Excavator and control method thereof

Abstract

The invention provides an excavator and a control method thereof, the excavator comprises a control module, a current pump, a hydraulic system and a big arm, the control module outputs control current and sends the control current to the current pump and obtains feedback current from the current pump, the current pump drives the hydraulic system to drive the big arm to move, and the control module outputs the control current according to the following formula I, in is the control current output by the control module next time, Imax is the maximum working current of the current pump, Ic is the feedback current obtained by the control module from the current pump at present, alpha max is the maximum buffer coefficient, alpha n is the current buffer coefficient, and N is the number of times of acceleration. According to the excavator and the control method thereof, the large arm can be uniformly accelerated in the side-sway process, the excavator body is relatively stable, and the safety is relatively high.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering equipment, and particularly relates to an excavator and a control method thereof. Background Art

[0002] During the operation of an excavator, sometimes it is necessary to swing the boom laterally, that is, to swing the boom of the excavator to the left or to the right, parallel or at a certain angle to the side of the vehicle body. In this way, the excavator can operate more flexibly in a limited space, which can help the operator easily solve the problems existing under narrow working conditions. At the same time, it can also enable the operator to reduce the number of operations, improve the operation efficiency, and avoid secondary excavation operations caused by the inability of the vehicle body to reach.

[0003] During the process of the boom swinging, if the acceleration is not uniform, it is easy to cause obvious oscillation of the vehicle body and affect safety. Summary of the Invention

[0004] The purpose of the present invention is to provide an excavator and a control method thereof, in which the boom can be uniformly accelerated during the lateral swing process, the vehicle body is relatively stable, and the safety is relatively high.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides an excavator, which includes a control module, a current pump, a hydraulic system and a boom. The control module outputs a control current to the current pump and obtains a feedback current from the current pump. The current pump drives the hydraulic system to drive the boom to move. The control module outputs the control current according to the following formula (1) to make the boom uniformly accelerate.

[0007] Formula (1):

[0008] where, I n is the control current output by the control module next time, I 0 is equal to I min , which is the idle current of the current pump, I max is the maximum working current of the current pump, I c is the feedback current currently obtained by the control module from the current pump, α max is the maximum buffer coefficient, which is pre-configured as any positive number, α n is the current buffer coefficient, which is pre-tuned and stored in the control module, and its value ranges from 1 to α max and N is the number of accelerations, which is pre-configured as any positive integer.

[0009] In one embodiment, the first formula is pre-tuned to fit a current-time curve, which is formed by tuning a current-flow relationship curve and a flow-time curve. The current-flow relationship curve is the actual working characteristic of the current pump, and the flow-time curve is the desired working curve of the hydraulic system, which is a uniform inclined straight line.

[0010] In one embodiment, the time interval between two adjacent accelerations is Tmin, and the time duration for the control module to complete all accelerations is T, where T = Tmin * N, and the values of T and Tmin can be set according to different actual situations.

[0011] In one embodiment, I N equals I max .

[0012] In one embodiment, the control module outputs a control current according to the following second formula to uniformly accelerate the boom.

[0013] Second formula:

[0014] Among them, for the parameters that are the same in the second formula and the first formula, their meanings are the same. α m is the current buffer coefficient, which is pre-tuned and stored in the control module, and its value ranges from 1 to α max M is the number of α m , and the switching of α m is performed when I c meets a preset condition.

[0015] The present invention also provides a control method for an excavator. The excavator includes a control module, a current pump, a hydraulic system, and a boom. The control method includes: the control module outputs a control current and sends it to the current pump, and obtains a feedback current from the current pump. The current pump drives the hydraulic system to drive the boom to move. The control module outputs a control current according to the following first formula to uniformly accelerate the boom.

[0016] First formula:

[0017] Among them, the I n is the control current to be output by the control module next time, I 0 equals I min , I min is the idle current of the current pump, I max is the maximum working current of the current pump, I c is the feedback current currently obtained by the control module from the current pump, and α maxis the maximum buffer coefficient, which is pre-configured as any positive number, α n is the current buffer coefficient, which is pre-tuned and stored in the control module, and its value ranges from 1 to α max Between them, N is the number of accelerations, which is pre-configured as any positive integer.

[0018] In one embodiment, the formula one is pre-tuned to fit a current-time curve, which is formed by tuning a current-flow relationship curve and a flow-time curve. The current-flow relationship curve is the actual working characteristic of the current pump, and the flow-time curve is the desired working curve of the hydraulic system, which is a uniform oblique straight line.

[0019] In one embodiment, the time interval between two adjacent accelerations is Tmin, and the duration for the control module to complete all accelerations is T, T = Tmin * N, and the values of T and Tmin can be set according to different actual situations.

[0020] In one embodiment, I N is equal to I max .

[0021] In one embodiment, the control module outputs a control current according to the following formula two to make the boom accelerate uniformly.

[0022] Formula two:

[0023] Among them, the parameters in formula two that are the same as those in formula one have the same meaning, α m is the current buffer coefficient, which is pre-tuned and stored in the control module, and its value ranges from 1 to α max Between them, M is the number of α m , and the switching of α m is performed when I c meets the preset conditions.

[0024] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0025] In the excavator and its control method of the present invention, when the boom moves, the control module outputs a control current to the current pump according to formula one, and the current pump drives the hydraulic system to drive the boom to move, so that the boom can accelerate uniformly during the side swing process, the vehicle body is relatively stable, and the safety is relatively high. Brief Description of the Drawings

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those skilled in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0027] Figure 1 Schematic diagram of the current-flow relationship of the current pump of an excavator provided by the first embodiment of the present invention;

[0028] Figure 2 Schematic diagram of the desired flow-time relationship of the hydraulic system of an excavator provided by the first embodiment of the present invention;

[0029] Figure 3 Schematic diagram of the current-time relationship of the current pump of an excavator provided by the first embodiment of the present invention. Specific Embodiments

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention. It should be noted that the description order of the following embodiments does not limit the preferred order of the embodiments of the present invention. And in the following embodiments, each embodiment is described with emphasis. For parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0031] The first embodiment of the present invention provides an excavator, which includes a control module, a current pump, a hydraulic system, and a boom. The control module outputs a control current to the current pump and obtains a feedback current from the current pump. The current pump drives the hydraulic system to drive the boom to move. The control module outputs a control current according to the following formula (1) to make the boom accelerate uniformly.

[0032] Formula (1):

[0033] where I n is the control current output by the control module next time, I 0 is equal to I min , I min is the idle current of the current pump, I max is the maximum working current of the current pump, I c is the feedback current currently obtained by the control module from the current pump, and α man is the maximum buffer coefficient, which is pre-configured as any positive number, αn is the current buffer coefficient, which is pre-set and stored in the control module, and has a value of 1 to α max Where N is the number of accelerations and is pre-configured as an arbitrary positive integer.

[0034] In the excavator of the present invention, when the boom is moving, the control module outputs a control current to the current pump according to formula 1, and the current pump drives the hydraulic system to drive the boom to move, so that the boom can be accelerated evenly during the side swing process, the body is relatively stable, and the safety is relatively high.

[0035] In more depth, the reason why the control module can accelerate the arm evenly by outputting the control current according to Formula 1 is that, in one embodiment, Formula 1 is pre-adjusted and fit with a current-time curve, and the current-time curve is formed by adjusting a current-flow relationship curve and a flow-time curve. The current-flow relationship curve is the actual working characteristic of the current pump, and the flow-time curve is the expected working curve of the hydraulic system, which is a uniform inclined straight line.

[0036] To better understand the above "tuning" and "fitting", please refer to the following Figures 1-3 A specific embodiment is shown for description. Figure 1 The figure shows the actual working characteristic curve of the current-flow relationship of a current pump, where the current I is the input of the current pump and the flow P is the output of the current pump. It is easy to see that the current I and the flow P are not in a linear relationship (note that the flow P has a maximum value. When the current I reaches a certain level, the flow P will remain unchanged). The current-flow relationship curve can be obtained from the technical data of the current pump, and the minimum and maximum values ​​of the current I in the figure are the idle current I of the current pump mentioned above. min and the maximum operating current of the current pump I max , which can also be obtained from the technical data of the current pump.

[0037] Figure 2 The flow-time working curve expected by a hydraulic system is a uniform straight line. The so-called "expected" means that if the relationship between the flow P received by the hydraulic system and the time T is Figure 2 If the curve (oblique straight line) shown in the figure changes, the hydraulic system can drive the boom to accelerate evenly.

[0038] Then, Figure 1 The current-flow relationship curve and Figure 2 The flow-time curve shown is adjusted, and we get Figure 3 The current-time curve shown is because as mentioned above Figure 2 The flow-time curve shown means that the hydraulic system can drive the boom to accelerate uniformly.Figure 3 The shown current-time curve also means that if the relationship between the magnitude of the control current I of the current pump and time T changes according to the Figure 3 shown curve, then the current pump can drive the hydraulic system to drive the boom to accelerate evenly.

[0039] Next, tune Formula 1 so that the curve it shows fits with the Figure 3 shown current-time curve. After Formula 1 is tuned and fitted, because as described above Figure 3 the shown curve means that the current pump can drive the hydraulic system to drive the boom to accelerate evenly, so it means that if the control module outputs the control current according to Formula 1, the current pump can drive the hydraulic system to drive the boom to accelerate evenly.

[0040] The tuning and fitting of Formula 1 mainly involves determining each parameter. As described above, the idle current I of the current pump min and the maximum working current I of the current pump max can both be obtained from the technical data of the current pump. The other most crucial one is the number of accelerations N. In one embodiment, the number of accelerations N follows the following relationship: the time interval between two adjacent accelerations is Tmin, the duration for the control module to complete all accelerations is T, T = Tmin * N, and T and Tmin can be set to different values according to different actual situations. Among them, the duration T for the control module to complete all accelerations is set manually and can be set to different values according to different actual situations. For example, it can be set to 1 second or 2 seconds to complete the acceleration as soon as possible, or it can be set to 5 seconds or even 10 seconds or more to complete the acceleration, and the most stable and fast scheme can be determined according to the actual situation. And the time interval Tmin between two adjacent accelerations, that is, the time interval between two adjacent output control currents of the control module. If the time interval is too long, it is difficult to fit with the Figure 3 shown current-time curve or the fitting difference is large. If the time interval is too short, the performance requirements for the control module and the current pump will be relatively high. Therefore, it is also possible to try multiple times according to different actual situations to determine the most stable and fast scheme. When tuning and determining the number of accelerations N (and the time interval Tmin between two adjacent accelerations, the duration T for the control module to complete all accelerations), the maximum buffer coefficient α max and the current buffer coefficient α n are also tuned and determined simultaneously. Among them, the maximum buffer coefficient α max is set arbitrarily by humans and is generally pre-configured as any positive number. And the current buffer coefficient α n makes the relationship between each I n and the corresponding time (that is, each acceleration, each output control current, and the adjacent time interval is Tmin) fit with the Figure 3The current-time curve shown is fitted. In this way, after the tuning and fitting are completed, finally N αs are obtained. n which are pre-stored in the control module and called for calculation each time the control module outputs a control current. Finally, it should be noted that in Formula 1, the feedback current I c is used instead of the previous control current I n-1 , which can improve the accuracy; because if the previous control current I n-1 is used instead of the real-time feedback current I c , it may cause the control current I n output by the control module each time to be very different from the actual current in the current pump, and thus it is simply impossible to achieve the uniform acceleration of the boom.

[0041] After the tuning is completed according to the above tuning process to make Formula 1 fit well with the current-time curve, when the control module actually outputs the control current, it can calculate the corresponding control current according to Formula 1 at each time interval of Tmin and output it. In actual use, when the operator (user) starts to operate the side swing of the boom, the current pump is in the idle state, so the initial value I n of I 0 is equal to the idle current I min of the current pump. And if calculated according to Formula 1 all the time, I n will never reach I max , so when n is equal to N, I N is forced to be equal to I max , so that the actually output current-time curve coincides with the ideal current-time curve to achieve the uniform acceleration in the ideal as much as possible.

[0042] It is true that according to the above content, it is easy to see that the value of the current buffer coefficient α n will be very numerous, there will be N (the value of N is generally in the hundreds), which will affect the overall performance. The technical personnel further research found that there will be a large number of identical values for the value of α n , and it can be divided into multiple small segments following the change of I c (which is also following the change of time). The value of α n is the same within each small segment, and the value of α n is different for adjacent small segments. Therefore, in one embodiment, the control module outputs the control current according to the following Formula 2 to make the boom accelerate uniformly.

[0043] Formula 2:

[0044] Among them, for the parameters that are the same in Formula 2 and Formula 1, their meanings are the same. α m is the current buffer coefficient, which is pre-tuned and stored in the control module, and its value is from 1 to αmax Between them, M is α m The quantity of α m The switching of α c is performed when I meets a preset condition.

[0045] That is, during the setting process, α is summarized m There are a total of 10. Correspondingly, 10 judgment ranges are set for I c Then, during the calculation process, it is judged whether I c is within the first judgment range. If so, α m takes the value of the first α 1 ; Subsequently, when it is judged that I c is within the second judgment range, α m takes the value of the second α 2 ; And so on. In this way, the overall workload is reduced and the work efficiency is improved.

[0046] According to the above content, correspondingly, the second embodiment of the present invention provides a control method for an excavator. The excavator includes a control module, a current pump, a hydraulic system, and a boom. The control method includes: the control module outputs a control current to the current pump and obtains a feedback current from the current pump. The current pump drives the hydraulic system to drive the boom to move. The control module outputs the control current according to the following formula (1) to make the boom accelerate uniformly,

[0047] Formula (1):

[0048] Wherein, the I n is the control current output by the control module next time. I 0 is equal to I min , which is the idle current of the current pump. I max is the maximum working current of the current pump. I c is the feedback current currently obtained by the control module from the current pump. α max is the maximum buffer coefficient, which is pre-configured as any positive number. α n is the current buffer coefficient, which is pre-set and stored in the control module, and takes a value between 1 and α max Between them, N is the number of accelerations, which is pre-configured as any positive integer.

[0049] In one embodiment, the formula (1) is pre-set and fitted to a current-time curve, which is formed by calibrating a current-flow relationship curve and a flow-time curve. The current-flow relationship curve is the actual working characteristic of the current pump, and the flow-time curve is the desired working curve of the hydraulic system, which is a uniform oblique straight line.

[0050] In an embodiment, the time interval between two adjacent accelerations is Tmin, and the duration for the control module to complete all accelerations is T, where T = Tmin * N. The values of T and Tmin can be set differently according to different actual situations.

[0051] In an embodiment, I N equals I max .

[0052] In an embodiment, the control module outputs a control current according to the following formula two to uniformly accelerate the boom.

[0053] Formula Two:

[0054] Among them, for the parameters in Formula Two that are the same as those in Formula One, their meanings are the same. α m is the current buffer coefficient, which is pre-tuned and stored in the control module, and its value ranges from 1 to α max M is the number of α m , and the switching of α m is performed when I c meets a preset condition.

[0055] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0056] In the excavator and its control method of the present invention, during the movement of the boom, the control module outputs a control current to the current pump according to Formula One, and the current pump drives the hydraulic system to drive the boom to move, so that the boom can be uniformly accelerated during the side swing process, the vehicle body is relatively stable, and the safety is relatively high.

[0057] 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 changes or substitutions, which should all be covered within 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. In addition, specific examples are used in the specification to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention, and the content of this specification should not be construed as a limitation to the present invention.

Claims

1. An excavator, characterized in that: The excavator includes a control module, a current pump, a hydraulic system and a boom. The control module outputs a control current to the current pump and obtains a feedback current from the current pump. The current pump drives the hydraulic system to move the boom. The control module outputs a control current according to the following formula 1 to uniformly accelerate the boom. Formula 1: Among them, I n is the control current output by the control module next time, I0 is equal to I min , is the idle current of the current pump, I max is the maximum operating current of the current pump, I c is the feedback current currently obtained by the control module from the current pump, α max is the maximum buffer coefficient, which is pre-configured as an arbitrary positive number, α n is the current buffer coefficient, which is pre-set and stored in the control module, and has a value of 1 to α max Where N is the number of accelerations and is pre-configured as an arbitrary positive integer.

2. The excavator according to claim 1, characterized in that: The formula is pre-adjusted and fitted with a current-time curve, and the current-time curve is formed by adjusting a current-flow relationship curve and a flow-time curve. The current-flow relationship curve is the actual working characteristic of the current pump, and the flow-time curve is the expected working curve of the hydraulic system, which is a uniform inclined straight line.

3. The excavator according to claim 1, characterized in that: The time interval between two adjacent accelerations is Tmin, and the time length for the control module to complete all accelerations is T, where T=Tmin*N. Different values ​​of T and Tmin can be set according to different actual conditions.

4. The excavator according to claim 1, characterized in that: I N Etc. I max .

5. The excavator according to claim 1, characterized in that: The control module outputs a control current according to the following formula 2 to make the arm accelerate uniformly: Formula 2: Among them, the parameters in Formula 2 that are the same as those in Formula 1 have the same meanings, α m is the current buffer coefficient, which is pre-set and stored in the control module, and has a value of 1 to α max Between, M is α m The number of m The switch is made by I c It is carried out when the preset conditions are met.

6. A control method for an excavator, characterized in that: The excavator includes a control module, a current pump, a hydraulic system and a boom, and the control method includes: the control module outputs a control current to the current pump and obtains a feedback current from the current pump, the current pump drives the hydraulic system to drive the boom to move, and the control module outputs a control current according to the following formula 1 to uniformly accelerate the boom. Formula 1: Among them, the I n is the control current output by the control module next time, I0 is equal to I min , I min is the idle current of the current pump, I max is the maximum operating current of the current pump, I c is the feedback current currently obtained by the control module from the current pump, α max is the maximum buffer coefficient, which is pre-configured as an arbitrary positive number, α n is the current buffer coefficient, which is pre-set and stored in the control module, and has a value of 1 to α max Where N is the number of accelerations and is pre-configured to be any positive integer.

7. The control method of an excavator according to claim 6, characterized in that: The formula is pre-adjusted and fitted with a current-time curve, and the current-time curve is formed by adjusting a current-flow relationship curve and a flow-time curve. The current-flow relationship curve is the actual working characteristic of the current pump, and the flow-time curve is the expected working curve of the hydraulic system, which is a uniform inclined straight line.

8. The control method of an excavator according to claim 6, characterized in that: The time interval between two adjacent accelerations is Tmin, and the time length for the control module to complete all accelerations is T, where T=Tmin*N. Different values ​​of T and Tmin can be set according to different actual conditions.

9. The control method of an excavator according to claim 6, characterized in that: I N Etc. I max .

10. The control method of an excavator according to claim 6, characterized in that: The control module outputs a control current according to the following formula 2 to make the arm accelerate uniformly: Formula 2: Among them, the parameters in Formula 2 that are the same as those in Formula 1 have the same meanings, α m is the current buffer coefficient, which is pre-set and stored in the control module, and has a value of 1 to α max Between, M is α m The number of m The switch is made by I c It is carried out when the preset conditions are met.

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