DE102016202952A1 - Adaptive torque adjustment for a speed controller - Google Patents

Abstract

The invention relates to a method for a speed regulator (8) for a motor vehicle, wherein a speed specification (v _soll) is adjusted by the driver and automatic control of the speed to the speed specification (v _soll) at least by setting a preset engine torque (M _M) is carried out wherein unsuccessful attempts to overcome an obstacle are monitored and a counter (9) is incremented on each detected attempt, the engine torque command (M _M ) being adjusted in accordance with the count (n).

Description

The invention relates to a method for a speed controller for a motor vehicle, wherein a speed setting is set by the driver and an automatic control of the speed is performed on the speed specification, at least by setting an engine torque setting.

When using speed controllers on uneven terrain, the vehicle may momentarily exceed the preset speed limit at an obstacle, causing the controller to reduce engine torque. The vehicle in such cases does not have enough propulsion to overcome the obstacle and rolls back again. Since the speed controller usually works with permanently set values for engine torque and braking torque, in many cases the same values are set in further attempts to override the obstacle and the vehicle always rolls back again. For the driver, this is uncomfortable.

From the DE 11 2013 005 524 T5 a vehicle speed control system for maintaining a speed at a target speed is known, including a tilt sensor for detecting the inclination of the ground on which the vehicle is traveling, a speed sensor for determining a vehicle speed and an engine control unit for generating a motor torque request signal to a motor / powertrain so to operate, that the vehicle speed is controlled to a target engine speed contains. Such a system has the disadvantage that request signals are generated solely on the basis of the set target speed, the vehicle speed and possibly a slope of the ground. If the vehicle fails to drive over an obstacle, in many cases the next attempt is made with the same request signals, so that another failure can occur. It is therefore an object of the present invention to provide a method which allows a more reliable and comfortable driving over obstacles.

This object is achieved by a method according to claim 1.

Advantageous embodiments of the invention are the subject of the dependent claims.

The invention is based on the consideration that monitoring and taking into account the number of unsuccessful attempts to overcome an obstacle leads to a more suitable setting of the engine torque setting. A counter is incremented at each detected attempt, and the motor torque default is adjusted according to the count. This makes it possible to learn from past unsuccessful attempts and to run over the obstacle without rolling back at the next attempt.

The invention has the advantage that the driver recognizes that the speed controller has recognized the situation and reacts better, resulting in a gain in comfort. Intervention by the driver is avoided.

Advantageously, the engine torque input is increased, the higher the count is. According to a preferred embodiment, the attempts to overcome an obstacle are monitored on the basis of wheel speeds and / or longitudinal acceleration of the motor vehicle. Advantageously, an unsuccessful attempt is detected in reverse rotation of wheels, especially non-driven wheels.

According to a preferred embodiment, the engine torque setting is reduced after a successful overcoming of the obstacle at a predetermined rate, wherein the rate of reduction of the engine torque setting is determined in dependence on the count.

Particularly preferably, the rate of reduction of the engine torque specification is chosen to be lower, the higher the count is. This has the advantage that the engine torque specification remains increased for a longer time, so that possibly occurring directly in the connection further obstacles are approached with a higher engine torque and the probability of overcoming the first attempt for the other obstacles is increased. Preferably, the counter is reset if a successful overcoming of the obstacle is detected.

According to a preferred embodiment, the cruise control is designed for control to speeds below about 30 km / h, in particular for off-road operation. An embodiment of the invention will be explained in more detail with reference to a drawing. In it shows in a highly schematic representation:

1 a schematic diagram of an apparatus for performing an exemplary method.

In 1 a suitable apparatus for performing an exemplary method is shown.

The device contains means 1 for determining a vehicle reference speed v _is based on known methods and means 2 to enter a speed default v _should by the driver. A speed difference Δv between the vehicle reference speed v _is and the speed command v _soll is in the difference images 3 educated. The device also contains means 4 for monitoring a vehicle acceleration a, as well as a sensor 5 for determining a road gradient S and a driving direction determination 6 which determines the direction of travel R of the vehicle based on the directions of rotation of the wheels.

The vehicle reference speed v _is , the speed difference Δv, the vehicle acceleration a, the road gradient S, and the direction of travel R are sent to a monitoring unit 7 which uses this data to monitor attempts to overcome an obstacle. For example, an unsuccessful attempt is detected when the direction of travel R is reverse.

If the monitoring unit has detected an unsuccessful attempt to overcome the obstacle, then a counter 9 incremented.

A speed controller 8th generates on the basis of the speed difference .DELTA.v and the vehicle acceleration a motor torque command M _M , which to an actuator 10 is passed, which controls the engine and adjusts the engine torque according to the engine torque setting M _M. The speed controller 8th takes into account the counter reading n of the counter 9 in that the engine torque input is selected to be higher, for example, according to the higher the counter reading n.

The example method is advantageously used while driving on uneven terrain and using a speed controller, the vehicle, for example, on a step-like obstacle drives. To overcome the obstacle, the speed controller requests an increased engine torque. After the obstacle has been overcome, the speed controller reduces the engine torque setting. Typically, in this situation, the reference speed briefly exceeds the target speed and then drops back to zero or below zero and the vehicle rolls backward. During each override, the speed controller adapts the engine torque setting in such a way that passing over further stages is more comfortable and better because the parameters for calculating the requested engine torque have been optimized.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 112013005524 T5 [0003]

Claims (7)

Method for a speed controller ( 8th )) Is set by the driver for a motor vehicle, wherein a speed specification (v _soll and automatic regulation of the speed to the speed specification (v _soll is performed (M _M)), at least by setting a preset engine torque, characterized in that unsuccessful attempts to overcome a Obstacle to be monitored and a counter ( 9 ) is incremented at each detected attempt, wherein the engine torque setting (M _M ) is adjusted in accordance with the count (s). A method according to claim 1, characterized in that the engine torque input (M _M ) is increased, the higher the count (n) is. Method according to one of the preceding claims, characterized in that the attempts to overcome an obstacle on the basis of wheel speeds (R) and / or a longitudinal acceleration (a) of the motor vehicle are monitored. Method according to one of the preceding claims, characterized in that the motor torque input (M _M ) is reduced after successfully overcoming the obstacle at a predetermined rate and the rate of reduction of the engine torque input (M _M ) is determined in dependence on the count (n). A method according to claim 4, characterized in that the rate of reduction of the engine torque input (M _M ) is chosen to be lower, the higher the count (n). Method according to one of the preceding claims, characterized in that the counter ( 9 ) is reset when a successful overcoming of the obstacle is detected. Method according to one of the preceding claims, characterized in that the speed controller ( 8th ) is designed for a control to speeds below about 30 km / h, in particular for off-road operation.

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