Fail-Operational Steering Angle Sensor

Abstract

This application describes a fail-operational steering angle sensor for a vehicle. The fail-operational steering angle sensor comprises a central gear (hub) and two outer gears (Gear 1 and Gear 2) mechanically connected to the hub. The two outer gears have magnetic properties and are located in the vicinity of a printed circuit board (PCB). The fail-operational SAS is connected to a steering wheel actuator shaft. The steering wheel actuator shaft imparts angular rotation to the above moving parts by mechanical connections of the central gear, the two outer gears, and a rotor located between the central gear and the PCB. The variations in magnetic field and magnetic flux resulting from the rotation of the mechanical parts are determined by the PCB.

Description

Detailed Description of the Invention

[0001] [Technical Field] This application describes a fail-operational steering angle sensor for a vehicle. [Background technology]

[0002] Fail-operational behavior means that a system will continue to perform a defined set of functions to a defined extent, with a defined performance, for a defined time, in the presence of a certain amount of failure. This definition leads to the creation of a mechanical system that continues to operate for a certain period of time even if one mechanical component fails.

[0003] With the expansion of autonomous driving in the automotive market, new steering systems, especially those that meet fail-operational standards and requirements, such as steer-by-wire systems, are becoming a reality. These steering systems eliminate the steering shaft that connects the steering wheel to the rack system. In this case, the vehicle's passenger compartment contains an upper system, or steering wheel actuator (SWA), which, among other components, consists of a motor, several sensors, a steering wheel, and a shaft (SWA shaft) that connects all elements. The motor facilitates the rotation of the steering wheel while allowing the driver to continue to apply resistance. The sensors are responsible for measuring the angle and torque of the driver's hands.

[0004] By aligning multiple sensors and actuators in the lower system (Steering Rack Actuator: SRA), the driver can operate the wheel while feeling the same traditional driving experience as in a regular car, and the forces from the road surface are transmitted to the driver's hands. In addition, the steering wheel can be turned, allowing the driver to enjoy autonomous driving without turning the steering wheel.

[0005] In new steer-by-wire systems, the consequences of one of these sensors failing are much greater when compared to current steering systems with a steering shaft, where a sensor failure does not directly affect driver safety because there is always a mechanical connection between the steering elements.

[0006] These technological developments have created a need for a fail-operational sensor that accurately measures the steering wheel angle while ensuring full availability of the angle signal, regardless of failure. The perception system must continue to operate accurately until the vehicle arrives at a safe parking location or a workshop where the system can be repaired. The perception system is a device that measures the steering wheel angle and speed. The information measured by the steering angle sensor is sent to the steering control system for analysis and is used, along with information provided by other existing sensors, to control various driver assistance systems, such as electronic stability control.

[0007] Currently, if one mechanical component of a SAS fails, the entire sensor will fail and cease operation for safety reasons. For example, if one of two gears that operate simultaneously fails, the sensor can only read the signal from one gear, and a valid output signal cannot be obtained because both gears must provide a certain range of angles.

[0008] Aside from this known issue, to ensure accurate transmission of motion between the hub and the outer gear of the SAS, a minimum gap between the gear teeth is required to accommodate thermal expansion of the components over a wide temperature range. These gaps, along with other gaps that exist between moving parts (e.g., bearing gaps, actuation gaps, etc.), cause a physical phenomenon known as hysteresis. Hysteresis is an important parameter for these types of sensors and is primarily observed with reversals of direction / rotation of the steering wheel.

[0009] An additional and significant benefit of steer-by-wire systems, apart from the possibility of on / off modes, is the possibility of different steering ratios, i.e., the number of possible rotations of the steering wheel. The driver can select a steering driver mode, switching from comfort mode to sport mode. This change in configuration can change the number of rotations of the steering wheel, for example, from two and a half rotations left and right from the center position (comfort mode) to one rotation left and right from the center position (sport mode). This means that the sensor range can change from ±900° to ±360° depending on the driver's mode change. This possibility creates a need for increased sensor accuracy. For example, if the steering system is activated to rotate the wheel ±40°, a sensor with an angle error of 5° (partially due to hysteresis) will have an effect on the wheel of 0.22° (steering ratio 1:22.5 in comfort mode). In sport mode, the same sensor will have an effect on the wheel of 0.55° (steering ratio 1:9 in sport mode). This inaccuracy can affect the vehicle's trajectory, especially when operating in sport mode.

[0010] Currently, in existing steering systems, there is no delay in wheel movement because the steering wheel and the wheels are physically connected. When the driver operates the steering wheel, the force is transmitted to the wheels via the steering shaft. Therefore, in conventional systems, the SAS reads the driver's intention and sends a signal of the driver's intention. Ultimately, there is a slight deviation in the angle, but it does not have a significant impact on the driver's intention. However, if the steering shaft is removed, there is no physical connection between the steering wheel and the wheels.

[0011] Applying the current SAS to new steer-by-wire systems, with the aforementioned lack of sensor accuracy, could directly affect the position of the vehicle's wheels, resulting in a poor driving experience and performance, and in the worst case scenario, posing a potential safety risk to the driver, passengers, and pedestrians.

[0012] Therefore, the current existing SAS configuration has two major problems when it comes to directly applying it to a steer-by-wire system: one is the fact that if one component fails, the entire system will stop working, and the other is the very limited overall accuracy of the SAS. 〔summary〕

[0013] The present invention describes a fail-operational steering angle sensor for a vehicle, comprising: a disk-shaped hub with a central circular opening; at least two disk-shaped outer gears, which are gear A and gear B, mechanically connected to the disk-shaped hub by protruding teeth on the outer edges of the disk-shaped hub (130) and the at least two disk-shaped outer gears; and a printed circuit board arranged on the disk-shaped hub and the at least two disk-shaped outer gears, wherein the disk-shaped hub comprises a drive key located in the central circular opening, which mechanically engages an SWA shaft through the central circular opening and mechanically engages a disk-shaped rotor between the printed circuit board and the disk-shaped hub.

[0014] In a proposed embodiment of the present invention, the SWA shaft facilitates direct rotational movement between the disk-shaped hub and the disk-shaped rotor, and indirect, counter-rotational movement of the at least two disk-shaped outer gears due to their inherent contact points with the disk-shaped hub.

[0015] In yet another proposed embodiment of the present invention, the printed circuit board is configured to determine rotational variations of the disk-shaped hub, the disk-shaped rotor, and the at least two disk-shaped outer gears, wherein the at least two disk-shaped outer gears have different diameters and different numbers of protruding teeth.

[0016] Furthermore, in another proposed embodiment of the present invention, the at least two outer disc-shaped gears have different material properties.

[0017] In yet another proposed embodiment of the present invention, the disc-shaped rotor comprises a disc-shaped surface having a set of openings therein.

[0018] Furthermore, in another proposed embodiment of the present invention, the disk-shaped rotor has a central circular opening that extends along and above the inner wall of the central circular opening in the hub, and the disk-shaped rotor has a rotor gap that ensures mechanical alignment with the hub drive key located on the inner wall of the circular opening in the hub.

[0019] Furthermore, in another proposed embodiment of the present invention, the rotor gap mechanically aligns a steering shaft keyway and a drive key provided on the SWA shaft.

[0020] Furthermore, in another proposed embodiment of the present invention, the printed circuit board includes a set of induction coils evenly distributed in a circular arrangement on its surface and precisely aligned with a set of openings in the disk-shaped rotor. 〔overview〕

[0021] This application describes a fail-operational steering angle sensor. The proposed configuration of this disclosure solves both the state-of-the-art issues mentioned above, namely, system freezing in case of one of the components failing, and the overall accuracy of the developed system. It not only improves the signal quality by reducing the hysteresis, but also ensures a mechanical fail-operational sensor, which is the optimal solution for steer-by-wire systems.

[0022] The mechanical configuration of a current steering angle sensor (SAS) includes a central gear (hub) and two outer gears (Gear 1 and Gear 2) mechanically connected to the hub. These two outer gears have magnetic properties and are configured and mounted on a printed circuit board (PCB). Integrated circuits (ICs) are mounted on the PCB and on the two outer gears to detect variations in the magnetic field generated by the two outer gears. The hub is connected to the steering shaft by a drive key / keyway system. When a driver turns the steering wheel of the vehicle, the steering wheel rotates the hub, which in turn moves the two outer gears. Thus, the ICs mounted on the PCB can detect the angular position of the gears.

[0023] These two outer gears have different tooth counts, which, combined with the number of teeth on the hub, allows the sensor to measure and capture an angular range. This allows the vehicle to know the actual position of the steering wheel, regardless of any power cycle, known as true power on. The true power on characteristic allows the system to know exactly what the steering wheel's position is when the vehicle is powered on, for example, every time the driver turns the vehicle off with the steering wheel in a defined position. This is true even if, for some reason, the steering wheel is not in the same position before and after a power cycle.

[0024] These four components (two outer gears, a hub, and a PCB) are typically structurally supported by a housing, ensuring proper alignment and positioning of all components. Finally, a cover closes off the interior of said housing containing all the components.

[0025] In the novel concept of the present invention disclosed herein, i.e., a fail-operational SAS, two outer gears have magnetic properties but are constructed of different materials. Gear A is made of one magnetic material (Material A) and Gear B is made of a different magnetic material (Material B). Both outer gears are located below an integrated circuit (IC) containing a sensor mounted on a printed circuit board (PCB).

[0026] In addition to this configuration, the fail-operational steering angle sensor includes an additional metallic rotor located near the PCB. The rotor is comprised of a plurality of wing-like protrusions located near the PCB. The rotor also includes a cylindrical element rigidly connected to the steering wheel actuator (SWA) shaft. Near the rotor wing-like protrusions on the PCB are a plurality of Cooper coils connected to a specific IC configured to detect changes in magnetic flux when the metallic rotor rotates.

[0027] Thus, in the proposed mechanical configuration, there is signal redundancy, with two magnetic signals provided by the action of the two outer gears and one inductive signal provided by the metallic rotor.

[0028] These different types of information signals imply new hardware configurations. Both mechanical and hardware configurations create "heterogeneous redundancies" for both signals.

[0029] The invention proposed herein presents a new mechanical configuration for fail-operational sensors, which reduces the sensor hysteresis and thereby provides improved overall sensor accuracy.

[0030] Another advantage of the fail-operational sensor principle is ensured through redundancy of all machine components. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] For a better understanding of the present application, figures illustrating preferred embodiments are attached herewith, which are not intended to limit the technology disclosed herein.

[0032] Figure 1 illustrates a new proposal and embodiment of a fail-operational steering angle sensor. Reference numbers refer to: 10 - Fail-operational steering angle sensor; 100 - cover; 110 - Printed Circuit Board (PCB); 120 - rotor; 130 - Hub; 140 - Gear B; 150 - Gear A; 160 - Housing.

[0033] 2 illustrates a possible embodiment of the proposed fail-operational steering angle sensor, in which new mechanical and electrical relationships between the sensor's components are depicted. Reference numbers refer to: 10 - Fail-operational steering angle sensor; 111 - PCB induction coil; 120 - rotor; 130 - Hub; 140 - Gear B.

[0034] Figure 3 illustrates the main mechanical elements of the proposed fail-operational steering angle sensor. Reference numbers refer to the following: 10 - Fail-operational steering angle sensor; 120 - rotor; 130 - Hub; 140 - Gear B (made of material B); 150 - Gear A (made of material A).

[0035] Figure 4 shows the actuator sensor of the fail-operational steering angle sensor (10). Reference numbers refer to the following: 120 - rotor; 121 - rotor gap; 130 - Hub; 131 - Hub drive key.

[0036] 5 illustrates the rotor (120) connection of the fail-operational steering angle sensor (10) to the steering wheel actuator shaft (125). Reference numbers refer to the following: 121 - rotor gap; 122 - rotor punch area; 123 - steering shaft keyway; 125 - SWA shaft.

[0037] 6 illustrates the connection of the housing (160) of the fail-operational steering angle sensor (10) to an external system. 160 - housing; 161 - Connector A; 162 - Connector B. DESCRIPTION OF EMBODIMENTS

[0038] Next, several embodiments will be described in more detail with reference to the figures, which are not intended to limit the scope of the present application. According to the illustration disclosed in Figure 1, an exploded view of the developed sensor 10 is shown. 1, the precise positioning and mechanical connections between all components can be seen. A set of internal mechanical and electrical components are arranged to interact with each other inside the housing (160), which is further closed by the cover (100).

[0039] The interior of the housing (160) contains internal components, including a flat, circular hub (130) with a set of outer teeth and a centrally located circular opening, aligned with the existing circular opening in the housing (160), which is also centrally located relative to the overall orientation of the housing (160). Both aligned central circular openings allow for mechanical traversal and contact with the SWA shaft (125) connected to the steering wheel, as suggested by the illustrated FIG. 5. A set of circular outer gears are mechanically coupled to the outer teeth of the hub (130), which are located on a set of circular outer gears. The set of circular outer gears also includes a set of outer teeth and a centrally located circular opening, and are gear A (150) and gear B (140). Both gears (140, 150) have a smaller diameter relative to the hub (130) and have teeth located on their outer edges that perfectly match the teeth of the hub (130).

[0040] Gear A (150) and Gear B (140) are made of two different materials and have different magnetic properties. Gear A (150) is made of magnetic material A, and Gear B (140) is made of magnetic material B. By using two different substrates for gears (140, 150), the system ensures two different failure mechanisms. For example, material A for gear A (150) has better mechanical performance, while material B for gear B (140) has better thermal performance.

[0041] That is, if the sensor is subjected to very severe thermal conditions, i.e., thermal swings, gear A (150) may fail, but the sensor will continue to operate with gear B (140) because gear B has better thermal performance. The same happens with mechanical loads: even if gear B (140) fails due to extreme loads, gear A (150) will withstand the failure and continue to operate because gear A has better mechanical performance. The key feature to ensure this behavior, which can withstand extreme external factors, is the selection of the most high-performance and appropriate materials for each gear.

[0042] In one proposed embodiment of the present invention, in a non-limiting manner, gear A (150) is made of a polymeric list with at least a magnetic pill therein, obtained via an overmolding method, and gear B (140) is made of a magnetic material therein. In the proposed embodiment, the materials used for both gears (140, 150) are not completely equal in terms of physical properties, but by using a combination of two completely different materials, it is possible to significantly reduce the possibility of failure of both gears (140, 150) at the same time.

[0043] The proposed material combination used for gear A (150) offers increased performance in terms of toughness and wear resistance, despite lower performance in terms of low operating temperatures, mechanical resistance, creep effects, and thermal expansion, whereas the proposed material combination used for gear B (140) has lower toughness and lower wear resistance, but can withstand high operating temperatures, has higher mechanical resistance, overcomes creep effects, and has lower thermal expansion.

[0044] In one possible embodiment of the present invention, the hub 130 rotates on a dedicated bearing arrangement. Gear A 150 and gear B 140 also rotate on dedicated bearing arrangements. The bearing arrangements for the hub 130, gear A 150, and gear B 140 are independent of each other and are defined by the housing 160.

[0045] In another preferred embodiment of the present invention, in a non-limiting arrangement, the hub 130 and both gears A 150 and B 140 are preferably arranged on the same rotational plane, with a circular rotor 120 having a set of protrusions disposed thereon. The rotor 120 has the same circular opening and diameter as described above, and the center of rotation of the rotor 120 coincides with the center of rotation of the hub 130. The rotor 120 is rigidly connected to the SWA shaft 125 and is mechanically aligned with and designed to rotate with the hub 130. This is achieved through a pre-existing rotor gap 121 along a circular opening extending along the inner wall of the rotor 120's circular opening. The rotor gap 121 coincides with a pre-existing hub drive key 131 disposed on the inner wall of the circular opening of the hub 130.

[0046] Because the hub (130) is a critical element for operating the gears (140, 150), in existing state-of-the-art steering angle sensors, failure of a particular part of the hub (130) results in failure of the entire sensor. In the mechanical arrangement of the fail-operational SAS (10) proposed herein, even if the hub (130) fails during operation, the rotor (120) maintains its movement / rotation activity in an independent manner, ensuring that there is still a signal supply from the steering.

[0047] In this particular case, if the hub (130) fails, the gears (140, 150) will no longer operate and the angle range of True Power On will no longer exist. However, the rotor (120) will still move / rotate and provide a rotation angle signal. Internal software is also configured to process and determine the number of rotations of the rotor (120) to ensure the supply of a steering wheel position signal. Even if the signal from the sensor (10) regresses / downgrades and True Power On is lost, it is still possible to safely park the vehicle or drive it to the nearest workshop in complete safety. The failure of the hub (130) does not compromise the operational safety of the vehicle.

[0048] Just as with the failure of the hub 130, the same thing happens if the rotor 120 fails. For the same reason, if the rotor 120 or the induction system consisting of the IC and coils fails, the hub 130 and gears 140, 150 will still function. The only detected backlash is related to a decrease in the accuracy of the sensor 10 output signal due to increased hysteresis. However, it is still possible to safely park the vehicle or drive it to the nearest work site in complete safety.

[0049] As shown in the representative images of the present invention, particularly in Figures 1, 3 and 4, both the rotor (120) and the hub (130) exhibit a disk-like shape. The rotor (120), whose disk-like surface rests on the hub (130), also comprises a set of apertures disposed along its surface.

[0050] A set of electrical components is disposed on the set of mechanical components, and the set of electrical components includes, for example, a printed circuit board (110).

[0051] In Figure 2, one possible position of the PCB (110) can be seen, centered on the plane formed by the hub (130), outer gears (140, 150), and rotor (120). The proposed PCB (110) includes a set of induction coils (111) evenly distributed on its surface. The PCB (110) is highlighted above the rotor (120) and is fitted and covered by the surface formed by the two overlapping disk-shaped hubs (130) and rotor (120) to determine these rotational process variations caused by a set of existing openings in the rotor (120) surface, as previously described. These coils (111), along with an additional IC precisely adapted and configured to operate with the PCB (110), are adapted to measure the magnetic flux variations induced by the rotor (120) movement.

[0052] The housing (160) is responsible for the location and alignment of all parts and internal components, and the cover (100) is responsible for ensuring the closure of the device.

[0053] In this newly developed mechanical configuration, the hub (130) includes a drive key (131). When the fail-operational steering angle sensor (10) is assembled, the hub's drive key (131) is also assembled to the keyway (123) of the SWA shaft (125). When the driver turns the vehicle's steering wheel, a mechanical connection is established with the fail-operational steering angle sensor (10) via the SWA shaft (125), not shown in the figure. This actuates the hub, further promoting the movement of the outer gears (140, 150) and the rotor (120). To ensure this mechanical connection, a larger gap (121) exists in the central circular opening of the rotor (120) than the hub's drive key (131).

[0054] In addition to the current mechanical actuation of the sensor 10 provided by the interaction between the steering shaft keyway 123 and the hub drive key 131, the rotor 120 is rigidly connected to the SWA shaft 125 simultaneously at three specific points 122 by a set of punches. The SWA shaft 125 has three recesses 122 located on the same plane and spaced 120° apart from one another. These recesses 122 are created by a specific tool during assembly of the sensor. This assembly deforms the outside of the circular opening of the rotor 120, which extends along the inner wall of the circular opening in the hub 130 and above said opening, against the recesses in the SWA shaft 125. This assembly creates a localized deformation of the rotor 120, ensuring a perfect fit of the rotor 120 to the SWA shaft 125. This feature ensures precise fixation between the parts minimizing the presence of gaps between the rotor (120) and the SWA shaft (125).

[0055] The use of a punched (122) rotor (120) relative to the SWA shaft (125) and the placement of the PCB (110) below the Cooper coil makes it possible to obtain a backlash-free induction system. This type of punched (122) connection is particularly important for reducing the sensor hysteresis, as previously mentioned. In the proposed configuration, gear play is preserved, but there is no slack between the rotor (120) and the SWA shaft (125). As a result, mechanical hysteresis does not affect the induction signal.

[0056] By using different types of connections between the sensor (10) and the SWA shaft (125), it is possible to separate the failure modes of the transmission. The hub (130) is connected by a drive key / keyway system (131), and the rotor (120) is connected to the SWA shaft (125) by a punch (122). Simply overmolding a portion of the rotor / hub is sufficient to operate the rotor (120) or hub (130), but there is only one connection to the shaft. If this connection fails, the entire sensor fails. The proposed mechanical arrangement of the present invention suppresses this failure and, by having two different types of connections, always has communication between the SWA shaft (125) and the sensor (10).

[0057] Inductive measurements, by design, can only measure a portion of the rotation of the SWA shaft (125). For example, if the rotor (120) has a set of four prongs / vanes, it can only measure four times 360° / 4 = 90°. This means that to have true power-on between both measurement systems, the number of vanes on the rotor (120) must be aligned with the number of teeth on the hub (130), gear A (150), and gear B (140). Both systems must have gear A (150) inductive, gear B (140) inductive, and gear A (150) aligned with gear B (140). This ensures true power-on for all, providing redundancy for three combinations with three respective vernier signals for how the angle is measured.

[0058] The vernier signal acts as a secondary auxiliary scale for the measuring instrument, improving measurement accuracy. For example, in a simple angle measuring instrument with one hub and one gear, if the hub has 50 teeth and the gear has 25 teeth, one rotation of the hub means two rotations of the gear. For example, if the system can read the gear with an accuracy of 1°, it means the instrument can read the hub with an accuracy of 0.5°. This improvement results in a narrower measurement range: the system now reads only 180° instead of the traditional 360°.

[0059] The disclosed invention aims to read not only the exact position of the steering wheel, but also its rotation speed. This means that only one gear cannot be used; two gears with different numbers of teeth must be used to accommodate misalignment of the gear rotation. This difference in tooth count allows for a long angular range, as the sensor's final angle is given by a clear position equation. For example, in a system with 70 teeth on the hub, 20 teeth on gear A, and 21 teeth on gear B, the sensor range is 2160°. After just six rotations, gears A and B will be in the exact same angular position, and the system will read the same value as at the start of the rotation.

[0060] In the disclosed arrangement of the fail-operational SAS (10), redundancy of angle information is ensured by three types of signal information (two magnetic and one inductive), resulting in three vernier signals: Vernier signal A is obtained by combining the magnetic angles resulting from gear A (150) and gear B (140); vernier signal B is obtained through a combination of the magnetic angle resulting from gear A (150) and the inductive angle resulting from rotor (120); and vernier signal C is obtained through a combination of the magnetic angle resulting from gear B (140) and the inductive angle resulting from rotor (120).

[0061] All three of these final angle information are true power-on, protecting against the possibility of sensor (10) failure. If an electrical or mechanical component fails, redundancy occurs through elimination, resulting in a downgrade of the signal, but ensuring the system continues to operate, even if only for a short period of time. Even if the system fails, the driver is not put at risk.

[0062] The redundant sensor output signal is a highly accurate inductive measurement ensured by the interaction of the rotor (120) protrusions with the induction coil (111) configured on the PCB (110). This inductive measurement must be combined with a magnetic measurement provided by an IC mounted on the PCB (110) positioned to detect variations in the magnetic field originating from the two outer gears A (150) and B (140). These two precision readings, inductive and magnetic, generated through the rotational motion of all mechanically interconnected components of the fail-operational SAS (10), cause different weightings for the angle calculation: one inductive for fine angle measurements, the other magnetic for wide-range measurements. These configurations must be configured via software adjustment of the inputs and outputs of both aforementioned signals to accommodate two different hysteresis levels.

[0063] In addition to the critical mechanical systems already mentioned above, the connection to the higher level decision system is ensured by two existing connectors (161, 162) in the sensor (10). These two connectors, connector A (161) and connector B (162), originate from and ensure redundancy of the information and signals passing through the sensor (10).

[0064] The use of a dual connection system to a higher-level determination system via two different connectors (161, 162) makes it possible to ensure the functionality of the sensor (10) even if something fails inside the sensor, i.e., if a connector pin in the PCB fails, or outside the sensor, i.e., if the male connector falls or the communication cable is cut. To achieve this level of redundancy, the signal emerging from connector A (161) must be the same as the signal emerging from connector B (162). In that case, the higher-level system receives duplicate information.

[0065] Separating both the mechanical and electrical connections to external devices, i.e., the hub / rotor (130, 120) connected to the SWA shaft (125) via two different punch areas (122) and drive keys (131), and the PCB (110) to a set of two independent connectors (161, 162) providing independent interfaces for communication and power supply, makes it possible to reduce the impact of failure of the sensor housing (160).

[0066] Failure of the housing (160) may affect the magnetic behavior of the gears (140, 150), but the induction rotor (120) remains operational. This also holds true for the reverse analysis and operation. This redundancy of physical features to ensure the operational state of the sensor (10) leads to improved performance and a reduced likelihood of overall failure.

[0067] This proposed arrangement allows the fail-operation SAS sensor (10) to have two types of measurements, inductive and magnetic, known as heterogeneous redundancy, which reduces the possibility of complete failure in the system. Apart from heterogeneous redundancy, the elimination of gaps and backlash in the inductive measurements allows for a significant improvement in the overall accuracy of the sensor (10) since there is no mechanical hysteresis between the SWA shaft (125) and the rotor (120).

[0068] It also increases the likelihood of reducing the nonlinearity of the sensor. To increase the overall accuracy of the sensor (10), the software needs to provide different heights when calculating the final output angle. The "fine" or "zoom" of the angle is provided by the guidance system, and the overall angle is provided by the combination of the guidance system and the magnetic system (gears). [Brief explanation of the drawings]

[0069] [Figure 1] A new proposal and embodiment of a fail-operational steering angle sensor is described. [Figure 2] A possible embodiment of the proposed fail-operational steering angle sensor is described, in which new mechanical and electrical relationships between the components of the sensor are presented. [Figure 3] The main mechanical elements of the proposed fail-operational steering angle sensor are described. [Figure 4] 1 shows the actuator sensor of the fail-operational steering angle sensor (10). [Figure 5] The rotor (120) connection of the fail-operational steering angle sensor (10) to the steering wheel actuator shaft (125) is now described. Reference numbers refer to the following: [Figure 6] The connection of the housing (160) of the fail-operational steering angle sensor (10) to an external system is now described.

Claims

1. a disc-shaped hub (130) with a central circular opening; at least two outer disk-shaped gears, Gear A (150) and Gear B (140), mechanically connected to the outer disk-shaped hub (130) by protruding teeth on the outer edges of the hub and the at least two outer disk-shaped gears; a printed circuit board (110) disposed on the disc-shaped hub (130) and the at least two disc-shaped outer gears; The disk-shaped hub (130) has a drive key (131) positioned in the central circular opening, and the drive key (131) mechanically engages the SWA shaft (125) through the central circular opening and mechanically engages the disk-shaped rotor (120) between the printed circuit board (110) and the disk-shaped hub (130).

2. 2. The fail-operational steering angle sensor for a vehicle of claim 1, wherein the SWA shaft facilitates direct rotational variation between the disk-shaped hub and the disk-shaped rotor and indirect, opposite rotational variation of the at least two disk-shaped outer gears due to their inherent contact points with the disk-shaped hub.

3. 3. The fail-operational steering angle sensor for a vehicle according to claim 1, wherein the printed circuit board is configured to determine rotational fluctuations of the disk-shaped hub, the disk-shaped rotor, and the at least two disk-shaped outer gears.

4. 4. The fail-operational steering angle sensor (10) for a vehicle according to claim 1, wherein the at least two outer disk-shaped gears have different diameters and different numbers of protruding teeth.

5. 5. The fail-operational steering angle sensor (10) for a vehicle according to claim 1, wherein the at least two outer disc-shaped gears have different material properties.

6. 6. The fail-operational steering angle sensor (10) for a vehicle according to claim 1, wherein the disc-shaped rotor (120) comprises a disc-shaped surface having a set of openings.

7. The disk-shaped rotor (120) has a central circular opening extending along an inner wall of the central circular opening of the disk-shaped hub (130) and extending above the central circular opening; 7. A fail-operational steering angle sensor for a vehicle as described in claim 1, wherein the disk-shaped rotor has a rotor gap that ensures mechanical alignment with the drive key located on the inner wall of the central circular opening of the disk-shaped hub.

8. 8. The fail-operational steering angle sensor for a vehicle (10) according to claim 7, wherein the rotor gap (121) mechanically aligns a steering shaft keyway (123) and a drive key (131) provided on the SWA shaft (125).

9. 9. The fail-operational steering angle sensor (10) for a vehicle according to claim 1, wherein the printed circuit board (110) has a set of induction coils (111) evenly arranged in a circular arrangement on its surface and precisely aligned with a set of openings in the disk-shaped rotor (120).

Images