JP3891575B2 - Driver steering state estimator and electric steering apparatus using the same - Google Patents

Description

  The present invention relates to a driver steering state estimator for estimating a state in which a driver is operating a steering wheel in order to control an electric steering device such as an electric power steering device mounted on an automobile or the like, and an electric steering device using the same About.

In an electric steering device (hereinafter also referred to as electric power steering) mounted on a vehicle such as an automobile, in order to improve driving feeling in steering operation and obtain appropriate steering performance, what is the current steering state? It is necessary to accurately detect whether it is in a state. In the present invention, a device having such a function is called a driver steering state estimator. In the driver steering state estimator used in the conventional electric steering apparatus, the driver puts the steering wheel on the steering wheel in order to determine whether the driver's steering state is the forward state (the steering wheel increasing operation state) or the returning state (the steering wheel returning operation state). Japanese Patent Application Laid-Open No. H10-228561 discloses a method for determining the applied steering torque and the sign of the rotational speed signal of the motor that assists the steering wheel.
However, in the technique disclosed in Patent Document 1, since the determination is made based on the sign (rotation direction) of the motor speed signal and the sign of the steering torque signal, the problem is that the motor speed or the steering torque cannot be accurately determined near zero. was there.

  In addition, when using a brushed motor widely used in electric power steering, it is difficult to obtain an accurate motor speed signal directly from the motor terminal unless a rotational speed sensor is provided separately. Japanese Patent Application Laid-Open No. H10-228707 discloses a method for estimating the motor speed by performing correction based on the motor current. However, since this method does not directly detect rotation, there is a possibility that the motor speed sign (rotation direction) cannot be detected accurately.

Patent Document 3 discloses a method for determining whether a steering wheel is cut or returned based on the direction of increase or decrease in absolute value of road surface reaction torque. However, in this technique, since the determination is made based on the direction in which the absolute value of the road surface reaction torque increases and decreases, there is a problem that the determination cannot be made accurately when the change in the road surface reaction torque is very small.
JP-A-8-67266 Japanese Patent Laid-Open No. 11-139339 JP 2002-294441 A

In the conventional electric steering device and the driver steering state estimator used therefor, the determination of the steering state is performed based on the sign (rotation direction) of the motor speed signal and the sign of the steering torque signal. There was a problem that the steering state could not be accurately determined near zero.
Further, in the case of obtaining a rotation signal by correcting the motor terminal voltage, since the rotation is not a directly detected value, the sign (rotation direction) of the motor speed cannot be accurately detected, and the accurate steering state cannot be determined. There was a problem.
In addition, in the case of determining the steering state by the direction of increase and decrease of the absolute value of the road surface reaction torque, there is a case that the determination of the state may not be accurate when the change of the road surface reaction torque is very small. was there.

  The present invention has been made to solve the above problems, and when the motor speed value cannot be obtained accurately or when the direction of increase and decrease in the absolute value of the road surface reaction force torque cannot be obtained. The present invention also aims to provide a driver steering state estimator capable of accurately estimating the steering state such as whether the steering state of the driver is a cut state or a returning state, and an electric steering apparatus provided with the driver steering state estimator. To do.

A driver steering state estimator according to the present invention is a road surface reaction force torque detector that detects road surface reaction torque generated on a wheel in response to a steering operation received by a vehicle steering mechanism from a driver of the vehicle,
A steering shaft reaction force torque detector for detecting a steering shaft reaction force torque generated in the steering shaft in accordance with the steering operation;
A friction torque generator that stores in advance a predetermined value as a friction torque of the steering mechanism;
A first state determiner that compares the absolute value of the steering shaft reaction force torque with the absolute value of the friction torque;
A second state determiner for comparing the absolute value of the steering shaft reaction force torque with the absolute value of the road surface reaction force torque;
A steering state determiner that estimates whether the steering operation is a steering wheel turning-up state or a steering wheel return state based on the determination result of the first state determination unit and the determination result of the second state determination result It is equipped with.

An electric steering apparatus for a vehicle according to the present invention includes a steering mechanism having an electric motor connected to a handle shaft and generating a steering force.
The aforementioned driver steering state estimator,
A damping compensator in which a damping compensation amount is controlled based on a steering wheel steering state estimated by the driver steering state estimator;
At least an assist torque determination block for calculating the torque generated by the motor by adding the outputs of the damping compensator is provided.

The driver steering state estimator of the present invention estimates the driver's steering state using the nonlinearity due to friction and the hysteresis due to the phase delay without using the speed signal of the assist motor, so that the motor speed value can be obtained accurately. Even in the case where the driver is not able to do so, it is possible to accurately estimate the steering state such as whether the driver's steering state is the cut state or the return state.
Moreover, since the electric steering apparatus of the present invention includes the driver steering state estimator that does not use the motor speed, the steering apparatus can have a better driving feeling than the conventional one.

Embodiment 1 FIG.
Hereinafter, an electric steering apparatus 100 according to Embodiment 1 of the present invention will be described with reference to the drawings.
FIG. 1 shows an overall configuration when an electric steering apparatus 100 according to Embodiment 1 of the present invention is installed in a vehicle.
The electric steering device 100 is attached to a steering mechanism (also referred to as a steering mechanism) 10 of the vehicle. The steering mechanism 10 includes a handle 1, a steering shaft 2, a steering gear box 3, a rack and pinion mechanism 6, and a tire 7.
The electric steering device 100 includes a torque sensor 4 attached to the steering shaft 2, an assist motor 5 attached to the steering shaft 2 (hereinafter also simply referred to as a motor), a control unit 8 for controlling the assist motor 5, and a cable connecting them. . Of course, the power supply unit is also included, but it is obvious, so the description is omitted here.
In FIG. 1, a handle 1 is a steering handle that is steered by a driver of an automobile, and is attached to an upper end of a steering shaft 2. Steering torque (indicated by Thdl) applied by the driver's arm is applied to the steering wheel 1. This steering torque Thdl is transmitted to the steering shaft 2. The torque sensor 4 is coupled to the steering shaft 2 and generates a steering torque detection signal Thdl (s) corresponding to the steering torque Thdl. The assist motor 5 is an electric motor, which is also coupled to the steering shaft 2 via a reduction gear (not shown), and applies an assist torque Tassist that assists the steering torque Thdl to the steering shaft 2.

The steering gear box 3 is provided at the lower end of the steering shaft 2. A combined torque obtained by adding the steering torque Thdl and the assist torque Tassist applied to the steering shaft 2 passes through the steering gear box 3 and a rack and pinion mechanism (not shown) in the steering gear box 3 to the tire 7 via the drive shaft 6. Manipulate the direction.
The electric steering apparatus 100 in FIG. 1 includes an ECU (Control Unit for Electric Power Steering) 8 (hereinafter referred to as a control unit or ECU) that is electrically combined with the steering mechanism 10. The control unit 8 receives a steering torque detection signal Thdl (s) from the torque sensor 4, a motor drive current detection signal Imtr (s) from the assist motor 5, and a motor drive voltage detection signal Vmtr (s). The The control unit 8 supplies a control signal Imtr (t) to the assist motor 5. This control signal Imtr (t) is a drive current target value for the assist motor 5.

The overall operation of FIG. 1 will be described.
In FIG. 1, the symbol Talign is a road surface reaction torque applied to the tire 7, and Ttran is a steering shaft reaction torque that acts on the steering shaft 2 based on the road surface reaction torque Talign. The steering shaft reaction force torque Ttran is a road surface reaction force torque converted to the steering shaft 2. Tfrp is the friction torque of the steering shaft mechanism 10 excluding the friction torque Tmfric of the assist motor 5.
1 detects the steering torque Thdl when the driver turns the steering wheel 1 as a steering torque detection signal Thdl (s) by the torque sensor 4, and responds to the steering torque detection signal Thdl (s). The main function is to generate an assist torque Tassist that assists the steering torque Thdl.
The control unit 8 includes a detection signal Imtr (s) that detects the drive current Imtr of the assist motor 5, a detection signal Vmtr (s) that detects the drive voltage Vmtr of the assist motor 5, and a steering torque detection signal Thdl (s). Based on the above, a current command signal Imtr (s) for generating the assist torque Tassist is calculated, and this signal Imtr (s) is supplied to the assist motor 5.

Dynamically, the sum of the steering torque Thdl and the assist torque Tassist rotates the steering shaft 2 against the steering shaft reaction torque Ttran. Further, when the handle 1 is rotated, the inertia term of the assist motor 5 also acts, so that the steering shaft reaction torque Ttran is given by the following equation (1).
T _tran = T _hdl + T _assist −J · dω / dt (1)

However, the inertia torque of the assist motor is J · dω / dt.
The assist torque Tassist by the assist motor 5 is given by the following equation (2).
T _assist = G _geaar・ K _t・ I _mtr (2)

Here, Ggear is the gear ratio of the reduction gear between the assist motor 5 and the steering shaft 2. Kt is a torque multiplier of the assist motor 5.
The steering shaft reaction torque Ttran is the sum of the road surface reaction torque Talign and the total friction torque Tfric in the steering mechanism 10, and is given by the following equation (3).

However, Tmfric is the friction torque of the assist motor 5, Tfrp is the friction torque of the steering mechanism 10 excluding the friction torque Tmfric of the assist motor 5, and Tmfric + Tfrp = Tfric.
The control unit 8 of the electric steering apparatus 100 calculates a target value for the drive current Imtr of the assist motor 5 and generates a control signal Imtr (t). Current control is performed so that the actual drive current Imtr of the assist motor 5 matches the control signal Imtr (t), and the assist motor 5 has a torque constant and a gear ratio (the distance between the assist motor 5 and the steering shaft 2). ) Is multiplied to assist the steering torque Thdl when the driver steers.

FIG. 2 is a block diagram showing a circuit of the control unit 8 of FIG. 1 and a control circuit of the assist motor 5 (not shown in FIG. 1 but built in the assist motor 5). The control unit 8 includes a vehicle speed detector 11, a steering torque detector 12, a road surface reaction force torque detector 13, a steering shaft reaction force torque detector 14, a motor speed detector 15, a motor acceleration detector 16, A driver steering state estimator 17, an assist torque determination block 18, and a motor current determiner 19 are included.
The vehicle speed detector 11 receives the vehicle speed V and outputs a vehicle speed signal V (s). The steering torque detector 12 includes a torque sensor 4 and receives a steering torque Thdl and outputs a steering torque detection signal Thdl (s).
The road surface reaction torque detector 13 receives the road surface reaction torque Talign and outputs a road surface reaction torque signal Talign (s). The steering shaft reaction force torque detector 14 receives the steering shaft reaction force torque Ttran and outputs a steering shaft reaction force torque signal Ttran (s). The motor speed detector 15 receives the rotational speed of the assist motor 5 and outputs a motor speed signal Smtr (s). The motor acceleration detector 16 differentiates the motor speed signal Smtr (s) and outputs a motor acceleration signal Amtr (s).
The detection means of the road surface reaction force torque detector 13 is detection means such as a load cell provided in the tire 7, for example, which receives the road surface reaction force torque Talign and outputs a road surface reaction force torque signal Talign (s) proportional thereto. The detection means of the steering shaft reaction force torque detector 14 is detection means such as a load cell provided on the steering shaft 2, for example, and receives the steering shaft reaction force torque Ttran and is proportional to the steering shaft reaction force torque signal Ttran (s). Is output.

The driver steering state estimator 17 receives the road surface reaction force torque signal Talign (s) and the steering shaft reaction force torque signal Ttran (s) and outputs a driver steering state estimation value Sdrv (s) (details will be described later). The assist torque determination block 18 includes a vehicle speed signal V (s), a steering torque signal Thdl (s), a road surface reaction force torque signal Talign (s), a motor speed signal Smtr (s), and a motor acceleration signal Amtr (s). ) And the driver steering state estimated value Sdrv (s), an assist torque signal Tassist (s) corresponding to the assist torque Tassist to be generated by the assist motor is generated. The motor current determiner 19 receives the assist torque signal Tassist (s) and outputs a current target value Imtr (t) for the motor drive current for generating the assist torque Tassist.
The control circuit of the assist motor 5 is built in the assist motor 5 and includes a comparator (also referred to as a subtractor or adder) 21, a motor driver 22, and a motor current detector 23. The motor current detector 23 outputs a motor drive current signal Imtr (s) corresponding to the actual drive current Imtr to the rotor 20 of the assist motor 5. The comparator 21 compares the current target value Imtr (t) with the motor drive current signal Imtr (s) and inputs the difference to the motor driver 22. The motor driver 22 drives the rotor 20 so that the difference between the target current value Imtr (t) and the drive current signal Imtr (s) is zero.

  Next, before describing the operation of the driver steering state estimator 17, the characteristics of the road surface reaction force torque and the steering shaft reaction force torque, which are the basis of the operation, will be described with reference to FIG. Steering is performed in various patterns, and the friction Tfric torque of the steering mechanism 10 also determines the direction of the friction depending on the steering direction of the driver, and is added at the time of cutting and subtracted at the time of returning. That is, the road surface reaction force torque Talign including the hysteresis characteristic corresponding to the friction torque Tfric of the steering mechanism 10 corresponds to the steering shaft reaction force torque Ttran. After all, the function of the driver steering state estimator 17 is to estimate the current position on the characteristic line of FIG.

FIG. 4 is a block diagram showing details of the driver steering state estimator 17. The driver steering state estimator 17 outputs a friction torque signal Tfric (s) corresponding to the friction torque Tfric of the steering mechanism 10 and an absolute value Ttran (s0) of the steering shaft reaction force torque signal Ttran (s). ), An absolute value calculator 26 that outputs the absolute value Talign (s0) of the road surface reaction force torque signal Talign (s), a first state determiner 27 and a second A state determination unit 28 and a steering state determination unit 29 are provided.
The first state determiner 27 generates Tfric (s) corresponding to the friction torque Tfric of the steering shaft mechanism (actually storing a predetermined constant value as the friction torque) and the output of the friction torque signal device 24. , Receiving the output of the absolute value calculator 25 that outputs the absolute value Ttran (s0) of the steering shaft reaction force torque signal Ttran (s), making a first determination of the driver steering state, and a first driver steering state determination signal Outputs Sdrv1 (s). For example, the first state determiner 27 compares the size of Tfric (s) with the size of Ttran (s0), and when Ttran (s0) is large, Sdrv1 (s) = 1, and the others are Sdrv1 (s) = 0. Output.

The second state determiner 28 outputs the absolute value calculator 25 that outputs the absolute value Ttran (s0) of the steering shaft reaction force torque signal Ttran (s) and the absolute value Talign () of the road surface reaction force torque signal Talign (s). The output of the absolute value calculator 26 that outputs s0) is received, the second determination of the driver steering state is performed, and the second driver steering state determination signal Sdrv2 (s) is output. For example, the size of Talign (s0) is compared with the size of Ttran (s0), and when Ttran (s0) is large, Sdrv2 (s) = 1 is output and the others are output as Sdrv2 (s) = 0.
The steering state determiner 29 receives the first driver steering state determination signal Sdrv1 (s) and the second driver steering state determination signal Sdrv2 (s), determines the driver's steering state, and determines the steering state determination signal Sdrv ( s) is output.
For example, when Sdrv1 (s) = 1 and Sdrv2 (s) = 1, Sdrv (s) = 1 and the others are output as Sdrv (s) = 0. This will be described again in the description of the flow of FIG. 5 below.

Next, the operation in which the driver steering state estimator 17 in FIG. 4 estimates the driver steering state will be described based on the flowchart in FIG. FIG. 5 includes steps S101 to S106 between the start and the end. First, in step S101, the absolute value Ttran (s0) of the steering shaft reaction force torque signal Ttran (s) is calculated by the steering shaft reaction force torque absolute value calculator 24, and the microcomputer memory (not shown) constituting the control unit 8 is calculated. ). In the next step S102, the road surface reaction force torque absolute value calculator 25 calculates the absolute value Talign (s0) of the road surface reaction force torque signal Talign (s) and stores it in the memory (same as above) of the microcomputer constituting the control unit 8. Read.
In the next step S103, the output Tfric (s) corresponding to the friction torque Tfric of the steering mechanism 10 is compared with the output Ttran (s0) of the steering shaft reaction torque absolute value calculator 24. Then, by determining whether or not the steering shaft reaction force torque signal is larger, the first driver steering state determination signal Sdrv1 (s) is calculated. In the next step S104, the output Ttran (s0) of the steering shaft reaction force torque absolute value calculator 24 and the output Talign (s0) of the road surface reaction force torque absolute value calculator 25 are compared, and the steering shaft reaction force torque absolute value calculator 25 is compared. By determining whether or not the force torque signal is larger, the second driver steering state determination signal Sdrv2 (s) is calculated.

The next steps S105 and S106 show the operation of the steering state determiner 29. In step S105, when it is determined that the first driver steering state determination signal Sdrv1 (s) is returned (the result of S103 is NO), it is determined that the second driver steering state determination signal Sdrv2 (s) is returned. In the case (the result of S104 is NO), the steering state determiner 29 outputs a signal that determines that the driver steering state signal Sdrv (s) is in the return state. In step S106, when it is determined that the first driver steering state determination signal Sdrv1 (s) is cut (the result of S103 is YES), the second driver steering state determination signal Sdrv2 (s) is determined to be cut. In the case (the result of S104 is YES), the steering state determiner 29 outputs a signal that determines that the driver steering state signal Sdrv (s) is in the cut state.
Thus, the driver steering state estimator 17 of the present embodiment does not need to use the speed signal of the assist motor 5 in determining the steering state.

  FIG. 6 is a block diagram showing details of the assist torque determination block 18 of FIG. 2, and also shows the effect of the present embodiment using the driver steering state signal Sdrv (s). The assist map compensator 30 receives the output V (s) of the vehicle speed detector 11 and the output Thdl (s) of the steering torque detector 12, and outputs an assist map compensation torque map (s). The damping compensator 31 receives the output V (s) of the vehicle speed detector 11, the output Sdrv (s) of the driver steering state estimator 17, and the output Smtr (s) of the motor speed detector 15, and receives a damping compensation amount torque. damp (s) is output (the details of the calculation at this time will be described later). The inertia compensator 32 receives the output V (s) of the vehicle speed detector 11 and the output Amtr (s) of the motor speed detector 16 and outputs an inertia compensation torque inner (s). The return compensator 33 receives the output V (s) of the vehicle speed detector 11 and the output Talign (s) of the road surface reaction force torque detector 13 and outputs a return compensation torque ret (s). The adder 34 also outputs the output map (s) of the assist map compensator 30, the output damp (s) of the damping compensator 31, the output iner (s) of the inertia compensator 32, and the output ret of the return compensator 33. Add (s) and output assist torque Tassist (s).

Here, FIG. 6 is described as a typical configuration example of the assist torque determination block 18, but other than the compensation elements shown in FIG. 6, known compensation elements such as friction compensation may be added. The same applies to the case where other compensators are provided because the configuration does not change because only the state quantity added by the adder 34 increases.
In FIG. 6, the output Sdrv (s) of the driver steering state estimator 17 is applied to the damping compensator 31. Here, when the output Sdrv (s) of the driver steering state estimator 17 estimates that the driver is turning the steering wheel, the output of the damping compensator 31 is decreased. As a result, when the steering wheel is cut, the steering does not become heavy, and an unnecessary increase in steering torque can be prevented.

  FIG. 7 shows an example of the steering angle-steering torque characteristics shown in FIGS. The horizontal axis is the steering angle (deg), and the vertical axis is the steering torque (Nm). A dotted line characteristic T1 indicates a steering angle-steering torque characteristic when the output Sdrv (s) of the driver steering state estimator 17 is not applied to the damping compensator 31, and a solid line characteristic T2 indicates the driver steering state estimator 17. The steering angle-steering torque characteristic when the output Sdrv (s) is applied to the damping compensator 31 and the output is controlled as described above is shown. As shown in FIG. 7, by applying the driver steering state estimator 17 to the damping compensator 31, the torque when turning the steering wheel is reduced, the steering is lightened, and an unnecessary increase in the steering wheel torque can be prevented. ing.

  In the first embodiment, it has been described that the steering shaft reaction force torque can be realized by measuring its state quantity by attaching a detector such as a load cell to the steering shaft column. However, such a detector is not necessarily used. However, for example, the control unit 8 of the electric steering apparatus is often provided with a current detector and a steering torque detector, and when it has a motor angular velocity detector, the microcomputer constituting the control unit 8 uses the formula (2). It is also possible to calculate the steering shaft reaction force torque.

  Further, even when the control unit 8 of the electric steering apparatus does not have a motor angular velocity detector, the motor angular velocity can be obtained by the following equation as proposed in Patent Document 2 described above.

  (4) where R is the motor coil resistance, L is the motor inductance, Vt is the motor applied voltage, Ve is the motor back electromotive voltage, ω is the motor angular velocity, and Kb is the feedback gain due to the motor back electromotive voltage. . The equation (4) allows the motor angular speed to be calculated even when the control unit 8 of the electric power steering control device does not have a motor speed detector.

Embodiment 2. FIG.
In the electric steering apparatus 100 of the first embodiment, the output Sdrv (s) of the driver steering state estimator 17 is applied to the damping compensator 31, whereas in the second embodiment, the output Sdrv (s) of the driver steering state estimator 17 is applied. ) Is applied to the return compensator 33. Other configurations are the same. In the following embodiments, all the methods described in the first embodiment can be applied to the steering shaft reaction force torque, the motor angular velocity, and the road surface reaction force torque, unless otherwise specified.
FIG. 8 is a block diagram showing the assist torque determination block 18 in the control device of the second embodiment, and is also a block diagram showing the effect of the present embodiment using the driver steering state signal Sdrv (s). In the present embodiment, the return compensator 33 includes the output Sdrv () of the driver steering state estimator 17 in addition to the output V (s) of the vehicle speed detector 11 and the output Talign (s) of the road surface reaction force torque detector 13. In response to s), the return compensation torque ret (s) is output.

As described above, the second embodiment applies the output Sdrv (s) of the driver steering state estimator 17 to the return compensator 33, and outputs the output of the return compensator 33 when the driver estimates that the steering wheel is cut. By making it small, the steering does not become heavy when the steering wheel is cut, and an unnecessary increase in steering torque can be prevented.
FIG. 9 shows an example of the steering angle-steering torque characteristic according to the second embodiment. The horizontal axis is the steering angle (deg), and the vertical axis is the steering torque (Nm). A thick chain line characteristic T3 indicates a steering angle-steering torque characteristic when the output Sdrv (s) of the driver steering state estimator is not applied to the return compensator 33, and a thin solid line characteristic T4 indicates a driver steering state estimator. The steering angle-steering torque characteristic when the output Sdrv (s) is applied to the return compensator 33 is shown. As shown in FIG. 9, by applying the driver steering state estimator to the return compensator, the steering does not become heavy when the steering wheel is cut, and an unnecessary increase in steering torque can be prevented.

  In the first embodiment and the second embodiment, the configuration for changing the assist torque to which the output Sdrv (s) of the driver steering state estimator 17 is applied is shown. However, the driver steering state estimator 17 is also applied to other compensators. By applying the output Sdrv (s), the assist torque can be changed. In the following embodiments, the output Sdrv (s) of the driver steering state estimator 17 can be applied to any compensator in the assist torque determination block 18.

Embodiment 3 FIG.
FIG. 10 is a block diagram showing details of the driver steering state estimator 117 in the third embodiment. In the configurations of the first embodiment and the second embodiment, the output of the friction torque signal generator 24 that generates Tfric (s) corresponding to the friction torque Tfric of the steering shaft mechanism is a constant value. In the driver steering state estimator 117, a block that generates Tfric (s) corresponding to the friction torque Tfric of the steering shaft mechanism is a friction torque signal generator 35 that changes according to the vehicle speed, and the friction torque changes according to the vehicle speed. It is configured to do.
In general, the friction torque of the steering shaft mechanism is a constant value, but as the vehicle speed increases, the hysteresis width of the steering shaft reaction force torque with respect to the road surface reaction force torque becomes smaller due to the dither torque effect due to tire rotation. The friction torque appears to decrease.
As described above, according to the third embodiment, by using the value output from the friction torque map of the steering shaft mechanism according to the change in the vehicle speed, it is possible to determine the driver steering state with high accuracy even in the region where the vehicle speed is high. It becomes.

Embodiment 4 FIG.
Next, the estimation of the driver steering state according to the fourth embodiment will be described based on the characteristics of the normative yaw rate and the actual yaw rate described in FIG. Steering is performed in various patterns, but the vehicle yaw rate has a phase lag with respect to the steering operation. That is, the vehicle yaw rate Yact corresponds to the yaw rate equivalent Yhys generated in the vehicle when the reference yaw rate Yref is zero with respect to the reference yaw rate Yref without phase delay with respect to the steering wheel angle.
FIG. 12 is a block diagram showing details of the driver steering state estimator 217 according to the fourth embodiment.
The control unit 8 includes a yaw rate detector 36 and a steering angle detector 37. The yaw rate detector 36 receives the yaw rate Yaw and outputs a yaw rate signal Yact (s). The steering angle detector 37 receives the steering angle Theta and outputs a steering angle detection signal Theta (s).
The driver steering state estimator 17 receives an absolute value calculator 38 that outputs the absolute value Yact (s0) of the yaw rate signal Yact (s), and receives the vehicle speed signal V (s) to generate a reference yaw rate gain signal Kyaw (s). A standard yaw rate gain calculator 40 for outputting, a standard yaw rate calculator 39 for receiving a steering angle detection signal Theta (s) and a standard yaw rate gain signal Kyaw (s) and outputting a standard yaw rate signal Yref (s), a standard yaw rate signal And an absolute value calculator 42 for outputting an absolute value Yref (s0) of Yref (s).

  The third state determiner 43 outputs the output of the yaw rate hysteresis amount signal device 41 that generates Yhis (s) corresponding to the yaw rate Yhys generated in the vehicle when the reference yaw rate Yref is zero, and the absolute value of the yaw rate signal Yact (s). The output of the absolute value calculator 38 that outputs Yact (s0) is received, the third driver steering state determination is performed, and the third driver steering state determination signal Sdrv3 (s) is output. For example, the third state comparator 43 compares the magnitude of Thys (s) with the magnitude of Yact (s0), and when Yact (s0) is large, Sdrv3 (s) = 1, and the others are Sdrv3 (s) = 0. Is output.

  The fourth state determiner 44 outputs the output of the absolute value calculator 38 that outputs the absolute value Yact (s0) of the yaw rate signal Yact (s) and the absolute value Yref (s0) of the reference yaw rate signal Yref (s). The output of the absolute value calculator 42 is received, the fourth driver steering state determination is performed, and the fourth driver steering state determination signal Sdrv4 (s) is output. For example, the size of Yref (s0) is compared with the size of Yact (s0), and when Yact (s0) is large, Sdrv4 (s) = 1 is output and the others are output as Sdrv4 (s) = 0.

The steering state determiner 45 receives the third driver steering state determination signal Sdrv3 (s) and the fourth driver steering state determination signal Sdrv4 (s), determines the driver's steering state, and determines the steering state determination signal Sdrv ( s) is output. For example, when Sdrv3 (s) = 1 and Sdrv4 (s) = 1, Sdrv (s) = 1 and the others are output as Sdrv (s) = 0.
In the fourth embodiment, the reference yaw rate and the actual yaw rate have been described as examples. However, since the present embodiment is a method using a phase delay, for example, steering torque, vehicle lateral G, vehicle side slip angle, vehicle A cornering force or the like can be implemented in the same manner.
As described above, according to the fourth embodiment, the steering state of the driver can be estimated even in a system having a small friction and a small hysteresis width by using the hysteresis accompanying the phase delay.

It is a figure which shows the whole structure of a typical vehicle steering system. It is a block diagram which shows the control apparatus of Embodiment 1 of this invention. It is a figure which shows the relationship between the steering axial reaction force of a typical vehicle steering device system, and a road surface reaction force. It is a block diagram of the driver steering state estimator according to Embodiment 1 of the present invention. The flowchart figure which shows the operation | movement which concerns on Embodiment 1 of this invention. It is a block diagram of the assist torque determination block which concerns on Embodiment 1 of this invention. It is a figure which shows the Lissajous waveform of the steering angle and steering torque which show the effect of Embodiment 1 of this invention. It is a block diagram of the assist torque determination block which concerns on Embodiment 2 of this invention. It is a figure which shows the Lissajous waveform of the steering angle and steering torque which show the effect of Embodiment 2 of this invention. It is a block diagram of the driver steering state estimator which concerns on Embodiment 3 of this invention. It is a figure which shows the relationship between the yaw rate of a typical vehicle steering device system, and a reference | standard yaw rate. It is a block diagram of the driver steering state estimator which concerns on Embodiment 4 of this invention.

Explanation of symbols

1 steering wheel, 2 steering shaft, 3 steering gear box,
4 Torque sensor, 5 Assist motor, 6 Rack and pinion shaft,
7 tires, 7 control unit, 8 control device,
10 steering mechanism (steering mechanism), 11 vehicle speed detector,
12 steering torque detector, 13 road surface reaction torque detector,
14 steering shaft reaction force torque detector, 15 motor speed detector,
16 motor acceleration detector,
17, 117, 217 Driver steering state estimator,
18 assist torque determination block, 19 motor current determiner,
20 rotor, 21 comparator (subtractor),
22 motor driver, 23 motor current detector,
24 Friction torque signal of steering function,
25, 26, 38, 42 absolute value calculator, 27 first state determiner,
28 Second state determiner 29, 45 Steering state determiner,
30 assist map compensator, 31 damping compensator,
32 inertia compensator, 33 return compensator, 34 adder,
35 Friction torque signal of steering shaft mechanism according to vehicle speed,
36 yaw rate detector, 37 steering angle detector,
39 standard yaw rate calculator, 40 standard yaw rate gain calculator,
41 Yaw rate hysteresis amount signal device, 43 Third state determination device,
44 4th state determination device, 100 Electric steering device.

Claims (7)

A road surface reaction force torque detector for detecting a road surface reaction force torque generated on a wheel in accordance with a steering operation received by a vehicle steering mechanism from a driver of the vehicle;
A steering shaft reaction force torque detector for detecting a steering shaft reaction force torque generated in the steering shaft in accordance with the steering operation;
A friction torque generator that stores in advance a predetermined value as a friction torque of the steering mechanism;
A first state determiner that compares the absolute value of the steering shaft reaction force torque with the absolute value of the friction torque;
A second state determiner for comparing the absolute value of the steering shaft reaction force torque with the absolute value of the road surface reaction force torque;
A steering state determiner that estimates whether the steering operation is a steering wheel turning-up state or a steering wheel return state based on the determination result of the first state determination unit and the determination result of the second state determination result A driver steering state estimator comprising: A normative yaw rate calculator for determining a normative yaw rate by multiplying a steering wheel angle generated by a steering operation of the vehicle from a driver of the vehicle by a steady gain,
A yaw rate detector for obtaining an actual yaw rate generated in the vehicle in accordance with the steering operation;
A yaw rate hysteresis amount setting device for giving in advance a yaw rate hysteresis amount generated in the vehicle when the reference yaw rate is zero;
A third state determiner for comparing the absolute value of the actual yaw rate with the absolute value of the yaw rate hysteresis amount;
A fourth state determiner that compares the absolute value of the actual yaw rate with the absolute value of the reference yaw rate;
A steering state determiner that estimates whether the steering operation is a steering wheel increase state or a steering wheel return state based on the determination result of the third state determination unit and the determination result of the fourth state determination result A driver steering state estimator comprising:   An electric steering apparatus for a vehicle comprising the driver steering state estimator according to claim 1. A steering mechanism having an electric motor coupled to the handle shaft and generating a steering force;
The driver steering state estimator according to claim 1 or 2,
A damping compensator in which a damping compensation amount is controlled based on a steering wheel steering state estimated by the driver steering state estimator;
An electric steering apparatus for a vehicle, comprising: an assist torque determining block for calculating a torque generated by the electric motor by adding at least the output of the damping compensator.   The electric steering apparatus for a vehicle according to claim 4, wherein the damping compensator is configured to increase the amount of damping compensation when an operating angular velocity of the steering wheel increases. A steering mechanism having an electric motor coupled to the handle shaft and generating a steering force;
The driver steering state estimator according to claim 1 or 2,
A return compensator in which a return compensation amount is controlled based on a steering wheel steering state estimated by the driver steering state estimator;
An electric steering apparatus for a vehicle, comprising: an assist torque determination block for calculating a torque generated by the electric motor by adding at least the output of the return compensator.   The driver steering state estimator according to claim 1, further comprising a vehicle speed detector for detecting a vehicle speed, wherein a value output from the friction torque generator is changed according to a vehicle speed of the vehicle.

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