DE102005014983A1 - Parking aid device in which a corrected set steering angle is determined at intervals based on the difference between actual and set vehicle trajectories - Google Patents

Abstract

Parking aid device has a control unit with which a deviation of the actual vehicle trajectory from the set trajectory is measured for at least one trajectory parameter. The control unit has a controller with which at least a corrected set steering angle is determined dependent on the difference of the actual trajectory from the set trajectory. An independent claim is made for a method for determining the trajectory of a motor vehicle being parked.

Description

The The invention relates to an apparatus and a method for supporting a Driver when parking a motor vehicle in a parking space or Parking bag, wherein at least one segment comprising at least one Reference point for a target lane of the motor vehicle in the parking space or Parking bag is calculated. This is under a parking space a parking lot parallel to the road and under a parking bag a parking space perpendicular to Roadway understood.

Such a device is for example from the DE 38 13 083 A1 known, wherein a control of a possible travel of the motor vehicle is calculated in a parking space or parking bag. In the process, circular arcs are calculated as the travel path. Driving and / or steering instructions are issued acoustically and / or visually. In order to obtain a minimum turning circle, the steering wheel must be turned in one direction at the beginning of the parking until it stops. When parking in a parking space, the driver is prompted at a calculated reference point to turn the steering wheel in the opposite direction. However, real turning radii of a vehicle deviate from ideal turning radii due to tire pressure, tire wear, lane adjustments and other vehicle characteristics. The calculated due to the ideal turning radius target lane therefore often leads to an unsatisfactory parking result.

It is therefore known, desired lanes in certain reference points of To redetermine and / or optimize the desired lane. This process can However, be time consuming, so that a started parking must be interrupted and / or there is a loss of ride comfort.

Of the Invention is based on the prior art, the technical problem to provide a method and a device by which a support the driver when parking in a parking space or parking bag is improved.

The solution of the problem results from the objects with the features of claims 1 and 12. Further advantageous embodiments of the invention will become apparent from the dependent claims.

For this will be Deviations of an actual lane from a desired lane when parking of a motor vehicle in a parking space or parking bag in at least detected a reference point and by a web controller at least a corrected target steering angle determined. By driving off the target lane with corrected Steering instructions is a successful parking operation despite deviations possible. It is both a support the driver over the entire parking process, as well as partial routes possible. The target lane can in advance for different parking situations are optimized. By the overlay a previously optimized target lane with a corrected Target steering angle is a quick adaptation to deviations from the optimized target path possible. Is despite corrected target lane by driving and / or steering intervention no successful parking process feasible, for example, due gross driving error at the beginning of the parking process and / or due strong deviations of the vehicle tolerances, so is a new target lane ascertainable, the roadway starting in the parking space or parking bag is optimized by the new boundary conditions.

In a preferred embodiment the orbit controller includes yaw control (ψ control), wherein a deviation of the yaw angle of the vehicle is determined and the corrected target steering angle depending on the deviation of the yaw angle and the yaw angle control parameter is determined. deviations of the actual Yaw angles of a desired yaw angle are so by target steering interventions balanced.

In a further preferred embodiment is the maximum value of the target steering angle limited. As a limitation, for example, the maximum steering angle conceivable. However, it is also conceivable, depending on a driving state and / or a proximity of the vehicle to a lane boundary lower limits to choose. Determination of a corrected target steering angle, which is the maximum Exceed target steering angle, can thereby lead to a rejection of the desired lane.

In a further preferred embodiment the web controller comprises a position control (Y-control), wherein a translatory Deviation of the vehicle position to the desired vehicle position determined is and the target yaw angle depending on the translational Deviation and the Y-control parameter is determined. The larger a translational Deviation from the target lane fails, the steeper it is to select a corrected desired yaw angle with which the vehicle should return to the uncorrected target lane.

In a further preferred embodiment, the maximum value of the desired yaw angle be is bounded. As a limitation, for example, a maximum angle of 90 ° to the road is conceivable. Depending on a vehicle type and / or a traffic situation, however, other limitations are conceivable.

In a further embodiment are the ψ-regulation and / or the Y-control designed as a PID controller, wherein the gain factor of the proportional component greater than zero is and gains of the differential and integral components are greater than or equal to zero. Due to the differential component is a fast response of the controller reached. The integral component can cause permanent deviations be corrected, that is, a stationary one guidance accuracy of the system become. The amplification factors are determined by experiments and / or optimization calculations to certain Vehicle types and / or driving conditions customizable.

Preferably become the gain factors dependent on of a vehicle condition. A possible vehicle condition is for example, the vehicle speed. The individual values are for example a table removed. Next to it is It is conceivable to set constant values for the reinforcement to choose.

In a further embodiment the desired lane is described in a reference coordinate system. The target lane is composed of different segments. The desired roadway starts in the position in which the vehicle was stopped. The stopping of the vehicle can be preceded by a parking space measurement. The desired roadway ends in the desired target position of the vehicle in the parking space. For example, the ideal track can turn into a parking space approached three straight segments, the through circular arcs and / or ellipses are connected tangentially to each other. Thereby is given a simple picture of the ideal driveway in a parking space. The ideal driveway in a parking bag can consist of two straight segments approached which are connected by a circular arc. The target position can in turn, in turn, of an existing curb and / or considering Other parameters such as safety distances to other vehicles depending. By defining a reference coordinate system is the target lane dependent on at least one parameter definable.

Around The target lane must travel exactly the steering or Lenkaktuator set the desired steering angle. In a first embodiment is by means of a steering angle interface of the target steering angle transmitted to the steering or the Lenkaktuator. In another embodiment is added to the steering of the vehicle an additional steering torque over a Transmitted torque interface, wherein by means of a steering controller calculates the additional steering torque so is that the target steering angle is set by the steering actuator. Of the Lenkaktuator is for example a steering, with an electromechanical Power steering or an electronic stability program is formed. From the algorithms stored in the steering then results in a Steering movement. It can be assisted by the steering intervention Driver and / or fully automatic parking. In addition, it is conceivable that corrected driving and / or steering instruction visually, acoustically and / or haptically to the driver.

In a further preferred embodiment is a sensor for determining the desired roadway and / or the deviation of Actual lane of the vehicle from the target lane as a distance sensor, as Radddrehimpulssensor, as an acceleration sensor, as an angle sensor and / or as a motion sensor. In particular, the Raddrehimpulssensoren are characterized by a very high accuracy in determining the actual lane. For a good support the parking process preferably the entire vehicle environment detected by suitable sensors. However, it is conceivable in individual cases that individual areas of the vehicle environment for determining the ideal Target lane and / or deviations thereof are sufficient.

In a further preferred embodiment is the calculation of the target roadway adaptive to vehicle tolerances and / or a driving behavior customizable. The actual lane when parking depends on of vehicle tolerances such as tire pressure or track adjustments, as well the driving behavior of the driver. Through an adaptation, the optimal track for parking in parking spaces or parking bags adapted to existing conditions.

The Invention will be described below with reference to a preferred embodiment explained in more detail. The Figures show:

1 a schematic representation of a device for assisting a parking operation,

2 a target lane for parking in a parking space,

3 an illustration of a determination of a desired yaw angle and

4 an illustration for a determination of a corrected target yaw angle.

1 schematically shows a control unit 1 to support a parking operation. The device 1 includes a computing unit 12 for determining a desired roadway, a computing unit 14 for determining an actual roadway and a regulation 16 to determine continuous driving and / or steering instructions based on the desired lane and the actual lane. The arithmetic unit 12 , the arithmetic unit 14 and the scheme 16 can be designed as a common component or separately. For the desired roadway and the actual roadway, the vehicle environment, the vehicle orientation and / or the vehicle movement by sensors 2 detected. The vehicle environment is for example the size of a parking space, the distance to a curb or the distance to an obstacle. The desired roadway is determined by the determined vehicle environment and the current vehicle position. Deviations from a desired roadway, for example, due to predictions about the vehicle environment in comparison with a detected vehicle environment recognizable. Based on the target lane and the actual lane are by the scheme 16 determined continuous driving and / or steering instructions, so that the predetermined target lane is followed as accurately as possible. The steering instructions are provided to the driver by an optical and / or acoustic display unit 3 communicated. The driver is assisted by the visual and / or acoustic signals in the parking process.

Additionally and / or alternatively, the steering instructions are sent to a control device 4 so that a correction of a steering intervention based on by the regulation 16 Determined steering instructions (target steering angle or additional steering torque) takes place.

Instead of a correction of the steering intervention by the control device 4 is also a change of a restoring torque conceivable, which is perceived on the steering wheel by the driver. The driver is thus haptically pointed to a necessary correction of the steering intervention. However, the steering intervention is at the discretion of the driver.

For one Fully automatic parking operation are in addition to a steering intervention also interventions in the longitudinal dynamics the vehicle conceivable.

2 schematically shows an ideal infrastructure 5 for parking a vehicle 6 in a parking space 7 , The ideal track 5 consists of three straight segments 51 . 52 . 53 together, through circular arcs 54 . 55 are connected. The individual segments 51 - 55 are constantly merging.

By the reference coordinate system x, y, the desired path 5 as function y _lane = f (x _lane ). Is thus to each x position x _path of the vehicle 6 a uniquely assigned y-nominal position y _web defined. Instead of parameterizing with the x position, parameterization with the y position is also conceivable.

In addition, for each position x _path , y _path an associated desired yaw angle ψ _BAHN = f (x _path ) can be defined.

3 illustrates the determination of the desired yaw angle ψ _path by numerical differentiation with the Weginkrementen Δx _{path, ψ} . The desired yaw angle ψ _path can thus be determined as: ψ train (x train ) = arctane ((y train (x train ) - y train (x train - Δx Railway ψ, )) / Ax Railway ψ, )

The associated desired steering angle δ _trajectory = f (x _trajectory ) can also be determined by numerical differentiation: δ train (x train ) = L / Δx Railway δ, * Cos (ψ train (x train )) * Sin (ψ train (x train ) - ψ train (x train - Δx Railway δ, )) With: ψ train (x train ) = arctane ((y train (x train ) - y train (x train - Δx Railway ψ, )) / Ax Railway ψ, ) ψ train (x train - Δx Railway δ, ) = arctane ((y train (x train - Δx Railway δ, ) - y train (x train - Δx Railway ψ, - Δx Railway δ, )) / Ax Railway ψ, ) and the path increment Δx lane _{, δ} , and the vehicle wheel base L (center of the front to center of the rear axle).

By choosing the path increments Δx _{path, ψ} , Δx _{path, δ it} can be determined how far into the "future" is looked, ie, how exactly the differentiation is to be carried out By suitable choice of the parameters, dead times and system response times can be used in the track control offset. Preferably, equal time steps for Ax _{path, ψ,} Ax _{web δ} selected. It is also conceivable for the path increments Ax _{path, ψ,} Ax _{web δ} parameterized function of specific properties of the vehicle and / or driving conditions.

In order to be able to better correct deviations of the actual lane from the desired lane, a path control is used according to the invention which calculates a corrected desired steering angle δ _SOLL as a manipulated variable as a function of a corrected desired yaw angle ψ _SOLL . 4 illustrates the relationships.

The translational deviation can be by describing the parameterized form as Δy = y train (x train ) - y FTA

The greater the translational deviation in the y-direction from the desired roadway, the steeper the yaw angle is selected, with which the vehicle is to be returned to the desired roadway. For this purpose, with the translatory deviation in the y direction and a desired yaw angle ψ _path, a corrected setpoint yaw angle ψ _{SOLL is} determined by means of a Y controller designed as a PID controller: ψ SHOULD = Δy · PID Y + ψ train (x train )

The maximum value of the corrected target yaw angle ψ _SOLL is preferably limited. For example, for certain vehicle types, an angle of 90 ° in the direction of the desired roadway could make maximum sense.

The gains of the Y controller can be constant or dependent from a vehicle state, for example, the speed determined become. dependent gains are stored in a table and this can be removed during the parking process. The amplification factors of the I and D component of the Y controller can Be zero, so a pure P-controller is used for the correction becomes.

If the deviation Δy = 0, then the following applies: ψ _SOLL = ψ _web (x _web ), which corresponds to a pure feedforward control.

The ψ deviation Δψ from the desired trajectory at a specific position x _{trajectory of} the vehicle can be determined as follows: Δψ = ψ SHOULD - ψ train

On the basis of this deviation of the yaw angle and the desired steering angle δ _path (x _path ), a corrected nominal steering angle δ _{SOLL of} the vehicle is calculated by a als controller designed as a PID controller: δ SHOULD = Δψ · PID ψ + δ train (x train )

The maximum value of δ _SOLL is preferably limited. For example, the physically greatest possible steering angle of the vehicle can be most sensible.

The gains of the ψ controller can be constant be or also dependent determined by the vehicle condition and a corresponding table whereby the amplification factors of the I and D Share of the ψ controller can Be zero, so a pure P-controller is used for the correction becomes.

If the deviation of the yaw angle Δψ = 0 then δ _SOLL = δ _path (x _path ), ie. there is a pure feedforward control.

Claims (22)

Device for assisting a driver when parking a motor vehicle in a parking space or parking bag, comprising at least one sensor and at least one control unit, wherein at least one segment comprising at least one reference point for a target road of the motor vehicle can be calculated into the parking space or parking bag, characterized that by means of the control unit ( 1 ) at least in the one reference point a deviation (Δx, Δy, Δψ) of an actual roadway (x _FHZ , y _FHZ , ψ _FHZ ) of the motor vehicle ( 6 ) from the desired roadway ( 5 , X _train, y _{web, web} ψ) for a roadway parameters (x, y minimum detectable ψ), the control unit a regulator ( 16 ) and by means of the controller ( 16 ) at least one corrected target steering angle (δ _SOLL ) as a function of the deviation (Δx, Δy, Δψ) can be determined. Device according to claim 1, characterized in that the regulator ( 16 ) comprises a ψ-control, wherein a deviation of the yaw angle (Δψ) can be determined and the corrected target steering angle (δ _SOLL ) in dependence of the deviation of the yaw angle (Δψ) and the ψ-control can be determined. Apparatus according to claim 2, characterized in that the maximum value of the corrected target steering angle (δ _SOLL ) is limited. Device according to claim 1, 2 or 3, characterized in that the regulator ( 16 ) comprises a Y-control, wherein a translational deviation (.DELTA.x, .DELTA.y) of the vehicle can be determined and a corrected desired yaw angle (ψ _SOLL ) as a function of the translational deviation (.DELTA.x, .DELTA.y) and the Y-control can be determined. Apparatus according to claim 4, characterized in that the maximum value of the corrected target yaw rate (ψ _SOLL ) is limited. Device according to one of claims 2 to 5, characterized that the ψ-regulation and / or the Y-control are designed as a PID controller, wherein the gain factor of the proportional component greater than zero is and gains of the Differential and the integral component are greater than or equal to zero. Apparatus according to claim 6, characterized ge indicates that the gain factors can be determined as a function of a vehicle state. Device according to one of claims 1 to 7, characterized in that the desired roadway ( 5 X _train, y _web ψ _web) in a reference coordinate system (x, y) is described. Device according to one of claims 1 to 8, characterized in that by means of a control unit ( 4 ) at the steering of the vehicle an additional steering torque or target steering angle can be applied, wherein by means of the controller ( 16 ) the additional steering torque or target steering angle is determined such that the corrected target road is traveled as accurately as possible. Device according to one of claims 1 to 9, characterized in that at least one sensor ( 2 ) for determining the desired roadway and / or the deviation of the actual roadway of the vehicle from the target roadway as a distance sensor, as Raddrehimpulssensor, as an acceleration sensor, as an angle sensor and / or as a motion sensor is formed. Device according to one of claims 1 to 10, characterized that the determination of the desired travel path adaptive to vehicle tolerances and / or a driver is customizable. A method for assisting a driver when parking a motor vehicle in a parking space or parking bag, wherein at least one segment is calculated at least one reference point for a target road of the motor vehicle in the parking space or parking bag, characterized in that at least in the one reference point a deviation ( Ax, Ay, Δψ) of an actual road (x _FTA, y _FTA, ψ _FTA) of the motor vehicle from the target track (x _train, y _web ψ _train)) for at least one track parameters (x, y, ψ ) and by means of a controller ( 16 ) at least one corrected target steering angle (δ _SOLL ) is determined as a function of the deviation (Δx, Δy, Δψ). Method according to claim 12, characterized in that the controller ( 16 ) comprises a ψ control, wherein a deviation of the yaw angle (Δψ) is determined and the corrected target steering angle (δ _SOLL ) is determined in dependence of the deviation of the yaw angle (Δψ) and the δ-control. A method according to claim 13, characterized in that the maximum value of the corrected target steering angle (δ _SOLL ) is limited. Method according to claim 12, 13 or 14, characterized in that the controller ( 16 ) comprises a Y-control, whereby a translational deviation (Δx, Δy) of the vehicle is determined and a corrected desired yaw angle (ψ _SOLL ) is determined as a function of the translational deviation (Δx, Δy) and the ψ control. A method according to claim 15, characterized in that the maximum value of the corrected target yaw rate (ψ _SOLL ) is limited. Method according to one of claims 13 to 16, characterized that the ψ-regulation and / or the Y-control can be designed as a PID controller, wherein the gain factor of the proportional component greater than zero is and gains of the Differential and the integral component are greater than or equal to zero. Method according to claim 17, characterized in that that the gain factors dependent on a vehicle state. Method according to one of claims 12 to 18, characterized in that the desired roadway is described in a reference coordinate system (x, y) becomes. Method according to one of claims 12 to 19, characterized in that at the steering of the vehicle an additional steering torque or the target steering angle is applied, wherein by means of the controller ( 16 ) the additional steering torque or the desired steering angle is determined such that the corrected target road is traveled as accurately as possible. Method according to one of claims 12 to 20, characterized in that at least one sensor for determining the desired roadway and / or the Deviation of the actual lane of the vehicle from the desired lane as a distance sensor, as a wheel angular momentum sensor, as an acceleration sensor, is designed as an angle sensor and / or as a motion sensor. Method according to one of claims 12 to 21, characterized that the determination of the desired travel path adaptive to vehicle tolerances and / or a driver is adjusted.