Torque and angle sensing system and electric power steering system

Abstract

The utility model provides a torque and angle sensing system and an electric power steering system. The torque and angle sensing system comprises a gear set, a rotor set, a torsion bar and a control module, and the two ends of the torsion bar are fixedly connected with an input shaft and an output shaft respectively. The rotor set comprises an input shaft rotor, a PCB assembly and an output shaft rotor which are coaxially arranged. The gear set comprises a driving gear and a driven gear; the control module is used for measuring the torque and the absolute angle according to the rotation angles of the input shaft rotor and the output shaft rotor and the rotation angle of the driven gear. The utility model further provides an electric power steering system comprising the torque and angle sensing system. After the technical scheme is adopted, the measurement range of the torque of the input shaft and the output shaft is effectively expanded; and the absolute angle range of the steering wheel can be expanded, and the torque and angle use requirements of market engineering vehicles are met.

Description

Technical Field

[0001] The utility model relates to the field of sensors, in particular to a torque and angle sensing system and an electric power steering system. Background Art

[0002] In recent years, the steering field of vehicle engineering has increasingly higher requirements for intelligence, informationization, integration, and safety level. Household vehicles have transitioned from power steering to intelligent steering, and intelligent steering will become standard in the near future. At the same time, engineering vehicles, fire trucks, and military vehicles have greater requirements for large turning angles. Under this development situation, this requires matching the accuracy, breadth, perception, and redundancy of torque and angle signals. However, the existing torque angle sensors used for EPS have the following shortcomings:

[0003] The fields of intelligent driving and steer-by-wire require damping control, redundant arbitration, command superposition, steering wheel position coordination, etc., and the requirements for redundancy and precision are becoming increasingly higher.

[0004] Therefore, with the advent of the era of unmanned intelligent driving, the vehicle steering system is required to meet the requirements of a large torque measurement range and a wide steering angle, while also requiring redundant arbitration, command superposition, steering wheel position coordination, etc., redundancy accuracy, early warning of faults, strong anti-electromagnetic interference ability, and little influence by temperature. Therefore, a new torque and angle measurement system for vehicle engineering is needed, which can not only expand the measurement range of torque and absolute angle, but also meet redundancy and accuracy. Utility Model Content

[0005] The utility model aims to provide a torque and angle sensing system, comprising: a gear set, a rotor set, a torsion bar and a control module, wherein the two ends of the torsion bar are respectively fixedly connected to an input shaft and an output shaft, the rotor set comprises a coaxially arranged input shaft rotor, a PCB board assembly and an output shaft rotor, the PCB board assembly comprises a first PCB board and a second PCB board with independent communication channels, the first PCB board and the second PCB board are both provided with an excitation coil, a receiving coil, a first chip and a second chip, the input shaft rotor is fixed to the input shaft, the output shaft is fixed to the output shaft, and the torsion bar passes through the input shaft rotor, the PCB board assembly and the output shaft rotor in sequence;

[0006] The gear set includes a driving gear and a driven gear, wherein the driving gear is fixedly connected to the input shaft rotor and rotates synchronously with the input shaft, and the driven gear meshes with the driving gear, and the driven gear includes a magnet;

[0007] The first chip is used to receive the rotation angles of the input shaft rotor and the output shaft rotor, the second chip is used to determine the rotation angle of the driven gear according to the rotation angle of the magnet, and the control module is used to measure the torque and the absolute angle according to the rotation angles of the input shaft rotor and the output shaft rotor and the rotation angle of the driven gear;

[0008] Preferably, the input shaft rotor comprises p first metal blades uniformly distributed along the circumferential direction, extending in a radial direction away from the torsion bar; the output shaft rotor comprises q second metal blades uniformly distributed along the circumferential direction, extending in a radial direction away from the torsion bar, wherein p / q is 2;

[0009] Preferably, the gear meshing ratio between the driving gear and the driven gear is 45:37;

[0010] Preferably, the excitation coil is used to generate a measuring magnetic field;

[0011] The receiving coil and the exciting coil are arranged on the same end surface, and are used to measure the induced voltage generated by the input shaft rotor and the output shaft rotor cutting the measuring magnetic field;

[0012] The first chip is used to receive the induced voltage to measure the rotation angle of the input shaft rotor and the rotation angle of the output shaft rotor;

[0013] Preferably, the first chip is used to determine the second angle information of the input shaft rotating with a period of 360° / q according to the first angle information of the output shaft rotating;

[0014] The second chip is used to determine the third angle information of the driven gear rotating with a period of 296° according to the rotation angle of the magnet;

[0015] The control module is used to determine the torque according to the rotation angles of the input shaft rotor and the output shaft rotor, and is used to measure the absolute angle according to the second angle information and the third angle information;

[0016] Preferably, it further comprises a housing, wherein the housing comprises a sensor cover, a housing and a gear cover;

[0017] The torsion bar passes through the gear cover, the housing and the gear cover in sequence;

[0018] The gear cover is fixed to the housing, and the first accommodation space formed therein is used to accommodate the gear set;

[0019] The sensor cover is fixed to the housing, and the formed second accommodation space is used to accommodate the input shaft rotor and the PCB board assembly;

[0020] The output shaft rotor is fixed to a side surface of the sensor cover away from the housing.

[0021] Preferably, p=10, q=5.

[0022] Another aspect of the utility model further discloses an electric power steering system, comprising any of the torque and angle sensing systems described above. Compared with the prior art, the above technical solution has the following beneficial effects:

[0023] The technical solution in the utility model can effectively combine two technologies, namely non-contact electric induction technology and Hall magnetic induction technology. Among them, the electric induction technology is used for the measurement signal measured at a period of 72° and 36°, and the Hall magnetic induction technology is applied to the measurement signal measured at a period of 296°, which can effectively expand the measurement range of the torque of the input shaft and the output shaft; when used in vehicles, it can expand the absolute angle range of the steering wheel to meet the market demand for torque and angle use of engineering vehicles. The PCB board assembly adopts a redundant design, so that the electric power steering system (EPS) equipped with the above-mentioned torque angle sensor can meet the redundancy and signal accuracy requirements of electric vehicles for intelligent / assisted driving solutions, and can also meet the requirements of professional engineering vehicles and unmanned driving with higher measurement accuracy. It can be used for power steering of mainstream vehicles and future wire control steering, and can also expand unmanned passenger cars, special vehicles such as fire trucks, ambulances, warehouses or parks non-fixed track unmanned delivery vehicles, and vehicles that require precise steering in explosive environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of a rotor assembly in an embodiment consistent with the present utility model;

[0025] Figure 2 for Figure 1 A schematic diagram of the rotor assembly shown;

[0026] Figure 3 for Figure 1 An exploded view of the torque angle sensor of the illustrated embodiment;

[0027] Figure 4 for Figure 1 A schematic diagram of the calculation principle of the illustrated embodiment;

[0028] Figure 5 for Figure 1 A schematic diagram of a PCB board assembly in the illustrated embodiment.

[0029] Reference numerals:

[0030] 1-input shaft rotor, 11-first metal blade, 2-PCB board assembly, 21-excitation coil, 22-receiving coil, 23-first chip, 3-output shaft rotor, 31-second metal blade, 4-input shaft, 5-output shaft, 61-driving gear, 62-driven gear, 7-torsion bar, 8-sensor cover, 9-housing, 10-gear cover. DETAILED DESCRIPTION

[0031] The advantages of the present invention are further described below in conjunction with the accompanying drawings and specific embodiments.

[0032] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0033] It should be understood that although the terms first, second, third, etc. may be used in the present disclosure to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present disclosure, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0034] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0035] In the description of the present utility model, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection of two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0036] An embodiment of the utility model provides a torque and angle sensing system, comprising: a gear set, a rotor set, a torsion bar and a control module, wherein two ends of the torsion bar are fixedly connected to an input shaft and an output shaft respectively.

[0037] like Figure 1 , Figure 2 As shown, the rotor group includes a coaxially arranged input shaft rotor 1, a PCB board assembly 2 and an output shaft rotor 3, the PCB board assembly 2 includes a first PCB board and a second PCB board with independent communication channels, the first PCB board and the second PCB board are both provided with an excitation coil 21, a receiving coil 22, a first chip 23 and a second chip (not shown in the figure), the input shaft rotor 1 is fixed to the input shaft 4, the output shaft 5 is fixed to the output shaft 5, and the torsion bar 7 passes through the input shaft rotor 1, the PCB board assembly 2 and the output shaft rotor 3 in sequence. Since the first PCB board and the second PCB board are redundantly designed, the two are exactly the same in structure and function, so in the following description, only the function and structure of one of the PCB boards are described. In this embodiment, since the PCB board assembly adopts a redundant design, such as Figure 5 As shown, the channels of the first PCB board and the second PCB board are completely isolated, with independent power supply and independent line direction without interfering with each other. In actual use, even if the first channel fails, there is a redundant second channel module to replace it, so that the safety performance of the power vehicle during driving is effectively improved. In addition, the first PCB board and the second PCB board in this embodiment are connected to the vehicle's power steering assembly using a 10-pin interface, and use the SAE2716 international standard communication protocol, which can be quickly adapted to the vehicle bus communication and expanded to other sensor systems.

[0038] The input shaft rotor 1 includes p first metal blades 11 uniformly distributed along the circumference, extending in a radial direction away from the torsion bar 7; the output shaft rotor 3 includes q second metal blades 31 uniformly distributed along the circumference, extending in a radial direction away from the torsion bar 7, where p / q is 2. The advantage of the number of first metal blades 11 being twice the number of second metal blades 31 is that the period angle of the input shaft rotor 1 is half the period angle of the output shaft rotor 3, and they will not interfere with each other. At the same time, the signal period sensed on the PCB board within one circle of the input shaft (360°) and the number of metal blades on the input shaft rotor are in a fixed proportional integer relationship, so that the abnormal blades attached to the input shaft can be detected and compensated, ensuring that the signal used for calculation is true and effective. In this embodiment, p=10, q=5. The excitation coil 21 is arranged on the PCB board assembly 2 to generate the measuring magnetic field; the receiving coil 22 is arranged on the PCB board assembly 2 and is arranged on the same end surface as the excitation coil 21 to measure the induced voltage generated by the input shaft rotor 1 and the output shaft rotor 3 cutting the measuring magnetic field.

[0039] The gear set includes a driving gear 61 and a driven gear 62. The driving gear 61 is fixedly connected to the input shaft rotor 1 and rotates synchronously with the input shaft 4. The driven gear 62 meshes with the driving gear 61. The driven gear 62 also includes a magnet. The second chip is used to determine the rotation angle of the driven gear 62 according to the rotation angle of the magnet. In this embodiment, the gear meshing ratio of the driving gear 61 and the driven gear 62 is 45:37. Therefore, when the steering wheel rotates 360°, the driving gear 61 is also driven to rotate 360°, and the driven gear 62 rotates 296° accordingly. The second chip can measure the rotation angle signal of the driven gear 62. It should be particularly noted that in this embodiment, the signals sensed by the first chip, the second chip on the first PCB board and the first chip and the second chip on the second PCB board can be checked synchronously with each other after normalization processing, and the chip operation status is reversely checked, which can be used to diagnose the operation status of the chip.

[0040] The control module is used to measure the torque and the absolute angle according to the rotation angles of the input shaft rotor 1 and the output shaft rotor 3 and the rotation angle of the driven gear 62 .

[0041] In actual applications, the input shaft 4 and the output shaft 5 of the vehicle steering column are connected by a torsion bar 7. When the steering wheel is subjected to force, the torsion bar 7 will deform, and the deformation is proportional to the torque applied to the steering wheel. The proportional coefficient is the stiffness coefficient of the torsion bar 7, which is a constant. Therefore, the magnitude of the loaded torque can be determined by determining the deformation of the torque. In this embodiment, the rotation angle of the input shaft rotor 1 is 36° as a measurement cycle, and the rotation angle of the output shaft rotor 3 is 72° as a measurement cycle. The first chip 23 measures these two angles, and calculates the difference between the two angles at the same time according to the angle difference principle to obtain the deformation of the torsion bar 7. Theoretically, the deformation range is ±18°. Considering the existence of mechanical limits in the input shaft 4 and the output shaft 5 and the needs in actual applications, the range of the differential angle can be controlled to ±10°.

[0042] Therefore, this embodiment uses the rotation angles of the input shaft rotor 1 and the output shaft rotor 3 measured by the first chip 23 on the PCB board assembly 2, and the torque information obtained by measuring the deformation of the torsion bar 7 according to the angle difference principle. The angle information measured by the first chip 23 has high accuracy, but the measurement range is small. In order to increase the range of the measured angle, the rotation angle of the driven gear 62 measured by the second chip can be used to determine the absolute angle. The specific calculation steps are:

[0043] First, the rotation angle of the output shaft rotor 3 is related to the absolute angle of rotation of the output shaft 5. Considering the influence of the deformation of the torsion bar 7, the first angle information of the rotation angle of the output shaft rotor 3 is added to the differential angle of the deformation of the torsion bar 7, and the angle information of the input shaft 4 with a period of 72° (360° / q) can be obtained, that is, the second angle information. Through such calculation, the first angle information of the output shaft 5 with a period of 72° is converted into the second angle information of the input shaft 4 with a period of 72°.

[0044] Then, in this embodiment, on the premise of obtaining the second angle information of the input shaft 4 with a period of 72° and the third angle information of the driven gear 62 with a period of 296°, the absolute angle of rotation of the input shaft 4 can be determined. Figure 4 , the least common multiple of 72° and 296° is 2664°, that is, the calculation starts from the 0° point at the same time, then after the second angle information with a period of 72° has gone through 37 cycles, and the third angle information with a period of 296° has gone through 9 cycles, it will once again return to the starting point of the two angle signals at the same time. Therefore, within the range of 2664°, the angle information with a period of 72° and 296° at any position is the only corresponding pair of relationships. This is the principle of the vernier algorithm. Through the vernier algorithm, the absolute angle of the input shaft 4, that is, the steering wheel, in the range of 0° to 2664° can be determined based on the second angle information and the third angle information.

[0045] Based on the above, it can be seen that the torque and angle sensing system in this embodiment can achieve a large torque measurement range, which can at least meet the torque measurement range of ±10 degrees, and can meet the use requirements of almost all models on the market. At the same time, the measurement range of the absolute angle of the steering wheel can be expanded to more than 7 circles, which can also meet the use requirements of almost all models on the market.

[0046] Figure 4 The exploded diagram of the torque and angle sensing system in this embodiment. The torque and angle sensing system in this embodiment also includes a supporting housing, which includes a sensor cover 8, a housing 9 and a gear cover 10. As shown in the figure, the torsion bar 7 passes through the gear cover 10, the housing 9 and the gear cover 10 in sequence; the gear cover 10 is fixed to the housing 9, and the first accommodation space formed is used to accommodate the gear set; the sensor cover 8 is fixed to the housing 9, and the second accommodation space formed is used to accommodate the input shaft rotor 1 and the PCB board assembly 2; the output shaft rotor 3 is fixed to the side of the sensor cover 8 away from the housing 9.

[0047] In another embodiment of the present invention, an electric power steering system is provided, comprising the torque and angle sensing system in the previous embodiment. Its technical features are the same as those of the torque and angle sensing system, and the present invention will not elaborate on them here.

[0048] It should be noted that the embodiments of the present invention have better practicability and do not impose any form of limitation on the present invention. Any technician familiar with the field may use the technical content disclosed above to change or modify it into an equivalent effective embodiment. However, any modification or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A torque and angle sensing system comprising: A gear set, a rotor set, a torsion bar and a control module, wherein the two ends of the torsion bar are fixedly connected to the input shaft and the output shaft respectively, and the characteristics are: The rotor group includes a coaxially arranged input shaft rotor, a PCB board assembly and an output shaft rotor, the PCB board assembly includes a first PCB board and a second PCB board with independent communication channels, the first PCB board and the second PCB board are both provided with an excitation coil, a receiving coil, a first chip and a second chip, the input shaft rotor is fixed to the input shaft, the output shaft is fixed to the output shaft, and the torsion bar passes through the input shaft rotor, the PCB board assembly and the output shaft rotor in sequence; The gear set includes a driving gear and a driven gear, wherein the driving gear is fixedly connected to the input shaft rotor and rotates synchronously with the input shaft, and the driven gear meshes with the driving gear, and the driven gear includes a magnet; The first chip is used to receive the rotation angle of the input shaft rotor and the output shaft rotor, the second chip is used to determine the rotation angle of the driven gear according to the rotation angle of the magnet, and the control module is used to measure the torque and absolute angle according to the rotation angle of the input shaft rotor and the output shaft rotor and the rotation angle of the driven gear.

2. The torque and angle sensing system according to claim 1, characterized in that: The input shaft rotor includes p first metal blades evenly distributed along the circumferential direction, extending in a radial direction away from the torsion bar; the output shaft rotor includes q second metal blades evenly distributed along the circumferential direction, extending in a radial direction away from the torsion bar, where p / q is 2.

3. The torque and angle sensing system of claim 2, wherein: The gear meshing ratio of the driving gear and the driven gear is 45:

37.

4. The torque and angle sensing system of claim 3, wherein: The excitation coil is used to generate a measuring magnetic field; The receiving coil and the exciting coil are arranged on the same end surface, and are used to measure the induced voltage generated by the input shaft rotor and the output shaft rotor cutting the measuring magnetic field; The first chip is used to receive the induced voltage to measure the rotation angle of the input shaft rotor and the rotation angle of the output shaft rotor.

5. The torque and angle sensing system of claim 4, wherein: The first chip is used to determine the second angle information of the input shaft rotating with a period of 360° / q according to the first angle information of the output shaft rotating; The second chip is used to determine the third angle information of the driven gear rotating with a period of 296° according to the rotation angle of the magnet; The control module is used to determine the torque according to the rotation angles of the input shaft rotor and the output shaft rotor, and is used to measure the absolute angle according to the second angle information and the third angle information.

6. The torque and angle sensing system according to any one of claims 1 to 5, characterized in that: Also included is a housing, the housing including a sensor cover, a housing, and a gear cover; The torsion bar passes through the gear cover, the housing and the gear cover in sequence; The gear cover is fixed to the housing, and the first accommodation space formed therein is used to accommodate the gear set; The sensor cover is fixed to the housing, and the formed second accommodation space is used to accommodate the input shaft rotor and the PCB board assembly; The output shaft rotor is fixed to a side surface of the sensor cover away from the housing.

7. The torque and angle sensing system of claim 2, wherein: Said p=10, q=5.

8. An electric power steering system, characterized in that: Comprising a torque and angle sensing system as described in any one of claims 1-7.

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