DE102006032671A1 - Method and device for controlling the speed of a vehicle - Google Patents

Abstract

A method and a device (1) for regulating the speed of a vehicle to a desired value (SR) are proposed which make it possible that the regulation of the speed of the vehicle remains active even when cornering. In this case, means (5) for influencing the setpoint value (SR) as a function of at least one variable (Q, G, W) are provided which are characteristic of a lateral dynamics of the vehicle.

Description

State of the art

The The invention relates to a method and a device for Regulation of the speed of a vehicle according to the genus of independent claims out.

method and devices for controlling the speed of a vehicle to a setpoint are already well known.

For example, in the published patent application DE 26 54 455 A1 a device for controlling the driving speed of a motor vehicle described in which a vehicle speed controller on the input side, an actual and a target speed signal is supplied, which outputs a dependent controller output signal.

Disclosure of the invention

The inventive method and the device according to the invention for regulating the speed of a vehicle with the characteristics of independent claims have the opposite Advantage that the setpoint for the speed of the vehicle depends on at least one size will that for a transverse dynamics of the vehicle is characteristic. In this way can control the speed of the vehicle to the lateral dynamics be adapted to the vehicle. Thus, the regulation of speed of the vehicle when cornering not switched off for safety reasons become. The regulation of the speed of the vehicle can thus Even when cornering, maintaining the ride comfort elevated becomes. For example, when driving the vehicle, in particular on highways, the target value for the regulation of the speed of the vehicle will be lowered once detected by the detection and evaluation of values for the at least one size was that the setpoint for the regulation of the speed of the vehicle in a current traversed curve is too high.

The Regulation of the driving speed of the vehicle also remains while cornering is active, but operated at a reduced setpoint.

By in the subclaims listed activities are advantageous developments and improvements of the main claim specified method possible.

In can be easier than for the lateral dynamics of the vehicle characteristic size a lateral acceleration, a yaw rate or a roll angle of the vehicle can be selected.

Advantageous is it, if, in particular dependent from a current actual value of the speed or the setpoint the speed, a first threshold for the at least one size specified will and if at crossing the first predetermined threshold by the at least one size of the setpoint the speed, in particular ramp-shaped, is reduced. To this Way lets the adaptation of the setpoint for the regulation of the speed the vehicle to the lateral dynamics of the vehicle through the threshold comparison particularly simple and inexpensive to implement. By choice of the first predetermined threshold depending on the current actual value the speed or setpoint of the speed can be ensured be that the lateral dynamics of the vehicle in determining the Setpoint for the Regulation of the speed of the vehicle sufficiently considered becomes unwanted vehicle reactions to prevent. By a ramp-shaped reduction of the setpoint this will be for the Driver not as annoying felt.

Advantageous is still, if in the case of several for the lateral dynamics of the vehicle characteristic sizes of Setpoint of the speed is reduced as soon as one of the sizes exceeds its assigned first predetermined threshold. That way also for one during cornering activated vehicle speed control to ensure the highest possible driving safety.

It is furthermore advantageous if the setpoint value of the speed is reduced by a predetermined amount, in particular depending on the deviation of the at least one variable from the first predetermined threshold value and / or depending on the setpoint value or actual value of the speed. The reduction of the setpoint value of the speed by a predetermined amount represents a particularly simple way of reducing the setpoint value of the speed. If this predetermined value is determined as a function of the deviation of the at least one variable from the first predefined threshold value, then the reduction of the setpoint value of the speed can be reduced adapt to the lateral dynamics of the vehicle and thus ensure sufficient driving safety when operating the vehicle speed control even when cornering. If the predetermined amount is determined depending on the setpoint or actual value of the speed, then the lowering of the setpoint value of the speed can also be adapted to the setpoint value or actual value of the speed itself in order to ensure sufficient driving safety. For example, for larger setpoints or actual values, the speed a larger predetermined amount and for smaller setpoints or actual values of the speed, a smaller predetermined amount can be selected.

One Another advantage arises when, in particular depending on current actual value of the speed or the setpoint of the speed second threshold for the at least one size specified which is less than or equal to the first predetermined threshold is, and when falling below the second predetermined threshold by the at least one size of the reduced Setpoint of the maximum speed up to the immediately before the reduction or a new predetermined value, in particular ramp-shaped, is increased. That way on the one hand, make sure that one set before cornering Setpoint for the regulation of the driving speed even after cornering automatically can be adjusted again without it being an action of the Driver needs. On the other hand, this is done in a second predetermined threshold smaller than the first predetermined threshold realized a hysteresis, which is too frequent due to the lateral dynamics the vehicle conditional change prevents the setpoint of the speed. Will the second default Threshold dependent from the current actual value of the speed or the setpoint of the Speed selected, So this has the advantage of increasing the setpoint of the speed a transverse dynamics of the vehicle by means of the second predetermined Threshold based on the current actual value the speed or at the speed setpoint to a danger the driving safety leads.

One Another advantage arises when in the case of several for the lateral dynamics of the vehicle characteristic quantities, the setpoint of the speed elevated will, as soon as all the sizes the fall below its associated second predetermined threshold. This way can also for the increase the setpoint of the speed guarantees the highest possible driving safety become.

drawing

One embodiment The invention is illustrated in the drawing and in the following description explained in more detail. It demonstrate:

1 a functional diagram for explaining the method and apparatus of the invention and

2 a flowchart for an exemplary sequence of the method according to the invention.

Description of the embodiment

In 1 features 1 a device for controlling the speed of a vehicle, such as software and / or hardware implemented, for example, in one or distributed to a plurality of control devices of an engine control of the vehicle. So can the device 1 be implemented in software and / or hardware, for example, in a vehicle dynamics control unit. A speed sensor 10 detects the current speed of the vehicle in a manner known to those skilled in the art, continuously or at discrete times or crank angles, hereinafter also referred to as the actual value I of the speed. The actual value I of the speed is in a first subtraction element 20 subtracted from a corrected setpoint SR of the speed of the vehicle. The resulting difference Δ is a control deviation as a control deviation 25 supplied, the readjusted in the expert manner the actual value I the corrected setpoint SR to minimize the control deviation Δ. From a setpoint specification unit 15 , For example, a cruise control lever is set in the art man known manner, a target value S for the speed of the vehicle. From this setpoint S is in a second subtraction 5 one from an evaluation unit 75 predetermined amount R deducted to form the corrected target value SR, the first subtraction element 20 is supplied.

The device 1 includes a lateral acceleration sensor 30 which measures a lateral acceleration Q of the vehicle continuously or at discrete times or crank angles in a manner known to the person skilled in the art, and the measured values to a first comparison unit 60 forwards. The first comparison unit 60 is from a first threshold memory 45 at least a first predetermined threshold for the lateral acceleration supplied. In addition, the first comparison unit 60 from the first threshold memory 45 optionally also a second predetermined threshold for the lateral acceleration are supplied, which is smaller than the first predetermined threshold value.

Alternatively or as in 1 shown in addition to the lateral acceleration sensor 30 , to the first comparison unit 60 and the first threshold memory 45 is a yaw rate sensor 35 , a second comparison unit 65 and a second threshold memory 50 intended. The yaw rate sensor measures the yaw rate of the vehicle continuously or at discrete times or crank angles in a manner known to the person skilled in the art and passes the measured values to the second comparison unit 65 further. The second comparison unit 65 is from the second threshold memory 50 supplied a first predetermined threshold for the yaw rate. In addition, optionally from the second threshold memory one second predetermined threshold for the yaw rate of the second comparison unit 65 wherein the second predetermined yaw rate threshold is less than the first predetermined yaw rate threshold.

Alternatively or as in 1 shown in addition to the lateral acceleration sensor 30 , and to the first comparison unit 60 , to the first threshold memory 45 and / or the yaw rate sensor 35 , to the second comparison unit 65 , to the second threshold memory 50 is a roll angle sensor 40 , a third comparison unit 70 and a third threshold memory 55 intended. The roll angle sensor 40 detects in a manner known to the skilled person continuously or at discrete times or crank angles a roll angle of the vehicle and forwards the measured values to the third comparison unit 70 further. The third comparison unit 70 is in front of third threshold memory 55 a first predetermined threshold for the roll angle supplied. In addition, the third comparison unit 70 from the third threshold memory 55 optionally a second predetermined threshold value for the roll angle to be supplied, which is smaller than the first predetermined threshold value for the roll angle.

Under lateral acceleration is here to be understood in the direction of the force acting on the vehicle during cornering of the vehicle centrifugal force occurring acceleration of the vehicle. The yaw rate represents the angular velocity of the vehicle about its vertical axis perpendicular to the road and also occurs when cornering. The roll angle is the angle of inclination of the vehicle with respect to the vehicle longitudinal axis, which is tangent to the direction of travel. The roll angle represents the inclination of the vehicle to the roadway which occurs during cornering of the vehicle, which can lead to a tilting of the vehicle when cornering. In the example below 1 Let us assume that both the lateral acceleration and the yaw rate and the roll angle are measured. The first threshold memory 45 is the setpoint S of the setpoint input unit 15 fed. Additionally or alternatively, the first threshold memory 45 the actual value I be supplied to the speed. The second threshold memory 50 is the setpoint S of the setpoint input unit 15 fed. Additionally or alternatively, in the second setpoint memory 50 the actual value I be fed. The third threshold memory 55 is the setpoint S of the setpoint input unit 15 fed. Additionally or alternatively, the third threshold memory 55 the actual value I be fed. In the first threshold memory 45 a characteristic applied, for example, on a test bench is stored, which represents the first predetermined threshold value for the lateral acceleration as a function of the setpoint value S or of the actual value I. The characteristic curve is applied in such a way that, for transverse accelerations Q above the first predetermined threshold value, the setpoint value S has to be corrected in a reducing manner in order to ensure sufficient driving safety. For lateral accelerations Q less than or equal to the first predetermined threshold, however, sufficient driving safety is possible even without reducing intervention on the setpoint S. Thus, for example, for a nominal value S of the driving speed of 150 km / h, a first predetermined threshold value for the lateral acceleration in the range from 0.3 g to 0.4 g can be applied, where g = 9.81 m / s ² . Alternatively, the first predetermined threshold value for the lateral acceleration Q can also be used as the output variable of a characteristic field dependent on the actual value I and the desired value S in the first threshold value memory 45 be stored, this map can be suitably applied in a corresponding manner, for example, on a test area.

The optional in the first threshold memory 45 stored second predetermined threshold for the lateral acceleration Q may also be stored in the form of a characteristic curve depending on the actual value I or the setpoint S, this characteristic may also be applied suitably on a test site. In this case, the second predefined threshold value for all setpoint values S or for all actual values I is smaller than the first predefined threshold value and suitably applied, for example, on a test site such that for lateral accelerations Q smaller than the second predetermined threshold value, the setpoint value S again without reducing intervention by the controller 25 can be adjusted without endangering the driving safety, whereas for the lateral accelerations Q greater than or equal to the second predetermined threshold of the reducing engagement is maintained at the setpoint S, to ensure sufficient driving safety on the one hand and a hysteresis on the other hand, to frequent change of the Intervention on the setpoint S to avoid. The second predetermined threshold value can also be in the first threshold value store 45 be stored in the form of a map depending on both the actual value I and the setpoint S, this map can also be applied appropriately on a test site in a corresponding manner.

In the manner described, in the second threshold memory 50 a first predetermined threshold for the yaw rate depending on the actual value I and / or the setpoint S in the form of a characteristic curve or a map to be stored. Optionally, in the second threshold memory 50 a second predetermined threshold value for the yaw rate may be stored in a corresponding manner depending on the actual value I and / or the desired value S by means of a characteristic curve or a characteristic field.

In the third threshold memory 55 is a first predetermined threshold value for the roll angle W stored in a corresponding manner depending on the actual value I and / or the desired value S in the form of a characteristic curve or a characteristic field. Optionally, in the third threshold memory 55 In addition, a second predetermined threshold for the roll angle W depending on the actual value I and / or the setpoint S by means of a characteristic curve or a map to be stored in a corresponding manner.

The first comparison unit 60 compares the measured lateral acceleration Q with the first predetermined threshold and optionally with the second predetermined threshold for the lateral acceleration and passes the comparison result to the evaluation unit 75 further. The second comparison unit 65 compares the measured yaw rate G with the first predetermined threshold value and optionally with the second predetermined threshold value for the yaw rate and also passes the comparison result to the evaluation unit 75 further. The third comparison unit 70 compares the measured roll angle W with the first predetermined threshold value and optionally the second predetermined threshold value for the roll angle and also passes the comparison result to the evaluation unit 75 further.

As long as the evaluation unit 75 determines that both the lateral acceleration Q is less than or equal to the first predetermined threshold value for the lateral acceleration, and the yaw rate G is less than or equal to the first threshold value for the yaw rate, and the roll angle W is less than or equal to the first predetermined threshold value for the roll angle, So she sets the amount R to zero. Thus, the corrected target value SR is equal to the target value S and there is no correction of the target value input unit 15 delivered setpoint S instead.

However, this puts the evaluation unit 75 determines that the lateral acceleration Q exceeds the first predetermined threshold value for the lateral acceleration or the yaw rate G exceeds the first predetermined threshold value for the yaw rate or the roll angle W exceeds the first predetermined threshold value for the roll angle, then sets the amount R to a value greater than zero , whereby the of the setpoint input unit 15 predetermined setpoint by the amount R is reduced to the corrected setpoint SR.

The amount R can be from the evaluation unit 75 be determined depending on the deviation of the lateral acceleration Q from the first predetermined threshold for the lateral acceleration in the case of exceeding the first predetermined threshold for the lateral acceleration by the lateral acceleration, for example, according to a characteristic. In this case, the amount R of the evaluation unit 75 the larger the said deviation, the greater the choice. In a corresponding manner, the amount R of the evaluation unit 75 be selected depending on the deviation of the yaw rate from the first predetermined threshold for the yaw rate by means of a characteristic, in the event that the yaw rate G exceeds the first predetermined threshold for the yaw rate. Here too, the greater the deviation of the yaw rate G from the first predetermined threshold value for the yaw rate G, the greater the amount R can be chosen.

Furthermore, the evaluation unit 75 determine the amount R, for example, also by means of a characteristic curve depending on the deviation of the roll angle W from the first predetermined threshold for the roll angle, for the case that the roll angle W exceeds the first predetermined threshold for the roll angle. In this case, the larger the deviation of the roll angle W from the first predetermined threshold value for the roll angle, the greater the amount R can be selected.

The lateral acceleration Q, the yaw rate G and the roll angle W are characteristic variables for the lateral dynamics of the vehicle. If more than two of these variables exceed their assigned first predetermined threshold value, then the evaluation unit 75 also select the amount R by means of a map or a characteristic space depending on the deviation of the respective exceeding of the corresponding first predetermined threshold value, wherein the amount R is selected the greater, the greater the corresponding deviations from the first predetermined threshold value. Additionally or alternatively, the amount R of the evaluation unit 75 in the case of exceeding at least a first predetermined threshold by the associated, the lateral dynamics of the vehicle characterizing size Q, G, W are also dependent on the setpoint S and / or dependent on the actual value I selected, for example, the amount R as a fraction of the actual value I or the setpoint value S or an average value of actual value I and setpoint value S from the evaluation unit 75 be specified. For this purpose, the evaluation unit 75 the setpoint S, additionally or alternatively, the actual value I supplied. The fraction of the actual value I or the setpoint value S or the mean value of the actual value I and the setpoint value S can be fixed or selected depending on the mentioned deviations of the size or quantities Q, G, W characterizing the transverse dynamics of the vehicle exceeding its first predetermined threshold value , Thus, with increasing deviation or with increasing deviations of the size or quantities Q, G, W characterizing the lateral dynamics of the vehicle, the named fraction may be chosen to be larger. The relationship between the size of the fraction for the amount R and the size of the deviation of the For the transverse dynamics of the vehicle characteristic size or sizes Q, G, W of their first predetermined threshold can be applied according to a characteristic curve, a map or a license, for example, on a test area.

Furthermore, it can be provided that the evaluation unit 75 the amount R not immediately but according to a predetermined function, for example, builds ramp-shaped or by successive incrementation at its output to make the withdrawal of the setpoint S as comfortable as possible.

In the event that in the threshold stores 45 . 50 . 55 also the respective second predetermined threshold value is stored, the evaluation unit checks 75 after formation of the amount R, whether all the transverse dynamics of the vehicle characterizing variables Q, G, W each fall below their assigned second predetermined threshold value. Only when this is the case, the evaluation unit reduces 75 the amount R again. Here, the second predetermined threshold for the lateral acceleration Q is less than or equal to the first predetermined threshold for the lateral acceleration, the second predetermined threshold for the yaw rate G less than or equal to the first predetermined threshold for the yaw rate and the second predetermined threshold for the roll angle W smaller or be chosen equal to the first predetermined threshold for the roll angle. In the event that the second predetermined threshold value of a variable characterizing the lateral dynamics of the vehicle is chosen to be smaller than the first predetermined threshold value for this quantity, a hysteresis for the formation and re-withdrawal of the amount R with respect to this variable is realized, otherwise not. In this case, the second predefined threshold value for one or more variables Q, G, W characterizing the lateral dynamics of the vehicle can be selected, for example, by a predetermined distance smaller than the corresponding first predefined threshold value, with decreasing actual value I or decreasing setpoint value S this distance becoming smaller, The second predetermined threshold value is therefore also formed as a function of the actual value I or of the setpoint value S in accordance with a characteristic curve applied, for example, to a test site. The distance between the first predefined threshold value and the second predefined threshold value for one or more variables or variables characterizing the transverse dynamics of the vehicle can be applied, for example, depending on the actual value I or the setpoint value S, so that the withdrawal of the amount R occurs only if Sufficient driving safety is ensured and on the other hand, a sufficient hysteresis is ensured.

Of the first predetermined threshold and / or the second predetermined threshold for one or for several variables Q, G characterizing the lateral dynamics of the vehicle W can alternatively be dependent from the mean value of the actual value I and the desired value S in each case according to a Characteristic be applied in a corresponding manner.

Also, the withdrawal of the amount R by the evaluation unit 75 can again according to a predetermined function, for example, ramped or by successive decrement in order to influence the ride comfort as little as possible. If, during the withdrawal of the amount R, one of the first predefined threshold values is exceeded by the assigned variable Q, G, W characterizing the lateral dynamics of the vehicle, the withdrawal of the amount R from the evaluation unit becomes 75 stopped and a new amount R according to the procedure described above by the evaluation unit 75 built up.

2 shows a flowchart for an exemplary sequence of the method according to the invention.

After the start of the program will be at a program point 100 from the set point detection unit 15 the setpoint S for the driving speed determined. Subsequently, becomes a program point 105 branched.

At program point 105 is dependent on the setpoint S, the first predetermined threshold and the second predetermined threshold for the lateral acceleration Q, the yaw rate G and the roll angle W in each associated threshold value memory 45 . 50 . 55 determined and to the respectively associated comparison unit 60 . 65 . 70 forwarded. A dependence of the first predetermined threshold value and the second predetermined threshold value for the variables Q, G, W characterizing the lateral dynamics of the actual value I should not be assumed in this example. Subsequently, becomes a program point 110 branched.

At program point 110 The lateral acceleration Q from the lateral acceleration sensor 30 , the yaw rate G from the yaw rate sensor 35 and the roll angle W from the roll angle sensor 40 detected. The lateral acceleration Q is sent to the first comparison unit 60 , the yaw rate G to the second comparison unit 65 and the roll angle W to the third comparison unit 70 forwarded. Subsequently, becomes a program point 115 branched.

At program point 115 checks the evaluation unit 75 based on the signals of the comparison units 60 . 65 . 70 whether the detected lateral acceleration Q is greater than the first predetermined threshold value for the Transverse acceleration or the detected yaw rate G is greater than the first predetermined threshold value for the yaw rate or the detected roll angle W is greater than the first predetermined threshold value for the roll angle. If this is the case, then becomes a program point 120 branches, otherwise becomes program point 100 Branched back.

At program point 120 initiates the evaluation unit 75 the formation of the amount R for reducing the target value S in the manner described. Subsequently, becomes a program point 125 branched.

At program point 125 becomes a new measured value for the lateral acceleration Q from the lateral acceleration sensor 30 , for the yaw rate G from the yaw rate sensor 35 and for the roll angle W from the roll angle sensor 40 detected. The detected value for the lateral acceleration Q becomes the first comparison unit 60 , the detected value for the yaw rate G of the second comparison unit 65 and the detected value for the roll angle W of the third comparison unit 70 fed. The first comparison unit 60 In addition, the first and the second predetermined threshold value for the lateral acceleration Q are supplied. The second comparison unit 65 In addition, the first and second predetermined threshold values for the yaw rate G are supplied. The third comparison unit 70 are also the first and the second predetermined threshold for the roll angle W supplied. Subsequently, becomes a program point 130 branched.

At program point 130 checks the evaluation unit 75 based on the signals of the comparison units 60 . 65 . 70 whether the detected value for the lateral acceleration Q is smaller than the second predetermined threshold value for the lateral acceleration and whether the detected value for the yaw rate G is smaller than the second predetermined threshold value for the yaw rate and if the detected value for the roll angle W is smaller than that second predetermined threshold for the roll angle are. If this is the case, then becomes a program point 135 branches, otherwise becomes program point 125 branches back and each detected a new measured value for the lateral acceleration Q, for the yaw rate G and for the roll angle W.

At program point 135 leads the evaluation unit 75 the amount R ramp-shaped or by means of a decrementing step in the direction of the value zero or a deviating new predetermined value, for example, to achieve a meantime changed setpoint S back. Afterwards, the program is left and can be run through immediately afterwards.

As described the invention also only under evaluation of two of the said Transverse dynamics of the vehicle characterizing variables Q, G, W or only one the lateral dynamics of the vehicle characterizing quantities Q, G, Realize W in a similar manner.

The amount R is from the evaluation unit 75 in the case of the return is returned to the value zero, if the return operation is not stopped as described above and a new amount R is established.

The formation of the amount R is equivalent to the specification of a new setpoint compared to that of the setpoint detection unit 15 predetermined setpoint S is reduced and corresponds to the corrected setpoint SR.

Claims (10)

Method for regulating the speed of a vehicle to a setpoint value (S), characterized in that the setpoint value (S) is influenced as a function of at least one variable (Q, G, W) which is characteristic of a lateral dynamics of the vehicle. Method according to claim 1, characterized in that that as a first for the lateral dynamics of the vehicle characteristic size one Lateral acceleration (Q) of the vehicle is selected. Method according to one of the preceding claims, characterized characterized in that as a second for the lateral dynamics of the vehicle characteristic size one Yaw rate (G) of the vehicle is selected. Method according to one of the preceding claims, characterized characterized in that as a third for the lateral dynamics of the vehicle characteristic size a roll angle (W) of the vehicle is selected. Method according to one of the preceding claims, characterized characterized in that, in particular depending on a current actual value (I) the speed or the setpoint (S) of the speed, a first threshold for the at least one size (Q, G, W) is specified and that when exceeded the first predetermined threshold by the at least one Size (Q, G, W) the setpoint (S) of the speed, in particular ramp-shaped reduced becomes. A method according to claim 5, characterized in that in the case of several characteristic of the transverse dynamics of the vehicle variables (Q, G, W), the setpoint (S) of the speed is reduced, as soon as one of the variables (Q, G, W) to her ordered first predetermined threshold exceeds. Method according to claim 5 or 6, characterized that the setpoint (S) of the speed by a predetermined Amount (R), in particular dependent from the deviation of the at least one size (Q, G, W) from the first predetermined one Threshold and / or dependent from the setpoint (S) or the actual value (I) of the speed is lowered. Method according to one of claims 5 to 7, characterized that, in particular dependent from the current actual value (I) of the speed or the setpoint (S) the speed is a second threshold for the at least a size (Q, G, W) is given, which is less than or equal to the first predetermined Threshold is, and that falls below the second predetermined Threshold by the at least one size (Q, G, W) of the reduced Setpoint (SR) of the speed maximum up to the immediate before the reduction or a new predetermined value (S), in particular ramp-shaped, is increased. Method according to claim 8, characterized in that that in case of several for the lateral dynamics of the vehicle characteristic quantities (Q, G, W) the reduced speed setpoint (SR) is increased, as soon as all the sizes (Q, G, W) fall below the second predetermined threshold assigned to it. Contraption ( 1 ) for controlling the speed of a vehicle to a desired value (S), characterized in that means ( 5 ) are provided for influencing the setpoint value (S) as a function of at least one variable (Q, G, W) which is characteristic of a lateral dynamics of the vehicle.