CN108401598B - Method and device for accurately controlling three-point suspension height of tractor - Google Patents
Method and device for accurately controlling three-point suspension height of tractor Download PDFInfo
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- CN108401598B CN108401598B CN201711201593.8A CN201711201593A CN108401598B CN 108401598 B CN108401598 B CN 108401598B CN 201711201593 A CN201711201593 A CN 201711201593A CN 108401598 B CN108401598 B CN 108401598B
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- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01B—SOIL WORKING IN AGRICULTURE OR FORESTRY; PARTS, DETAILS, OR ACCESSORIES OF AGRICULTURAL MACHINES OR IMPLEMENTS, IN GENERAL
- A01B63/00—Lifting or adjusting devices or arrangements for agricultural machines or implements
- A01B63/02—Lifting or adjusting devices or arrangements for agricultural machines or implements for implements mounted on tractors
- A01B63/10—Lifting or adjusting devices or arrangements for agricultural machines or implements for implements mounted on tractors operated by hydraulic or pneumatic means
- A01B63/1006—Lifting or adjusting devices or arrangements for agricultural machines or implements for implements mounted on tractors operated by hydraulic or pneumatic means the hydraulic or pneumatic means structurally belonging to the tractor
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- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01B—SOIL WORKING IN AGRICULTURE OR FORESTRY; PARTS, DETAILS, OR ACCESSORIES OF AGRICULTURAL MACHINES OR IMPLEMENTS, IN GENERAL
- A01B59/00—Devices specially adapted for connection between animals or tractors and agricultural machines or implements
- A01B59/06—Devices specially adapted for connection between animals or tractors and agricultural machines or implements for machines mounted on tractors
- A01B59/066—Devices specially adapted for connection between animals or tractors and agricultural machines or implements for machines mounted on tractors of the type comprising at least two lower arms and one upper arm generally arranged in a triangle (e.g. three-point hitches)
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- Environmental Sciences (AREA)
- Zoology (AREA)
- Lifting Devices For Agricultural Implements (AREA)
Abstract
The invention relates to a method and a device for accurately controlling the three-point suspension height of a tractor. This agricultural implement height control device includes: a target height value acquisition unit (1) which acquires a target height value of an agricultural implement; the hydraulic oil cylinder telescopic distance determining device (2) determines the telescopic distance of a piston rod of the hydraulic oil cylinder according to the current stroke of the hydraulic oil cylinder and the functional relation between the stroke of the hydraulic oil cylinder and the suspension height; and the electro-hydraulic proportional valve control signal generating unit (3) generates an electro-hydraulic proportional valve control signal according to the distance determined by the hydraulic oil cylinder telescopic distance determining device (2).
Description
Technical Field
The invention belongs to the technical field of agricultural machinery control, and relates to a method and a device for accurately controlling the height of a three-point suspension device of an agricultural tractor.
Background
The agricultural implement is hinged with the tail ends of an upper pull rod and a lower pull rod of a hydraulic suspension mechanism of the tractor through three hitching points on a suspension frame, and the three-point suspension is called three-point suspension. The agricultural implement hung in a three-point suspension mode has small relative swing amount, and the agricultural implement has good stability along with the linear running of the tractor. The three-point suspension is mainly used for hitching various farm implements to complete the work of weeding, spraying pesticide, ploughing, harvesting and the like, and is an important component of a tractor. Different agricultural implements have different functions, and the corresponding suspension heights are different when the agricultural implements are connected with the tractor. Therefore, when the agricultural implement is hung, the height of the three-point suspension mechanism needs to be adjusted.
The three-point suspension mechanism of the tractor mainly depends on the extension and the shortening of the hydraulic oil cylinder to realize the lifting, and a driver can operate the electro-hydraulic proportional valve through a key, a knob or a switch to control the oil cylinder to stretch. In the prior art, most of three-point suspension height adjustment is open-loop control within a range of 0-100% of the stroke of the oil cylinder, namely, a key is pressed down, the suspension mechanism ascends/descends, the key is pressed down again, and the suspension mechanism stops ascending/descending. In the lifting process, the problem that a driver cannot obtain the accurate height value of the suspension device exists. In order to adjust the three-point suspension mechanism to the height required by successfully hooking each agricultural implement, sometimes the suspension device needs to be controlled to lift for 1cm or shorter, therefore, people outside the vehicle need to observe the suspension height and feed back the height information to a driver, the driver controls the suspension device to lift, the target height can be reached repeatedly, the labor intensity of operators is increased, and the working efficiency is reduced.
Disclosure of Invention
The present invention has been made in view of the above problems, and provides at least one advantageous option for overcoming or alleviating one or more of the above problems.
In order to achieve the above object, according to one aspect of the present invention, there is provided an agricultural implement height control device including: a target height value obtaining unit which obtains a target height value of the agricultural implement; the hydraulic oil cylinder telescopic distance determining device determines the telescopic distance of a piston rod of a hydraulic oil cylinder according to the current stroke of the hydraulic oil cylinder and the functional relation between the stroke of the hydraulic oil cylinder and the suspension height; and the electro-hydraulic proportional valve control signal generating unit generates an electro-hydraulic proportional valve control signal according to the distance determined by the hydraulic oil cylinder telescopic distance determining device.
According to another aspect of the present invention, there is provided an agricultural implement height control method, comprising: a target height value acquisition step, which is used for acquiring a target height value of the agricultural implement; determining the telescopic distance of a hydraulic oil cylinder, namely determining the telescopic distance of a piston rod of the hydraulic oil cylinder according to the current stroke of the hydraulic oil cylinder and the functional relation between the stroke of the hydraulic oil cylinder and the suspension height; and generating an electro-hydraulic proportional valve control signal, namely generating the electro-hydraulic proportional valve control signal according to the determined distance.
According to the embodiment of the invention, the working efficiency can be improved.
Drawings
Fig. 1 shows a schematic block diagram of an agricultural implement height control apparatus according to an embodiment of the present invention.
FIG. 2A is a schematic front view illustrating the connection of a hydraulic ram to one embodiment of a three point hitch implement.
FIG. 2B is a side view schematic illustrating the connection of a hydraulic ram to an embodiment of a three point hitch implement.
Fig. 3 shows a schematic plan view of the connection relation diagram shown in fig. 2.
FIG. 4 shows a schematic flow diagram of an agricultural implement height control method according to one embodiment of the present disclosure.
Detailed Description
The following description of the embodiments of the present invention with reference to the drawings is illustrative, and not intended to limit the scope of the invention.
Fig. 1 shows a schematic block diagram of an agricultural implement height control apparatus according to an embodiment of the present invention. As shown in fig. 1, an agricultural implement height control apparatus according to an embodiment of the present invention includes: the device comprises a target height value acquisition unit 1, a hydraulic oil cylinder telescopic distance determination device 2 and an electro-hydraulic proportional valve control signal generation unit 3. For convenience of illustration, the electro-hydraulic proportional valve 4 and hydraulic ram 5 are also shown. In addition, the electro-hydraulic proportional valve 4 may be part of an agricultural implement height control device according to an embodiment of the present invention.
According to a further embodiment, the agricultural machine height control device further comprises a magnetostrictive displacement sensor 6.
The target height value acquisition unit 1 acquires a target height value of the agricultural implement. The target height value obtaining unit 1 may be an information interaction unit in a cab, and a driver may input a target height value through an operation interface provided by the information interaction unit.
The hydraulic cylinder telescopic distance determining device 2 calculates the distance that the piston rod of the hydraulic cylinder needs to be stretched according to the current hydraulic cylinder stroke (namely the extension distance of the piston rod of the hydraulic cylinder) and the functional relation between the hydraulic cylinder stroke and the suspension height.
And the electro-hydraulic proportional valve control signal generating unit 3 is used for generating an electro-hydraulic proportional valve control signal according to the distance determined by the hydraulic oil cylinder telescopic distance determining device 2.
The electro-hydraulic proportional valve 4 controls the hydraulic oil cylinder 5 to act according to the electro-hydraulic proportional valve control signal.
In addition, a magnetostrictive displacement sensor 6 arranged on the hydraulic oil cylinder acquires a displacement signal of a hydraulic oil cylinder piston reflecting the current stroke of the hydraulic oil cylinder and feeds the signal back to the hydraulic oil cylinder telescopic distance determining device 2, the hydraulic oil cylinder telescopic distance determining device 2 judges whether the hydraulic oil cylinder is in place or not, if not, the fed back stroke of the hydraulic oil cylinder piston is used as the current stroke of the hydraulic oil cylinder, and the new distance which needs to be stretched by the hydraulic oil cylinder is calculated according to the target height value of the agricultural implement. And the electro-hydraulic proportional valve control signal generating unit 3 generates an updated electro-hydraulic proportional valve control signal according to the new distance.
The magnetostrictive displacement sensor 6 is an absolute value output, non-contact displacement sensor. The sensor utilizes the magnetostrictive principle to accurately detect the absolute position of the movable magnetic ring by an internal non-contact measurement and control technology to measure the actual displacement of a measured product. The magnetostrictive displacement sensor 6 is an example of the cylinder displacement signal acquisition unit of the present invention. According to one embodiment, the magnetostrictive displacement sensor 6 is fixed in an opening of the end cover of the hydraulic oil cylinder, detects a displacement signal of the hydraulic oil cylinder, and feeds back current stroke information of the hydraulic oil cylinder. According to one embodiment, the hydraulic oil cylinder telescopic distance determining device 2 records the current stroke information of the oil cylinder fed back by the magnetostrictive displacement sensor 6 for later determining the telescopic distance of the hydraulic oil cylinder.
According to one embodiment of the invention, the height control device of the agricultural implement comprises a display unit, and the display unit can display the displacement information of the hydraulic oil cylinder measured by the magnetostrictive displacement sensor in real time, or display the height of the agricultural implement obtained according to the displacement signal, or display both the height of the agricultural implement and the displacement of the piston rod of the hydraulic oil cylinder.
FIG. 2 is a schematic diagram illustrating the connection of a hydraulic ram to one embodiment of a three point hitch implement. Fig. 2A is a front view, and fig. 2B is a side view. As shown in fig. 2, the hydraulic cylinder 5 is connected to the lifting rod 7 and the lower link 8, and the lifting rod 7 and the lower link 8 rotate around the connecting point to change the height of the suspension mechanism under the driving of the hydraulic cylinder 5. The geometric relationship of the three components can be approximately seen as a triangular structure.
One end of the hydraulic oil cylinder 5 is connected with the lower pull rod 8 through the connecting component, the other end of the hydraulic oil cylinder is connected with the lifting rod 7 through the connecting component, and the connecting part is in rotatable connection. When the piston rod of the hydraulic oil cylinder 5 stretches, the lifting rod 7 drives the lower pull rod 8 to rotate by taking the connecting part as a center, namely the geometric relationship among the three components is changed as follows: the included angle between the hydraulic oil cylinder 5 and the lifting rod 7 is reduced, and the included angle between the lifting rod 7 and the lower pull rod 8 is increased. Thereby moving the hook 9 provided at the end of the lower link up and down. The height of the hook 9 is the height required for hooking the agricultural implement.
Fig. 3 shows a schematic plan view of the connection relation diagram shown in fig. 2. As shown in fig. 3, AB denotes a hydraulic cylinder 4, AE denotes a lifting rod 7, BI denotes a lower tie rod 8, which form a triangle Δ ABE, a, B, E are three connection points, I is the position of the hanging hook, the distance of the hanging hook from the ground is the height of the three-point suspension mechanism, denoted by H, and can be in mm. If the length of the side AB where the oil cylinder is located is x, if the initial length of the hydraulic oil cylinder is l, the stroke of the piston rod is Δ l (the initial length of the oil cylinder is the length of the piston rod when the stroke is 0, and the stroke of the piston rod is the current stroke), the length of the side AB where the oil cylinder is located is x ═ l + Δ l, the unit: mm. The lengths of the lifting rod and the lower pull rod are fixed constants (obtained by looking up design parameters of three-point suspension), and AE is k1，BE＝k2EI＝k3。
Extending AB to point C, BC ═ k4And CD means ground. The included angle between the AC and the ground is alpha, and the included angle alpha is unchanged because the position of the oil cylinder is fixed. In Δ ABE, angle BAE ═ θ, which can be obtained by the cosine theorem:
in Δ ACD, AC ═ k4+ x, angle CAD ═ θ, angle ACD ═ α, angle ADC ═ pi- θ - α, and can be obtained by sine theorem:
therefore, it is
Let EF ^ CD, and let h ^ EF. In Δ DEF, h ═ DE · sin ═ ADF,
in Δ ABE, one can derive from the sine theorem:
Because EJ// BG, therefore
In the case of the delta EIJ, the peak value,
the height H + H' of the three-point suspension can be seen in the figure.
Therefore, it is
Will be provided with
By substituting the above formula, the functional relationship between the three-point suspension height and the cylinder stroke H ═ f (x) can be obtained.
Therefore, when the target height of the agricultural implement is input, the Δ H can be known according to the current height of the agricultural implement, and the stroke Δ x of the piston rod of the hydraulic oil cylinder, which needs to be extended and retracted, can be known according to the above formula.
The specific connection relationship is explained above, and the corresponding function can be determined based on other connection modes of the agricultural implement, so that the relationship between the target height of the agricultural implement and the stroke delta x of the piston rod required to be stretched can be calculated.
According to another embodiment of the invention, the invention also discloses an agricultural implement height control method. FIG. 4 shows a schematic flow diagram of an agricultural implement height control method according to one embodiment of the present disclosure. As shown in fig. 4, an agricultural implement height control method according to an embodiment of the present invention includes:
determining the target height of the agricultural implement S100. the driver can set the required target height H according to the actual situation of the required height of the agricultural implement to be hung through the operation interface2；
An oil cylinder stroke determining step S200, namely determining the target height H of the agricultural implement according to2With actual height H of agricultural implements1And calculating the distance of the piston rod of the hydraulic oil cylinder needing to be extended or shortened. The method for calculating the distance can be referred to the above description, and the calculation is carried out according to the function determined by the connection relation between the hydraulic oil cylinder and the agricultural implement;
an electro-hydraulic proportional valve control signal generating step S300, generating an electro-hydraulic proportional valve control signal;
in the lifting control step S400, an electro-hydraulic proportional valve controls the stroke of a hydraulic oil cylinder according to the control signal of the electro-hydraulic proportional valve, so that the agricultural implement is driven to ascend or descend;
a feedback control step S500 of receiving the feedback signal of the magnetostrictive displacement sensor and calculating the adjusted height H2', if a predetermined target height is reached, i.e. H2′＝H2The process ends, otherwise steps S200-S400 are repeated.
In addition, according to an embodiment of the present invention, the method further includes a displaying step of displaying a displacement signal of the hydraulic cylinder measured by the magnetostrictive displacement sensor in real time, or displaying a height of the agricultural implement obtained from the displacement signal, or displaying both the height of the agricultural implement and a displacement of a piston rod of the hydraulic cylinder.
The description of the method may be used to understand the method of the present invention and the description of the apparatus may be used to understand the apparatus of the present invention.
According to the embodiment of the invention, the target height is set through the display screen operation interface, the control unit calculates the telescopic distance of the oil cylinder and judges whether the oil cylinder is adjusted in place, and people inside and outside the tractor do not need to repeatedly observe and adjust, so that the agricultural implement can be hooked more quickly.
According to some embodiments of the invention, the three-point suspension position setting is completed by using the operation interface of the display unit such as a display screen, the spatial layout in the cab is optimized, and the complexity of the driving operation can be greatly reduced.
Claims (5)
1. An agricultural implement height control device comprising:
a target height value acquisition unit (1) which acquires a target height value of an agricultural implement;
the hydraulic oil cylinder telescopic distance determining device (2) determines the telescopic distance of a piston rod of the hydraulic oil cylinder according to the current stroke of the hydraulic oil cylinder and the functional relation between the stroke of the hydraulic oil cylinder and the suspension height;
an electro-hydraulic proportional valve control signal generating unit (3) for generating an electro-hydraulic proportional valve control signal according to the distance determined by the hydraulic oil cylinder telescopic distance determining device (2),
wherein the agricultural implement suspension mechanism comprises a lower pull rod (8), a lifting rod (7) and a hook (9) arranged at the tail end of the extension part of the lower pull rod (8), one end of the hydraulic oil cylinder (5) is rotatably connected with the lower pull rod (8) through a connecting component, the other end of the hydraulic oil cylinder is rotatably connected with the lifting rod (7) through a connecting component, when a piston rod of the hydraulic oil cylinder (5) extends and retracts, the lifting rod (7) drives the lower pull rod (8) to rotate by taking the connecting part of the lower pull rod and the connecting component as a center,
wherein the lower pull rod (8), the lifting rod (7) and the hydraulic oil cylinder (5) are regarded as triangles, the functional relation between the stroke of the hydraulic oil cylinder and the suspension height is determined according to the geometric relation between the hydraulic oil cylinder and the agricultural implement suspension mechanism,
the function relation between the stroke of the hydraulic oil cylinder and the suspension height is as follows:
wherein
The initial length of hydraulic cylinder is l, and the piston rod stroke is delta l, the length AE of lifting rod is k1The length BE of the pull-down rod is k2The length EI ═ k of the extension part of the lower pull rod3Setting the end point of the hydraulic oil cylinder close to the ground as B, extending the hydraulic oil cylinder to the intersection point with the ground along the length direction as C, wherein BC is equal to k4The included angle between the hydraulic oil cylinder and the ground is alpha.
2. The agricultural implement height control device according to claim 1, characterized in that the agricultural implement height control device further comprises a cylinder displacement signal acquisition unit (6), the cylinder displacement signal acquisition unit (6) acquires a hydraulic cylinder stroke signal of the current stroke of the hydraulic cylinder (5) and feeds the hydraulic cylinder stroke signal back to the hydraulic cylinder telescopic distance determination device (2), the hydraulic cylinder telescopic distance determination device (2) judges whether the hydraulic cylinder is telescopic in place, if not, a new distance that the hydraulic cylinder needs to be telescopic is calculated according to the fed hydraulic cylinder stroke signal; and the electro-hydraulic proportional valve control signal generating unit (3) generates an updated electro-hydraulic proportional valve control signal according to the new distance.
3. The agricultural implement height control apparatus of claim 2, further comprising a display unit for displaying a current stroke of the hydraulic cylinder and/or a current height of the agricultural implement, wherein the cylinder displacement signal acquisition unit is a magnetostrictive displacement sensor.
4. An agricultural implement height control method comprising:
a target height value acquisition step, which is used for acquiring a target height value of the agricultural implement;
determining the telescopic distance of a hydraulic oil cylinder, namely determining the telescopic distance of a piston rod of the hydraulic oil cylinder according to the current stroke of the hydraulic oil cylinder and the functional relation between the stroke of the hydraulic oil cylinder and the suspension height;
an electro-hydraulic proportional valve control signal generation step, which generates an electro-hydraulic proportional valve control signal according to the determined distance,
wherein the agricultural implement suspension mechanism comprises a lower pull rod (8), a lifting rod (7) and a hook (9) arranged at the tail end of the extension part of the lower pull rod (8), one end of the hydraulic oil cylinder (5) is rotatably connected with the lower pull rod (8) through a connecting component, the other end of the hydraulic oil cylinder is rotatably connected with the lifting rod (7) through a connecting component, when a piston rod of the hydraulic oil cylinder (5) extends and retracts, the lifting rod (7) drives the lower pull rod (8) to rotate by taking the connecting part of the lower pull rod and the connecting component as a center,
wherein the lower pull rod (8), the lifting rod (7) and the hydraulic oil cylinder (5) are regarded as triangles, the functional relation between the stroke of the hydraulic oil cylinder and the suspension height is determined according to the geometric relation between the hydraulic oil cylinder and the agricultural implement suspension mechanism,
the function relation between the stroke of the hydraulic oil cylinder and the suspension height is as follows:
wherein
The initial length of hydraulic cylinder is l, and the piston rod stroke is delta l, the length AE of lifting rod is k1The length BE of the pull-down rod is k2Said lower pull rod extendsLength EI of long part being k3Setting the end point of the hydraulic oil cylinder close to the ground as B, extending the hydraulic oil cylinder to the intersection point with the ground along the length direction as C, wherein BC is equal to k4The included angle between the hydraulic oil cylinder and the ground is alpha.
5. The agricultural implement height control method of claim 4, further comprising a cylinder displacement signal acquisition step of acquiring a hydraulic cylinder stroke signal of a current stroke of the hydraulic cylinder and feeding back the hydraulic cylinder stroke signal for the hydraulic cylinder telescopic distance determination step.
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| CN201711201593.8A CN108401598B (en) | 2017-11-27 | 2017-11-27 | Method and device for accurately controlling three-point suspension height of tractor |
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| CN201711201593.8A CN108401598B (en) | 2017-11-27 | 2017-11-27 | Method and device for accurately controlling three-point suspension height of tractor |
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| CN108401598B true CN108401598B (en) | 2021-03-30 |
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| CN109854554B (en) * | 2018-08-30 | 2020-06-09 | 北京农业智能装备技术研究中心 | Rear suspension device of tractor and control method thereof |
| CN111923749A (en) * | 2020-08-20 | 2020-11-13 | 洛阳智能农业装备研究院有限公司 | Four-hub motor drive unmanned electric tractor control system |
| CN112567915B (en) * | 2020-12-16 | 2021-10-08 | 华中农业大学 | Hydraulic suspension device with double adjusting functions |
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| CN104541636A (en) * | 2014-12-30 | 2015-04-29 | 江苏大学 | Electric control method and electric control device for adjustment of hydraulic suspension position of tractor |
| CN204707435U (en) * | 2015-05-31 | 2015-10-21 | 石河子开发区锐益达机械装备有限公司 | A kind of hydraulic regulation suspension arrangement |
| CN106612682B (en) * | 2017-01-04 | 2019-02-05 | 江苏大学 | One kind being used for the adaptive lifting device of tractor electro-hydraulic hitch the edge of a field and control method |
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Address after: 241080 No.16, Anxi Road, Sanshan District, Wuhu City, Anhui Province Patentee after: Zhonglian Agricultural Machinery Co., Ltd Address before: 241080 No. 16 Emxi Road, Sanshan Economic Development Zone, Wuhu City, Anhui Province Patentee before: ZOOMLION HEAVY MACHINERY Co.,Ltd. |
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