Angle sensor capable of compensating for abnormal angle detection unit

Abstract

The present invention relates to an angle sensor capable of compensating for an abnormal angle detection unit. More specifically, the present invention relates to an angle sensor for deriving an absolute angle of a main gear rotating with a steering shaft of a vehicle, the angle sensor being characterized in that, if a second angle detection unit for detecting the angle of a second sub-gear in a driving mode is abnormal, the absolute angle is calculated using the detected angle of a first angle detection unit for detecting the angle of a first sub-gear.

Description

Angle sensor capable of supplementing the abnormal angle detection unit

[0001] The present invention relates to an angle sensor for deriving the absolute angle of a main gear rotating together with the steering shaft of a vehicle, and to an angle sensor capable of compensating for abnormal angle detection.

[0002] A vehicle's steering system is a device that changes the direction of the steering wheels through a steering wheel to change the direction of travel of a moving vehicle.

[0003] Recent steering systems utilize electric power steering systems (EPS), which include a steering angle measuring device.

[0004] The steering angle measuring device includes an angle sensor, and this angle sensor measures the degree of steering (absolute angle) of the steering wheel required for controlling the vehicle while it is in motion.

[0005] Figure 1 illustrates a general angle sensor, where (a) shows the structure of the angle sensor, (b) shows the structure of the sub-gear, and (c) shows the magnet detection structure.

[0006] Referring to FIG. 1 (a), the angle sensor is composed of a ring-shaped main gear (20) that rotates together with the steering axis of the vehicle, a first sub-gear (21) that meshes with the main gear (20), and a second sub-gear (22) that meshes with the first sub-gear (21).

[0007] The steering shaft of the vehicle is coupled to the center of the main gear (20) and rotates together with it. When the main gear (20) rotates, the first sub-gear (21) rotates in the reverse direction of the main gear (20), and accordingly, the second sub-gear (22) rotates in the forward direction.

[0008] Referring to Fig. 1(b), a first magnet (31) and a second magnet (32) are fixed to the ends of the rotational axes of the first sub-gear (21) and the second sub-gear (22), respectively.

[0009] Referring to Fig. 1(c), the center (i.e., rotation axis) of the first magnet (31) and the second magnet (32) is positioned to face the first angle detection unit (41) and the second angle detection unit (42), respectively, mounted on a printed circuit board (not shown).

[0010] When the main gear (20) rotates, the change in magnetic force due to the rotation of the first magnet (31) and the second magnet (32) is transmitted to the first angle detection unit (41) and the second angle detection unit (42), and thus the first angle detection unit (41) and the second angle detection unit (42) each output a sensing signal.

[0011] Figure 2 is a block diagram of an angle sensor according to Figure 1.

[0012] Referring to FIG. 2, each sensing signal of the first angle detection unit (41) and the second angle detection unit (42) is input to the control unit (100), and the control unit (100) calculates the absolute angle using these two input signals.

[0013] The control unit (100) can store and read operation values ​​in an EEPROM (103, non-volatile memory, Electrically Erasable and Programmable ROM).

[0014] The control unit (100) also controls the wheel drive unit (110) to switch the EPS system to drive or manual mode, and when driven in manual mode, it illuminates a warning light (105) to notify the driver of an emergency situation.

[0015] Figure 3 illustrates a flowchart of the control unit according to Figure 2.

[0016] Referring to FIG. 3, the control unit (100) first checks whether it is in assembly calibration mode, and if it is in assembly calibration mode, stores the calibration value, which is the difference between the actual angle of the steering shaft where the vehicle is assembled and the angle measured by the angle sensor, i.e., the difference (C2) between the absolute angle of the second sub-gear (22) and the actual angle of the wheel, in the EEPROM (103).

[0017] This calibration value is used for correction when calculating the absolute angle.

[0018] For example, when assembling a vehicle, if the actual wheel mechanism angle is 0 degrees and the angle of the angle sensor (based on the second sub-gear) is 150 degrees, 150 degrees is stored in the EEPROM (103) and the wheel angle is calculated as follows.

[0019] [Wheel's absolute angle = Absolute angle calculated in real-time by angle sensor - 150 degrees]

[0020] Next, the control unit (100) checks whether it is in start mode, and if it is in start mode, checks whether both the first angle detection unit (41) and the second angle detection unit (42) are normal, and if one or more of the two are abnormal, switches to manual wheel mode and lights up the warning light.

[0021] Therefore, the driver can recognize that there is an abnormality in the angle sensor when starting the engine and drive by responding appropriately in manual wheel mode.

[0022] If both the first angle detection unit (41) and the second angle detection unit (42) are normal, the second absolute angle (A2) is calculated using the angles of the first sub-gear (21) and the second sub-gear (22) based on the second sub-gear (22).

[0023] The absolute angle (A) of the wheel can be obtained by correcting the difference (C2) calculated in assembly calibration mode to the second absolute angle (A2) calculated based on the second sub-gear (22).

[0024] Next, the control unit (240) checks whether it is in driving mode. If it is in driving mode, it checks whether the second angle detection unit (42) is normal. If it is normal, it performs an absolute angle calculation using the angle of the second sub-gear (22). If it is not normal, it switches to manual wheel mode and lights up a warning light.

[0025] However, if the second angle detection unit (42) is not normal in driving mode, it may cause a fatal problem for the driver.

[0026] When entering manual wheel mode, assistance is not provided by the EPS system, which may cause steering difficulties as if the steering wheel were locked. Since this is an unexpected phenomenon while driving, it can cause the driver to panic, increasing the risk of accidents.

[0027] To solve this problem, it is necessary to develop technology that allows the EPS system to maintain the assistance state without unexpectedly entering the manual wheel state even if the second angle detection unit (42) is abnormal.

[0028] The technical problem that the present invention aims to solve is to provide an angle sensor that maintains an assistance state without the EPS system unexpectedly entering a manual wheel state, even if one of the angle detection units of the angle sensor becomes abnormal during driving.

[0029] The technical problems of the present invention are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description below.

[0030] The angle sensor of the present invention for solving the above technical problem comprises a main gear that rotates together with the steering shaft of a vehicle, a first sub-gear and a second sub-gear that are linked to the main gear, a first angle detection unit and a second angle detection unit that detect the angles of the first sub-gear and the second sub-gear, and a control unit that calculates and outputs an absolute angle using the detected angles of the first angle detection unit and the second angle detection unit, wherein the control unit can calculate an absolute angle using the detected angle of the first angle detection unit when the second angle detection unit is abnormal.

[0031] In some embodiments of the present invention, the control unit can calculate the respective absolute angles based on the first sub-gear and the second sub-gear in a start mode.

[0032] In some embodiments of the present invention, the absolute angle may be corrected by a calibration value which is the difference between the absolute angle based on the first sub-gear or the second sub-gear and the actual wheel angle.

[0033] In some embodiments of the present invention, the calibration value may be detected and stored in a separate assembly calibration mode.

[0034] In some embodiments of the present invention, the control unit can calculate an absolute angle with respect to the angle of the first sub-gear when the second angle detection unit is abnormal and the first angle detection unit is normal in driving mode.

[0035] In some embodiments of the present invention, the control unit may switch to manual wheel mode and illuminate a warning light when both the first angle detection unit and the second angle detection unit are abnormal in driving mode.

[0036] In some embodiments of the present invention, the control unit may store a calibration value in a non-volatile memory which is the difference between the absolute angle based on the first sub-gear or the second sub-gear and the actual wheel angle in an assembly calibration mode.

[0037] According to the angle sensor of the present invention, even if one angle detection unit of the angle sensor becomes abnormal during driving, absolute angle calculation is continuously performed using the output of another angle detection unit, thereby allowing the EPS system to maintain an assistance state without unexpectedly entering a manual wheel state. Therefore, the function of the EPS system is maintained even in the event of a failure of the angle detection unit, thereby preventing car accidents that may occur when the driver becomes flustered due to an unexpected switch to a manual wheel mode during driving.

[0038] Figure 1 illustrates a typical angle sensor.

[0039] Figure 2 is a block diagram of an angle sensor according to Figure 1.

[0040] Figure 3 is a control flow chart of the control unit according to Figure 2.

[0041] FIG. 4 is a control flow chart of a control unit according to one embodiment of the present invention.

[0042] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components.

[0043] "And / or" includes each of the mentioned items and all combinations of one or more.

[0044] The terms used herein are for describing embodiments and are not intended to limit the invention. In this specification, the singular form includes the plural form unless specifically stated otherwise in the text. As used herein, "comprising" and / or "comprising" does not exclude the presence or addition of one or more other components, steps, actions, and / or elements to the mentioned components, steps, actions, and / or elements.

[0045] Furthermore, throughout the specification, when a part is described as being "connected" to another part, this includes not only cases where they are "directly connected," but also cases where they are "indirectly" or "electrically connected" with other members or elements in between.

[0046] Additionally, throughout the specification, the description that each layer (film), region, pattern, or structure is formed "on" or "under" the substrate, each layer (film), region, pad, or pattern includes both direct formation and formation through another layer. The criteria for "on" or "under" each layer are described based on the drawings.

[0047] Furthermore, expressions such as 'first, second,' etc., are used solely to distinguish multiple compositions and do not limit the order or other characteristics between the compositions.

[0048] Unless otherwise defined, all terms used in this specification (including technical and scientific terms) may be used in a meaning commonly understood by those skilled in the art to which the present invention pertains. Additionally, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0049] Hereinafter, an angle sensor capable of supplementing the abnormal angle detection unit according to the present invention will be described with reference to the drawings.

[0050] Figure 1 illustrates a general angle sensor, and Figure 2 is a block diagram of the angle sensor according to Figure 1.

[0051] FIG. 4 is a control flow chart of a control unit according to one embodiment of the present invention.

[0052] The present invention can utilize the mechanical structure of a general angle sensor and the sensing and control circuit composed of electronic components of FIGS. 1 and FIG. 2 as is.

[0053] Referring to FIGS. 1, 2 and 4, the angle sensor according to the present invention comprises a main gear (20) that rotates together with the steering shaft of a vehicle, a first sub-gear (21) and a second sub-gear (22) linked to the main gear (20), a first angle detection unit (41) and a second angle detection unit (42) that detect the angles of the first sub-gear (21) and the second sub-gear (22), and a control unit (100) that calculates and outputs an absolute angle using the detected angles of the first angle detection unit (41) and the second angle detection unit (42). The control unit can calculate an absolute angle using the detected angle of the first angle detection unit (41) when the second angle detection unit (42) is abnormal.

[0054] Figure 1 shows a general angle sensor, where (a) shows the structure of the angle sensor, (b) shows the structure of the sub-gear, and (c) shows the magnet detection structure.

[0055] Referring to FIG. 1 (a), the angle sensor may include a ring-shaped main gear (20) that rotates together with the steering axis of the vehicle, a first sub-gear (21) that meshes with the main gear (20), and a second sub-gear (22) that meshes with the first sub-gear (21).

[0056] The steering shaft of the vehicle is coupled to the center of the main gear (20) and rotates together with it. As the main gear (20) rotates, the first sub-gear (21) rotates in the opposite direction to the rotation direction of the main gear (20), and accordingly, the second sub-gear (22) rotates in the forward direction.

[0057] It is preferable that the first sub-gear (21) and the second sub-gear (22) have a gear ratio of 1:1, taking into account the accuracy of the rotation amount measurement and the arrangement relationship.

[0058] Referring to Fig. 1(b), a first magnet (31) and a second magnet (32) are fixed to the ends of the rotational axes of the first sub-gear (21) and the second sub-gear (22), respectively.

[0059] Referring to Fig. 1(c), the center (i.e., rotation axis) of the first magnet (31) and the second magnet (32) is positioned opposite to the first angle detection unit (41) and the second angle detection unit (42) mounted on a printed circuit board (not shown).

[0060] The change in magnetic force resulting from the rotation of the first magnet (31) and the second magnet (32) linked to the rotation of the main gear (20) is transmitted to the first angle detection unit (41) and the second angle detection unit (42), and thus the first angle detection unit (41) and the second angle detection unit (42) each output a sensing signal.

[0061] The angle detection unit (41, 42) outputs an electrical signal indicating the rotation angle when the center (i.e., rotation axis) of the first magnet (31) and the second magnet (32) rotates. Here, a magnetoresistance sensor, specifically an anisotropic magnetoresistance sensor, may be used as the angle detection unit (41, 42), or a Hall IC may be used. However, it is not limited to this, and any sensor capable of detecting the rotation angle may be used as the angle detection unit (41, 42) of the present invention.

[0062] Figure 2 is a block diagram of an angle sensor according to Figure 1.

[0063] Referring to FIG. 2, each sensing signal of the first angle detection unit (41) and the second angle detection unit (42) is input to the control unit (100), and the control unit (100) can calculate the absolute angle using the two sensing signals.

[0064] The control unit (100) may include a microcontroller, a storage device, and peripheral circuits. The control unit (100) can perform a measurement operation of the angle sensor according to the present invention by means of a microcontroller that executes a program stored in the storage device.

[0065] The control unit (100) can store and read operation values ​​in an EEPROM (103, non-volatile memory, Electrically Erasable and Programmable ROM).

[0066] The control unit (100) also controls the wheel drive unit (110) to switch the EPS system to drive or manual mode, and when driven in manual mode, it illuminates a warning light (105) to notify the driver of an emergency situation.

[0067] FIG. 4 is a control flow chart of a control unit according to one embodiment of the present invention.

[0068] Referring to FIG. 4, the control unit (100) first checks whether the current mode is assembly calibration mode, and if it is assembly calibration mode, stores the calibration value, which is the difference between the actual angle of the steering shaft where the vehicle is assembled and the angle measured by the angle sensor, i.e., the difference (C2) between the absolute angle based on the second sub-gear (22) and the actual angle of the wheel, in the EEPROM (103). At this time, the difference (C1) between the absolute angle based on the first sub-gear (21) and the actual angle of the wheel can also be stored together in the EEPROM (103).

[0069] Due to the error between the first sub-gear (21) and the second sub-gear (22), a difference occurs between the absolute angle based on the second sub-gear (22) and the absolute angle based on the first sub-gear (21). In driving mode, when the second angle detection unit (42) is determined to be abnormal, it is desirable to store both calibration values ​​so that when changing from the absolute angle based on the second sub-gear (22) to the absolute angle based on the first sub-gear (21), the correction value can also be changed accordingly.

[0070] As such, the control unit (100) according to the present invention may be characterized by storing a calibration value, which is the difference between the absolute angle based on the first sub-gear (21) or the second sub-gear (22) and the actual angle of the wheel, in a non-volatile memory in an assembly calibration mode.

[0071] The two calibration values ​​above are later used for correction when calculating the absolute angle in other modes.

[0072] For example, when assembling a vehicle, if the mechanism angle of the vehicle's wheel is 0 degrees, and the absolute angle based on the second sub-gear (22) is 150 degrees, then 150 degrees is stored as C2 in the EEPROM (103), and if the absolute angle based on the first sub-gear (21) is 153 degrees, then 153 degrees is stored as C1 in the EEPROM (103).

[0073] Using this calibration value, the wheel angle can be calculated using the following formula.

[0074] Absolute angle of the wheel = Absolute angle calculated in real-time based on the 2nd sub-gear - 150 degrees (C2),

[0075] Or absolute angle of the wheel = absolute angle calculated in real-time based on the first sub-gear - 153 degrees (C1)

[0076] Previously, if the current mode is not assembly calibration mode, the control unit (100) checks again whether the current mode is start mode. If it is start mode, it checks whether both the first angle detection unit (41) and the second angle detection unit (42) are normal. If one or more of the two are abnormal, it switches to manual wheel mode and lights up a warning light.

[0077] Therefore, the driver can be aware that there is an abnormality in the angle sensor when starting the engine and drive by responding appropriately in manual wheel mode.

[0078] If both the first angle detection unit (41) and the second angle detection unit (42) are normal, the second absolute angle (A2) is calculated using the angles of the first sub-gear (21) and the second sub-gear (22) based on the second sub-gear (22).

[0079] The absolute angle (A2) of the wheel can be obtained by reflecting the difference (C2) calculated in the assembly calibration mode prior to the second absolute angle (A2) calculated based on the second sub-gear (22). (A2-C2 → A2)

[0080] At this time, the first absolute angle (A1) can also be calculated using the angle between the first sub-gear (21) and the second sub-gear (22) based on the first sub-gear (21).

[0081] The absolute angle (A1) of the wheel can be obtained by reflecting the difference (C1) calculated in assembly calibration mode to the first absolute angle (A1) calculated based on the first sub-gear (21). (A1-C1 → A1)

[0082] In this way, the control unit (100) can calculate two absolute angles (A1, A2) based on the first sub-gear (21) and the second sub-gear (22), respectively, and store and retain both of them. By retaining these two absolute angles (A1, A2), the control unit can be made to operate by changing accordingly when the second angle detection unit (42) is determined to be abnormal in driving mode and changes from the absolute angle based on the second sub-gear (22) to the absolute angle based on the first sub-gear (21).

[0083] As such, the control unit (100) according to the present invention can calculate the respective absolute angles based on the first sub-gear (21) and the second sub-gear (22) in the starting mode, and the absolute angles can be corrected by a calibration value which is the difference between the absolute angle based on the first sub-gear (21) or the second sub-gear (22) and the actual wheel angle. At this time, the calibration value may be a value stored in advance in the assembly calibration mode performed separately above.

[0084] If the current mode is not the start mode, the control unit (100) then checks whether it is the driving mode.

[0085] If the current mode is driving mode, first check whether the second angle detection unit (42) is normal, and if the second angle detection unit (42) is normal, perform an absolute angle calculation using the angle of the second sub-gear (22).

[0086] At this time, even if the second angle detection unit (42) is not normal, it does not switch directly to manual wheel mode as in the past.

[0087] Instead, the control unit checks whether the first angle detection unit is normal, and if the first angle detection unit is normal, it lights up a warning light and continues to perform absolute angle calculations with the angle of the first sub-gear (21).

[0088] In this way, the control unit (100) according to the present invention can maintain the EPS system by only illuminating the warning light and calculating the absolute angle (A) using the angle of the first sub-gear (21), even if the second angle detection unit (42) is not normal in driving mode, if the first angle detection unit is normal. At this time, the absolute angle (A) can be accurately derived using the angle of the first sub-gear (21) based on the first absolute angle (A1) calculated in starting mode.

[0089] In this way, the control unit (100) according to the present invention can calculate the absolute angle with the angle of the first sub-gear (21) when the second angle detection unit (42) is abnormal and the first angle detection unit (41) is normal in driving mode.

[0090] Meanwhile, in driving mode, if both the first angle detection unit (41) and the second angle detection unit (42) are abnormal, the system can be switched to manual wheel mode and the warning light can be turned on.

[0091] As such, the angle sensor according to the present invention allows absolute angle calculation to continue to be performed using the output of another angle detection unit even if one angle detection unit of the angle sensor becomes abnormal during driving, thereby preventing the EPS system from unexpectedly entering a manual wheel state and maintaining the assistance state. Therefore, the function of the EPS system is maintained even in a situation where the angle detection unit fails, thereby preventing fatal car accidents that may occur when the driver is startled by unexpectedly switching to a manual wheel mode while driving.

[0092] Although the present invention has been described above, those skilled in the art will recognize that the invention may be implemented in other forms while maintaining the technical concept and essential features of the invention.

[0093] The scope of the present invention shall be defined by the claims, but all modifications or variations derived from configurations directly derived from the claims, as well as configurations equivalent thereto, shall be interpreted as being included within the scope of the present invention.

Claims

1. A main gear that rotates together with the steering shaft of a vehicle; A first sub-gear and a second sub-gear linked to the main gear above; A first angle detection unit and a second angle detection unit for detecting the angles of the first sub-gear and the second sub-gear; and It includes a control unit that calculates an absolute angle using the detected angles of the first angle detection unit and the second angle detection unit, and The angle sensor is characterized in that the control unit calculates an absolute angle using the detected angle of the first angle detection unit when the second angle detection unit is abnormal.

2. In Paragraph 1, The above control unit is an angle sensor that calculates the respective absolute angles based on the first sub-gear and the second sub-gear in start mode.

3. In Paragraph 2, An angle sensor characterized in that the absolute angle is corrected by a calibration value which is the difference between the absolute angle based on the first sub-gear or the second sub-gear and the actual wheel angle.

4. In Paragraph 3, The above calibration value is an angle sensor that is detected and stored in an assembly calibration mode performed separately.

5. In Paragraph 1, The above control unit is an angle sensor that calculates an absolute angle using the angle of the first sub-gear when the second angle detection unit is abnormal and the first angle detection unit is normal in driving mode.

6. In Paragraph 5, The above control unit is an angle sensor that switches to manual wheel mode and illuminates a warning light when both the first angle detection unit and the second angle detection unit are abnormal in driving mode.

7. In Paragraph 1, The angle sensor, characterized in that the control unit stores a calibration value in a non-volatile memory, which is the difference between the absolute angle based on the first sub-gear or the second sub-gear and the actual wheel angle in an assembly calibration mode.

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