JP6036522B2 - Electric steering control device - Google Patents

Description

  The present invention relates to an electric steering control device that controls steering characteristics by outputting an assist steering force corresponding to a steering torque applied to a handle shaft by a motor.

  As the above-mentioned electric steering control device, in order to cause the motor to generate an appropriate assist steering force according to the driver's handle operation, the motor assists based on various input signals such as a steering torque applied to the handle shaft by the driver's handle operation. A device that calculates a steering force and drives a motor based on the calculation result is known.

  In such an electric steering control device, there is one that changes a damping force according to a steering power that is a product of a steering torque and a steering speed in accordance with a steering direction (increase / return) (see, for example, Patent Document 1). ).

Japanese Patent No. 4103747

  However, in the above-described electric steering control device, although the damping force is reduced when the steering wheel is turned back, the return difficulty due to the inertial force is improved, but the sense of unity between the reaction force and the vehicle motion during gentle steering is improved. There was a problem that did not come out.

  Therefore, in view of such a problem, an object of the present invention is to enable output of an assist steering force according to a situation in an electric steering control device that assists steering with a motor.

  In the electric steering control device of the present invention configured to achieve the above object, the basic assist amount generating means generates a basic assist amount for assisting the steering operation based on the steering torque. Then, the assist compensation amount generating means converts the steering compensation amount for correcting the basic assist amount into a steering state amount that represents a physical amount capable of recognizing the state of turning and turning back the steering wheel of the vehicle, and holding the vehicle. Generate according to speed.

  Further, the assist amount correction means generates the corrected assist amount by correcting the basic assist amount with the assist compensation amount. Further, the motor driving means drives the motor based on the correction assist amount.

  According to such an electric steering control device, it is possible to satisfactorily recognize the vehicle state (traveling state, traveling environment, etc.) from the steering state amount and the traveling speed of the vehicle. Can be output.

In order to achieve the above object, the computer may be an electric steering control program for realizing each unit as an electric steering control device.
Further, the descriptions in the claims can be arbitrarily combined as much as possible. At this time, a part of the configuration may be excluded within a range where the object of the invention can be achieved.

It is a block diagram showing schematic structure of the electric power steering system of embodiment. It is a block diagram showing schematic structure of the control mechanism of ECU. It is a block diagram showing schematic structure of a load estimator. It is a block diagram showing schematic structure of a torque correction part. It is a graph which shows the map utilized when setting a gain in a damping gain calculating part. It is a graph which shows the map for damping control torque Td production | generation in a damping control part.

Embodiments according to the present invention will be described below with reference to the drawings.
[Configuration of this embodiment]
As shown in FIG. 1, the electric power steering system 1 of the present embodiment assists the operation of the handle 2 by a driver with a motor 6. The handle 2 is fixed to one end of a steering shaft 3, and a torque sensor 4 is connected to the other end of the steering shaft 3, and an intermediate shaft 5 is connected to the other end of the torque sensor 4. In the following description, the entire shaft body from the steering shaft 3 through the torque sensor 4 to the intermediate shaft 5 is also collectively referred to as a handle shaft.

  The torque sensor 4 is a sensor for detecting the steering torque Ts. Specifically, a torsion bar that connects the steering shaft 3 and the intermediate shaft 5 is provided, and a torque applied to the torsion bar is detected based on a twist angle of the torsion bar.

  The motor 6 assists the steering force of the handle 2 and its rotation is transmitted to the intermediate shaft 5 via the speed reduction mechanism 6a. That is, the speed reduction mechanism 6a is constituted by a worm gear provided at the tip of the rotating shaft of the motor 6 and a worm wheel provided coaxially with the intermediate shaft 5 in mesh with the worm gear. The rotation of the motor 6 is transmitted to the intermediate shaft 5. Conversely, when the intermediate shaft 5 is rotated by the operation of the handle 2 or the reaction force from the road surface (road surface reaction force), the rotation is transmitted to the motor 6 via the speed reduction mechanism 6a, and the motor 6 is also rotated. It will be.

  The motor 6 is a brushless motor in the present embodiment, and includes a rotation sensor such as a resolver, and is configured to output the rotation state of the motor 6. The motor 6 of the present embodiment is configured to be capable of outputting at least a motor speed ω (information indicating a rotational angular speed, which will be treated in the dimension of the rotational speed of the handle shaft) as a rotational state from the rotation sensor.

  The other end of the intermediate shaft 5 opposite to the end to which the torque sensor 4 is connected is connected to the steering gear box 7. The steering gear box 7 is configured by a gear mechanism including a rack and a pinion gear, and the rack teeth mesh with a pinion gear provided at the other end of the intermediate shaft 5. Therefore, when the driver turns the handle 2, the intermediate shaft 5 rotates (that is, the pinion gear rotates), thereby moving the rack to the left and right.

  Tie rods 8 are attached to both ends of the rack, and the tie rods 8 reciprocate left and right together with the rack. Accordingly, the tie rod 8 pulls or pushes the knuckle arm 9 ahead, thereby changing the direction of each tire 10 that is a steered wheel. A vehicle speed sensor 11 for detecting the vehicle speed V is provided at a predetermined part of the vehicle.

  With this configuration, when the driver rotates (steers) the handle 2, the rotation is transmitted to the steering gear box 7 via the steering shaft 3, the torque sensor 4, and the intermediate shaft 5. Then, in the steering gear box 7, the rotation of the intermediate shaft 5 is converted into the left-right movement of the tie rod 8, and the left and right tires 10 are steered by the movement of the tie rod 8.

  The ECU 15 is operated by electric power from a vehicle battery (not shown), and assists based on the steering torque Ts detected by the torque sensor 4, the motor speed ω of the motor 6, and the vehicle speed V detected by the vehicle speed sensor 11. Torque command Ta is calculated. Then, by applying a driving voltage Vd corresponding to the calculation result to the motor 6, the assist amount of the force that the driver turns the steering wheel 2 (and the force that steers both the tires 10) is controlled.

  In this embodiment, since the motor 6 is a brushless motor, the drive voltage Vd output (applied) from the ECU 15 to the motor 6 is specifically the three-phase (U, V, W) drive voltages Vdu, Vdv, Vdw. is there. The rotational torque of the motor 6 is controlled by applying the drive voltages Vdu, Vdv, Vdw of each phase from the ECU 15 to the motor 6 (energizing the drive current of each phase). A method for driving a brushless motor with a three-phase drive voltage (for example, PWM drive) and a drive circuit (for example, a three-phase inverter) for generating the three-phase drive voltage are well known. Omitted.

  The ECU 15 controls the motor 6 by directly controlling the drive voltage Vd applied to the motor 6, but the steering system mechanism 100 driven by the motor 6 as a result by controlling the motor 6. Therefore, the control target of the ECU 15 can be said to be the steering system mechanism 100. The steering system mechanism 100 indicates the entire mechanism excluding the ECU 15 in the system configuration diagram shown in FIG. 1, that is, the entire mechanism that transmits the steering force of the handle 2 from the handle 2 to each tire 10.

  Next, a schematic configuration (control mechanism) of the ECU 15 is shown in a block diagram of FIG. Note that, in the control mechanism of the ECU 15 shown in FIG. 2, each part except the current feedback (FB) unit 42 and part of the functions of the current FB unit 42 are actually determined by a CPU (not shown) included in the ECU 15. This is realized by executing a control program.

  That is, FIG. 2 shows various functions realized by the CPU divided into functional blocks. However, it is merely an example that the control mechanisms shown in these figures are realized by software, and the whole or a part of the control mechanism shown in FIG. 2 or the like is realized by hardware such as a logic circuit. Needless to say, it may be.

ECU15, as shown in FIG. 2, the base assist unit 20 that generates a base assist command Tb ^*, a correction unit 30 for generating a correction torque command Tr, adding the base assist command Tb ^* and the correction torque command Tr And an adder 41 for generating an assist torque command Ta, and a current feedback (FB) unit 42 for energizing and driving the motor 6 by applying a drive voltage Vd to the motor 6 based on the assist torque command Ta. .

The base assist unit 20 realizes the characteristic of the steering reaction force (steering torque) according to the road surface reaction force (road surface load), that is, the reaction (reaction force) corresponding to the road surface load is transmitted quasi-steadily to the driver. Is a block for realizing that the driver can easily understand the state of the vehicle and the state of the road surface. The load estimator 21, the target generator 22, the deviation calculator 23, the controller Part 24. That is, the base assist unit 20 is based on the steering torque Ts, and assists the operation of the steering wheel 2 so that the steering torque Ts changes according to the road surface load applied to each wheel 10 from the road surface. Tb ^* is generated.

The load estimator 21 estimates the road load based on the base assist command Tb ^* and the steering torque Ts. Based on the road load (estimated load Tx) estimated by the load estimator 21 and the traveling speed (vehicle speed V) of the host vehicle, the target generator 22 calculates a target steering torque Ts ^* that is a target value of the steering torque ^. Generate.

The target generation unit 22 makes it possible for the driver to feel that the steering operation is heavy or light according to the road surface reaction force, or the driver's steering reaction force (or steering torque) with respect to an increase in the road surface reaction force. A target steering torque Ts ^* for generating the degree of increase (gradient) is generated.

In practice, the target generator 22 of the present embodiment maps the target steering torque Ts ^* corresponding to the estimated load Tx and the vehicle speed V, and generates the target steering torque Ts ^* based on the map.

The deviation calculator 23 calculates a torque deviation which is a difference between the steering torque Ts and the target steering torque Ts ^* . The controller unit 24 is configured as a known PID controller including a differentiator, an integrator, and the like.

Based on the torque deviation (difference between the steering torque Ts and the target steering torque Ts *), the controller unit 24 makes the torque deviation zero, that is, assist steering force (also referred to as assist torque or assist amount) according to the road load. To generate a base assist command Tb ^* indicating the assist steering force.

The base assist command Tb ^* generated in this way is a torque command for generating an assist steering force according to the road load. Therefore, even if the base assist command Tb ^* is input to the current FB unit 42, It is possible to realize a characteristic of the steering reaction force according to at least the road surface load.

  On the other hand, the correction unit 30 transmits vehicle motion characteristics and steering mechanism transmission to the driver's steering operation so as to follow the driver's intention (specifically, the vehicle is properly converged or a smooth vehicle turn is generated). And a torque correction unit 31 is provided. The torque correction unit 31 generates a correction torque command Tr for suppressing (converging) the above-described unstable behavior based on the steering torque Ts and the motor speed ω.

The base assist command Tb ^* generated by the base assist unit 20 and the correction torque command Tr generated by the correction unit 30 are added by the adder 41, thereby generating an assist torque command Ta.

  Then, based on the assist torque command Ta, the electric current FB unit 42 applies a torque (assist steering force) corresponding to the assist torque command Ta to the handle shaft (particularly on the tire 10 side with respect to the torque sensor 4). A drive voltage Vd is applied to 6. Specifically, a target current (target current for each phase) to be energized to each phase of the motor 6 is set based on the assist torque command Ta. Then, by detecting and feeding back the energization current value Im of each phase and controlling the drive voltage Vd (controlling the energization current) so that the detected value (the energization current Im of each phase) matches the target current. A desired assist steering force is generated with respect to the handle shaft.

As shown in FIG. 3, the load estimator 21 includes an adder 21a that adds a base assist command Tb ^* and a steering torque Ts, and a low-pass filter (LPF) that extracts a component in a band of a predetermined frequency or less from the addition result. ) 21b, and the frequency component extracted by the LPF 21b is output as the estimated load Tx.

  Usually, the driver is driving mainly by relying on steering reaction force information of 10 Hz or less, and higher frequency components, for example, vibrations in a band of dozens of Hz to 20 Hz under the spring (around the wheel and suspension), It is known to feel uncomfortable for the driver. Therefore, in this embodiment, in order to prevent such unpleasant vibrations from being transmitted to the driver, the cutoff frequency of the LPF 21b is set to 10 Hz, and a frequency component of approximately 10 Hz or less is passed (extracted) so that a frequency component higher than 10 Hz is blocked. I have to.

  Returning to FIG. 2, the torque correction unit 31 in the correction unit 30 will be described. The torque correction unit 31 is means for realizing appropriate operation stability (appropriate vehicle motion characteristics) for the vehicle as a whole, and as shown in FIG. 4, a driver power calculation unit 32, a damping gain calculation unit 33, A damping control unit 34 and a damping integrator 35 are provided.

  The driver power calculation unit 32 calculates the product of the motor speed ω (for example, positive in the left direction) and the steering torque Ts (for example, positive in the left direction), and outputs the calculation result as the driver power W. In the present embodiment, the driver power W is used to express whether the driver's steering state is cut or returned as a continuous physical quantity.

  The driver work rate W is represented by the product of the steering torque Ts and the motor speed (converted to the handle shaft) ω, and thus takes a larger positive value as the cutting operation becomes stronger, and becomes larger as the returned strength becomes higher. It takes a value. A gain Kw (work rate sensitive gain) for changing the strength and sign of the correction torque command Tr is obtained according to the work rate.

  The damping gain calculation unit 33 outputs a gain Kw corresponding to the driver power W using a map in which the driver power W (steering state amount) and the gain Kw are associated with each other, for example, as shown in FIG. Here, in this map, a different map is selected according to the traveling speed.

The intermediate speed may be obtained by linear interpolation. The gain Kw is set to the following characteristics, for example, according to the vehicle speed range.
(1) When the vehicle is stopped, W <0, that is, a higher gain Kw when the steering wheel is in the return state (switchback).

For example, in a state where the steering wheel is turned back from the left to the right (the steering torque Ts is positive and the steering speed ω is negative), the base assist command Tb ^* is a positive value (assist to the left of the steering wheel). On the other hand, since the damping control torque Td (see FIG. 6) has a positive value, the correction torque command Tr has a positive value, which increases the assist in the left direction of the steering wheel and suppresses the return in the right direction of the steering wheel. (The brake is applied to handle operation). That is, when the hand holding the handle is loosened and returned due to this characteristic, the handle can be quickly prevented from rotating without wobbling.

(2) At an extremely low speed immediately after the start of the vehicle, a smaller gain Kw is set when W <0, and in some cases, a negative gain Kw is set.
For example, when the motor speed ω is a negative value (switching back from left to right), if the positive gain Kw is reduced, the correction torque command Tr becomes a small positive value, and the brake operation is hardly applied to the steering wheel operation. Absent. In the same case, if a negative gain Kw is set, the correction torque command Tr becomes a negative value, and the steering wheel operation becomes light in a direction that makes it easier to rotate the steering wheel to the right. That is, at an extremely low speed immediately after the start of the vehicle, the self-aligning torque per steering angle is small as a characteristic of the vehicle. Therefore, it is set as described above so as not to hinder the neutralization of the handle.

(3) When the vehicle speed increases and reaches a predetermined speed (for example, about 60 km / h), the gain Kw when W <0 is set large.
In this case, as in the case of (1) above, the brake is applied to the handle operation. In other words, when the vehicle is traveling at a speed higher than a predetermined speed, the handle tends to be returned strongly due to the strength of the self-aligning torque. Therefore, in this case, if a larger gain Kw is set than in the case of the notch (W> 0), the feeling of returning the steering wheel is reduced, and the connection (operability) of the steering force in the lane change or the like is improved. .

(4) The gain Kw is set to a value smaller than that of other driver work rate regions when the vehicle is traveling straight with the steering wheel neutral except when the vehicle is stopped, or when the vehicle is held (steered) after steering.
For example, when the motor speed ω changes from 0 to a positive value (cutting out from the state where the steering wheel is stopped), the positive gain Kw is decreased. Then, the correction torque command Tr becomes a small negative value, and the brake is hardly applied to the steering wheel operation. That is, in the region where W≈0, such as cut out from straight ahead, the damping action is small, and thus the turning behavior can be smoothly produced by configuring as described above.

  Similarly, even when cutting out from the rudder, it is possible to smoothly shift to the turning operation. In particular, during steering, the steering mechanical system has strong friction and the steering wheel is difficult to start. Therefore, the effect of smoothly shifting to turning operation is increased by using a smaller Kw.

  Next, as shown in FIG. 6, the damping control unit 34 outputs a damping control torque Td corresponding to the motor speed ω using a map in which the motor speed ω and the damping control torque Td are associated with each other.

  Here, the damping control torque Td is set according to the steering speed, and acts to stop the rotation of the steering wheel (change in the steering angle). In the map for setting the damping control torque Td, the damping control torque Td tends to increase in absolute value as the steering speed increases, but does not change at a motor speed ω (steering speed) of 500 deg / s or higher. Is set. This is to prevent the steering operation from becoming excessively heavy during sudden steering such as emergency avoidance.

Next, the damping integrator 35 generates and outputs a correction torque command Tr by multiplying the damping control torque Td by a gain corresponding to the driver power W.
[Effects of this embodiment]
In the electric power steering system 1 described in detail above, the target generator 22 generates a base assist command Tb ^* for assisting the steering operation based on the steering torque. Then, the correction unit 30 increases the steering torque amount for correcting the base assist command Tb ^* by turning the steering wheel of the vehicle, returning the correction torque command Tr, and representing the physical quantity that can recognize the state of steering and the vehicle state. Generated according to the running speed.

Further, the adder 41 generates the assist torque command Ta by correcting the base assist command Tb ^* with the correction torque command Tr. Further, the current FB unit 42 drives the motor 6 based on the assist torque command Ta.

  According to the electric power steering system 1 as described above, it is possible to satisfactorily recognize the vehicle state (traveling state, traveling environment, etc.) from the steering state amount and the traveling speed of the vehicle. Steering force can be output. Therefore, it is possible to obtain a sense of unity between the reaction force and the vehicle motion during gentle steering. That is, the connection of the vehicle motion sensation can be improved.

  In the conventional technique, for example, when the vehicle speed becomes high, the restoring force from the tire becomes strong, so that the sense of being returned becomes strong when the damping force is reduced when returning. In other words, the vehicle moves faster than the driver's intention. On the other hand, when the damping force is increased when the damping force is increased compared with the returning time, the movement of the vehicle is suppressed. That is, the movement of the vehicle tends to be delayed from the intention of the driver. Therefore, although it has been difficult to improve the connection between the vehicle motion sensation by adding back and returning, according to the configuration of the present embodiment, the connection between the vehicle motion sensation can be improved.

  Further, in the electric power steering system 1 described above, when the driver turns the steering wheel back, the correction unit 30 has a vehicle traveling speed within a reference speed range defined by the first speed and the second speed. A correction torque command Tr is generated so that the steering wheel operation becomes lighter than when the vehicle traveling speed is out of the reference speed range.

  According to the electric power steering system 1 as described above, it is possible to make the steering wheel operation lighter at the time of switching back when performing switching back, assuming the case of switching back at a relatively low speed according to the speed range. .

  Further, in the electric power steering system 1 described above, when the driver turns the steering wheel back, the correction unit 30 is when the traveling speed of the vehicle is outside the reference speed range defined by the first speed and the second speed. Compared with the case where the traveling speed of the vehicle is within the reference speed range, a correction torque command Tr for braking the steering wheel operation is generated.

  According to the electric power steering system 1 as described above, it is possible to easily match the steering angle with the traveling direction assuming that the steering angle is returned to the direction that coincides with the traveling direction during high-speed movement or when stopped.

  Further, in the electric power steering system 1 described above, the correction unit 30 sets the gain according to the damping control unit 34 that calculates the control torque according to the steering wheel operation speed, and the steering state amount of the driver and the traveling speed of the vehicle. A damping gain calculator 33 and a damping integrator 35 that uses a value obtained by multiplying the control torque by the gain as a correction torque command Tr are provided.

Then, the adder 41 adds the correction torque command Tr and the base assist command Tb ^* . When the driver turns the steering wheel back, the damping gain calculation unit 33 sets the damping control torque Td when the vehicle traveling speed is within the reference speed range compared to when the vehicle traveling speed is outside the reference speed range. The gain to be multiplied is set to a small positive value or a negative value.

According to the electric power steering system 1 as described above, when the vehicle traveling speed is within the reference speed range (relatively low speed), the damping amount (corrected torque command Tr) to be added to the base assist command Tb ^* when the steering wheel is returned. Can be reduced, and the return operation of the handle can be made light.

  Further, in the electric power steering system 1 described above, the damping gain calculator 33 corrects the gain to be multiplied by the damping control torque Td when the vehicle traveling speed is outside the reference speed range when the driver turns the steering wheel back. Set to a large value.

According to the electric power steering system 1 as described above, when the traveling speed of the vehicle is out of the reference speed range (relatively high speed or speed equivalent to stopping), the base assist command Tb ^* is corrected to the correction torque command Tr when the steering wheel is returned. Therefore, the brake to the steering wheel return operation can be increased.

  Further, in the electric power steering system 1 described above, the damping gain calculation unit 33, when making the transition from the state in which the driver stops the handle to the state in which the handle is moved, is more than in the state in which the driver is already moving the handle. The gain is set to a small value so that the correction torque command Tr becomes a small value as an absolute value.

According to such an electric power steering system 1, when the driver makes a transition from a state in which the steering wheel is stopped to a state in which the steering wheel is moved, the damping amount (correction torque command Tr) added to the base assist command Tb ^* is reduced. Therefore, the handle cutting operation can be lightened.

  That is, it is possible to improve the operability at the start of the handle operation. Further, when the driver is already moving the steering wheel, the damping amount (corrected torque command Tr) added to the base assist command Tb * is a normal value (a value larger than the value when the steering wheel is stopped). Therefore, the steering angle can be easily stopped at the angle intended by the driver.

[Other Embodiments]
The present invention is not construed as being limited by the above embodiment. Moreover, the aspect which abbreviate | omitted a part of structure of said embodiment as long as the subject could be solved is also embodiment of this invention. An aspect configured by appropriately combining the above-described plurality of embodiments is also an embodiment of the present invention. Moreover, all the aspects which can be considered in the limit which does not deviate from the essence of the invention specified only by the wording described in the claims are embodiments of the present invention. Further, the reference numerals used in the description of the above embodiments are also used in the claims as appropriate, but they are used for the purpose of facilitating the understanding of the invention according to each claim, and the invention according to each claim. It is not intended to limit the technical scope of

  For example, in the above embodiment, the motor 6 is used to assist the steering operation by the driver by outputting the assist steering force according to the steering torque applied to the steering shaft, but the present invention is not limited to this configuration. It can be employed in an electric steering device that adjusts the feeling (characteristic).

  In the present embodiment, the driver power factor W is calculated by the driver power factor calculator 32. However, the steering wheel of the vehicle is increased (the angle of the steering wheel with respect to the traveling direction of the vehicle is increased), and the vehicle is switched back (the vehicle The steering state quantity representing a physical quantity capable of recognizing the state of steering (maintaining the angle of the steering wheel with respect to the traveling direction of the vehicle) may be calculated. More specifically, the steering state quantity may have the following value.

The product of the shaft torque (for example, assist torque) acting on the handle shaft and the rotational speed of the handle shaft.
The product of a physical quantity that increases or decreases according to the rotation amount of the steering wheel or tire steering and a physical quantity that increases or decreases according to the rotation speed.

  As a specific example of the steering state quantity, in addition to the driver power W described above, for example, a value such as a product of a yaw rate and a steering speed, a product of a lateral acceleration and a steering speed, a product of a steering angle and a steering speed, or the like is adopted. Can do.

  Moreover, in the said embodiment, although the damping control part 34 output the damping control torque Td according to the motor speed (omega), it may be equipped with the inner side structure shown with the broken line of FIG. That is, a gain corresponding to the vehicle speed V is obtained using a map in which the vehicle speed V and the gain are associated, the gain and the damping control torque Td are multiplied using the control torque multiplier 53, A new damping control torque Td may be output.

  For example, a vehicle speed sensitive gain Kv may be prepared in the damping control unit 34 shown in FIG. 6 so as to correspond to the vehicle dynamics depending on the vehicle speed. Here, generally, when the vehicle speed increases, the sensitivity of the lateral movement of the vehicle with respect to the steering amount increases, and the yaw attenuation decreases. The damping control has a damping action of suppressing the rotation speed appearing on the handle shaft, and as a result, the effect of increasing the yaw damping is brought about.

For this reason, if the vehicle speed sensitive gain Kv is set so as to increase the damping control torque Td as the vehicle speed increases, yaw attenuation can be suppressed and the sensitivity of vehicle lateral movement can be suppressed.
On the other hand, when the vehicle is stopped, it is in a special state, and when the tire does not slip on the ground, the spring force of the tire rubber is a load of the steering operation. In a state where the tire is sliding from the ground, a friction load is generated that drags the tire rubber. The most necessary damping control in these states is to eliminate the vibration caused by the spring force of the tire rubber. In particular, the gain Kv is set to be a little higher so that quick convergence is achieved when the hand is released from the handle.

  Since the power factor sensitivity gain Kw is a function of the vehicle speed, this alone can absorb the vehicle speed dependency of the vehicle dynamics. However, if the vehicle speed sensitivity gain is prepared separately, the steering feel and vehicle for the operation of turning off and returning are prepared. The adjustment of yaw attenuation can be distinguished, making it much easier to fit.

[Correspondence between Configuration of Embodiment and Means of Present Invention]
The electric power steering system 1 in the above embodiment corresponds to the electric steering control device in the present invention, and the target generation unit 22 in the above embodiment corresponds to the basic assist amount in the present invention. The correction unit 30 in the above embodiment corresponds to the assist compensation amount generating means in the present invention, and the damping gain calculation unit 33 in the above embodiment corresponds to the gain setting means in the present invention.

  Further, the adder 41 in the above embodiment corresponds to the assist amount correcting means in the present invention, and the damping control unit 34 in the above embodiment corresponds to the control torque calculating means in the present invention. Further, the damping integrator 35 in the above embodiment corresponds to the assist compensation amount calculating means in the present invention, and the current FB section 42 in the above embodiment corresponds to the motor driving means in the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Electric power steering system, 2 ... Handle, 3 ... Steering shaft, 4 ... Torque sensor, 5 ... Intermediate shaft, 6 ... Motor, 6a ... Reduction mechanism, 7 ... Steering gear box, 8 ... Tie rod, 9 ... Knuckle arm DESCRIPTION OF SYMBOLS 10 ... Tire, 11 ... Vehicle speed sensor, 20 ... Base assist part, 21 ... Load estimator, 22 ... Target production | generation part, 23 ... Deviation calculator, 24 ... Controller part, 30 ... Correction part, 31 ... Torque correction part, 34 ... Damping control unit, 35 ... Damping integrator, 41 ... Adder, 42 ... Current FB unit, 100 ... Steering system mechanism.

Claims (7)

An electric steering control device (1) for controlling steering characteristics by outputting an assist steering force according to a steering torque applied to a handle shaft by a motor,
Basic assist amount generating means (22) for generating a basic assist amount for assisting the steering operation based on the steering torque;
An assist compensation amount for correcting the basic assist amount is generated in accordance with a steering state amount representing a physical amount capable of recognizing the state of turning and turning back and turning of the steering wheel of the vehicle, and the vehicle traveling speed. Assist compensation amount generating means (30);
Assist amount correction means (41) for generating a correction assist amount by correcting the basic assist amount by the assist compensation amount;
Motor driving means (42) for driving the motor based on the correction assist amount;
Equipped with a,
The assist compensation amount generation means, when the driver turns back the steering wheel, when the traveling speed of the vehicle is within a reference speed range defined by the first speed and the second speed set in advance, Compared to the case where the traveling speed is out of the reference speed range, and to generate an assist compensation amount that makes the steering wheel operation lighter than when the driver cuts the steering wheel.
Electric steering control device according to claim. The electric steering control device according to claim 1 ,
The assist compensation amount generation means, when the driver turns the steering wheel back, if the traveling speed of the vehicle is out of a reference speed range defined by the first speed and the second speed set in advance, Compared with a case where the traveling speed is within the reference speed range, an assist compensation amount for braking the steering wheel operation is generated. In the electric steering control device according to claim 1 or 2 ,
The assist compensation amount generating means assists when the driver makes the handle easier to move than when the driver is already moving the handle when the driver makes a transition from a state where the handle is stopped to a state where the handle is moved. An electric steering control device that generates a correction amount. In the electric steering control device according to any one of claims 1 to 3 ,
The assist compensation amount generating means includes
A control torque calculating means (34) for calculating a control torque according to the handle operating speed;
Gain setting means (33) for setting a gain according to the steering state quantity and the traveling speed of the vehicle;
Assist compensation amount calculation means (35) that uses the value obtained by multiplying the control torque by the gain as the assist compensation amount;
An electric steering control device comprising: In the electric steering control device according to claim 4 ,
The assist amount correcting means sets the sum of the basic assist amount and the assist compensation amount as the correction assist amount,
The gain setting means, when the driver turns the steering wheel back, if the traveling speed of the vehicle is within a reference speed range defined by a first speed and a second speed set in advance, the traveling speed of the vehicle The electric steering control device is characterized in that the gain is set to a small value or a negative value as compared with a case where is outside the reference speed range. In the electric steering control device according to claim 4 or 5 ,
The assist amount correcting means sets the sum of the basic assist amount and the assist compensation amount as the correction assist amount,
The gain setting means sets the gain to a large value when the driving speed of the vehicle is outside the reference speed range when the driver turns the steering wheel back. The electric steering control device according to any one of claims 4 to 6 ,
The assist amount correcting means sets the sum of the basic assist amount and the assist compensation amount as the correction assist amount,
The gain setting means sets the gain so that the handle becomes easier to move when the driver makes a transition from a state where the handle is stopped to a state where the handle is moved than when the driver is already moving the handle. An electric steering control device.