Steering control system

Abstract

The present invention provides a steering control device that can generate appropriate steering reaction force in accordance with the actual vehicle operation. [Solution] The steering control device controls a steering system in which power transmission between the vehicle's steering wheels and the steering wheel is separated. The steering system includes a steering shaft that steers the steering wheels and a reaction force motor that generates a steering reaction force applied to the steering wheel. Based on the steering state of the steering wheel, the steering control device controls the reaction force torque command value T for controlling the reaction force motor. * The system includes a processing circuit that performs calculations. The processing circuit performs a first process and a second process. The first process calculates the deviation axial force as the axial force acting on the steering shaft, based on the steering angle ratio deviation Δγ, which is the difference between the target steering angle ratio that reflects the target state of the steering wheel and the estimated steering angle ratio that reflects the actual state of the steering wheel. The second process uses the calculated deviation axial force to calculate the reaction force torque command value T * This is a process that performs calculations.

Description

[Technical Field] 【0001】 This invention relates to a steering control device. [Background technology] 【0002】 Conventionally, steering systems using the so-called steer-by-wire system, which separates power transmission between the steering wheel and the steered wheels, are known. The steering system has a reaction motor and a steering motor. The reaction motor generates a steering reaction force applied to the steering shaft. The steering motor generates a steering force that turns the steered wheels. The steering control device controls the reaction motor and the steering motor according to the steering state of the steering wheel. 【0003】 For example, the steering control device described in Patent Document 1 calculates the converted steering angle by converting the actual steering angle to the steering wheel steering angle based on the reciprocal of the gear ratio. The steering angle is calculated based on the rotation angle of the steering motor. The gear ratio is the ratio of the steering angle to the steering angle and is calculated based on the actual steering angle and the vehicle speed. The steering control device controls the steering reaction force based on the steering angle deviation, which is the difference between the converted steering angle and the actual steering angle. [Prior art documents] [Patent Documents] 【0004】 [Patent Document 1] Japanese Patent Publication No. 2023-62515 [Overview of the Initiative] [Problems that the invention aims to solve] 【0005】 The steering control device described in Patent Document 1 has the following concerns: Specifically, depending on the responsiveness of the control system or mechanical system, the converted steering angle may not be calculated correctly. For example, the converted steering angle is affected by the response delay of the control system or mechanical system. Therefore, there are concerns that it may not be possible to generate an appropriate steering reaction force corresponding to the actual vehicle operation. [Means for solving the problem] 【0006】 A steering control device capable of solving the above problems is configured to control a steering device in which power transmission between the steering wheels of a vehicle and the steering wheel is separated, the steering device including a steering shaft configured to steer the steering wheels and a reaction motor configured to generate a steering reaction force to be applied to the steering wheel. The steering control device includes a processing circuit configured to calculate a reaction torque command value for controlling the reaction motor based on the steering state of the steering wheel. The processing circuit is configured to perform a first process and a second process. The first process is to calculate an axial force acting on the steering shaft based on the deviation between a first state variable reflecting a target state of the steering wheel and a second state variable reflecting the actual state of the steering wheel. The second process is to calculate the reaction torque command value using the calculated axial force. 【0007】 In this configuration, the axial force acting on the steering shaft is calculated based on the deviation between a first state variable, which reflects the target state of the steering wheel, and a second state variable, which reflects the actual state of the steering wheel. Therefore, the axial force can be said to reflect the actual vehicle state in which a deviation occurs between the target state and the actual state of the steering wheel. Consequently, by reflecting the axial force in the reaction torque command value, it is possible to generate an appropriate steering reaction force that corresponds to the actual vehicle operation. 【0008】 In the steering control device described above, the processing circuit is configured to further perform a third process. The third process is to calculate an assist torque command value, which is a torque in the same direction as the steering direction of the steering wheel, based on the steering state of the steering wheel. The first process includes a process of converting the calculated axial force into a torque applied to the steering wheel to calculate the axial force torque. The second process includes a process of calculating the reaction force command value by subtracting the axial force torque from the assist torque command value. 【0009】 This configuration allows for the generation of appropriate reaction torque command values ​​that reflect the actual vehicle conditions, where a deviation occurs between the target state and the actual state of the steering wheels. Therefore, it is possible to generate appropriate steering reaction forces that correspond to the actual vehicle operation. 【0010】 In the steering control device described above, the steering device has a shaft that rotates in conjunction with the steering wheel. The first state variable is a target steering angle ratio calculated based on the steering angle of the steering wheel. The second state variable is an estimated steering angle ratio estimated from the steering angle and the rotation angle of the shaft. 【0011】 As shown in this configuration, the target steering angle ratio is a state variable that reflects the target state of the steered wheel. The estimated steering angle ratio is a state variable that reflects the actual state of the steered wheel. Therefore, based on the deviation between the target steering angle ratio and the estimated steering angle ratio, it is possible to determine the axial force that reflects the actual vehicle state in which a deviation occurs between the target state and the actual state of the steered wheel. The steering angle ratio is the ratio of the steering angle of the steered wheel to the steering angle of the steering wheel. 【0012】 In the steering control device described above, the steering device includes a shaft that rotates in conjunction with the steering wheel, and a steering motor configured to generate a steering force applied to the steering shaft. The first state variable is a target rotation angle of the shaft calculated based on the steering angle of the steering wheel. The second state variable is a rotation angle of the shaft calculated based on the rotation angle of the steering motor. 【0013】 As shown in this configuration, the target rotation angle of the shaft is a state variable that reflects the target state of the steering wheel. The rotation angle of the shaft is a state variable that reflects the actual state of the steering wheel. Therefore, based on the deviation between the target steering angle ratio of the shaft and the rotation angle of the shaft, it is possible to determine the axial force that reflects the actual vehicle state in which a deviation occurs between the target state and the actual state of the steering wheel. 【0014】 In the steering control device described above, the first process includes a process of calculating the axial force using a map that defines the relationship between the deviation and the axial force. The characteristics of the map are set such that the absolute value of the axial force increases as the deviation increases. 【0015】 In this configuration, the absolute value of the axial force increases as the deviation increases. Therefore, as the deviation increases, the reaction torque command value, and consequently the steering reaction force, also increases. The driver of the vehicle can perceive the actual vehicle state in which a deviation occurs between the target state and the actual state of the steering wheels through the feel transmitted through the steering wheel. [Effects of the Invention] 【0016】 According to the steering control device of the present invention, it is possible to generate an appropriate steering reaction force in accordance with the actual vehicle operation. [Brief explanation of the drawing] 【0017】 [Figure 1] This is a diagram showing the configuration of a steering system on which the first embodiment of the steering control device is installed. [Figure 2] This is a block diagram of the reaction force control device and steering control device according to the first embodiment. [Figure 3] This is a block diagram of the deviation calculation unit according to the first embodiment. [Figure 4] This is a block diagram of the reaction force torque calculation unit according to the first embodiment. [Figure 5] This is a graph showing the deviation axial force map according to the first embodiment. [Figure 6] This is a block diagram of the deviation calculation unit according to the second embodiment. [Modes for carrying out the invention] 【0018】 <First Embodiment> The following describes a first embodiment of the steering control device. <Overall configuration of the steering control system> As shown in Figure 1, the steering control device 1 controls a steer-by-wire type steering device 2. The steering device 2 has a steering mechanism 3 and a steering mechanism 4. The steering mechanism 3 is a mechanism that is steered by the driver via the steering wheel 5. The steering mechanism 4 is a mechanism that steers the steering wheels 6 of the vehicle in response to the steering of the steering wheel 5. The steering control device 1 includes a reaction force control device 1A and a steering control device 1B. The reaction force control device 1A controls the steering mechanism 3. The steering control device 1B controls the steering mechanism 4. 【0019】 Depending on the product specifications, the reaction force control device 1A and the steering control device 1B may be integrated into a single steering control device 1. In this case, the reaction force control device 1A corresponds to the reaction force control unit, and the steering control device 1B corresponds to the steering control unit. 【0020】 The steering mechanism 3 includes a steering shaft 11, a reaction motor 12, and a reduction gear 13. The steering wheel 5 is rotatably connected to the steering shaft 11. The reaction motor 12 is the source of the steering reaction force applied to the steering shaft 11. The steering reaction force is a force in the opposite direction to the steering direction of the steering wheel 5. The reaction motor 12 is, for example, a three-phase brushless motor. The reduction gear 13 reduces the rotation of the reaction motor 12 and transmits the reduced rotation to the steering shaft 11. 【0021】 The steering mechanism 4 includes a pinion shaft 21, a steering shaft 22, and a housing 23. The housing 23 rotatably supports the pinion shaft 21. The housing 23 also reciprocates the steering shaft 22. Power transmission between the steering shaft 22 and the steering wheel 5 is isolated. The pinion shaft 21 is positioned to intersect the steering shaft 22. The pinion teeth 21a of the pinion shaft 21 mesh with the rack teeth 22a of the steering shaft 22. Tie rods 25 are connected to both ends of the steering shaft 22 via rack ends 24, which are ball joints. The ends of the tie rods 25 are connected to knuckles (not shown) to which the steering wheel 6 is assembled. 【0022】 The steering mechanism 4 comprises a steering motor 31, a transmission mechanism 32, and a conversion mechanism 33. The steering motor 31 is the source of the steering force applied to the steering shaft 22. The steering force is the force that causes the steering wheel 6 to turn. The steering motor 31 is, for example, a three-phase brushless motor. The transmission mechanism 32 is, for example, a belt drive mechanism. The transmission mechanism 32 transmits the rotation of the steering motor 31 to the conversion mechanism 33. The conversion mechanism 33 is, for example, a ball screw mechanism. The conversion mechanism 33 converts the rotation transmitted via the transmission mechanism 32 into axial motion of the steering shaft 22. 【0023】 As the steering shaft 22 moves axially, the steering angle θ of the steering wheel 6 changes. w The pinion teeth 21a of the pinion shaft 21 mesh with the rack teeth 22a of the steering shaft 22, and therefore rotate in conjunction with the movement of the steering shaft 22. The pinion shaft 21 is a shaft that rotates in conjunction with the steering action of the steering wheel 6. 【0024】 The reaction force control device 1A and the steering control device 1B each have a processing circuit that includes one of the following three configurations A1, A2, and A3. The processing circuit of the reaction force control device 1A is the first processing circuit, and the processing circuit of the steering control device 1B is the second processing circuit. 【0025】 A1. One or more processors that operate according to a computer program, which is software. A processor includes a CPU (Central Processing Unit) and memory. A2. One or more dedicated hardware circuits, such as application-specific integrated circuits (ASICs), that perform at least some of the various processes. An ASIC includes a CPU and memory. 【0026】 A3. A circuit combining configurations A1 and A2. Memory is a medium readable by a computer that stores programs describing processes or instructions for the computer. In this embodiment, the computer is the CPU. Memory includes RAM (Random Access Memory) and ROM (Read Only Memory). The CPU performs various controls by executing the programs stored in memory at predetermined calculation cycles. 【0027】 The reaction force control device 1A and the steering control device 1B each acquire detection results from on-board sensors. The reaction force control device 1A acquires detection results from, for example, the vehicle speed sensor 41, the torque sensor 42, and the first rotation angle sensor 43. The steering control device 1B acquires detection results from, for example, the second rotation angle sensor 44. 【0028】 The vehicle speed sensor 41 detects the vehicle speed V. The vehicle speed V is a state variable that reflects the vehicle's driving state. The torque sensor 42 is located on the steering shaft 11. The torque sensor 42 is positioned on the steering wheel 5 side relative to the connection portion of the reduction gear 13 on the steering shaft 11. The torque sensor 42 measures the steering torque T applied to the steering shaft 11. h It detects the steering torque T. h This is calculated based on the amount of twist of the torsion bar 42a provided on the steering shaft 11. Steering torque T h For example, this value is positive when the steering wheel 5 is steered to the right relative to the neutral position, and negative when the steering wheel 5 is steered to the left relative to the neutral position. The neutral position is the rotational position of the steering wheel 5 corresponding to the vehicle's straight-ahead state. Steering torque T h This is a state variable that reflects the steering state of the steering wheel 5. 【0029】 The first rotation angle sensor 43 is provided on the reaction motor 12. The first rotation angle sensor 43 measures the rotation angle θ of the reaction motor 12. a It detects. The second rotation angle sensor 44 is provided on the steering motor 31. The second rotation angle sensor 44 measures the rotation angle θ b of the steering motor 31. 【0030】 The reaction force control device 1A performs reaction force control. The reaction force control is control for generating a steering reaction force corresponding to the steering torque T h in the reaction force motor 12. The reaction force control device 1A controls the operation of the reaction force motor 12 using the detection results of the vehicle speed sensor 41, the torque sensor 42, and the first rotation angle sensor 43. The reaction force control device 1A controls the power supply to the reaction force motor 12 so as to generate a steering reaction force corresponding to the steering torque T h in the reaction force motor 12. 【0031】 The steering control device 1B performs steering control. The steering control is control for steering the steered wheels 6 according to the steering state of the steering wheel 5. The steering control device 1B controls the operation of the steering motor 31. The steering control device 1B controls the operation of the steering motor 31 using the detection result of the second rotation angle sensor 44. The steering control device 1B controls the power supply to the steering motor 31 so that the steered wheels 6 are steered according to the steering state of the steering wheel 5. 【0032】 <Configuration of Reaction Force Control Device 1A> Next, the configuration of the reaction force control device 1A will be described. As shown in FIG. 2, the reaction force control device 1A includes a steering angle calculation unit 51, a reaction force torque command value calculation unit 52, and a power supply control unit 53. 【0033】 The steering angle calculation unit 51 calculates the steering angle θ a of the steering wheel 5 based on the rotation angle θ s of the reaction force motor 12 detected by the first rotation angle sensor 43. The steering angle θ s is the rotation angle of the steering wheel 5 with respect to the neutral position of the steering wheel 5. The steering angle θ s is a state variable reflecting the steering state of the steering wheel 5. 【0034】 The reaction torque command value calculation unit 52 calculates the steering torque T h And based on the vehicle speed V, the reaction torque command value T * The reaction force torque command value T is calculated. * This is the target value of the steering reaction force generated by the reaction force motor 12. The steering reaction force is the torque in the opposite direction to the steering direction of the steering wheel 5. Steering torque T h The larger the absolute value of T, and the slower the vehicle speed V, the larger the reaction force torque command value T. * The absolute value of becomes larger. 【0035】 The energization control unit 53 controls the reaction force torque command value T. * The power supplied to the reaction motor 12 corresponds to the reaction torque command value T. Specifically, the power supply control unit 53 supplies power to the reaction torque command value T. * Based on this, the current command value for the reaction motor 12 is calculated. The current control unit 53 receives the current I generated in the power supply path via the current sensor 54 provided in the power supply path for the reaction motor 12. a The value of current I is detected. a The value of is the value of the current supplied to the reaction motor 12. The energization control unit 53 controls the current command value and current I a The deviation from the value is calculated, and the power supply to the reaction motor 12 is controlled to eliminate the deviation. As a result, the reaction motor 12 controls the reaction torque command value T * It generates torque corresponding to the value. 【0036】 <Configuration of steering control device 1B> Next, the configuration of the steering control device 1B will be described. As shown in Figure 2, the steering control device 1B includes a pinion angle calculation unit 61, a rudder angle ratio calculation unit 62, a target pinion angle calculation unit 63, a pinion angle feedback control unit 64, and an energization control unit 65. 【0037】 The pinion angle calculation unit 61 calculates the rotation angle θ of the steering motor 31 detected by the first rotation angle sensor 43. b Based on this, the pinion angle θ p The calculation is performed. Pinion angle θ pThis is the rotation angle of the pinion shaft 21, and corresponds to the actual angle of the pinion shaft 21. 【0038】 The steering motor 31 and the pinion shaft 21 are linked via the transmission mechanism 32, the conversion mechanism 33, and the steering shaft 22. Therefore, the rotation angle θ of the steering motor 31 b and pinion angle θ p There is a correlation between this and the rotation angle θ of the steering motor 31. b From the pinion angle θ p This can be determined. Also, the pinion shaft 21 meshes with the steering shaft 22. Therefore, the pinion angle θ p There is also a correlation between this and the amount of movement of the steering shaft 22. (Pinion angle θ) p The steering angle θ of the steering wheel 6. w In other words, it is a state variable that reflects the steering state of the steering wheel 6. 【0039】 The steering angle ratio calculation unit 62 calculates the steering angle θ calculated by the steering angle calculation unit 51. s The steering angle ratio calculation unit 62 takes in the steering angle θ. s Based on this, the target steering angle ratio γ is calculated. The target steering angle ratio γ is equal to the steering angle θ s The steering angle θ relative to this angle w This is the target value of the ratio. However, in this embodiment, the steering angle θ s The pinion angle θ relative to this angle p The ratio of θ is used as the target rudder angle ratio γ. p The steering angle θ is w This is a state variable that reflects the following. The target rudder angle ratio γ is expressed by the following equation (1). 【0040】 γ = θ p / θ s …(1) The steering angle ratio calculation unit 62 calculates the target steering angle ratio γ using, for example, a steering angle ratio map. The steering angle ratio is calculated using the steering angle θ. s A two-dimensional map may be used to define the relationship between the steering angle θ and the target steering angle ratio γ. s As the absolute value of increases, the target rudder angle ratio γ decreases. Conversely, the steering angle θ sAs the absolute value of decreases, the target steering angle ratio γ increases. Also, the steering angle ratio map is adjusted according to the steering angle θ in relation to the vehicle speed V. s This may be a three-dimensional map that defines the relationship between the vehicle speed V and the target steering angle ratio γ. The vehicle speed V is detected by the vehicle speed sensor 41. As the vehicle speed V increases, the target steering angle ratio γ increases. Conversely, as the vehicle speed V decreases, the target steering angle ratio γ decreases. 【0041】 The larger the target steering angle ratio γ, the greater the steering angle θ of the steering wheels 6 when the steering wheel 5 is operated. w The steering becomes smaller and slower. When changing lanes while driving straight, the amount of vehicle turning is suppressed to a small degree relative to the amount of steering wheel 5 is turned, thus ensuring the vehicle's handling stability. In addition, the smaller the target steering angle ratio γ, the smaller the steering angle θ of the steering wheels 6 when the steering wheel 5 is operated. w This makes the vehicle much more agile (quick). When parking or performing other maneuvers, a larger vehicle turning range is obtained relative to the steering input of the steering wheel 5, thus ensuring better vehicle handling. The target steering angle ratio γ corresponds to the first state variable, which reflects the target state of the steering wheels 6. 【0042】 The target pinion angle calculation unit 63 calculates the steering angle θ calculated by the steering angle calculation unit 51. s The target rudder angle ratio γ calculated by the rudder angle ratio calculation unit 62 is then taken in. The target pinion angle calculation unit 63 takes the steering angle θ s Based on the target rudder angle ratio γ, the target pinion angle θ p * The target pinion angle θ is calculated. p * The pinion angle θ is p This is the target angle. The target pinion angle calculation unit 63 calculates the target pinion angle θ so that the target steering angle ratio γ is achieved. p * Perform the calculation. 【0043】 The target pinion angle calculation unit 63 calculates the steering angle θ, for example, as shown in equation (2) below. s Multiply by the target rudder angle ratio γ to get the target pinion angle θ p *Perform the calculation. The "·" in equation (2) indicates multiplication. θ p * =θ s ·γ …(2) The pinion angle feedback control unit 64 receives the target pinion angle θ calculated by the target pinion angle calculation unit 63. p * The pinion angle θ is calculated by the pinion angle calculation unit 61. p The pinion angle feedback control unit 64 takes in the pinion angle θ. p The target pinion angle θ p * To follow this, the pinion angle θ p Through feedback control, the steering torque command value T p * The steering torque command value T is calculated. p * This is a command value for the torque generated by the steering motor 31, and is the target value for the steering force. 【0044】 The energization control unit 65 controls the steering torque command value T p * The power supply control unit 65 supplies power to the steering motor 31 according to the steering torque command value T. p * Based on this, the current command value for the steering motor 31 is calculated. The power supply control unit 65 receives the current I generated in the power supply path via the current sensor 66 provided in the power supply path to the steering motor 31. b The value of current I is detected. b The value of is the value of the current supplied to the steering motor 31. The energization control unit 65 controls the current command value and current I b The deviation from the value is calculated, and the power supply to the steering motor 31 is controlled to eliminate the deviation. As a result, the steering motor 31 controls the steering torque command value T p * It generates torque corresponding to the value. 【0045】 <Deviation Calculation Unit> The actual steering state of the steering wheel 6 is not determined only by the target steering angle ratio γ. The steering state of the steering wheel 6 is affected by, for example, a control system including the steering control device 1B, a mechanical system including the steering mechanism 4, or the responsiveness of the steering motor 31. Due to the influence of this responsiveness, there is a possibility that a deviation may occur between the target state and the actual state of the steering wheel 6. Therefore, the steering control device 1 adopts the following configuration in order to generate an appropriate steering reaction force according to the actual vehicle motion in which a deviation occurs between the target state and the actual state of the steering wheel 6, including the influence of responsiveness. 【0046】 As shown in FIG. 2, the steering control device 1B has a deviation calculation unit 67. The deviation calculation unit 67 takes in the steering angle θ calculated by the steering angle calculation unit 51 s and the pinion angle θ calculated by the pinion angle calculation unit 61 p and the target steering angle ratio γ calculated by the steering angle ratio calculation unit 62. The deviation calculation unit 67 calculates a steering angle ratio deviation Δγ based on the steering angle θ s , the pinion angle θ p , and the target steering angle ratio γ. 【0047】 As shown in FIG. 3, the deviation calculation unit 67 has an estimated steering angle ratio calculation unit 67A and a subtractor 67B. The estimated steering angle ratio calculation unit 67A calculates an estimated steering angle ratio γ^ based on, for example, the previous formula (1), using the steering angle θ s and the pinion angle θ p . The estimated steering angle ratio γ^ is a steering angle ratio estimated from the steering angle θ s and the pinion angle θ p and corresponds to a second state variable reflecting the actual state of the steering wheel 6. The subtractor 67B calculates the steering angle ratio deviation Δγ by subtracting the estimated steering angle ratio γ^ from the target steering angle ratio γ. 【0048】 Note that the estimated steering angle ratio calculation unit 67A may multiply the steering angle ratio deviation Δγ by a gain corresponding to the vehicle speed V to calculate the final steering angle ratio deviation Δγ used in the calculation of the reaction torque command value T * . <Reaction Torque Command Value Calculation Unit> Next, the configuration of the reaction force torque command value calculation unit 52 will be described. 【0049】 As shown in Figure 4, the reaction torque command value calculation unit 52 includes an assist torque command value calculation unit 81, an axial force calculation unit 82, and a subtractor 83. The assist torque command value calculation unit 81 calculates the steering torque T detected by the torque sensor 42. h The system also incorporates the vehicle speed V detected by the vehicle speed sensor 41. The assist torque command value calculation unit 81 calculates the assist torque command value T1 based on the steering torque Th and the vehicle speed V. The assist torque command value T1 corresponds to the target value of the assist torque when the steering device 2 is an electric power steering device. Assist torque is the force that assists in steering the steering wheel 5. The assist torque command value T1 is the torque in the same direction as the steering direction of the steering wheel 5. The larger the absolute value of the steering torque Th and the slower the vehicle speed V, the larger the absolute value of the assist torque command value T1. 【0050】 The axial force calculation unit 82 receives the steering angle ratio deviation Δγ calculated by the deviation calculation unit 67. Based on the steering angle ratio deviation Δγ, the axial force calculation unit 82 calculates the axial force acting on the steering shaft 22. The axial force calculation unit 82 calculates the axial force torque T2 by converting the calculated axial force into torque relative to the steering shaft 11. 【0051】 As shown in Figure 5, the axial force calculation unit 82 calculates the deviation axial force F0 using, for example, a first deviation axial force map M1 stored in memory. The first deviation axial force map M1 is a two-dimensional map that defines the relationship between the rudder angle ratio deviation Δγ and the deviation axial force F0. The first deviation axial force map M1 has, for example, the following characteristics: as the rudder angle ratio deviation Δγ increases, the absolute value of the deviation axial force F0 increases. 【0052】 As shown in FIG. 4, the subtractor 83 takes in the assist torque command value T1 calculated by the assist torque command value calculation unit 81 and the axial force torque T2 calculated by the axial force calculation unit 82. The subtractor 83 subtracts the axial force torque T2 from the assist torque command value T1 to calculate the reaction torque command value T * thereby. 【0053】 <Operation of the First Embodiment> Next, the operation of the first embodiment will be described. The rudder angle ratio deviation Δγ is the target relationship between the steering angle θ s corresponding to the target rudder angle ratio γ and the turning angle θ w and the actual relationship between the steering angle θ s corresponding to the estimated rudder angle ratio γ^ and the turning angle θ w reflects the deviation. Therefore, the deviation axial force F0 calculated based on the rudder angle ratio deviation Δγ can be said to be, for example, an axial force considering the influence of the control system including the turning control device 1B, the mechanical system including the turning mechanism 4, or the responsiveness of the turning motor 31. That is, it can be said that the deviation axial force F0 is an axial force that reflects the actual vehicle state in which a deviation occurs between the target state and the actual state of the turning wheel 6, including the influence of responsiveness. Therefore, by reflecting the deviation axial force F0 in the reaction torque command value T * it is possible to generate an appropriate steering reaction force according to the actual vehicle state in which a deviation occurs between the target state and the actual state of the turning wheel 6, including the influence of responsiveness. The vehicle state includes the turning state of the turning wheel 6. 【0054】 The driver of the vehicle can recognize the actual vehicle state in which a deviation occurs between the target state and the actual state of the turning wheel 6, including the influence of responsiveness, by the feel through the steering wheel 5. A deviation between the target state and the actual state of the turning wheel 6 occurs, for example, when the turning of the turning wheel 6 does not follow the steering of the steering wheel 5. 【0055】 <Effect of the First Embodiment> According to the first embodiment, the following effects can be obtained. (1-1) The steering control device 1 controls the reaction torque command value T for the reaction motor 12 based on the steering state of the steering wheel 5. * The system includes a processing circuit for calculating the reaction force torque command value. The reaction force torque command value calculation unit 52 corresponds to the processing circuit. The processing circuit performs a first process and a second process. The first process is to calculate the deviation axial force F0 as an axial force acting on the steering shaft 22 based on the steering angle ratio deviation Δγ, which is the deviation between the target steering angle ratio γ and the estimated steering angle ratio γ^. The second process uses the deviation axial force F0 to calculate the reaction force torque command value T * This is a process that performs calculations. 【0056】 In this configuration, the deviation axial force F0 acting on the steering shaft 22 is calculated based on the steering angle ratio deviation Δγ, which is the difference between the target steering angle ratio γ that reflects the target state of the steering wheel 6 and the estimated steering angle ratio γ^ that reflects the actual state of the steering wheel 6. The deviation axial force F0 is an axial force that reflects the actual vehicle state in which a deviation occurs between the target state and the actual state of the steering wheel 6, including the effect of responsiveness. Therefore, the deviation axial force F0 is used as the reaction torque command value T * By incorporating this into the system, it becomes possible to generate appropriate steering feedback force that corresponds to the actual vehicle's movement. Furthermore, the driver will not experience any discomfort such as a feeling of sticking or resistance. 【0057】 (1-2) The processing circuit further performs a third process. The third process is to calculate an assist torque command value T1, which is a torque in the same direction as the steering direction of the steering wheel 5, based on the steering state of the steering wheel 5. Steering torque T h This is a state variable that reflects the steering state of the steering wheel 5. The first process described above includes the process of converting the deviation axial force F0 into torque applied to the steering wheel 5 and calculating the axial force torque T2. The second process described above subtracts the axial force torque T2 from the assist torque command value T1 to obtain the reaction force torque command value T * This includes a process for calculating the appropriate reaction torque command value T, which reflects the actual vehicle conditions in which a deviation occurs between the target state and the actual state of the steering wheel 6, including the effects of responsiveness. *Therefore, the reaction torque command value T is obtained. * By controlling the reaction motor 12 based on this, it is possible to generate an appropriate steering reaction force that corresponds to the actual vehicle operation. 【0058】 (1-3) The steering device 2 has a shaft that rotates in conjunction with the steering wheel 6. The pinion shaft 21 is a shaft that rotates in conjunction with the steering wheel 6. The target steering angle ratio γ as the first state variable is a state variable that reflects the target state of the steering wheel 6, and the steering angle θ of the steering wheel 5 s It is calculated based on the following. The estimated rudder angle ratio γ^ as the second state variable is a state variable that reflects the actual state of the steering wheel 6, where the steering angle θ s This is estimated from the rotation angle of the pinion shaft 21. Therefore, based on the deviation between the target steering angle ratio γ and the estimated steering angle ratio γ^, it is possible to obtain an axial force that reflects the actual vehicle condition in which a deviation occurs between the target state and the actual state of the steering wheel 6, including the effect of responsiveness. 【0059】 (1-4) The first process described above includes a process of calculating the deviation axial force F0 using a first deviation axial force map M1 that defines the relationship between the steering angle ratio deviation Δγ and the deviation axial force F0. The characteristics of the first deviation axial force map M1 are set such that the absolute value of the deviation axial force F0 increases as the steering angle ratio deviation Δγ increases. With this configuration, the absolute value of the deviation axial force F0 increases as the steering angle ratio deviation Δγ increases. For this reason, as the steering angle ratio deviation Δγ increases, the reaction force torque command value T * Consequently, the steering reaction force increases. The driver of the vehicle can appropriately recognize the actual vehicle state in which a deviation occurs between the target state and the actual state of the steering wheels 6, including the effect of responsiveness, through the feedback transmitted via the steering wheel 5. 【0060】 <Second Embodiment> Next, a second embodiment of the steering control device 1 will be described. This embodiment has basically the same configuration as the first embodiment shown in Figures 1 to 4, but the configuration of the deviation calculation unit 67 differs from that of the first embodiment. Therefore, the same reference numerals are used for the same components and components as in the first embodiment, and their detailed descriptions are omitted. 【0061】 The target rudder angle ratio γ can be expressed, for example, as shown in equation (3) below. γ = 1 + α …(3) However, "1" is the base rudder angle ratio. "α" is, for example, the steering angle θ. s These are the settings that are configured accordingly. 【0062】 Applying equation (3) to equation (2) and expanding it yields equation (4). θ p * =θ s (1+α)=θ s +θ s ·α = …(4) However, "θ" p * "θ" is the target pinion angle. s " is the steering angle. "α" is, for example, the steering angle θ. s This is a setting value that is set according to the following: "θ s ·α" represents the steering angle θ s The addition angle β is added to it. tgt The addition angle β is such that... tgt The steering angle θ is s This is the correction angle for [the specified value]. 【0063】 The "θ" in equation (4) s ·α" to "β tgt Substituting this with the following equation (5), we obtain: θ p * =θ s +β tgt …(5) The target pinion angle calculation unit 63 calculates the target pinion angle θ based on equation (5). p *The calculation may also be performed by the target pinion angle calculation unit 63, which calculates the target rudder angle ratio γ calculated by the rudder angle ratio calculation unit 62, and the addition angle β. tgt The calculation is performed, and the calculated addition angle β tgt steering angle θ s This is added to the target pinion angle θ corresponding to the target rudder angle ratio γ. p * This can be obtained. 【0064】 Actual pinion angle θ p The target pinion angle θ is p * Similarly, it can be expressed as shown in equation (6) below. θ p =θ s +β real …(6) However, "β real " is the steering angle θ s This is the addition angle that is added to it. 【0065】 Transforming equation (6) yields equation (7), and transforming equation (5) yields equation (8). β real =θ p -θ s …(7) β tgt =θ p * -θ s …(8) Addition angle β in equation (8) tgt and the addition angle β in equation (7) real The added angle deviation Δβ, which is the deviation from the rudder angle ratio deviation Δγ, corresponds to the rudder angle ratio deviation Δγ mentioned earlier. The added angle deviation Δβ can be expressed as shown in equation (9) below. 【0066】 Δβ = β tgt -β real …(9) Expanding equation (9) by applying equations (7) and (8) yields equation (10). Δβ=(θ p * -θ s )-(θ p -θ s )=θ p* -θ p =Δθ p …(10) However, "Δθ p " is the target pinion angle θ p * and pinion angle θ p This is the pinion angle deviation, which is the difference from the given value. 【0067】 Note that in the calculations of equations (1) to (10), "θ" p * " is the target pinion angle θ p * The absolute value of, "θ" p " is the pinion angle θ p The absolute value of, "θ" s " is the steering angle θ s It is the absolute value of the target pinion angle θ. p * This corresponds to the first state variable that reflects the target state of the steering wheel 6, and the pinion angle θ p This corresponds to a second state variable that reflects the actual state of the steering wheel 6. 【0068】 As shown in Figure 6, the deviation calculation unit 67 utilizes the relationship shown in equation (10). The deviation calculation unit 67 calculates the target pinion angle θ calculated by the target pinion angle calculation unit 63. p * The pinion angle θ is calculated by the pinion angle calculation unit 61. p The deviation calculation unit 67 takes in the target pinion angle θ that is taken in. p * and pinion angle θ p Based on this, the pinion angle deviation Δθ p The calculation is performed. Although not shown in the diagram, the deviation calculation unit 67 has a subtractor. The subtractor has a target pinion angle θ. p * From the absolute value of the pinion angle θ p By subtracting the absolute value of Δθ, the pinion angle deviation is obtained. p Perform the calculation. 【0069】 As shown in Figure 4, the axial force calculation unit 82 calculates the pinion angle deviation Δθ calculated by the deviation calculation unit 67. pThe axial force calculation unit 82 takes in the pinion angle deviation Δθ. p Based on this, the axial force acting on the steering shaft 22 is calculated. The axial force calculation unit 82 calculates the axial force torque T2 by converting the calculated axial force into torque relative to the steering shaft 11. 【0070】 As shown in Figure 5, the axial force calculation unit 82 calculates the deviation axial force F0 using, for example, a second deviation axial force map M2 stored in memory. The second deviation axial force map M2 is the pinion angle deviation Δθ p This is a two-dimensional map that defines the relationship between the pinion angle deviation Δθ and the axial deviation force F0. The second axial deviation force map M2 has the following characteristics: p As the absolute value of increases, the absolute value of the axial force F0 also increases. 【0071】 As shown in Figure 4, the subtractor 83 takes in the assist torque command value T1 calculated by the assist torque command value calculation unit 81 and the axial force torque T2 calculated by the axial force calculation unit 82. The subtractor 83 subtracts the axial force torque T2 from the assist torque command value T1 to obtain the reaction force torque command value T * Perform the calculation. 【0072】 <Operation of the second embodiment> Next, the operation of the second embodiment will be described. The summation angle deviation Δβ corresponds to the rudder angle ratio deviation Δγ mentioned earlier. Also, as shown in equation (10) above, the summation angle deviation Δβ is equal to the pinion angle deviation Δθ p It can be expressed as follows. Therefore, the pinion angle deviation Δθ p The deviation axial force F0 calculated based on the above can be said to be an axial force that takes into account the influence of the control system including the steering control device 1B, the mechanical system including the steering mechanism 4, or the responsiveness of the steering motor 31, similar to the deviation axial force F0 calculated based on the steering angle ratio deviation Δγ. That is, the pinion angle deviation Δθ p The deviation axial force F0 calculated based on this can be said to be an axial force that reflects the actual vehicle state in which a deviation occurs between the target state and the actual state of the steering wheel 6, including the effect of responsiveness. Therefore, the pinion angle deviation Δθp The deviation axial force F0 calculated based on the reaction torque command value T * By reflecting this, it is possible to generate an appropriate steering reaction force that corresponds to the actual vehicle condition, including the effect of responsiveness, resulting in a deviation between the target state and the actual state of the steering wheel 6. The vehicle condition includes the steering state of the steering wheel 6. 【0073】 The driver of the vehicle can perceive the actual vehicle state, including the effect of responsiveness, as a deviation occurs between the target state and the actual state of the steering wheels 6 through the feedback received via the steering wheel 5. This deviation between the target state and the actual state of the steering wheels 6 occurs, for example, when the steering of the steering wheels 6 does not follow the steering input of the steering wheel 5. 【0074】 Note that the addition angle β shown in equation (7) above is also shown. real This can result in a negative value. This is because the pinion angle θ p The steering angle θ s This indicates that it has not reached the sum of the β values. In other words, the sum of the β values ​​has not been reached. real If the value is negative, it is considered that the steering response has decreased more than expected. Steering response is related to, for example, the pinion angle θ. p The target pinion angle θ p * This performance indicates how well it can keep up with the given conditions. Therefore, the addition angle β real Whether the value is positive or negative makes it possible to determine whether steering responsiveness has decreased. 【0075】 Therefore, the steering control device 1, for example, uses the summing angle β as information to switch to control for ensuring steering followability. real This may be used. Control to ensure steering response includes, for example, control of switching the feedback gain of the pinion angle feedback control unit 64. By adjusting the feedback gain, the pinion angle θ p The target pinion angle θ p * It is possible to reduce the time to reach this point. Control to ensure steering response may include switching between various maps. 【0076】 <Effects of the second embodiment> According to the second embodiment, the following effects are achieved. (2-1) The steering control device 1 controls the reaction force motor 12 based on the steering state of the steering wheel 5 by providing a reaction force torque command value T * It includes a processing circuit that calculates the reaction force torque command value. The reaction force torque command value calculation unit 52 corresponds to the processing circuit. The processing circuit performs a first process and a second process. The first process is the target pinion angle θ p * and pinion angle θ p The pinion angle deviation Δθ is the deviation from the given value. p The first step is to calculate the deviation axial force F0 as the axial force acting on the steering shaft 22 based on the above. The second step is to use the deviation axial force F0 to calculate the reaction torque command value T * This is a process that performs calculations. 【0077】 According to this configuration, the target pinion angle θ reflects the target state of the steering wheel 6. p * And the pinion angle θ reflects the actual state of the steering wheel 6. p The pinion angle deviation Δθ is the deviation from the given value. p Based on this, the deviation axial force F0, which is the axial force acting on the steering shaft 22, is calculated. The deviation axial force F0 is an axial force that reflects the actual vehicle condition in which a deviation occurs between the target state and the actual state of the steering wheel 6, including the effect of responsiveness. Therefore, the deviation axial force F0 is expressed as the reaction torque command value T * By incorporating this into the system, it becomes possible to generate appropriate steering feedback force that corresponds to the actual vehicle's movement. Furthermore, the driver will not experience any discomfort such as a feeling of sticking or resistance. 【0078】 (2-2) The processing circuit further performs a third process. The third process is to calculate an assist torque command value T1, which is a torque in the same direction as the steering direction of the steering wheel 5, based on the steering state of the steering wheel 5. Steering torque T hThis is a state variable that reflects the steering state of the steering wheel 5. The first process described above includes the process of converting the deviation axial force F0 into torque applied to the steering wheel 5 and calculating the axial force torque T2. The second process described above subtracts the axial force torque T2 from the assist torque command value T1 to obtain the reaction force torque command value T * This includes a process for calculating the appropriate reaction torque command value T, which reflects the actual vehicle conditions in which a deviation occurs between the target state and the actual state of the steering wheel 6, including the effects of responsiveness. * This is achieved. Therefore, it is possible to generate an appropriate steering reaction force that corresponds to the actual vehicle operation. 【0079】 (2-3) The steering system 2 has a shaft that rotates in conjunction with the steering wheel 6 and a steering motor 31 that generates a steering force to be applied to the steering shaft 22. The pinion shaft 21 is a shaft that rotates in conjunction with the steering wheel 6. Target pinion angle θ p * This is a state variable that reflects the target state of the steering wheel 6, and the steering angle θ of the steering wheel 5. s This is the target rotation angle of the pinion shaft 21, calculated based on the pinion angle θ. p This is a state variable that reflects the actual state of the steering wheel 6, and the rotation angle θ of the steering motor 31. b This is the rotation angle of the pinion shaft 21 calculated based on the following. Therefore, the target pinion angle θ p * and pinion angle θ p Based on the deviation, including the effect of responsiveness, it is possible to obtain an axial force that reflects the actual vehicle conditions in which a deviation occurs between the target state and the actual state of the steering wheel 6. 【0080】 (2-4) The first process described above involves the pinion angle deviation Δθ p The process includes calculating the deviation axial force F0 using a second deviation axial force map M2 that defines the relationship between the deviation axial force and the deviation axial force F0. The characteristics of the second deviation axial force map M2 are the pinion angle deviation Δθ. p As the value increases, the absolute value of the deviation axial force F0 is set to increase. With this configuration, the pinion angle deviation Δθ pAs increases, the absolute value of the axial deviation F0 increases. Therefore, the pinion angle deviation Δθ p As it increases, the reaction torque command value T * Consequently, the steering reaction force increases. The driver of the vehicle can appropriately recognize the actual vehicle state in which a deviation occurs between the target state and the actual state of the steering wheels 6, including the effect of responsiveness, through the feedback transmitted via the steering wheel 5. 【0081】 <Other Embodiments> This embodiment may be implemented with the following modifications. The axial force calculation unit 82 may calculate not only the deviation axial force F0, but also the angular axial force, current axial force, or mixed axial force. In this case, the axial force calculation unit 82 adds the deviation axial force F0 to the angular axial force, current axial force, or mixed axial force to calculate the final axial force, and converts the calculated final axial force into a torque for the steering shaft 11 to calculate the axial force torque T2. 【0082】 Angular axial force is, for example, the pinion angle θ. p This is an ideal axial force corresponding to the road surface conditions, and does not reflect the road surface conditions. The axial force calculation unit 82 calculates the angular axial force using, for example, an axial force map stored in memory. The axial force map is the pinion angle θ p The relationship between the angle axial force and the pinion angle θ is defined according to the vehicle speed V. The absolute value of the angle axial force is given by the pinion angle θ. p It increases as the absolute value of increases, and also as the vehicle speed V decreases. The axial force calculation unit 82 calculates the pinion angle θ p Instead, target pinion angle θ p * You may also use this method to calculate the angular axial force. 【0083】 Angular axial force reaction torque command value T * By being reflected in the pinion angle θ, pThis makes it possible to apply an appropriate steering reaction force to the steering wheel 5 accordingly. The driver can understand the steering state of the steering wheel 5 by feeling the steering reaction force through the steering wheel 5 as feedback. Since the angular axial force is an axial force that is not affected by the road surface condition, the road surface condition is not reflected in the steering reaction force. Therefore, the operability of the steering wheel 5 can be ensured. 【0084】 The current axial force is the current I of the steering motor 31. b The axial force is determined according to the value of and reflects the road surface condition. The axial force calculation unit 82 calculates, for example, the current I of the steering motor 31. b The current axial force is calculated by multiplying the value by the gain. The gain is a coefficient corresponding to the vehicle speed V. The current axial force is the reaction torque command value T. * By reflecting this, it becomes possible to apply steering feedback to the steering wheel 5 according to the road surface conditions. The driver can understand the road surface conditions by feeling the steering feedback through the steering wheel 5. 【0085】 Mixed axial force is an axial force obtained by mixing angular axial force and current axial force in a predetermined ratio. The ratio is a distribution ratio set individually for angular axial force and current axial force according to various state variables that reflect vehicle behavior, steering conditions, or road surface conditions. The mixed axial force is equal to the reaction torque command value T. * By reflecting this, it becomes possible to apply steering feedback to the steering wheel 5 according to the vehicle's behavior, steering state, or road surface conditions. The driver can understand the vehicle's behavior, steering state, or road surface conditions by feeling the steering feedback through the steering wheel 5. [Explanation of symbols] 【0086】 1... Steering control device 2… Steering gear 5… Steering wheel 6… Steering wheel 12… Reaction motor 22... Steering shaft 52…Reaction force torque command value calculation unit (processing circuit)

Claims

[Claim 1] A steering control device configured to control a steering system in which power transmission between the steering wheels and the steering wheel of a vehicle is separated, wherein the steering system includes a steering shaft configured to steer the steering wheels and a reaction motor configured to generate a steering reaction force to be applied to the steering wheel, The system includes a processing circuit configured to calculate a reaction torque command value for controlling the reaction motor based on the steering state of the steering wheel, and the processing circuit is configured to perform a first process and a second process. The first process is a process of calculating the axial force acting on the steering shaft based on the deviation between a first state variable that reflects the target state of the steering wheel and a second state variable that reflects the actual state of the steering wheel. The second process described above is a steering control device that calculates the reaction torque command value using the calculated axial force. [Claim 2] The processing circuit is configured to further perform a third process, The third process described above is a process that calculates an assist torque command value, which is a torque in the same direction as the steering direction of the steering wheel, based on the steering state of the steering wheel. The first process includes a process of converting the calculated axial force into a torque applied to the steering wheel to calculate the axial force torque, The steering control device according to claim 1, wherein the second process includes a process of calculating the reaction torque command value by subtracting the axial force torque from the assist torque command value. [Claim 3] The steering device has a shaft that rotates in conjunction with the steering wheel, The first state variable is a target steering angle ratio calculated based on the steering angle of the steering wheel, The steering control device according to claim 1 or claim 2, wherein the second state variable is an estimated steering angle ratio estimated from the steering angle and the rotation angle of the shaft. [Claim 4] The steering device comprises a shaft that rotates in conjunction with the steering wheel, and a steering motor configured to generate a steering force applied to the steering shaft. The first state variable is the target rotation angle of the shaft, which is calculated based on the steering angle of the steering wheel. The steering control device according to claim 1 or claim 2, wherein the second state variable is the rotation angle of the shaft calculated based on the rotation angle of the steering motor. [Claim 5] The first process includes a process of calculating the axial force using a map that defines the relationship between the deviation and the axial force, The steering control device according to claim 1 or claim 2, wherein the characteristics of the map are set such that the absolute value of the axial force increases as the deviation increases.

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