JP6617582B2 - Vehicle steering control device - Google Patents

Description

  The present invention relates to a vehicle steering control device.

  Non-Patent Document 1 describes a method of generating a target route (target travel locus) used for vehicle steering control. In this method, a control point on the path that minimizes the objective function is calculated, and a curved path function is applied to the calculated control point to generate a target path.

2014 IEEE IntelligentVehicles Symposium (IV) Julius Ziegler, Philipp Bender, Thao Dang and ChristophStiller, “TrajectoryPlanning for BERTHA- a Local, Continuous Method”, June 8-11, 2014. Dearborn, Michigan, USA.

  Since the vehicle target detection device described in Non-Patent Document 1 does not consider the shape of the route on which the vehicle is actually traveling, the smoothness of the curvature of the target route may be impaired depending on the curve function.

  An object of this invention is to provide the vehicle steering control apparatus which can produce | generate a smooth target path | route.

  A vehicle steering control device according to the present invention is a vehicle steering control device that controls steering of a vehicle based on a target route of the vehicle, and is based on a detection result of an in-vehicle sensor, A road calculation unit to calculate, a setting unit for setting a plurality of control points in the road so as to be at equal intervals or predetermined intervals along the traveling direction of the vehicle, and a side of the plurality of control points set by the setting unit A lateral position adjustment unit that adjusts the position by optimizing an objective function that uses the offset amount with respect to the center line of the runway and the path shape as parameters, a plurality of control points that are adjusted by the lateral position adjustment unit, and a curve A route generation unit that generates a target route based on the function, and a steering control unit that controls steering of the vehicle based on the target route generated by the route generation unit.

  According to the present invention, it is possible to perform steering control by generating a smooth target route.

It is a block diagram explaining the structure of a vehicle provided with the vehicle steering control apparatus which concerns on embodiment. It is a figure explaining the curve production | generation method by a uniform cubic B-spline. It is an example of a driving | running | working possible area | region and a control point. It is a figure explaining resampling. It is a figure explaining adjustment of the horizontal position of a control point. It is a flowchart of the control processing of a vehicle steering control apparatus. It is a figure explaining a curvature when a curve function is applied to each of two arrangement patterns of discrete points. It is a graph which shows the relationship between a control point space | interval ratio and the number of control points.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted.

  FIG. 1 is a block diagram illustrating a configuration of a vehicle 2 including a vehicle steering control device 1 according to the embodiment. As shown in FIG. 1, the vehicle steering control device 1 is mounted on a vehicle 2 such as a passenger car. The vehicle steering control device 1 controls the steering of the vehicle 2 based on the target route of the vehicle 2 as described later. The target route is a curve (running locus) that is a control target of the vehicle steering control device 1.

  The vehicle 2 includes an in-vehicle sensor 4, an ECU (Electronic Control Unit) 5, and an actuator 6. The in-vehicle sensor 4, the ECU 5, and the actuator 6 are respectively connected to a network that communicates using a CAN (Controller Area Network) communication circuit, and can perform mutual communication.

  The in-vehicle sensor 4 includes an internal sensor and an external sensor. The internal sensor is a detection device that detects the traveling state of the vehicle 2. The internal sensor includes a speed sensor. The speed sensor is a detection device that detects the speed of the vehicle. The external sensor is a detection device that detects an external situation of the vehicle 2. The external situation of the vehicle 2 is an environment or situation within a predetermined range of the vehicle 2. The external situation of the vehicle 2 includes, for example, the position of the boundary line of the lane, the lane center position and road width, the shape of the road, and the situation of the object. The state of the object includes, for example, information for distinguishing between a fixed obstacle and a moving obstacle, the position of the obstacle with respect to the vehicle 2, the moving direction of the obstacle with respect to the vehicle 2, the relative speed of the obstacle with respect to the vehicle 2, and the like. The external sensor includes at least one of a camera, a radar, and a rider. The detection result of the external sensor includes information regarding the external situation of the vehicle 2. The in-vehicle sensor 4 outputs the detection result to the ECU 5.

  ECU5 produces | generates the curve used as a target path | route using the control point (vector) set to the driving | running | working lane, and a tertiary B spline. First, an outline of a curve generation method using uniform (uniform) cubic B-splines will be described. FIG. 2 is a diagram for explaining a curve generation method using a uniform cubic B-spline.

A uniform cubic B-spline is expressed using a control point Q and a curve parameter t (0 ≦ t ≦ 1). When the knot point (vector) is P (t) and the natural number i, the knot point P (t) is calculated using the following equations (1) to (5).

同様にノット点Ｐ_２も算出することができる。また、曲線パラメータｔに対する曲線上のノット点Ｐ（ｔ）＝（ｘ（ｔ），ｙ（ｔ））の曲率κ（ｔ）は次の式（７）で表現される。

First, the curve segment P ₁ P ₂ shown in FIG. 2 will be described. Curve segment P ₁ P ₂ is generated using control points Q _0, Q _1, Q _2, Q ₃ . Knot point _{P 1} is i = 1, knot point _{P 2} is i = 2, when the curve parameter t = 0, knot point _{P 1,} and the case of curve parameters t = 1, the knot point _{P 2.} The knot point P ₁ is expressed as the following Expression 6 using Expressions (1) to (5).

Similarly knot point P ₂ can also be calculated. The curvature κ (t) of the knot point P (t) = (x (t), y (t)) on the curve with respect to the curve parameter t is expressed by the following equation (7).

Curve segment P ₁ P ₂ is generated using equation (1). The curve segment P ₂ P ₃ is the knot point P ₂ when the curve parameter t = 0, the knot point P ₃ when the curve parameter t = 1, and the control points Q _1, Q _2, Q _3, Q ₄ Generated using. In this way, curve segments are sequentially generated using a plurality of control points.

  Next, specific functions of the ECU 5 will be described. The ECU 5 includes a running path calculation unit 10, a setting unit 11, a lateral position adjustment unit 12, a route generation unit 13, and a steering control unit 14 as functional units.

  The travel path calculation unit 10 calculates a travel path that is a travelable area ahead of the vehicle 2 based on the detection result of the in-vehicle sensor 4. The travel path is an area in front of the vehicle 2 set on the road on which the vehicle 2 travels, and is an area where the vehicle 2 can travel without interfering with an object. The traveling path calculation unit 10 calculates a plurality of routes of the vehicle 2 based on the position of the boundary line of the lane and the position of the object detected by the external sensor that is the in-vehicle sensor 4, and the vehicle 2 and the object for each route of the vehicle 2. Interference risk is calculated. The travel path calculation unit 10 calculates an area where the vehicle 2 does not interfere with an object in the lane as a travelable area by evaluating the interference risk. When the object is a moving obstacle, the traveling path calculation unit 10 detects the speed of the vehicle 2 detected by the internal sensor that is the in-vehicle sensor 4 and the moving obstacle detected by the external sensor that is the in-vehicle sensor 4. Further, using the relative speed, the routes of the vehicle 2 and the moving obstacle are calculated, and the risk of interference with the moving obstacle is evaluated to calculate the travelable area.

  FIG. 3 is an example of a travelable area and control points. As shown in (A) of FIG. 3, the travel path calculation unit 10 is based on the lane boundary lines L1 and L2 detected by the in-vehicle sensor 4 and the position of the object A1. The runway that is is calculated. The runway is an area defined by boundary lines L3 and L4 set inside the lane boundary lines L1 and L2. The boundary lines L3 and L4 are represented by lines passing through white circles in the drawing.

  The setting unit 11 sets a plurality of control points for generating a target route for the travel path of the vehicle 2. The control point is a point for applying a curve function such as a cubic B-spline. The setting unit 11 sets a plurality of control points in the runway so as to be equally spaced along the traveling direction of the vehicle 2. As shown in FIG. 3B, the setting unit 11 sets a plurality of control points Q at equal intervals along the center line of the runway.

  Further, the setting unit 11 sets a plurality of control points Q with reference to the target route (previous target route) calculated in the previous process in the process after the first time. When the vehicle 2 performs the steering control, the vehicle 2 calculates the forward distance by using the preview time (for example, 0.7 seconds) determined in consideration of the response speed, the communication delay, and the like, and the speed of the vehicle 2. Steering is controlled with reference to the target path of the forward distance. For this reason, ECU5 does not change about the path | route (control object path | route) from the vehicle 2 to a front distance among target paths. The setting unit 11 recognizes the control point Q used to generate the control target route with reference to the previous target route, and does not change the control target route by not changing the position of the control point Q. Realize. As a result, it is possible to realize not changing the control target route at a higher speed than other known methods.

The setting unit 11 is used not to use the control point Q used in the previous target route but to generate a control target route for a section farther than the control target route in the process after the first time. The control point Q is resampled starting from the farthest control point Q. FIG. 4 is a diagram for explaining resampling. As shown in FIG. 4A, the forward distance is the product of the preview time T _pre and the current speed V _c of the vehicle 2. SP1 is the previous target route. The setting unit 11 does not change the position of the control points Q _{1 to} Q ₆ (white circles in the figure) used for deriving the forward distance. Then, the setting unit 11 resamples the subsequent control points Q _{7 to} Q ₁₁ with the farthest control point Q ₆ used for generating the control target route as a starting point. Setting unit 11, a position integrated value of Euclidean distance from the control point Q ₆ along the center line of the runway became a predetermined value, sets the control point Q _7. Then, the setting unit 11, a position integrated value of the Euclidean distance of the control point Q ₇ along the center line of the runway as a starting point becomes a predetermined value, sets the control point Q _8. In this way, subsequent control points are sequentially resampled. FIG. 4B is an example of control points resampled in the first and subsequent processes.

ｎは点列番号、Offsetは走路の中心線からの距離（オフセット量）、Gyは横Ｇ（曲率と車両２の速度の二乗との積）、Gyは横ジャーク（曲率変化率と車両２の速度の二乗との積）、Distは曲線長、W_{offs_Linear}はOffset線形項に対する重み係数、W_{offs_Square}はOffset二乗項に対する重み係数、W_Gyは横Ｇに対する重み係数、W_Gyは横ジャークに対する重み係数である。横位置調整部１２は、式（８）が最小となるＪを公知の最適化手法により求め、最小となるＪの評価パラメータに基づいて制御点Ｑの横位置を調整する。オフセット量を評価パラメータに含めることで、実際の走路の中心線に近い曲線となる制御点の横位置を求めることできる。横Ｇ、横ジャーク及び曲線長は、経路形状に関する評価パラメータであり、経路形状に関する評価パラメータに含めることで、実際の走路の経路形状を考慮して制御点Ｑの横位置を調整することができる。 The lateral position adjusting unit 12 adjusts the lateral positions of the plurality of control points Q set by the setting unit 11 by optimizing an objective function using the offset amount and the path shape with respect to the center line of the lane as parameters. The lateral position is a position in a direction orthogonal to the lane (a direction orthogonal to the traveling direction of the vehicle 2). An example of the objective function is the following equation (8).

n is the point sequence number, Offset is the distance from the center line of the runway (offset amount), Gy is the lateral G (product of the curvature and the square of the speed of the vehicle 2), Gy is the lateral jerk (the curvature change rate and the vehicle 2 Product of the square of velocity), Dist is the curve length, W _{offs_Linear} is the weighting factor for the Offset linear term, W _{offs_Square} is the weighting factor for the Offset square term, W _Gy is the weighting factor for the lateral G, and W _Gy is the weighting factor for the lateral jerk It is. The lateral position adjustment unit 12 obtains J that minimizes Equation (8) by a known optimization method, and adjusts the lateral position of the control point Q based on the evaluation parameter of J that minimizes. By including the offset amount in the evaluation parameter, it is possible to obtain the lateral position of the control point that is a curve close to the actual center line of the runway. The lateral G, the lateral jerk, and the curve length are evaluation parameters related to the path shape, and by including them in the evaluation parameters related to the path shape, the lateral position of the control point Q can be adjusted in consideration of the actual path shape of the road. .

ｔは曲線パラメータ、κ（ｔ）は曲率、Ｖは車両２の速度、Distはノット点間のユークリッド距離、つまり曲線長である。平均値を用いることで、曲線をより滑らかとすることができる。 Details of the offset amount (Offset), the lateral G (Gy), the lateral jerk (Gy), and the curve length (Dist) will be described. FIG. 5 is a diagram for explaining the adjustment of the lateral position of the control point. As shown in FIG. 5, the offset amount (Offset) is the distance between the knot point P and the center line L5 of the runway. The curve length (Dist) is the Euclidean distance between the knot points. The speed used in the lateral G and the lateral jerk is the current speed of the vehicle 2. The curvature used in the lateral G is an average value of curvatures at five curve parameters t (curve parameters t = 0, 1/5, 2/5, 3/5, 4/5 in the figure). The curvature change rate used in the horizontal jerk is an average value of the curvature change rates at five curve parameters t (curve parameter t = 0, 1/5, 2/5, 3/5, 4/5 in the figure). . The curvature change rate u is expressed by the following equation (9).

t is a curve parameter, κ (t) is a curvature, V is a speed of the vehicle 2, and Dist is a Euclidean distance between knot points, that is, a curve length. The curve can be made smoother by using the average value.

  In FIG. 3B, the arrow extending from the control point Q in the lane width direction illustrates the adjustment in the horizontal direction. FIG. 3B illustrates that all the control points Q are adjusted because there is no previous target route, that is, the first control point setting process by the setting unit 11. In FIG. 4B, since the previous target route exists and the control point Q is not adjusted for the control target route, the horizontal adjustment is not performed for the control point Q close to the vehicle 2, and the subsequent control is not performed. It is shown that the adjustment is performed for the point Q.

  The route generation unit 13 generates a target route based on the plurality of control points Q adjusted by the lateral position adjustment unit 12 and the tertiary B spline. The route generation unit 13 generates a target route using the uniform cubic B-spline curve generation method described with reference to FIG. The target route includes parameters used by the steering control unit 14. Examples of parameters include coordinates, curvature, and yaw angle.

  The steering control unit 14 controls the steering of the vehicle 2 based on the target route generated by the route generation unit 13. The steering control unit 14 controls the actuator 6 of the vehicle 2 so as to trace the target route. The actuator 6 is a steering actuator and controls the steering torque of the vehicle 2.

  Next, the control process of the vehicle steering control device 1 will be described. FIG. 6 is a flowchart of the control process of the vehicle steering control device 1. The control process shown in FIG. 6 is started when an operation start signal of the vehicle steering control device 1 is acquired.

  As illustrated in FIG. 6, the travel path calculation unit 10 of the vehicle steering control device 1 calculates a travel path that is a travelable area in front of the vehicle 2 based on the detection result of the in-vehicle sensor 4 as the travel path calculation process (S 10). To do. Thereby, for example, the travelable region R1 shown in FIG. 3A is acquired.

  Next, the setting unit 11 of the vehicle steering control device 1 determines whether or not the previous target route exists as determination processing (S12). When the setting unit 11 determines that the previous target route does not exist, the setting unit 11 performs a control point setting process (S16). As the control point setting process (S16), the setting unit 11 sets a plurality of control points Q in the runway so as to be equally spaced along the traveling direction of the vehicle 2. As a result, the control point Q shown in FIG. 3B is set.

  When it is determined that the previous target route exists, the setting unit 11 performs a determination process (S14). First, the setting unit 11 calculates the forward distance using the preview time and the speed of the vehicle 2, and recognizes the control point Q of the control target route based on the calculated forward distance. And the setting part 11 determines as the control point which does not change the recognized control point Q as a determination process (S14). Subsequently, as the control point setting process (S16), the setting unit 11 sets control points other than the control points that are not changed in the running path so as to be equally spaced along the traveling direction of the vehicle 2. Thereby, the control point Q (control point for adjusting the horizontal direction) shown in FIG. 4B is set.

  Subsequently, as the adjustment process (S18), the lateral position adjustment unit 12 of the vehicle steering control device 1 sets the lateral positions of the plurality of control points Q set in the control point setting process (S16) to the purpose of the above-described Expression 8. Tune by optimizing the function.

  Subsequently, the route generation unit 13 of the vehicle steering control device 1 performs, as the route generation processing (S20), based on the plurality of control points Q adjusted in the adjustment processing (S18) and the tertiary B spline. Generate a route.

  Subsequently, the steering control unit 14 of the vehicle steering control device 1 controls the steering of the vehicle 2 based on the target route generated in the route generation processing (S20) as the steering control processing (S22). When the steering control process (S22) is finished, the vehicle steering control device 1 finishes the control process shown in FIG. When the control process is finished, if the signal for ending the operation of the vehicle steering control device 1 has not been acquired, the process is started again from the runway calculation process (S10). As described above, the control process shown in FIG. 6 is repeatedly executed until an operation end signal of the vehicle steering control device 1 is acquired.

ｎは点列番号、Offsetは旋回半径１０ｍの円からの距離、Gyは横Ｇ（曲率と車両２の速度の二乗との積）、Gyは横ジャーク（曲率変化率と車両２の速度の二乗との積）、W_offsはOffsetに対する重み係数、W_Gyは横Ｇに対する重み係数、W_Gyは横ジャークに対する重み係数である。 Here, in order to explain the effect of the vehicle steering control device 1 according to the present embodiment, a case where a curve function is applied by optimizing discrete points will be described. FIG. 7 is a diagram illustrating the curvature when a curve function is applied to each of two arrangement patterns of discrete points. The speed of the vehicle 2 was fixed, and a circle was generated at three adjacent points. And the reference point on the path | route which makes the objective function J shown by following formula (10) the minimum was calculated | required.

n is the point sequence number, Offset is the distance from the circle with a turning radius of 10 m, Gy is the lateral G (product of the curvature and the square of the speed of the vehicle 2), Gy is the lateral jerk (the curvature change rate and the square of the speed of the vehicle 2) W _offs is a weighting factor for Offset, W _Gy is a weighting factor for lateral G, and W _Gy is a weighting factor for lateral jerk.

  The obtained reference points are shown in FIG. FIG. 7A shows a pattern in which seven reference points with rhombus marks are arranged and a pattern in which seven reference points with white circle marks are arranged. FIG. 7B is a diagram showing the relationship between the curvature and the curve length when a path is generated based on the reference point with respect to the two arrangement patterns. The horizontal axis is the curve length, and the vertical axis is the curvature. The graph corresponding to the reference point indicated by the rhombus is a solid line graph, and the graph corresponding to the reference point indicated by a white circle is a dotted line graph. As shown in FIG. 7B, the smoothness of the curves is greatly different even though the objective function has the same minimum value. Thus, when a curve function is applied by optimizing discrete points, the smoothness of the curve may be impaired depending on the curve function.

  On the other hand, the vehicle steering control device 1 according to the present embodiment samples a plurality of control points Q in the running path at equal intervals in the running path extending direction (traveling direction), thereby reducing the curvature change. A route, that is, a smooth target route can be generated.

  Further, the vehicle steering control device 1 according to the present embodiment calculates the travel path of the vehicle 2 based on the detection result of the in-vehicle sensor 4, arranges the control points Q at equal intervals in the travel path, and the control point Q. By reflecting the information on the travel path in the parameter of the objective function for adjusting the lateral position of the vehicle, it is possible to generate a path in consideration of the path shape on which the vehicle 2 actually travels. Thereby, the target route along the intention of the driver of the vehicle 2 can be generated. Further, the vehicle 2 including the vehicle steering control device 1 according to the present embodiment does not need to prepare a target route for steering control before traveling.

  In addition, since the vehicle steering control device 1 according to the present embodiment separately performs the position adjustment of the control point Q in the traveling direction of the vehicle 2 and the optimization of the lateral position of the control point Q, all are performed collectively. Compared to, it can be performed at high speed. In addition, the vehicle steering control device 1 according to the present embodiment does not perform optimization using the objective function in the position adjustment of the control point Q in the traveling direction of the vehicle 2, but only in the adjustment of the lateral position of the control point. By performing the optimization, it is possible to easily generate a target route according to the intention of the driver of the vehicle 2.

  The present invention can be implemented in various forms based on the above-described embodiments and various modifications and improvements based on the knowledge of those skilled in the art. Moreover, it is also possible to comprise the modification of the following Example using the technical matter described in embodiment mentioned above. You may use combining the structure of each embodiment suitably.

(Modification of curve function)
In the embodiment described above, an example in which the curve function is a cubic B-spline has been described, but the present invention is not limited to this. The curve function may be a parametric curve such as a Bezier, a B-spline of a different order, a NURBS (Non Uniform Rational B-Spline), or a spline interpolation curve.

(Variation of vehicle configuration)
In the embodiment described above, the travel path calculation unit 10 may calculate the travelable area with reference to map information as well as sensor information. That is, the vehicle 2 may include a map database including map information. Moreover, the vehicle-mounted sensor 4 is not limited to the sensor mentioned above. The in-vehicle sensor 4 may include a yaw rate sensor in order to use the yaw angle in a modified example described later. Furthermore, in order to acquire a road type, weather, etc. in the modified example described later, a communication unit that communicates with an external server may be provided.

(Modification of setting unit 11)
In the above-described embodiment, the example in which the setting unit 11 samples at equal intervals in order to reduce the curvature change of the route has been described, but various modifications are possible. That is, the setting unit 11 can set a plurality of control points in the runway so as to have a predetermined interval. In order to reduce the curvature change of the route, it is necessary to make the ratio of the intervals between the four adjacent control points 1.0, that is, close to equal intervals. The control point interval ratio is a ratio of adjacent control point intervals. FIG. 8 is a graph showing the relationship between the control point interval ratio and the number of control points. FIG. 8A shows the content described in the embodiment, and is a case where the control point interval ratio is fixed at 1.0. FIG. 8B is a graph adjusted within an allowable range (for example, 0.95 to 1.05) in which the control point interval ratio can be regarded as an equal interval. FIG. 8B shows a result of adjustment so that the point at which the yaw angle change is maximum is selected as the control point among the two adjacent points on the center line of the runway.

  In the above-described embodiment, the setting unit 11 may perform resampling in consideration of the possibility of locally changing the route and reducing the calculation load. As in the embodiment described above, the ECU 5 does not change the route (control target route) from the vehicle 2 to the front distance in the target route. That is, the setting unit 11 recognizes the control point Q used to generate the control target route with reference to the previous target route, and does not change the position of the control point Q. For this reason, in order to ensure the local changeability of a path | route, it is necessary to shorten a control point space | interval. However, there is a tradeoff in that the calculation load increases when the control point interval is shortened and the number of control points is increased. For this reason, the setting part 11 changes a control point space | interval as needed for the local changeability of a path | route. As an example, the setting unit 11 sets the control point interval for the traveling direction according to the road type, the surrounding environment, the weather, and the like. As a specific example, the setting unit 11 makes the control point interval of the general road shorter than the control point interval of the expressway. Or the setting part 11 shortens the control point interval at the time of congestion rather than the control point interval at the time of quiet. Alternatively, the setting unit 11 shortens the control point interval during rainy weather than the control point interval during fine weather. Alternatively, the setting unit 11 may set the control point interval according to the distance from the vehicle 2. As an example, as illustrated in FIG. 8C, the setting unit 11 sets the control point ratio to 1.0, that is, an equal interval in a section close to the vehicle 2 (for example, a predetermined value or less), and in a section farther than that. An equal ratio interval (control point ratio of 1.05) may be obtained by slightly increasing the control point interval. When the control points are set in this way, it is possible to achieve both a small change in the curvature of the path and a reduction in calculation load.

(Modification of the lateral position adjustment unit 12)
In the embodiment described above, the lateral position adjustment unit 12 may change the weighting coefficient of the objective function according to the road type, the surrounding environment, the weather, controllability, and the like. For example, when the risk of interference with an object or lane departure is high, the lateral position adjustment unit 12 increases the weight of the offset term from the center line of the runway. As a specific example, the lateral position adjusting unit 12 increases the weight of the offset term of the expressway than the weight of the offset term of the general road. Alternatively, the lateral position adjustment unit 12 increases the weight of the offset term at the time of congestion than the weight of the offset term at the time of quiet. Alternatively, the lateral position adjustment unit 12 increases the weight of the offset term in fine weather than the weight of the offset term in rainy weather. Alternatively, the lateral position adjustment unit 12 increases the weight of the offset term when the controllability is poorer than the weight of the offset term when the controllability is good.

  The calculation cycle of the flowchart of FIG. 6 is calculated with a short cycle of, for example, 200 msec. For this reason, as described in the above-described embodiment, the speed used in the lateral G and the lateral jerk can be the current speed of the vehicle 2. The lateral position adjustment unit 12 may adjust the speed used in the lateral G and the lateral jerk by various methods. For example, the lateral position adjustment unit 12 sets a lower limit value of the speed used in the lateral G and the lateral jerk (for example, 30 km / h), and when the current speed of the vehicle 2 falls below the lower limit value, the lateral position adjustment unit No. 12 adopts the set lower limit speed as the speed used for the lateral G and the lateral jerk instead of the current speed of the vehicle 2. As the speed of the vehicle 2 decreases, the influence of the lateral G and the lateral jerk decreases. For this reason, the route tends to be along the center line of the runway, which may be different from the sense of the driver of the vehicle 2 that actually travels. The lateral position adjustment unit 12 can solve the above problems by setting the lower limit value, and can generate a route that is close to the sense of the driver of the vehicle 2 that actually travels.

  The lateral position adjustment unit 12 sets an upper limit value of the speed used in the lateral G and the lateral jerk (for example, 80 km / h), and when the current speed of the vehicle 2 exceeds the upper limit value, the lateral position adjustment unit No. 12 adopts the set upper limit speed as the speed used for the lateral G and the lateral jerk instead of the current speed of the vehicle 2. As the speed of the vehicle 2 increases, the influence of the lateral G and the lateral jerk increases. For this reason, the route tends to be separated from the center line of the runway, which may be different from the sense of the driver of the vehicle 2 that actually travels. The lateral position adjustment unit 12 can solve the above problems by setting an upper limit value, and can generate a route that is close to the feeling of the driver of the vehicle 2 that actually travels.

  In the above-described embodiment, the horizontal position adjustment unit 12 uses five curve parameters as evaluation points in order to obtain the curvature used in the horizontal G and the curvature change rate used in the horizontal jerk. There is no limitation and six points may be used. Further, the lateral position adjustment unit 12 may change the number of curve parameters to be evaluated according to the order of the B spline. For example, when the quaternary B-spline is used, the horizontal position adjustment unit 12 may set the number of curve parameters to be evaluated to 6 points. By changing the number of curve parameters to be evaluated according to the complexity of the curve, it is possible to reduce the computation load.

(Modification of steering control unit 14)
The steering control unit 14 may control the steering so as to trace the target route in consideration of the steering input of the driver as well as when the vehicle 2 is automatically steered.

(Modification of control point position optimization)
In the above-described embodiment, the vehicle steering control device 1 separately performs the position adjustment of the control point Q in the traveling direction of the vehicle 2 and the optimization of the lateral position of the control point Q. In the divided area, the position adjustment of the control point Q in the traveling direction of the vehicle 2 and the optimization of the lateral position of the control point Q may be sequentially performed. Moreover, although the vehicle steering control apparatus 1 demonstrated the example which arrange | positions the control point Q at equal intervals in the advancing direction of the vehicle 2 in embodiment mentioned above, position adjustment of the control point Q of the advancing direction of the vehicle 2 is carried out. You may implement by optimizing an objective function. In this case, by including the integrated value of the absolute difference value of the distance between adjacent control points in the objective function, a route that matches the driver's feeling can be generated.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle steering control apparatus, 2 ... Vehicle, 4 ... Vehicle-mounted sensor, 10 ... Runway calculation part, 11 ... Setting part, 12 ... Lateral position adjustment part, 13 ... Path | route production | generation part, 14 ... Steering control part.

Claims (2)

A vehicle steering control device for controlling the vehicles steering,
A road calculation unit that calculates a road that is a travelable area ahead of the vehicle based on the detection result of the in-vehicle sensor;
A setting unit that sets a plurality of control points in the runway so as to be equidistant or predetermined intervals along the traveling direction of the vehicle;
A lateral position adjusting unit that adjusts the lateral positions of the plurality of control points set by the setting unit by optimizing an objective function using the offset amount and the path shape with respect to the center line of the runway as parameters;
A path generation unit that generates a target path by fitting the plurality of control points adjusted by the lateral position adjustment unit to a curve function;
A steering control unit that controls steering of the vehicle based on the target route generated by the route generation unit;
A vehicle steering control device. The vehicle steering control device according to claim 1, wherein the curve function is a cubic B-spline.

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