Profiling hob mower, active and passive vibration reduction method and hob design method

Abstract

The invention provides a profiling hob mower, an active and passive vibration reduction method and a hob design method.Three hob mowing tools are arranged at the rear end of the mower in a staggered mode, hobs are controlled by an electric push rod and an electric push rod sliding block mechanism to achieve ground profiling, and magneto-rheological dampers are arranged on the electric push rod and the electric push rod sliding block mechanism to achieve active vibration reduction control; spraying rod postures are collected by tilt angle sensors arranged on the hobs, three ultrasonic ranging modules at the front end conduct distance measurement on the ground, signals are sent to a control unit, the control unit accurately controls the postures of the hobs, and rubber damping gaskets are arranged at the connecting positions of the left and right hobs and an electric push rod sliding block mechanism and the connecting positions of the hobs and electric push rods to achieve passive damping. The problems that the cutting height is uneven and the machine body vibrates too much under the complex terrain are solved through the profiling adjustment and multi-mode vibration reduction technology, passive vibration reduction is strengthened through an active vibration reduction mode, the stability of the hob is improved, energy is saved, and the multi-mode vibration reduction hob is suitable for efficient operation of hilly orchards and ridges.

Description

Technical Field

[0001] The present invention relates to the technical field of orchard machinery, and in particular to a profiling hob mower, a main and passive vibration damping method, and a hob design method. Background Art

[0002] The design of traditional spiral hob blades causes grass residues to scatter in the spiral direction, making it difficult to collect them centrally and requiring secondary cleaning, which increases the complexity of the operation. Especially in dense lawns, uneven accumulation of waste grass may affect the aesthetics of the lawn.

[0003] Existing mowers are prone to uneven cutting depths due to unstable power transmission in complex terrains (such as slopes and tall grass), and even power interruption may occur due to the equipment shoveling soil. In addition, the lack of a profiling adjustment mechanism results in inconsistent stubble heights and difficulty in adapting to ground undulations.

[0004] Therefore, reasonably solving the problem that it is difficult to ensure a flat cutting stubble and the stable operation of the mowing machine on undulating ground is an urgent problem to be solved. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the present invention provides a profiling hob mower, a main and passive vibration damping method, and a hob design method. Through profiling adjustment and main and passive vibration damping technologies, multi-modal composite vibration damping at the tool end is achieved, and through the coordinated control of ultrasonic ranging and the electric push rod slider mechanism, the tool is kept in contact with the ground contour at all times, achieving precise control of the cutting stubble height, improving the mowing quality and the stability of the equipment. The present invention also relates to a hob design method that can design the hob required by the present invention.

[0006] The present invention achieves the above technical objectives through the following technical means.

[0007] A profiling hob mower includes a frame and a hob actuator; the hob actuator is arranged at the rear side below the frame; the hob actuator includes three hobs, namely a first hob, a second hob, and a third hob. Among them, the first hob is placed in the middle, the second hob and the third hob are respectively placed on both sides of the first hob. The three hobs are respectively supported by one end of a hob support frame, and the other end of the hob support frame is rotationally connected to the frame through a rotating shaft. The middle section of the hob support frame is connected to the output end of an electric push rod, and the electric push rod is arranged on the frame; the telescopic movement of the electric push rod can drive the hob support frame to swing relative to the frame, thereby adjusting the height of the hob relative to the ground; the hob is driven to work by a hob drive motor; electric push rod slider mechanisms are arranged on the hob support frames where the second hob and the third hob are located. Among them, the output end of the electric push rod slider mechanism is connected to the second hob and the third hob through a rotating shaft and a slideway C; the operation of the electric push rod slider mechanism can drive the second hob and the third hob to swing up and down relative to the ground, thereby achieving ground profiling.

[0008] In the above solution, the electric push rod slider mechanism includes a driving rod, a push rod, a slideway A and a slideway B that are perpendicular to each other. Among them, the driving rod is slidably matched with the slideway A, the push rod is slidably matched with the slideway B, the driving rod and the push rod are connected by a connecting rod, and the connecting rod is hinged to the driving rod and the push rod respectively; the hob attitude driving motor drives the driving rod to slide along the slideway A through an intermediate rod, thereby driving the push rod to slide along the slideway B, thereby driving the connecting rod to swing up and down; the output end of the push rod is connected to the slideway C through a rotating shaft.

[0009] In the above solution, the slideway C is opened on the connecting rod, the connecting rod is a hollow tube, and two connecting rods are respectively installed on the input shafts of the second hob and the third hob. Among them, a hole is opened on the outer wall of one side of the connecting rod, and the hole is rotatably connected to the protruding shaft of the hob support frame.

[0010] In the above solution, a control unit and a data acquisition unit are further included; the data acquisition unit includes three ultrasonic ranging modules installed at the front end of the frame and an inclination sensor arranged at the hob input shaft; the data acquisition unit is used to collect ground height information and hob attitude data in real time; the control unit calculates the target hob height deviation through the data fusion of the ultrasonic ranging module and the inclination sensor, and issues displacement commands to the electric push rod and the electric push rod slider mechanism through the CAN bus.

[0011] In the above solution, the control unit uses a filtering algorithm to fuse and process the ultrasonic ranging data and the inclination sensor data, and generates a vibration damping command through a PID control algorithm.

[0012] In the above solution, a main and passive vibration damping system is further included. The main and passive vibration damping system includes a first magnetorheological damper and a second magnetorheological damper respectively arranged on the electric push rod and the electric push rod slider mechanism, and rubber shock pads arranged at the connection between the hob and the connecting rod and on the electric push rod slider mechanism.

[0013] In the above solution, the damping coefficients of the first magnetorheological damper and the second magnetorheological damper are steplessly variable within 10 - 500 Ns / m through current adjustment. The rubber shock pads are made of natural rubber with a hardness of 70 ± 5 Shore A and are used to attenuate vibrations in the frequency band of 100 - 500 Hz.

[0014] The main and passive composite vibration damping method for a profiling hob mower includes the following steps: real-time collecting the ground height data in front through an ultrasonic ranging module; obtaining the real-time attitude data of the hob through an inclination sensor; the control unit fusing the ranging and attitude data, calculating the target tool height deviation and damping adjustment parameters; sending displacement instructions to the electric push rod and the electric push rod slider mechanism to adjust the height and inclination of the hob; dynamically adjusting the currents of the first magnetorheological damper and the second magnetorheological damper according to the vibration frequency to achieve active vibration damping; passively attenuating high-frequency vibrations through rubber shock pads and spring washers to form main and passive composite vibration damping.

[0015] A hob design method, where the hob is used for a profiling hob mower,

[0016] Step 1: The hob blade is designed with a centrosymmetric spiral, the first blade angle is α1 and the second blade angle is α2, and α1 = α2; the blade angle design is based on the formula F = (σ·t·sinα) / (μ + sinα), and the value of the first blade angle is 11.5° to 30°;

[0017] Step 2: Combining the stroke L of the electric push rod and the radius R of the hob, the range of inclination angle change is calculated through geometric relations: θ = arcsin(L / R) = arcsin(80 / R), and R = 80 / sin(θ), and the reasonable design range of θ is 5° to 15°; the inclination angle of the hob blade is 90 - θ, that is, 75° to 85°;

[0018] Step 3: The radius of the hob is 80.31 to 82.83 mm.

[0019] In the above scheme, the value of the first blade angle is 20°, the value of the hob radius is 82 mm, and the relative penetration angle β of the blade into the grass stem is based on the formula β = tan -1 (Vx / Vy), where Vx is the horizontal cutting speed of the blade (m / s), according to the formula Vx = ωR, ω is the angular velocity of the blade (rad / s), Vy is the vertical speed of the blade relative to the grass leaf (m / s), and the formula Vy = Vx×tan(90 - θ). After calculation, when the hob mower maintains a hob rotation speed of 3000 rpm, the relative penetration angle of the blade into the grass stem can be maintained at 13.77°

[0020] Beneficial effects:

[0021] Applicable Scenarios and Advantages This invention is applicable to orchard terrain scenarios. Compared with traditional lawn mowers, it has the following advantages: - Height Adaptability: It can achieve precise profiling within a range of ±80 mm, and the fluctuation of the cutting stubble height meets the requirements of agricultural and forestry operations. - High-efficiency Vibration Reduction: Active + passive composite vibration reduction significantly reduces the additional excitation caused by environmental factors, effectively improving the service life and operation accuracy of the equipment. - Energy Conservation and Environmental Protection: By actively controlling the damping change of the magnetorheological damper for suppressing high-frequency amplitudes, compared with the traditional drive damping system for suppressing high-frequency amplitudes, the overall energy consumption can be greatly reduced, while also meeting the requirements of stable operation. Description of the Drawings

[0022] Figure 1 It is a three-dimensional structure schematic diagram related to an embodiment of the present invention;

[0023] Figure 2 It is a top view of removing the outer shell related to an embodiment of the present invention;

[0024] Figure 3 It is a front view of removing the outer shell related to an embodiment of the present invention;

[0025] Figure 4 It is a schematic diagram of the hob attitude profiling structure related to an embodiment of the present invention;

[0026] Figure 5 It is a schematic diagram of the hob structure related to an embodiment of the present invention;

[0027] Figure 6 It is a schematic diagram of the hob profiling with respect to the ground related to an embodiment of the present invention.

[0028] Reference Signs:

[0029] 1 - Frame; 2 - Battery Box; 3 - Wheels; 4 - Hob Electric Push Rod; 5 - Hob Support Frame; 6 - Hob Attitude Drive Motor; 7 - Hob Electric Push Rod Slide Block Mechanism; 8 - Hob; 9 - Inclination Sensor; 10 - Fuel Tank; 11 - Spring Washer; 12 - Infrared Distance Measuring Module; 13 - Extension Shaft; 14 - Hob Drive Motor; 15 - First Magnetorheological Damper; 16 - Rubber Washer; 17 - Control Unit; 18 - Drive Unit; 19 - Push Rod; 20 - Active Rod; 21 - Second Magnetorheological Damper; 22 - First Blade Angle; 23 - Second Blade Angle; 24 - Hob Radius; 25 - Hob Blade Inclination Angle; 26 - Angle of Blade Relative to Grass Stem Penetration; Vx - Horizontal Cutting Speed of Blade (m / s), Vy - Vertical Speed of Blade Relative to Grass Leaf (m / s); 27 - Slideway A; 28 - Connecting Rod; 29 - Slideway B; 30 - Slideway C. Detailed Embodiment

[0030] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "axial", "radial", "vertical", "horizontal", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These are only for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0032] In the present invention, unless otherwise clearly specified and defined, the terms "mounted", "connected", "coupled", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] Combined with the attached Figure 1 As shown, a profiling hob mower according to the present invention includes a frame 1, a battery box 2, a fuel tank 10, a hob actuator, a control unit 17, a data acquisition unit, and a drive unit 18;

[0034] The hob actuator includes three hobs 8, which are arranged transversely and staggered at the rear end of the frame 1. Among them, the left and right hobs are located at the rear, and the middle hob is located at the front. The overlapping area between the three hobs is 20 - 50 mm; each hob 8 is connected to the frame 1 through an independent electric push rod 4, and a first magnetorheological damper 15 is integrated on the electric push rod 4. The current is adjusted by the control unit 17 to change the damping characteristics in real time, so as to achieve active vibration damping for the high-frequency vibration of the three hobs and the hob support frame 5 relative to the rotation direction of the frame.

[0035] The hob follows the contour of the ground. The left and right hobs 8-A and 8-C are articulated to the electric push rod slider mechanism 7 through the connecting rod 40 and are driven by the hob attitude driving motor 6. The electric push rod slider mechanism 7 adopts a double-guide structure, which is composed of mutually perpendicular slideways A27 and slideway B29. Among them, the active rod 20 is slidably matched with the slideway A27, and the push rod 19 is slidably matched with the slideway B29; the active rod 20 and the push rod 19 are connected by the connecting rod 28, and the connecting rod 28 is respectively articulated to the active rod 20 and the push rod 19. The stroke of the push rod 19 is ±80 mm, so that the hob swings up and down with the terrain to achieve ground contour following; a second magnetorheological damper 21 is provided at the end of the electric push rod slider mechanism 7, and the current is adjusted through the control unit 17 to change the damping characteristics in real time, aiming at the up and down swing of the hob relative to the hob support frame 5 caused by the external force received during operation and the vibration of the fuselage itself, so as to achieve active vibration damping;

[0036] The data acquisition unit includes three ultrasonic ranging modules 12 installed at the front end of the frame 1 and an inclination sensor 9 arranged at the hob rotating shaft, which are used to collect ground height information and hob attitude data in real time;

[0037] The control unit 17 calculates the target tool height deviation through the control algorithm by fusing the data of the ultrasonic ranging module 12 and the inclination sensor 9, and issues displacement and damping commands to the electric push rod 4 and the electric push rod slider mechanism 7 through the CAN bus, so that the deviation between the inclination angle of the hob 8 and the ground normal line does not exceed 5°;

[0038] The main and passive composite vibration damping system includes an active vibration damping component composed of a magnetorheological damper 15 integrated with an independent electric push rod on each hob and a second magnetorheological damper 21 provided at the end of the electric push rod slider mechanism 7, and its damping coefficient is steplessly variable within the range of 10-500 Ns / m through current adjustment; rubber shock pads 16 are arranged at the connection between the hob 8 and the connecting rod and at the electric push rod slider mechanism, and natural rubber with a hardness of 70±5 Shore A is selected to attenuate the vibration in the frequency band of 100-500 Hz. The damping coefficient c of the magnetorheological damper is 10-500 Ns / m, and it is necessary to suppress the vibration amplitude of the hob ≤2 mm. According to the vibration equation: Assume the natural frequency f of the system n = 50 Hz, and the damping ratio ζ = c / 2√(mk). It can be calculated that when c = 500 Ns / m, ζ≈0.7, which can effectively suppress resonance.

[0039] The hob combines with attachments Figure 5 and attachments Figure 6As shown in the figure, the hob blade is designed with a centrally symmetric spiral, so the first blade angle 22 is equal to the second blade angle 23, α1 = α2. The blade angle design is based on the formula F = (σ·t·sinα) / (μ + sinα), where the friction coefficient μ between cork / hardwood and stainless steel can be obtained from the table as (0.2 - 0.5), the thickness t of the grass stem is assumed to be 2mm, and the shear strength σ of the grass stem is assumed to be 50 Mpa. After calculation, the blade angle is 11.5° - 30°. Considering the actual operation requirements and processing costs, the present invention decides to design the hob blade angle as 20°. The inclination angle 25 of the hob blade needs to meet the profiling requirements under the terrain undulation of ±80mm. Combining the push rod stroke and the hob radius 24 (R), the change range of the inclination angle can be calculated through geometric relationship: θ = arcsin(L / R) = arcsin(80 / R), so R = 80 / sin(θ). The reasonable design range of the inclination angle θ of the traditional cutter head mower is 5° - 15°. The actual ideal inclination angle of the hob involved in the present invention is 90 - θ (75° - 85°). Therefore, in the ideal state, the hob radius is 80.31 - 82.83mm. Considering the actual situation, the present invention designs the hob radius as 82mm. The relative penetration angle 26 (β) of the blade into the grass stem, β = tan -1 (Vx / Vy), where Vx is the horizontal cutting speed of the blade (m / s), Vx = ωR, ω is the angular velocity of the blade (rad / s), Vy is the vertical speed of the blade relative to the grass leaf (m / s), Vy = Vx×tan(90 - θ). After calculation, when the hob mower of the present invention maintains a hob rotation speed of 3000 rpm, the relative penetration angle of the blade into the grass stem can be maintained at 13.77°.

[0040] In the description of this specification, the descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0041] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention without departing from the principles and purposes of the present invention.

Claims

1. A profiling hob mower, characterized in that, It includes a frame (1) and a hob actuator; the hob actuator is arranged at the rear side below the frame (1); The hob actuator includes three hobs (8), namely the first hob, the second hob and the third hob. Among them, the first hob is placed in the middle, the second hob and the third hob are respectively placed on both sides of the first hob. The three hobs are respectively supported by one end of a hob support frame (5), and the other end of the hob support frame (5) is rotationally connected to the frame (1) through a rotating shaft. The middle section of the hob support frame (5) is connected to the output end of an electric push rod (4), and the electric push rod (4) is arranged on the frame (1); the telescopic movement of the electric push rod (4) can drive the hob support frame (5) to swing relative to the frame (1) so as to adjust the height of the hob (3) relative to the ground; the hob (8) is driven to work by a hob drive motor (14); Electric push rod slider mechanisms (7) are arranged on the hob support frames (5) where the second hob and the third hob are located. Among them, the output end of the electric push rod slider mechanism (7) is connected to the second hob and the third hob through a rotating shaft and a slideway C (30); the work of the electric push rod slider mechanism (7) can drive the second hob and the third hob to swing up and down relative to the ground so as to realize ground profiling.

2. The profiling hob mower according to claim 1, characterized in that, The electric push rod slider mechanism (7) includes a driving rod (20), a push rod (19), mutually perpendicular slideways A (27) and slideways B (29). Among them, the driving rod (20) is slidably matched with the slideway A (27), the push rod (19) is slidably matched with the slideway B (29), the driving rod (20) and the push rod (19) are connected by a connecting rod (28), and the connecting rod (28) is respectively hinged to the driving rod (20) and the push rod (19); the hob attitude drive motor (6) drives the driving rod (20) to slide along the slideway A (27) through an intermediate rod, drives the push rod (19) to slide along the slideway B (29), and thus drives the connecting rod (28) to swing up and down; the output end of the push rod (19) is connected to the slideway C (30) through a rotating shaft.

3. The profiling hob mower according to claim 2, characterized in that The slideway C (30) is opened on a connecting rod. The connecting rod is a hollow tube. The two connecting rods are respectively installed on the input shafts of the second hob and the third hob. Among them, a hole is opened on the outer wall of one side of the connecting rod, and the hole is rotationally connected to the protruding shaft (13) of the hob support frame (5).

4. The profiling hob mower according to claim 1, wherein It also includes a control unit (17) and a data acquisition unit; the data acquisition unit includes three ultrasonic ranging modules (12) installed at the front end of the frame (1) and an inclination sensor (9) arranged at the hob input shaft; the data acquisition unit is used to collect ground height information and hob attitude data in real time; the control unit (17) calculates the target hob height deviation through fusing the data of the ultrasonic ranging module (12) and the inclination sensor (9), and issues displacement instructions to the electric push rod (4) and the electric push rod slider mechanism (7) through the CAN bus.

5. The profiling hob mower according to claim 4, characterized in that, The control unit (17) uses a filtering algorithm to fuse and process the ultrasonic ranging data and the inclination sensor data, and generates a vibration reduction instruction through a PID control algorithm.

6. The profiling hob mower according to claim 1, wherein, It also includes a primary and secondary vibration damping system. The primary and secondary vibration damping system includes a first magnetorheological damper (15) and a second magnetorheological damper (21) respectively arranged on the electric push rod (4) and the electric push rod slider mechanism (7), and rubber shock pads (16) arranged at the connection between the hob (8) and the connecting rod and on the electric push rod slider mechanism (7).

7. The profiling hob mower according to claim 6, characterized in that, The damping coefficients of the first magnetorheological damper (15) and the second magnetorheological damper (21) are steplessly variable within 10 - 500 Ns / m by adjusting the current. The rubber shock pads (16) are made of natural rubber with a hardness of 70 ± 5 Shore A and are used to attenuate vibrations in the frequency band of 100 - 500 Hz.

8. The method for active and passive composite vibration reduction of a profiling hob mower according to any one of claims 4 to 7, characterized in that It includes the following steps: real-time collect the ground height data in front through the ultrasonic ranging module (12); obtain the real-time attitude data of the hob (8) through the inclination sensor (9); the control unit (17) fuses the ranging and attitude data, calculates the target tool height deviation and the damping adjustment parameters; sends displacement commands to the electric push rod (4) and the electric push rod slider mechanism (7) to adjust the height and inclination of the hob; dynamically adjust the current of the first magnetorheological damper (15) and the second magnetorheological damper (20) according to the vibration frequency to achieve active vibration damping; passively attenuate high-frequency vibrations through the rubber shock pads (16) and spring washers (11) to form a primary and secondary composite vibration damping.

9. A hob design method, characterized in that, The hob is used for the profiling hob mower described in claims 1 - 8, Step 1: The hob blade is designed with a centrally symmetric spiral. The first blade angle (22) is α1 and the second blade angle (23) is α2, and α1 = α2; the blade angle design is based on the formula F = (σ·t·sinα) / (μ + sinα), and the value of the first blade angle (22) is 11.5° - 30°; Step 2: Combining the stroke L of the electric push rod and the radius R of the hob, the variation range of the inclination angle is calculated through geometric relationships: θ = arcsin(L / R) = arcsin(80 / R), and R = 80 / sin(θ). The reasonable design range of θ is 5° - 15°; the inclination angle (25) of the hob blade is 90 - θ, that is, 75° - 85°; Step 3: The radius (24) of the hob is 80.31 - 82.83 mm.

10. The hob design method according to claim 9, wherein The first blade angle (22) is 20°, the hob radius (24) is 82 mm, and the blade relative to the grass stem penetration angle β (26) is calculated according to the formula β = tan -1 (Vx / Vy), where Vx is the horizontal cutting speed of the blade (m / s), calculated according to the formula Vx = ωR, ω is the angular velocity of the blade (rad / s), Vy is the vertical speed of the blade relative to the grass blade (m / s), and the formula Vy = Vx × tan(90 - θ). After calculation, when the rotary mower maintains a hob speed of 3000 rpm, the blade relative to the grass stem penetration angle can be maintained at 13.77°.

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