JP2009292233A - Compensation value acquisition method for wheel steering-angle control, and compensation method for wheel steering-angle control - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compensation value acquisition method for wheel steering-angle control, acquiring a compensation value to precisely compensate an output value from an electric steering actuator in wheel steering-angle control by totally reflecting disturbance factors such as frictions in a steering system and the lifting-up and lifting-down of a vehicle body. <P>SOLUTION: The compensation value acquisition method for wheel steering-angle control acquires data on a steering angle δ of a steering wheel 2 and the like when changing the output value τ output from the electric steering actuator 6 to the steering system, acquires static friction potential characteristics and dynamic friction potential characteristics in the steering system based on each correlation between the steering angle δ and the output value τ at the beginning and end of a change in steering angle δ data, and mathematically models the static friction potential characteristics and the dynamic friction potential characteristics in the steering system separately to thereby acquire each compensation value τc with respect to the output value τ when static friction and dynamic friction occur in the steering system. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a compensation value acquisition method in steering wheel rudder angle control and a compensation method in steering wheel rudder angle control, and in particular, a compensation value in steering wheel rudder angle control when automatically steering a steered wheel with an electric steering actuator. The present invention relates to an acquisition method and a compensation method in steering wheel steering angle control.

  For example, in lane tracking control that is being developed in the field of vehicle control, an electric steering device such as an electric power steering device is used to drive and control an electric steering actuator such as an electric motor so that the steering wheel of the host vehicle is controlled. Control the rudder angle of the steered wheels (front wheels) by rudder angle control, rack position control of the rack shaft, etc., and move the vehicle to the left and right lanes (road center line such as overtaking prohibition line, vehicle lane border, Steering wheel rudder angle control for performing steering control so as to follow a continuous line or a broken line marked on a road surface such as a lane marking that divides the roadway may be performed (see, for example, Patent Document 1).

  At that time, various methods are known as a method for controlling the steering wheel steering angle by the electric steering device, and one of them is, for example, a method called steering angle feedback control.

  For example, when steering wheel steering angle control is performed by steering wheel steering angle control and lane tracking control is performed, as shown in FIG. 20, on the center line CL of the traveling lane R of the host vehicle MC sandwiched between the lanes LL and LR. The target point M is set at a position P ahead of the host vehicle MC by a predetermined distance L, and the distance Δx between the position K and the target point M at the front position P in the course of the host vehicle MC is detected.

The target steering angle to be steered by the steering wheel 2 (see FIG. 1) of the host vehicle MC is δx, the predetermined gain is G,
δx = G · Δx (1)
1 is calculated, and a difference δx−δ between the target steering angle δx and the actual steering angle δ currently steered is fed back, for example, the steering actuator of the electric steering apparatus 1 shown in FIG. The output value (in this case, steering torque τ) of the steering actuator to be applied from the electric motor 6 to the pinion shaft 5 is determined.

に従って操舵トルクτを算出する。上記（２）式において、Ｇｐは比例ゲイン、Ｇｄは微分ゲインと呼ばれる比例定数である。 In the steering angle feedback control, a so-called PD control method may be used. For example, in the above example, in PD control, a term (so-called P term) proportional to the difference δx−δ between the target steering angle δx and the actual steering angle δ and proportional to the time derivative of the difference δx−δ. Add the terms (so-called D terms)

The steering torque τ is calculated according to In the above equation (2), Gp is a proportional constant called proportional gain, and Gd is a proportional constant called differential gain.

  When the steering angle feedback control is performed using the steering torque τ thus calculated, the steering angle δ of the steering wheel 2 ideally converges to the target steering angle δx in terms of time as shown in FIG. However, in reality, due to various disturbances, as shown in FIG. 21B, even if time elapses, it does not converge to the target rudder angle δx and has a deviation Δδ with respect to the target rudder angle δx. Often converges to a value.

  In order to avoid such a situation, so-called PID control in which the steering torque τ is calculated by adding an integral term (so-called I term) of Gi · ∫ (δx−δ) dt to the above equation (2). Are known. However, in such PID control, as is well known, if the integral gain Gi is set to a small value, the convergence speed of the rudder angle δ to the target rudder angle δx becomes slow, so immediacy is not guaranteed, and the integral When the gain Gi is set to a large value, immediacy can be obtained, but the overshoot phenomenon of the steering angle δ, that is, the steering angle δ becomes larger or smaller around the target steering angle δx, and the vibration occurs in time. Will occur.

  As described above, PID control cannot be effectively controlled particularly in a situation where real-time performance is required, such as lane tracking control based on steering wheel steering angle control. Further, in the PID control, the steering input of the steering wheel 2 by the driver is received as a disturbance in the first place, so that there is a problem that it is difficult to use for steering wheel steering angle control by steering angle control of the steering wheel.

の形で算出される。 In order to overcome these problems, instead of adding the integral term (I term) as described above, a disturbance is modeled and numerically expressed as a compensation value τc for the steering torque τ and added to the above equation (2). Various correction methods have been proposed. That is, in this case, the steering torque τ is

It is calculated in the form of

Disturbances exist in various forms, and as disturbances acting on the steering system, for example,
(A) Road surface friction (b) Friction in steering system (c) Car body lifting and lowering (d) Input from road surface and the like.

  Among these, “input from the road surface” in (d) means that the steering wheel 2 is automatically applied when the steering wheel 9 receives a force from the road surface, for example, when the steering wheel 9 is taken on a road surface or a gravel road. This is a disturbance that is caused by the influence from the road surface together with the “road friction” in (a).

  On the other hand, the above elements (b) and (c) are so-called disturbance elements independent of the road surface condition, that is, unique to the vehicle. Among them, (b) “friction in the steering system” means, as shown in FIG. 1, in the electric power steering apparatus 1 for a vehicle, for example, a universal joint 10 or a steering gear that connects between the steering shaft 4 and the pinion shaft 5. Friction that occurs in the box 7 or the like.

  Further, “carrying up of the vehicle body” in (c) usually means that in the geometry of the front suspension of the vehicle, as shown in FIG. 22, the kingpin shaft 20 that is the central axis of rotation of the steering wheel (front wheel) 9 is tilted by the kingpin. Since the steering wheel 9 rotates around the kingpin shaft 20 because it is provided so as to incline downward with an angle α, the ground contact point Pa between the steering wheel 9 and the road surface G tends to move downward. A phenomenon in which a vehicle body (not shown) is lifted by being pushed back onto the road surface G.

  Similarly, in the geometry of the vehicle front suspension, the kingpin shaft 20 serving as the central axis of rotation of the steering wheel (front wheel) 9 has a caster angle β as shown in FIG. Therefore, when the steering wheel 9 rotates around the kingpin shaft 20, the ground point Pa between the steering wheel 9 and the road surface G tends to move upward, but the weight of the vehicle body This is a phenomenon in which the vehicle body is relatively lifted down.

In the steering assist device described in Patent Document 2, a vehicle height sensor is used to detect the vehicle body lifting and lowering of (c) above, thereby estimating the vehicle front load, and a coil spring reaction force (not shown). The moment arm length with respect to the kingpin shaft 20 is estimated, and the compensation value τc (or the compensation value τc in the steering wheel steering angle control) is applied to the electric motor 6 for obtaining the steering wheel steering angle control using the estimated front load and moment arm length. It is proposed to cancel the moment around the kingpin axis 20 due to a vehicle-specific disturbance element, in this case, a coil spring reaction force.
JP 2004-199286 A JP 2005-343298 A

  However, even if the moment around the kingpin axis 20 caused by the coil spring reaction force can be canceled using the method described in Patent Document 2, a disturbance factor due to other factors cannot be reflected in the compensation value τc. . Moreover, in patent document 2, the influence by the friction in the steering system of said (b) is not reflected.

  As described above, among the disturbance elements (a) to (d), at least the elements (b) and (c) are vehicle-specific disturbance elements that are not related to the road surface condition. There is a possibility that the compensation value τc can be calculated by modeling based on. However, it is expected that it is difficult to pick up all the disturbance elements unique to the vehicle and theoretically obtain the compensation value τc by combining them to increase the amount of calculation for solving the equation of motion. Therefore, in practice, as described in Patent Document 2, only a portion that can be theoretically easily extracted is calculated to calculate the compensation value τc, or the friction in the steering system of FIG. It has been treated as.

  The inventors of the present application, as in (b) and (c) above, output values of an electric steering actuator such as an electric motor in a state in which various disturbance elements unique to the vehicle that are not related to the road surface condition are taken in comprehensively. In order to obtain a compensation value (for example, compensation value τc) for an output value in steering wheel steering angle control capable of compensating for (for example, steering torque τ), research was conducted to obtain a compensation value experimentally.

  As a result, useful knowledge about the disturbance element unique to the vehicle with respect to the output value (steering torque τ) is obtained, and the compensation value (compensation value τc) is obtained by comprehensively incorporating the disturbance elements (b) and (c) described above. The compensation value acquisition method in the steering wheel steering angle control which can be acquired was discovered. In addition, a compensation method in steering wheel steering angle control has been found that can effectively compensate for the output value of the electric steering actuator in steering wheel steering angle control by effectively utilizing the compensation value obtained by the method. .

  The present invention has been made in view of such circumstances, and the output value of the electric steering actuator in steering wheel steering angle control by comprehensively incorporating disturbance elements such as friction in the steering system and lifting and lowering of the vehicle body. An object of the present invention is to provide a compensation value acquisition method in steering wheel steering angle control that can acquire a compensation value that accurately compensates for the steering wheel. Another object of the present invention is to provide a compensation method in steering wheel steering angle control that can effectively compensate the output value of the electric steering actuator in steering wheel steering angle control using the compensation value obtained by this method. And

In order to solve the above problem, the first invention provides a compensation value acquisition method in steering wheel steering angle control,
In a vehicle that performs steering wheel steering angle control based on an output value that is output from an electric steering actuator to a steering system, the steering wheel data of the vehicle or the steering wheel that changes when the output value is changed is acquired. Data acquisition process,
Static friction potential acquisition for acquiring a static friction potential characteristic in a steering system based on a correlation between the steering angle data and the output value at that time when the steering angle data is changed from a state where the steering angle data does not change Process,
A dynamic friction potential acquisition step of acquiring a dynamic friction potential characteristic in a steering system based on a correlation between the steering angle data and the output value at that time when the steering angle data transitions from a changing state to a non-changing state; ,
Compensation value acquisition step of mathematically modeling the static friction potential characteristic and the dynamic friction potential characteristic in the steering system, respectively, and acquiring each compensation value for the output value at the time of static friction generation and dynamic friction generation in the steering system,
It is characterized by having.

According to a second aspect of the present invention, in the compensation value acquisition method in the steering wheel steering angle control of the first aspect,
In the data acquisition step, when the output value is output from the electric steering actuator to the steering system in the direction in which the steering angle increases and the direction in which the steering angle decreases, and the output value is changed in each case Obtain the data of the rudder angle that changes,
In the compensation value acquisition step, the compensation values for the output values when the static friction is generated and when the dynamic friction is generated in the steering system are acquired for the direction in which the steering angle increases and the direction in which the steering angle decreases, respectively.

  According to a third aspect of the present invention, in the method for obtaining a compensation value in steering wheel steering angle control according to the first or second aspect of the invention, in the data acquisition step, the steering wheel is placed on a turntable that is freely rotatable. It is characterized by acquiring corner data.

  According to a fourth aspect of the present invention, in the compensation value acquisition method in the steering wheel steering angle control according to any one of the first to third aspects, in the data acquisition step, the output value output from the electric steering actuator to the steering system is calculated. , Characterized by being increased or decreased at a constant rate.

  According to a fifth aspect of the invention, in the compensation value acquisition method in the steering wheel steering angle control according to any one of the first to fourth aspects of the invention, in the compensation value acquisition step, the static friction potential characteristic and the dynamic friction potential characteristic in the steering system are respectively set. It is characterized by modeling with a cubic equation.

  A sixth invention is the compensation value acquisition method in the steering wheel steering angle control according to any one of the first to fifth inventions, wherein in the compensation value acquisition step, the static friction potential characteristic and the dynamic friction potential characteristic in the steering system are respectively set. Each of the compensation values for the output value when the static friction is generated and when the dynamic friction is generated in the steering system is obtained as a characteristic map corresponding to each characteristic.

  According to a seventh aspect of the present invention, in the compensation method in the steering wheel steering angle control of the vehicle, the generation of static friction in the steering system acquired by the compensation value acquisition method in the steering wheel steering angle control according to any one of the first to sixth aspects of the invention. When the output value is compensated based on the compensation values for the output value at the time and when the dynamic friction is generated, if the time change in the steering angle of the vehicle or the steering wheel is zero, the static friction A compensation value at the time of occurrence is used, and when the time change is a value other than 0, the compensation value at the time of occurrence of dynamic friction is used for compensation.

  According to the first invention, for example, when an output value that gradually increases or decreases at a constant rate from the electric steering actuator in the steering wheel steering angle control is output to the steering system, the steering wheel and the steering wheel are stopped. The knowledge that the steering wheel and the steering angle of the steering wheel and the steering wheel to be measured change in a so-called staircase shape can be obtained.

  Therefore, it is possible to obtain information on static friction in a steering system including a universal joint by analyzing data at a point where the steering angle changes from a state where the steering angle does not change, and from a state where the steering angle changes. It is possible to obtain information on dynamic friction in the steering system by analyzing the data of the points that transition to a state that does not change. In addition, by actually placing the steering wheel of the vehicle on the turntable and determining the relationship between the steering wheel and the steering angle of the steering wheel and the output value of the electric steering actuator, Disturbance elements resulting from the geometry of the front suspension of the vehicle can be reflected in the compensation value in steering wheel steering angle control.

  Therefore, for the compensation value that compensates for the output value of the electric steering actuator in steering wheel steering angle control, the compensation value that reflects the influence of disturbance factors such as friction in the steering system and the lifting and lowering of the vehicle body at the same time is acquired. In addition, the compensation value at the time of occurrence of static friction and the compensation value at the time of occurrence of dynamic friction in the steering system can be obtained separately. In addition, it is possible to acquire a compensation value that can accurately compensate for the output value of the electric steering actuator in steering wheel steering angle control by comprehensively incorporating disturbance elements.

  According to the second aspect of the invention, in addition to the effect of the invention, the output value is output from the electric steering actuator in the direction in which the steering angle increases and decreases in the steering system to obtain the compensation value. In addition, it is possible to obtain respective compensation values for the output values at the time of static friction generation and dynamic friction generation in the steering system for each of turning the steering wheel clockwise and turning counterclockwise. It is possible to acquire a compensation value that can accurately compensate the output value of the electric steering actuator in the steering wheel steering angle control.

  According to the third invention, in addition to the effects of the above-mentioned inventions, disturbance factors caused by the geometry of the front suspension of the vehicle such as the lifting and lowering of the vehicle body are effectively reflected in the compensation value in the steering wheel steering angle control. It becomes possible.

  According to the fourth invention, in the data acquisition step, the output value output from the electric steering actuator to the steering system is increased or decreased at a constant rate to change the steering wheel and the steered wheels in a stationary state. It is possible to accurately form a state in which the state of rapidly turning repeatedly appears, and to change the steering angle of the steering wheel and the steered wheels in a stepped manner, and the effects of the above-described inventions are accurately exhibited.

  According to the fifth invention, in addition to the effects of the above inventions, when the static friction potential characteristic and the dynamic friction potential characteristic in the steering system are plotted against the steering angle of the steering wheel or the steering wheel, the steering angle is lower in the positive region. May be distributed in the shape of a curve that is convex upward or convex in the negative region (or convex upward in the region where the steering angle is positive, convex downward in the negative region). By approximating each with a cubic expression, it becomes possible to model accurately.

  According to the sixth invention, in addition to the effects of the inventions described above, the compensation values for the output values at the time of static friction generation and dynamic friction generation in the steering system are respectively acquired as characteristic maps corresponding to the characteristics. When the compensation value acquired by the compensation value acquisition method in steering wheel steering angle control is used in steering wheel steering angle control, the characteristic map to be selected according to each characteristic is switched to easily and accurately match the characteristic. The value can be extracted and used.

  According to the seventh invention, in the compensation method in the steering wheel steering angle control of the vehicle, when the time change is 0 based on the time change of the steering angle of the steering wheel or the steering wheel, the static friction is generated in the steering system. When the time change is a value other than 0, the output value of the electric steering actuator is compensated using the compensation value when the dynamic friction is generated in the steering system. It is possible to accurately select and use the respective compensation values at the time of occurrence of static friction and at the time of occurrence of dynamic friction in the steering system obtained separately by the compensation value acquisition method in FIG. Therefore, it is possible to effectively compensate the output value of the electric steering actuator in the steering wheel steering angle control using each compensation value acquired by the compensation value acquisition method in the steering wheel steering angle control.

  Embodiments of a compensation value acquisition method in steering wheel steering angle control and a compensation method in steering wheel steering angle control according to the present invention will be described below with reference to the drawings.

  Before describing the compensation value acquisition method and the like in steering wheel steering angle control according to the present embodiment, the configuration of the steering system of the vehicle that is the premise thereof will be described.

  In the present embodiment, a case where an electric steering device that applies steering torque to a steering system, particularly an electric motor of an electric power steering device, is used as an electric steering actuator that performs steering angle control on a steered wheel (front wheel). However, the electric motor is not limited to an electric motor as long as it is an electric steering actuator that can perform steering wheel steering angle control based on an output value output to a steering system. Further, an existing device may be used as the electric steering device, and it is not necessary to provide a special device or member for realizing the present invention.

  As shown in FIG. 1, the electric steering device 1 mainly includes a steering wheel 2, a steering column 3, a steering shaft 4, a pinion shaft 5, an electric motor 6 as an electric steering actuator, a steering gear box 7, a rack shaft (not shown), The steering shaft 4 and the pinion shaft 5 are connected by a universal joint 10.

  The steering column 3 is provided with a steering angle sensor 11 for measuring the steering angle δ around the axis of the steering wheel 2 or the steering shaft 4 described above. The steering angle δ measured by the steering angle sensor 11 is a predetermined value. It is transmitted to an electronic control unit (ECU) 12. The rudder angle sensor 11 may be attached at another position.

  Then, when the vehicle is started and, for example, steering wheel steering angle control for lane tracking control is activated, the electronic control unit 12 is configured to perform the above (3) based on the steering angle δ transmitted from the steering angle sensor 11. The steering torque τ is calculated according to the equation, an instruction current value for obtaining the steering torque τ is calculated, the calculated instruction current value is output to the electric motor 6 and the electric motor 6 is driven to rotate, and a predetermined steering torque is obtained. The steering wheel 2 is automatically steered by rotating the pinion shaft 5 with τ.

  1 shows a so-called pinion assist type electric power steering device in which the electric motor 6 is attached to the pinion shaft 5 as the electric steering device 1, but the electric steering device is not limited to this, and other than this. In addition, the present invention is similarly applied to other types of electric power steering devices such as a so-called column assist type in which the electric motor 6 is attached to the steering column 3 and a so-called rack assist type in which the electric motor 6 is attached to the rack shaft. The

  The electric steering device 1 is not necessarily limited to the electric power steering device as long as it can output the steering from the electric steering actuator to the steering system and can control the steering angle of the steering wheel. The mechanical connection with the wheel 9 is cut, and the electronic control unit calculates the steering angle based on the steering information of the steering wheel 2 and rotates the steering wheel to reach the steering angle. The present invention can also be applied to a steering device of a by-wire system.

  Furthermore, in the present embodiment, the steering torque τ is applied as an output value from the electric motor 6 that is an electric steering actuator to the steering system (pinion shaft 5 in the present embodiment), and a compensation value τc for the steering torque τ is acquired. However, the present invention is not limited to this, and the type of output value output from the electric steering actuator to the steering system and the content of the compensation value are appropriately determined according to the form of the electric steering actuator used.

  In the following, the steering angle δ of the steering wheel 2 is set to a positive value when the steering wheel 2 is turned clockwise as viewed from the driver with the steering neutral position being 0 °, and the steering wheel 2 is turned counterclockwise. If it does, it shall take a negative value. Also, the steering torque τ takes a positive value when the steering wheel 2 is turned clockwise as viewed from the driver, and takes a negative value when the steering wheel 2 is turned counterclockwise.

[Compensation value acquisition method in steering wheel steering angle control]
A compensation value acquisition method in steering wheel steering angle control according to the present embodiment will be described based on a flowchart shown in FIG. As shown in FIG. 2, the compensation value acquisition method in the steered wheel steering angle control according to this embodiment mainly includes a data acquisition step (step S1), a static friction potential acquisition step (step S2), and a dynamic friction potential acquisition. The process (step S3) and the compensation value acquisition process (step S4) are provided.

  In the data acquisition step (step S1), the data of the steering angle δ of the steering wheel 2 of the vehicle that changes when the steering torque τ applied to the steering system (pinion shaft 5) from the electric motor 6 that is an electric steering actuator is changed. To get to.

  Specifically, as shown in the flowchart of FIG. 3, first, the steering wheel (front wheel) 9 of the vehicle is placed on a turntable (not shown) (step S11). The turntable is disposed so as to be rotatable in the horizontal plane direction, and the friction in the rotation of the turntable is very small and can be ignored. Further, by using the turntable, the disturbance elements due to the influence from the road surface such as (a) and (d), which are disturbances acting on the steering system described above, are cut off, as in (b) and (c). It is possible to extract only the disturbance elements unique to the vehicle that are unrelated to the road surface condition and obtain a compensation value.

  Subsequently, the steering wheel 2 is steered counterclockwise, for example, and the minimum steering angle δmin that does not apply a force to steer the steering wheel 2 back with a return spring or the like, that is, the driver releases his hand from the steering wheel 2. However, the steering wheel 2 is steered to the minimum steering angle δmin at which the steering wheel 2 does not return.

  In this state, in order to turn the steering wheel 2 clockwise, the electric motor 6 is such that the steering torque τ applied from the electric motor 6 to the steering system (pinion shaft 5) gradually increases at a constant rate. Is supplied with an instruction current (step S12). The command current is given to the electric motor 6 as a ramp waveform having a small inclination output from a ramp wave generator (not shown), for example, and the steering wheel 2 takes several minutes from the minimum steering angle δmin to the maximum steering angle in the right direction. A steering torque τ is applied so as to be steered by applying.

  In this way, the steering angle δ of the steering wheel 2 measured by the steering angle sensor 11 is acquired while applying the steering torque τ increasing at a constant rate from the electric motor 6 to the steering system (step S13).

  When the steering torque τ that gradually increases at a constant rate is applied to the steering system in this way, the steering wheel 2 has a constant steering angle δ with respect to time t as shown in FIG. 4, for example. After a state in which the steering angle δ does not change at a rate and does not change for a while, the steering angle δ suddenly increases at a certain moment (that is, the steering wheel 2 is steered rapidly), and when it finishes increasing, it changes again. The state of not being continued for a while. In this way, the steering angle δ of the steering wheel 2 changes in a stepped manner.

  Then, this time, the steering wheel 2 is steered clockwise to the maximum steering angle δmax at which no return occurs. In this state, an instruction current is applied to the electric motor 6 so that the steering torque τ applied from the electric motor 6 to the steering system (pinion shaft 5) gradually decreases at a constant rate (step in FIG. 3). S12), data of the steering angle δ of the steering wheel 2 measured by the steering angle sensor 11 is acquired (step S13).

  When the data of the steering angle δ acquired in the same manner as described above is plotted against the time t, the steering angle δ of the steering wheel 2 does not decrease at a constant rate, as shown in FIG. After a state in which the angle δ does not change continues for a while, the steering angle δ suddenly decreases at a certain moment, and when the decrease is completed, data is obtained that changes in a stepped manner in which the state that does not change continues for a while.

  When the steering angle δ of the steering wheel 2 changes in a stepped manner in this way, the steering angle of the steered wheels 9 (see FIG. 1) and the rotation angle of the turntable on which the steered wheels 9 are placed also in a stepped manner. Change. That is, in a state where the steering angle δ of the steering wheel 2 does not change, the steering angle of the steering wheel 9 does not change and the turntable is stationary, and the steering angle δ of the steering wheel 2 changes rapidly (that is, the steering wheel 2 In the state of being rapidly steered, the steering angle of the steered wheels 9 is also rapidly changed (that is, the steered wheels 9 are steered rapidly), and the turntable is also quickly turned.

  Next, in the static friction potential acquisition step (step S2 in FIG. 2), the steering angle δ changes from a state where it does not change based on the stepwise data of the steering angle δ of the steering wheel 2 obtained as described above. The static friction potential characteristic in the steering system is acquired from the correlation between the steering angle δ when transitioning to the state to be performed and the steering torque τ at that time.

  Specifically, the static friction potential acquisition process is performed according to the flowchart shown in FIG. That is, first, from the graph of the steering angle δ (see FIG. 4) when the steering wheel 2 is turned in the clockwise direction from the state of turning to the left, as shown in FIG. A point where the steering angle δ transitions from a state where it does not change, that is, a point corresponding to the moment when the steering operation is started from a state where the steering wheel 2 is stationary (hereinafter referred to as an operation start point) is extracted. (Step S21 in FIG. 6).

  This operation start point is determined by the steering angle δ and the steering angle immediately before the steering wheel 2 in a stationary state, the steering shaft 4 associated therewith, the pinion shaft 5 and the like cannot withstand the increasing steering torque τ and start the steering operation. This is the point that gives torque τ. Therefore, by analyzing the operation start point, information on the static friction potential in the steering system including the universal joint 10 and the like, that is, the static friction potential of the steering system in the disturbance element of “friction in the steering system” of (b) above. Information can be obtained.

  Therefore, in the present embodiment, the obtained steering angle δ and steering torque τ at each operation start point are plotted on the steering angle-steering torque correlation plane as shown in FIG. 8 (step S22 in FIG. 6). Obtain static friction potential characteristics for clockwise turning.

  Similarly, the graph of the steering angle δ (see FIG. 5) when the steering wheel 2 is turned counterclockwise from the right-turned state is marked with a circle in FIG. As shown, each operation start point is extracted (step S21 in FIG. 6). Then, the obtained steering angle δ and steering torque τ at each operation start point are plotted on the steering angle-steering torque correlation plane (step S22 in FIG. 6) as shown in FIG. To obtain the static friction potential characteristics.

  Next, in the dynamic friction potential acquisition step (step S3 in FIG. 2), based on the step-like data of the steering angle δ of the steering wheel 2 obtained as described above, the steering angle δ is now changed. The dynamic friction potential characteristic in the steering system is obtained from the correlation between the steering angle δ at the time of transition to a state where it does not change and the steering torque τ at that time. Specifically, the dynamic friction potential acquisition process is performed according to the flowchart shown in FIG. 11, and a process similar to the static friction potential acquisition process is performed.

  In the dynamic friction potential acquisition step, first, from the graph of the steering angle δ (see FIG. 4) when the steering wheel 2 is turned clockwise from the left-turned state, a circle is marked in FIG. As shown, the point of transition from the state in which the steering angle δ changes to the state in which the change is stopped, that is, the point corresponding to the point when the steering operation is stopped from the state in which the steering wheel 2 is steered (hereinafter referred to as operation) The stop points are extracted (step S31 in FIG. 11).

  This operation stop point is the rudder immediately before the steering wheel 2 and the steering shaft 4 and the pinion shaft 5 accompanying the steering wheel 2 are unable to resist dynamic friction when they operate according to the applied steering torque τ and stop the steering operation. This is the point that gives the angle δ. Therefore, by analyzing this operation stop point, this time, information on the dynamic friction potential in the steering system including the universal joint 10 or the like, that is, the dynamic friction potential of the steering system in the disturbance element of the “friction in the steering system” of (b) above. You can get information about.

  Therefore, in the present embodiment, the obtained steering angle δ and steering torque τ at each operation stop point are plotted on the steering angle-steering torque correlation plane as shown in FIG. 13 (step S32 in FIG. 11). Get dynamic friction potential characteristics for clockwise turning.

  Similarly, in the graph of the steering angle δ (see FIG. 5) when the steering wheel 2 is turned counterclockwise from the state where the steering wheel 2 is turned to the right, a circle mark is attached to FIG. As shown, each operation stop point is extracted (step S31 in FIG. 11). Then, the obtained steering angle δ and steering torque τ at each operation stop point are plotted on a steering angle-steering torque correlation plane (step S32 in FIG. 11) as shown in FIG. To obtain the dynamic friction potential characteristics.

  In this way, from the graph of the steering angle δ that increases stepwise obtained when the steering wheel 2 is turned in the clockwise direction from the left-turned state (see FIG. 4), it is related to the clockwise turning. A static friction potential characteristic (see FIG. 8) and a dynamic friction potential characteristic (see FIG. 13) can be obtained, and the staircase shape obtained when the steering wheel 2 is turned counterclockwise from a state of turning to the right. From the graph of the decreasing steering angle δ (see FIG. 5), it is possible to obtain the static friction potential characteristic (see FIG. 10) and the dynamic friction potential characteristic (see FIG. 15) regarding the counterclockwise turning.

  The above-described static friction potential acquisition step (step S2 in FIG. 2) and dynamic friction potential acquisition step (step S3) are repeated for the same vehicle, and each operation start point obtained for every trial is on the same plane. As shown in FIG. 16, the static friction potential characteristics relating to clockwise turning are plotted so that the respective operation start points indicated by ○ in the figure are distributed in the vicinity of the characteristic curve A as shown in FIG. The Further, the static friction potential characteristics regarding the counterclockwise turning are plotted so that the respective operation start points are distributed in the vicinity of the characteristic curve B.

  Similarly, when the operation stop points obtained for all trials are collectively plotted on the same plane, as shown in FIG. 17, the dynamic friction potential characteristics regarding clockwise turning are indicated by a circle in the figure. Each operation stop point indicated by is plotted so as to be distributed in the vicinity of the characteristic curve C. Further, the dynamic friction potential characteristics regarding the counterclockwise turning are plotted so that the respective operation stop points are distributed in the vicinity of the characteristic curve D.

  Subsequently, in the compensation value acquisition step (step S4 in FIG. 2), the static friction potential characteristic (see FIG. 16) and the dynamic friction potential characteristic (see FIG. 17) in the steering system obtained in this way are respectively mathematically modeled. It has come to become.

  As shown in FIGS. 16 and 17, each operation start point for the static friction potential characteristics related to clockwise and counterclockwise turning, and each operation stop point for the dynamic friction potential characteristics related to clockwise and counterclockwise steering. Are distributed in the vicinity of each of the characteristic curves A to D, so that each can be approximated by a curve and effectively modeled.

  The characteristic curves A to D shown in FIG. 16 and FIG. 17 are actually curves obtained by approximating the steering torque τ with a cubic function having the steering angle δ of the steering wheel 2 as a variable, as shown in each figure. The distribution of each operation start point and each operation stop point is approximated by the cubic curves A to D with relatively high accuracy. Therefore, in the present embodiment, the static friction potential characteristic and the dynamic friction potential characteristic regarding the clockwise and counterclockwise turning in the steering system are respectively approximated and modeled by a cubic equation.

  It should be noted that the equations for approximating the static friction potential characteristics and the dynamic friction potential characteristics regarding the clockwise and counterclockwise turning in the steering system are not limited to the cubic expression, and are appropriately determined according to the shapes of the characteristic curves A to D. . In this embodiment, as shown in FIG. 16 and FIG. 17, the distribution of each operation start point and each operation stop point is convex downward in a region where the steering angle δ is positive and convex upward in a negative region. Therefore, it is preferable to approximate by an odd-order multi-order expression or a tangent function (tangent).

  Here, considering the operation start point again, as shown in FIGS. 7 and 9, when the steering wheel 2 is stationary at a certain steering angle δ, the predetermined steering torque τ indicated at the operation start point is When applied, the steering wheel 2 starts to steer. In other words, the steering wheel 2 that is stationary with the steering angle δ does not start turning unless the predetermined steering torque τ indicated by the operation start point is applied.

  That is, the steering torque τ indicated at the operation start point referred to here is the steering (operation) of the steering wheel 2 (and the steering shaft 4 and pinion shaft 5 associated therewith) that is stationary with the steering angle δ. Represents the compensation value τc of the steering torque τ necessary for starting the engine (that is, the compensation value τc for the output value (steering torque τ) when static friction occurs in the steering system).

  The operation stop point is similarly considered, and the steering torque τ indicated at the operation stop point is the steering wheel 2 that is steered with the steering angle δ (and the steering shaft 4 that is operating accompanying the steering wheel 4). This represents a compensation value τc of the steering torque τ necessary for continuing the turning (operation) of the pinion shaft 5 or the like (that is, a compensation value τc for the output value (steering torque τ) when dynamic friction occurs in the steering system). .

  Therefore, the characteristic curves A to D shown in FIG. 16 and FIG. 17 indicate the compensation values for the output values (steering torque τ) when the static friction and the dynamic friction are generated with respect to the clockwise and counterclockwise turning of the steering wheel 2. Each represents τc.

  In the compensation value acquisition step (step S4 in FIG. 2), as described above, the static friction potential characteristics (see FIG. 16) and the dynamic friction potential characteristics (see FIG. 17) in the steering system are mathematically expressed as characteristic curves AD. As shown in FIG. 18, the compensation values τc for the steering torque τ when the static friction is generated and when the dynamic friction is generated regarding the clockwise and counterclockwise turning of the steering wheel 2 are characteristic curves A to C, respectively. Acquired in the form of D.

  In FIG. 18, characteristic curves A and B are compensation values τc when static friction is generated with respect to clockwise and counterclockwise turning, and characteristic curves C and D are when dynamic friction is generated with respect to clockwise and counterclockwise turning. Each compensation value τc is represented.

Further, the acquired compensation value τc is held in the electronic control device 12 of the electric steering device 1 (see FIG. 1), and is used for calculating the steering torque τ according to the equation (3) in the steering angle feedback control described above. It is done. At that time, the characteristic curves A to D are used as characteristic maps corresponding to the respective characteristics, and the cubic equation τc = aδ ³ + bδ ² + cδ + d (4)
The steering angle δ of the steering wheel 2 transmitted from the steering angle sensor 11 is substituted into a characteristic curve formula adapted to each characteristic, and the compensation value τc can be calculated.

  Further, as a characteristic map corresponding to each characteristic, the steering angle δ is substituted into each cubic equation representing the characteristic curves A to D to form a table-shaped characteristic map in advance and held in the electronic control unit 12, The processing in the electronic control unit 12 may be configured to use the compensation value τc that matches each characteristic with reference to the table-like characteristic map.

  Since the operation of each step in the compensation value acquisition method in the steering wheel steering angle control according to the present embodiment has been described in the above description, the description thereof will be omitted. Among the elements (b) and (c), which are the disturbance elements unique to the vehicle, the “friction in the steering system” in (b) has been described in the above description. ) Will be described in the present embodiment.

  As described above, the vehicle body is lifted (see FIG. 22) and lowered (see FIG. 23) so that the kingpin shaft 20 serving as the central axis of rotation of the steering wheel 9 is inclined with respect to the vertical direction. It is a phenomenon that occurs because of

  In the case of the vehicle body lifting phenomenon, the steering wheel 2 is turned clockwise from the state where the steering angle of the steering wheel 9 shown in FIG. 22 is 0 ° (in this case, the steering angle δ of the steering wheel 2 is also 0 ° and the steering is neutral). When the steering wheel 9 is turned counterclockwise and the steering wheel 9 rotates rightward or leftward around the kingpin shaft 20, the ground contact point Pa between the steering wheel 9 and the road surface G tends to move downward. Therefore, the vehicle body (not shown) is lifted relatively.

  And since the big weight of a vehicle body is lifted, the force which tries to return a steering angle to a 0 degree direction is added to the steering wheel 9 conversely. At the same time, a force for returning to the steering neutral state is applied to the steering wheel 2 and the like. The more the steering wheel 2 is turned clockwise or counterclockwise, the more the steering wheel 9 tends to move downward, so that the vehicle body is relatively lifted and the return force applied to the steering wheel 9 and the steering wheel 2 is increased. growing.

  As described above, since the force for returning to the steering neutral state increases as the absolute value of the steering angle δ of the steering wheel 2 increases from 0 °, the steering torque τ to be applied from the electric motor 6 to the steering system is compensated. The magnitude of the value τc (that is, the absolute value of the compensation value τc) must be increased.

  On the other hand, in the case of the vehicle body lifting phenomenon, the vehicle body is lowered when the steering wheel 2 is turned clockwise or counterclockwise from the state where the steering angle of the steering wheel 9 shown in FIG. 23 is 0 °. On the contrary, the more the steering wheel 2 is turned clockwise or counterclockwise, the more force is applied from the vehicle body to further turn the steering wheel 2 in the same direction.

  Therefore, in this case, the steering wheel 2 automatically tries to steer in that direction as the absolute value of the steering angle δ of the steering wheel 2 departs from 0 °. The magnitude of the compensation value τc of the steering torque τ (that is, the absolute value of the compensation value τc) becomes small, or a torque in the direction opposite to that of the steering wheel 2 must be given.

  Usually, the lifting phenomenon is stronger than the lifting phenomenon. Therefore, the steering torque (compensation value τc) must be applied to the steering system from the electric steering actuator such as the electric motor 6 so as to counter the return force applied to the steering wheel 9 and the steering wheel 2 as shown in FIG. As described above, it is considered that the characteristic curves A to D with respect to the steering angle δ of the compensation value τc are generally graphs that rise to the right.

  As described above, according to the compensation value acquisition method in the steering wheel steering angle control according to the present embodiment, gradually from the electric steering actuator in the steering wheel steering angle control such as the electric motor 6 of the electric steering device 1 at a constant rate. When an output value that increases or decreases (for example, steering torque τ) is output to the steering system, the state in which the steering wheel 2 and the steering wheel 9 are stationary and the state in which the steering wheel 9 is steered repeatedly appear and are measured. The knowledge that the steering angles of the steering wheel 2 and the steering wheel 9 change in a stepwise manner is obtained.

  For this reason, in the steering angle of the steering wheel 2 or the steering wheel 9 that changes in a staircase shape, the data in the steering system including the universal joint 10 or the like is analyzed by analyzing the data of the transition point from the state in which the steering angle does not change. Information on friction can be obtained, and information on dynamic friction in the steering system can be obtained by analyzing data at a point where the steering angle changes from a state where the steering angle changes to a state where the steering angle does not change.

  Also, by actually placing the steering wheel 9 of the vehicle on the turntable and determining the relationship between the steering angle of the steering wheel 2 or the steering wheel 9 and the output value of the electric steering actuator, the vehicle body can be lifted or lifted. It is possible to reflect a disturbance element caused by the geometry of the front suspension of the vehicle such as descending in the compensation value in the steering wheel steering angle control.

  As described above, in the compensation value acquisition method in the steering wheel steering angle control according to the present embodiment, the compensation value for compensating the output value of the electric steering actuator in the steering wheel steering angle control is the friction in the steering system, the lifting of the vehicle body, and the holding value. It is possible to obtain a compensation value that reflects and reflects the influence of disturbance factors such as lowering at the same time, and separates the compensation value when static friction occurs and the compensation value when dynamic friction occurs in the steering system. It can be acquired.

  For this reason, it is possible to acquire a compensation value capable of accurately compensating for the output value of the electric steering actuator in the steering wheel steering angle control by comprehensively incorporating disturbance elements.

  In the present embodiment, the steering angle δ around the axis of the steering wheel 2 or the steering shaft 4 is measured by the steering angle sensor 11, but the steering wheel 9 is measured by measuring the turning angle of the turntable or the like. It is also possible to configure such that the characteristic of the compensation value with respect to the steering angle of the steered wheels 9 is obtained by measuring the steering angle.

  Further, it is also possible to obtain a compensation value characteristic for the rack position of the rack shaft of the vehicle instead of or together with the steering angle δ of the steering wheel 2 or the steering angle of the steering wheel 9. .

[Compensation method in steering wheel steering angle control]
Next, a compensation method in the steering wheel steering angle control that compensates the output value based on the compensation value that compensates the output value of the electric steering actuator obtained by the compensation value acquisition method in the steering wheel steering angle control described above will be described.

  In the present embodiment, as described above, the characteristic map (see FIG. 18) of the acquired compensation value τc is in the form of the cubic equation shown in the above equation (4) or in the form of a table. 1)).

  Then, when data of the steering angle δ of the steering wheel 2 measured by the steering angle sensor 11 is transmitted, the electronic control unit 12 determines the compensation value τc by referring to the characteristic map of the compensation value τc, and determines it. The calculated compensation value τc is substituted into the above equation (3), and the steering torque τ, which is an output value output from the electric motor 6 that is an electric steering actuator to the steering system (in the present embodiment, the pinion shaft 5), is calculated. In the present embodiment, the electronic control unit 12 converts the calculated steering torque τ into a command current value and rotationally drives the electric motor 6.

  In the present embodiment, in this way, the output value from the electric steering actuator (electric motor 6) to the steering system (pinion shaft 5) in the steering wheel steering angle control is compensated, and the steering wheel for lane tracking control or the like is compensated. Rudder angle control is performed.

  As described above, in the compensation value acquisition method in the steering wheel steering angle control according to the present embodiment, the compensation value τc for the output value (steering torque τ) at the time of static friction generation and dynamic friction generation in the steering system is clockwise and Obtained in connection with counterclockwise steering. Therefore, in the compensation method in the steering wheel steering angle control according to the present embodiment, they are accurately selected and used as the compensation value τc of the steering torque τ applied from the electric motor 6 to the steering system.

  In the compensation method in the steered wheel steering angle control according to the present embodiment, processing is performed according to the flowchart shown in FIG.

  The electronic control unit 12 first obtains data on the steering angle δ of the steering wheel 2 from the steering angle sensor 11 (step S51). This process is performed at a predetermined time interval Δt, and the electronic control unit 12 stores the obtained data of the steering angle δ in a storage means (not shown). When the electronic control unit 12 obtains the data of the steering angle δ of the steering wheel 2, it subsequently calculates the difference Δδ (= δnew−δold) between the steering angle data δold obtained last time and the steering angle data δnew obtained this time. Then, the time change Δδ / Δt of the steering angle δ is calculated (step S52).

  Then, the electronic control unit 12 determines whether or not the steering wheel 2 is turning clockwise based on the value of the time change Δδ / Δt of the steering angle δ (step S53), and turns clockwise. If it is determined that the vehicle is moving (step S53; YES), refer to the characteristic map (characteristic curve C) for generating dynamic friction related to clockwise turning among the characteristic maps (see FIG. 18) of the compensation value τc. (Step S54 in FIG. 19).

  If the electronic control unit 12 determines that the steering wheel 2 is not turning clockwise based on the value of the time change Δδ / Δt of the steering angle δ (step S53; NO), then the steering wheel 2 It is determined whether or not is turning counterclockwise (step S55). If it is determined that the vehicle is turning counterclockwise (step S55; YES), among the characteristic maps of the compensation value τc (see FIG. 18), the characteristic map for generating dynamic friction related to counterclockwise turning is determined. Reference is made to (characteristic curve D) (step S56 in FIG. 19).

  If the electronic control unit 12 determines that the steering wheel 2 is not turning clockwise or counterclockwise based on the value of the time change Δδ / Δt of the steering angle δ (step S55; NO), the steering It is determined that the wheel 2 is not steered.

  Then, when performing steering wheel steering angle control in lane tracking control or the like, the steering torque τ necessary for turning the steering wheel 9 at the present time, that is, the first term on the right side (P) other than the compensation value τc in the above equation (3) If the sum of the first term) and the second term (D term) is a positive value (step S57; YES), it is determined that the steering wheel 2 should be steered clockwise. Refers to the characteristic map (characteristic curve A) for generating static friction related to clockwise turning among the characteristic maps of the compensation value τc (see FIG. 18) (step S58 in FIG. 19).

  Further, the steering torque τ necessary for turning the steered wheel 9 at the present time (that is, the sum of the P term and the D term in the above expression (3)) is not a positive value (step S57; NO), but is a negative value. If so (step S59; YES), since it is determined that the steering wheel 2 should be turned counterclockwise, the electronic control unit 12 determines that each characteristic map of the compensation value τc (see FIG. 18). Reference is made to a characteristic map (characteristic curve B) for the generation of static friction related to counterclockwise turning (step S60 in FIG. 19).

  If the steering torque τ necessary for turning the steering wheel 9 at the present time is neither a positive value nor a negative value (that is, 0, step S59; NO), the steering wheel 2 is turned. Since it is determined that the situation is not necessary, the process returns to step S51.

  Subsequently, the electronic control unit 12 calculates the compensation value τc from the steering angle δ of the current steering wheel 2 obtained in step S51 based on the reference characteristic map, or the compensation corresponding to the steering angle δ from the table. The value τc is extracted and derived (step S61), and the derived compensation value τc is substituted into the above equation (3) to transfer from the electric motor 6 that is an electric steering actuator to the steering system (in the present embodiment, the pinion shaft 5). A steering torque τ that is an output value to be output is calculated (step S62).

  In the present embodiment, the electronic control unit 12 converts the calculated steering torque τ into a command current value and transmits the command current value to the electric motor 6, and rotates the electric motor 6 to provide an appropriate steering torque τ to the steering system. The steering wheel steering angle control is performed by giving the steering wheel.

  As described above, according to the compensation method in the steering wheel steering angle control according to the present embodiment, when the time change is zero based on the time change of the steering angle δ of the steering wheel 2, static friction is generated in the steering system. When the time change is a value other than 0, the output value of the electric steering actuator is compensated using the compensation value when dynamic friction is generated in the steering system. It is possible to accurately select and use each compensation value at the time of static friction generation and dynamic friction generation in the steering system acquired separately by the compensation value acquisition method in the wheel steering angle control.

  Therefore, it is possible to effectively compensate the output value of the electric steering actuator in the steering wheel steering angle control using each compensation value acquired by the compensation value acquisition method in the steering wheel steering angle control. Further, by appropriately selecting and using each compensation value τc for the output value at the time of static friction generation and dynamic friction generation regarding the clockwise and counterclockwise turning of the steering wheel 2, the steering wheel steering angle control can be more accurately performed. It becomes possible to compensate the output value of the electric steering actuator.

It is a figure which shows the structure of the steering system of the vehicle used with the compensation value acquisition method etc. in the steering wheel steering angle control which concerns on this embodiment. It is a flowchart which shows each process process of the compensation value acquisition method in the steering wheel steering angle control which concerns on this embodiment. It is a flowchart which shows the process performed at a data acquisition process. It is a graph which shows that a steering angle changes in a staircase shape when steering a steering wheel clockwise. It is a graph which shows that a steering angle changes to a staircase shape, when turning a steering wheel counterclockwise. It is a flowchart which shows the process performed at a static friction potential acquisition process. It is a graph which shows the operation | movement start point in the graph of FIG. It is a graph which shows the static friction potential characteristic regarding clockwise turning. It is a graph which shows the operation | movement start point in the graph of FIG. It is a graph which shows the static friction potential characteristic regarding counterclockwise turning. It is a flowchart which shows the process performed at a dynamic friction potential acquisition process. It is a graph which shows the operation stop point in the graph of FIG. It is a graph which shows the dynamic friction potential characteristic regarding clockwise turning. It is a graph which shows the operation stop point in the graph of FIG. It is a graph which shows the dynamic friction potential characteristic regarding counterclockwise steering. It is a graph showing the static friction potential characteristic and each characteristic curve regarding clockwise and counterclockwise turning. It is a graph showing the dynamic friction potential characteristic and each characteristic curve regarding clockwise and counterclockwise turning. It is a figure which shows each characteristic curve showing each compensation value with respect to the steering torque at the time of the static friction generation | occurrence | production and dynamic friction generation | occurrence | production regarding clockwise and counterclockwise turning. It is a flowchart which shows the process performed with the compensation method in the steering wheel steering angle control which concerns on this embodiment. It is a figure explaining the target point etc. which are set when performing lane following control. It is a graph which shows the case where the rudder angle of a steering wheel converges to the target rudder angle by (A) target rudder angle, and the case where it converges to the value which has a deviation with respect to the target rudder angle by rudder angle feedback control. It is a figure explaining the lifting phenomenon of a vehicle body. It is a figure explaining the drop-in phenomenon of a vehicle body.

Explanation of symbols

1 Electric steering device 2 Steering wheel 5 Steering system (pinion shaft)
6 Electric steering actuator (electric motor)
9 Steering wheel AD characteristics map (characteristic curve)
δ Steering angle τ Output value (steering torque)
τc compensation value

Claims (7)

In a vehicle that performs steering wheel steering angle control based on an output value that is output from an electric steering actuator to a steering system, the steering wheel data of the vehicle or the steering wheel that changes when the output value is changed is acquired. Data acquisition process,
Static friction potential acquisition for acquiring a static friction potential characteristic in a steering system based on a correlation between the steering angle data and the output value at that time when the steering angle data is changed from a state where the steering angle data does not change Process,
A dynamic friction potential acquisition step of acquiring a dynamic friction potential characteristic in a steering system based on a correlation between the steering angle data and the output value at that time when the steering angle data transitions from a changing state to a non-changing state; ,
Compensation value acquisition step of mathematically modeling the static friction potential characteristic and the dynamic friction potential characteristic in the steering system, respectively, and acquiring each compensation value for the output value at the time of static friction generation and dynamic friction generation in the steering system,
Compensation value acquisition method in steering wheel steering angle control characterized by having. In the data acquisition step, when the output value is output from the electric steering actuator to the steering system in the direction in which the steering angle increases and the direction in which the steering angle decreases, and the output value is changed in each case Obtain the data of the rudder angle that changes,
The compensation value acquisition step includes acquiring each of the compensation values for the output value when static friction is generated and when dynamic friction is generated in the steering system in a direction in which the steering angle increases and a direction in which the steering angle decreases. The compensation value acquisition method in the steering wheel steering angle control according to Item 1.   The steered wheel rudder angle control according to claim 1 or 2, wherein in the data obtaining step, the steered wheel data is obtained by placing the steered wheel on a turntable that can freely rotate. Compensation value acquisition method.   4. The data acquisition step according to claim 1, wherein the output value output from the electric steering actuator to the steering system is changed by increasing or decreasing at a constant rate. 5. The compensation value acquisition method in the steering wheel steering angle control according to the item.   The steered wheel according to any one of claims 1 to 4, wherein in the compensation value acquisition step, the static friction potential characteristic and the dynamic friction potential characteristic in the steering system are each modeled by a cubic equation. Compensation value acquisition method in rudder angle control.   In the compensation value acquisition step, the static friction potential characteristics and the dynamic friction potential characteristics in the steering system are respectively mathematically modeled, and the respective compensation values for the output values when the static friction is generated and when the dynamic friction is generated in the steering system. The compensation value acquisition method in steered wheel steering angle control according to any one of claims 1 to 5, wherein the method is acquired as a characteristic map corresponding to each characteristic. Compensation method in steering wheel steering angle control of a vehicle,
Each said compensation value with respect to the said output value at the time of static friction generation | occurrence | production in the said steering system acquired by the compensation value acquisition method in the steering wheel steering angle control as described in any one of Claims 1-6, and dynamic friction generation | occurrence | production When the output value is compensated based on the above, if the time change of the steering angle of the vehicle or the steering wheel of the vehicle is 0, the compensation value when the static friction is generated is used, and the time change is other than 0. If the value is a value of, a compensation method in steered wheel steering angle control is performed by using the compensation value when the dynamic friction is generated.

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