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EP-4389565-B1 - GARDEN TOOL AND METHOD FOR CONTROLLING GARDEN TOOL

EP4389565B1EP 4389565 B1EP4389565 B1EP 4389565B1EP-4389565-B1

Inventors

  • WANG, Chaoqun
  • WEI, Qunli
  • XU, Wenwei
  • FAN, JUN
  • ZHAO, PENG
  • XUE, Jiafu

Dates

Publication Date
20260513
Application Date
20231207

Claims (14)

  1. A garden tool, comprising: a chassis (10), which is installed with a universal wheel (11), a left driving wheel (12) and a right driving wheel (12), one of the universal wheel (11) and the driving wheel (12) being located at a front portion of the chassis (10) and the other at a rear portion of the chassis (10); a steering wheel (20), which is rotatably connected to the chassis (10); a first angle sensor (25) configured to identify rotation of the steering wheel (20) and connected to the steering wheel (20) through transmission via a deceleration transmission mechanism; and a control module (60), to which the first angle sensor (25) is electrically connected, and the control module (60) being respectively electrically connected to driving elements of the left driving wheel (12) and the right driving wheel (12), wherein the control module (60) is configured to: obtain a detection signal from the first angle sensor (25), control the rotational speed of the left driving wheel (12) and the right driving wheel (12) according to the detection signal, to rotate at equal speeds when a left or right rotational angle of the steering wheel (20) is less than or equal to a first preset value, wherein the first preset value does not include zero; to rotate the left driving wheel (12) at a lower speed than that of the right driving wheel (12) when the steering wheel (20) is turning to the left and the rotational angle of the first angle sensor (25) is larger than the first preset value and less than or equal to a second preset value, to rotate the left driving wheel (12) backwards when the steering wheel (20) is turning to the left and the rotational angle of the first angle sensor (25) is larger than the second preset value, to rotate the right driving wheel (12) at a lower speed than that of the left driving wheel (12) when the steering wheel (20) is turning to the right and the rotational angle of the first angle sensor (25) is larger than the first preset value and less than or equal to the second preset value, and to rotate the right driving wheel (12) backwards when the steering wheel (20) is turning to the right and the rotational angle of the first angle sensor (25) is larger than the second preset value, wherein, when a left or right rotational angle of the steering wheel (20) is less than or equal to the first preset value, the left driving wheel (12) and the right driving wheel (12) are configured to rotate at equal speeds in a same direction, wherein the first preset value does not include zero; when the left or right rotational angle of the steering wheel (20) is larger than the first preset value and less than or equal to the second preset value, the left driving wheel (12) and the right driving wheel (12) are configured to rotate at different speeds in the same direction and when the left or right rotational angle of the steering wheel (20) is larger than the second preset value, one of the left driving wheel (12) and the right driving wheel (12) is configured to rotate backwards and the other one is configured to rotate forwards, at equal speeds.
  2. The garden tool of claim 1, wherein the deceleration transmission mechanism comprises: a first transmission shaft (21), which is fixedly connected to the steering wheel (20) and rotatably connected to a steering wheel bracket provided on the garden tool; a second transmission shaft (22), which is rotatably connected to the chassis (10) of the garden tool, wherein a first end of the second transmission shaft (22) is connected to the first transmission shaft (21) via a universal joint in a synchronously rotating manner, and a second end of the second transmission shaft (22) is provided with a first gear (221); a second gear (24), which is rotatably connected to the chassis (10) of the garden tool and is meshed with the first gear (221), a diameter of the second gear (24) being greater than that of the first gear (221); and a swing arm (251), a first end of the swing arm (251) being connected to the first angle sensor(25), and a second end of the swing arm (251) being connected to the second gear (24).
  3. The garden tool of claim 1, wherein, when a left or right rotational angle of the steering wheel (20) is less than or equal to the first preset value, a rotational angle of the first angle sensor (25) is within a first preset interval (A) and when the left or right rotational angle of the steering wheel (20) is larger than the first preset value and less than or equal to the second preset value, the rotational angle of the first angle sensor (25) is within a second preset interval (B), the second preset interval (B) includes a first sub interval (B1) and a second sub interval (B2) provided at two ends of the first preset interval (A), respectively; when the rotational angle of the first angle sensor (25) is within the first sub interval (B1), the control module (60) is configured to control a rotational speed of the driving wheel (12) on a left side to be lower than that of the driving wheel (12) on a right side; and when the rotational angle of the first angle sensor (25) is within the second sub interval (B2), the control module (60) is configured to control the rotational speed of the driving wheel (12) on the right side to be lower than that of the driving wheel (12) on the left side.
  4. The garden tool of claim 3, wherein, when the left or right rotational angle of the steering wheel (20) is larger than the second preset value, the rotational angle of the first angle sensor (25) is within a third preset interval (C), the third preset interval (C) includes a third sub interval (C1) and a fourth sub interval (C2), the third sub interval (C1) and the fourth sub interval (C2) are provided at two ends of the union of the first preset interval (A) and the second preset interval (B), respectively; when the rotational angle of the first angle sensor (25) is within the third sub interval (C1), the control module (60) is configured to control the driving wheel (12) on the left side to rotate in an opposite direction; and when the rotational angle of the first angle sensor (25) is within the fourth sub interval (C2), the control module (60) is configured to control the driving wheel (12) on the right side to rotate in an opposite direction.
  5. The garden tool of claim 1, wherein the first preset interval (A) is [-1°, +1°].
  6. The garden tool of claim 3, wherein, the second preset interval (B) is [-11°, -1°) U (+1°, +11°], wherein the first sub interval (B1) is [-11°, -1°), and the second sub interval (B2) is (+1°, +11°].
  7. The garden tool of claim 4, wherein, the third preset interval (C) is [-21°, -11°) U (+11°, +21°], wherein the third sub interval (C1) is [-21°, -11°), and the fourth sub interval (C2) is (+11°, +21°].
  8. The garden tool of claim 4, wherein the garden tool further comprises a control device, the control device comprising: an accelerator pedal (30); and a second angle sensor (33), wherein the accelerator pedal (30) is connected to the second angle sensor (33) through transmission via a linkage mechanism, and the second angle sensor (33) is electrically connected to the control module (60), and wherein the control module (60) is configured to control a rotational speed of the driving wheel (12) to increase when a rotational angle of the second angle sensor (33) increases.
  9. The garden tool of claim 8, wherein, when the rotational angle of the first angle sensor (25) is within the first preset interval (A), the rotational speed N L of the driving wheel (12) on the left side and the rotational speed N R of the driving wheel (12) on the right side meet the following requirements: N L = N R = N max / U max − U min * U 2 − U min ; wherein, N max represents a maximum rotational speed of the driving wheel (12), U max represents a maximum output voltage of the second angle sensor (33), U min represents a minimum output voltage of the second angle sensor (33), and U 2 represents a real-time output voltage of the second angle sensor (33); and wherein an output voltage of the second angle sensor (33) increases with an increase of the rotational angle of the second angle sensor (33).
  10. The garden tool of claim 8, wherein, when the rotational angle of the first angle sensor (25) is within the first sub interval (B1), the rotational speed N L of the driving wheel (12) on the left side and the rotational speed N R of the driving wheel (12) on the right side meet the following requirements: N R = N max / U max − U min * U 2 − U min ; N L = U 1 − U a / U b − U a * N R ; wherein, N max represents a maximum rotational speed of the driving wheel (12), U max represents a maximum output voltage of the second angle sensor (33), U min represents a minimum output voltage of the second angle sensor (33), U 2 represents a real-time output voltage of the second angle sensor (33), U a and U b respectively represent a minimum output voltage and a maximum output voltage of the first angle sensor (25) when the rotational angle of the first angle sensor (25) is within the first sub interval (B1), and U 1 represents a real-time output voltage of the first angle sensor (25); and wherein the real-time output voltage U 1 of the first angle sensor (25) increases with an increase of the rotational angle of the first angle sensor (25), and the real-time output voltage U 2 of the second angle sensor (33) increases with an increase of the rotational angle of the second angle sensor (33).
  11. The garden tool of claim 8, wherein, when the rotational angle of the first angle sensor (25) is within the second sub interval (B2), the rotational speed N L of the driving wheel (12) on the left side and the rotational speed N R of the driving wheel (12) on the right side meet the following requirements: N L = N max / U max − U min * U 2 − U min ; N R = U d − U 1 / U d − U c * N L ; wherein, N max represents a maximum rotational speed of the driving wheel (12), U max represents a maximum output voltage of the second angle sensor (33), U min represents a minimum output voltage of the second angle sensor (33), U 2 represents a real-time output voltage of the second angle sensor (33), U c and U d respectively represent a minimum output voltage and a maximum output voltage of the first angle sensor (25) when the rotational angle of the first angle sensor (25) is within the second sub interval (B2), and U 1 represents a real-time output voltage of the first angle sensor (25); and wherein the real-time output voltage U 1 of the first angle sensor (25) increases with an increase of the rotational angle of the first angle sensor (25), and the real-time output voltage U 2 of the second angle sensor (33) increases with an increase of the rotational angle of the second angle sensor (33).
  12. The garden tool of claim 8, wherein, when the rotational angle of the first angle sensor (25) is within the third sub interval (C1), the rotational speed N L of the driving wheel (12) on the left side and the rotational speed N R of the driving wheel (12) on the right side meet the following requirements: N R = N max / U max − U min * U 2 − U min ; N L = − U f − U 1 / U f − U e * N R ; wherein, N max represents a maximum rotational speed of the driving wheel (12), U max represents a maximum output voltage of the second angle sensor (33), U min represents a minimum output voltage of the second angle sensor (33), U 2 represents a real-time output voltage of the second angle sensor (33), U e and U f respectively represent a minimum output voltage and a maximum output voltage of the first angle sensor (25) when the rotational angle of the first angle sensor (25) is within the third sub interval (C1), and U 1 represents a real-time output voltage of the first angle sensor (25); and wherein the real-time output voltage U 1 of the first angle sensor (25) increases with an increase of the rotational angle of the first angle sensor (25), and the real-time output voltage U 2 of the second angle sensor (33) increases with an increase of the rotational angle of the second angle sensor (33).
  13. The garden tool of claim 8, wherein, when the rotational angle of the first angle sensor (25) is within the fourth sub interval (C2), the rotational speed N L of the driving wheel (12) on the left side and the rotational speed N R of the driving wheel (12) on the right side meet the following requirements: N L = N max / U max − U min * U 2 − U min ; N R = − U 1 − U g / U h − U g * N L ; wherein, N max represents a maximum rotational speed of the driving wheel (12), U max represents a maximum output voltage of the second angle sensor (33), U min represents a minimum output voltage of the second angle sensor (33), U 2 represents a real-time output voltage of the second angle sensor (33), U g and U h respectively represent a minimum output voltage and a maximum output voltage of the first angle sensor (25) when the rotational angle of the first angle sensor (25) is within the fourth sub interval (C2), and U 1 represents a real-time output voltage of the first angle sensor (25); and wherein the real-time output voltage U 1 of the first angle sensor (25) increases with an increase of the rotational angle of the first angle sensor (25), and the real-time output voltage U 2 of the second angle sensor (33) increases with an increase of the rotational angle of the second angle sensor (33).
  14. A method for controlling a garden tool, wherein, the garden tool comprises a first angle sensor (25) configured to identify a rotation of a steering wheel (20), the first angle sensor (25) being electrically connected to a control module (60), the control module (60) being respectively electrically connected to a left driving wheel (12) and a right driving wheel (12), the method comprises: obtaining a detection signal of the first angle sensor (25); and controlling rotational speeds of the left driving wheel (12) and the right driving wheel (12) according to the detection signal, comprising: controlling the left driving wheel (12) and the right driving wheel (12) to rotate at equal speeds when a left or right rotational angle of the steering wheel (20) is less than or equal to a first preset value, wherein the first preset value does not include zero; controlling the rotational speed of the left driving wheel (12) to be lower than that of the right driving wheel (12) when the steering wheel (20) is turning to the left and the rotational angle is larger than the first preset value and less than or equal to a second preset value; controlling the left driving wheel (12) to rotate backwards when the steering wheel (20) is turning to the left and the rotational angle is larger than the second preset value; controlling the rotational speed of the right driving wheel (12) to be lower than that of the left driving wheel (12) when the steering wheel (20) is turning to the right and the rotational angle is larger than the first preset value and less than or equal to the second preset value; and controlling the right driving wheel (12) to rotate backwards when the steering wheel (20) is turning to the right and the rotational angle is larger than the second preset value, wherein, when a left or right rotational angle of the steering wheel (20) is less than or equal to the first preset value, the left driving wheel (12) and the right driving wheel (12) rotate at equal speeds in a same direction, wherein the first preset value does not include zero; when the left or right rotational angle of the steering wheel (20) is larger than the first preset value and less than or equal to the second preset value, the left driving wheel (12) and the right driving wheel (12) rotate at different speeds in the same direction; and when the left or right rotational angle of the steering wheel (20) is larger than the second preset value, one of the left driving wheel (12) and the right driving wheel (12) rotates backwards and the other one is rotates forwards, at equal speeds.

Description

Technical Field The present invention belongs to the field of garden tools, specifically to a garden tool and control method thereof. Background In order to ensure the flexibility of movement, garden tools such as mowers and snow throwers generally require the ability to achieve small radius steering operations, or even zero radius steering operations. In the related art, steering operations are generally achieved by controlling the deflection angle of the front wheels. With such a steering structure, when achieving zero radius steering, the transmission mechanism is relatively complex, and there is relative sliding friction between the rear wheels and the ground during the steering process, which may cause damage to the lawn. WO2013/163317 discloses a vehicle control systems that can be used, to make low- to substantially zero-radius turns. Some of the vehicle control systems utilize at least one steered wheel position sensor to generate a signal that indicates the actual position of the steerable structure, e.g., wheel to which the sensor is coupled, rather than a projected or anticipated position of that steerable structure. Summary In view of the drawbacks of the related art mentioned above, the present invention aims to provide a garden tool and control method thereof that can flexibly control the steering radius and has a simple structure. To achieve the above and other related purposes, the present invention provides a garden tool as defined by independent claim 1 and a method for controlling the garden tool as defined by claim 14. Preferred embodiments of the present invention are defined by the dependent claims 2 to 13. The technical effects of the present invention lie in: the present invention utilizes at least one angle sensor in the vehicle control system to generate an actual position signal indicating the position status of the steering wheel, rather than an inferred or expected position of the steering wheel, thus effectively improving response speed and response accuracy; the present invention utilizes a steering input device (such as a steering wheel) to input the operator's operating intention, and detects the actual position of the steering input device through an angle sensor to generate a signal, this signal is processed by a control module to control one or more drivable structures of the vehicle, enabling the driving motor to achieve forward and reverse rotation of the left and right wheels via a gearbox, when steering, the universal wheel change the turning angle with the control of the rotational speeds and steering for the left and right rear wheels; the present invention avoids the problem of excessive sensitivity of sensor potential changes caused by slight rotation of the steering wheel and some idle stroke on the transmission structure through deceleration transmission, ensuring smooth and stable machine operation during zero steering. Brief Description Of Drawings Fig. 1 is a perspective view of the mower provided by an embodiment of the present invention;Fig. 2 is a top view of the mower provided by an embodiment of the present invention;Fig. 3 is a transmission structure diagram of the control device provided in an embodiment of the present invention;Fig. 4 is a perspective view of the deceleration transmission mechanism provided by an embodiment of the present invention;Fig. 5 is a perspective view of the linkage transmission mechanism provided in the embodiment of the present invention;Fig. 6 is a control schematic diagram of the mower provided in an embodiment of the present invention in a straight ahead state;Fig. 7 is a control schematic diagram of the mower provided in an embodiment of the present invention in a left normal steering state;Fig. 8 is a control schematic diagram of the mower provided in an embodiment of the present invention in a left zero radius steering state;Fig. 9 is a flowchart of the steering control method for the mower provided in an embodiment of the present invention;Fig. 10 is a schematic diagram of the mower provided in an embodiment of the present invention when steering normally;Fig. 11 is a schematic diagram of the mower provided in an embodiment of the present invention when zero radius steering;Fig. 12 is a curve of the voltage of the angle sensor provided by an embodiment of the present invention as a function of the angle;Fig. 13 is a schematic diagram of the angle sensor provided in an embodiment of the present invention divided into intervals; andFig. 14 is a schematic diagram of the relationship between voltage and angle provided by an embodiment of the present invention. Description Of Embodiments The following are specific examples to illustrate the embodiments of the present invention, and those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed herein. It should be noted that the illustrations provided in the following embodiments only illustrate the basi