JP3706669B2 - Vehicle steering system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle steering apparatus.
[0002]
[Prior art]
As a vehicle steering device, the present applicant has proposed a technique for causing a moving body such as a vehicle to follow a target route with a smooth trajectory in, for example, Japanese Patent Laid-Open No. 5-197423.
[0003]
[Problems to be solved by the invention]
The above-described conventional technology relates to a so-called “automatic driving vehicle” for automatically maneuvering a vehicle. However, before the technology of the autonomous driving vehicle matures and spreads, it is possible to drive a person through a visual sensor or a radar while driving. It is expected that a man-machine cooperation type vehicle steering device that travels while predicting the road conditions ahead will be realized.
[0004]
As one of such man-machine cooperative vehicle steering devices, the present applicant previously described in Japanese Patent Application No. 7-31070, while using a visual means such as a camera while driving on the road, A technique for detecting a relationship with a vehicle, outputting a command for traveling along a lane to a steering device of the vehicle, and continuously traveling along the lane is proposed.
[0005]
When this concept is put into practical use, if the actuator for power steering that is already widely used as a steering device can be used as an actuator for lane tracking control, the entire device can be designed to be small and light, Its reliability is easy to secure.
[0006]
Accordingly, a first object of the present invention is to propose an electric power steering actuator or the like as a lane following control actuator or the like, and thus to propose a small and light vehicle steering apparatus with high reliability. is there.
[0007]
Furthermore, when the target power steering is an electric type and the control algorithm is realized exclusively using a software method, a control algorithm for lane following driving, a control algorithm for power assist, Can be handled independently, it is convenient in designing and managing each of them, so that development is facilitated and reliability in actual use can be increased.
[0008]
Therefore, the second object of the present invention is to separate and describe and manage the control algorithm for lane guidance and the control algorithm as mere power steering, thereby facilitating development and configuration. An object of the present invention is to propose a vehicle steering apparatus that is simple and increases the reliability of the entire apparatus.
[0009]
Furthermore, the lane following function is generally used when the traveling speed is relatively high, such as when driving on a highway, whereas the function as a power steering, in other words, the power assist function is essentially a low speed traveling. Sometimes useful. The above logic can be understood because the power assist amount is purposely reduced during high-speed driving so that the steering force during driving does not become too light. From this viewpoint, the two control algorithms of lane tracking and power steering function can be further separated.
[0010]
Therefore, the third object of the present invention is to manage power steering control and lane tracking control by separating them completely in time, thereby maintaining the reliability of power steering control cultivated over many years. An object of the present invention is to propose a steering apparatus for a vehicle that can be held, and thus further improves the reliability of the entire apparatus.
[0011]
[Means for Solving the Problems]
In order to achieve the above-described object, first means for detecting the lane condition of the traveling road ahead, second means for detecting the movement state of the own vehicle, and outputs of the first and second means Depending on the output of the third means for calculating the steering amount necessary for maintaining the positional relationship of the host vehicle with respect to the forward road lane, the steering means for operating the steering wheel of the vehicle, and the output of the third means The steering means includes an urging means for generating a first steering torque, and a steering force detection means for detecting a second steering torque applied to the steering wheel, and outputs the steering force detection means. Accordingly, in the vehicle steering apparatus configured to drive the urging means in a direction in which the second steering torque applied to the steering wheel is decreased, the vehicle steering apparatus is configured such that the steering means includes the first steering means. 1 steering torque A first control algorithm for generating, provided with a second control algorithm for driving the urging means in a direction to reduce the second steering torque, the first control algorithm Operation amount determined by And the second control algorithm Operation amount determined by The Addition do it The biasing means is driven based on the obtained addition operation amount It was configured as follows.
[0012]
[Action]
A biasing means for generating the first steering torque in the steering means according to the output of the third means is provided, and the steering torque applied to the steering wheel is reduced in accordance with the output of the steering force detection means. In the vehicle steering apparatus configured to drive the urging means, the vehicle steering apparatus uses a first control algorithm for causing the steering means to generate a first steering torque, and a second steering torque. A second control algorithm for driving the biasing means in a decreasing direction, and the first control algorithm Operation amount determined by And the second control algorithm Operation amount determined by The Addition do it Driving the biasing means based on the obtained amount of addition operation In a vehicle steering system that is configured as described above, that is, the power steering actuator is also used as the actuator for lane tracking control, etc., the control algorithm for lane tracking and the control algorithm for power steering are combined and executed. As a result, the vehicle steering device can be made smaller and lighter, reliability can be improved, and the power steering can always operate to assist the steering force, and the power steering always operates. As a result, lane changes can be made with light steering force even during lane changes.
[0013]
Furthermore, it is possible to separate and describe and manage the control algorithm for lane tracking and the control algorithm as mere power steering, so that development can be facilitated.
[0014]
Furthermore, since power steering control and lane tracking control are completely separated and managed in time, the reliability of power steering control cultivated over many years can be maintained as it is, The reliability of the entire apparatus can be further increased.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
[0016]
In FIG. 1, a rectangle indicated by an outer imaginary line 10 is an outline of a vehicle on which the vehicle steering apparatus according to the present invention is mounted, and shows one side 12 of the steerable front wheel. As a steering mechanism for steering the front wheel 12, a steering device 14 of a rack and pinion type, a steering wheel 16 for operating the steering device 14, and a column 18 for coupling the steering wheel 16 and the steering device are shown. Yes.
[0017]
The column 18 has a torsion bar type steering torque sensor 20 that detects the steering force in the form of torque concentrically and converts it into an electric signal, and detects the rotation angle from the column via a belt to A potentiometer type steering angle sensor 22 that converts the signal into a signal is provided.
[0018]
On the other hand, an actuator 26 of a combination of an electric motor 24 and a ball screw that drive the rack up and down in the drawing in response to a command from a CPU described later is provided on the rack. As this steering torque sensor, a sensor that measures the torsional displacement of a torsion bar with a potentiometer and outputs it in analog is generally used for public use.
[0019]
Also, a vehicle speed sensor 28 that detects the speed of vehicle travel and converts it into an electrical signal, a yaw rate sensor 30 that detects a rotational speed (yaw rate) around the vertical axis of the motion of the vehicle and converts it into an electrical signal, and a vehicle interior And a control unit 34 (shown as a CPU) comprising a CPU that accepts electrical signals from these sensors and determines the current value of the motor 24. It is done.
[0020]
FIG. 2 shows the configuration of the CPU (control unit) in detail. An image captured by the CCD camera 32 is first sent to the image processing unit 32a, where processing such as feature point extraction and Hough conversion is performed. The processing result is sent to the travelable area recognition unit 32b, where a travelable area is searched. The output is then sent to the target route setting unit 32c where the plan of the course that is about to be run is formulated. These processing results are input to the CPU 34.
[0021]
The steering angle sensor 22 is a potentiometer, and its output is converted into a digital quantity via the A / D converter 22a and then input to the CPU 34. The output of the steering torque sensor 20 is also converted into a digital quantity through the A / D converter 20a and input to the CPU 34.
[0022]
When these signals are input, the CPU 34 calculates motor torque according to the algorithm shown in FIGS. 3 and 4 and drives the motor 24. As is well known, a D / A converter 24a and a motor amplifier 24b for converting this weak signal into a current value are inserted in the path for output to the motor.
[0023]
The CPU is provided with a storage device ROM for storing various gains necessary for calculation and the like, and is configured to be able to read ROM information as necessary. Separately from a manual switch SAS (abbreviation of Steer Assist Switch) 36, which can select the lane following mode at the driver's will, and a follow indicator light 38 for notifying the driver that the lane following mode is operating. Prepared (not shown in FIG. 1).
[0024]
In the above configuration, as is well known in the case of power steering, the torque sensor senses the steering torque applied to the steering wheel, and a current is supplied to the motor so that the steering torque falls within a predetermined amount. Assist steering force.
[0025]
As will be described later, in the lane tracking control, as disclosed in the prior art, the steering angle is set to the target steering angle θd calculated by the CPU based on information from the CCD camera, the steering angle sensor, the vehicle speed sensor, and the yaw rate sensor. The motor is driven to match. Furthermore, even during the lane following control, if the driver inputs a steering torque larger than the output of the motor, the direction of the vehicle can be changed according to the driver's intention regardless of the CPU's decision. You can change or avoid obstacles.
[0026]
3 and 4 are flowcharts showing the operation of the steering apparatus.
[0027]
In the illustrated control, the power steering is always operated. That is, the power steering control is performed if the vehicle is in a predetermined driving state regardless of the presence or absence of the lane tracking control.
[0028]
In the following explanation, the program shown in the figure starts with STEP-41 as the engine starts, and then proceeds to STEP-42 to read the information of the various sensors described above.
[0029]
The following STEP-43 to STEP-46 are control algorithms for power steering, and a motor torque T1 is calculated as a power assist amount.
[0030]
Specifically, in STEP-43, it is determined whether or not the detected steering force τs exceeds the reference value τo. If it is determined that the detected steering force τs exceeds the value, the process proceeds to STEP-44 and the coefficient γ depends on the direction of the steering force. Is determined. For example, it is positive when the steering force applied to the steering wheel 16 is in the right direction and negative when it is in the left direction, thereby replacing +1 or −1 with the coefficient γ.
[0031]
Next, the routine proceeds to STEP-45, where the difference between the detected steering torque τs and the reference value τo is obtained, and an amount obtained by multiplying the difference by the gain Ko is set as a motor torque command value T1 (operation amount). At this time, if the calculated torque T1 is larger than the allowable torque Tmax of the motor, the command value is limited to the maximum value Tmax. By using the coefficient γ, the calculation formula can be simplified.
[0032]
On the other hand, when it is determined in STEP-43 that the detected steering force does not exceed the reference value τo, the torque that is the power assist amount is unnecessary, so the process proceeds to STEP-46 and the command value of the motor torque T1 is set to 0. .
[0033]
Next, the process proceeds to STEP-47, where it is determined whether the above-mentioned SAS switch 36 is turned on. When this switch is not turned on, the process proceeds to STEP-49, where it is determined whether or not this switch has been pressed until the present from the flag bit.
[0034]
If the flag bit is 1, the driver determines that the switch has been previously turned on, and if the flag bit is 0, the driver has not turned on before and only wants the power steering function to work. It is estimated that Accordingly, the process proceeds to STEP-50, and the final torque to be output to the motor amplifier is determined as either the torque command value T1 calculated in STEP-45 or STEP-46.
[0035]
On the other hand, when the SAS switch is determined to be ON in STEP-47, the process proceeds to STEP-48, the flag bit is set to 1, the indicator lamp is turned on, and the process proceeds to STEP-51. The same applies when the flag bit is determined to be 1 in STEP-49.
[0036]
The processing from STEP-51 to STEP-62 is based on the control algorithm disclosed in Japanese Patent Application Laid-Open No. 5-197423 and Japanese Patent Application No. 7-31070 previously proposed by the present applicant. A brief description is given below.
[0037]
First, in STEP-51, the inclination angle ΘW of the vehicle (referred to as vehicle W) on the coordinates is calculated, and the process proceeds to STEP-52 to calculate the current position of the vehicle W. This is performed by obtaining the XY coordinate components (XW, YW) of the origin o of the XY relative coordinates of the vehicle W.
[0038]
Next, proceed to STEP-53 and set the target point P. This expresses the target route M as a sequence of points in the xy relative coordinates, and the distance xp (= VT) moved by a predetermined prediction time T in the x-axis direction at the current vehicle speed V of the vehicle W as an x coordinate component. Set as a point on the target route M.
[0039]
Next, proceed to STEP-54 to calculate the target yaw rate γm.
[0040]
First, the target point reaching yaw rate γm, that is, the yaw rate of the vehicle W for causing the vehicle W to reach the target point P from the current position (origin o) is obtained from an appropriate expression. Subsequently, an angular deviation ΔθP between the vehicle W and the target route M at the target point P is obtained, a yaw rate correction amount ΔγP for eliminating the angular deviation ΔθP is obtained, and ΔγP obtained from the target yaw rate γP is multiplied by a correction coefficient Km. This is done by subtracting the product and correcting the target yaw rate γP.
[0041]
The correction coefficient Km is obtained by calculating the curvature ρ and the road width D of the travelable route A (same as the travelable region described above) in STEP-55 performed in parallel with the processing below STEP-51 in the illustrated flow chart. -56 Using fuzzy inference from the curvature ρ, road width D, and vehicle speed V.
[0042]
Next, proceed to STEP-60, calculate the rudder angle that produces the target yaw rate γm as the target rudder angle δm using an appropriate formula, and proceed to STEP-61 to change the displacement angle of the motor 24 so that the target rudder angle δm is reached. The target value θD is calculated, and the routine proceeds to STEP-62, where feedback control is performed so that the displacement of the motor 24 coincides with the target value θD.
[0043]
Next, proceed to STEP-63, add the motor torque command value T1 for power steering control obtained in STEP-45 or STEP-46 and the motor torque command value T2 for lane tracking control, and finally output to the amplifier Set the motor torque command value T to go to STEP-64 and output.
[0044]
At this time, the torque command values T1, T2 (operation amounts) may be evaluated and added to each other, but in this embodiment, the necessary torque T1 as the power steering is multiplied by a coefficient K2 smaller than one. Command values T1 and T2 were added. The reason is that during lane following driving, the motor torque command value for lane following is determined so that the steering force returns to the target course as the distance from the target course in the lane increases. This is because, if the command value is large, the motor torque for lane tracking decreases and easily deviates from the lane.
[0045]
Next, proceeding to STEP-65, it is determined whether or not the SWS switch 36 is off. If the result is affirmative, proceeding to STEP-66, setting the Flag bit to 0 and turning off the indicator light, then proceeding to STEP-67. At the same time, if it is denied in STEP-65, proceed immediately to STEP-67. At STEP-67, it is judged whether the ignition key has been turned off (specifically, the engine has been stopped). If the answer is affirmative, the program proceeds to STEP-68 to terminate the program. If the answer is negative, STEP-42 Return to and repeat the above process.
[0046]
In the above-described embodiment, the power steering can always operate to assist the steering force, and the power steering always operates, so that the lane change can be performed with a light steering force even at the lane change. it can.
[0047]
On the other hand, lane following control is also performed in parallel, and steering is automatically performed following the lane only by the driver performing a global steering input. Specifically, in the above embodiment, since the target rudder angle δm is determined so as to travel in the center of the lane, the image is displayed when the driver holds the steering wheel straight on a substantially straight road. The information output of the device gives the front wheels very little steering along the lane.
[0048]
In addition, an automatic correction is made for deviation from the lane. For example, even if a disturbance caused by crosswinds or road surface irregularities is applied to cause the vehicle to deviate from the course, it automatically returns to the original course. Therefore, the driver can do almost nothing against the above disturbance.
[0049]
Furthermore, in the above embodiment, since the motor (actuator) 24 is used for both power steering control and lane tracking control, the entire apparatus can be reduced in size and weight, and reliability can be improved. .
[0050]
Furthermore, in the above embodiment, the power steering control algorithm from STEP-42 to STEP-46 and the lane tracking control algorithm from STEP-51 to STEP-61 are configured independently, so both are managed separately. can do. Therefore, it is easy to develop and modify, and also makes mistakes (software description mistakes called bugs)
) Opportunities can be reduced and reliability can be improved.
[0051]
Next, a second embodiment of the present invention will be described.
[0052]
FIG. 5 is an overall view of an apparatus according to the second embodiment.
[0053]
In the figure, an imaginary line 110 indicates the outline of the vehicle on which the present apparatus is mounted. This vehicle includes a steering wheel 112, a steering device 114 for turning the steering wheel 112, and a steering wheel 116 for operating the steering device. The steering wheel 116 and the steering device are coupled via a column 118.
[0054]
On this column 118 is a steering torque sensor 120 that detects a steering torque, an electric motor 124 that receives a command from a CPU, which will be described later, and applies rotational torque to the column, and an encoder that detects the rotational angle of the motor. Sensor 122 is provided. The motor 124 is provided with a worm-type speed reducer (not shown) that constitutes the actuator 126 integrally therewith.
[0055]
Further, a worm-type steering angle correction device 132 is provided between the steering wheel 116 and the column 118 so as to be relatively rotatable. The electric motor 130 that drives the correction device and the correction angle are detected. A potentiometer type correction angle sensor 128 is provided. The details of the steering angle correction device 132 are described in Japanese Patent Application No. 7-310070 previously proposed by the present applicant.
[0056]
In addition, a vehicle speed sensor 134, a yaw rate sensor 136, and a CCD camera 138 are prepared, and a CPU (control unit) 140 that drives the two motors based on information from these sensors is provided.
[0057]
Here, referring to the actuator 126 of the second embodiment, an actuator using a worm gear as a speed reducer on such a column is mainly used for public and public use in power steering of a lightweight vehicle. In such a type of power steering, a torque sensor for detecting steering torque is provided near the worm gear and on the steering wheel side. In this embodiment, both the actuator and the torque sensor are shared (shared) for power steering control and lane tracking control.
[0058]
FIG. 6 shows the configuration of the CPU (control unit) 140 in detail. The difference from the first embodiment is that two motor drive systems are prepared, and a signal from the correction angle sensor 128 is input to the CPU 140 via the AD converter 128a. . Although not shown in FIG. 5, a SAS switch 135 and a follow-up indicator lamp 137 for displaying that the lane follow-up function is in operation are prepared as in the first embodiment.
[0059]
7 and 8 are flowcharts showing the operation of the apparatus according to the second embodiment.
[0060]
As described above, in this embodiment, the two functions of power steering and lane tracking are operated separately in time so that both can be managed more independently.
[0061]
As described below, STEP-161 determines whether or not the Flag bit is on. Similar to the first embodiment, this Flag is set to ON when the driver turns on the SAS switch. That is, in the second embodiment, it is first determined by referring to this Flag whether the driver has selected the following function or the power steering function. When the flag bit is on, the lane following function is exhibited, and when it is not, the power steering function is exhibited.
[0062]
If it is determined in STEP-162 that the Flag bit is on, the process proceeds to STEP-180 and the above-described lane tracking control is performed. If not, the process proceeds to STEP-162 to determine whether the SAS switch is on. If the result is affirmative, the program proceeds to STEP-163, turns on the Flag bit, lights up the indicator lamp, and proceeds to STEP-180 and thereafter.
[0063]
On the other hand, when the result is NO in STEP-162, the process proceeds to STEP-170, and power steering control is performed up to STEP-177. Unlike in the first embodiment, the power steering control in the second embodiment is a vehicle speed responsive type in which the degree of assist is changed according to the vehicle speed.
[0064]
Since this concept is also known and does not form the gist of the present invention, briefly described below, the gain K is determined in association with the vehicle speed V in STEP-171. Specifically, the gain K is obtained by multiplying the basic value K0 by a value obtained by subtracting the ratio of the vehicle speed V / the upper limit vehicle speed V1 detected from 1.0. When the detected vehicle speed is equal to or higher than the upper limit vehicle speed, the gain K0 is set to zero. Then, the motor torque T is obtained by the same algorithm as in the first embodiment, determined by STEP-176, and output to the amplifier 124b by STEP-177.
[0065]
On the other hand, when affirmative in STEP-161 or 162, the process moves to the right STEP-180 and the lane following control is performed. That is, the motor torque command value T1 necessary for the lane following control is calculated in STEP-181 to STEP-189 as in the first embodiment, and is output to the amplifier 124b in STEP-192, which will be described later.
[0066]
In the second embodiment, steering angle correction control is also performed. In other words, the target correction angle (motor angle) αd proportional to the input steering torque is calculated by multiplying the detected steering torque τs appropriately set in STEP-190 by a coefficient (gain) K, and the feedback control amount is set so as to be this αd. Steering angle correction device comprising motor 130 and the like provided inside steering wheel 116, calculating motor torque command value T2 in STEP-191 based on the calculation result, proceeding to STEP-192 and outputting to motor amplifier 130b 132 is driven to correct the rudder angle.
[0067]
This is because a motor displacement proportional to the input steering torque is given to give the motor mechanism a kind of spring function, in other words, a compliance function. The details are described in the application previously proposed by the present applicant, and are not directly related to the gist of the present invention.
[0068]
When power steering control is performed, the motor torque command value T2 is set to zero in STEP-176. This is because the steering angle correction device 132 provided in the steering wheel 116 of FIG. 5 is constituted by a worm gear. That is, because the worm gear has irreversibility, the steering wheel 116 and the column 118 can be brought into the fixed state by stopping the supply power.
[0069]
That is, in the case of functioning as a power steering, if there is a portion that performs a spring action inside the steering wheel, the rigidity is lowered and the steering stability is also lowered.
[0070]
In the second embodiment, as in the first embodiment, in addition to assisting the steering force necessary for power steering control and enabling lane tracking control, the motor (actuator) 124 Since the steering torque sensor 120 is used for both power steering control and lane follow-up control, the entire apparatus can be reduced in size and weight, and reliability can be improved.
[0071]
Further, in the lane following control to which the steering angle correction function is added as in the second embodiment, a steering torque sensor is required. This steering torque sensor can also be shared by the power steering torque sensor, and is simpler. It becomes.
[0072]
Furthermore, in the second embodiment, the power steering control and the lane tracking control are performed separately in time. In other words, since the two control concepts can be managed completely separately, for example, the power steering control characteristics (whether or not it is a vehicle speed responsive type) can be freely changed without changing the basic algorithm. It is possible to increase the reliability.
[0073]
As for the lane tracking function, the steering angle correction function (STEP-190, STEP-191) that was not in the first embodiment can be added or deleted without affecting the power steering control algorithm. Can be modified freely. Furthermore, although not described in the present application, the concept of preventing a collision with another vehicle traveling in an adjacent lane as described in another application by the present applicant is also applied to the control of power steering. It can be easily incorporated without affecting the algorithm.
[0074]
Since each control algorithm can be managed independently in this way, it is possible to effectively suppress the occurrence of bugs at the time of software description often seen during development. In addition, since the power steering control software accumulated over many years can be used as it is, development can be performed efficiently and the development period can be shortened.
[0075]
Next, a third embodiment of the apparatus according to the present invention will be described.
[0076]
FIG. 9 is an overall view of a CPU (control unit) 240 of the apparatus according to the third embodiment.
[0077]
A difference from the previous embodiment is that a navigation system 244 is added. The CPU 240 is configured to recognize the environment in which the vehicle is currently traveling, for example, whether it is a highway or the like, while referring to information from the navigation system 244. Except for the fact that the sign is in the 200s, the remainder is the same as in the previous embodiment.
[0078]
10 and 11 are flowcharts showing the operation of the apparatus according to the third embodiment.
[0079]
In the following, based on the information from the navigation system 244 described in STEP-252, it is determined whether or not the vehicle is currently driving on a highway. And turn off the indicator light and proceed to Flow-2. Flow-2 relates to power steering control.
[0080]
On the other hand, when it is determined in STEP-252 that the vehicle is traveling on the highway, the process proceeds to STEP-254, and it is determined whether or not the current vehicle speed V exceeds a predetermined vehicle speed V2 (for example, 50 km / h). When it is determined that the current vehicle speed V does not exceed the predetermined vehicle speed V2, the power steering control is performed after STEP-253, and when it is determined that the current vehicle speed V exceeds the predetermined vehicle speed V2. Advances to STEP-261, determines whether or not the Flag bit is on, and if affirmative, advances to Flow-1 to perform lane tracking control.
[0081]
As in the previous embodiment, this flag is set to ON when the driver turns on the SAS switch for lane following control (not shown). If NO in STEP-261, proceed to STEP-262 to determine whether the SAS switch is turned on.If YES, proceed to Flow-1 via STEP-263 and deny Proceed to Flow-2.
[0082]
The details of the lane tracking control and the power steering control of Flow-1 and 2 are the same as those in the second embodiment, and thus detailed illustration is omitted.
[0083]
Since the third embodiment is configured as described above, the lane following control can be performed when the vehicle speed V exceeds the predetermined vehicle speed V2 after entering the highway. When the driver turns on the SAS switch, the lane following control is possible. Control is executed.
[0084]
On the other hand, even if the lane following control is once executed, for example, if the vehicle speed decreases and becomes equal to or less than the predetermined vehicle speed V2, the normal power steering control is performed again. The same applies when descending from a highway to a general road.
[0085]
Also in the third embodiment, in addition to assisting the steering force required in power steering control and enabling lane follow-up control as in the previous embodiment, the motor (actuator) 224 and the steering torque are provided. Since the sensor 220 is used for both power steering control and lane tracking control, the entire apparatus can be reduced in size and weight, and the reliability can be improved. Furthermore, since the power steering control algorithm and the lane follow-up control algorithm are performed separately in time, the same effect as in the second embodiment can be obtained.
[0086]
In the first embodiment, STEP-6 Three The summation process is not limited to the summation of the torques of the two concepts of power steering and lane following as disclosed, but the collision prevention with other vehicles traveling in the adjacent lane that the applicant has applied for separately A separate steering force torque control algorithm may be prepared, and the torque calculated there may be added together.
[0087]
In that case, a control algorithm for collision prevention is similarly constructed independently, and only when a danger of collision occurs, a program describing the algorithm is passed. Such processing can be easily performed by those skilled in the art having ordinary knowledge by the disclosed technology.
[0088]
In the second embodiment, the steering wheel 116 and the column 118 are locked when functioning as a power steering. However, when a spur gear is used instead of the worm gear, the steering wheel and the column are locked. A clutch means or the like for mechanically engaging / disengaging between the two is provided, and it is sufficient to engage with the clutch during power steering control.
[0089]
In the second embodiment shown in FIG. 5, the steering device 114 is shown as a manual type. However, even if the steering device is a hydraulic power steering, the lane following is performed. The function of can be achieved. At that time, since there is power assist by hydraulic pressure, the capacity of the motor 124 is much smaller and lane tracking can be performed. In other words, according to the present invention, it can be said that the steering device is a manual type and the motor 124 on the column is used for power steering.
[0090]
In the third embodiment, the highway is merely an example, and if the navigation system will evolve in the future, and the road that has been developed before the lane following operation can be performed, the navigation side can distinguish and display the road. It becomes possible to apply without being stuck to the highway.
[0091]
In the third embodiment, the lane follow-up control condition is that the SAS switch is turned on. However, as described regarding the object of the invention, the determination step of STEP-262 is deleted and the expressway is entered. Thus, the lane tracking control may be executed immediately when the vehicle speed V exceeds the predetermined vehicle speed V2. The control algorithm shown in FIGS. 10 and 11 is only an example.
[0092]
In the present invention, as described above, the first means (CCD cameras 32, 138, 238) for detecting the lane condition of the road ahead and the second means (image processing unit) for detecting the movement state of the own vehicle. 32a, 138a, 238a, travelable area recognizing units 32b, 138b, 238b, target route setting units 32c, 138c, 238c) and the output of the first and second means to determine the positional relationship of the host vehicle with respect to the front road lane. Third means (CPUs 34, 140, 240) for calculating the steering amount δm required for maintaining, steering means (steering devices 14, 114) for operating the steering wheels of the vehicle, and the third means The urging means (actuator 26 (electric motor 24)) for generating the first steering torque T, T2 in the steering means in accordance with the output of the steering wheel 16 and 116 is applied. Steering force detection means (steering torque sensors 20, 120, 220) for detecting the steering torque τs of the second steering torque, and the second steering torque applied to the steering wheel according to the output of the steering force detection means. The urging means can be driven in the decreasing direction. Specifically, the urging means is configured to be the electric motor 24.
[0093]
Further, when the steering device is driven according to the output of the third means, the rudder is interposed between the steering wheel and the steering device and is relatively displaced according to the output of the steering force detecting means. An angle correction means (steering angle correction device 132) is provided.
[0094]
Further, switching means (SWS switch 36 (STEP-47, STEP-162, STEP-262, STEP-252, STEP-254) is prepared, and at least the urging means (actuator 26 ( The electric motor 24)) is configured so that the generation of the first torques T1 and T2 can be suppressed (STEP-47, STEP-162, STEP-262).
[0095]
Further, a first control algorithm (STEP-51 to STEP-61, STEP-180 to STEP-188, Flow-1) for causing the steering means (14, 114) to generate the first steering torque δm. And a second control algorithm (from STEP-43 to STEP) for driving the urging means in a direction to decrease the second steering torque τs applied to the steering wheel according to the output of the steering force detecting means. -46, STEP-171 to STEP-175,
Flow-2) and switching means (STEP-47, STEP-162, STEP-252, STEP-254, 262), and at least one of the first and second control algorithms is performed by the switching operation of the switching means. The urging means is configured to be driven.
[0096]
Further, when the second control algorithm is executed in combination with the first control algorithm, the weight K1 of the determined operation amount T2 is different from that when it is executed individually (STEP-62). )
[0097]
Further, the switching means is provided with a switch (SAS switches 36, 135, 235) operated by the driver, and is configured to be switched via the switch.
[0098]
Further, the switching means includes vehicle speed detection means (vehicle speed sensors 28, 134, 234), and means (STEP-254) for invalidating the input of the switching means when the detected vehicle speed does not exceed a predetermined value. Configured.
[0099]
Further, the switching means is provided with a traveling environment determining means (navigation system 244) for determining the traveling environment, and is configured to switch when it is determined that the predetermined environment is traveling (STEP-252).
[0100]
Further, the switching means includes vehicle speed detection means and is configured to switch when the detected vehicle speed exceeds a predetermined value (STEP-254).
[0101]
In the above-described embodiment, the CCD camera is used to obtain forward lane information. However, the present invention is not limited to this, and the present invention can be applied to other methods. For example, in recent years, attempts have been made to embed magnetized landmarks on the road side and drive in the lane by relying on this magnetism. If this technique and more precise navigation information are put into practical use, CCD cameras Such information can be used instead of information.
[0102]
【The invention's effect】
A control algorithm for lane tracking in a vehicle steering system in which power steering actuators are also used as lane tracking control actuators Operation amount determined by And control algorithm as simple power steering Operation amount determined by The Addition do it Actuator is driven based on the obtained addition operation amount As a result, the vehicle steering device can be made smaller and lighter, reliability can be improved, and the power steering can always operate to assist the steering force, and the power steering always operates. As a result, lane changes can be performed with light steering force even during lane changes. In addition, the control algorithm for lane tracking and the control algorithm for simple power steering can be described and managed separately, so that development can be facilitated.
[0103]
Furthermore, since power steering control and lane tracking control are completely separated and managed in time, the reliability of power steering control cultivated over many years can be maintained as it is, The reliability of the entire apparatus can be further increased.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an entire vehicle steering apparatus according to the present invention.
2 is a block diagram showing details of a configuration of a control unit (CPU) in the apparatus of FIG. 1;
FIG. 3 is a first half flow chart showing the first half of the flow chart showing the operation of the apparatus of FIG. 1;
FIG. 4 is a second half flow chart showing the second half of the flow chart showing the operation of the apparatus of FIG. 1;
FIG. 5 is a schematic view showing an entire apparatus according to a second embodiment of the present invention.
6 is a block diagram showing details of the configuration of a control unit (CPU) in the apparatus of FIG. 5. FIG.
FIG. 7 is a first half flow chart showing a first half of a flow chart showing the operation of the apparatus according to the second embodiment;
FIG. 8 is a second half flow chart showing the second half of the flow chart showing the operation of the apparatus according to the second embodiment;
FIG. 9 is a block diagram showing details of a configuration of a control unit (CPU) of an apparatus according to a third embodiment of the present invention.
FIG. 10 is a first half flow chart showing a first half of a flow chart showing an operation of the apparatus according to the third embodiment.
FIG. 11 is a second half flow chart showing the second half of the flow chart showing the operation of the apparatus according to the third embodiment;
[Explanation of symbols]
10,110 vehicles
14,114 Steering device
16,116 Steering wheel
18, 118 columns
20, 120, 220 Steering torque sensor
22, 122, 222 Steering angle sensor
24, 124, 224 Electric motor
26,126 Actuator
28,134,234 Vehicle speed sensor
32, 138, 238 CCD camera
34, 140, 240 CPU (control unit)
36,135,235 SAS switch
38, 137, 237 Follow indicator light
132 Steering angle correction device
130,230 Electric motor
128,228 correction angle sensor
244 Navigation system

Claims (9)

A first means for detecting a lane condition of a traveling front road; a second means for detecting a movement state of the own vehicle; and a position of the own vehicle with respect to the front road lane from outputs of the first and second means. A third means for calculating a steering amount necessary to maintain the relationship; a steering means for operating a steering wheel of the vehicle; and a first steering for the steering means in accordance with an output of the third means. And an urging means for generating torque and a steering force detecting means for detecting a second steering torque applied to the steering wheel, and applied to the steering wheel according to an output of the steering force detecting means. In the vehicle steering apparatus configured to drive the urging means in a direction to decrease the second steering torque, the vehicle steering apparatus is configured to cause the steering means to generate the first steering torque. First control And algorithm, the conjunction and a second control algorithm for driving the urging means in a direction to reduce the second steering torque, an operation amount and the second to be determined in the first control algorithm vehicle steering apparatus characterized by driving the biasing means on the basis of the addition operation amount obtained by adding the operation amount determined by the control algorithm.   2. The vehicle steering apparatus according to claim 1, wherein the biasing means is an electric motor.   3. The apparatus according to claim 1, further comprising a switching unit and configured to suppress at least the biasing unit from generating the first steering torque by switching operation of the switching unit. Vehicle steering system.   2. The apparatus according to claim 1, further comprising a switching unit, wherein at least one of the first and second control algorithms is executed to drive the biasing unit by a switching operation of the switching unit. Or the steering device for vehicles of Claim 2.   When the second control algorithm and the first control algorithm are combined and executed, an operation determined by the first control algorithm by multiplying an operation amount determined by the second control algorithm by a coefficient 3. The vehicle steering apparatus according to claim 1, wherein the vehicle steering apparatus is configured to be added to a quantity.   5. The vehicle steering apparatus according to claim 3, wherein the switching unit includes a switch operated by a driver, and the switch is switched via the switch. 6.   The vehicle steering apparatus according to claim 6, wherein the switching means includes vehicle speed detection means, and means for invalidating an input of the switching means when the detected vehicle speed does not exceed a predetermined value.   5. The vehicle steering apparatus according to claim 3, wherein the switching unit includes a traveling environment determination unit that determines a traveling environment, and switches when it is determined that the vehicle is traveling in a predetermined environment.   5. The vehicle steering apparatus according to claim 3, wherein the switching unit includes a vehicle speed detection unit and switches when the detected vehicle speed exceeds a predetermined value. 6.

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