JP4030535B2 - Vehicle steering assist device - Google Patents

Description

  The present invention detects steering reference lanes based on road driving information and steering means for operating steering wheels, sets a reference target route (band) in the reference lane, and sets the reference target route (band). And a control unit that applies a reference guidance force determined according to the magnitude and direction of the deviation of the vehicle from the steering means to realize the vehicle travel along the reference lane. The present invention relates to a vehicle steering assist device that allows a vehicle to travel along a lane.

The present applicant has previously proposed a technique based on the above concept to be disclosed in Patent Document 1, but this is exclusively for automatically driving a vehicle by a steering assist device. However, on real roads, pylons are lined up when the lanes are changed and when you have to avoid a few things that you do not want to step on the road, or when you are under construction on the shoulders of the road, There are many problems that cannot be solved by automatic driving, such as when driving must be done, and it is actually necessary for the driver to intervene in the steering assist device. Further, for example, Patent Document 2 discloses a concept of performing automatic driving along each of a plurality of lanes.
JP-A-5-197423 JP-A-6-255514

  When it is assumed that the driver intervenes, it is necessary to solve the inconsistency problem between the steering angle determined on the control unit side for automatic driving and the steering angle intended by humans. Because if a human inputs a steering angle different from that system when the steering assist system is active, in the prior art, the system regards the human steering as a disturbance, and the actuator is also used to realize the steering angle determined by the system. In order to do their best, the system will resist the human. Moreover, even if it does not resist, once a skirmish occurs between the system and a human being, if the system side suddenly stops the rebellion, there will be inconveniences such as excessive power steering and excessive steering. Furthermore, if the system not only stops rebellion but also encourages driving along a new lane, a force will be generated that drags towards the new lane after the system has rebelled. In this case, excessive steering becomes more prominent.

  For example, when a lane change is performed under the technique disclosed in Patent Document 1, a guidance force that pulls the vehicle back to the original lane is applied even after the lane change is completed. The size is considerably strong because of the distance from the original lane. This makes it difficult to drive along the new lane after changing lanes.

  Moreover, in what was disclosed by patent document 2, the bank made by the potential method is prepared for every lane, and when driving in a lane, a steering system acts so that a vehicle may be pulled back to the center of a lane when approaching a white line. It is configured. However, in the method disclosed in Patent Document 2, if the lane is changed without operating the blinker, it is necessary to climb up the bank once and get off the force. As a driver, after being repelled, the repulsive force suddenly changes to a pulling force, making it difficult to pass the target course. This is just a snowy road with a saddle, and it feels like moving to another saddle, and it is hard to say that you can drive at will.

  In actual vehicle driving, there is not enough time to allow such a conflict with the system. Of the conflicts between the above-mentioned humans and the system during automatic driving, the lane change is frequent and the speed is generally high, so there is not enough time, so the system and humans work together to make the lane change. An excellent man-machine interface that can be shared is absolutely necessary.

  For example, taking the example in Patent Document 2 above, in normal driving, driving along the lane can be performed more easily by the bank constructed by the potential method, but when the driver intends to change the lane, the driver's lane change If the height of the bank made by the potential method can be lowered or eliminated, the lane change will be as easy as before.

  The present invention has been made in view of such circumstances, and the purpose of the present invention is that the system is normally taking the initiative, and human beings are optimized to run along the current lane from the system. It is an object of the present invention to provide a vehicle steering assist device that has constructed an excellent man-machine interface that can receive steering angle information through a steering wheel and perform steering based on this information.

  In order to avoid misunderstanding, the following terms among the terms used in this specification are defined as follows.

  Reference lane: The lane in which the vehicle is currently traveling.

  Reference target route: A route that is the target of tracking in the lane that the vehicle is currently driving.

  Second lane: A lane scheduled to travel after a lane change.

  Second target route: A route that is a target to be followed after a lane change.

  Bridge route: A travel route that connects the reference target route and the second target route. When traveling along this route, the system does not substantially provide information related to steering.

  Route (band): Since the above three routes generally have a width, they are referred to as “bands”.

                However, since the width may be 0 (that is, a line), the band is enclosed in parentheses.

  Guiding force: Steering force information given to the driver from the system side. The source of this information is the rudder angle, but it is difficult to handle with the rudder angle, so the direction and degree of steering are converted into rudder force and provided via the steering wheel. From the driver's point of view, the system feels as if it is guiding the direction to be steered.

  Symbol sign: The sign of the gain (subsystem sensitivity) and the reference value is positive. Steering angle and steering force are viewed from the driver as positive in the clockwise direction and negative in the counterclockwise direction, and handle right and left steering in a unified manner.

In order to achieve the above-mentioned object, the invention according to claim 1 is characterized in that steering means coupled to the steering wheel and capable of transmitting torque from the steering handle, coupled to the steering handle, and the steering means. Based on the driving means to be operated and the forward road information, at least the reference lane currently being traveled is detected, a reference target route (band) is set in the reference lane, and the deviation of the vehicle from the reference target route (band) is set. And a control unit that controls the operation of the drive means to apply a reference guiding force determined according to the magnitude and direction of the position to the steering means to realize vehicle travel along the reference lane. In the steering assist device, the control unit sets a second target route (band) in the second lane that travels after the lane change, and the vehicle unit travels along the second lane. It means for setting in accordance with a second induction force to be applied to the deflecting means to the magnitude and direction of the vehicle in deviation from the second target course (belt), in accordance with the reference induction force with time when changing lanes And a means for sequentially weakening and sequentially increasing the second induction force with the passage of time after a lapse of a predetermined time from the lane change .

According to a second aspect of the present invention, there is provided steering means connected to the steering wheel and capable of transmitting torque from the steering handle, connected to the steering handle, driving means for operating the steering means, and a road ahead. Based on the information, at least the reference lane that is currently running is detected, a reference target route (band) is set in the reference lane, and the deviation and the direction of the own vehicle from the reference target route (band) are set. And a control unit for controlling the operation of the driving means to apply the reference guiding force determined in the above to the steering means and realize the vehicle traveling along the reference lane. , Means for setting a second target route (band) in the second lane that travels after the lane change, and second guidance given to the steering means to realize vehicle travel along the second lane Is set according to the magnitude and direction of the deviation of the host vehicle from the second target route (band), and the reference guidance force is gradually reduced as time elapses when the lane is changed, and the second guidance force And a means for sequentially increasing the value as time elapses .

The invention described in claim 3 is characterized in that, in addition to the configuration of the invention described in claim 1 or 2 , the control unit includes a determination unit for detecting a driver's intention to change lanes .

In addition to the invention described in claim 1 or 2, the control unit according to the present invention responds to the deviation of the host vehicle from the reference target route (band) when the control unit weakens the reference guidance force when the lane is changed. And is configured to change the reference induction force .

According to a fifth aspect of the invention, in addition to the configuration of the first or second aspect of the invention, the control unit responds to the deviation in a region where the deviation of the own vehicle from the reference target route exceeds the reference value. The reference guidance force is determined, and the reference value is increased in order to weaken the reference guidance force when the lane is changed .

The invention described in claim 6 is characterized in that, in addition to the configuration of the invention described in claim 3 , the judgment criterion of the determination means is a winker operation of a driver.

According to a seventh aspect of the invention, in addition to the configuration of the third aspect of the invention, the deviation of the host vehicle from the reference target route (band) is equal to or greater than a first predetermined value, or the reference target The determination criterion of the willingness detection means is that the state in which the deviation of the vehicle from the route (band) is equal to or greater than a first predetermined value continues for a predetermined time or longer.

In the invention described in claim 8, in addition to the configuration of the invention described in claim 3 above, the determination criterion of the determination means is that at least a part of the own vehicle exists in the second lane. It is characterized by.

The invention according to claim 9 is provided with a steering force detection means for detecting a steering force in addition to the configuration of the invention according to claim 3 , and the detection value of the steering force detection means is a predetermined value or more. Alternatively, the determination value of the intention detection means is that the detection value of the steering force detection means continues for a predetermined time or more and is a predetermined value or more.

A tenth aspect of the present invention includes, in addition to the configuration of the third aspect of the present invention, a steering speed detecting means for detecting a steering speed, and the detected value of the steering speed detecting means is not less than a predetermined value. It is used as a judgment standard of the above-mentioned willingness detection means.

According to an eleventh aspect of the present invention, in addition to the configuration of the third aspect of the present invention, a route maintaining steering angle calculating means for calculating a steering angle necessary for maintaining the relative positional relationship between the reference lane and the host vehicle; And a steering angle detection means for detecting the current steering angle, and a difference between outputs of the route maintenance steering angle calculation means and the steering angle detection means is a predetermined value or more, or the route maintenance steering angle calculation means and It is characterized in that a determination criterion of the intention detection means is that the difference in the output of the steering angle detection means continues for a predetermined time or more and is a predetermined value or more.

In addition to the configuration of the invention described in claim 3 , the invention described in claim 12 indicates that the deviation of the own vehicle from the reference target route (band) is increasing or not decreasing. It is used as a judgment standard of the above-mentioned willingness detection means.

According to the first aspect of the present invention, the vehicle can automatically travel along the reference lane, and the reference guidance force is gradually reduced in accordance with the passage of time when the lane is changed, and after a predetermined time has elapsed since the lane change. As the second guidance force increases sequentially over time, the steering force felt by the driver is continuously switched from the one that naturally maintains the original lane before and after the lane change to the one that maintains the second lane. Thus, a natural lane change can be promised, and the lane change by the driver's intervention can be easily performed.

According to the invention described in claim 2, the vehicle can automatically travel along the reference lane, and when the lane is changed, the reference induction force is gradually weakened with the passage of time and the second induction force is made to have elapsed over time. Accordingly, the lane change can be realized while making the driver feel the steering force by giving the system the flexibility so that the conflict between the system and humans is reduced.

According to invention of Claim 3, it can respond appropriately to a driver's will to change lanes.

According to the invention described in claim 4 or 5, it is possible to simplify the technique of weakening the reference induction force.

  According to the invention of any one of claims 6 to 12, the driver's lane change intention display can be detected reliably and easily.

  Hereinafter, embodiments of the present invention will be described based on examples of the present invention shown in the accompanying drawings.

  FIGS. 1 to 11 show a first embodiment of the present invention, FIG. 1 is an overall configuration diagram of a vehicle steering assist device, FIG. 2 is a control block diagram, and FIG. 3 is a flowchart showing a part of a control algorithm. FIG. 4 is a flowchart showing a part of the control algorithm, FIG. 5 is a flowchart showing the remainder of the control algorithm, FIG. 6 is a diagram for explaining processing by the control algorithm, and FIG. 7 is a diagram showing a change in gain over time. FIG. 8, FIG. 8 is a cross-sectional view of the road for supplementing the explanation of the operation at the time of lane change, FIG. 9 is a diagram showing the distribution of steering force at the normal time on the road of FIG. 5, and FIG. FIG. 11 is a diagram showing a change in the steering force on the second target route after the intention to change the lane is determined.

  First, in FIG. 1, this vehicle steering assist device operates a steering handle 1 that is rotated by a driver, a steering shaft 2 that is rotated according to the operation of the steering handle 1, and a front wheel 5 as a steering wheel. The steering means 3, the drive means 4 which operates this steering means 3, and CPU15 as a control unit which controls the drive means 4 are provided.

  The steering shaft 2 is formed by connecting the other end of a transmission shaft 2a, one end of which is connected to the steering handle 1, and one end of a transmission shaft 2c via a torsion bar 2b. It is connected to the steering means 3. The steering means 3 is configured in a rack-and-pinion type with a pinion 8 provided at the other end of the transmission shaft 2c and a rack 9 meshing with the pinion 8, and both ends of the rack 9 are tie rods. 10 are connected to the left and right front wheels 5 respectively. Thus, the rack 9 is driven up and down in FIG. 1 by the rotation of the pinion 8, and both front wheels 5 are turned around the rotation axis in accordance with the operation of the rack 9, whereby the desired steering can be obtained. .

  The drive means 4 is connected to one end of the transmission shaft 2c in the steering shaft 2, and a worm gear mechanism for boosting the output of the motor 11 and inputting the output of the motor 11 to the transmission shaft 2c of the steering shaft 2. The worm gear mechanism 12 includes a screw gear 13 connected to the output of the motor 11 and a worm gear 14 provided on the transmission shaft 2c.

  The operation of the motor 11 in the driving means 4 is controlled by the CPU 15. The CPU 15 includes a steering force sensor 16 as a steering force detection means that is on the steering shaft 2 and detects the steering force, and the motor 11. A steering angle sensor 17 as a steering angle detection means which is an encoder for detecting a rotation angle, a vehicle speed sensor 18 for electrically detecting the speed of the vehicle, a yaw rate sensor 19 for electrically detecting the rotation speed around the vertical axis of the vehicle, In addition, information obtained by the CCD camera 20 that captures the road condition ahead of the vehicle is input. In addition, a SAS (Steer Assist System) switch 21 that can be switched at the driver's seat to perform lane guidance control, an indicator light 22 that indicates that the lane guidance function is in operation, and a driver's lane change A blinker (direction indicator) 40 for confirming the intention is connected to the CPU 15.

  Here, referring to the driving means 4 as an example, the actuator provided with the worm gear mechanism 12 on the steering shaft 2 is mainly used for public and public use in power steering of lightweight vehicles. In this type of power steering, a steering force sensor 16 for detecting a steering force is provided near the worm gear mechanism 12 and on the steering handle 1 side. In this embodiment, the driving means 4 and the steering force sensor are provided. Both 16 are shared with the lane guidance control system. Thus, the principle of the steering force sensor 16 is that the torsion bar 2b is twisted by receiving the steering force is converted into a linear displacement in the axial direction by a mechanism such as a cam and converted into an electric signal by a potentiometer or the like. It is used for publicly known public use.

  In FIG. 2, the image captured by the CCD camera 20 is subjected to processing such as feature point extraction and Hough transform in the image processing unit 23, and a travelable area based on the image after image processing in the image processing unit 23. The recognizable unit 24 searches for a travelable area, and based on the result, the target route setting unit 25 formulates a plan of a course that is about to be traveled and is input to the CPU 15.

  The output of the steering angle sensor 17 in the form of an encoder is directly input to the CPU 15, and the output of the steering force sensor 16 is an analog signal, and thus is input to the CPU 15 via the A / D converter 26, and the vehicle speed sensor 18 and the yaw rate sensor 19. Are also directly input to the CPU 15.

  A digital signal corresponding to the operation amount calculation result of the motor 11 in the CPU 15 is converted into an analog signal by the D / A converter 27, and the weak analog signal is converted into a current value by the motor amplifier 28 and given to the motor 11. It is done.

  Note that the CPU 15 includes a storage device (ROM) 29 for storing various gains and constants necessary for calculation, and information in the ROM 29 is read as necessary.

  Thus, the CPU 15 operates the motor 11 to generate a steering force that follows the lane to guide the driver in accordance with an algorithm that will be described later, and the front wheel 5 is moved according to the driver's steering force applied to the steering handle 1. An appropriate amount is deflected from the guidance course, and the driver receives a reaction force corresponding to the deflection amount as road surface information.

  The configurations of FIGS. 1 and 2 illustrated here are basically the same in the second to seventh embodiments described later, and will be described each time there is a slight difference.

  FIGS. 3 to 5 show control algorithms set by the CPU 15. In the following embodiment, the case where all the startup cycles of this system are set to 5 milliseconds is described. The system is activated when a predetermined condition such as the engine running is satisfied, and information from various sensors is read in step S111 in FIG. In the next step S112, it is determined whether or not the flag Flag-SAS is “1”, that is, whether or not the conditions for exhibiting the lane guidance function are met and the vehicle is in operation. In step S114 (FIG. 5), the output torque to the motor 11 is determined to be “0”. That is, the motor 11 is normally steered by the driver without generating any torque.

  When it is confirmed in step S113 that the SAS switch 21 has been pressed, the process proceeds to step S115, the flag Flag-SAS indicating that the system is being activated is set to “1”, the indicator lamp 22 is turned on, and step S118. Proceed to If the flag Flag-SAS has already been set to “1” in the previous step S112, the process proceeds to step S116. In step S116, it is determined whether the SAS switch 21 has been turned off. Then, the flag Flag-SAS is set to “0”, the indicator lamp 22 is turned off, and the process proceeds to step S114. If it is confirmed in step S116 that the SAS switch 21 has not been turned off, the process proceeds to step S118.

In step S118, the sign of the symbol used in the following calculation formula is decided. That is, when the steering force τs is positive (clockwise), the constant E is set to “+1”, and when the steering force τs is negative (counterclockwise), the constant E is set to “−1”. Constant E changes sign by sign of the thus steering force, but instead by a constant E, the following flow constant denoted by the constant E as a subscript, for example the gain K _E and the like shall be in accordance with this arrangement.

  In step S119 to step S123 following step S118, the same processing as that described in detail in the previous application (Japanese Patent Laid-Open No. 5-197423) is executed, and a target point Pi for guiding the vehicle is set from now on. Then, a correction coefficient Kmi used later is obtained. The details are described in the above publication, and will be described briefly here.

That is, in the XY fixed coordinate system shown in FIG. 6, xy relative coordinates are set with the vehicle W as the origin, the longitudinal direction of the vehicle W as the x axis, and the vehicle width direction of the vehicle W as the y axis. 20, the target route M based on the image information by the image processing unit 23, the steerable region recognition unit 24, and the target route setting unit 25 is set on the xy relative coordinate system. In step S119, the inclination angle of the vehicle W is set. seeking theta _W, the current position of the X-Y fixed position on the coordinate system (X _W, Y _W) of the vehicle W in step S120 is calculated, and further sets a target point Pi on the target course in step S121 M.

  In parallel with the processing of steps S119 to S121, the interruption processing of steps S122 and S123 is performed. In step S122, the travelable route Ai of the vehicle is obtained from the image information and the curvature ρi of the travelable route Ai is obtained. The lane width Li is obtained. In step S123, a correction coefficient Kmi is obtained by fuzzy inference from the curvature ρi, the lane width Li, and the current vehicle speed V. In view of the fact that it is difficult to smoothly converge to the target route M depending on the curvature of the travel route, etc., the correction coefficient Kmi is obtained according to the state quantities such as the curvature ρi and the lane width Li. It is.

  Here, the subscript symbol i represents a numerical value for each lane when there are a plurality of lanes ahead. For example, i = 0 is set for a vehicle currently traveling, i = + 1 is assigned to a numerical value relating to the right lane, and i = -1 is assigned to a numerical value relating to the left lane. If the constant E defined above is used, the left and right can be handled uniformly by placing i = E in the numerical value related to the adjacent lane. When changing lanes, the so-called double lane change, which changes two lanes at once, is not treated here. Therefore, even if the road has four or more lanes, i is only “0” or “E”.

  After the processing of steps S121 and S123, the process proceeds to step S130 shown in FIG. 4. In this FIG. 4, the flow part surrounded by the alternate long and short dash line is the flow that characterizes the first embodiment. However, the portions surrounded by the alternate long and short dash line are different from each other.

In step S130, it is determined whether or not the flag Flag-L / C is “1”. If it is not “1”, the process proceeds to step S131. In step S131, it is determined whether or not the flag Flag-D is “1”. judge. If this is also denied, the process proceeds to step S132, and it is determined whether or not the deviation ΔLo from the current travel lane center exceeds 40% of the lane width L. If the deviation ΔLo is within 40% of the lane width L, it is assumed that the driver is not willing to change the lane, and the process proceeds to step S133, the first timer Ct is set to “0” and the step advances to S134, the gain K _O regarding vehicle lane (the reference lane) to a predetermined magnitude of the gain K, also the gain K _E on the neighboring lane (second lane) keep the 0.

Here, since the gain K _E has two constants E of “+1” and “−1”, there are also two K _E. However, only the gain K _E relating to the direction of the steering force τs is to be discussed. , and the in this example keep always "0" in the opposite direction gain K _E and the steering force .tau.s.

When it is determined in the previous step S132 that the deviation ΔLo exceeds 40% of the lane width L, the flag Flag-D for determining the intention to change the lane is set to “1” in step S135. In step S136, the second timer Dt is set to 200 (since the cycle time is 5 milliseconds, a determination time of 1 second is provided). In step S137, the gains K _O and K _E are set in the same manner as in step S134 described above, and the process proceeds to step S138. In this step S138, it is determined whether or not the second timer Dt has become “0”. However, since Dt = 200 is set in the above step S136, the determination result in step S138 is initially negative and the process returns to step S133. Will return. As will be described later, if the second timer Dt becomes “0” after 1 second, the driver's intention to change the lane has been confirmed, so the flag Flag-D is set to “0” in step S139. Then, the flag Flag-L / C is set to “1”, and then in step S140, the first timer Ct is set to “1000”. This number “1000” corresponds to 5 seconds for the same reason as the second timer Dt described above.

In step S141, the gain Ko, the K _E modified as follows according to the count value of the first timer Ct. That is, in the first 2 seconds (600 <count value ≦ 1000), Ko is set to a new value by making Ko smaller than the previous number by a minute amount δK each time the cycle is turned. The magnitude of δK is selected so that it is exactly “0” after 400 cycles. During this time, K _E is consistently “0”. The next second the first timer Ct in (400 <counted value ≦ 600) 2 two gains Ko, none of K _E keep a "0". The last two seconds in (0 <counted value ≦ 400), but the gain Ko is consistently "0", the gain K _E is applied updating large numbers only .delta.K 'on the amount of the previous every cycle . And this .delta.K 'is also selected in an amount such that K _E is exactly K when turned 400 cycles. In this example, but by chance a δK = δK '= K / 400 , generally in time and the gain Ko becomes "0" from the K, is when the gain K _E is different from the time at which the K from "0" It is assumed that the algorithm is set so that numbers different from δK and δK ′ can be selected.

7 are thus two gains Ko upon definition, a state of temporal changes in the K _E are expressly as an example when the lane change to the right. That is, as shown in FIG. 7 (a), after the second timer Dt has counted 200, the gain Ko starts to decrease in response to the start of counting by the first timer Ct. When it becomes “600”, that is, after 400 cycles, it becomes “0”. On the other hand, as shown in FIG. 7 (b), the gain K _E is, until the count value of the first timer Ct after the count value of the second timer Dt is set to "0" is "400", " 0 ", but will increase thereafter. As apparent from FIG. 7, two gains Ko, K _E is shown a increased continuously reduced, and dressed alternates protagonist each other. In this case, the gain K ₋₁ when changing to the left lane is fixed to “0”.

If the flag Flag-D is “1” in the previous step S131, the process proceeds to step S142, where it is verified again whether or not the deviation ΔLo exceeds 40% of the lane width L. This is because the lane change was attempted once, but the lane change may be canceled for some reason. If it is determined in step S142 that 40% has been interrupted, the flag Flag-D is set to “0” in step S143 even if the intention to change lanes is being confirmed, and the process proceeds to step S133. return of the timer Ct in step S134 in the "0" gain Ko, the K _E the initial settings. On the contrary, if the deviation ΔLo continues to exceed 40% of the lane width L as a result of the verification in step S142, the second timer Dt required for determination in step S144 is set to “1”. The process proceeds to step S138. As a result of decrementing the second timer Dt in step S144, Dt = 0 occurs at some time as described above.

  If the flag Flag-L / C is already “1” in the previous step S130, the process proceeds to step S145 to perform an operation of reducing the first timer Ct by “1”. Thus, the first timer Ct is decremented by 1 every cycle.

After the gain Ko, is K _E are all defined in this manner, the process proceeds to step S170 in FIG. The processing from step S170 to step S172 is described in detail in the previous application (Japanese Patent Laid-Open No. 5-197423). Hereinafter, in brief, in step S170, the target yaw rate γmi is calculated. In calculating the target yaw rate γmi, first, when the vehicle W travels along the virtual route Sp (see FIG. 6) until it reaches the target point Pi. First, a target point reaching yaw rate γpi is obtained, and an angular deviation Δθpi between the vehicle W and the target route Mi at the target point Pi when the target point Pi is reached at this yaw rate γpi is calculated, and the yaw rate of the yaw rate for eliminating the angular deviation Δθpi is calculated. A correction amount Δγpi is obtained, and the yaw rate γpi previously obtained with the correction amount Δγpi is corrected based on the following equation, and the corrected yaw rate is used as a target yaw rate γmi.

                            [gamma] mi = [gamma] pi-Kmi. [Delta] [gamma] pi In the above equation, the correction coefficient Kmi used is that obtained in step S123.

Subsequently, in step S171, the target rudder angle δmi of the front wheel 5 necessary for generating the target yaw rate γmi obtained in step S170 is obtained, and in step S172, the rudder angle of the front wheel 5 is made coincident with the target rudder angle δmi. The target value θdi of the deviation angle of the motor 11 is calculated based on the gear ratio of the steering means 3 and the drive means 4. In step S173, as offset angle of the motor 11 is realized, the difference between the current motor deviation angle θt and the target offset angle Shitadi, gain Ko previously determined, are multiplied by K _E Calculate as a command value for motor torque. Here, there are two calculation formulas. For continuous running along the currently running lane, it is appropriate to use the motor torque T _O calculated with Ko = K in the above formula. On the other hand, if the vehicle continuously travels along the target route in the adjacent lane, it means that it is appropriate to use the motor torque T _E calculated with K _E = K.

  In FIG. 5, step S173 is surrounded by a dotted line and displayed in the sixth embodiment to calculate motor torque for the same purpose as that in step S173. The motor torque calculation in the sixth embodiment is described below. This is to mean that the portion corresponds to the process, and has no meaning in the first embodiment.

The motor torque command values T _O and T _E obtained in step S173 are determined as the motor torque by the arithmetic addition in the next step S174, and the determined amount is output to the motor amplifier 28 in step S175. However, the gain Ko, K _E is as defined in the previous step S141, a point at least one is "0", i.e. the motor torque command value T _O, at least one of T _E is "0" It is necessary to note a certain point.

  After the output to the motor amplifier 28, it is determined in step S176 whether or not the first timer Ct has become “0”. If it has not become “0”, the process returns to the original and executes the same cycle. If it is “0”, the flag Flag-L / C is set to “0” in step S177, and then the lane is updated in step S178. In other words, the lane after the lane change is renewed and registered as a currently running lane. As a result, “0” is assigned to the new lane, and “E” is assigned to the adjacent lane. After performing this procedure, the process returns to the original flow, and the same is repeated thereafter.

  Next, the operation of the first embodiment will be described. Before that, the structure of the road that is running will be briefly described with reference to FIG. In FIG. 8, three lanes are shown, and it is assumed that the current vehicle is traveling in the center lane. A target route is set for each lane by the method disclosed in the previous application (Japanese Patent Laid-Open No. 5-197423). This target route is not limited to the technique disclosed in the above publication, but may be constructed by another method, or may be prepared on the road facility side in hardware. As an example of such a road equipment side, a magnetic field line buried in the ground is known. However, the description will be continued here assuming that it is set by the technique disclosed in the publication.

  On the road shown in FIG. 8, the steering force τs before the lane change is set as shown in FIG. That is, the steering force τs is “0” when traveling on the target route of the current driving lane, but when the vehicle deviates from the target route, the steering force τs returns the vehicle to the central target route according to the deviation. Work in any direction. The relationship between the steering force τs and the deviation from the route at this time becomes a complex curve depending on the geometry of the undercarriage of the vehicle (geometric configuration), but in the following, it will be simplified for the sake of clarity. Thus, it is approximated by a straight line as shown in FIG. Since the upper limit of the steering force τs is physically determined by the capacity of the motor 11, the steering force τs does not increase linearly as it is far from the target route, but does not increase beyond a predetermined value. Even when the motor 11 has a margin, the rate of increase in the steering force τs is reduced as the distance from the target route is reduced, as is filed by the present applicant (Japanese Patent Application No. 8-21322). It is also possible to change the lane. However, they are not mentioned here because they are not directly related to the present invention. In any case, the steering force τs is a reference induction force described below.

This reference induction force changes as shown in FIG. 10 according to the gain Ko defined in step S141 in the control algorithm of FIGS. 3 to 5, and after the second timer Dt has been counted, the first timer As the count value of Ct decreases (time elapses), the reference induction force continues to decrease sequentially, and eventually the reference induction force disappears. As a result of the disappearance of this guidance force, the driver can steer with the same feeling as a normal vehicle. In addition, since the guidance force increased by the steering of the lane change is reduced with the lapse of time while disappearing, a natural feeling can be regained.

  FIG. 11 shows that the guidance force increases again as the count value of the first timer Ct decreases (time elapses) when the vehicle moves to the right lane, for example. At this time, the origin of the vehicle is not in the original lane (reference lane) but is placed on the second target route of the second lane. Therefore, in this case, the direction of the steering force felt by the driver with time is toward the second target route. If the vehicle is on the second target route, the guidance force is “0”. The guidance force increases in proportion to the distance from the second target path. This is the second induction force.

  Thus, the steering force felt by the driver is continuously switched from the one that naturally maintains the original lane before and after the lane change to the one that maintains the second lane, and a natural lane change can be promised.

  Even if the lane change is canceled for some reason on the way, the system detects this and restores the standard guidance force suitable for traveling along the original lane, so the driver does not need troublesome operation, You can continue to follow the original lane.

  In the first embodiment, it has been described that the lane change is not canceled after the flag Flag-L / C once becomes “1”, but the lane even when the flag Flag-L / C is “1”. If it is desired to deal with the situation of change cancellation, the result of affirmation in step S130 is not abruptly advanced to step S145, but the same determination process as in step S142 is provided in the middle, and flag flag is flagged when the determination result is negative -L / C may be reconfigured to return to "0" and then proceed to step S143.

  FIGS. 12 and 13 show a second embodiment of the present invention, FIG. 12 is a flowchart showing the main part of the control algorithm, and FIG. 13 is an explanatory diagram of the state of movement of the steering force on the road of FIG. is there.

  In the control algorithm of the second embodiment, the portion shown in FIG. 4 (the portion surrounded by the one-dot chain line) in the control algorithm of the first embodiment described above is the portion surrounded by the one-dot chain line in FIG. It is configured by replacement, and the other is the same as the first embodiment.

In FIG. 12, it is determined whether or not the flag Flag-L / C is “1” in step S230. If it is not “1”, in step S231, the deviation ΔLo from the target route of the currently traveling lane is calculated. It is determined whether or not it exceeds 50% of the lane width L. Here, 50% of the lane width L corresponds to the case where the vehicle is actually traveling on the white line. Again, | .DELTA.Lo | when was ≦ 0.5 L is respectively set after setting the timer Ct to "0" in step S232, the gain Ko to K in step S232, also the gain K _E to "0" To do.

If it is determined in step S231 that it exceeds 50%, the process proceeds to step S234, the flag Flag-L / C is set to “1”, and then the timer Ct is set to “1000” (5 seconds) in step S235. Set. The step S236, defines the gain Ko, K _E between the timer Ct is decreased. I.e. amounts of newly Ko minus a small amount δK from the previous figures with respect to the gain Ko, update by adding a small amount δK to the previous numerical Conversely the new K _E with respect to the gain K _E. That is, the proceeding in parallel with the increase in loss and gain K _E of the gain Ko. Here, the minute amount δK is set so that the gain Ko becomes just “0” 5 seconds after the timer Ct expires, in other words, δK = 0.001K. 5 seconds after the K _E has a K in reverse.

If the flag Flag-L / C is “1” in the previous step S230, the process proceeds to step S237, and it is verified whether or not the current deviation ΔLo has cut an amount 40% smaller than the previous criterion. . This is a verification that a lane change suspension may have occurred. If it still exceeds 40%, the timer Ct is reduced by "1" in step S238. Thus, if the flag Flag-L / C is “1” and the deviation ΔLo does not fall below the second reference value (40%), the timer Ct continues to decrease toward “0”. If the deviation ΔLo has fallen below the second reference value 40% in step S237, the process proceeds to step S239, this time the timer Ct is increased by “1”, and the initial value “1000” initially set is increased. To increase. And verify whether reached the "1000" in step S240, for less than "1000" is the gain Ko, it is contrary to the previous step S236 the change in K _E. That is increased by δK gain Ko for each cycle, contrary to the gain K _E decreases the same amount. When the count value of the timer Ct reaches 1000, the process proceeds from step S240 to step S242. After setting the flag Flag-L / C to “0”, the process proceeds to step S114 (see FIG. 5) of the first embodiment. To set the motor torque command value to zero.

  Thus, the processing in steps S233, S236, and S241 is the same as the flow after step S170 in the first embodiment (see FIG. 5).

  The second embodiment is different from the first embodiment in that the first reference value (50%) and the second reference value (the second reference value) are used for the deviation ΔLo without using a timer to confirm the driver's intention to change lanes. 40%), it is determined that there is a willingness to change the lane when the first reference value is exceeded, and it is determined that the lane change is canceled when a second reference value smaller than this is interrupted. This is what I did. As a result, the time required for the determination can be saved, and the responsiveness of the system is improved as compared with the first embodiment.

The two gains Ko, has increased at the same rate simultaneously gain of the second induction force and reduce the gain of the reference induction force in changing the K _E. As a result, Speaking what happens while the sum τs of the calculated values To and T _E of the torque command value are the same inclination as shown in FIG. 13, parallel to the movement from the reference lane toward the second lane Will do. Since the guidance force is “0” at the point where each line indicating the steering force intersects the horizon, the point where the guidance force is almost “0” when viewed from the driver is changed from the reference target route to the second target route. I feel like moving towards. During the movement, the vehicle is also moving forward, so that the bridge route having a guidance force of almost “0” extends straight from the reference target route to the second target route in a straight line toward the second target route. Should be visible. Thus, when the vehicle deviates from the bridge route, the guidance force according to the distance from the bridge route works in a direction to return the vehicle to the bridge route side, so driving while feeling the steering force well. Thus, unlike the first embodiment, once the flag Flag-L / C is set to “1”, the lane can be changed to the second target route through this bridge route. The system can be made more flexible with less conflict.

  Furthermore, when the lane change is stopped, the first embodiment directly returns to the original reference guidance force in the first embodiment, but in the second embodiment, the bridge itself is the reference target so that it returns to the original reference guidance force with time. It will degenerate towards the route. Since the degeneration is given with time, the driving can be continued with a more natural feeling even in the case of such suspension.

  In the first and second embodiments, since the lane change is not determined until the deviation ΔLo from the reference target route becomes a considerable amount, the driver is likely to return to the reference lane side with a large guidance force during this time. A third embodiment for improving such inconvenience will be described with reference to FIG.

This third embodiment is also drawn so that the portion surrounded by the one-dot chain line in FIG. 14 is compatible with the portion surrounded by the one-dot chain line in FIG. 4 in the first embodiment. In this third embodiment, in order to use the difference between the deviation angle θdo of the motor 11 suitable for traveling along the reference target route and the current steering angle θt as means for confirming the driver's intention to change lanes. First, it is necessary to calculate the deviation angle θdo. Only one cycle immediately after the SAS switch 21 (see FIGS. 1 and 2) is pressed can be directly applied to the lane following flow without considering the lane change. It must be. Therefore, in step S324, it is determined whether or not the flag Flag-ini is “1”. If it is not “1” (if this time is the first first cycle), the process proceeds to step S325 to set the flag Flag-ini to “ after the 1 ", set the timer Ct" 0 "at step S332, the gain Ko of the reference induction force at step S333 to" K ", and set the second induction force gain K _E to" 0 " The process proceeds to step S170 (see FIG. 5) in the first embodiment. For the first time, the target deviation angle θdo of the motor suitable for traveling along the reference target route is calculated.

Since the flag Flag-ini is “1” in step S324 from the next time, it is determined whether or not the flag Flag-L / C is “1” in step S330. If the result is negative, the process proceeds to step S331. It is verified whether or not the difference between the deviation angle θdo of the motor suitable for traveling along the target route and the current steering angle θt is larger than the reference value θ1. Here, since the deviation angle θdo uses a numerical value calculated one cycle before, θdo becomes θdo (t−1) if written correctly, but is simply displayed as θdo in order to avoid complication. When this gap is large, the driver inputs a value different from the value determined by the system. Therefore, it is considered that there is a willingness to change lanes, and when the standard value is not met, it is considered that there is no willingness. In other words, when it is determined that there is no intention to change the lane, the routine proceeds to step S332, where the timer Ct is set to "0", and in step S333, the reference induction gain Ko is set to "K" and the second induction force gain _KE. Is set to “0”, and the process proceeds to step S170 (see FIG. 5).

  When it is determined in step S331 that there is an intention to change lanes, the process proceeds to step S334, and in order to increase the certainty of the intention, a timer Dt for determination is set to 100 (0.5 seconds) in step S335. That is, if the affirmative state of step S331 does not continue for at least 0.5 seconds, it is not determined that the lane change is really performed. This happens when the front wheels are taken off by unevenness on the road surface, and the difference between the motor deviation angle θdo and the current steering angle θt suitable for traveling along the reference target route is the reference value. This is because even if it becomes larger than θ1, the phenomenon is transient and the lane change is not performed. This 0.5 second is used for confirmation. For this purpose, the process proceeds to step S336, the flag Flag-D is set to “1”, and then the process proceeds to step S332 to give the same gain as the previous time. Since the flag Flag-D is “1” in the next cycle, the process proceeds from step S334 to step S337.

In step S337, the amount obtained by subtracting the amount of the timer Dt by “1” is replaced with the timer Dt. In the next step S338, it is verified whether the timer Dt has become “0”. Proceeding to step S332, the same gain as the previous time is selected, but when it becomes “0”, it is determined that the driver's will is confirmed, and the process proceeds to step S339, and the flag Flag-D is set to “0” and the flag Flag- L / C is set to “1”, and then a timer Ct for performing crosslinking in step S340 is set to “1000”. Thereafter, the process proceeds to step S341. At step S341, the gain Ko of the same reference induction force and the second embodiment is decreased by .delta.K, to work to increase the second induction force gain K _E only .delta.K simultaneously.

  After the flag Flag-L / C becomes “1” in this way, the process proceeds from step S330 to step S342, where the deviation angle θdo of the motor suitable for traveling along the reference target route is set. And whether the difference between the current steering angle θt and the current steering angle θt is larger than the second reference value θ2. Again, for the same reason, θdo (t-1) should be written simply as θdo. It is assumed that the second reference value θ2 is a numerical value smaller than the reference value θ1. That is, it is verified whether the driver is continuously steering toward the second target route or whether the driver is returning to the reference target route.

Still rudder in step S342 is when it is determined that what is cut toward the second target course, the process proceeds to step S343, the vehicle deviation [Delta] L _E from the second target course is a small amount sufficient 0.1L Verify whether the following is true: In other words, it is verified whether the lane change is completed. If the value is not yet sufficiently small, the timer Ct is decreased by “1” in step S344, and then the process returns to step S341 to further increase or decrease the gain. However, if it is determined in step S343 that the second target route is sufficiently close, the process proceeds to step S345, the flag Flag-L / C is set to “0”, and then the lane that is currently traveling is determined in step S346. Substitute “0” in place of “E” for recognition by replacing with the reference lane, and return to the beginning of the flow.

When it is determined in step S342 that the difference between the motor deviation angle θdo suitable for traveling along the reference target route and the current steering angle θt is smaller than the second reference value θ2, the lane change is performed. In step S347, the flag Flag-L / C is set to “0”, the timer Ct is set to “0” in step S348, and the basic induction gain K o is set to “0” in step S349. the K ", and set respectively the second induction force gain K _E to" 0 ", the flow proceeds to step S170 (see FIG. 5).

  In this third embodiment, when the current steering angle shows a deviation greater than or equal to the reference value with respect to the steering angle optimized to continuously travel along the reference target route, the lane is changed to the driver side. Therefore, the responsiveness of the system can be further improved as compared with the first and second embodiments. This is because the steering angle is the first trigger for changing the lane and corresponds to the differential term in terms of control. It is common knowledge in this technical field that if this differential term is used as a trigger, control with an advanced phase can be achieved. In the third embodiment, a confirmation period of 0.5 seconds is provided even after the deviation above the reference value occurs. However, this is not an essential condition, and this can be omitted if the responsiveness is to be further improved. Needless to say. If the reference value at that time is set a little large, there will be no practical problem.

  Further, the third embodiment is configured to use a deviation state between the steering angle optimized for continuously traveling along the reference target route and the current steering angle for detection of lane change cancellation. Therefore, the responsiveness of the system is improved for the same reason.

  In addition, since the completion of the lane change is determined by the vehicle position deviation from the second target route being a minute amount, the completion of the lane change can be reliably confirmed.

  In addition, when the lane change is completed, the driver is allowed to update the lane because the current lane is newly recognized as the basic lane regardless of whether the timer Ct is “0” or not. There is also an effect that you can enjoy the guidance force along the new lane at the same time.

  FIG. 15 shows a fourth embodiment of the present invention. In this fourth embodiment as well, the portion surrounded by the one-dot chain line in FIG. 15 is compatible with the portion surrounded by the one-dot chain line in FIG. 4 in the first embodiment. It is drawn in.

In the fourth embodiment, the steering angular velocity whose phase is further advanced than the steering angle is detected to further improve the responsiveness of the system. In FIG. 15, the steering angle θd is obtained in steps S424 and S425. In step S430, whether or not the flag Flag-L / C is “1” is verified. If the result is negative, the process proceeds to step S431, where the current steering angle θt and the previous steering angle θ (t -1) is obtained, and it is verified whether or not the difference is larger than a predetermined steering speed Δθ. Since this difference {θt−θ (t−1)} has the same effect as a kind of differentiation from the fact that the flow is started at every constant speed, this difference can be considered as speed. Since there are two types of steering, right and left, if they are compared with absolute values, they can be handled uniformly. When a negative result comes out at step S431, as in the third embodiment described above, the timer Ct to "0" the process proceeds to step S432, defines the gain Ko, K _E at step S433, the next process (FIG. The process proceeds to step S170).

  If an affirmative result is obtained in step S431, the flag Flag-L / C is set to “1” in step S434, the timer Ct is set to 1000 (5 seconds) in step S435, and the gain is decreased and increased in step S436. .

  If a positive result is obtained in step S430, the process proceeds to step S437, and the current steering angle is smaller than the steering angle optimized to continuously travel along the reference target route as in the third embodiment. Verify that it is larger than the reference value θ2. If the result of the verification is affirmative, the process proceeds to step S438, and this time, it is verified whether or not the vehicle position deviation ΔLo from the reference target route exceeds 90% of the lane width L. As a result of the verification, if not yet exceeded, the process proceeds to step S439, the timer Ct is decremented by "1", and the process returns to step S436.

  If it is determined in step S438 that the vehicle position deviation ΔLo has exceeded 90% of the lane width L, the vehicle recognizes that the lane change has been completed, and proceeds to step S443 to set the flag Flag-L / C to “0”. After that, in step S444, an operation for newly registering and updating the currently running lane as the reference lane is performed.

  When it is determined that the current steering angle is smaller than the reference value θ2 that is smaller than the steering angle optimized in the previous step S437, it is determined that the lane change has been stopped, and the process proceeds to step S440 and the flag Flag-L / C Is set to “0”, the timer Ct is set to “0” in step S441, and the gain is redefined in step S442.

  According to the fourth embodiment, since the intention to change the lane is confirmed based on the information of the advanced phase called the steering angular velocity, the responsiveness of the system is remarkably improved. The discrimination criterion used in step S438 indicates that the deviation from the reference target path may be used as alternative information for the deviation from the second target path of the third embodiment.

  FIG. 16 shows a fifth embodiment of the present invention. In this fifth embodiment as well, the portion surrounded by the one-dot chain line in FIG. 16 is compatible with the portion surrounded by the one-dot chain line in FIG. 4 in the first embodiment. It is drawn in.

  This fifth embodiment shows that the intention to change lanes can be confirmed by the steering force τs instead of the steering angular velocity, and it is determined in step S531 whether the steering force τs exceeds a predetermined τo. If the result is affirmed, it is considered that there is a willingness to change lanes. In this example, the result of step S531 does not immediately determine that the vehicle intends to change lanes, but the steering force exceeds the reference value continuously for a predetermined time (0.5 seconds) as in the third embodiment. When configured for the first time, will will be confirmed. The reason for this is that if the steering force reaches a considerable amount and continues for a significant amount, it is because the driver has a strong intention to change lanes. Of course, holding the judgment for this predetermined time is not an essential condition of the invention, and this process can be omitted if the responsiveness is to be improved, as in the third embodiment.

In order to confirm the completion of the lane change, in this fifth embodiment, the difference between the steering angle θd _E optimized to continue traveling along the second target route in step S543 and the current steering angle θt is very large. It is determined that the angle is smaller than the small angle reference value θ3. The reason for this can be easily understood from the description of the previous application (Japanese Patent Laid-Open No. 5-197423) by the present applicant.

  Regarding other processing procedures, steps S530, S532 to S542, and S544 to S549 are the same as steps S330, S332 to S342, and S344 to S349 of the third embodiment shown in FIG.

  According to the fifth embodiment, since the steering force τs that can be directly measured is used as a judgment criterion, the calculation processing time can be saved, and errors can be reduced. In addition, when changing lanes, it is not necessary to first obtain the steering angle θdo optimized to continuously travel along the reference lane, so processing steps corresponding to steps S324 and S325 required by the third embodiment are required. Is a simple algorithm.

  In addition, in the technique disclosed here, the value of the steering force reaches a considerable amount, and it is considered that the driver is willing to change the lane when it continues for a certain predetermined time. It is not necessary, and it is easy to understand that if the reference value of the steering force is large, it is not necessary to wait for a predetermined time, and it may be immediately determined that the vehicle intends to change lanes.

  Although the responsiveness of the system is considerably improved by the fourth and fifth embodiments described above, a technique for further improving the responsiveness and a technique by which the driver can easily change the lane are described in the following sixth embodiment. I will explain it.

FIGS. 17 to 20 show a first reference example of the present invention, FIG. 17 is a flowchart showing a control algorithm corresponding to FIG. 3, and FIG. 18 shows a part of the control algorithm corresponding to the control algorithm of FIG. FIG. 19 is a flowchart showing the remainder of the control algorithm corresponding to the control algorithm shown in FIG. 4, and FIG. 20 is a diagram showing changes in the induced force over time.

  First, in FIG. 17, steps S611 to S613 and S615 to S623 correspond to steps S111 to S113 and S115 to S123 shown in FIG. 3, but the process of defining a constant E in step S118 surrounded by a dotted line in FIG. In the step, the definition is changed for the reason described later, and the processing is also moved to the subsequent step (step S626 in FIG. 18).

  In FIG. 18 and FIG. 19, it is verified whether or not the flag Flag-ini is “1” in step S624, which is continued from steps S621 and 623 of FIG. Since the flag Flag-ini is not “1” at first, the process proceeds to step S625. In step S625, the flag Flag-ini is set to “1”, and the process proceeds to step S632 to define various gains. Step S170 (see FIG. 5) in one embodiment proceeds to the following steps, and the target deviation angle θdo of the motor suitable for traveling along the reference target route is calculated.

  Since the flag Flag-ini is “1” in the next cycle, the result of step S624 is affirmed and the process can proceed to step S626. Here, the target deviation angle θdo of the motor calculated in the previous cycle is used. That is, strictly speaking, the target deviation angle θdo in step S626 is θdo (t −1), but is simply displayed as θdo for the same reason as in the previous embodiment. This process defines a new constant E. That is, if the current motor deviation angle θt is larger than the target deviation angle θdo including the sign, E = + 1, and if it is smaller, E = −1. When E is “+1”, it indicates that the current motor deviation angle θt has a deviation in the clockwise direction with respect to the motor deviation angle θdo necessary for traveling along the reference target route. ing. This represents a state in which the vehicle is going to move to the right from the reference target route. On the other hand, when E is “−1”, it represents a state in which the vehicle is going to deviate to the left from the reference target route.

The reason why the definition of the constant E is made difficult in this way is that the bridge route for changing lanes has a width in this reference example , and basically no inductive force is generated in this bridge route zone. This is because the steering direction of the driver cannot be specified simply. For example, assuming a lane change to the right on a road that curves to the left, the lane change is possible even if the steering wheel is slightly steered to the left (in this case τs is minus), and the sign of τs Then the driver's lane change direction cannot be specified. The reason for moving the process of defining the constant E to this point is that E cannot be defined until the target deviation angle θdo of the motor is calculated.

In step S630 following step S626, whether or not the flag Flag-L / C is “1” is verified. If not “1”, the process proceeds to step S631 to verify whether or not the winker is operating. At this time, the direction of the blinker is also read. Winker also proceeds to step S632 when the non-operating state, the reference induction force related to the left and right gains _E Ko, the _-E Ko K in both also left and right gain oK _E for the second induction force, _E K _E are both zero The respective steps are set, and the process proceeds to step S170 (see FIG. 5) and subsequent steps in the first embodiment. Here, if these gains _E Ko, _-E Ko, oK _E , and _E K _E are briefly described, the gains up to the fifth embodiment are applied to each of the reference target path and the second target path. However, in this reference example , left and right are managed separately for each target route, and independent gains are applied. For example, gains ₊₁ Ko and _-1 Ko represent the right and left gains with respect to the reference target route, respectively, and the gain is ₊₁ Ko when turning right. Similarly manage gain oK _E gain also reference target course side with respect to the second target course, the same gain on the opposite side as _E K _E.

When the winker is operating in step S631, the process proceeds to step S633 to set the flag Flag-L / C to “1”, and in the next step S634, the coordinate movement amount δXo of the target point on the reference target route and the second target route. , ΔX _E are set to “0”.

  Since the flag Flag-L / C is now “1”, the result of step S630 is changed to affirmative from the next time, and the process proceeds from step S630 to step S635. In step S635, it is verified whether or not the blinker has been canceled. If it has been canceled, in step S636, it is further verified whether or not the deviation ΔLo of the vehicle from the current reference target route exceeds 20% of the lane width. To do. If exceeded, it is verified in step S637 whether the temporal change in the deviation is increasing, and if it is increasing, the process proceeds to step S638 to verify whether the flag Flag-Ro is “1”. Briefly describing the flag Flag-Ro, the flag Flag-Ro is set to “1” when the bridge route starts to degenerate from the reference target route side to the second target route side.

  At first, since the flag Flag-Ro is not “1”, the process proceeds from step S638 to step S639, and it is verified whether or not the previous deviation ΔLo exceeds 60% of the lane width L. If not, the process proceeds to step S649, and if it exceeds, the horizontal coordinate δXo of the target point on the reference target route is shifted to the side by 50% of the lane width L, and the direction is changed to E Match the direction of.

  Here, the reason why step S637 is provided will be further described. To describe how the turn signal is used while traveling on a highway, the turn signal is usually issued when the lane is changed, but there are many cases where the turn signal is canceled even during the lane change. This is because on a highway, a large route can be changed even if the steering angle is small, so the mechanism that is provided in the winker and automatically cancels the winker rarely operates, and in general, the cancellation is performed manually. is there. In other words, because the driver arbitrarily cancels at the time of judgment, some people may cancel while changing lanes. Therefore, by providing step S637, even in such a case, if the deviation ΔLo from the reference target route is still increasing by a significant amount δL, it is assumed that the intention to change lanes is still maintained. Can be continued.

  Returning to FIG. 18 again, in step S641 following step S640, the flag Flag-Ro is set to “1”, and then the process proceeds to step S649. Since Flag-Ro = 1 now, the result of step S638 is affirmed from the next time, and the process can proceed to step S642 of FIG.

  In step S642, an operation of further shifting the X coordinate shift amount δXo of the target point on the reference target path by a minute amount δL from the previous shift amount is performed. The direction of the shift is matched with the direction of E. Next, the process proceeds to step S643, where it is verified whether or not the accumulated amount of deviation of the target point as a result of the deviation exceeds 95% of the lane width, and if not, the process proceeds to step S649 with the deviation.

Furthermore, if in step S636 (FIG. 18) the deviation ΔLo of the own vehicle at the time of canceling the blinker is less than 20% of the lane width L, this is considered that the lane change has been canceled and the step of FIG. The process proceeds to S644. In this step S644, it is verified whether or not the flag Flag-R _E is “1”, but since it is the first time, Flag-R _E = 0. Briefly describing the flag Flag-R _E , Flag-R _E = 1 when the bridge route starts to degenerate from the second target route side to the reference target route side. Here, since Flag-R _E = 0, the process proceeds from step 644 to step S645 to set the flag Flag-R _E to “1”. In step S646, it sets the reference target course on the shift amount of the X coordinate of the target point on the second target course DerutaXo, both [delta] X _E to "0", the flow proceeds to step S649. Since the flag Flag-R _E is "1" from the next time, the result of step S644 is affirmative, the process proceeds from step S644 to step S647. In this step S647, an operation of shifting the X coordinate shift amount δX _E of the target point on the second target route to the side by δL from the previous amount is performed, and the direction is set to the direction opposite to the E direction. In the next step S648, it is verified whether or not the accumulation amount of the deviation amount as a result of the deviation in this way exceeds 95% of the lane width, and if not yet 95%, the process proceeds to step S649 as it is.

In step S649, the gain _E Ko in the E direction is set to “0” and the gain _−E Ko in the direction opposite to E is set to “K” for the left and right gains of the reference induction force. As for the left and right gains of the second induction force at the same time, the E direction of the gain _E K _E is "K", put "0" and E in the opposite direction of the gain _-E K _E. Next, the process proceeds to step S650, where an operation of adding the deviation δXo to the coordinate Xpo of the target point on the reference target path is performed, and thereafter, the process proceeds to step S170 (see FIG. 5) and subsequent steps in the first embodiment.

If the determination in step S648 is affirmative, the process proceeds to step S651 on the assumption that the return to the original lane has substantially ended after the lane change is stopped, and the second target route that has been moved so far Return the coordinates of the target point to the original second target route. At the same time, both Flag-R _E and Flag-L / C are set to “0”. Subsequently, the process proceeds to step S652, and the gains _E Ko and _-E Ko of the reference induction force are returned to "K" on both the left and right sides, and the gains _E K _E and _-E Ko of the second induction force are set to "0". Returning the coordinates of the target point on the second target route to the original second target route by the operation of step S652 does not cause any harm, and the vehicle is in line with the reference target route. Traveling can be continued.

Furthermore, when the determination in step S643 is affirmative, the lane change is substantially completed, and the process proceeds to step S653. The coordinates of the target point on the reference target route that has been moved so far are returned to the original reference target route, and the flag Both Flag-Ro and Flag-L / C are set to “0” and the process proceeds to step S654. In step S654, the gains _E Ko and _−E Ko of the reference induction force are set to “0” on both the left and right _sides , and the second induction force The gains _E K _E and _-E Ko are set to “K”. By this work, the reference guiding force disappears and the second guiding force is established on both the left and right sides.

By the way, in the first reference example , the motor torques To and _TE are calculated by the following calculation method instead of the process of step S173 in the control algorithm shown in FIG. 5 of the first embodiment.

That is, when the difference between the current deviation angle θt of the motor and the target deviation angle θdo optimized for traveling along the reference lane is multiplied by E, the calculation of the motor torque To use _E Ko gain, the calculation of the motor torque T _E to the use of gain oK _E. On the other hand, when the difference between the current deviation angle θt of the motor and the target deviation angle θdo optimized for traveling along the reference lane is multiplied by E, the motor torque To is calculated. _-E Ko is used for the gain of the motor, and the gain _E K _E is used for the calculation of the motor torque T _E. When this calculation formula is used, the two induction forces are defined as follows.

  When E = +1 (ie when changing lanes to the right): The right half of the standard guidance force disappears and only the left half is effective, while the second guidance force is effective in the right half and the left half disappears. .

  When E = -1 (ie, when changing lane to the left): The left half of the standard guidance force disappears and only the right half is valid, while the second guidance force is conversely valid for the left half and the right half disappears. To do.

As a result, a bridge route zone having a guidance force of “0” appears between the reference target route and the second target route, and the driver does not receive any guidance force from the system when traveling in this region. (Of course, depending on the steering angle, the road surface reaction force resulting from the alignment of the front wheels naturally occurs.)
By the way, the degeneration starts in response to the output of step S637 for confirming that the lane change has been substantially performed. The state of the degeneration is shown in FIG. FIG. 20 exemplifies degeneracy at the time of right steering. FIG. 20A shows the guidance force immediately before the turn signal is operated in association with the reference target route, and FIG. Shows the guidance force immediately after the turn signal is operated, and FIG. 20 (c) shows the guidance force after the deviation ΔLo from the reference target route of the own vehicle exceeds 60%. As clearly shown in FIG. 20B, immediately after the winker operation, the right half of the reference guiding force disappears, and instead, the right half of the second guiding force is established. From the point of view of the driver, the right half of the reference guidance force feels as if it has moved to the right instantly by the lane width L, and the steering force can be freely steered by the amount of the moved lane width. The area has expanded. As shown in FIG. 20 (c), when the deviation ΔLo of the own vehicle from the reference target route exceeds 60%, the vehicle position exceeds the white line, so the coordinates of the target point on the reference target route are By shifting to the right to half the lane width, the left half of the reference guidance force will first move to the right by 0.5L, then move to the right by δL every cycle, and finally the step The second inductive force that satisfies the condition of S643 and is completely left and right is established.

According to the first reference example as described above, the bridge route (band) is instantaneously widened from the reference target route and bridged to the second target route by the operation of the blinker 40. Since the winker operation is a driver's clear intention to change lanes, the responsiveness of the system is improved as compared with the techniques disclosed in the first to fifth embodiments, and the bridge construction is completed instantly. This has the advantage that the driver can easily change lanes without substantially experiencing steering force resistance.

  In addition, it is confirmed that the lane change has been substantially made when the deviation of the host vehicle from the reference target route exceeds 60% of the lane width, and in response to the lane change confirmation, the bridge route ( The band) is suddenly reduced by half the lane width, and thereafter, in step S642, it is reduced by a minute amount δL. As a result, the second guidance force that the driver should enjoy can be obtained in a short time. In other words, I want to quickly degenerate the bridge route width to the second lane, but if I degenerate the whole rough and quickly, the guiding force will increase at a faster speed than the driver's lane change, and it will be forced to the second target route However, if the entire system is slowly degenerated, the inductive force will not be recovered and the system will not be saved. However, by controlling as described above, even if it is degenerated quickly, it can be degenerated quickly when there is no harm, and it can be slowly degenerated in a range where harm is expected, and after the lane change without showing the above drawbacks Can promptly enjoy the guidance force for traveling along the second target route.

  Further, step S637 is provided for determining whether the turn signal is canceled as a result of canceling the lane change or whether the driver cancels the lane change even though the lane change is continuously executed. As a result, the system becomes more intelligent and the practical convenience is remarkably enhanced.

  Furthermore, when the lane change is canceled, the bridge route is degenerated over time from the second target route side to the reference target route side, and even if the lane change is canceled by this technology, the vehicle is used as a reference. The reference guiding force that travels along the target route gradually narrows and increases. The steps S648, S651, and S652 are configured such that the original reference guiding force is restored when the width of the bridging route substantially matches the original reference target route. As a result, the driver feels that the steering force, which was initially free, is gradually tightened to the desired target route, and can smoothly benefit from the reference guidance force again. In this case, the speed of degeneration is constant, but this is generally done in a state where the deviation from the vehicle position to the reference target route is not so large when the lane change is stopped. This is because there is no need to change the speed. Of course, the speed may be changed in two stages or in multiple stages.

In addition to the first reference example , the bridge path width can be degenerated early and then slowly, and the following second reference example is prepared to show that. is there.

21 and 22 show a second reference example of the present invention. FIG. 21 is a flowchart showing a part of the control algorithm corresponding to the control algorithm of FIG. 4, and FIG. 22 corresponds to the control algorithm of FIG. It is a flowchart which shows the remainder of the performed control algorithm.

By the way, most of the flowcharts shown in FIGS. 21 and 22 are the same as those of the first reference example shown in FIGS. 18 and 19, and step numbers are given only to different parts to simplify the explanation. 21 and FIG. 22, it should be understood that the steps without step numbers are the same as those in the first reference example .

In step S739 instead of step S639 of the first reference example , it is determined whether or not the deviation ΔLo between the vehicle position and the reference target route exceeds 95% of the lane width L, and the degeneration is performed only when it exceeds. I have to. That is, the degeneration timing is not limited to that of the first reference example, and the same effect can be obtained even if the degeneration is performed by detecting this when the lane change is substantially completed.

As for the method of degeneration, the method of the first reference example was to degenerate by a predetermined large amount first and then degenerate in small increments, but in the second reference example , the degeneration speed was expressed by an exponential curve. It has been proposed to do. That is, in step S740, first, 10% of the lane width L is degenerated, and then in step S742 of FIG. 22, the degeneration speed is performed by a predetermined ratio (represented by α in the disclosed technique) for each remaining bridge path width. Yes. By this operation, the width of the cross-linking route is reduced, but since the degeneration is always continued by the remaining width α, the width is finally eliminated. The speed gradually decreases as the cross-linking width decreases, and mathematically exhibits exponential characteristics. Here, an example is shown in which α can be set differently from the initial speed of 10%. However, if α is set to 0.1, degeneration is performed from the beginning with the same characteristic characteristic.

According to the second reference example , it is possible to freely set the timing for starting the degeneration even when the lane change is confirmed or when the completion of the lane change is confirmed. In addition, the timing of the confirmation can be freely set by replacing a predetermined reference value without being particular about the case.

The degeneracy of the speed setting became clear that can be freely set by the second reference example. The desired degeneration mode can be realized simply by changing the mathematical formula.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. Is possible.

For example, in the first to fifth embodiments and the first and second reference examples , a technique based on Japanese Patent Laid-Open No. 5-197423 filed by the present applicant is disclosed as a technique for realizing traveling along the lane. However, the present invention is not limited to this. For example, it is obvious that the vehicle may travel along the lane with the technique disclosed in Japanese Patent Laid-Open No. 6-255514 cited as the prior art. When the latter technique is used, in addition to the technique of reducing or eliminating the height of the bank constructed by the potential method when changing lanes, the technique of moving the bank to the other lane side can be easily performed from the technique disclosed herein. Is.

1 is an overall configuration diagram of a vehicle steering assist device according to a first embodiment. It is a control block diagram. It is a flowchart which shows a part of control algorithm of 1st Example. It is a flowchart which shows a part of control algorithm of 1st Example. It is a flowchart which shows the remainder of the control algorithm of 1st Example. It is a figure for demonstrating the process by a control algorithm. It is a figure which shows the time change of a gain. It is sectional drawing of the road for supplementing operation | movement description at the time of a lane change. It is a figure which shows distribution of the steering force at the normal time on the road of FIG. It is a figure which shows the change of the steering force on the reference | standard target path | route after the will of a lane change was discriminate | determined. It is a figure which shows the change of the steering force on the 2nd target path | route after the will of a lane change was discriminate | determined. It is a flowchart which shows the principal part of the control algorithm of 2nd Example. FIG. 6 is an explanatory diagram of the state of movement of the steering force on the road of FIG. 5. It is a flowchart which shows the principal part of the control algorithm of 3rd Example. It is a flowchart which shows the principal part of the control algorithm of 4th Example. It is a flowchart which shows the principal part of the control algorithm of 5th Example. It is a flowchart which shows the control algorithm corresponding to FIG. 3 of a 1st reference example . It is a flowchart which shows a part of control algorithm corresponding to FIG. 4 of a 1st reference example . It is a flowchart which shows the remainder of the control algorithm corresponding to FIG. 4 of a 1st reference example . It is a figure which shows the time change of induction force. It is a flowchart which shows a part of control algorithm corresponding to FIG. 4 of a 2nd reference example . It is a flowchart which shows the remainder of the control algorithm corresponding to FIG. 4 of a 2nd reference example .

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Steering handle 3 ... Steering means 4 ... Driving means 5 ... Front wheel 15 as steering wheel ... CPU as control unit
16 ... Steering force sensor as steering force detection means 17 ... Steering angle sensor as steering angle detection means

Claims (12)

Steering means (3) coupled to the steering wheel (5) and capable of transmitting torque from the steering handle (1) and coupled to the steering handle (1), and operating the steering means (3) Based on the driving means (4) and the forward road information, at least a reference lane currently being traveled is detected, a reference target route (band) is set in the reference lane, and the vehicle from the reference target route (band) The driving means (4) is controlled so as to realize vehicle travel along the reference lane by applying to the steering means (3) a reference guiding force determined according to the magnitude and direction of the displacement of In the vehicle steering assist device, the control unit (15) includes a means for setting a second target route (band) in the second lane that travels after the lane change, and the second lane. Vehicle travel along Means for setting the second guidance force to be applied to the steering means (3) to be realized according to the magnitude and direction of the deviation of the own vehicle from the second target route (band), and a reference when changing the lane A steering assist device for a vehicle, comprising: a means for sequentially weakening the guidance force with the passage of time, and a means for sequentially increasing the second guidance force with the passage of time after a lapse of a predetermined time from the lane change. . Steering means (3) coupled to the steering wheel (5) and capable of transmitting torque from the steering handle (1) and coupled to the steering handle (1), and operating the steering means (3) Based on the driving means (4) and the forward road information, at least a reference lane currently being traveled is detected, a reference target route (band) is set in the reference lane, and the vehicle from the reference target route (band) The driving means (4) is controlled so as to realize vehicle travel along the reference lane by applying to the steering means (3) a reference guiding force determined according to the magnitude and direction of the displacement of In the vehicle steering assist device, the control unit (15) includes a means for setting a second target route (band) in the second lane that travels after the lane change, and the second lane. Vehicle travel along Means for setting the second guidance force to be applied to the steering means (3) to be realized according to the magnitude and direction of the deviation of the own vehicle from the second target route (band), and a reference when changing the lane A steering assist device for a vehicle , comprising: means for sequentially weakening the guiding force with the passage of time and increasing the second guiding force with the passage of time . The vehicle steering assist device according to claim 1 or 2, wherein the control unit (15) is provided with a means for detecting a driver's intention to change lanes . The control unit (15) is configured to change the reference guidance force according to the deviation of the vehicle from the reference target route (band) when the reference guidance force is weakened when the lane is changed. 3. A steering assist device for a vehicle according to 1 or 2 . The control unit (15) determines the reference guidance force according to the deviation in the region where the deviation of the host vehicle from the reference target route (band) exceeds the reference value, and weakens the reference guidance force when the lane is changed. 3. The vehicle steering assist device according to claim 1 , wherein the vehicle steering assist device is configured to increase the reference value . The vehicle steering assist device according to claim 3, wherein the determination criterion of the determination means is a winker operation of a driver. The deviation of the own vehicle from the reference target route (band) is not less than a first predetermined value, or the deviation of the own vehicle from the reference target route (band) is not less than a first predetermined value. 4. The vehicle steering assist device according to claim 3 , wherein a determination criterion of the intention detection means is that the operation continues for a predetermined time or more. 4. The vehicle steering assist device according to claim 3 , wherein at least a part of the host vehicle is present in the second lane as a criterion for determination by the determination means. Steering force detection means (16) for detecting the steering force is provided, and the detection value of the steering force detection means (16) is equal to or greater than a predetermined value, or the detection value of the steering force detection means (16) is a predetermined time. 4. The vehicle steering assist device according to claim 3 , wherein the determination criterion of the determination means is that it is continuously greater than or equal to a predetermined value. 4. The vehicle according to claim 3 , further comprising a steering speed detecting means for detecting a steering speed, wherein the determination value of the determination means is that the detected value of the steering speed detecting means is a predetermined value or more. Steering support device. A route maintaining steering angle calculating means for calculating a steering angle required to maintain a relative positional relationship between the reference lane and the host vehicle, and a steering angle detecting means (17) for detecting a current steering angle. The difference between the outputs of the route maintenance steering angle calculation means and the steering angle detection means (17) is a predetermined value or more, or the difference between the outputs of the route maintenance steering angle calculation means and the steering angle detection means (17) is a predetermined time or more. 4. The steering assist device for a vehicle according to claim 3 , wherein the determination criterion of the determination means is that it is continuously a predetermined value or more. 4. The vehicle according to claim 3 , wherein whether the deviation of the own vehicle from the reference target route (band) is increasing or not decreasing is used as a determination criterion of the determination means. Steering support device.

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