DE102012109324B4 - Steering assist device - Google Patents

Abstract

A steering assist apparatus comprising an actuator (15) for steering serving to impart a steering torque for preventing departure from the traffic lane to a steering mechanism (4); means (21, 51) for detecting a steering angular velocity detecting a steering angular velocity (Vh) in that an instruction value setting means (42) sets an instruction value of the guide torque (TG *) in the event of a danger of departure of the vehicle (100) from the lane, means (52) for setting a steering angular velocity threshold based on the instruction A command value of the guide torque (T *) set by the instruction value setting means (T *) sets a steering angular velocity threshold (Vh), correction means (53, 54, 55) for setting the instruction value of the command value set by the instruction value setting means (42) Guide torque (T *) corrected downwards when the - through the steering angular velocity (Vh) detection means (21, 51) is greater than the steering angular velocity threshold (Vh) set by the steering angular velocity threshold adjusting means (52) by at least a predetermined amount, and control means (46) based on on the instruction value of the guide torque (T *) after correction by the correction means (53, 54, 55) controls the actuator (15) for steering.

Description

Technical area

The present invention relates to a steering assist device for vehicles, which serves to prevent a vehicle from deviating from the lane while driving.

State of the art

There are proposals for steering assist devices which serve to prevent a vehicle from deviating from the lane while driving. As the steering assist devices of this kind, there are those which obtain information about the road surface and information about the relative position of the vehicle and the lane based on the captured images of a camera mounted on the vehicle and the steering mechanism when the vehicle threatens to deviate from the lane Add guide torque, which serves to return the vehicle in the direction in which this is prevented. The size and direction of the guide torque are determined according to the information about the relative position of the vehicle and the lane, the vehicle speed and so on.

The following documents of the prior art are known: Patent publication JP 2008-006857 A , Patent Publication JP 3 209 154 B2 and patent publication JP 4 200 943 B2 ,

The German patent application DE 10 2006 013 045 A1 describes a steering assist device in which a guide torque for tracking is turned off when the steering speed exceeds a threshold value.

From the German patent application DE 199 43 410 A1 For example, there is known a steering assisting apparatus which employs a steering actuator which serves to impart a steering off-lane deviation guide torque to a steering mechanism, a steering angular velocity detection means which detects the steering angular velocity, an instruction value setting means setting a commanding value of the guide torque to a danger of deviating the vehicle from the lane, correcting means for downwardly correcting the instruction value of the guide torque set by the instruction value setting means when the steering angular velocity detected by the steering angular velocity detecting means is at least a predetermined one Amount is greater than a steering angle speed threshold, and has a control means which, based on the command value of the guide torque after the correction by the correction means Actuator for steering controls.

Description of the invention

Problems to be solved by the invention

In a steering assist device as described above, since it is difficult to detect an inclination of the road surface from the images taken by the camera, it has not been possible to set a guide torque in consideration of the influence of an inclination of the road surface. Therefore, in the case where a vehicle is running on a road having a bank when a guide torque for returning the vehicle to the side where the road surface is lower has been added, as compared with the case of driving on a road without bank, the steering angle speed and the steering angle change amount over the guide torque larger and there is a risk that the vehicle is unstable.

The object of the present invention is to provide a steering assisting device with which it can be suppressed that, in the case where a vehicle is traveling on a road on a bank, when a guide torque for returning the vehicle to the side where the Road surface is lower, was added, the steering angle speed and the steering angle change amount are excessively large.

Means for problem solving

This object is achieved by a steering assist device according to claim 1. Further embodiments of the invention are the subject of the dependent claim.

In order to achieve the above object, the invention according to claim 1 consists of a steering assisting device comprising a steering actuator (15) for applying a steering torque (4) to prevent departure from the driving lane, means (21 , 51) for detecting the steering angular velocity which detects the steering angular velocity (Vh), an instruction value setting means (42) for setting an instruction value of the guide torque (T _G *) in case of a danger of deviation of the vehicle from the traffic lane Means (52) for adjusting the steering angular velocity threshold (Vh _th ), setting the steering angular velocity threshold (Vh _th ) based on the instruction value of the guide torque (T _G *) set by the instruction value setting means (42), correcting means (53, 54, 55) for adjusting commanded value of the guide torque (T _G *) adjusted downward when the steering angular velocity (Vh) detected by the steering angular velocity detecting means (Vh) is greater by at least a predetermined amount than that commanded by the means (52). Steering angular velocity threshold (Vh _th ) set for adjusting the steering angular velocity threshold, and control means (46) for steering the actuator (15) based on the instruction value of the guide torque (T _G *) after correction by the correction means (53, 54, 55) controls. Further, in the embodiment described below, the alphanumeric characters indicated in parenthesis indicate the corresponding constituent components, but of course the scope of the present invention is not limited to the embodiment concerned. This also applies to the following.

In the present invention, in the case where a vehicle is traveling on a banked road when a guide torque for returning the vehicle to the side where the road surface is lower has been added, the instruction value set by the instruction value setting means of the guide torque is corrected downward when the steering angular velocity detected by the steering angular velocity detecting means is larger than the steering angular velocity threshold value set by the steering angular velocity threshold adjusting means by at least a predetermined amount. Thus, it can be suppressed that, in the case where the vehicle is traveling on a banked road, when guide torque for returning the vehicle to the side where the road surface is lower has been added, the steering angular velocity and the steering angle variation amount become excessively large. This can suppress or prevent the vehicle from fluctuating.

The actuator for steering may also be the motor for steering assistance of an electronic power steering device.

list of figures

• 1 FIG. 12 is a schematic diagram showing an outline of the structure of an electronic power steering apparatus to which a steering assist apparatus according to an embodiment of the present invention has been applied.
• 2 is a block diagram showing the electrical structure of the ECU.
• 3 is an explanatory drawing for explaining the operation of the TLC calculating unit.
• 4 FIG. 15 is a diagram showing an example of setting the instruction value of the guide torque against the vehicle speed.
• 5A FIG. 12 is a diagram showing an instruction value of the guide torque for returning the vehicle to the side in the case where the command torque command value setting unit instructs. FIG the road surface is lower, has been added, shows the respective command value of the guide torque and the change of the steering torque, and
• 5B FIG. 15 is a diagram which, in the case where the command torque command value setting unit has added an instruction value of the guide torque for returning the vehicle to the side where the road surface is higher, the respective command value of the guide torque and the change in the command torque. FIG Steering torque shows.
• 6A FIG. 15 is a diagram showing an example of the adjustment of the steering angular velocity threshold value from the instruction value of the guide torque; and FIG
• 6B FIG. 15 is a graph showing an example of the gain characteristics of the steering angular velocity threshold against the vehicle speed.
• 7 FIG. 15 is a diagram showing an example of setting the gain for correcting the instruction value of the guide torque against the speed deviation.
• 8th FIG. 12 is a diagram showing an example of setting the instruction value of the assist torque against the detected steering torque. FIG.
• 9 FIG. 15 is a diagram which, in the case where the command torque setting instruction setting unit T _G * has added an instruction value of the guide torque in the direction of steering to the left to return the vehicle to the side where the road surface is lower , the instruction value of the guide torque after the correction and the change of the steering torque.

Embodiments of the invention

Hereinafter, an embodiment of the present invention will be explained in detail with reference to the accompanying drawings.

1 Fig. 12 is a schematic drawing showing an outline of the structure of an electronic power steering apparatus to which a steering assist apparatus according to an embodiment of the present invention has been applied.

The electronic power steering device 1 is equipped with a steering wheel 2 as a steering member for controlling the vehicle, a steering mechanism 4 that coupled with the rotation of this steering wheel 2 the wheels 3L and 3R deflects, and a steering assist device 5 which serves to assist the driver's steering.

The steering wheel 2 and the steering mechanism 4 are over the steering shaft 6 , the universal joint 7 , the countershaft 8th and the universal joint 9 coupled. In the vicinity of the steering shaft 6 is the steering angle sensor 21 arranged, which serves to detect the steering angle θh, the rotation angle of the steering shaft 6 represents. In the present embodiment, the rotation angle sensor 21 the amount of rotation (rotation angle) of the two reciprocal directions of the steering shaft 6 from the neutral position of the steering shaft 6 from, with the from the neutral position to the left direction of rotation z. B. is output as a positive value and the direction of the neutral position to the right rotation amount z. B. is output as a negative value.

The steering mechanism 4 indicates a to the universal joint 9 extending pinion shaft 11 , a rack shaft 12 , one in the at the front edge of the pinion shaft 11 located pinion 11a engaging rack 12a and the tie rod levers 14L and 14R , each at the paired edge parts of the rack shaft 12 over the tie rods 13L and 13R are connected to. The rack shaft 12 extends in the transverse direction of the vehicle. At the pinion shaft 11 is a torque sensor 22 provided for the detection of the steering torque Th.

When the steering wheel 2 controlled (turned), this rotation is via the steering shaft 6 etc. to the steering mechanism 4 transfer. On the steering mechanism 4 the rotation of the pinion 11a becomes a movement in the axial direction of the rack shaft 12 converted and over the respective tie rods 13L and 13R each turn the corresponding tie rod lever 14L and 14R. This will be the with the respective tie rod levers 14L and 14R coupled corresponding wheels 3L and 3R each deflected.

The steering assist device 5 Includes a coaxial with the rack shaft 12 arranged engine for steering assistance 15 and a ball screw mechanism (not shown in the drawing) representing the output torque of the steering assist motor 15 converted into a movement in the axial direction of the rack and the rack shaft 12 transfers. The steering assist motor 15 consists of a three-phase brushless motor. In the present embodiment, the motor becomes the steering assistance 15 is used as an actuator for generating a steering assist force (assist torque), and is also used as an actuator for generating a guide torque for preventing the vehicle from deviating from the lane.

In the vicinity of the engine for steering assistance 15 is a z. B. from a coordinate converter existing rotation angle sensor 23 arranged to serve the rotation angle θs of the rotor of the motor for steering assistance 15 demonstrated. If the engine is for steering assistance 15 is driven for rotation, this rotation by the ball screw mechanism in a movement in the axial direction of the rack shaft 12 transformed. Ie. the torque of the engine for steering assistance 15 becomes the steering mechanism 4 added. This turns the wheels 3L and 3R diverted.

The electronic power steering device 1 is also equipped with a vehicle speed sensor 24 for detecting the vehicle speed V, a camera mounted on the vehicle 25 , an image processing unit 26 and an ECU (Electronic Control Unit) 27 for controlling the motor for steering assistance 15 ,

The camera 25 is z. B. on the inside of the windscreen in the vehicle in a state in which it is directed forward and obliquely downwards with respect to the vehicle. The camera 25 picks up the road in front of the vehicle. The camera 25 is z. B. a CCD camera.

The image processing unit 26 recognizes based on the through the camera 25 The captured images display the paired lane boundary lines (white lines) indicating the lane on which the vehicle is traveling, and acquire information about the relative position of vehicle and lane. Among the above information about the relative position are those in 3 lateral displacement represented by D up to the lane boundary line which is in 3 Shear angles represented by φ are compared with the lane boundary line, etc. The lateral displacement up to the lane boundary line D and the shearing angle with respect to the lane boundary line φ will be explained in detail hereinafter.

In the ECU 27 be by the steering angle sensor 21 Proved steering angle θh, by the torque sensor 22 proven steering torque Th, by the rotation angle sensor 23 Proved rotational angles θs of the rotor of the motor for steering assistance 15 caused by the vehicle speed sensor 24 proven vehicle speed V and by the image processing unit 26 acquired information about the relative position (D, φ, etc.) entered.

2 is a block diagram showing the electrical structure of the ECU 27 shows.

The ECU 27 is equipped with a microcomputer 31 and a control circuit (inverter circuit) 32 that by the microcomputer 31 is controlled and the motor for steering assistance 15 electrical energy is supplied.

The microcomputer 31 is equipped with a CPU and a memory (ROM, RAM, etc.) and by executing certain programs, it takes over the function of several functional processing units. These multiple functional processing units include the TLC calculator 41 , the unit for setting the instruction value of the guide torque 42 , the unit for correcting the instruction value of the guide torque 43 , the assist torque setting instruction unit 44, the torque adding unit 45 and the feedback control unit 46 ,

The TLC calculation unit 41 calculates, based on the lateral displacement D to the lane boundary line and the shearing angle φ with respect to the lane, the estimated time to lane crossing (TLC) representing the assumed time to which the vehicle reaches the lane boundary line.

With reference to 3 For example, the lateral displacement D to the lane boundary line and the shearing angle φ to the lane are explained. In the event that the orientation of the vehicle 100 becomes the leftward direction with respect to the direction in which the lane extends, becomes the lane boundary line located on the left side of the lane 101 to the lane boundary line to be observed, and in the case where the orientation of the vehicle 100 is opposite to the direction in which the lane extends is the right direction, becomes the lane boundary line located on the right side of the lane 102 to the lane boundary line to be observed.

In the example of 3 becomes the lane boundary line located on the left side of the lane 101 to the lane boundary line to be observed. As the lateral displacement D to the lane boundary line, the distance between the corner at the front of the vehicle 100 which is on the side of the lane boundary line to be observed from the two right and left corners (in the example of FIG 3 the left corner), and the lane boundary line to be observed (in the example of FIG 3 the lane boundary line located on the left side of the lane 101 ) designated. Shear angle φ with respect to the lane is the angle formed by the center line extending in the vehicle and the lane boundary line to be observed.

The position of the corner at the front of the vehicle 100 which is on the side of the lane boundary line to be observed from the two right and left corners (in the example of FIG 3 the left corner), is labeled A. Further, the position where the vehicle advances while maintaining the present shear angle φ becomes the corner at the front of the vehicle 100 which is on the side of the lane boundary line to be observed from the two right and left corners (in the example of FIG 3 the left corner), the lane boundary line to be observed (in the example of FIG 3 reaches the lane boundary line 101) located on the left side of the lane, indicated by B. At a constant speed, the assumed time to departure from the lane TLC has the value that results when the distance L between A and B is divided by the vehicle speed V. Since the ratio L x sin φ = D exists between L and D, the assumed time to departure from the lane TLC is expressed by the following formula (1). $$\text{TLC}=\text{L}/\text{V}=\text{D}/\left(\text{V}\times \text{sin}\mathrm{\phi }\right)$$

Ie. the TLC calculation unit 41 calculates the assumed time to departure from the lane TLC based on formula (1) above. Further, the estimated time to departure from the lane TLC may also be calculated based on calculation formulas other than formula (1) above.

The unit 42 for setting the instruction value of the guide torque T _G * when evaluated by the TLC calculation unit 41 calculated estimated time to departure from the lane TLC is less than a certain threshold, the vehicle is at risk of deviating from the lane, and sets the instruction value of the guide torque T _G * based on the vehicle speed V. However, if the command value of the guide torque T _G * based on the previously set command value T _G * is not yet completed, the unit stops 42 for adjusting the instruction value of the guide torque T _G * no instruction value of the guide torque T _G * a.

4 FIG. 15 is a diagram showing an example of setting the instruction value of the guide torque against the vehicle speed.

The unit 42 for setting the instruction value of the guide torque T _G *, based on the vehicle speed V, makes a pattern of the instruction value of the guide torque T _G * with respect to time and sets the instruction value of the guide torque T _G * according to the manufactured pattern. In the present embodiment, the instruction value of the command torque T * _G, if the lane boundary line to be observed, and the lane boundary line on the right side of the lane of the motor for steering assistance 15 a steering torque is generated to a left steering, set to a positive value, and when the lane boundary line to be observed is the lane boundary line on the left side of the lane and from the engine to the steering assistance 15 a guide torque is generated to a rightward steering, set to a negative value.

The pattern of the instruction value of the guide torque T _G * with respect to time consists of a first interval in which the absolute value of the instruction value of the guide torque | T _G * | is gradually increased to the maximum value set in accordance with the vehicle speed V, a second interval in which the maximum value is held, and a third interval in which the absolute value of the instruction value of the guide torque | T _G * | is gradually reduced from the maximum value to zero. The maximum value of the absolute value of the instruction value of the guide torque | T _G * | is set to increase with increasing vehicle speed.

In the present embodiment, the length of the first interval, the second interval, and the third interval are each set in advance, and is, however large, the maximum value of the absolute value of the instruction value of the guide torque | T _G * | is fixed. Furthermore, the length of the second interval may also be such that it is changed according to the shear angle φ with respect to the traffic lane. For example, the length of the second interval may become larger the greater the absolute value of the shear angle φ with respect to the traffic lane.

The following is the unit 43 for correcting the instruction value of the guide torque T _G *. It is assumed that in the case where the vehicle is traveling on a banked road, as by the broken line Q1 in FIG 5A 1, an instruction value of the guide torque T _G * for returning the vehicle to the side where the road surface is lower has been set. In the present example, the instruction value of the guide torque T _G * becomes an instruction signal for generating a steering torque for steering left. In the case that using this instruction value of the guide torque T _G * in unmodified form, the motor for steering assistance 15 was controlled, the steering angle θh changes as the curve S1 of 5A , When this happens, as compared with the case where the vehicle is running on a non-banked road, the steering angular velocity and the steering angle variation amount become larger. If the steering angle speed and the steering angle change amount excessively increase, there is a risk that the vehicle will fluctuate.

On the other hand, it is assumed that, in the case where the vehicle is traveling on a banked road, as shown by the broken line Q2 in FIG 5B 1, an instruction value of the guide torque T _G * for returning the vehicle to the side where the road surface is higher has been set. In the present example, the instruction value of the guide torque T _G * becomes an instruction signal for generating a guide torque for steering to the right. In the case that using this instruction value of the guide torque T _G * in unmodified form, the motor for steering assistance 15 was controlled, the steering angle θh changes as the curve S2 of 5B , When this happens, as compared with the case where the vehicle is running on a non-banked road, the steering angular velocity and the steering angle variation amount become smaller.

The unit 43 for correcting the instruction value of the guide torque T _G * is used to correct the instruction value of the guide torque T _G * to suppress that, as in 5A an instruction value of the guide torque T _G * for returning the vehicle to the side where the road surface is lower has been set, the steering angular velocity and the steering angle change amount are excessively increased. Concretely corrects the unit 43 for correcting the instruction value of the guide torque T _G * in the case where the absolute value of the actual steering angular velocity is greater than the threshold value of the steering angular velocity, described below, by at least a certain amount 42 for setting the instruction value of the guide torque T _G * set instruction value of the guide torque T _G * down.

You turn to 2 back, so does the unit 43 for correcting the command value of the guide torque T _G *, a steering angular velocity calculating unit 51 , a steering angular velocity threshold adjustment unit 52 a deviation calculation unit 53 , a gain adjustment unit 54 and a gain multiplying unit 55 ,

The steering angular velocity calculation unit 51 calculated based on by the steering angle sensor 21 verified steering angle θh the steering speed Vh of the steering wheel 2. Concretely, by the steering angle sensor 21 detected steering angle θh repeatedly scanned in cycles. Then, when the steering angle θh has been sampled, the difference to the steering angle sampled in the previous cycle is obtained. By then dividing this difference by the sampling cycle, the steering angular velocity Vh is determined.

The steering angle speed threshold adjustment unit 52 represents based on the through the unit 42 for setting the instruction value of the guide torque T _G * set command value of the guide torque T _G * and by the vehicle speed sensor 24 detected vehicle speed V, the steering angle speed threshold Vh _th .

6A and 6B FIG. 15 are diagrams showing examples of the setting of the steering angular velocity threshold with respect to the instruction value of the guide torque and the vehicle speed. 6A shows the characteristics of the base value of the steering angular velocity threshold and 6B shows the vehicle speed gain, with which the according to the characteristics of 6A multiplied basis value is multiplied.

As in 6A is shown in the range in which the absolute value of the instruction value of the guide torque | T _G * | is below the specified value C, the base value of the steering angular velocity threshold value is set to correspond to the increase of the absolute value of the instruction value of the guide torque | T _G * | increases monotonically from the lower limit to the upper limit. In the range in which the absolute value of the instruction value of the guide torque | T _G * | reaches or exceeds the specified value C, the base value of the steering angular velocity threshold is fixed at the upper limit value.

Further, the vehicle speed gain to be multiplied by the base value of the steering speed threshold becomes, as in FIG 6B 4, in the area where the vehicle speed V is below the first predetermined vehicle speed V1 (eg, 60 km / h), it is fixed at the upper limit 1.0. Further, in the area where the vehicle speed V is equal to at least the second specific vehicle speed V2 that is greater than the first predetermined vehicle speed V1, the vehicle speed gain is fixed at the lower limit value (> 0). In the area where the vehicle speed is at least the first predetermined speed V1 but below the second certain speed V2, the vehicle speed gain is set to monotonically decrease in accordance with the increase in the vehicle speed V from the upper limit to the lower limit becomes. The reduction of the vehicle speed gain in the range in which the vehicle speed V corresponds to at least the first predetermined vehicle speed V1 serves to reduce the steering angle speed threshold because, when the vehicle speed V is at least a medium speed, along with the increase of the vehicle speed V for the restoring moment and the steering necessary force increases.

In this way, by multiplying the base value of the steering angular velocity threshold by the vehicle speed gain, the steering angular velocity threshold value Vh _{th is} set. However, it is also possible to use the base value of the steering angular velocity threshold unchanged as the steering angular velocity threshold Vh _th without applying the vehicle speed gain.

The deviation calculation unit 53 calculated by that of the absolute value of the by the steering angular velocity calculation unit 51 calculated steering angular velocity | Vh | by the steering angular velocity threshold adjustment unit 52 is subtracted from the adjusted steering angle speed threshold Vh _th , the speed deviation ΔVh (= | Vh | - Vh _th ).

The gain adjustment unit 54 Sets the gain G to correct the instruction value of the guide torque based on the speed deviation ΔVh. The gain multiplication unit 55 It calculates that it passes through the gain setting unit 54 set gain G for correcting the command value of the guide torque with that by the command torque value setting unit 42 multiplied command value of the guide torque T _G *, the final command value of the guide torque T _G * '.

7 FIG. 15 is a diagram showing an example of setting the gain G for correcting the instruction value of the guide torque against the speed deviation ΔVh.

In the case that the speed deviation ΔVh is small, d. H. in the case that the speed deviation ΔVh is smaller than the first predetermined value E (E> 0), the gain G is fixed at the upper limit of 1.0. In the case that the speed deviation ΔVh is large, d. H. in the case that the speed deviation ΔVh has at least the second predetermined value F (F> E), the gain G is fixed at the lower limit value (> 0). Within the range in which the speed deviation ΔVh is at least the first predetermined value E but below the second predetermined value F, the gain G is set to increase from the upper limit value to the lower limit value in accordance with the increase of the speed deviation ΔVh is monotonically reduced.

Consequently, when the absolute value of the steering angular velocity | Vh | exceeds the steering angular velocity threshold Vh _th and reaches at least the first predetermined value E, the gain G is set to a value smaller than 1.0, so that the command value of the guide torque T _G * is corrected downward.

The unit for setting the instruction value of the assist torque 44 provides based on that through the torque sensor 22 detected steering torque Th and by the vehicle speed sensor 24 detected vehicle speed V, the instruction value of the assist torque T _A *.

8th FIG. 12 is a diagram showing an example of setting the instruction value of the assist torque against the detected steering torque. FIG.

With respect to the detected steering torque Th is z. B. for the torque to the steering to the left taken a positive value and the torque for steering to the right is taken a negative value. Further, the instruction value of the assist torque T _A * becomes as if from the engine for steering assistance 15 a steering assist torque is generated to the left, set to a positive value, and when from the engine to the steering assist 15 An assist torque for steering to the right is generated, set to a negative value.

For the instruction value of the assist torque T _A *, a positive value is taken against a positive value of the detected steering torque Th, and a negative value is taken against a negative value of the detected steering torque Th. When the detected steering torque Th has a minute value in the range of -T1 to T1, the assist torque is set to zero. Further, in the range in which the detected steering torque Th is out of the range -T1 to T1, the instruction value of the assist torque T _A * is set so that its absolute value becomes larger as the absolute value of the detected steering torque Th becomes larger. Further, the instruction value of the assist torque T _A * is set so that the absolute value thereof becomes smaller as the vehicle speed sensor increases 24 proven vehicle speed V is.

The torque adding unit 45 calculates the torque command value T _M * (= T _A * + T _G * ') by passing it through the unit 44 for setting the instruction value of the assist torque T _A * set instruction value of the assist torque T _A * and that through the gain multiplication unit 55 calculated instruction value of the guide torque T _G * 'added.

In the feedback control unit 46 Be the by the torque adding unit 45 calculated torque command value T _M *, which is determined by the rotation angle sensor 23 proven Rotation angle θs of the motor for steering assistance 15 and the output signal of the current sensor 28 for detecting the presence in the steering assist motor 15 entered motor current flowing.

The feedback control unit 46 drives the control circuit 32 so on that through the engine for steering assistance 15 generated torque becomes equal to the torque command value T _M * calculated by the torque adding unit 45. Specifically, the feedback control unit drives 46 the control circuit 32 such that a current command value is calculated by the torque command value T _M * by the torque coefficient of the steering assist motor 15 is divided and the detected by the detection signal of the current sensor 28 motor current is equal to the current instruction value.

In a construction as described above, when set by the TLC calculation unit 41 calculated estimated time until the deviation from the lane TLC is less than a certain threshold value, the unit for setting the instruction value of the guide torque 42 based on the vehicle speed sensor 24 detected vehicle speed V the command value of the guide torque T _G * on. The steering angle speed threshold adjustment unit 52 sets the steering angular velocity threshold value Vh _th based on the instruction value of the guide torque T _G * and the vehicle speed V. The deviation calculation unit 53 calculates the difference between the absolute value of the steering angle speed calculation unit 51 calculated steering angular velocity | Vh | and the steering angular velocity threshold Vh _th (velocity deviation ΔVh). The gain adjustment unit 54 calculates the gain G for correcting the instruction value of the guide torque based on the speed deviation ΔVh. The gain multiplication unit 55 By multiplying the gain G for correcting the instruction value of the guide torque by the instruction value of the guide torque T _G *, the final instruction value of the guide torque T _G * 'is calculated.

Ie. when the absolute value of the actual steering angular velocity | Vh | at least by a certain amount is greater than the steering angle speed threshold Vh _th , the by the unit 42 command value of the guide torque T _G * set to set the instruction value of the guide torque T _G * is corrected downward. Thus, it can be suppressed that, in the case where the vehicle is traveling on a banked road, when an instruction value of the guide torque T _G * for returning the vehicle to the side where the road surface is lower is set, the steering angular velocity and Steering angle change amount become excessively large.

This point is made using 9 explained even more concrete. It is assumed that in the case of driving on a banked road, as shown by the dashed line Q1, through the unit 42 for setting the instruction value of the guide torque T _G *, an instruction value of the guide torque T _G * for returning the vehicle to the side where the road surface is lower has been set. In the case where the instruction value of the guide torque T _G * is not corrected, the steering angle θh drastically increases (as shown by the broken line S1) as compared with the case where the vehicle is running on a non-banked road ). As a result, there is a risk that the vehicle fluctuates.

In the present embodiment, when the absolute value of the steering angular velocity | Vh | at least by a certain amount is greater than the steering angle speed threshold Vh _th , the by the unit 42 command value of the guide torque T _G * set to set the instruction value of the guide torque T _G * is corrected downward. Therefore, the command value of the guide torque T _G * is corrected downward as shown by the solid line Q3. As a result, the steering angle θh smoothly changes as shown by the solid line S3. As a result, it can be suppressed that the vehicle fluctuates.

Above, an embodiment of the present invention has been explained, but the present invention may be embodied by other forms. For example, represent the unit 42 for setting the command value of the guide torque T _G * and the assist torque instruction value setting unit 44 respectively, an instruction value of the guide torque and an instruction value of the assist torque, but it is also possible to respectively set a current instruction value corresponding to the instruction value of the guide torque and a current instruction value corresponding to the instruction value of the assist torque.

Furthermore, in the above embodiment, the unit 42 for setting the instruction value of the guide torque T _G * based on the vehicle speed V, the instruction value of the guide torque T _G *, but it is also possible that the instruction value of the guide torque T _G * is set based on the ratio of the relative position of lane and vehicle , For example, the unit 42 for setting the instruction value of the guide torque T _G * also set an instruction value of the guide torque T _G * for decreasing the deviation amount based on the amount of deviation between the widthwise centerline of the lane and the vehicle widthwise centerline.

Further, in the above embodiment, a pattern of the instruction value of the guide torque T _G * with respect to the time as in FIG 4 shown trapezoidal, but there is no limitation, but it can be set, for example, a sine wave pattern.

Further, in the above embodiment, based on the assumed time to departure from the lane TLC, a timing for setting the instruction value of the guide torque T _G * (timing for performing the lane departure prevention control) is determined, but the timing for adjustment The instruction value of the guide torque T _G * may also be determined based on information other than the presumed time until the deviation from the lane TLC.

In addition, it is possible to carry out various design changes within the scope of the claims.

LIST OF REFERENCE NUMBERS

1

electronic power steering device

2

steering wheel

3L, 3R

bikes

4

steering mechanism

5

Steering assist device

6

steering shaft

7

universal joint

8th

Countershaft

9

universal joint

11

pinion shaft

11a

pinion

12

Rack shaft

12a

rack

13L, 13R

turnbuckles

14L, 14R

Knuckle arm

15

Engine for steering assistance

21

Steering angle sensor

22

torque sensor

23

Rotation angle sensor

24

Vehicle speed sensor

25

camera

26

Image processing unit

27

ECU

31

microcomputer

32

control circuit

41

TLC calculation unit

42

Unit (means) for setting the instruction value of the guide torque

43

Unit (means) for correcting the instruction value of the guide torque

44

Unit (means) for setting the instruction value of the assist torque

45

Torque addition unit

46

Feedback control unit

51

Steering angle velocity calculation unit

52

Steering angular velocity threshold adjustment unit

53

Deviation calculation unit

54

Gain adjustment unit

55

Gain multiplication unit

100

vehicle

101

lane boundary line located on the left side of the lane

102

lane boundary line located on the right side of the lane

Claims (2)

A steering assist device comprising an actuator (15) for steering, which serves to supply a steering mechanism (4) with a guide torque for preventing departure from the traffic lane, means (21, 51) for detecting a steering angular velocity which detects a steering angular velocity (Vh), means (42) for setting an instruction value which, in the event of a risk of departure of the vehicle (100) from the driving lane, an instruction value of the guiding torque ( TG *), steering angular velocity threshold setting means (52) for setting a steering angular velocity threshold (Vh _th ) based on the command value of guide torque (T _G *) set by said instruction value setting means (42), correcting means (53 54, 55) which downwardly corrects the instruction value of the guide torque (T _G *) set by the instruction value setting means (42) when the steering angular velocity (Vh ) at least by a certain amount greater than that by the means (52) for E steering angle speed threshold value (Vh _th ), and control means (46) based on the instruction value of the guide torque (T _G *) after correction by the correcting means (53, 54, 55) drive the actuator (15) controls. Steering support device according to Claim 1 characterized in that the actuator (15) for steering is the motor for steering assistance of an electronic power steering device (1).

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