Vehicle alarm system

Abstract

To provide a warning apparatus for a vehicle, capable of reducing a sense of discomfort when causing the vibrations of a steering wheel as a warning.SOLUTION: A vehicle control device controls a motor for generating torque applied to a steering wheel and the driving of the motor. The control device controls the driving of the motor so as to cause the vibrations of the steering wheel as a warning when there occurs a situation where an own vehicle deviates from a traveling path. Further, when there occurs the situation where the vehicle deviates from the traveling path, the control device offsets the average value of the vibrations of the steering wheel as the warning through the control of the driving of the motor to suppress a change in the change characteristic of steering torque relative to a change in the steering angle of the steering wheel. For example, when calculating warning torque T2 as a wave motion which cyclically changes to vibrate the steering wheel, the control device corrects the value of the warning torque T2, thereby offsetting the average value of the vibrations of the steering wheel.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to an alarm device for a vehicle. [Background technology]

[0002] Conventionally, there are devices that warn the driver when the vehicle deviates from the roadway. For example, the warning device in Patent Document 1 has a motor that applies a driving force to a steering shaft and a control device that controls the motor. A steering wheel is attached to the steering shaft. The control device controls the power supply to the motor so that the steering wheel vibrates during the period when it is determined that the vehicle is deviating from the roadway.

[0003] The control device superimposes a micro-vibration component on the current supplied to the motor according to the steering angle of the steering wheel. The micro-vibration component is a current that changes in a sinusoidal manner, and the value of the current is stored in advance in the control device. When the micro-vibration component is superimposed on the motor current, the torque of the motor changes slightly, causing the steering wheel to vibrate slightly. This micro-vibration can make the driver aware that the vehicle is about to deviate from the road. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2000-251171 A Summary of the Invention [Problem to be solved by the invention]

[0005] The following concerns exist regarding conventional general warning devices that vibrate the steering wheel as a warning, including the warning device of Patent Document 1. That is, when the steering wheel is vibrated as a warning, it is considered that the friction characteristics of the steering device change when the torque of the motor for generating the vibration is applied to the steering wheel. This change in friction may cause the driver to feel an uncomfortable steering sensation.

[0006] An object of the present invention is to provide a vehicle alarm device that can reduce the sense of discomfort that occurs when the steering wheel is vibrated as an alarm. [Means for solving the problem]

[0007] A vehicle warning device that can achieve the above object includes a motor that generates a torque applied to a steering mechanism of a vehicle that is linked to the steering of a steering wheel, and a control device that controls the drive of the motor so that the steering wheel vibrates as a warning when a specific situation occurs in which a warning should be issued to a driver. This vehicle warning device is based on the premise that during a period in which the steering wheel is vibrated as a warning, the change characteristic of the steering torque relative to a change in the steering angle of the steering wheel changes from the change characteristic of the steering torque relative to a change in the steering angle of the steering wheel when the steering wheel is not vibrated as a warning. When the specific situation occurs, the control device adjusts the magnitude of the vibration by offsetting the average value of the vibration of the steering wheel as the warning through control of the drive of the motor in order to suppress the change in the change characteristic of the steering torque relative to the change in the steering angle of the steering wheel.

[0008] According to this configuration, when a specific situation occurs in which a warning should be issued to the driver, the average value of the vibration of the steering wheel is offset through control of the drive of the motor to adjust the magnitude of the vibration as a warning. This prevents the change in the steering torque change characteristic with respect to the change in the steering angle from changing compared to the change in the steering torque change with respect to the change in the steering angle when the steering wheel is not vibrated as a warning. This reduces the sense of discomfort felt when the steering wheel is vibrated as a warning.

[0009] In the above vehicle warning device, the control device may have a warning torque calculation unit that calculates a warning torque that should be generated by the motor as a wave to vibrate the steering wheel when the specific situation occurs. In this case, the warning torque calculation unit may correct a value of the warning torque to suppress a change in a change characteristic of the steering torque with respect to a change in the steering angle of the steering wheel when the specific situation occurs.

[0010] According to this configuration, when a specific situation occurs in which a warning should be issued to the driver, the warning torque value is corrected to suppress changes in the change characteristics of the steering torque relative to changes in the steering angle of the steering wheel. By adjusting the magnitude of the vibration of the steering wheel through this correction of the warning torque, the change in the change characteristics of the steering torque relative to changes in the steering angle is suppressed from changing compared to the change in the change characteristics of the steering torque relative to changes in the steering angle when the steering wheel is not vibrated as a warning. This reduces the sense of discomfort felt when the steering wheel is vibrated as a warning.

[0011] In the above-mentioned vehicle warning device, the steering mechanism may have a structure in which the steering wheel and steered wheels of the vehicle are connected to each other so as to be capable of transmitting power between them. In this case, the control device may have an assist torque calculation unit that calculates an assist torque in the same direction as the steering direction of the steering wheel based on the steering state of the steering wheel, and an adder that calculates a final torque to be generated by the motor by adding the warning torque calculated by the warning torque calculation unit and the assist torque calculated by the assist torque calculation unit.

[0012] According to this configuration, it is possible to generate vibration as a warning in the steering wheel by utilizing the motor that generates the assist torque. In the above-mentioned vehicle warning device, the steering mechanism may have a structure in which power transmission between the steering wheel and steered wheels is separated. In this case, the control device may have a steering reaction torque calculation unit that calculates a steering reaction torque, which is a torque in a direction opposite to the steering direction of the steering wheel, based on the steering state of the steering wheel, and an adder that calculates a final torque to be generated by the motor by adding the warning torque calculated by the warning torque calculation unit and the steering reaction torque calculated by the steering reaction torque calculation unit.

[0013] According to this configuration, it is possible to generate vibration as a warning in the steering wheel by utilizing the motor that generates the steering reaction torque. In the above vehicle warning device, the specific situation may include a situation in which the host vehicle deviates from a traveling path.

[0014] According to this configuration, the vibration of the steering wheel as a warning can make the driver aware that the vehicle is in danger of deviating from the traveling path. In the above-mentioned vehicle alarm device, the control device may start vibrating the steering wheel as an alarm when an alarm command generated by an on-board higher-level control device that determines the specific situation is received.

[0015] According to this configuration, it is possible to generate vibration of the steering wheel as a warning based on a warning command from a higher-level control device. Effect of the Invention

[0016] According to the vehicle alarm device of the present invention, it is possible to reduce the sense of discomfort felt when the steering wheel is vibrated as an alarm. [Brief description of the drawings]

[0017] [Figure 1] 1 is a configuration diagram of a first embodiment in which a vehicle alarm device is embodied in a steering device. [Diagram 2] FIG. 2 is a block diagram of a control device for a steering device according to the first embodiment. [Diagram 3] FIG. 11 is a block diagram of a comparative example of a warning torque calculation unit. [Figure 4] 11 is a graph showing a comparative example of a change in warning torque over time. [Diagram 5] 6 is a graph showing the relationship between steering torque and steering angle in a comparative example. [Figure 6] FIG. 2 is a block diagram of a warning torque calculation unit according to the first embodiment. [Figure 7] 5 is a flowchart showing a processing procedure of a warning torque calculation unit according to the first embodiment. [Figure 8] 5 is a graph showing a change over time in warning torque in the first embodiment. [Figure 9] 4 is a graph showing the relationship between steering torque and steering angle in the first embodiment. [Figure 10] FIG. 11 is a configuration diagram of a second embodiment in which a vehicle alarm device is embodied in a steer-by-wire type steering device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] <First embodiment> Hereinafter, a first embodiment of the vehicle warning device will be described, in which the vehicle steering device is an electric power steering device.

[0019] As shown in FIG. 1, the steering device 10 has a steering shaft 13, a pinion shaft 14, and a steered shaft 15 which function as a power transmission path between a steering wheel 11 and steered wheels 12, 12. The steering shaft 13, the pinion shaft 14, and the steered shaft 15 constitute a steering mechanism of the vehicle. The steered shaft 15 extends along the vehicle width direction (the left-right direction in FIG. 1). The steered wheels 12, 12 are connected to both ends of the steered shaft 15 via tie rods 16, 16. The pinion shaft 14 is provided so as to intersect with the steered shaft 15. The pinion teeth 14a of the pinion shaft 14 are engaged with the rack teeth 15a of the steered shaft 15. The steered shaft 15 moves linearly in conjunction with the rotation of the steering wheel 11. The linear movement of the steered shaft 15 is transmitted to the left and right steered wheels 12, 12 via the tie rods 16, thereby controlling the steering angle θ of the steered wheels 12, 12. w will be changed.

[0020] The steering device 10 also has a motor 21 and a speed reduction mechanism 22 as components for generating an assist torque, which is a force for assisting the steering by the driver. The motor 21 functions as an assist motor, which is a generating source of the assist torque. For example, a three-phase brushless motor is adopted as the motor 21. The motor 21 is connected to a pinion shaft 23 via the speed reduction mechanism 22. The pinion teeth 23a of the pinion shaft 23 are meshed with the rack teeth 15b of the steered shaft 15. The rotation of the motor 21 is decelerated by the speed reduction mechanism 22, and the decelerated rotational force is transmitted to the steered shaft 15 via the pinion shaft 23 as an assist torque. In response to the rotation of the motor 21, the steered shaft 15 moves along the vehicle width direction.

[0021] Incidentally, the steering device 10 does not have to be a type that applies an assist torque to the steered shaft 15. The steering device 10 may be a type that applies an assist torque to the steering shaft 13, for example. In this case, as shown by the two-dot chain line in Fig. 1, the motor 21 is connected to the steering shaft 13 via a reduction mechanism 22. The pinion shaft 23 may be omitted.

[0022] The steering device 10 also has a control device 50. The control device 50 controls the motor 21 based on the detection results of various sensors. The sensors include a torque sensor 51, a vehicle speed sensor 52, and a rotation angle sensor 53. The torque sensor 51 detects the steering torque T applied to the steering shaft 13 through the rotation of the steering wheel 11. h The vehicle speed sensor 52 detects the vehicle speed V. The rotation angle sensor 53 is provided on the motor 21. The rotation angle sensor 53 detects the rotation angle θ of the motor 21. m The control device 50 detects the steering torque T h The control device 50 executes an assist control to generate an assist torque according to the steering torque T h , a vehicle speed V detected by a vehicle speed sensor 52, and a rotation angle θ detected by a rotation angle sensor 53. m Based on this, the power supply to the motor 21 is controlled.

[0023] Here, a vehicle may be equipped with a driving assistance system that realizes various driving assistance functions to further improve the safety or convenience of the vehicle. An example of a driving assistance system is a lane departure warning system. In this case, a control device of the lane departure warning system is installed in the vehicle as a host control device 500 for the control device 50. The host control device 500 recognizes the lane through a camera installed on the windshield, for example, and generates an alarm command S for the control device 50 when it is determined that the vehicle is likely to cross the lane. The alarm command S is an electric signal for prompting the control device 50 to output an alarm when a specific situation that should be issued to the driver has occurred. The host control device 500 switches its own driving assistance function between on and off through the operation of a switch (not shown) installed in the driver's seat or the like. In other words, the host control device 500 operates only during the period when the driving assistance function is on. Incidentally, the host control device 500 may also be installed in the camera mentioned above.

[0024] Next, the control device 50 will be described in detail. 2, the control device 50 includes a microcomputer 50A and a drive circuit 50B. The microcomputer 50A detects a steering torque T h , and the current command value I * The drive circuit 50B calculates the current command value I * A drive power according to the above is supplied to the motor 21.

[0025] The microcomputer 50A has an assist torque calculation unit 61, a warning torque calculation unit 62, an adder 63, and a current command value calculation unit 64. These calculation units are functional parts that are realized by the CPU (Central Processing Unit) of the microcomputer 50A executing a control program. However, the fact that each calculation unit is realized by software is merely an example, and at least some of the calculation units may be realized by hardware such as a logic circuit.

[0026] The assist torque calculation unit 61 calculates the steering torque T h The assist torque calculation unit 61 calculates an assist torque T1 that is a torque to be generated by the motor 21 based on the steering torque T h As the absolute value of T increases and the vehicle speed V decreases, a larger absolute value of the assist torque T1 is calculated.

[0027] The warning torque calculation unit 62 takes in the warning command S generated by the upper control device 500. When the warning command S is taken in, the warning torque calculation unit 62 calculates a warning torque T2 as a process for issuing a warning to alert the driver. The warning torque T2 is a minute vibration component that is set based on the viewpoint of generating minute vibrations in the torque generated by the motor 21. The warning torque T2 is set as a sine wave that is a wave that changes periodically with respect to time. The warning torque calculation unit 62 continues to output the warning torque T2 in a determined output pattern during the period in which the warning command S is output from the upper control device 500. When the warning command S from the upper control device 500 is discontinued, the warning torque calculation unit 62 stops outputting the warning torque T2. At this time, the value of the warning torque T2 is "0".

[0028] Incidentally, the output pattern of the warning torque T2 is initially set in advance at the design stage, and is an alternating combination of continuation and pause of the output of the warning torque T2. The amplitude of the warning torque T2, the vibration frequency of the warning torque T2, the duration for which the output of the warning torque T2 is continued, and the pause time for which the output of the warning torque T2 is paused are stored in a storage device (not shown) of the control device 50.

[0029] The adder 63 calculates the target assist torque T3 by adding the assist torque T1 calculated by the assist torque calculation unit 61 and the warning torque T2 calculated by the warning torque calculation unit 62. When the warning command S is not generated by the upper control device 500, the assist torque T1 calculated by the assist torque calculation unit 61 is used as it is as the target assist torque T3.

[0030] The current command value calculation unit 64 calculates a current command value I * The current command value I * is a target value of the current required for the motor 21 to generate the target assist torque T3.

[0031] When the warning torque T2, which is a minute vibration component, is calculated by the warning torque calculation unit 62, the current command value I * vibrates according to the output pattern of the warning torque T2. Therefore, the drive current supplied from the drive circuit 50B to the motor 21, and therefore the torque generated by the motor 21, also vibrates according to the output pattern of the warning torque T2. This causes the steering wheel 11 to vibrate slightly. The driver feels the slight vibration of the steering wheel 11 as a steering feel, and is able to recognize that the vehicle is about to deviate from the road.

[0032] Here, a comparative example will be described for the warning torque calculation unit 62. As the warning torque calculation unit 62, it is considered that the following configuration is adopted. As shown in FIG. 3, the warning torque calculation section 62 has a vibration calculation section 62A and a multiplier 62B.

[0033] The vibration calculation unit 62A calculates the reference sine wave S when the alarm command S calculated by the upper control device 500 is received. sin Calculate the reference sine wave S sin is a sine wave with an amplitude of "1". The reference sine wave S sinThe vibration frequency of the reference sine wave S is preset at the design stage. The vibration calculation unit 62A calculates the reference sine wave S according to the output pattern of the warning torque T2 that is initially set at the design stage. sin The output is alternately continued and paused.

[0034] The multiplier 62B multiplies the reference sine wave S calculated by the vibration calculation unit 62A. sin , and an amplitude value A0, which is a fixed value stored in the storage device of the control device 50. This amplitude value A0 is set in advance in the design stage as the amplitude of the warning torque T2. sin The warning torque T2 is calculated by multiplying the amplitude value A0 by the reference sine wave S. The amplitude of the warning torque T2 is the same as the amplitude value A0. The vibration frequency of the warning torque T2 is the same as the reference sine wave S. sin is the same as the vibration frequency of

[0035] An example of the output pattern of the warning torque T2 is as follows. As shown in the graph of Fig. 4, the output of the warning torque T2 is initiated in response to the output of the warning command S from the upper control device 500 (time t0). The warning torque T2 is output continuously for a duration ΔTA (time t1), and then the output is paused for a pause time ΔTB. After the pause time ΔTB has elapsed (time t2), the warning torque T2 is again output continuously for the duration ΔTA. Thereafter, during the period in which the warning command S is output from the upper control device 500, the output and pause of the warning torque T2 are alternately repeated.

[0036] However, when vibration is generated as a warning in the steering wheel 11 using the warning torque T2 calculated by the warning torque calculation unit 62 of the comparative example, the following concerns arise.

[0037] As shown in the graph of FIG. 5, the steering torque T h The absolute value of the steering angle θ s In the case where the steering wheel 11 is not vibrated as a warning, the steering angle θ sThe steering torque T h The absolute value of changes as shown by the dashed line in the graph of FIG. 5. In addition, when vibration is generated as a warning in the steering wheel 11, the steering angle θ s The steering torque T h The absolute value of varies in an oscillating manner as shown by the solid line in the graph of FIG.

[0038] Here, the steering torque T during the period when the vibration as a warning is generated in the steering wheel 11 is h Consider the average torque, which is the average of As shown by the dashed line in the graph of FIG. 5, when the steering wheel 11 is steered to the right, for example, the average torque when the vibration occurs is equal to the steering torque T h (see the dashed line in FIG. 5). In other words, when the steering wheel 11 is being steered to the right, the steering torque T h This raises concerns that the driver may feel a lack of response or a sense of steering slippage.

[0039] In addition, when the steering wheel 11 is turned back from the right direction to the left direction, the average torque at the time of vibration generation is the steering torque T h (see the dashed line in FIG. 5). That is, when the steering wheel 11 is turned back to the left and vibration is generated in the steering wheel 11 as a warning, the steering torque T h This also raises the concern that the driver may feel some discomfort in the steering sensation.

[0040] Therefore, in this embodiment, the warning torque calculation unit 62 has the following configuration. As shown in FIG. 6, the warning torque calculation section 62 has a correction torque calculation section 62C and an adder 62D in addition to the vibration calculation section 62A and multiplier 62B described above.

[0041] The multiplier 62B multiplies the reference sine wave S calculated by the vibration calculation unit 62A. sin and the amplitude value A0 stored in a storage device (not shown) of the control device 50. The multiplier 62B multiplies the reference sine wave S sin By multiplying the amplitude value A0 by the pre-alarm torque T2 pre Calculate the following.

[0042] The correction torque calculation unit 62C calculates the reference sine wave S sin The correction torque calculation unit 62C takes in the reference sine wave S sin The correction torque Tc is calculated during the period when the warning signal is output. The correction torque Tc is calculated based on the steering torque T h The correction torque Tc is set in advance, for example, through a simulation using a device model, and is stored in a storage device (not shown) of the control device 50. The correction torque calculation unit 62C calculates the steering torque T h In response to the change in the steering torque T h A correction torque Tc in the direction in which the absolute value of increases is calculated.

[0043] Incidentally, the correction torque calculation unit 62C is sin Alternatively, the correction torque Tc may be calculated during the period in which the final warning torque T2 calculated by an adder 62D, which will be described later, is being output.

[0044] The adder 62D multiplies the pre-warning torque T2 calculated by the multiplier 62B by pre and the correction torque Tc calculated by the correction torque calculation unit 62C is taken in, and the pre-warning torque T2 preThe final warning torque T2 is calculated by adding the correction torque Tc to the warning torque Tk.

[0045] Next, the procedure of the calculation process in the warning torque calculation unit 62 will be described. As shown in the flowchart of Fig. 7, the warning torque calculation unit 62 judges whether or not vibration is being generated as a warning of the steering wheel 11 (step S101). The warning torque calculation unit 62 receives the reference sine wave S sin When the reference sine wave S is output, it is determined that a vibration is being generated as a warning. sin When the signal is not being output, it is determined that vibration as an alarm is not occurring.

[0046] When it is determined that vibration as a warning is occurring (YES in step S101), the warning torque calculation unit 62 calculates the correction torque Tc (step S102), and the process proceeds to step S104.

[0047] When it is determined that vibration serving as a warning is not occurring (NO in step S101), the warning torque calculation unit 62 does not calculate the correction torque Tc, i.e., sets the value of the correction torque Tc to "0" (step S103), and proceeds to step S104.

[0048] In step S104, the warning torque calculation unit 62 calculates a final warning torque T2 based on the following equation (1) using the value of the correction torque Tc determined in the previous step S102 or step S103.

[0049] T2=T2 pre +Tc …(1) With this, the calculation process of the warning torque calculation unit 62 is completed. Next, the operation of the first embodiment will be described.

[0050] As shown by the dashed line in the graph of Fig. 8, when the vibration of the steering wheel 11 as a warning is started, the correction torque Tc is calculated. For example, when the steering wheel 11 is turned to the right, when the vibration of the steering wheel 11 as a warning is generated, the steering torque T h In addition, when the steering wheel 11 is turned back to the left, for example, and vibration is generated in the steering wheel 11 as a warning, the steering torque T h As shown by the solid line in the graph of FIG. 8, the final warning torque T2 reflecting the correction torque Tc is calculated as a negative correction torque Tc in a direction that reduces the absolute value of the pre-warning torque T2 before the correction torque Tc is reflected. pre In other words, the average value of the final warning torque T2 reflecting the correction torque Tc is equal to the average value of the pre-warning torque T2 before the correction torque Tc is reflected. pre The average value of the correction torque Tc is offset in the same direction as the correction torque Tc according to the absolute value of the correction torque Tc.

[0051] In this way, the correction torque Tc is reflected in the warning torque T2 for vibrating the steering wheel 11 as a warning. h and steering angle θ s The relationship with is as follows:

[0052] As shown by the dashed line in the graph of FIG. 9, when the steering wheel 11 is steered to the right, for example, the average torque when vibration occurs is equal to the steering torque T h (see the dashed line in FIG. 9). That is, when the steering wheel 11 is steered to the right and the steering torque T hThis suppresses the driver from experiencing discomfort such as a lack of steering response or a feeling of steering slippage.

[0053] In addition, even when the steering wheel 11 is steered back from the right direction to the left direction, the average torque at the time of vibration generation is the steering torque T h (see the dashed line in FIG. 5). That is, when the steering wheel 11 is steered back to the left and the steering wheel 11 generates a vibration as a warning, the steering torque T h Therefore, the driver is prevented from feeling any discomfort when steering.

[0054] Therefore, according to the first embodiment, the following effects can be obtained. (1) When the vehicle deviates from the road, the average value of the vibration amplitude of the steering wheel 11 is offset through the control of the drive of the motor 21, thereby adjusting the magnitude of the vibration as a warning. s Change in steering torque T h The change characteristic of the steering angle θ s Change in steering torque T h In addition, the fluctuation of the friction characteristic is also suppressed. Therefore, it is possible to reduce the sense of discomfort felt when the steering wheel 11 is vibrated as a warning.

[0055] (2) When the vehicle deviates from the road, the steering angle θ s Change in steering torque T h The value of the warning torque T2 is corrected so as to suppress the change in the characteristic of the change in the steering angle θ s Change in steering torque T hThe change characteristic of the steering angle θ s Change in steering torque T h Therefore, it is possible to reduce the sense of incongruity felt when the steering wheel 11 is vibrated as a warning.

[0056] (3) The motor 21 that generates the assist torque can be used to generate vibrations in the steering wheel 11 as a warning. <Second embodiment> Next, a second embodiment in which the vehicle alarm device is embodied in a steer-by-wire steering device will be described. Note that the same members and configurations as those in the first embodiment are given the same reference numerals and detailed descriptions thereof will be omitted.

[0057] As shown in Fig. 10, a steer-by-wire steering device 100 has a reaction unit 100A that applies a steering reaction torque to the steering wheel 11. The steering reaction torque is a torque that acts in the opposite direction to the operation direction of the steering wheel 11 by the driver. By applying the steering reaction torque to the steering wheel 11, it is possible to give the driver an appropriate sense of responsiveness.

[0058] The reaction force unit 100A has a steering shaft 13 to which the steering wheel 11 is connected, and a torque sensor 51 provided on the steering shaft 13. However, the steering shaft 13 constitutes a steering mechanism of the vehicle, and power transmission between the steering shaft 13 and the steered wheels 12 is separated.

[0059] The reaction force unit 100 A further includes a reaction force motor 101 , a speed reducing mechanism 102 , a rotation angle sensor 103 and a control device 104 . The reaction motor 101 is a generating source of steering reaction torque. The reaction motor 101 is connected to the steering shaft 13 via a reduction gear mechanism 102. The reduction gear mechanism 102 is provided on a portion of the steering shaft 13 opposite the steering wheel 11 with respect to the torque sensor 51. The torque generated by the reaction motor 101 on the steering shaft 13 is applied to the steering shaft 13 as steering reaction torque.

[0060] The rotation angle sensor 103 is provided on the reaction motor 101. The rotation angle sensor 103 detects the rotation angle θ of the reaction motor 101. a Detect. The control device 104 controls the driving of the reaction motor 101 to generate a steering torque T h The control device 104 executes a reaction force control to generate a steering reaction force torque according to the steering torque T detected through the torque sensor 51. h The control device 104 calculates a target steering reaction torque based on the rotation angle θ of the reaction motor 101 detected through the rotation angle sensor 103 and controls the power supply to the reaction motor 101 so that the reaction motor 101 generates the calculated target steering reaction torque. a Based on this, the steering angle θ s Calculate the following.

[0061] The control device 104 has a configuration similar to that of the first embodiment shown in Fig. 2. That is, as shown by the reference characters in parentheses in Fig. 2, the control device 104 has a microcomputer 104A and a drive circuit 104B. The microcomputer 104A has a steering reaction force torque calculation unit 161, a warning torque calculation unit 162, an adder 163, and a current command value calculation unit 164.

[0062] The steering reaction torque calculation unit 161 calculates the steering torque T h , and the vehicle speed V detected by the vehicle speed sensor 52. The steering reaction torque calculation unit 161 calculates a steering reaction torque T11 that is a torque to be generated by the motor 21 based on the steering torque T hAs the absolute value of increases and the vehicle speed V decreases, a steering reaction torque T11 with a larger absolute value is calculated.

[0063] The warning torque calculation unit 162 receives the warning command S generated by the upper control device 500. When the warning command S is received, the warning torque calculation unit 162 calculates a warning torque T12 as a process for issuing a warning to alert the driver. The output pattern of the warning torque T12 is the same as that of the first embodiment. That is, during the period when the warning command S is being output from the upper control device 500, the output of the warning torque T2 is alternately continued and paused.

[0064] The adder 163 calculates a target steering reaction torque T13 by adding the steering reaction torque T11 calculated by the steering reaction torque calculation unit 161 and the warning torque T12 calculated by the warning torque calculation unit 162. When the warning command S is not generated by the upper level control device 500, the steering reaction torque T11 calculated by the steering reaction torque calculation unit 161 is used as it is as the target steering reaction torque T13.

[0065] The current command value calculation unit 164 calculates a current command value I for the reaction motor 101 based on the target steering reaction torque T13 calculated by the adder 163. * Calculate the following. The warning torque calculation unit 162 has a configuration similar to that of the first embodiment shown in Fig. 6. That is, the warning torque calculation unit 162 has a vibration calculation unit 62A, a multiplier 62B, a correction torque calculation unit 62C, and an adder 62D. The warning torque calculation unit 162 calculates the warning torque T12 through a processing procedure similar to that of the first embodiment shown in the flowchart of Fig. 7. Therefore, when the steering wheel 11 is vibrated as a warning, the correction torque Tc is reflected in the warning torque T2, which is the torque for vibrating the steering wheel 11 as a warning. Therefore, the steering torque T h and steering angle θ s As a result, the relationship shown in the graph of FIG. 9 can be obtained.

[0066] Therefore, according to the second embodiment, in a steer-by-wire steering device, in addition to the effects (1) and (2) of the first embodiment, the following effect can be obtained.

[0067] (4) The reaction motor 101 that generates a steering reaction torque can be used to generate vibration in the steering wheel 11 as a warning. <Other embodiments> The first and second embodiments may be modified as follows.

[0068] In the first and second embodiments, in addition to the warning to prevent the vehicle from leaving the lane as a driving assistance function, vibrations may be generated in the steering wheel 11 as a warning to prevent drowsiness at the wheel or to avoid a collision.

[0069] In the first and second embodiments, when any driving assistance function is stopped, the steering wheel 11 may vibrate as an alarm to warn of the stop of the function. For example, when a lane keeping assist system is installed in the vehicle, the lane keeping assist system function is stopped when the vehicle deviates from the road. At this time, the driver may be warned that the lane keeping assist system function is stopped by vibrating the steering wheel 11. Incidentally, the lane keeping assist system is a system that assists the operation of the steering wheel 11 so that the vehicle keeps running near the center of the lane, for example, for the purpose of reducing the driving burden on the driver when driving on a highway.

[0070] In the first and second embodiments, the warning torque T2 is set as a sine wave in which positive and negative values ​​change periodically, but this is not limiting. For example, the warning torque T2 may be set as a non-periodic wave such as a decay curve expressed by the product of an exponential function and a trigonometric function, or as a non-sine wave such as a triangular wave or a rectangular wave.

[0071] In the first embodiment, the warning torque T2, which is a minute vibration component, is added to the assist torque T1 in order to generate a vibration as a warning in the steering wheel 11, but the following may be done. That is, the warning current, which is a minute vibration component, is added to a current command value calculated based on the assist torque T1. In this way, it is possible to generate a vibration as a warning in the steering wheel 11.

[0072] In the second embodiment, the warning torque T12, which is a minute vibration component, is added to the steering reaction torque T11 in order to generate a vibration as a warning in the steering wheel 11, but it may be done as follows. That is, the warning current, which is a minute vibration component, is added to a current command value calculated based on the steering reaction torque T11. In this way, it is possible to generate a vibration as a warning in the steering wheel 11.

[0073] In the first embodiment, the motor 21 that generates the assist torque is used to generate vibrations as an alarm in the steering wheel 11, but a dedicated actuator for generating vibrations as an alarm in the steering wheel 11 may be provided separately from the motor 21. This actuator includes a motor.

[0074] In the second embodiment, the reaction motor 101 that generates the steering reaction torque is used to generate vibration as an alarm in the steering wheel 11, but a dedicated actuator for generating vibration as an alarm in the steering wheel 11 may be provided separately from the reaction motor 101. This actuator includes a motor. [Explanation of symbols]

[0075] 10...Steering device (vehicle warning device) 11…Steering wheel 21…Motor 50...Control device 61... Assist torque calculation unit 62...Warning torque calculation unit 63...Adder 100...Steering device (vehicle alarm device) 101...Reaction motor 104...Control device 161...Steering reaction torque calculation unit 162...Alarm torque calculation unit 163…Adder 500...High-level control device

Claims

1. a motor that generates a torque that is applied to a steering mechanism of a vehicle in conjunction with the steering of a steering wheel; a control device that controls the driving of the motor so that the steering wheel vibrates as a warning when a specific situation occurs in which a warning should be issued to a driver, on the premise that, during a period in which the steering wheel is vibrated as the warning, a change in friction characteristic of the steering mechanism caused by the vibration of the steering wheel causes a change in a change in a steering torque characteristic relative to a change in a steering angle of the steering wheel compared to a change in a steering torque characteristic relative to a change in a steering angle of the steering wheel in a case in which the steering wheel is not vibrated as the warning, the control device is configured to adjust a magnitude of the vibration of the steering wheel by offsetting an average value of the vibration of the steering wheel as the warning through control of driving of the motor, in order to suppress a change in a characteristic of a change in a steering torque with respect to a change in a steering angle of the steering wheel, when the specific situation occurs; the control device has a warning torque calculation unit that calculates a warning torque that is to be generated as a wave by the motor so as to vibrate the steering wheel when the specific situation occurs, The warning torque calculation unit calculates a pre-warning torque by multiplying a reference sine wave, which is a sine wave having an amplitude of "1", by a predetermined amplitude value, and When the steering wheel is turned inward or outward, a correction torque in the same direction as the steering direction of the steering wheel is added to the pre-warning torque, and an average value of the pre-warning torque is offset in the same direction as the steering direction of the steering wheel by an absolute value of the correction torque, thereby calculating a final warning torque. The warning torque calculation unit is configured to gradually reduce the absolute value of the correction torque toward zero during a period in which the steering wheel continues to vibrate, thereby changing the amplitude of the warning torque so that the amplitude of the warning torque in the same direction as the steering direction of the steering wheel approaches the amplitude of the warning torque in the opposite direction to the steering direction of the steering wheel.

2. The steering mechanism has a structure in which the steering wheel and steered wheels of a vehicle are connected to each other so as to be capable of transmitting power therebetween, The control device includes an assist torque calculation unit that calculates an assist torque, which is a torque in the same direction as a steering direction of the steering wheel, based on a steering state of the steering wheel; 2. The vehicle warning device according to claim 1, further comprising: an adder that calculates a final torque to be generated by the motor by adding the warning torque calculated by the warning torque calculation unit and the assist torque calculated by the assist torque calculation unit.

3. The steering mechanism has a structure in which power transmission between the steering wheel and the steered wheels is separated, The control device includes a steering reaction torque calculation unit that calculates a steering reaction torque, which is a torque in a direction opposite to a steering direction of the steering wheel, based on a steering state of the steering wheel; 2. The vehicle warning device according to claim 1, further comprising: an adder that calculates a final torque to be generated by the motor by adding up the warning torque calculated by the warning torque calculation unit and the steering reaction torque calculated by the steering reaction torque calculation unit.

4. 4. The vehicle alarm device according to claim 1, wherein the specific situation includes a situation in which the host vehicle deviates from a traveling road.

5. The vehicle alarm device according to any one of claims 1 to 4, wherein the control device starts vibrating the steering wheel as the alarm when an alarm command generated by an on-board higher-level control device that determines the specific situation is received.

Images