An open-rotation flexible control method and system for a construction machine

Abstract

The application discloses an open-rotation flexible control method and system for engineering machinery, which realizes different judgments on the rotation state by setting a pilot valve current-operation time curve, and formulates different curves suitable for valve current changes according to different rotation states, controls the rotation in the running processes of starting, accelerating, stable running, decelerating, stopping and the like and the different operations of the operation hand on the rotation, such as micro-adjustment, acceleration stopping, high-speed stopping, micro-adjustment reverse, acceleration stopping reverse and high-speed stopping reverse, guarantees the flexibility of the rotation control, avoids the occurrence of the phenomena of jamming, vibration and air suction, makes the rotation action stable and flexible, and makes the driver feel comfortable.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery technology, specifically to a method and system for flexible control of open-type slewing in engineering machinery. Background Technology

[0002] In construction machinery, the need for slewing mechanisms is ubiquitous. Closed-loop slewing (where the pump and slewing motor are directly connected) causes the slewing mechanism to automatically deflect due to gravity when the machinery tilts, with hydraulic oil flowing only between the pump and motor, leading to heat dissipation and filtration issues. While open-loop systems avoid these problems, the presence of hydraulic valves can cause cavitation in the slewing motor during valve spool closure due to excessively fast closing speed, resulting in sudden braking of the slewing mechanism and impacting the lifespan of the slewing system. Slow valve closure can cause excessively large slewing braking angles. Furthermore, abrupt changes in valve opening during spool movement can cause jamming and vibration during slewing, affecting the operator's experience. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides a flexible control method and system for open-type slewing of engineering machinery. By flexibly controlling the slewing process, it avoids adverse factors such as jamming, vibration, impact, and excessive braking angle during operation, enabling smooth slewing operation and avoiding adverse effects such as impact caused by sudden braking due to excessive weight of the machinery itself.

[0004] The technical solution adopted in this invention is: a flexible control method for open-type slewing of engineering machinery, which includes setting a pilot valve current-running time curve, a flexible control method for slewing acceleration, a flexible control method for slewing deceleration, and a flexible control method for reverse turning.

[0005] The method for setting the pilot valve current-running time curve is as follows: Establish a coordinate system with pilot valve current as the ordinate, running time as the abscissa, and point A as the origin; then set control curves for different control methods.

[0006] The curve of the slewing acceleration flexible control method consists of four segments. The first segment is a straight line from point A to point C with a slope of K1. The ordinate of point C is greater than the minimum opening current of the pilot valve core. The second segment is a straight line from point C to point D with a slope of K2. K2 is greater than K1. The third segment is a straight line from point D to point I with a slope of K3. K3 is less than K2. The ordinate of point I is the pilot valve current corresponding to smooth slewing operation.

[0007] The curve of the slewing deceleration flexible control method consists of three segments: the first segment is the vertical drop from point I to point E, the second segment is the curve from point E to point F, and the third segment is the straight line from point F to the minimum opening current of the pilot valve core.

[0008] The curves for the flexible control of reverse vehicle movement are divided into forward current curves and reverse current curves. The forward current curve is a vertical drop from point I to point E and then cut off. The reverse current curve has three segments. The first segment is a straight line from point A to point B with a slope of K3, where K3 is less than K1. The second segment is a straight line from point B to point D with a slope of K2. The third segment is a straight line from point D to point I with a slope of K3.

[0009] The aforementioned slewing acceleration flexible control method is as follows: the slewing acceleration flexible control curve shows that the pilot valve current increases gradually, and after the pilot valve current exceeds a certain value of the minimum opening current of the valve core, the pilot valve current increases rapidly until it approaches the slewing smooth operation current, at which point the current increases gradually.

[0010] The aforementioned slewing deceleration flexible control method is as follows: the pilot valve current jumps to the first drop point E, then gradually decreases from the first drop point E to the second drop point F, and then decreases from the second drop point F to the minimum opening current of the pilot valve core;

[0011] The aforementioned flexible control method for reverse rotation is as follows: the forward current jumps to the first drop point and then is cut off; the reverse current slowly increases from 0; after a period of time, the reverse current increases rapidly until it approaches the current for stable rotation, at which point the current increases gradually. Here, the forward current refers to the drive current in the same direction as the original rotation, and the reverse current refers to the drive current in the opposite direction to the original rotation after reverse rotation.

[0012] Preferably, the method further includes acquiring the handle signal and the pilot valve current signal, and determining the current rotation stage based on the handle signal and the pilot valve current signal.

[0013] Preferably, the handle signal and the pilot valve current signal are transmitted via a CAN bus.

[0014] Preferably, the handle signal and the pilot valve current signal are linearly matched, and the current value output by the handle signal at the corresponding position is a fixed value.

[0015] Preferably, it also includes a pump flow control valve, wherein the current of the pump flow control valve is matched with the handle stroke, and the conversion formula from handle signal to pump flow valve current is:

[0016] Rf = VC * 1.5 + 136

[0017] PC=RF*(MAX_C-MIN_C) / 1000+MIIIN_C

[0018] Where VC represents the handle output value, Rf represents the proportional value of converting the handle signal into current, the proportional value range is between the upper and lower limits of the electric control handle, PC represents the current output of the pump flow valve, and MAX_C and MIN_C represent the maximum and minimum current of the pump flow valve, respectively.

[0019] Preferably, it also includes a parking flexible control method where the pilot valve current reaches the second drop point F but not the first drop point E. Specifically, the pilot valve current gradually decreases to the vertical coordinate current value corresponding to the second drop point F, and then decreases to the minimum valve core opening current.

[0020] Preferably, it also includes a flexible control method for stopping when the pilot valve current does not reach the second drop point F, specifically, the current drops from the stop point to the minimum valve core opening current.

[0021] A flexible open-loop control system for engineering machinery includes a computer control module. The computer control module can acquire handle signals and pilot valve current signals, and implements the aforementioned flexible open-loop control method for engineering machinery.

[0022] The beneficial effects of this invention are as follows: This invention enables smooth operation of large-tonnage machinery during startup, acceleration, and maximum speed operation. Furthermore, during stopping, whether it's a sudden stop during acceleration or stopping after reaching maximum speed, the adverse effects of excessive inertia such as vibration and shaking are minimized under this algorithm. Other rotational actions, such as secondary starts, reversing during movement, and reversing during maximum speed operation, will also be smoothly executed within the logic strategy of this invention. This invention ensures smooth rotational operation, avoids stress damage to structural components caused by sudden stops, thereby guaranteeing work efficiency and avoiding structural component replacement and downtime costs. Attached Figure Description

[0023] Figure 1 This is the electrical schematic diagram of the present invention;

[0024] Figure 2 This is a hydraulic schematic diagram of the rotary mechanism of the present invention;

[0025] Figure 3 This is the control flowchart of the present invention;

[0026] Figure 4 This is a schematic diagram of slewing flexibility control;

[0027] Figure 5 This is the pilot valve current-run time curve set in this embodiment. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be described in more detail below with reference to the accompanying drawings. The described embodiments are some, but not all, of the embodiments of this invention. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this invention, and should not be construed as limiting the invention. The embodiments of this invention will be described in detail below with reference to the accompanying drawings.

[0029] like Figure 1 As shown, the present invention provides an open-type slewing flexible control system for engineering machinery, including a computer control module. The computer control module can acquire handle signals and pilot valve current signals through a CAN bus.

[0030] like Figure 2 As shown, in this embodiment, both oil pumps supply hydraulic oil for the rotary motion simultaneously. When the handle returns to the neutral position, the closing of the main valve is delayed by the flexible control module to prevent the occurrence of shock, cavitation and other phenomena caused by sudden shutdown.

[0031] like Figure 3 As shown, this invention provides a flexible control method for open-type slewing of engineering machinery. Figure 5 This is the pilot valve current-run time curve set in this embodiment. The specific workflow of each control method is described below:

[0032] The slewing acceleration flexible control method is as follows: The slewing state of the construction machinery is determined based on the handle signal and the pilot valve electrical signal. In the acceleration state, the acceleration current curve is selected. Figure 5 The ACDI curve is shown in the middle. The curve changes with the increase in the handle signal. The slope of the initial segment (AC segment) is relatively gentle, designed for a slow start-up, facilitating micro-operation and attitude adjustment via handle micro-movements. The middle segment (CD segment) has a steeper slope, allowing for rapid acceleration of the mechanical rotation speed and quickly reaching a stable operating state. As the handle approaches its limit (stable operating current), the slope slows down again (DI segment), ensuring a smooth transition from acceleration to constant speed. If the mechanical rotation is not complete on the first attempt and a second start-up is initiated, the starting point on the ACDI curve is determined based on the handle signal and pilot valve signal, allowing for flexible control operation directly from the corresponding position.

[0033] The slewing deceleration flexible control method is as follows: The handle signal is detected; if the handle returns to the neutral position, slewing deceleration flexible control begins. Figure 5The diagram shows the IEF curve. The pilot current jumps to the first descent point (point E), at which point the rotational speed is at its maximum. However, due to this jump, the rotational speed decreases slightly. Afterward, the pilot current gradually decreases from the first descent point to the second descent point (point F) along a gradual descent curve with a relatively gentle slope. This is to allow the pilot current to decrease further. Simultaneously, because the rotational mechanism has significant inertia, a too-rapid descent could cause jamming, subjecting the mechanism to excessive braking force and affecting its lifespan. Therefore, the slow descent in the EF segment achieves flexible deceleration of the rotational mechanism. After the pilot current decreases to the second descent point (point F), the pilot valve current is gradually reduced to the minimum opening current value. This minimum current value is maintained for a period to prevent cavitation and jitter, ensuring a smooth stop. Once rotation stops, the pilot current drops to zero.

[0034] If the system stops when the pilot valve current reaches the second drop point but not the first drop point, then the point within segment EF is determined based on the horizontal coordinate corresponding to the actual pilot current value. Flexible control then begins from that point. Figure 5 ACDG curve

[0035] If the system stops before the pilot valve current reaches the value at the second drop point, the point on the horizontal axis corresponding to the actual pilot current value is determined to be within the range from point F to the minimum current for valve core opening. Flexible control then begins from that point. Figure 5 ACH curve in the middle.

[0036] The reverse-engine flexible control method is divided into reverse-engine operation during the steady-state phase and reverse-engine operation during acceleration. During the steady-state phase, the forward current jumps to the first drop point and then cuts off. The reverse current increases slowly from 0, then increases rapidly after a period of time until it approaches the current for stable rotation, at which point the current increases gradually. The reverse current then increases as follows: Figure 5 The ABDI curve is shown in the diagram. The AB segment represents the waiting time, primarily to allow the slewing mechanism to naturally decelerate after the forward current decreases. During this period, a large reverse current should not be applied. When reversing during acceleration, the reverse current is controlled using the same method as during the steady-state reversing phase. The forward current is cut off after the EF segment decreases to the second decreasing point.

[0037] Figure 4 This is a schematic diagram of slewing control given in this embodiment. In the diagram, the acceleration angle refers to the range of acceleration, the smooth operation angle refers to the range of smooth operation, the slewing stop angle refers to the range of deceleration, and the reverse stop angle refers to the range of operation when reversing.

[0038] This invention provides a logical algorithm for the open-loop flexible control of engineering machinery. As for the slopes K1, K2, K3 and the current values ​​corresponding to the inflection points of each curve in the algorithm, those skilled in the art can set specific values ​​according to different engineering machinery.

[0039] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A flexible control method for open-type slewing of engineering machinery, characterized in that: This method includes setting a pilot valve current-run time curve, a slewing acceleration flexible control method, a slewing deceleration flexible control method, and a reverse-engine flexible control method. The method for setting the pilot valve current-running time curve is as follows: Establish a coordinate system with pilot valve current as the ordinate, running time as the abscissa, and point A as the origin; then set control curves for different control methods. The curve of the slewing acceleration flexible control method consists of four segments. The first segment is a straight line from point A to point C with a slope of K1. The ordinate of point C is greater than the minimum opening current of the pilot valve core. The second segment is a straight line from point C to point D with a slope of K2. K2 is greater than K1. The third segment is a straight line from point D to point I with a slope of K3. K3 is less than K2. The ordinate of point I is the pilot valve current corresponding to smooth slewing operation. The curve of the slewing deceleration flexible control method consists of three segments: the first segment is the vertical drop from point I to point E, the second segment is the curve from point E to point F, and the third segment is the straight line from point F to the minimum opening current of the pilot valve core. The curves for the flexible control of reverse vehicle movement are divided into forward current curves and reverse current curves. The forward current curve is a vertical drop from point I to point E and then cut off. The reverse current curve has three segments. The first segment is a straight line from point A to point B with a slope of K3, where K3 is less than K1. The second segment is a straight line from point B to point D with a slope of K2. The third segment is a straight line from point D to point I with a slope of K3. The aforementioned slewing acceleration flexible control method is as follows: the slewing acceleration flexible control curve shows that the pilot valve current increases gradually, and after the pilot valve current exceeds a certain value of the minimum opening current of the valve core, the pilot valve current increases rapidly until it approaches the slewing smooth operation current, at which point the current increases gradually. The aforementioned slewing deceleration flexible control method is as follows: the pilot valve current jumps to the first drop point E, then gradually decreases from the first drop point E to the second drop point F, and then decreases from the second drop point F to the minimum opening current of the pilot valve core; The aforementioned flexible control method for reverse rotation is as follows: the forward current jumps to the first drop point and then is cut off; the reverse current slowly increases from 0; after a period of time, the reverse current increases rapidly until it approaches the current for smooth rotation operation, at which point the current increases gradually.

2. The method for flexible control of open-type slewing in engineering machinery according to claim 1, characterized in that: The method also includes acquiring handle signals and pilot valve current signals, and determining the current rotation stage based on the handle signals and pilot valve current signals.

3. The method for flexible control of open-type slewing in engineering machinery according to claim 2, characterized in that: The handle signal and pilot valve current signal are transmitted via CAN bus.

4. The method for flexible control of open-type slewing in engineering machinery according to claim 2, characterized in that: The handle signal and the pilot valve current signal are linearly matched, and the current value output by the handle signal at the corresponding position is a fixed value.

5. A flexible control method for open-type slewing of engineering machinery according to claim 1 or 2, characterized in that: It also includes a pump flow control valve, the current of which is matched to the handle stroke, and the conversion formula from handle signal to pump flow control valve current is: Rf = VC * 1.5 + 136 PC=Rf*(MAX_C-MIN_C) / 1000+MIN_C Where VC represents the handle output value, Rf represents the conversion of the handle signal into a current proportional value, the proportional value range is between the upper and lower limits of the electric control handle, PC represents the current output of the pump flow control valve, and MAX_C and MIN_C represent the maximum and minimum current of the pump flow control valve, respectively.

6. The method for flexible control of open-type slewing in engineering machinery according to claim 1, characterized in that: It also includes a flexible control method for stopping when the pilot valve current reaches the second drop point F but not the first drop point E. Specifically, the pilot valve current gradually decreases to the vertical axis current value corresponding to the second drop point F, and then decreases to the minimum valve core opening current.

7. The method for flexible control of open-type slewing in engineering machinery according to claim 1, characterized in that: It also includes a flexible control method for stopping when the pilot valve current does not reach the second drop point F, specifically, the current drops from the stop point to the minimum valve core opening current.

8. A flexible open-loop control system for engineering machinery, characterized in that: The system includes a computer control module, which acquires handle signals and pilot valve current signals, and implements the open-loop flexible control method for engineering machinery as described in any one of claims 1-6.

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