An omnidirectional forklift steering wheel mechanism and control method thereof

Abstract

The present invention discloses an omnidirectional forklift steering wheel mechanism and a control method thereof, comprising a large gear mounted on a base, a small gear meshing with the large gear, a driving device connected to the small gear to control the rotation of the small gear, a steering wheel assembly connected to the large gear, a first angle sensor for detecting the rotation angle of the driving device, a second angle sensor for detecting the rotation angle of the steering wheel assembly, and a steering controller connected to both the first angle sensor and the second angle sensor for changing the rotation angle of the driving device to make the theoretical value equal to the first actual value and / or the second actual value when the theoretical value of driving the steering wheel assembly to rotate is not equal to the first actual value detected by the first angle sensor and / or the second actual value detected by the second angle sensor. The omnidirectional forklift steering wheel mechanism and the control method thereof realize redundant control of steering, thereby enabling the vehicle to freely travel in a narrow passage.

Description

Technical Field

[0001] The present invention relates to the technical field of forklifts, and in particular to an omnidirectional forklift steering wheel mechanism and a control method thereof. Background Art

[0002] The front steering wheel steering mechanism of the full-forward-moving forklift adopts a horizontal bevel gear reduction box, a transmission chain is movably arranged at the output end of the horizontal bevel gear reduction box, a front steering wheel fixing device is movably arranged in the transmission chain, a front steering wheel is fixedly arranged on the front steering wheel fixing device, and a steering motor, a horizontal bevel gear reduction box, a transmission chain, a photoelectric switch, a front steering wheel fixing device, a steering controller and a planetary reduction box are all arranged in the inner cavity of the vehicle body leg.

[0003] However, the existing technology uses chain transmission, which has low transmission accuracy and poor reliability. The speed reduction mechanism is scattered, occupies a large space, and has a non-compact structure, resulting in high leg height and wide width. The steering control method is open-loop, with poor control accuracy, which easily causes problems such as vehicle deviation and wheel wear.

[0004] In summary, how to effectively solve the problem of being unable to control the wheels to move freely in a narrow passage is a problem that those skilled in the art urgently need to solve. Summary of the invention

[0005] An object of the present invention is to provide an omnidirectional forklift steering wheel mechanism, which realizes redundant control of steering, thereby allowing the vehicle to travel freely in a narrow passage; another object of the present invention is to provide a control method based on the above-mentioned omnidirectional forklift steering wheel mechanism, and its beneficial effects are the same as those of the omnidirectional forklift steering wheel mechanism.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A steering wheel mechanism for an omnidirectional forklift, comprising a large gear mounted on a base, a small gear meshing with the large gear, a driving device connected to the small gear for controlling the rotation of the small gear, a steering wheel assembly connected to the large gear, a first angle sensor for detecting the rotation angle of the driving device, a second angle sensor for detecting the rotation angle of the steering wheel assembly, and a steering controller connected to both the first angle sensor and the second angle sensor for changing the rotation angle of the driving device so that the theoretical value is equal to the first actual value and / or the second actual value when a theoretical value for driving the steering wheel assembly to rotate is not equal to a first actual value detected by the first angle sensor and / or a second actual value detected by the second angle sensor.

[0008] Optionally, the large gear and the small gear are meshed and connected via a transition gear, the transition gear is connected to the base via a transition gear shaft, and the second angle sensor is specifically an absolute angle sensor connected to the lower end of the transition gear shaft.

[0009] Optionally, a swing arm with a long hole is connected to the lower end slot of the transition gear shaft, the eccentric shaft of the absolute angle sensor is connected to the eccentric hole of the coupling, the connecting shaft of the coupling is connected to the long hole, and the connecting shaft moves along the long hole.

[0010] Optionally, the driving device includes a steering motor and an L-shaped planetary reduction gearbox connected to the steering motor, and the first angle sensor is specifically a counting angle sensor connected to the steering motor.

[0011] Optionally, it also includes a zero position detection device for detecting whether the steering wheel assembly is in a zero position, the zero position detection device is connected to the steering controller, and the steering controller is used to control the steering wheel assembly to return to zero position when the steering wheel assembly is not in the zero position.

[0012] Optionally, the zero position detection device includes a detection strip provided on the steering wheel assembly and having a detection notch, and a zero position sensor located below the detection strip, the zero position sensor is located on the rotation radius of the detection notch, and the zero position sensor is connected to the steering controller.

[0013] Optionally, the steering wheel assembly is provided with a stepped shaft, the large gear and the inner ring of the slewing bearing are connected to the stepped shaft, the bottom surface of the base has a stepped hole, the outer ring of the slewing bearing is connected to the stepped hole, and the steering wheel assembly can rotate 360°.

[0014] Optionally, the base includes a high seat and a low seat connected to a side of the high seat, the high seat and the low seat form a height difference, the high seat and the low seat have a connecting hole on the connecting side, the large gear is connected to the bottom of the high seat, the transition gear and the small gear are connected to the top of the low seat, and the large gear and the transition gear are meshed at the connecting hole;

[0015] The connection holes on the low seat and the high seat are processed after being welded.

[0016] The present invention provides a control method for the omnidirectional forklift steering wheel mechanism based on any one of the above items, comprising the steps of:

[0017] Sending a theoretical value for driving the steering wheel assembly to rotate to a steering controller;

[0018] Detecting the rotation angle of the steering wheel assembly and / or the rotation angle of the driving device, and feeding back the measured first actual value and / or second actual value to the steering controller;

[0019] Determine whether the theoretical value is equal to the first actual value and / or the second actual value. If they are equal, maintain the rotation state of the drive device. If the values ​​are not equal, change the rotation angle of the drive device to make the theoretical value equal to the first actual value and / or the second actual value.

[0020] Optionally, the detecting the rotation angle of the steering wheel assembly and / or the rotation angle of the driving device includes:

[0021] Determine whether the first angle sensor and the second angle sensor are working normally. If the first angle sensor is working normally, use the first angle sensor to detect the turning angle of the steering wheel assembly; if the first angle sensor is not working normally, use the second angle sensor to detect the turning angle of the driving device.

[0022] The omnidirectional forklift steering wheel mechanism provided by the present invention has mounting positions for a large gear and a small gear on the base, the large gear and the small gear are mounted on the base, the small gear meshes with the large gear, the driving device is connected to the small gear, the driving device provides power to control the rotation of the small gear, and thus the rotation of the large gear is realized. The steering wheel assembly is connected to the large gear, and thus the steering wheel assembly is rotated.

[0023] The first angle sensor is used to detect the rotation angle of the driving device, and the second angle sensor is used to detect the rotation angle of the steering wheel assembly. The steering controller is connected to both the first angle sensor and the second angle sensor. The first angle sensor and the second angle sensor send the detected first actual value and / or second actual value to the steering controller. The steering controller performs calculations to convert the first actual value and / or the second actual value into a voltage value, and compares it with the theoretical voltage value input by the steering encoder. When the theoretical value of driving the steering wheel assembly to rotate is equal to the first actual value detected by the first angle sensor and / or the second actual value detected by the second angle sensor, the state of the driving device is maintained; when the theoretical value of driving the steering wheel assembly to rotate is not equal to the first actual value detected by the first angle sensor and / or the second actual value detected by the second angle sensor, the rotation angle of the driving device is changed to make the theoretical value equal to the first actual value and / or the second actual value.

[0024] The omnidirectional forklift steering wheel mechanism provided by the present invention realizes closed-loop detection and redundant detection of multiple signals. The theoretical value is compared with the second actual value detected by the second angle sensor to form a closed-loop detection, and the theoretical value is compared with the first actual value detected by the first angle sensor to form a redundant detection. Compared with the single closed-loop detection in the prior art, the redundant detection is safer and more reliable. When one of the angle sensors is damaged, the other angle sensor can still work, and the vehicle can work normally without stopping.

[0025] The present invention also provides a control method for the omnidirectional forklift steering wheel mechanism based on any one of the above items. Since the above-mentioned omnidirectional forklift steering wheel mechanism has the above-mentioned technical effects, the control method for the omnidirectional forklift steering wheel mechanism based on any one of the above items should also have corresponding technical effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] FIG1 is a schematic structural diagram of an omnidirectional forklift steering wheel mechanism provided in a specific embodiment of the present invention;

[0028] FIG2 is another view of the steering wheel mechanism of the omnidirectional forklift;

[0029] FIG3 is an exploded view of the steering wheel mechanism of an omnidirectional forklift;

[0030] FIG4 is a front view of the steering wheel mechanism of an omnidirectional forklift;

[0031] FIG5 is an enlarged view of point A in FIG2;

[0032] FIG6 is a schematic diagram of the connection between the absolute angle sensor and the second bracket;

[0033] FIG7 is a schematic structural diagram of a second bracket;

[0034] FIG8 is a schematic diagram showing the connection between the absolute angle sensor and the swing arm;

[0035] FIG9 is a schematic structural diagram of a base;

[0036] FIG10 is a schematic structural diagram of a steering wheel assembly;

[0037] FIG11 is a schematic diagram of the structure of a transition gear shaft;

[0038] FIG12 is a schematic diagram of the structure of a test strip;

[0039] 13 is a flow chart of a control method for an omnidirectional forklift steering wheel mechanism;

[0040] FIG. 14 is a control logic diagram of the steering wheel mechanism of an omnidirectional forklift.

[0041] Reference numerals:

[0042] Steering wheel assembly 1, first bracket 2, zero position sensor 3, large gear 4, slewing bearing 5, base 6, first washer 7, bolt 8, second washer 9, elastic retaining ring for hole 10, transition gear shaft 11, transition gear 12, bearing 13, intermediate retaining ring 14, elastic retaining ring for shaft 15, swing arm 16, coupling 17, absolute angle sensor 18, second bracket 19, pinion 20, L-type planetary reduction box 21, detection strip 22, detection notch 23, steering motor 24, counting angle sensor 25, step hole 61, step shaft 1-1, step surface 111, keyway 112, retaining ring groove 113, avoidance groove 161, and offset hole 171. DETAILED DESCRIPTION

[0043] The core of the present invention is to provide an omnidirectional forklift steering wheel mechanism, which realizes redundant control of steering, so that the vehicle can travel freely in narrow passages; another core of the present invention is to provide a control method based on the above-mentioned omnidirectional forklift steering wheel mechanism, and its beneficial effects are the same as those of the omnidirectional forklift steering wheel mechanism.

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] In a specific embodiment, the omnidirectional forklift steering wheel mechanism provided by the present invention has a specific structure with reference to Figures 1 to 12, including a large gear 4 installed on a base 6, a small gear 20 meshing with the large gear 4, a driving device connected to the small gear 20 for controlling the rotation of the small gear 20, a steering wheel assembly 1 connected to the large gear 4, a first angle sensor for detecting the rotation angle of the driving device, a second angle sensor for detecting the rotation angle of the steering wheel assembly 1, and a steering controller connected to both the first angle sensor and the second angle sensor for changing the rotation angle of the driving device so that the theoretical value is equal to the first actual value and / or the second actual value when the theoretical value of driving the steering wheel assembly 1 to rotate is not equal to the first actual value detected by the first angle sensor and / or the second actual value detected by the second angle sensor.

[0046] In the above structure, the steering wheel mechanism of the omnidirectional forklift includes a base 6, a large gear 4, a small gear 20, a driving device, a first angle sensor, a second angle sensor and a steering controller. The base 6 is provided with mounting positions for the large gear 4 and the small gear 20. The large gear 4 and the small gear 20 are mounted on the base 6. The small gear 20 meshes with the large gear 4. The driving device is connected to the small gear 20. The driving device provides power to control the rotation of the small gear 20, that is, to realize the rotation of the large gear 4. The steering wheel assembly 1 is connected to the large gear 4, that is, to realize the rotation of the steering wheel assembly 1. The transmission mechanism adopts gear transmission, which has high transmission accuracy and high reliability.

[0047] The theoretical value of driving the steering wheel assembly 1 to rotate means that when the driver turns the steering wheel, the steering wheel is mechanically connected to the steering encoder disk, and the steering wheel rotation angle can be converted into a voltage signal to output to the steering controller. This voltage value is the theoretical value.

[0048] The first angle sensor is used to detect the rotation angle of the driving device, and the second angle sensor is used to detect the rotation angle of the steering wheel assembly 1. The steering controller is connected to both the first angle sensor and the second angle sensor. The first angle sensor and the second angle sensor send the detected first actual value and / or second actual value to the steering controller. The steering controller performs calculations to convert the first actual value and / or the second actual value into a voltage value, and compares it with the theoretical voltage value input by the steering encoder disk.

[0049] When the theoretical value of the steering wheel assembly 1 driven to rotate is equal to the first actual value detected by the first angle sensor and / or the second actual value detected by the second angle sensor, the state of the driving device is maintained; when the theoretical value of the steering wheel assembly 1 driven to rotate is not equal to the first actual value detected by the first angle sensor and / or the second actual value detected by the second angle sensor, the rotation angle of the driving device is changed to make the theoretical value equal to the first actual value and / or the second actual value.

[0050] The omnidirectional forklift steering wheel mechanism provided by the present invention realizes closed-loop detection and redundant detection of multiple signals. The theoretical value is compared with the second actual value detected by the second angle sensor to form a closed-loop detection, and the theoretical value is compared with the first actual value detected by the first angle sensor to form a redundant detection. Compared with the single closed-loop detection in the prior art, the redundant detection is safer and more reliable. When one of the angle sensors is damaged, the other angle sensor can still work, and the vehicle can work normally without stopping.

[0051] It should be noted that closed-loop detection and redundant detection can be controlled simultaneously, with high control accuracy, high reliability and safety. Of course, only redundant detection or closed-loop detection can be performed. Since the first angle sensor directly detects the steering angle value of the steering wheel assembly 1, when the first angle sensor and the second angle sensor are working normally, the value detected by the first angle sensor is used for comparison, and the detection value is more accurate. When one of the two angle sensors fails, the value detected by the remaining angle sensor is used for comparison to ensure that the vehicle can work normally and does not shut down.

[0052] Based on the above-mentioned specific embodiments, the large gear 4 and the small gear 20 are meshed and connected through the transition gear 12, and the transition gear 12 is connected to the base 6 through the transition gear shaft 11. The second angle sensor is specifically an absolute angle sensor 18 connected to the lower end of the transition gear shaft 11.

[0053] In a specific embodiment, the base 6 is provided with installation positions for the large gear 4, the transition gear 12, and the small gear 20, and the transition gear shaft 11 is provided with a step surface 111, a keyway 112, and a retaining ring groove 113. The transition gear 12 is inserted into the transition gear shaft 11 and abuts against the step surface 111. The transition gear 12 is connected to the transition gear shaft 11 through the keyway 112. The bearing 13, the intermediate retaining ring 14, the bearing 13, and the shaft elastic retaining ring 15 are sequentially installed under the transition gear 12. At this time, the transition gear 12 is fixed on the transition gear shaft 11. Then the transition gear shaft 11 is downwardly installed into the step hole on the base 6, and the rear hole is connected to the retaining ring groove 113 with an elastic retaining ring 10 for axial positioning. The transition gear 12 can no longer move downward. At this time, the second washer 9 is used, and the bolt 8 is screwed into the threaded hole at the top of the transition gear shaft 11, and the transition gear 12 can only rotate.

[0054] In the above embodiment, a transition gear 12 is cleverly set between the large gear 4 and the small gear 20 to obtain the maximum transmission ratio in a limited space, that is, at the same transmission ratio, the size of the large gear 4 can be reduced to reduce the minimum required width of the side forklift for forking goods.

[0055] At the same time, since the large gear 4 and the small gear 20 themselves cannot be equipped with an angle sensor, a second angle sensor is connected to the lower end of the transition gear shaft 11, and the angle of the steering wheel assembly 1 is obtained by detecting the angle of the transition gear 12. Without increasing the height of the side forklift leg, the angle value of the steering wheel assembly 1 can be directly detected, and the detection value is more accurate, reliable and safe.

[0056] The absolute angle sensor 18 has a zero position itself, and outputs an absolute angle signal, but the detectable rotation angle is limited. A calibration process with an accuracy of 0.1° is provided to achieve high-precision angle measurement.

[0057] Based on the above-mentioned specific embodiments, a swing arm 16 with a long hole is connected to the lower end groove of the transition gear shaft 11, the eccentric shaft of the absolute angle sensor 18 is connected to the eccentric hole 171 of the coupling 17, and the connecting shaft of the coupling 17 is connected to the long hole, and the connecting shaft moves along the long hole.

[0058] In a specific embodiment, the absolute angle sensor 18 is mounted on the base 6 through the second bracket 19 and is located at the bottom of the transition gear 12. The second bracket 19 is mounted on the frame. The coupling 17 is provided with a skew hole 171. After the skew shaft on the absolute angle sensor 18 is inserted, it can rotate together with the absolute angle sensor 18. After the swing arm 16 is inserted into the notch at the bottom of the transition gear shaft 11 and fixed with a screw, the swing arm 16 can rotate together with the transition gear shaft 11. Finally, the connecting shaft of the coupling 17 and the long strip hole of the swing arm 16 are connected. At this time, the absolute angle sensor 18 can obtain the rotation angle data of the transition gear 12. Preferably, the bottom surface of the swing arm 16 is provided with an avoidance groove 161, and the connecting bolts of the swing arm 16 and the transition gear shaft 11 are connected at the avoidance groove 161, which does not affect the connection between the swing arm 16 and the coupling 17.

[0059] In the above embodiment, the connecting parts and the connecting method between the absolute angle sensor 18 and the transition gear shaft 11 are simple, the error is small, and the absolute angle sensor 18 can accurately detect the rotation angle data of the transition gear shaft 11.

[0060] On the basis of the above-mentioned specific embodiments, the driving device includes a steering motor 24 and an L-shaped planetary reduction box 21 connected to the steering motor 24 , and the first angle sensor is specifically a counting angle sensor 25 connected to the steering motor 24 .

[0061] In a specific embodiment, a boss is provided on the mounting surface of the L-type planetary reduction box 21, which is inserted into the mounting hole on the base 6, and then the L-type planetary reduction box 21 is fixed with a first washer 7 and a bolt 8. A keyway is provided on the pinion 20, which is inserted into the shaft at the top of the L-type planetary reduction box 21, and then screwed in and fixed with a second washer 9 and a bolt 8.

[0062] The first angle sensor is a counting angle sensor 25, which obtains an angle signal by counting the change in the zero position signal. It has no limit on the number of rotations and can detect a large rotation angle.

[0063] In the above embodiment, the speed reduction mechanism is L-shaped, occupies a small space, has a compact structure, and effectively reduces the height of the vehicle's legs. Without increasing the height of the side forklift's legs, the omnidirectional steering wheel drive mechanism is arranged.

[0064] Furthermore, when there is a reduction mechanism, when the steering wheel assembly 1 rotates one circle and the steering motor 24 rotates a large number of circles, the rotation angle of the steering wheel assembly 1 and the steering motor 24 can be obtained by detecting the rotation angle of the transition gear shaft 11 through the absolute angle sensor 18.

[0065] On the basis of the above-mentioned specific embodiments, it also includes a zero position detection device for detecting whether the steering wheel assembly 1 is in the zero position. The zero position detection device is connected to the steering controller. The steering controller is used to control the steering wheel assembly 1 to return to zero when the steering wheel assembly 1 is not in the zero position, thereby ensuring that the starting position of the steering wheel assembly 1 is in the zero position. Each steering starts from the zero position, thereby ensuring the correctness of the steering detection and steering.

[0066] Based on the above-mentioned specific embodiments, the zero position detection device includes a detection strip 22 provided on the steering wheel assembly 1 and having a detection notch 23, and a zero position sensor 3 located below the detection strip 22, the zero position sensor 3 is located on the rotation radius of the detection notch 23, and the zero position sensor 3 is connected to the steering controller.

[0067] In a specific embodiment, a detection strip 22 is installed on the steering wheel assembly 1, and two relative detection notches 23 are provided on the detection strip 22. The zero position sensor 3 is fixed to the vehicle frame through the first bracket 2, and the zero position sensor 3 is located in the zero position direction. The detection strip 22 stops rotating along with the steering wheel assembly 1. When the detection notch 23 is located directly above the zero position sensor 3, the zero position sensor 3 detects the detection notch 23 and determines that the steering wheel assembly 1 is in the zero position; when the detection notch 23 is not located directly above the zero position sensor 3, that is, the detection notch 23 and the zero position sensor 3 are offset in the vertical direction, the zero position sensor 3 does not detect the detection notch 23, determines that the steering wheel assembly 1 is not in the zero position, and controls the steering wheel assembly 1 to return to zero. The zero position detection device has a simple structure, a simple detection process, and reliable detection results.

[0068] On the basis of the above-mentioned specific embodiments, a step shaft 1-1 is provided on the steering wheel assembly 1, the large gear 4 and the inner ring of the slewing bearing 5 are connected to the step shaft 1-1, the bottom surface of the base 6 has a step hole 61, the outer ring of the slewing bearing 5 is connected to the step hole 61, and the steering wheel assembly 1 can rotate 360°.

[0069] In a specific embodiment, the base 6 is provided with a stepped hole 61 for the large gear 4, and the outer ring of the slewing bearing 5 is fixed to the base 6 by bolts 8 and first washers 7, and the inner ring passes through the large gear 4 and is fixed to the steering wheel assembly 1. Both the base 6 and the steering wheel assembly 1 are provided with steps for positioning the slewing bearing 5 and the large gear 4, and for bearing radial forces to prevent the bolts 8 from breaking.

[0070] Each wheel can rotate 360°, and the vehicle can control the turning angle of each wheel in real time, thereby realizing a variety of steering modes, such as straight driving, side driving, diagonal driving, right-angle turning, 360° rotation on the spot, etc., so that the vehicle can drive freely in narrow passages; allowing the side forklift to achieve no turning in the aisle, reducing collisions with equipment and shelves, and seamlessly switching between the main aisle and the shelf aisle, improving efficiency and safety.

[0071] On the basis of the above-mentioned specific embodiments, the base 6 includes a high seat and a low seat connected to the side of the high seat, the high seat and the low seat form a height difference, the high seat and the low seat have a connecting hole on the connecting side, the large gear 4 is connected to the bottom of the high seat, the transition gear 12 and the small gear 20 are connected to the top of the low seat, and the large gear 4 and the transition gear 12 are meshed at the connecting hole.

[0072] In a specific embodiment, the high seat and the low seat of the base 6 have a height difference, and the large gear 4 and the transition gear 12 are meshed at the side connecting hole of the height difference, ensuring the compact connection between the large gear 4 and the transition gear 12 and reducing the height and width of the support legs.

[0073] At the same time, the thickness of the high seat is less than that of the low seat, and the high seat is thinner, which can further reduce the height of the legs. The low seat is relatively thicker, meeting the load-bearing requirements of the L-type planetary reduction box 21, the steering motor 24, the transition gear 12, the pinion 20 and other components.

[0074] On the basis of the above-mentioned specific embodiments, the connection holes on the low seat and the high seat are processed after being welded together. In other words, the connection holes are processed after the low seat and the high seat are welded together, so as to reduce the influence of welding on the accuracy of the connection holes and ensure the accuracy requirements of assembly of various components.

[0075] In one embodiment, as shown in FIG. 13 and FIG. 14 , the present invention further provides a control method of the omnidirectional forklift steering wheel mechanism based on any one of the above items, which may include the following steps:

[0076] S110, sending a theoretical value for driving the steering wheel assembly 1 to rotate to the steering controller;

[0077] S120, detecting the turning angle of the steering wheel assembly 1 and / or the turning angle of the driving device, and feeding back the measured first actual value and / or the second actual value to the steering controller;

[0078] S130, determine whether the theoretical value is equal to the first actual value and / or the second actual value. If they are equal, maintain the rotation state of the driving device. If the values ​​are not equal, change the rotation angle of the driving device to make the theoretical value equal to the first actual value and / or the second actual value.

[0079] For the convenience of description, the above steps are combined for explanation below.

[0080] The first angle sensor is used to detect the rotation angle of the driving device, and the second angle sensor is used to detect the rotation angle of the steering wheel assembly 1. The steering controller is connected to both the first angle sensor and the second angle sensor. The first angle sensor and the second angle sensor send the detected first actual value and / or second actual value to the steering controller. The steering controller performs calculations to convert the first actual value and / or the second actual value into a voltage value, and compares it with the theoretical voltage value input by the steering encoder disk.

[0081] When the theoretical value of the steering wheel assembly 1 driven to rotate is equal to the first actual value detected by the first angle sensor and / or the second actual value detected by the second angle sensor, the state of the driving device is maintained; when the theoretical value of the steering wheel assembly 1 driven to rotate is not equal to the first actual value detected by the first angle sensor and / or the second actual value detected by the second angle sensor, the rotation angle of the driving device is changed to make the theoretical value equal to the first actual value and / or the second actual value.

[0082] By applying the technical solution provided in the embodiment of the present invention, closed-loop detection and redundant detection of multiple signals are realized. The theoretical value is compared with the second actual value detected by the second angle sensor to form a closed-loop detection, and the theoretical value is compared with the first actual value detected by the first angle sensor to form a redundant detection. Compared with the single closed-loop detection in the prior art, the redundant detection is safer and more reliable. When one of the angle sensors is damaged, the other angle sensor can still work, and the vehicle can work normally without stopping.

[0083] Based on the above specific embodiments, detecting the rotation angle of the steering wheel assembly 1 and / or the rotation angle of the driving device may include the following steps:

[0084] It is determined whether the first angle sensor and the second angle sensor are working normally. If the first angle sensor is working normally, the first angle sensor is used to detect the turning angle of the steering wheel assembly 1; if the first angle sensor is not working normally, the second angle sensor is used to detect the turning angle of the driving device.

[0085] In practical applications, closed-loop detection and redundant detection can be controlled simultaneously, with high control accuracy, reliability and safety. Of course, only redundant detection or closed-loop detection can be performed. Since the first angle sensor directly detects the steering angle value of the steering wheel assembly 1, when the first angle sensor and the second angle sensor are both working normally, the value detected by the first angle sensor is used for comparison, and the detection value is more accurate. When one of the two angle sensors fails, the value detected by the remaining angle sensor is used for comparison to ensure that the vehicle can work normally and does not shut down.

[0086] On the basis of the above-mentioned specific embodiments, before sending the theoretical value for driving the steering wheel assembly 1 to rotate to the steering controller, the following steps may also be included:

[0087] Check whether the steering wheel assembly 1 is in zero position. If yes, proceed to the next step. If not, control the steering wheel position to zero.

[0088] In the above embodiment, it can be ensured that the starting position of the steering wheel assembly 1 is at zero position, and each steering starts from zero position, thereby ensuring the correctness of steering detection and steering.

[0089] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0090] The omnidirectional forklift steering wheel mechanism and control method thereof provided by the present invention are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. Therefore, the present invention will not be limited to the embodiments shown in this article, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An omnidirectional forklift steering wheel mechanism, characterized in that: The invention comprises a large gear (4) mounted on a base (6), a small gear (20) meshing with the large gear (4), a driving device connected to the small gear (20) for controlling the rotation of the small gear (20), a steering wheel assembly (1) connected to the large gear (4), a first angle sensor for detecting the rotation angle of the driving device, a second angle sensor for detecting the rotation angle of the steering wheel assembly (1), and a steering controller connected to both the first angle sensor and the second angle sensor for changing the rotation angle of the driving device so that the theoretical value is equal to the first actual value and the second actual value when the theoretical value for driving the steering wheel assembly (1) to rotate is not equal to the first actual value detected by the first angle sensor and the second actual value detected by the second angle sensor; when the theoretical value for driving the steering wheel assembly (1) to rotate is equal to the first actual value detected by the first angle sensor and the second actual value detected by the second angle sensor, the state of the driving device is maintained; when one of the two angle sensors fails, the values ​​detected by the remaining angle sensor are compared to ensure that the vehicle can operate normally.

2. The omnidirectional forklift steering wheel mechanism according to claim 1, characterized in that: The large gear (4) and the small gear (20) are meshedly connected via a transition gear (12); the transition gear (12) is connected to the base (6) via a transition gear shaft (11); and the second angle sensor is specifically an absolute value angle sensor (18) connected to the lower end of the transition gear shaft (11).

3. The omnidirectional forklift steering wheel mechanism according to claim 2, characterized in that: A swing arm (16) having an elongated hole is connected to the notch at the lower end of the transition gear shaft (11); the eccentric shaft of the absolute angle sensor (18) is connected to the eccentric hole (171) of the coupling (17); the connecting shaft of the coupling (17) is connected to the elongated hole, and the connecting shaft moves along the elongated hole.

4. The omnidirectional forklift steering wheel mechanism according to claim 1, characterized in that: The driving device comprises a steering motor (24) and an L-shaped planetary reduction box (21) connected to the steering motor (24); the first angle sensor is specifically a counting angle sensor (25) connected to the steering motor (24).

5. The omnidirectional forklift steering wheel mechanism according to claim 1, characterized in that: It also includes a zero position detection device for detecting whether the steering wheel assembly (1) is in a zero position, the zero position detection device being connected to the steering controller, and the steering controller being used to control the steering wheel assembly (1) to return to zero position when the steering wheel assembly (1) is not in the zero position.

6. The omnidirectional forklift steering wheel mechanism according to claim 5, characterized in that: The zero position detection device comprises a detection bar (22) provided on the steering wheel assembly (1) and having a detection notch (23), and a zero position sensor (3) located below the detection bar (22); the zero position sensor (3) is located on the rotation radius of the detection notch (23); and the zero position sensor (3) is connected to the steering controller.

7. The omnidirectional forklift steering wheel mechanism according to claim 1, characterized in that: The steering wheel assembly (1) is provided with a stepped shaft (1-1), the large gear (4) and the inner ring of the slewing bearing (5) are connected to the stepped shaft (1-1), the bottom surface of the base (6) has a stepped hole (61), the outer ring of the slewing bearing (5) is connected to the stepped hole (61), and the steering wheel assembly (1) can rotate 360 ​​degrees.

8. The omnidirectional forklift steering wheel mechanism according to claim 2, characterized in that: The base (6) comprises a high seat and a low seat connected to the side of the high seat, the high seat and the low seat form a height difference, the high seat and the low seat have a connecting hole on the connecting side, the large gear (4) is connected to the bottom of the high seat, the transition gear (12) and the small gear (20) are connected to the top of the low seat, and the large gear (4) and the transition gear (12) are meshed at the connecting hole; The connection holes on the low seat and the high seat are processed after being welded.

9. A control method for the omnidirectional forklift steering wheel mechanism according to any one of claims 1 to 8, characterized in that: Includes steps: sending a theoretical value for driving the steering wheel assembly (1) to rotate to a steering controller; Detecting the rotation angle of the steering wheel assembly (1) and / or the rotation angle of the driving device, and feeding back the measured first actual value and / or second actual value to the steering controller; Determine whether the theoretical value is equal to the first actual value and / or the second actual value. If they are equal, maintain the rotation state of the drive device. If the values ​​are not equal, change the rotation angle of the drive device to make the theoretical value equal to the first actual value and / or the second actual value.

10. The control method according to claim 9, characterized in that: The detecting of the rotation angle of the steering wheel assembly (1) and / or the rotation angle of the driving device comprises: It is determined whether the first angle sensor and the second angle sensor are working normally. If the first angle sensor is working normally, the first angle sensor is used to detect the rotation angle of the steering wheel assembly (1); if the first angle sensor is not working normally, the second angle sensor is used to detect the rotation angle of the drive device.

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