JP2010184638A - Steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering device that enhances reliability on the determination whether a steering part is in a hands free state or not. <P>SOLUTION: The steering device 1 is equipped on a steering wheel 2 of a vehicle and includes: a first vibration sensor 4 detecting the vibration of the steering wheel 2; a second vibration sensor equipped on a steering column 3 connected to the back surface of the steering wheel 2 to detect the vibration of a steering column 3; and an ECU 6 that calculates a resonant frequency W and a vibration transmission level L of the steering wheel 2 from the detected result of the first vibration sensor 4 and the second vibration sensor 5, stores the resonant frequency W and the vibration transmission level L in a hands free state where the vehicle driver is not holding the steering wheel 2 as hands free state threshold values, and determines whether the steering wheel 2 is in a hands free state or not based on the calculated result and the stored hands free state threshold values. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a steering device.

  2. Description of the Related Art Conventionally, a steering device described in Patent Document 1 is known as a steering device that determines whether or not a driver is in a released state where the steering unit is not held. The steering apparatus described in Patent Document 1 includes an excitation unit that applies vibration to the steering unit, and a vibration detection unit that detects a vibration state of the steering unit, and when the predetermined vibration is applied by the excitation unit. It is determined from the change in the vibration state of the steering unit whether the hand is in the released state.

JP 2007-204005 A

  By the way, in the above-described conventional steering device, when the vehicle travels on a rough road surface or the like, the vibration is transmitted to the steering unit and the vibration state changes, which may hinder accurate determination of the steered state. there were.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a steering device capable of improving the reliability with respect to the determination as to whether or not the steering unit is in a let-off state. To do.

  A steering device according to the present invention is provided in a steering portion of a vehicle, and includes a first vibration sensor that detects vibration of the steering portion, and a steering column that is connected to the steering portion and detects vibration of the steering column. 2 vibration sensors, calculation means for calculating the resonance frequency and vibration transmission level of the steering unit from the detection results of the first vibration sensor and the second vibration sensor, and the driver of the vehicle does not hold the steering unit Whether the steering unit is in the release state based on the storage means for storing the resonance frequency and vibration transmission level in the release state as the release reference state, and the calculation result of the calculation means and the release reference state stored in the storage means Determining means for determining whether or not.

  In the steering apparatus according to the present invention, vibrations of the steering unit and the steering column due to vehicle travel, engine drive, and the like are detected, and the resonance frequency and vibration transmission level of the steering unit are calculated based on the detection results. . Since the resonance frequency and vibration transmission level of the steering unit change depending on whether the driver holds the steering unit or not, the calculated resonance frequency and vibration transmission level and the resonance frequency in the hand-off state and By comparing the vibration transmission level (ease of transmission of vibration from the steering column to the steering unit), it is possible to determine whether or not the steering unit is in the hand-off state. Therefore, according to this steering device, it is possible to determine whether or not the vehicle is in the released state without depending on the vibration state applied to the steering unit. Therefore, it is preferable even when the vehicle is traveling on a rough road surface. A determination is made, thereby improving the reliability of the determination.

  In addition, the storage means stores a plurality of steering reference states in which the steering holding force of the driver with respect to the steering unit is changed in stages, and the determination unit determines that the steering unit is not in the hand-off state. The holding state of the steering unit is preferably determined based on a plurality of steering holding reference states. According to such a configuration, by comparing the resonance frequency and vibration transmission level calculated by the calculation means with a plurality of stored steering reference states, the driver's steering state (light steering state) with respect to the steering unit It is possible to determine a strong steering state, etc.).

  In addition, it further comprises estimation means for estimating the driver's steering holding force with respect to the steering unit based on the difference between the resonance frequency and vibration transmission level calculated by the calculation means and the hand-off reference state, and the determination means is estimated by the estimation means. It is preferable to determine that the driver is in a driving operation tension state when the steering holding force is equal to or greater than a predetermined threshold. In a driving operation tension state where the driver is driving with tension, such as when driving on a steep winding road, the driver holds the steering part strongly, and the steering force is often high. Therefore, when the driver's steering force is greater than or equal to a predetermined value, the driver determines that the driver is in a driving operation tension state, and makes various in-vehicle systems such as EPS [Electric Power Steering] function according to the determination result. Thus, it is possible to obtain vehicle motion characteristics according to the situation.

  Moreover, it is preferable that a determination means determines that it is an emergency state, when the variation | change_quantity per unit time of the resonant frequency and vibration transmission level which the calculation means calculated is more than a predetermined threshold value. In an emergency state, such as when a pedestrian suddenly appears in front of the vehicle, the driver often suddenly and firmly grips the steering unit. In this case, the resonance frequency and vibration transmission level of the steering unit change greatly in a short time. Therefore, when the amount of change in the resonance frequency and vibration transmission level per unit time is greater than or equal to a predetermined value, it is determined that there is an emergency state, and various in-vehicle systems such as EPS [Electric Power Steering] are installed according to the determination result. By making it function, the vehicle motion characteristic according to the situation can be obtained.

  According to the present invention, it is possible to improve the reliability related to the determination as to whether or not the steering unit is in the hand-off state.

1 is a configuration diagram illustrating a first embodiment of a steering apparatus according to the present invention. It is a flowchart which shows operation | movement of ECU of FIG. It is a flowchart which shows operation | movement of ECU of the steering apparatus which concerns on 2nd Embodiment.

  Hereinafter, a first embodiment of a steering apparatus according to the present invention will be described in detail with reference to the drawings.

[First Embodiment]
As shown in FIG. 1, a steering apparatus 1 according to this embodiment includes a steering wheel (steering unit) 2 for a driver to drive a vehicle, and a steering column 3 connected to the back surface of the steering wheel 2. ing. The steering column 3 is fixed to the vehicle body side by a bracket (not shown). The steering wheel 2 and the steering column 3 are transmitted with vibrations generated by driving the engine and traveling of the vehicle through a bracket or the like.

  The steering wheel 2 is provided with a first vibration sensor 4 that detects vibration of the steering wheel 2, and the steering column 3 is provided with a second vibration sensor 5 that detects vibration of the steering column 3. Yes. The first vibration sensor 4 and the second vibration sensor 5 are electrically connected to an ECU [Electric Control Unit] (calculation means, determination means) 6 which is an electronic control unit.

  The first vibration sensor 4 is embedded in, for example, the approximate center of the steering wheel 2. The first vibration sensor 4 detects a vibration T1 in the circumferential direction of the steering wheel 2 (a direction substantially orthogonal to the extending direction of the steering column 3), and transmits the detection result to the ECU 6.

  The second vibration sensor 5 is fixed on the outer surface of the steering column 3, for example. The second vibration sensor 5 detects a vibration T2 in a direction substantially orthogonal to the extending direction of the steering column 3, and transmits the detection result to the ECU 6.

  The ECU 6 includes a CPU [Central Processing Unit] that performs arithmetic processing, a ROM [Read Only Memory] and a RAM [Random Access Memory] that are storage units, an input signal circuit, an output signal circuit, a power supply circuit, and the like. The apparatus 1 is comprehensively controlled. The ECU 6 is electrically connected to various in-vehicle systems such as an engine control unit, VGRS [Variable Gear Ratio Steering], and EPS [Electric Power Steering].

  The ECU 6 determines the resonance frequency W and the vibration transmission level L based on the vibration T1 of the steering wheel 2 transmitted from the first vibration sensor 4 and the vibration T2 of the steering column 3 transmitted from the second vibration sensor 5. Calculate. Specifically, the ECU 6 calculates a transfer function G when the vibration T2 of the steering column 3 is input and the vibration T1 of the steering wheel 2 is output. Then, the resonance frequency W and the vibration transmission level L of the steering wheel 2 are calculated from the transfer function G. Here, the vibration transmission level L is the ease of transmission of vibration from the steering column 3 to the steering wheel 2.

  The ECU 6 stores in advance the resonance frequency W0 and the vibration transmission level L0 when the driver does not hold the steering wheel 2 as a release state threshold value. In addition, the ECU 6 stores in advance the resonance frequency W1 and the vibration transmission level L1 when the driver holds the steering wheel 2 lightly, such as when holding the steering wheel with one hand, as the first holding state threshold value. Similarly, the ECU 6 stores in advance the resonance frequency W2 and the vibration transmission level L2 when the driver grips the steering wheel 2 with a normal strength as the second steered state threshold value. In addition, as a method of obtaining these steered state threshold values, a resonance frequency and a vibration transmission level in a fixed state in which the driver firmly holds and fixes the steering wheel 2 are set as the fixed state threshold values, and the fixed state threshold value and the hand-off state are set. There is a method of obtaining the first and second steered state threshold values by setting levels between the threshold values in stages.

  The ECU 6 determines whether or not the resonance frequency W and the vibration transmission level L obtained by the calculation are equal to or greater than the hand-off state threshold (that is, W0 ≦ W and L0 ≦ L). When the ECU 6 determines that the resonance frequency W and the vibration transmission level L are less than the release state threshold value, the ECU 6 determines that the driver is in the release state in which the steering wheel 2 is not held. When it is determined that the ECU 6 is in the released state, the ECU 6 transmits the determination result to various in-vehicle systems of the vehicle. These various in-vehicle systems, for example, when an accelerator pedal operation is detected in a state in which a determination result of the release state is transmitted from the ECU 6, an alarm is sounded in the vehicle and a brake is automatically activated. .

  On the other hand, when the ECU 6 determines that the resonance frequency W and the vibration transmission level L are equal to or higher than the hand-off state threshold, the ECU 6 determines that the driver is holding the steering wheel 2. When the ECU 6 determines that the driver is holding the steering wheel 2, the resonance frequency W and the vibration transmission level L are equal to or higher than the first steering state threshold (that is, W1 ≦ W and L1 ≦ L). Determine whether.

  When the ECU 6 determines that the resonance frequency W and the vibration transmission level L are equal to or higher than the first steered state threshold value, the ECU 6 determines that the driver is in the light steered state in which the driver is lightly holding the steering wheel 2. When it is determined that the ECU 6 is in a light steering state, the ECU 6 transmits the determination result to various in-vehicle systems. These various in-vehicle systems, for example, when a determination result of a light steering state is transmitted from the ECU 6, increase the assist force by the EPS to reduce the steering force, and lane keep assist that supports driving along the lane Take measures such as increasing the assistance by the mechanism.

  On the other hand, when the ECU 6 determines that the resonance frequency W and the vibration transmission level L are equal to or higher than the first steering state threshold value, the resonance frequency W and the vibration transmission level L are equal to or higher than the second steering state threshold value (that is, W2 ≦ It is determined whether or not W and L2 ≦ L).

  When the ECU 6 determines that the resonance frequency W and the vibration transmission level L are equal to or higher than the second steering state threshold, the ECU 6 determines that the driver is in a strong steering state in which the steering wheel 2 is strongly held. When it is determined that the ECU 6 is in a strong steering state, the determination result is transmitted to various in-vehicle systems. For example, when a determination result indicating a strong steering state is transmitted from the ECU 6, these various in-vehicle systems take measures such as reducing the assist force by the EPS and giving a steering response.

  On the other hand, when the ECU 6 determines that the resonance frequency W and the vibration transmission level L are less than the second steered state threshold value, the ECU 6 determines that it is a normal steered state that is neither a strong steered state nor a light steered state. . When it is determined that the ECU 6 is in a normal steering state, the ECU 6 transmits the determination result to various in-vehicle systems. These various in-vehicle systems take measures such as returning the assist force by the EPS and the assist by the lane keep assist mechanism to a standard state when the determination result of the normal steering state is transmitted from the ECU 6, for example.

  Next, the operation of the ECU 6 in the steering device 1 will be specifically described with reference to the drawings.

  As shown in FIG. 2, first, the detection result of the vibration T1 of the steering wheel 2 is transmitted from the first vibration sensor 4, and the detection result of the vibration T2 of the steering column 3 is transmitted from the second vibration sensor 5. (S1). Based on these detection results, the resonance frequency W and the vibration transmission level L of the steering wheel 2 are calculated (S2).

  Subsequently, it is determined whether or not the resonance frequency W and the vibration transmission level L obtained by the calculation are equal to or greater than the let-off state threshold (S3). When it is determined that the resonance frequency W and the vibration transmission level L are not equal to or higher than the hand-off state threshold, it is determined that the driver is in the hand-off state where the steering wheel 2 is not held (S4). When it is determined that the hand is released, the process proceeds to step S10.

  On the other hand, when it is determined that the resonance frequency W and the vibration transmission level L are equal to or greater than the hand-off state threshold, it is determined that the driver is holding the steering wheel 2. When it is determined that the driver holds the steering wheel 2, it is determined whether or not the resonance frequency W and the vibration transmission level L are equal to or higher than the first steering state threshold (S5). When it is determined that the resonance frequency W and the vibration transmission level L are not equal to or higher than the first steered state threshold, it is determined that the driver is in the light steered state in which the driver is lightly grasping the steering wheel 2 (S6). When it determines with it being a light steering state, it transfers to step S10.

  If it is determined in step S5 that the resonance frequency W and the vibration transmission level L are equal to or higher than the first steering state threshold, whether or not the resonance frequency W and the vibration transmission level L are equal to or higher than the second steering state threshold. Is determined (S7). When it is determined that the resonance frequency W and the vibration transmission level L are greater than or equal to the second steering state threshold, it is determined that the driver is in a strong steering state in which the driver is holding the steering wheel 2 strongly (S8). ). When it determines with it being a strong steering hold state, it transfers to step S10.

  On the other hand, when it is determined that the resonance frequency W and the vibration transmission level L are not equal to or higher than the second steering state threshold value, it is determined that the steering state is normal (S9). After that, in step S10, determination information regarding whether the state is a let-off state, a light steering state, a normal steering state, or a strong steering state is transmitted to various in-vehicle systems (S10). Then, it returns to step S1.

  In the steering apparatus 1 according to the first embodiment described above, vibrations of the steering wheel 2 and the steering column 3 due to traveling of the vehicle, driving of the engine, and the like are detected, and the resonance frequency of the steering wheel 2 is based on these detection results. W and vibration transmission level L are calculated. Since the resonance frequency W and vibration transmission level L of the steering wheel 2 change depending on whether the driver holds the steering wheel 2 or not, the calculated resonance frequency W and vibration transmission level L By comparing the resonance frequency W0 and the vibration transmission level L0 in the released state, it is possible to determine whether or not the steering wheel 2 is in the released state. Therefore, according to this steering device 1, it is possible to determine whether or not the vehicle is in the released state regardless of the vibration state applied to the steering wheel 2. Therefore, even when the vehicle is traveling on an uneven road surface, etc. The determination is preferably made, and thereby the reliability of the determination of the steering device 1 is improved.

[Second Embodiment]
The steering apparatus 10 according to the second embodiment is different from the first embodiment only in the function of the ECU 11. Hereinafter, the steering apparatus 10 according to the second embodiment will be described in detail with reference to the drawings.

  An ECU (calculation means, estimation means, determination means) 11 provided in the steering apparatus 10 has the same function as the ECU 6 in the first embodiment, and is detected by the first vibration sensor 4 and the second vibration sensor 5. From the result, the resonance frequency W and the vibration transmission level L are calculated.

  Further, the ECU 11 calculates the amount of change per unit time of the resonance frequency W and vibration transmission level L, and whether or not the amount of change of the calculated resonance frequency W and vibration transmission level L per unit time is equal to or greater than a predetermined threshold value. Determine whether. When the ECU 11 determines that the amount of change per unit time of the resonance frequency W and the vibration transmission level L is equal to or greater than a predetermined threshold, the ECU 11 determines that a situation has occurred in which the driver suddenly strongly tightens the steering wheel 2, and the emergency It is determined that the vehicle is in a state (for example, a pedestrian has jumped out in front of the vehicle). Here, the value of the threshold value is selected so that it can be appropriately determined whether or not it is an emergency state. When the ECU 11 determines that the state is an emergency state, the ECU 11 transmits the determination result to various in-vehicle systems. For example, when the ECU 11 transmits a determination result indicating that the vehicle is in an emergency state, these various in-vehicle systems are adapted to increase the steering yaw gain by changing the VGRS so that the vehicle can be operated quickly. Do.

  In addition, the ECU 11 estimates the driver's steering force P with respect to the steering wheel 2 based on the difference between the calculated resonance frequency W and vibration transmission level L and the hand-off state threshold. Specifically, the ECU 11 has a map that associates the resonance frequency W and the vibration transmission level L with the driver's steering force P, and estimates the steering force P based on this map. In addition, the aspect which calculates the value of the steering force P from the resonance frequency W and the vibration transmission level L by a predetermined mathematical model may be used.

  The ECU 11 determines whether or not the estimated steering force P is greater than or equal to a predetermined threshold value. When the ECU 11 determines that the estimated steering force P is greater than or equal to a predetermined threshold, the ECU 11 determines that the driver is in a driving operation tension state in which the driver is driving with tension, such as when driving on a steep winding road. . Here, the value of the threshold is selected so that it can be appropriately determined whether or not the driving operation is in a tension state. When the ECU 11 determines that the driving operation is in a tension state, the ECU 11 transmits the determination result to various in-vehicle systems. For example, when the ECU 11 transmits a determination result indicating that the vehicle is in an emergency state, the various on-vehicle systems can take measures such as increasing the steering yaw gain or increasing the steering response by changing VGRS or EPS. Do.

  Next, the operation of the ECU 11 in the steering device 10 will be specifically described with reference to the drawings.

  As shown in FIG. 3, first, the detection result of the vibration T1 of the steering wheel 2 is transmitted from the first vibration sensor 4, and the detection result of the vibration T2 of the steering column 3 is transmitted from the second vibration sensor 5. (S21). Based on these detection results, the resonance frequency W and the vibration transmission level L of the steering wheel 2 are calculated (S22).

  Subsequently, it is determined whether or not the resonance frequency W and the vibration transmission level L obtained by the calculation are equal to or greater than the let-off state threshold (S23). When it is determined that the resonance frequency W and the vibration transmission level L are not equal to or greater than the release state threshold value, it is determined that the driver is in the release state in which the steering wheel 2 is not held (S24). When it is determined that the hand is released, the process proceeds to step S30.

  On the other hand, when it is determined that the resonance frequency W and the vibration transmission level L are equal to or greater than the hand-off state threshold, it is determined that the driver is holding the steering wheel 2. When it is determined that the driver is holding the steering wheel 2, the amount of change per unit time of the resonance frequency W and the vibration transmission level L is calculated (S25).

  Thereafter, it is determined whether or not the amount of change per unit time of the resonance frequency W and the vibration transmission level L is greater than or equal to a predetermined threshold (S26). When it is determined that the amount of change per unit time of the resonance frequency W and the vibration transmission level L is greater than or equal to a predetermined threshold value, it is determined that an emergency state is present (S27). When it determines with it being an emergency state, it transfers to step S31.

  On the other hand, if it is determined that the amount of change per unit time of the resonance frequency W and the vibration transmission level L is not greater than or equal to a predetermined threshold, the steering is based on the difference between the resonance frequency W and the vibration transmission level L and the let-off state threshold A driver's steering force P for the wheel is calculated (S28). Thereafter, it is determined whether or not the estimated steering force P is equal to or greater than a predetermined threshold (S29). When it is determined that the steering holding force P is equal to or greater than the predetermined threshold value, it is determined that the driver is in a driving operation tension state in which the driver is nervous (S30). When it is determined that the driving operation is in a tension state, the process proceeds to step S31. On the other hand, when it is determined that the steering holding force P is not equal to or greater than the predetermined threshold, the process returns to step S1.

  Thereafter, in step S31, determination information regarding whether the state is a let-off state, an emergency state, a driving operation tension state, or a strong steering steady state is transmitted to various in-vehicle systems (S10). Then, it returns to step S21.

  In the steering apparatus 10 according to the second embodiment described above, when the driver is in a driving operation tension state in which the driver is driving with tension, the driver strongly holds the steering wheel 2 and the steering force P Focusing on the fact that the vehicle is often high, it is determined from the driver's steering force P whether or not the driver is in a tension state. Similarly, in this steering device 10, it is noted that in an emergency state such as when a pedestrian suddenly appears in front of the vehicle, the driver often frequently suddenly strongly grips the steering wheel 2 to resonate. And it is determined whether it is an emergency state from the variation | change_quantity for every unit time of the vibration transmission level L. FIG. In the steering device 10, various vehicle-mounted systems such as VGRS are made to function in accordance with determination results such as a driving operation tension state and an emergency state, so that the vehicle motion characteristics corresponding to the situation, such as increasing or decreasing the steering yaw gain, are obtained. Can be obtained.

  The present invention is not limited to the embodiment described above. For example, in the first embodiment, the three steered states of the light steered state, the normal steered state, and the strong steered state are determined from the resonance frequency W and the vibration transmission level L. There may be two states or four or more states. For example, when determining four or more steered states, three or more steered state threshold values may be stored in advance. Note that the steering unit described in the claims is not limited to a steering wheel having a wheel shape, and includes, for example, a substantially M-shaped handle.

  Various systems are not limited to those described above, and other examples include an AVS [Adaptive Variable Suspension system], an active stabilizer, and an ABS [Antilock Brake System].

  DESCRIPTION OF SYMBOLS 1,10 ... Steering device, 2 ... Steering wheel (steering part), 3 ... Steering column, 4 ... 1st vibration sensor, 5 ... 2nd vibration sensor, 6, 11 ... ECU (memory | storage means, estimation means, determination) means).

Claims (4)

A first vibration sensor provided in a steering unit of the vehicle and detecting vibration of the steering unit;
A second vibration sensor provided on a steering column coupled to the back surface of the steering unit and detecting vibration of the steering column;
Arithmetic means for calculating a resonance frequency and a vibration transmission level of the steering unit from detection results of the first vibration sensor and the second vibration sensor;
Storage means for storing the resonance frequency and the vibration transmission level in a release state in which the driver of the vehicle does not hold the steering unit as a release state threshold;
Determination means for determining whether or not the steering unit is in the released state based on the calculation result of the calculating means and the released state threshold value stored in the storage means;
A steering apparatus comprising: The storage means stores a plurality of steering state threshold values in which the driver's steering holding force with respect to the steering unit is changed in stages.
2. The determination unit according to claim 1, wherein the determination unit determines the steering state of the driver based on a plurality of the steering state threshold values when it is determined that the steering unit is not in the released state. The steering apparatus described. Based on the difference between the resonance frequency and the vibration transmission level calculated by the calculation means and the let-off state threshold, the estimation means further estimates the driver's steering holding force with respect to the steering unit,
3. The determination unit according to claim 1, wherein the determination unit determines that the driving operation is in a tension state when the steering force estimated by the estimation unit is equal to or greater than a predetermined threshold value. The steering device according to item.   The said determination means determines that it is an emergency state, when the variation | change_quantity per unit time of the said resonance frequency and the said vibration transmission level which the said calculation means calculated is more than a predetermined threshold value. The steering apparatus according to any one of claims 1 to 3.

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