Steering torque sensor midpoint correction device, method, and program

Abstract

To provide a middle point correction device, a method, and a program which can perform middle point correction without requiring any special device when no torque is applied to a steering shaft.SOLUTION: A middle point correction device 100 performs middle point correction of a steering torque sensor in a vehicle 102 including: an EPS device 12 for applying control torque to a steering transfer system 34 between a steering wheel 14 and steered wheels 16FL, 16FR; and a steering torque sensor 38 arranged in the steering transfer system. The middle point correction device includes: a non-volatile storage unit 50A; and a control unit 50 for performing a remote operation control of the vehicle. The control unit stores, when performing the remote operation control, steering torque Ts detected by the steering torque sensor as middle point offset amount Tsoff into the storage unit, reads out the middle point offset amount from the storage unit during traveling of the vehicle, and corrects the steering torque detected by the steering torque sensor by the middle point offset amount to perform the middle point correction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a neutral point correction device, method, and program for a steering torque sensor mounted on a vehicle such as an automobile.

Background Art

[0002] A steering torque sensor mounted on a vehicle such as an automobile detects the torque acting on a steering shaft or the like in a steering transmission system between a steering wheel and a steered wheel as the steering torque. The steering torque is used not only for controlling the assist torque of a power steering device but also for coordinated control between the driver's steering and driving support control. Therefore, it is necessary to accurately detect the steering torque by the steering torque sensor.

[0003] When no torque is acting on the steering shaft, the steering torque sensor outputs 0 indicating that the steering torque is 0, and when torque is acting on the steering shaft, it outputs a positive or negative value according to the direction and magnitude of the torque.

[0004] However, due to various external factors, even when no torque is acting on the steering shaft, the output of the steering torque sensor may not become 0, and a so-called neutral point (zero point) offset may occur. Therefore, it is known to perform neutral point correction of the steering torque sensor by obtaining the output of the steering torque sensor in a situation where it is estimated that no torque is acting on the steering shaft as the neutral point offset amount and correcting the output of the steering torque sensor by the neutral point offset amount.

[0005] For example, in Patent Document 1 below, the probability of neutral point detection is confirmed based on the variation in the detection value of the steering torque sensor when the ignition switch is turned off, and then the detection value of the steering torque sensor is used as the neutral point offset amount for neutral point correction.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2009-137514 [Overview of the project]

[0007] [Problems the invention aims to solve] However, when the ignition switch is turned off, it is not necessarily true that no torque is acting on the steering shaft. Furthermore, while it is known that a system can detect when no torque is acting on the steering shaft and perform a midpoint correction, special equipment such as a camera that films the driver is required to detect when no torque is acting on the steering shaft.

[0008] Incidentally, in vehicles capable of autonomous driving, remote driving, such as remote parking, may be performed, and this remote driving is carried out with the driver out of the vehicle. Therefore, when remote driving is in progress, no steering operations are performed by the driver, and no torque is applied to the steering shaft.

[0009] The present invention focuses on the fact that no torque acts on the steering shaft during remote driving, and provides a midpoint correction device, method, and program that can perform midpoint correction in a situation where no torque is acting on the steering shaft, without requiring any special equipment. [Means for solving the problem and the effects of the invention] According to the present invention, a steering torque sensor midpoint correction device (100) is provided, which is applied to a vehicle (102) equipped with a torque application device (EPS device 12) that applies control torque to a steering transmission system (34) between a steering wheel (14) and steering wheels (front wheels 16FL, 16FR), and a steering torque sensor (38) provided in the steering transmission system between the steering wheel and the torque application device, and is configured to perform midpoint correction of the steering torque sensor.

[0010] The midpoint correction device communicates with the terminal device (96) The driver is not in the vehicle.The vehicle includes a control unit (driver assistance ECU 50) that performs remote driving control of the vehicle, and the control unit is Store the midpoint offset amount (Tsoff) of the steering torque sensor. The steering torque (Ts) detected by the steering torque sensor in a situation where remote operation control is being performed, including a non-volatile memory device (50A) When the magnitude of the difference between the midpoint offset amount (Tsoff) stored in the memory exceeds the reference value (α), the steering torque detected by the steering torque sensor is Stored in memory This updates the midpoint offset amount. The system is configured to read the midpoint offset amount from a storage device while the vehicle is in motion, and to correct the steering torque detected by the steering torque sensor using the midpoint offset amount, thereby performing midpoint correction.

[0011] Furthermore, according to the present invention, a torque application device (EPS device 12) that applies control torque to the steering transmission system (34) between the steering wheel (14) and the steering wheels (front wheels 16FL, 16FR), and a steering torque sensor (38) provided in the steering transmission system between the steering wheel and the torque application device, A non-volatile memory device (50A) that stores the midpoint offset amount (Tsoff) of the steering torque sensor, A method for correcting the midpoint of a steering torque sensor is provided, which is applied to a vehicle (102) equipped with a steering torque sensor.

[0012] The midpoint correction method is performed by communicating with the terminal device (96) The driver is not in the vehicle. In situations where the vehicle is being remotely controlled, the steering torque (Ts) detected by the steering torque sensor When the magnitude of the difference between the midpoint offset amount (Tsoff) stored in the memory exceeds the reference value (α), the steering torque detected by the steering torque sensor is Stored in memory This updates the midpoint offset amount. The system includes the steps of (S10 to S50), reading the midpoint offset amount from a storage device while the vehicle is in motion (S110, S120), and correcting the steering torque detected by the steering torque sensor using the midpoint offset amount (S130).

[0013] Furthermore, according to the present invention, a torque application device (EPS device 12) that applies control torque to the steering transmission system (34) between the steering wheel (14) and the steering wheels (front wheels 16FL, 16FR), and a steering torque sensor (38) provided in the steering transmission system between the steering wheel and the torque application device, A non-volatile memory device (50A) that stores the midpoint offset amount (Tsoff) of the steering torque sensor,A steering torque sensor midpoint correction program is provided, which is applied to a vehicle (102) equipped with the steering torque sensor and causes an electronic control unit (driver assistance ECU 50) mounted on the vehicle to perform midpoint correction of the steering torque sensor.

[0014] The midpoint correction program communicates with the terminal device (96) The driver is not in the vehicle. In situations where the vehicle is being remotely controlled, the steering torque (Ts) detected by the steering torque sensor When the magnitude of the difference between the midpoint offset amount (Tsoff) stored in the memory exceeds the reference value (α), the steering torque detected by the steering torque sensor is Stored in memory This updates the midpoint offset amount. The system includes the steps of (S10 to S50), reading the midpoint offset amount from a storage device while the vehicle is in motion (S110, S120), and correcting the steering torque detected by the steering torque sensor using the midpoint offset amount (S130).

[0015] According to the above steering torque sensor midpoint correction device, method, and program, The driver is not in the vehicle. When the vehicle is under remote driving control, the steering torque detected by the steering torque sensor When the magnitude of the difference between the midpoint offset amount stored in the memory device exceeds the reference value, the steering torque detected by the steering torque sensor is Stored in memory This updates the midpoint offset amount. In situations where the vehicle is remotely controlled, the driver is out of the vehicle, so no torque acts on the steering transmission system and steering torque sensor. Therefore, the steering torque detected by the steering torque sensor in a situation where no torque is acting on the steering torque sensor is stored in a non-volatile memory as the precise midpoint offset amount of the steering torque sensor. The midpoint offset amount is updated to the correct value. It is possible.

[0016] Furthermore, when the vehicle is in motion, the midpoint offset amount is read from the storage device, and the steering torque detected by the steering torque sensor is corrected by the midpoint offset amount. Therefore, when the vehicle is in motion, the steering torque detected by the steering torque sensor can be corrected by the accurate midpoint offset amount.

[0017] Furthermore, the vehicle only needs to be capable of remote driving control, and there is no need for special devices to detect when no torque is acting on the steering shaft, such as a camera to film the driver. 〔Aspects of the Invention〕

[0018] In one aspect of the present invention, the control unit (operation support ECU 50) stores the steering torque (Ts) detected by the steering torque sensor (38) after applying vibration torque to the steering transmission system (34) by the torque application device (EPS device 12). When the magnitude of the difference between this value and the midpoint offset amount (Tsoff) stored in the memory exceeds the reference value (α), the steering torque detected by the steering torque sensor is in the storage device This updates the midpoint offset amount. (S20 ~ S50).

[0019] According to the above aspect, by applying vibration torque to the steering transmission system, the torque remaining in the steering transmission system is released, and then the steering torque detected by the steering torque sensor When the magnitude of the difference between the midpoint offset amount stored in the memory device exceeds the reference value, the steering torque detected by the steering torque sensor is is stored in the storage device This updates the midpoint offset amount. Therefore, compared with the case where vibration torque is not applied to the steering transmission system, the possibility that the neutral point offset amount is affected by the torque remaining in the steering transmission system is reduced, and the neutral point offset amount can be obtained more accurately , update the midpoint offset amount to a more accurate value. can be determined.

[0020] In another aspect of the present invention, the remote driving control includes at least one of remote parking control, automatic valet parking control, and smart summon control.

[0021] According to the above aspect, since the remote driving control includes at least one of remote parking control, automatic valet parking control, and smart summon control, an accurate neutral point offset amount of the steering torque sensor can be obtained when at least one of the controls is being performed.

[0022] In the above description, for the purpose of helping to understand the present invention, the names and / or symbols used in the embodiments corresponding to the configurations of the invention described later are added in parentheses. However, each component of the present invention is not limited to the components of the embodiments corresponding to the names and / or symbols added in parentheses. Other objects, other features, and accompanying advantages of the present invention will be easily understood from the description of the embodiments of the present invention described while referring to the following drawings. [Brief explanation of the drawing]

[0023] [Figure 1] This is a schematic diagram showing a steering torque sensor midpoint correction device according to an embodiment. [Figure 2] This is a flowchart showing the routine for detecting and controlling the midpoint offset amount in the first embodiment. [Figure 3] This is a flowchart showing the midpoint correction control routine in the first embodiment. [Figure 4] This is a flowchart showing the routine for detecting and controlling the midpoint offset amount in the second embodiment. [Figure 5] This is a flowchart showing the routine for detecting and controlling the midpoint offset amount in the third embodiment. [Modes for carrying out the invention]

[0024] Embodiments of the present invention will be described in detail below with reference to the attached figures.

[0025] As shown in Figure 1, the steering torque sensor midpoint correction device 100 according to this embodiment is applied to a vehicle 102 and includes a steering device 10, an electric power steering ECU 40, and a driver assistance ECU 50. The vehicle 102 may be an autonomous driving vehicle and includes a drive ECU 60, a brake ECU 70, and a meter ECU 80. In this specification, electric power steering is referred to as EPS (Electric Power Steering) as needed.

[0026] Each ECU, such as the EPS ECU40 and the driver assistance ECU50, is an Electronic Control Unit (ECCU) that primarily consists of a microcomputer and is connected to each other via a CAN (Controller Area Network) 104, enabling them to send and receive information. Each microcomputer includes a CPU, ROM, RAM, and interfaces. The CPU implements various functions by executing instructions (programs, routines) stored in the ROM. These ECUs may be integrated into a single ECU. In particular, the driver assistance ECU50 includes a read / write non-volatile memory device.

[0027] As shown in Figure 1, the steering system 10 includes an EPS device 12 connected to the EPS ECU 40, which is configured as a rack-and-pinion type EPS device driven in response to the driver's operation of the steering wheel 14. The rack bar 18 of the EPS device 12 is connected via tie rods 20L and 20R to the knuckle arms (not shown) of the steering wheels, the front wheels 16FL and 16FR. The steering wheel 14 is connected to the pinion shaft 26 of the EPS device 12 via a steering shaft 22 and a universal joint 24.

[0028] In the illustrated embodiment, the EPS device 12 is a rack-assist type electric power steering device and includes an electric motor 28 and a conversion mechanism 30, for example a belt type, which converts the rotation and torque of the electric motor 28 into reciprocating displacement and force and transmits it to the rack bar 18. The EPS device 12 generates control torque by driving the rack bar 18 relative to the housing 32.

[0029] Therefore, the steering shaft 22, universal joint 24, pinion shaft 26, EPS device 12, and tie rods 20L and 20R constitute a steering transmission system 34 that transmits steering displacement and torque between the steering wheel 14 and the front wheels 16FL and 16FR. The EPS device 12 functions as a torque application device that applies control torque to the steering shaft 22 of the steering transmission system 34.

[0030] The steering shaft 22 is equipped with a steering angle sensor 36 for detecting the steering angle θs, and the pinion shaft 26 is equipped with a steering torque sensor 38 for detecting the steering torque Ts. The steering angle θs and steering torque Ts are assumed to be positive when the vehicle 102 turns to the right due to the driver's steering operation. Therefore, the steering torque Ts is a positive value when the relative rotation of the member on the steering wheel 14 side and the member on the EPS device 12 side with respect to the torsion bar (not shown) of the steering torque sensor 38 corresponds to the rightward turning direction of the vehicle.

[0031] Furthermore, the EPS device 12 may be a pinion-assist type or column-assist type EPS device, as long as it can apply control torque to the steering transmission system 34. Also, the steering torque sensor 38 may be located at any position on the steering transmission system 34, as long as it is located closer to the steering wheel 14 than the EPS device 12.

[0032] The EPS / ECU 40 controls the steering assist torque and reduces the driver's steering burden by controlling the EPS device 12 in a manner known in the art, based on the steering torque Ts and vehicle speed V detected by the driving operation sensor 90 and vehicle condition sensor 92 described later. Furthermore, the EPS / ECU 40 can steer the front wheels 16FL and 16FR as needed by controlling the EPS device 12. Thus, the EPS / ECU 40 and the EPS device 12 function as an automatic steering system 42 that automatically steers the front wheels as needed.

[0033] The driver assistance ECU 50 is connected to a camera sensor 52 and a radar sensor 54. The camera sensor 52 and radar sensor 54 each include multiple camera devices and multiple radar devices, respectively. The camera sensor 52 and radar sensor 54 function as a target information acquisition device 56 that acquires information on targets at least in front of the vehicle 102. LiDAR (Light Detection And Ranging) may be used instead of or in addition to the radar sensor 54.

[0034] Furthermore, a setting control 58 is connected to the driver assistance ECU 50, and the setting control 58 is positioned to be operated by the driver. Although not shown in Figure 1, in this embodiment, the setting control 58 includes a remote operation switch.

[0035] The drive ECU 60 is connected to a drive unit 62, which accelerates the vehicle 102 by applying driving force to the drive wheels, not shown in Figure 1. Under normal circumstances, the drive ECU 60 controls the drive unit 62 so that the driving force generated by the drive unit 62 changes in accordance with the driver's driving operation, and when it receives a command signal from the driver assistance ECU 50, it controls the drive unit 62 based on the command signal.

[0036] The braking ECU 70 is connected to a braking device 72 that decelerates the vehicle 102 by applying braking force to the wheels, which are not shown in Figure 1. Under normal circumstances, the braking ECU 70 controls the braking device 72 so that the braking force generated by the braking device 72 changes in accordance with the driver's braking operation. When it receives a command signal from the steering support ECU 50, it performs automatic braking by controlling the braking device 72 based on the command signal.

[0037] The driving operation sensor 90 and the vehicle condition sensor 92 are connected to the CAN 104. Information detected by the driving operation sensor 90 and the vehicle condition sensor 92 (referred to as sensor information) is transmitted to the CAN 104. The driving operation sensor 90 includes a drive operation amount sensor and a brake operation amount sensor. The vehicle condition sensor 92 includes a vehicle speed sensor, a longitudinal acceleration sensor, a lateral acceleration sensor, and a yaw rate sensor, etc.

[0038] Furthermore, the transceiver 94 is connected to the CAN 104. The transceiver 94 communicates with a terminal device 96, such as a smartphone, via wireless communication such as Bluetooth (registered trademark) or internet communication. The driver assistance ECU 50 performs remote driving control by controlling the automatic steering system 42 to automatically steer the front wheels 16FL and 16FR, and by controlling the drive system 62 and braking system 72 to control the braking and driving force, based on commands input from the terminal device 96 via the transceiver 94.

[0039] The driver assistance ECU 50 is a central control unit that performs driver assistance controls such as remote driving control, steering torque sensor midpoint offset detection control, steering torque sensor midpoint correction control, and lane keeping control. In this embodiment, the driver assistance ECU 50 works in cooperation with the transceiver 94, the terminal device 96, and other ECUs to perform remote driving control when the remote driving switch is on and the remote driving control application of the terminal device 96 is activated.

[0040] The remote driving control may be at least one of the following: remote parking control, automatic valet parking control, and smart summon control, in which the driver or another user remotely controls the vehicle by operating the terminal device 96. Remote parking control is a control that parks the vehicle in a predetermined parking position and retrieves the vehicle from the parking position by remote control while the driver is out of the vehicle. Automatic valet parking control is a control that, in the case of a parking lot of a large facility, performs the handover of the vehicle, round trip to the parking position, parking, and retrieval by unmanned automatic driving, except when the user gets in and out of the vehicle at the entrance or exit. Smart summon control is a control that summons the vehicle by automatic driving to the driver's position or a designated position without the driver being in the vehicle. The remote driving control is not the essence of the present invention and may be performed in any manner known in the art.

[0041] Furthermore, when remote driving control is being performed, the driver assistance ECU 50 performs a midpoint offset detection control of the steering torque sensor, thereby storing the steering torque Ts detected by the steering torque sensor 38 as the midpoint offset Tsoff of the steering torque sensor in the storage device 50A. In addition, when the vehicle 102 is in motion, the driver assistance ECU 50 performs a midpoint correction by performing a midpoint correction control of the steering torque sensor, thereby correcting the steering torque Ts detected by the steering torque sensor 38 by the midpoint offset Tsoff.

[0042] [First Embodiment] In the first embodiment, the ROM of the steering assist ECU 50 stores a program for detecting the midpoint offset amount of the steering torque sensor and a program for correcting the midpoint of the steering torque sensor, corresponding to the flowcharts shown in Figures 2 and 3, respectively. The CPU executes the midpoint offset amount detection control and the midpoint correction control of the steering torque sensor according to these programs. <Midpoint offset amount detection control routine of the first embodiment>

[0043] The midpoint offset amount detection control, as shown in the flowchart in Figure 2, is repeatedly executed at predetermined intervals by the CPU of the driving support ECU 50 when the remote operation switch on the setting control unit 58 (not shown in Figure 1) is turned ON. Furthermore, at the start of the midpoint offset amount detection control, the count value N (an integer greater than or equal to 0), which indicates the number of midpoint offset amount detections described later, is reset to its initial value of 0. These procedures are also applicable to the midpoint offset amount detection control in other embodiments described later.

[0044] First, in step S10, the CPU determines whether or not remote driving control is in progress, that is, whether or not remote driving control, which controls automatic steering and braking / driving force, is being performed based on commands input from the terminal device 96 via the transceiver 94. The vehicle 102 may be in either a driving state or a stationary state. If a negative determination is made, step S10 is executed again, and if a positive determination is made, the control proceeds to step S30.

[0045] In step S30, the CPU reads the steering torque Ts detected by the steering torque sensor 38 from the EPS ECU 40 via CAN 104.

[0046] In step S40, the CPU determines whether or not it is necessary to update the midpoint offset amount Tsoff of the steering torque sensor. Specifically, with α as a positive constant, it is determined whether the absolute value of the steering torque Ts is smaller than the value obtained by subtracting α from the absolute value of the midpoint offset amount Tsoff stored in the memory device 50A, or whether it is larger than the sum of the absolute value of the midpoint offset amount Tsoff and α. If a negative determination is made, the control proceeds to step S60; if a positive determination is made, the control proceeds to step S50.

[0047] In step S50, the CPU stores the steering torque Ts as the midpoint offset amount Tsoff of the steering torque sensor in the memory device 50A.

[0048] In step S60, the CPU increments the count value N, which indicates the number of times the midpoint offset amount has been detected, by 1.

[0049] In step S70, the CPU determines whether the count value N is greater than or equal to a reference value Nc (for example, a positive integer such as 3). If the CPU determines that the count value N is greater than or equal to a reference value Nc, the control returns to step S10; if the CPU determines that the count value N is greater than or equal to a reference value Nc, the control terminates. <Midpoint correction control routine of the first embodiment>

[0050] The midpoint correction control according to the flowchart shown in Figure 3 is repeatedly executed at predetermined intervals by the CPU of the driver assistance ECU 50 when the ignition switch (not shown in Figure 1) is ON. Alternatively, the midpoint correction control according to the flowchart shown in Figure 3 may also be repeatedly executed at predetermined intervals by the CPU of the EPS ECU 40.

[0051] First, in step S110, the CPU determines whether or not remote driving control is in progress, similar to step S10. The vehicle 102 may be in either a driving state or a stationary state. If the determination is positive, this control is terminated; if the determination is negative, this control proceeds to step S120.

[0052] In step S120, the CPU reads the steering torque Ts detected by the steering torque sensor 38 from the EPS ECU 40 via CAN 104. Furthermore, the CPU reads the midpoint offset amount Tsoff from the storage device 50A.

[0053] In step S120, the CPU outputs the corrected steering torque Ts, which is the value Ts-Tsoff obtained by subtracting the midpoint offset amount Tsoff from the steering torque Ts. The corrected steering torque Ts may be used not only for controlling the steering assist torque but also for various driving assistance controls of the vehicle 102.

[0054] [Second Embodiment] In the second embodiment, the ROM of the steering assist ECU 50 stores a program for detecting the midpoint offset amount of the steering torque sensor and a program for correcting the midpoint of the steering torque sensor, corresponding to the flowcharts shown in Figures 4 and 3, respectively. The CPU executes the midpoint offset amount detection control and the midpoint correction control of the steering torque sensor according to these programs. The midpoint correction control of the steering torque sensor is the same as the midpoint correction control of the steering torque sensor in the first embodiment, so a description of this control is omitted. <Midpoint offset amount detection control routine of the second embodiment>

[0055] In the second embodiment, if a positive determination is made in step S10, the control proceeds to step S20. As can be seen from comparing Figure 4 and Figure 2, the steps other than step S20 are performed in the same manner as in the first embodiment.

[0056] In step S20, the CPU outputs a command signal to the EPS ECU 40, thereby applying vibration torque to the steering shaft 22 of the steering transmission system 34 via the EPS device 12. The vibration torque is such that it releases residual torque in the steering shaft caused by friction between the steering shaft 22 and the support device that rotatably supports it, and is not large enough to steer the front wheels 16FL and 16FR.

[0057] [Third Embodiment] In a third embodiment, although not shown in Figure 1, the camera sensor 52 includes a driver monitor camera that photographs the driver's seat from front to rear, in addition to a camera that photographs the area around the vehicle 102. Also, although not shown in Figure 1, the driving operation sensor 90 includes a touch sensor. The touch sensor is provided on the steering wheel 14 and detects whether the steering wheel is being held by the driver's hand.

[0058] Furthermore, in the third embodiment, the ROM of the steering assist ECU 50 stores a program for detecting the midpoint offset amount of the steering torque sensor and a program for correcting the midpoint of the steering torque sensor, corresponding to the flowcharts shown in Figures 5 and 3, respectively. The CPU executes the midpoint offset amount detection control and the midpoint correction control of the steering torque sensor according to these programs. The midpoint correction control of the steering torque sensor is the same as the midpoint correction control of the steering torque sensor in the first embodiment, so a description of this control is omitted. <Midpoint offset amount detection control routine of the third embodiment>

[0059] In the third embodiment, if a positive determination is made in step S10, the control proceeds to step S12. As can be seen from the comparison between Figure 5 and Figure 2, steps other than steps S12 and S14 are performed in the same manner as in the first embodiment.

[0060] In step S12, the CPU determines, based on the results of analyzing the images captured by the driver monitoring camera, whether or not the driver is in the vehicle 102 and seated in the driver's seat. If a negative determination is made, the control proceeds to step S30; if a positive determination is made, the control proceeds to step S14.

[0061] In step S14, the CPU determines whether the steering wheel 14 is being held by the driver's hand based on the detection result of the touch sensor. If the determination is positive, the control returns to step S10; if the determination is negative, the control proceeds to step S30.

[0062] As can be seen from the above explanation, according to each embodiment, The driver is not in the vehicle. In a situation where the vehicle is being remotely controlled (S10), the steering torque Ts detected by the steering torque sensor 38 When the magnitude of the difference between the midpoint offset amount Tsoff stored in the memory device exceeds the reference value α (S40), the steering torque detected by the steering torque sensor is Stored in memory This updates the midpoint offset amount. It will be done (S50)When the vehicle is being remotely controlled, the driver has left the vehicle, so no torque acts on the steering transmission system 34 and the steering torque sensor 38. Therefore, the steering torque detected by the steering torque sensor when no torque is acting on it is stored in a non-volatile memory device as the precise midpoint offset amount of the steering torque sensor. The midpoint offset amount is updated to the correct value. It is possible.

[0063] Furthermore, when the vehicle is in motion, the midpoint offset amount is read from the storage device, and the steering torque Ts detected by the steering torque sensor is corrected by the midpoint offset amount Tsoff. Therefore, when the vehicle is in motion, the steering torque detected by the steering torque sensor can be corrected with an accurate midpoint offset amount.

[0064] Furthermore, according to each embodiment, the remote driving control includes at least one of remote parking control, automatic valet parking control, and smart summon control, so the precise midpoint offset amount of the steering torque sensor 38 can be determined when at least one of these controls is being performed.

[0065] In particular, according to the first and second embodiments, the vehicle only needs to be a vehicle capable of remote driving control, and no special devices such as a camera to photograph the driver are required to detect when no torque is acting on the steering shaft 22.

[0066] Furthermore, according to the second embodiment, when vibration torque is applied to the steering transmission system 34, the torque remaining in the steering transmission system is released. (S20) Subsequently, the steering torque Ts detected by the steering torque sensor 38 When the magnitude of the difference between the midpoint offset amount Tsoff stored in the memory device 50A exceeds the reference value α, the steering torque detected by the steering torque sensor is Stored in memory This updates the midpoint offset amount. Therefore, compared to the case where no vibration torque is applied to the steering transmission system, the risk of the midpoint offset being adversely affected by the torque remaining in the steering transmission system is reduced, and the midpoint offset can be determined more accurately. , update the midpoint offset amount to a more accurate value. It is possible.

[0067] Although the present invention has been described in detail with respect to specific embodiments, it will be apparent to those skilled in the art that the present invention is not limited to the embodiments described above, and that various other embodiments are possible within the scope of the present invention.

[0068] For example, in each of the embodiments described above, in step S40, it is determined whether or not it is necessary to update the midpoint offset amount Tsoff of the steering torque sensor based on the steering torque Ts detected by the steering torque sensor 38 and read in step S30. However, the steering torque used for the determination in step S40 may be the average value of the steering torque Ts read in step S30 over a predetermined control cycle.

[0069] Furthermore, in the above-described embodiment, in step S60, the count value N, which indicates the number of times the midpoint offset amount has been detected, is incremented by 1. In step S70, it is determined whether the count value N is greater than or equal to the reference value Nc. If a negative determination is made, the control returns to step S10. However, steps S60 and S70 may be omitted, and steps S30 to S50 may be repeatedly executed while remote operation control is being performed.

[0070] In the second embodiment, in step S20, vibration torque is applied to the steering shaft 22 of the steering transmission system 34 by the EPS device 12, and then in step S30, the steering torque Ts detected by the steering torque sensor 38 is read. However, if a positive determination is made for the first time in step S10, step S20 is executed, and if a positive determination is made for the second time or later in step S10, step S20 may be skipped, and the control may proceed to step S30 without step S20 being executed.

[0071] In the third embodiment, if it is determined in step S12 that the driver is seated in the driver's seat, it is determined in step S14 whether or not the steering wheel 14 is being held by the driver's hands. If a negative determination is made, the control proceeds to step S30. However, either step S12 or S14 may be omitted. If step S14 is omitted, if an affirmative determination is made in step S12, the control returns to step S10; if a negative determination is made, the control proceeds to step S30.

[0072] Furthermore, in the third embodiment, step S20 is not performed. However, in the third embodiment, step S20 may also be performed. [Explanation of symbols]

[0073] 10...Steering system, 12...EPS system, 14...Steering wheel, 16FL, 16FR...Front wheels, 40...EPS ECU, 50...Driver assistance ECU, 50A...Memory device, 60...Drive ECU, 70...Braking ECU, 100...Midpoint correction device for steering torque sensor, 102...Vehicle

Claims

1. A steering torque sensor midpoint correction device is applied to a vehicle equipped with a torque application device that applies control torque to the steering transmission system between the steering wheel and the steering wheel, and a steering torque sensor provided in the steering transmission system between the steering wheel and the torque application device, and is configured to perform midpoint correction of the steering torque sensor, A steering torque sensor midpoint correction device is configured to perform midpoint correction by including a control unit that remotely controls the operation of a vehicle without a driver by communicating with a terminal device, the control unit including a non-volatile memory that stores the midpoint offset amount of the steering torque sensor, and when the difference between the steering torque detected by the steering torque sensor and the midpoint offset amount stored in the memory exceeds a reference value while the remote operation control is being performed, the steering torque detected by the steering torque sensor is stored in the memory to update the midpoint offset amount, the midpoint offset amount is read from the memory when the vehicle is running, and the steering torque detected by the steering torque sensor is corrected by the midpoint offset amount.

2. A steering torque sensor midpoint correction device according to claim 1, wherein the control unit is configured to update the midpoint offset amount by storing the steering torque detected by the steering torque sensor in the storage device when the magnitude of the difference between the steering torque detected by the steering torque sensor and the midpoint offset amount stored in the storage device exceeds a reference value after vibration torque has been applied to the steering transmission system by the torque application device.

3. A steering torque sensor midpoint correction device according to claim 1, wherein the remote driving control includes at least one of remote parking control, automatic valet parking control, and smart summon control.

4. A steering torque sensor midpoint correction method is applied to a vehicle comprising: a torque application device that applies control torque to the steering transmission system between the steering wheel and the steering wheel; a steering torque sensor provided in the steering transmission system between the steering wheel and the torque application device; and a non-volatile memory device that stores the midpoint offset amount of the steering torque sensor, and performs midpoint correction of the steering torque sensor. A steering torque sensor midpoint correction method, comprising the steps of: updating the midpoint offset amount by storing the steering torque detected by the steering torque sensor in the storage device when the difference between the steering torque detected by the steering torque sensor and the midpoint offset amount stored in the storage device exceeds a reference value in a situation where remote driving control of a vehicle without a driver is being performed by communicating with a terminal device; and reading the midpoint offset amount from the storage device when the vehicle is running, and correcting the steering torque detected by the steering torque sensor with the midpoint offset amount.

5. A steering torque sensor midpoint correction program is applied to a vehicle comprising: a torque application device that applies control torque to the steering transmission system between the steering wheel and the steering wheel; a steering torque sensor provided in the steering transmission system between the steering wheel and the torque application device; and a non-volatile memory device that stores the midpoint offset amount of the steering torque sensor, and causes an electronic control device mounted on the vehicle to perform midpoint correction of the steering torque sensor, A steering torque sensor midpoint correction program, which includes the steps of: updating the midpoint offset amount by storing the steering torque detected by the steering torque sensor in the storage device when the magnitude of the difference between the steering torque detected by the steering torque sensor and the midpoint offset amount stored in the storage device exceeds a reference value in a situation where remote driving control of a vehicle without a driver is being performed by communicating with a terminal device; and reading the midpoint offset amount from the storage device when the vehicle is running, and correcting the steering torque detected by the steering torque sensor with the midpoint offset amount.

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