Garden tool and control method thereof

Abstract

The present application belongs to the field of garden tools, and particularly relates to a garden tool and a control method thereof, which comprises a steering wheel, a first angle sensor, a control module, and drive elements of two drive wheels, wherein the steering wheel is in transmission connection with the first angle sensor through a speed reduction transmission mechanism, the first angle sensor is in electrical connection with the control module, and the control module is in electrical connection with the drive elements of the two drive wheels; in the vehicle control system, at least one angle sensor is used to generate an actual position signal indicating the position state of the steering wheel, instead of the inferred or expected position of the steering wheel, so that the response speed and response accuracy can be effectively improved; the speed reduction transmission is used to avoid the problem of excessively sensitive sensor potential value change caused by slight rotation of the steering wheel and some idle strokes of the transmission structure, and the smooth and stable machine control at zero steering is ensured.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of garden tools, in particular to a garden tool and a control method thereof. BACKGROUND

[0002] In order to ensure the flexibility of movement, garden tools such as lawn mowers and snow blowers generally require to realize steering operation with a small radius, even zero radius steering operation. In the prior art, steering operation is generally realized by controlling the deflection angle of the front wheel. Such steering structure is relatively complex in the transmission mechanism when realizing zero radius steering. In addition, there is relative sliding friction between the rear wheel and the ground during steering, which will cause damage to the lawn. SUMMARY

[0003] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a garden tool capable of flexibly controlling the turning radius and having a simple structure, and a control method thereof.

[0004] To achieve the above-mentioned purpose and other related purposes, the present application provides a garden tool, comprising:

[0005] A chassis, wherein a universal wheel and at least two drive wheels are installed on the chassis, one of the universal wheel and the drive wheels is located at the front of the chassis, and the other is located at the rear of the chassis;

[0006] A steering wheel, which is rotationally connected with the chassis;

[0007] A first angle sensor, wherein the steering wheel is drivingly connected with the first angle sensor through a speed reduction transmission mechanism;

[0008] A control module, wherein the first angle sensor is electrically connected with the control module, and the control module is electrically connected with the drive elements of the two drive wheels, respectively;

[0009] The control module is configured to:

[0010] When the rotation angle of the first angle sensor is located in a first preset interval, the control module controls the two drive wheels to rotate at the same speed;

[0011] When the rotation angle of the first angle sensor is located in a second preset interval, the control module controls the two drive wheels to rotate at the same speed;

[0012] When the rotation angle of the first angle sensor is located in a third preset interval, the control module controls the two drive wheels to rotate in opposite directions;

[0013] Wherein the second preset interval is distributed at both ends of the first preset interval, and the third preset interval is distributed at both ends of the union of the first preset interval and the second preset interval.

[0014] In an optional embodiment of the present application, the speed reduction mechanism comprises:

[0015] The first transmission shaft is fixedly connected with the steering wheel and rotationally connected with a steering bracket arranged on the garden tool;

[0016] The second transmission shaft is rotationally connected with the chassis of the garden tool, one end of the second transmission shaft is synchronously rotationally connected with the first transmission shaft through a universal joint, and the other end of the second transmission shaft is provided with a first gear;

[0017] The second gear is rotationally connected with the chassis of the garden tool, the second gear is engaged with the first gear, and the diameter of the second gear is greater than that of the first gear;

[0018] The swing arm has one end connected with the first angle sensor and the other end connected with the second gear.

[0019] In an optional embodiment of the present application, the second preset interval comprises a first sub-interval and a second sub-interval arranged at two ends of the first preset interval;

[0020] When the rotation angle of the first angle sensor is located in the first sub-interval, the control module controls the rotation speed of the left drive wheel to be less than that of the right drive wheel;

[0021] When the rotation angle of the first angle sensor is located in the second sub-interval, the control module controls the rotation speed of the right drive wheel to be less than that of the left drive wheel.

[0022] In an optional embodiment of the present application, the third preset interval comprises a third sub-interval and a fourth sub-interval, and the third sub-interval and the fourth sub-interval are arranged at two ends of a union of the first preset interval and the second preset interval;

[0023] When the rotation angle of the first angle sensor is located in the third sub-interval, the control module controls the left drive wheel to rotate reversely;

[0024] When the rotation angle of the first angle sensor is located in the fourth sub-interval, the control module controls the right drive wheel to rotate reversely.

[0025] In an optional embodiment of the present application, the first preset interval is [-1°, +1°].

[0026] In an optional embodiment of the present application, the second preset interval is [-11°, -1°)∪(+1°, +11°], wherein the first sub-interval is [-11°, -1°) and the second sub-interval is (+1°, +11°].

[0027] In an optional embodiment of the present application, the third preset interval is [-21°, -11°)∪(+11°, +21°], wherein the third sub-interval is [-21°, -11°) and the fourth sub-interval is (+11°, +21°].

[0028] In an optional embodiment of the present application, the control device further comprises:

[0029] an accelerator pedal;

[0030] a second angle sensor, the accelerator pedal being drivingly connected to the second angle sensor through a linkage mechanism, and the second angle sensor being electrically connected to the control module.

[0031] The control module is configured to control the rotational speed of the driving wheels to increase when the rotational angle of the second angle sensor increases.

[0032] In an optional embodiment of the present application, when the rotational angle of the first angle sensor is within the first preset interval, the rotational speed N L of the left driving wheel and the rotational speed N R of the right driving wheel satisfy:

[0033] N L =N R =(N max / (U max -U min ))*(U2-U min ).

[0034] wherein N max represents the maximum rotational speed of the driving wheels, U max represents the maximum output voltage of the second angle sensor, U min represents the minimum output voltage of the second angle sensor, and U2 represents the real-time output voltage of the second angle sensor; the output voltage of the second angle sensor increases with the increase of the rotational angle of the second angle sensor.

[0035] In an optional embodiment of the present application, when the rotational angle of the first angle sensor is within the first sub-interval, the rotational speed N L of the left driving wheel and the rotational speed N R of the right driving wheel satisfy:

[0036] N R = (N max / (U max -U min ))*(U2-U min );

[0037] N L = ((U1-U a ) / (U b -U a ))*N R ;

[0038] wherein N max represents the maximum rotation speed of the driving wheel, U max represents the maximum output voltage of the second angle sensor, U min represents the minimum output voltage of the second angle sensor, U2 represents the real-time output voltage of the second angle sensor, U a and U b respectively represent the minimum output voltage and the maximum output voltage of the first angle sensor when the rotation angle of the first angle sensor is located in the first sub-interval, and the U1 represents the real-time output voltage of the first angle sensor; the real-time output voltage U1 of the first angle sensor increases with the increase of the rotation angle of the first angle sensor, and the real-time output voltage U2 of the second angle sensor increases with the increase of the rotation angle of the second angle sensor.

[0039] In an optional embodiment of the present application, when the rotation angle of the first angle sensor is located in the second sub-interval, the rotation speed N L of the left driving wheel and the rotation speed N R of the right driving wheel satisfy:

[0040] N L = (N max / (U max -U min ))*(U2-U min );

[0041] N R = ((U d -U1) / (U d -U c ))*N L ;

[0042] wherein N max represents the maximum rotation speed of the driving wheel, U max represents the maximum output voltage of the second angle sensor, U minrepresents the minimum output voltage of the second angle sensor, U2 represents the real-time output voltage of the second angle sensor, U c and U d respectively represent the minimum output voltage and the maximum output voltage of the first angle sensor when the rotation angle of the first angle sensor is located in the second sub-interval, and U1 represents the real-time output voltage of the first angle sensor; the real-time output voltage U1 of the first angle sensor increases with the increase of the rotation angle of the first angle sensor, and the real-time output voltage U2 of the second angle sensor increases with the increase of the rotation angle of the second angle sensor.

[0043] In an optional embodiment of the present application, when the rotation angle of the first angle sensor is located in the third sub-interval, the rotation speed N L of the left driving wheel and the rotation speed N R of the right driving wheel satisfy:

[0044] N R =(N max / (U max -U min ))*(U2-U min );

[0045] N L =-((U f -U1) / (U f -U e ))*N R ;

[0046] wherein N max represents the maximum rotation speed of the driving wheel, U max represents the maximum output voltage of the second angle sensor, U min represents the minimum output voltage of the second angle sensor, U2 represents the real-time output voltage of the second angle sensor, U e and U f respectively represent the minimum output voltage and the maximum output voltage of the first angle sensor when the rotation angle of the first angle sensor is located in the third sub-interval, and U1 represents the real-time output voltage of the first angle sensor; the real-time output voltage U1 of the first angle sensor increases with the increase of the rotation angle of the first angle sensor, and the real-time output voltage U2 of the second angle sensor increases with the increase of the rotation angle of the second angle sensor.

[0047] In an optional embodiment of the present application, when the rotation angle of the first angle sensor is located in the fourth sub-interval, the rotation speed N Land the rotation speed N of the right drive wheel R satisfies:

[0048] N L = (N max / (U max -U min ))*(U2-U min );

[0049] N R = -((U 1- U g ) / (U h -U g ))*N L ;

[0050] wherein N max represents the maximum rotation speed of the drive wheel, U max represents the maximum output voltage of the second angle sensor, U min represents the minimum output voltage of the second angle sensor, U2 represents the real-time output voltage of the second angle sensor, U g and U h respectively represent the minimum output voltage and the maximum output voltage of the first angle sensor when the rotation angle of the first angle sensor is in the fourth sub-interval, and the U1 represents the real-time output voltage of the first angle sensor; the real-time output voltage U1 of the first angle sensor increases with the increase of the rotation angle of the first angle sensor, and the real-time output voltage U2 of the second angle sensor increases with the increase of the rotation angle of the second angle sensor.

[0051] To achieve the above object and other related objects, the present application further provides a garden tool control method, wherein the garden tool comprises a first angle sensor for identifying the rotation of a steering wheel, the first angle sensor is electrically connected with a control module, the control module is electrically connected with a left drive wheel and a right drive wheel respectively, and the method comprises the following steps:

[0052] obtaining a detection signal of the first angle sensor;

[0053] controlling the rotation speed of the left drive wheel and the right drive wheel according to the detection signal, comprising:

[0054] when the rotation angle of the steering wheel to the left or to the right is less than or equal to a first preset value, controlling the left drive wheel and the right drive wheel to rotate at the same speed;

[0055] when the steering wheel rotates to the left, and the rotation angle is greater than the first preset value and less than or equal to a second preset value, controlling the rotation speed of the left drive wheel to be lower than that of the right drive wheel;

[0056] when the steering wheel is turned to the left and the turning angle is greater than the second preset value, the left driving wheel is controlled to turn backward;

[0057] when the steering wheel is turned to the right and the turning angle is greater than the first preset value and less than or equal to the second preset value, the speed of the right driving wheel is controlled to be lower than that of the left driving wheel;

[0058] when the steering wheel is turned to the right and the turning angle is greater than the second preset value, the right driving wheel is controlled to turn backward.

[0059] The technical effect of the present application is that the present application generates an actual position signal indicating the position state of the steering wheel in the vehicle control system by using at least one angle sensor, rather than the inferred or expected position of the steering wheel, thereby effectively improving the response speed and response accuracy; the present application uses the steering input device (such as the steering wheel) to input the operation intention of the operator, and detects the actual position of the steering input device through an angle sensor, and generates a signal, which is processed by a control module to control one or more drivable structures of the vehicle, so that the driving motor realizes the forward and reverse rotation of the left and right wheels through the gear box, and the universal wheel changes the turning angle with the control of the left and right rear wheel speed and steering during steering; the present application avoids the problem of excessive sensitivity of the sensor potential value caused by the slight rotation of the steering wheel and the dead stroke of the transmission structure through deceleration transmission, and ensures smooth and stable operation of the machine during zero steering. BRIEF DESCRIPTION OF DRAWINGS

[0060] Figure 1 is a perspective view of the lawn mower provided by the embodiment of the present application;

[0061] Figure 2 is a top view of the lawn mower provided by the embodiment of the present application;

[0062] Figure 3 is a transmission structure diagram of the control device provided by the embodiment of the present application;

[0063] Figure 4 is a perspective view of the deceleration transmission mechanism provided by the embodiment of the present application;

[0064] Figure 5 is a perspective view of the connecting rod transmission mechanism provided by the embodiment of the present application;

[0065] Figure 6 is a control principle diagram of the lawn mower in the straight running state provided by the embodiment of the present application;

[0066] Figure 7 is a control principle diagram of the lawn mower in the left ordinary steering state provided by the embodiment of the present application;

[0067] Figure 8 is a control principle diagram of the mower in a left zero-radius turning state provided by an embodiment of the present application;

[0068] Figure 9 is a flow chart of a turning control method of the mower provided by an embodiment of the present application;

[0069] Figure 10 is a principle diagram of the mower in a normal turning state provided by an embodiment of the present application;

[0070] Figure 11 is a principle diagram of the mower in a zero-radius turning state provided by an embodiment of the present application;

[0071] Figure 12 is a curve diagram of the voltage of the angle sensor varying with the angle provided by an embodiment of the present application;

[0072] Figure 13 is a schematic diagram of the interval division of the angle sensor provided by an embodiment of the present application;

[0073] Figure 14 is a schematic diagram of the corresponding relationship between the voltage and the angle provided by an embodiment of the present application. DETAILED DESCRIPTION

[0074] The other advantages and effects of the present application can be easily understood by those skilled in the art from the content disclosed in the present specification. The present application can also be implemented or applied by using different specific embodiments, and each detail in the present specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0075] It should be noted that the diagrams provided in the following embodiments only schematically illustrate the basic concept of the present application, and only the components related to the present application are shown in the diagrams, not the number, shape and size of the components in actual implementation. The type, number and proportion of each component in actual implementation can be randomly changed, and the layout type of the components can be more complex.

[0076] Please refer to Figures 1-14 The technical solutions of the present application will be described in detail below in combination with a mower. It should be understood that the control device and the control method provided by the present application are not only applicable to the mower, but also can be applied to other garden tools such as snow blower.

[0077] Please refer to Figure 1 , 2As shown in the figure, a mower comprises a chassis 10, universal wheels 11, drive wheels 12 and a control device, specifically, the universal wheels 11 are installed at the front end of the chassis 10; the drive wheels 12 are provided with two, and the two drive wheels 12 are respectively arranged on the left and right sides of the chassis 10. It can be understood that the front and rear positional relationship of the universal wheels 11 and the drive wheels 12 is not unique, for example, in some embodiments, the drive wheels 12 can also be arranged at the front end of the chassis 10, and the universal wheels 11 can be arranged at the rear end of the chassis 10; the number of the universal wheels 11 is also not unique, for example, in some embodiments, the universal wheels 11 can be arranged with only one.

[0078] It can be understood that the mower further comprises a cutting assembly 50, in the embodiment, the cutting assembly 50 is located below the middle part of the chassis 10, and similarly, the arrangement mode of the cutting assembly 50 can also be freely selected according to actual needs, for example, the cutting assembly 50 can also be installed at the front end or the rear end of the chassis 10. In the embodiment, the chassis 10 is further provided with a seat 101 for an operator to sit on, but it can be understood that the seat 101 is not necessary for the mower, for example, the operator can also operate the mower in a standing posture.

[0079] Please refer to Figures 3-8 As shown in the figure, the control device comprises a steering wheel 20, a first angle sensor 25 and a control module 60.

[0080] Please refer to Figure 3 , 4 As shown in the figure, the steering wheel 20 is rotatably arranged above the chassis 10; it can be understood that the steering wheel 20 of the present application does not directly drive the wheels to rotate, but only serves as an input device, so that the control module 60 can determine the intention of the operator according to the rotation of the steering wheel 20.

[0081] Please refer to Figure 3 , 4 As shown in the figure, the first angle sensor 25 is in transmission connection with the steering wheel 20 to identify the rotation of the steering wheel 20; the angle sensor of the present application is a device capable of converting mechanical movement into new signals, specifically a device capable of outputting different voltages according to the change of angle, and the voltage and the angle are in linear relationship, such as Figure 12 As shown in the figure, the control module 60 can determine the rotation angle of the angle sensor according to the voltage change of the angle sensor.

[0082] Please refer to 6-11, the control module 60 is connected with the detection signal output end of the first angle sensor 25, and the control module 60 is connected with the control signal input end of the drive wheel 12, the control module 60 is configured to: when the rotation angle of the first angle sensor 25 is in the first preset interval A, the control module 60 controls the two drive wheels 12 to rotate at the same speed; when the rotation angle of the first angle sensor 25 is in the second preset interval B, the control module 60 controls the two drive wheels 12 to rotate at the same speed. Differentiate; when the rotation angle of the first angle sensor 25 is in the third preset interval C, the control module 60 controls the two drive wheels 12 to rotate in opposite directions; wherein the second preset interval B is distributed at both ends of the first preset interval A, and the third preset interval C is distributed at both ends of the union of the first preset interval A and the second preset interval B. It can be understood that the steering wheel 20 is drivingly connected with the first angle sensor 25 through a speed reduction transmission mechanism, and the rotation angle of the first angle sensor 25 will change synchronously according to the rotation angle of the steering wheel 20 in a certain proportion, so that the angle change of the first angle sensor 25 can objectively reflect the driving intention of the operator. Because a speed reduction transmission mechanism is adopted, the steering wheel 20 rotates a large stroke to cause the detection data of the first angle sensor 25 to change obviously, which can avoid the first angle sensor 25 from being triggered by slight shaking of the steering wheel 20 on the one hand, and can make the steering angle control more smooth and improve the control precision on the other hand. In addition, the first angle sensor 25 has a certain idle stroke near the initial position, for example, when the detection angle of the first angle sensor 25 is within ±1°, the control module 60 does not respond, preventing the steering from being too sensitive and exceeding the user's operation expectation, and also reducing the deviation between different machines. When the detection angle of the first angle sensor 25 is in this area, the rotation speeds of the left and right wheels are the same, and the direction is determined by the gear switching switch.

[0083] Figure 10 and Figure 11 is a schematic top view of a vehicle steering showing its ability to achieve substantially ideal Ackerman steering. Figure 10 showing a non-zero radius turn, Figure 11 showing a zero radius turn. The front wheels travel Figure 10 along two different arcuate paths A1 and A2 when turning as described in the background, which would theoretically have a common center point C. Theoretically, by controlling the speed of the left and right wheels, differential steering of the left and right wheels can be achieved, avoiding the rubber on the tire from wearing off or damaging the plants under the front wheels.

[0084] The present application generates actual position signals indicating the position state of the steering wheel 20 in the vehicle control system by using at least one angle sensor, instead of the inferred or expected position of the steering wheel 20, so as to effectively improve the response speed and response accuracy; the present application uses the steering input device (such as the steering wheel 20) to input the operation intention of the operator, and detects the actual position of the steering input device by using an angle sensor, and generates signals, which are processed by the control module 60 to control one or more drivable structures of the vehicle, so that the drive motor realizes the forward and reverse rotation of the left and right wheels through the gear box, and the universal wheel 11 changes the turning angle with the control of the left and right rear wheel speed and steering when steering; the present application avoids the problem that the sensor potential value is too sensitive due to the slight rotation of the steering wheel 20 and the dead stroke of the transmission structure, and ensures smooth and stable machine operation when steering.

[0085] Please refer to Figure 3 、 4 , in an optional embodiment of the present application, the speed reduction transmission mechanism includes a first transmission shaft 21, a second transmission shaft 22, a second gear 24 and a swing arm 251. Specifically, the first transmission shaft 21 is fixedly connected with the steering wheel 20 and rotationally connected with the steering wheel 20 support provided on the garden tool; the second transmission shaft 22 is rotationally connected with the chassis 10 of the garden tool, one end of the second transmission shaft 22 is synchronously rotationally connected with the first transmission shaft 21 through a universal joint, and the other end of the second transmission shaft 22 is provided with a first gear 221; the second gear 24 is rotationally connected with the chassis 10 of the garden tool, the second gear 24 is engaged with the first gear 221, and the diameter of the second gear 24 is greater than that of the first gear 221; one end of the swing arm 251 is connected with the first angle sensor 25, and the other end of the swing arm 251 is connected with the second gear 24. Specifically, the first angle sensor 25 includes a body and a detection shaft, the detection shaft is rotationally arranged relative to the body, and a detection element for recognizing the rotation angle of the detection shaft is arranged in the body; the swing arm 251 is connected with the detection shaft, and can transmit the rotary motion of the steering wheel 20 to the detection shaft in real time, so as to detect the rotation angle of the steering wheel 20. The present application has the advantages of simple structure, low manufacturing cost, simple and convenient installation, and the use of the universal wheel 11 structure reduces the manufacturing difficulty, releases the limitation of the front wheel steering angle, and theoretically approaches the zero turning radius.

[0086] Please refer to Figure 3 、 4As shown, in one specific embodiment, the second gear 24 is a sector gear. The center of the sector of the second gear 24 is provided with a rotating shaft, which is rotatably connected to the chassis 10. An arc-shaped hole 241 is provided on the sector surface of the second gear 24, with the center of the arc 241 coinciding with the center of the sector. A guide pin 14 is provided on the chassis 10, which is inserted into the arc-shaped hole 241 and forms a sliding fit with it. The rotation center of the swing arm 251 is coaxially arranged with the center of the sector of the second gear 24. The first rotating shaft is inclined, the second transmission shaft 22 is vertically arranged, and the second gear 24 is installed below the chassis 10. This invention hides most of the transmission components below the chassis 10, simplifying the upper structure of the lawnmower, increasing the seating space, and improving the operator's comfort.

[0087] Please see Figure 6 , 8 As shown, in a specific embodiment, the second preset interval B includes a first sub-interval B1 and a second sub-interval B2 located at both ends of the first preset interval A; when the rotation angle of the first angle sensor 25 is located in the first sub-interval B1, the control module 60 controls the rotation speed of the drive wheel 12 on the left to be less than the rotation speed of the drive wheel 12 on the right; when the rotation angle of the first angle sensor 25 is located in the second sub-interval B2, the control module 60 controls the rotation speed of the drive wheel 12 on the right to be less than the rotation speed of the drive wheel 12 on the left.

[0088] The third preset interval C includes a third sub-interval C1 and a fourth sub-interval C2, which are located at opposite ends of the union formed by the first preset interval A and the second preset interval B. When the rotation angle of the first angle sensor 25 is located in the third sub-interval C1, the control module 60 controls the drive wheel 12 on the left to rotate in the opposite direction. When the rotation angle of the first angle sensor 25 is located in the fourth sub-interval C2, the control module 60 controls the drive wheel 12 on the right to rotate in the opposite direction.

[0089] Please see Figure 12 As shown, when the first angle sensor 25 changes within a certain angle range, the output voltage of the first angle sensor 25 changes with its rotation angle, thus making the angle-voltage relationship an increasing straight line. The first preset interval A of this invention should be taken from the middle section of this straight line. The second preset interval B should be a section extending from both ends of the first preset interval A, representing normal left turns and normal right turns, respectively. The third preset interval C should be the two end sections extending outward from the two sections of the second preset interval B, representing zero-radius left turns and zero-radius right turns, respectively. It is understood that...Figure 12 The 0 point position of the middle angle can be considered to be established, for example, the midpoint of the diagonal is taken as the 0 point in the embodiment, so that the direction of the turn is determined according to the positive and negative of the angle.

[0090] Please refer to Figure 3 , 5 , in a specific embodiment, the control device further comprises a throttle pedal 30 and a second angle sensor 33, specifically, the throttle pedal 30 is drivingly connected with the second angle sensor 33 through a connecting rod mechanism, and the second angle sensor 33 is electrically connected with the control module 60; the control module 60 is configured to increase the rotating speed of the driving wheel 12 when the rotating angle of the second angle sensor 33 increases.

[0091] Please refer to Figure 3 , 5 , in a specific embodiment, the throttle pedal 30 is fixedly connected with a horizontal rotating shaft 31, the horizontal rotating shaft 31 is rotatably connected with the chassis 10, the connecting rod mechanism comprises a first swing rod 311, a connecting rod 32 and a second swing rod 331, the first swing rod 311 is fixedly connected with the horizontal rotating shaft 31, the second swing rod 331 is connected with the second angle sensor 33, and the two ends of the connecting rod 32 are hingedly connected with the first swing rod 311 and the second swing rod 331 respectively; a cantilever 301 is arranged on the horizontal rotating shaft 31, a damper 34 is arranged between the cantilever 301 and the chassis 10, and the two ends of the damper 34 are hingedly connected with the cantilever 301 and the chassis 10 respectively; a mounting seat 13 is arranged on the chassis 10, and the second angle sensor 33 and the damper 34 are mounted on the mounting seat 13.

[0092] In a specific embodiment, the rotating speed of one of the driving wheels 12 is determined by the depth of the pedal of the throttle pedal 30, that is, the rotating speed of the driving wheel 12 located on the outer side during turning, and then the rotating speed of the other driving wheel 12 is adjusted according to the rotating state of the steering wheel 20 based on the rotating speed of the driving wheel 12, and the specific control method is as follows:

[0093] When the rotating angle of the first angle sensor 25 is in the first preset interval A, the rotating speed N L of the driving wheel 12 on the left side and the rotating speed N R of the driving wheel 12 on the right side satisfy:

[0094] N L =N R =(N max / (U max -U min ))*(U2-U min );

[0095] When the rotation angle of the first angle sensor 25 is in the first sub-interval B1, the rotational speed N L of the left drive wheel 12 and the rotational speed N R of the right drive wheel 12 satisfy:

[0096] N R = (N max / (U max -U min ))*(U2-U min ) ;

[0097] N L = ((U1-U a ) / (U b -U a ))*N R ;

[0098] When the rotation angle of the first angle sensor 25 is in the second sub-interval B2, the rotational speed N L of the left drive wheel 12 and the rotational speed N R of the right drive wheel 12 satisfy:

[0099] N L = (N max / (U max -U min ))*(U2-U min ) ;

[0100] N R = ((U d -U1) / (U d -U c ))*N L ;

[0101] When the rotation angle of the first angle sensor 25 is in the third sub-interval C1, the rotational speed N L of the left drive wheel 12 and the rotational speed N R of the right drive wheel 12 satisfy:

[0102] N R = (N max / (U max -U min ))*(U2-U min ) ;

[0103] N L = -((U f -U1) / (U f -U e ))*N R ;

[0104] When the rotation angle of the first angle sensor 25 is located in the fourth sub-interval C2, the rotation speed N L of the left drive wheel 12 R satisfies:

[0105] N L =(N max / (U max -U min ))*(U2-U min );

[0106] N R =-((U 1- U g ) / (U h -U g ))*N L ;

[0107] wherein N max represents the maximum rotation speed of the drive wheel 12, U max represents the maximum output voltage of the second angle sensor 33, U min represents the minimum output voltage of the second angle sensor 33, U2 represents the real-time output voltage of the second angle sensor 33; U a and U b respectively represent the minimum output voltage and the maximum output voltage of the first angle sensor 25 when the rotation angle of the first angle sensor 25 is located in the first sub-interval B1, and U1 represents the real-time output voltage of the first angle sensor 25; U c and U d respectively represent the minimum output voltage and the maximum output voltage of the first angle sensor 25 when the rotation angle of the first angle sensor 25 is located in the second sub-interval B2, U e and U f respectively represent the minimum output voltage and the maximum output voltage of the first angle sensor 25 when the rotation angle of the first angle sensor 25 is located in the third sub-interval C1, U g and U h respectively represent the minimum output voltage and the maximum output voltage of the first angle sensor 25 when the rotation angle of the first angle sensor 25 is located in the second sub-interval B2. Please refer to Figure 13 , 14 In a specific embodiment, the third sub-interval C1, the first sub-interval B1, the first preset interval A, the second sub-interval B2 and the fourth sub-interval C2 are sequentially adjacent, thus in the embodiment, U a =U f , Ud = U g .

[0108] It should be noted that the positive and negative of the rotating speed in the present application represent different rotating directions of the driving wheel 12, that is, the positive rotating speed represents the forward rotation of the driving wheel 12, and the negative rotating speed represents the backward rotation of the driving wheel 12.

[0109] Please refer to Figure 9 Based on the above control device, the present application further provides a garden tool control method, comprising the following steps:

[0110] S1: obtaining the detection signal of the first angle sensor 25;

[0111] controlling the rotating speed of the left driving wheel 12 and the right driving wheel 12 according to the detection signal, comprising:

[0112] S2: judging whether the rotating angle of the steering wheel 20 to the left or to the right is less than or equal to a first preset value, if yes, executing step S3, otherwise executing step S4;

[0113] S3: controlling the left driving wheel 12 and the right driving wheel 12 to rotate at the same speed;

[0114] S4: judging whether the steering wheel 20 rotates to the left, if yes, executing step S5, otherwise executing step S8;

[0115] S5: judging whether the rotating angle of the steering wheel 20 is less than or equal to a second preset value, if yes, executing step S6, otherwise executing step S7;

[0116] S6: controlling the rotating speed of the left driving wheel 12 to be lower than that of the right driving wheel 12;

[0117] S7: controlling the left driving wheel 12 to rotate backward;

[0118] S8: judging whether the rotating angle of the steering wheel 20 is less than or equal to a second preset value, if yes, executing step S9, otherwise executing step S10;

[0119] S9: controlling the rotating speed of the right driving wheel 12 to be lower than that of the left driving wheel 12;

[0120] S10: controlling the right driving wheel 12 to rotate backward.

[0121] The technical solutions of the present application will be described in detail below in combination with a specific embodiment:

[0122] The specifications of the angle sensor are as follows Figure 12As shown, the effective mechanical angle of the sensor is ±21°, totaling 42°, corresponding to an analog voltage output value of 0.3~4.5V. When the mechanical angle is 0°, the corresponding analog output value is 2.4V. In this embodiment, U a =U f =1.3V; U b =2.3V; U c =2.5V; U d =U g =3.5V; U e =0.3V; U h =4.5V.

[0123] An angle sensor is used for depth recognition of the accelerator pedal 30:

[0124] From the specifications of the angle sensor above, it can be seen that when the mechanical angle changes from -21° to +21°, the sensor's output voltage corresponds to 0.3V to 4.5V. Depending on the different mechanical structure designs, the actual mechanical angle range used by the sensor may vary. Here, we design it based on the maximum range, that is, from the accelerator pedal 30 being unpressed to being fully depressed, the mechanical angle of the angle sensor increases from -21° to +21°, and the output voltage increases from 0.3V to 4.5V. Assuming the user has no steering requirement, the driving direction is forward, and the maximum speed of the drive motor is 3000rpm, therefore, when the two motor drivers detect the voltage change of the accelerator pedal 30 sensor, the speed of the drive motor increases from 0rpm to the maximum speed of 3000rpm. The speed is directly proportional to the output voltage value of the accelerator pedal 30. That is:

[0125] N = 714 * U² - 214.2;

[0126] Where N is the motor speed (unit: rpm);

[0127] U is the output voltage value of the accelerator pedal 30 (unit: V);

[0128] Angle sensors are used for steering wheel angle recognition.

[0129] Since the steering wheel 20 has two rotation directions, left and right, the angle sensor should be in the initial installation position when the steering wheel 20 is in the middle position, that is, the detection angle of the angle sensor at this time should be 0°, and this position also corresponds to the initial position of the steering wheel 20. Different models and requirements, the steering wheel 20 may have different limit mechanical steering angles, since the steering wheel 20 and the angle sensor in the present application are two-stage transmission, so changing the transmission ratio can change the limit voltage output value of the angle sensor. Here, the angle of the sensor is described, and it is known that the maximum mechanical angle change of the sensor is 42°, in order to meet the requirements of normal driving and zero steering, the angle range needs to be divided as follows:

[0130] a, forward, area A, ±1°, 2.3-2.5V;

[0131] b, left ordinary turn, area B1, -1°-11°, 1.3-2.3V;

[0132] c, left zero steering turn, area C1, -11°-21°, 0.3-1.3V;

[0133] d, right ordinary turn, area B2, +1°-+11°, 2.5-3.5V;

[0134] e, right zero steering turn, area C2, +11°-+21°, 3.5-4.5V;

[0135] For example, in the forward direction:

[0136] a is used as a steering dead zone to prevent the steering from being too sensitive and exceeding the user's operation expectations, and is also used to reduce the deviation between different machines. When in this area, the rotation speeds of the left and right wheels are the same, and the direction is determined by the gear shift switch.

[0137] b is used for left turn, at this time the rotation directions of the two wheels are consistent, but as the angle of the steering wheel 20 deflects to the left increases, the rotation speed of the left wheel will be lower, until the steering reaches the junction of b and c, the rotation speed of the left wheel drops to 0 rpm.

[0138] c is used for left zero steering, at this time the rotation directions of the two wheels are inconsistent, and as the angle of the steering wheel 20 deflects to the left increases, the rotation speed of the left wheel will be higher, until the steering reaches the limit, the rotation speed of the left wheel reaches 3000 rpm in the negative direction, thereby achieving complete left zero steering.

[0139] d and b have the same mechanism, at this time the rotation directions of the two wheels are consistent, but as the angle of the steering wheel 20 deflects to the right increases, the rotation speed of the right wheel will be lower, until the steering reaches the junction of d and e, the rotation speed of the right wheel drops to 0 rpm.

[0140] e. The mechanism is consistent with c, at this time the rotation direction of the two wheels is inconsistent, and the greater the angle of the steering wheel 20 deflected to the right, the higher the speed of the right wheel will be, until the steering reaches the limit, the right wheel speed to the negative 3000 rpm, so as to achieve the right completely zero steering.

[0141] Taking the forward gear as an example, the driving speed calculation method of each region is as follows:

[0142] Wherein, NL and NR are the left and right motor speeds (unit: rpm);

[0143] U1 is the output voltage value of the steering wheel 20 (unit: V);

[0144] U2 is the output voltage value of the accelerator pedal 30 (unit: V);

[0145] I. Forward, U1∈(2.3, 2.5);

[0146] NL=NR=714*U2-214.2;

[0147] II. Left ordinary turn, U1∈(1.3, 2.3);

[0148] NL=(U1-1.3)*NR;

[0149] NR=714*U2-214.2;

[0150] III. Left zero steering turn, U1∈(0.3, 1.3);

[0151] NL=-(1.3-U1)*NR;

[0152] NR=714*U2-214.2;

[0153] IV. Right ordinary turn, U1∈(2.5, 3.5);

[0154] NL=714*U2-214.2;

[0155] NR=(3.5-U1)*NL;

[0156] V. Right zero steering turn, U1∈(3.5, 4.5);

[0157] NL=714*U2-214.2;

[0158] NR=-(U1-3.5)*NL.

[0159] In summary, the present application generates actual position signal indicating the position state of the steering wheel 20 in the vehicle control system by using at least one angle sensor, instead of the inferred or expected position of the steering wheel 20, so as to effectively improve the response speed and response accuracy; the present application uses the steering input device (such as the steering wheel 20) to input the operation intention of the operator, and detects the actual position of the steering input device by using an angle sensor, and generates a signal, which is processed by the control module 60 to control one or more drivable structures of the vehicle, so that the driving motor realizes the forward and reverse rotation of the left and right wheels through the gear box, and the universal wheel 11 changes the turning angle with the control of the left and right rear wheel speed and steering during steering; the present application avoids the problem that the sensor potential value is too sensitive due to the slight rotation of the steering wheel 20 and the air travel of the transmission structure, and ensures the smooth and stable operation of the machine during zero steering.

[0160] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought of the present application should be covered by the claims of the present application.

[0161] In the description herein, many specific details are provided, such as examples of components and / or methods, to provide a thorough understanding of embodiments of the present application. Those skilled in the art will recognize, however, that the embodiments of the present application can be practiced without one or more of the specific details, or with other devices, systems, assemblies, methods, components, materials, parts, and / or the like. In other instances, well-known structures, materials, or operations are not specifically shown or described in detail in order to avoid obscuring aspects of embodiments of the present application.

[0162] Reference throughout this specification to "an embodiment", "embodiment", or "specific embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application and is not necessarily included in all embodiments. Thus, the appearances of the phrase "in one embodiment", "in an embodiment", or "in specific embodiments" in various places in this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, or characteristics of any specific embodiment of the present application can be combined in any suitable manner in one or more other embodiments. It is understood that other variations and modifications of the applications described and illustrated herein can be made based on the teachings herein, and are therefore within the scope of the present application.

[0163] It should also be understood that one or more of the elements illustrated in the drawings / figures can also be implemented in a more separated or integrated manner, or even removed and provided as a stand-alone element as desired in various applications. Many aspects of the application will be described using terms commonly used in the art, and the normal meanings of the terms will be employed where they are used.

[0164] In addition, unless explicitly stated otherwise, any drawings shown in the Figures are intended to be exemplary of the subject matter rather than to limit the spirit or scope of the present application. Furthermore, unless specifically stated otherwise, the term "or" as used herein is generally intended to mean "and / or", that is, the term "or" as used herein is generally intended to mean either "and / or" unless explicitly stated otherwise. Combinations of components or steps will also be generally intended to encompass individual and / or double combinations of the components or steps, unless specifically stated otherwise.

[0165] As used in the description of the application and the accompanying claims, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. As used in the description of the application and the accompanying claims, the term "in" includes both "in" and "on" unless explicitly stated otherwise.

[0166] The above description of the illustrated embodiments of the application (including what is described in the abstract) is not intended to be exhaustive or to limit the application to the precise forms disclosed. While specific embodiments of, and examples for, the application are described herein for illustrative purposes, various equivalent modifications are possible within the spirit and scope of the application, as those skilled in the relevant art will recognize and appreciate. As indicated, these modifications can be made to the above-described embodiments and yet the application will remain within the scope of the application.

[0167] The systems and methods have been described generally at this stage for the purposes of promoting an understanding of the aspects of the application. Further, various specific details have been given in order to provide a thorough understanding. However, a person of ordinary skill in the relevant art will recognize and appreciate that the embodiments of the application can be practiced without one or more of the specific details, or with other devices, systems, assemblies, methods, components, materials, parts, and so forth. In other instances, well-known structures, materials, and / or operations have not been shown or described in detail in order to avoid obscuring aspects of the embodiments of the application.

[0168] Thus, although the present application has been described herein with respect to particular embodiments thereof, alterations, modifications and variations will occur to others skilled in the art upon the reading and understanding of the foregoing description. It is intended that the application be construed as including all such alterations, modifications and variations as fall within the scope of the appended claims. Accordingly, the application is not intended to be limited to the specific embodiments described in the specification illustrating one or more aspects of the application and as such, other embodiments of the application will be obvious to one skilled in the art from this disclosure. It is therefore intended that the application not be limited, to the extent that modifications and variations do not constitute departures from the spirit and essence of the application.

Claims

1. A garden tool, characterized in that The utility model relates to a kind of garden tools, including: Chassis, universal wheel and at least two drive wheels are installed in the chassis, one of the universal wheel and the drive wheel is located in the front of the chassis, the other is located in the rear of the chassis; Steering wheel; With the chassis rotation is connected; First angle sensor, the steering wheel is drivingly connected with the first angle sensor through a speed reduction transmission mechanism; Control module, the first angle sensor is electrically connected with the control module, and the control module is electrically connected with the driving element of two drive wheels respectively; The control module is configured to: When the rotation angle of the first angle sensor is located in the first preset interval, the control module controls two drive wheels to rotate at constant speed; When the rotation angle of the first angle sensor is located in the second preset interval, the control module controls two drive wheels to rotate at differential speed in the same direction; When the rotation angle of the first angle sensor is located in the third preset interval, the control module controls two drive wheels to rotate reversely; Wherein the second preset interval is distributed at both ends of the first preset interval, and the third preset interval is distributed at both ends of the union formed by the first preset interval and the second preset interval; Further comprising: Accelerator pedal; Second angle sensor, the accelerator pedal is drivingly connected with the second angle sensor through a connecting rod mechanism, and the second angle sensor is electrically connected with the control module; The control module is configured to increase the rotation speed of the drive wheel when the rotation angle of the second angle sensor increases; When the rotation angle of the first angle sensor is in the first preset interval, the rotation speed N L of the left drive wheel and the rotation speed N R of the right drive wheel satisfy: N L =N R =(N max / (U max -U min ))×(U2-U min ); wherein N max represents the maximum rotational speed of the driving wheel, U max represents the maximum output voltage of the second angle sensor, U min represents the minimum output voltage of the second angle sensor, U2 represents the real-time output voltage of the second angle sensor; the output voltage of the second angle sensor increases with the increase of the rotation angle of the second angle sensor.

2. The garden tool of claim 1, wherein, The speed reduction transmission mechanism comprises: First transmission shaft, fixedly connected with the steering wheel, and rotationally connected with the steering wheel support provided on the garden tool; Second transmission shaft, rotationally connected with the chassis of the garden tool, one end of the second transmission shaft is synchronously rotationally connected with the first transmission shaft through a universal joint, and the other end of the second transmission shaft is provided with a first gear; Second gear, rotationally connected with the chassis of the garden tool, the second gear is engaged with the first gear, and the diameter of the second gear is greater than that of the first gear; Swing arm, one end of the swing arm is connected with the first angle sensor, and the other end of the swing arm is connected with the second gear.

3. The garden tool of claim 1, wherein, The second preset interval includes a first subinterval and a second subinterval distributed at both ends of the first preset interval; When the rotation angle of the first angle sensor is located in the first subinterval, the control module controls the rotation speed of the left drive wheel to be less than that of the right drive wheel; When the rotation angle of the first angle sensor is located in the second subinterval, the control module controls the rotation speed of the right drive wheel to be less than that of the left drive wheel.

4. A garden tool according to claim 3, characterised in that The third preset interval includes a third subinterval and a fourth subinterval distributed at both ends of the union formed by the first preset interval and the second preset interval; When the rotation angle of the first angle sensor is located in the third subinterval, the control module controls the left drive wheel to rotate reversely. When the rotation angle of the first angle sensor is in the fourth sub-interval, the control module controls the right drive wheel to rotate reversely.

5. The garden tool of claim 1, wherein, The first preset interval is [-1°, +1°].

6. The garden tool of claim 3, wherein, The second preset interval is [-11°, -1°)∪(+1°, +11°], wherein the first sub-interval is [-11°, -1°), and the second sub-interval is (+1°, +11°].

7. The garden tool of claim 4, wherein, The third preset interval is [-21°, -11°)∪(+11°, +21°], wherein the third sub-interval is [-21°, -11°), and the fourth sub-interval is (+11°, +21°].

8. The garden tool of claim 3, wherein, When the rotation angle of the first angle sensor is in the first sub-interval, the rotation speed N L of the left drive wheel and the rotation speed N R of the right drive wheel satisfy: N R = (N max / (U max -U min )) x (U2-U min ); N L = ((U1-U a ) / (U b -U a )) x N R ; wherein N max represents the maximum rotational speed of the driving wheel, U max represents the maximum output voltage of the second angle sensor, U min represents the minimum output voltage of the second angle sensor, U2 represents the real-time output voltage of the second angle sensor, U a and U b respectively represent the minimum output voltage and the maximum output voltage of the first angle sensor when the rotational angle of the first angle sensor is located in the first sub-interval, and the U1 represents the real-time output voltage of the first angle sensor; the real-time output voltage U1 of the first angle sensor increases with the increase of the rotational angle of the first angle sensor, and the real-time output voltage U2 of the second angle sensor increases with the increase of the rotational angle of the second angle sensor.

9. The garden tool of claim 3, wherein, When the rotation angle of the first angle sensor is in the second sub-interval, the rotation speed N L of the left drive wheel and the rotation speed N R of the right drive wheel satisfy: N L = (N max / (U max -U min )) x (U2-U min ); N R = ((U d -U1) / (U d -U c )) x N L ; wherein N max represents the maximum rotational speed of the drive wheel, U max represents the maximum output voltage of the second angle sensor, U min represents the minimum output voltage of the second angle sensor, U2 represents the real-time output voltage of the second angle sensor, U c and U d respectively represent the minimum output voltage and the maximum output voltage of the first angle sensor when the rotational angle of the first angle sensor is located in the second sub-interval, and the U1 represents the real-time output voltage of the first angle sensor; the real-time output voltage U1 of the first angle sensor increases with the increase of the rotational angle of the first angle sensor, and the real-time output voltage U2 of the second angle sensor increases with the increase of the rotational angle of the second angle sensor.

10. The garden tool of claim 4, wherein, When the rotation angle of the first angle sensor is in the third sub-interval, the rotation speed N L of the left drive wheel and the rotation speed N R of the right drive wheel satisfy: N R =(N max / (U max -U min ))×(U2-U min ); N L = -((U f -U1) / (U f -U e )) x N R ; wherein N max represents the maximum rotational speed of the drive wheel, U max represents the maximum output voltage of the second angle sensor, U min represents the minimum output voltage of the second angle sensor, U2 represents the real-time output voltage of the second angle sensor, U e and U f respectively represent the minimum output voltage and the maximum output voltage of the first angle sensor when the rotational angle of the first angle sensor is located in the third sub-interval, and the U1 represents the real-time output voltage of the first angle sensor; the real-time output voltage U1 of the first angle sensor increases with the increase of the rotational angle of the first angle sensor, and the real-time output voltage U2 of the second angle sensor increases with the increase of the rotational angle of the second angle sensor.

11. The garden tool of claim 4, wherein, When the rotation angle of the first angle sensor is in the fourth sub-interval, the rotation speed N L of the left drive wheel and the rotation speed N R of the right drive wheel satisfy: N L = (N max / (U max - U min )) x (U2- U min ); N R = -((U 1- -U g ) / (U h -U g )) x N L ; wherein N max represents the maximum rotational speed of the drive wheel, U max represents the maximum output voltage of the second angle sensor, U min represents the minimum output voltage of the second angle sensor, U2 represents the real-time output voltage of the second angle sensor, U g and U h respectively represent the minimum output voltage and the maximum output voltage of the first angle sensor when the rotational angle of the first angle sensor is located in the fourth sub-interval, and U1 represents the real-time output voltage of the first angle sensor; the real-time output voltage U1 of the first angle sensor increases with the increase of the rotational angle of the first angle sensor, and the real-time output voltage U2 of the second angle sensor increases with the increase of the rotational angle of the second angle sensor.

12. A garden tool control method characterized by comprising: The garden tool comprises a first angle sensor for identifying the rotation of a steering wheel, the first angle sensor being electrically connected with a control module, the control module being electrically connected with a left drive wheel and a right drive wheel respectively; the garden tool further comprises a throttle pedal and a second angle sensor, the throttle pedal being in transmission connection with the second angle sensor through a connecting rod mechanism, the second angle sensor being electrically connected with the control module, and the output voltage of the second angle sensor increasing with the increase of the rotation angle of the second angle sensor; the method comprises the following steps: acquiring a detection signal of the first angle sensor; controlling the rotation speed of the left drive wheel and the right drive wheel according to the detection signal, comprising: when the rotation angle of the steering wheel to the left or to the right is less than or equal to a first preset value, controlling the left drive wheel and the right drive wheel to rotate at the same speed; when the steering wheel rotates to the left, and the rotation angle is greater than the first preset value and less than or equal to a second preset value, controlling the rotation speed of the left drive wheel to be lower than that of the right drive wheel; when the steering wheel rotates to the left, and the rotation angle is greater than the second preset value, controlling the left drive wheel to rotate reversely; when the steering wheel rotates to the right, and the rotation angle is greater than the first preset value and less than or equal to a second preset value, controlling the rotation speed of the right drive wheel to be lower than that of the left drive wheel; when the steering wheel rotates to the right, and the rotation angle is greater than the second preset value, controlling the right drive wheel to rotate reversely; the method further comprises the following steps: when the rotation angle of the second angle sensor increases, controlling the rotation speed of the drive wheel to increase. When the rotation angle of the first angle sensor is in a first preset interval, control the rotation speed N of the left drive wheel L and the rotation speed N of the right drive wheel R to satisfy: N L =N R =(N max / (U max -U min ))×(U2-U min ); where N max represents the maximum rotational speed of the drive wheel, U max represents the maximum output voltage of the second angle sensor, U min represents the minimum output voltage of the second angle sensor, U2 represents the real-time output voltage of the second angle sensor.

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