, corresponding to different buffer zones, and thus corresponding to different deceleration buffer zone upper limits, set to B3%, and set k 电流 =M1 / M, M1 is the current corresponding to other values ​​of the descent speed setting knob, and its value range is [M2, M3]. M3 is the current value corresponding to 100% of the descent speed setting knob, and M2 is the current value corresponding to a certain ratio of the descent speed setting knob. When the descent speed setting knob is set to different values, it corresponds to the upper limit range of the deceleration buffer zone [B4%, B5%], where B4%=B3%-k 电流 * (B%-B2%), B5%=B3%+k 电流 *(B1%-B%), when k 力值 When the value is in the interval [k1, k2] and the current value is in the interval [M2, M3], the upper limit of the deceleration buffer is k. 力值 The interval [k1, k2] and the upper limit range of the deceleration buffer zone [B4%, B5%] are obtained by interpolation.

9. The tractor implement control method according to claim 1 or 5, wherein: The load compensation for the tool load change based on the ratio of the collected force value to the reference force value includes: Set the current N1=N+D, where N is the first target current of the control current of the descending control valve, N1 is the current at the first deceleration point, and D is the difference between the currents N1 and N. The machine decelerates within the deceleration buffer zone. When the machine reaches the C1% position, the current decreases from the M value to the N1 value, and then the D value is directly reduced to keep the current at the N value. The machine moves from the C1% position to the C% position, where C1% is the first deceleration point and C% is the lower limit of the deceleration buffer zone. For different load machines, the first deceleration point position is set to [C2%, C3%], where C3%<C1%<C2% and C1% is k 力值 =1, the corresponding first deceleration point position; The load compensation process of the machine load change is as follows: the first deceleration point position is k 力值 The interval [k1, k2] and the first deceleration point range [C2%, C3%] are interpolated to correspond to the values, that is, when k 力值 =k1, the first deceleration point in the deceleration buffer zone is set to C2%; when k 力值 =k2, the first deceleration point is set to C3%; when k1<k 力值 When <k2, the first deceleration point is set to the value of the corresponding interval (C2%, C3%).

10. A tractor implement control system, characterized in that: The invention comprises a hydraulic pump (1), wherein the outlet of the hydraulic pump (1) is connected to the inlet of the differential compensator (2) and the inlet of the rising control valve (3), respectively; the outlet of the rising control valve (3) is connected to the rodless chamber of the suspension cylinder (7) through a one-way valve (5) and is connected to the hydraulic oil tank through a relief valve (6); the rodless chamber of the suspension cylinder (7) is connected to the hydraulic oil tank through a descending control valve (4); and the outlet of the differential compensator (2) is connected to the hydraulic oil tank; The angle sensor (8), the force sensor (9), the height limit setting knob (11), the depth position setting knob (12), the descending button (13), the ascending button (14), and the descending speed setting knob (15) are respectively connected to the input end of the controller (10); The output end of the controller (10) is electrically connected to the control ends of the ascending control valve (3) and the descending control valve (4) respectively; The controller (10) is used for controlling the tractor implement according to the tractor implement control method according to claim 1.

11. A tractor, characterized in that: The tractor is equipped with a tractor implement control system according to claim 10.

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