GB2482384A

GB2482384A - A method of limiting parking speed using a steering wheel rotational speed

Info

Publication number: GB2482384A
Application number: GB1111671.2A
Authority: GB
Inventors: Michael Seiter; Florian Raisch; Benoit Mangin; Jochen Staack
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2010-07-08
Filing date: 2011-07-07
Publication date: 2012-02-01
Anticipated expiration: 2031-07-07
Also published as: FR2962393A1; GB2482384B; DE102010031122A1; GB201111671D0

Abstract

A method of supporting a driver of a motor vehicle in a driving manoeuvre, such as moving into or out of a parking space, comprises selecting the vehicle speed of moving into or out of the parking space. The vehicle speed is selected via a human machine interface such as a lever, according to individual wishes of a driver. At least the parking speed is limited through a maximum speed of rotation Ï max of a steering wheel of the motor vehicle. Rotational speed max is calculated during parking using a predetermined mathematical relationship which includes vehicle wheelbase constant and a clothoid parameter constant. The parking speed is selected from various stages which are activated by actuating an accelerator or brake pedal.

Description

Description Title

Device for selecting the parking speed

Prior art

DE 10 2004 044 777 Al relates to a method for supporting the driver of a motor vehicle in a parking manoeuvre,, and to a device for executing this method. In the case of the parking manoeuvre, an object present in the travel path of the motor vehicle is recognized as an obstacle, and the distance between the motor vehicle and the obstacle is determined as an obstacle distance. The speed of the motor vehicle is controlled in dependence on the wish of the driver and in dependence on the obstacle distance. A speed limitation curve is set in dependence on the obstacle distance, the speed of the motor vehicle being limited to a value at or below the speed limitation curve value.

DE 10 2005 008 176 Al relates to a device for semi-autonomously supporting the parking operation in the case of motor vehicles. A unit for determining a suitable parking path is provided, as well as means for determining the position of the vehicle, and means for determining the speed of the vehicle. A control unit is designed in such a way that, the speed of the vehicle being otherwise manually controlled, this control device is designed to actuate a device for automatically reducing the speed of the vehicle during a parking operation if the speed of the vehicle, in respect of at least one set parameter, is too high. The control unit has the effect that, the speed of the vehicle being otherwise manually controlled, during the parking manoeuvre prompts are output to the driver steering the vehicle, with the aim of causing the driver to reduce the speed of the vehicle if the speed of the vehicle, in respect of a set parameter, appears too high.

DE 2008 006 054 Al relates to a device for executing an automatic braking intervention during a semi-autonomous parking operation. According to this solution, a unit is provided for determining a suitable parking trajectory, as well as means for executing an automatic steering intervention for the purpose of following the determined parking trajectory. A control unit comprises speed regulating means, the control unit limiting the vehicle speed, by means of the regulating means, if a set limit speed of the vehicle is attained. The control unit uses the regulating means to limit the vehicle speed only if the set limit speed is attained and at least one further condition is fulfilled; in particular, the control unit uses the regulating means to limit the vehicle speed if a set limit speed has been attained and the accelerator pedal has not been actuated.

Semi-automatic parking in parallel parking spaces, i.e. parking spaces that extend between vehicles ranged in succession along a kerb, is at present offered by some motor vehicle manufacturers. In the case of such semi-automatic parking assistance systems, during the forward travel an ultrasound sensor attached to the side of the vehicle gauges the distance in relation to objects next to the vehicle. The determined signal profile is used to identify whether, and where relative to the vehicle, there is a suitable parking space.

If parking is effected in a parking space determined in such a manner, beginning with a reverse move, the parking assistance system takes over the steering operation, while the driver only has to actuate the brake and the accelerator pedal. In this case, the steering intervention by the parking assistance system is effected in such a way that the parking motor vehicle both steers past the objects that bound the parking space and -particularly in the case of advanced systems -at the end, the vehicle stands parallel to the carriageway boundary, thus, for example, the kerb. In a variant, the driver himself still has to steer, but the parking assistance system informs him through appropriate prompts, thus, for example, through graphical symbols in the multifunction instrument, how the driver must steer in each case. These prompts relate to a full lock, a partial lock and to the steering direction, i.e. to the left or to the right, in order to successfully enter the parking space.

In a further, advanced development stage of such parking assistance systems, support is also provided for longitudinal guiding by means, for example, of (transversely guided and longitudinally guided) parking occurring with braking intervention. The braking intervention in this case is effected, for example, by means of braking instructions from parking assistance systems to an ESP system such as, here, a CRN network.

In this case, the speed can also be limited during the parking operation. This means that the driver, by contacting the accelerator pedal of the vehicle, is unable to accelerate beyond a maximum speed. However, the maximum allowable speed can change during the course of the parking operation. A comfortable parking speed is somewhat highly subjective, however, and depends greatly on the driver.

Some drivers like to drive into the parking space as fast as the system allows, while others, in turn, like to drive relatively slowly, in order to feel safe. Most drivers, in the first parking attempt, wish to select a speed that is slower than the possible speed set by the system, this being due, not least, to the effects of familiarization in the use of such parking systems. Normally, after a phase of habituation to a longitudinally guided parking system, higher parking speeds are wanted.

Disclosure of the invention

According to the invention, it is proposed that the driver, according to individual wishes, uses a HMI (human-machine interface), thus, for example, an on-board computer, a rotary or selector lever, a pedal, a monitor or the like, to select a speed of moving into or out of a parking space.

It is therefore possible, in the context of a convenience parking assistance system, in particular for longitudinally guided parking, to take account of the personal safety requirements of the driver, such that the latter feels comfortable and does not experience a situation of stress.

The speed of moving into or out of a parking space is limited upwardly, in a controlling manner, through the speed of rotation Cmax of the steering wheel. For the maximum vehicle speed vmax of a motor vehicle during parking, the following applies: max -i XCOmax wiiereln 1 constant, wheelbase of the vehicle, and A constant, clothoid parameter.

A software implemented in the on-board computer is used to ensure that a system-based maximum speed is not exceeded.

The parking speed can be selected, for example, from a group of set, previously defined speed stages. In the simplest case, the speed stages comprise a first level, and a second level, between which selection can be made. The parking speed depends greatly, on the one hand, on the respective section of the manoeuvre into or out of a parking space, arid also, on the other hand, on statutory regulations. Thus, the parking speed is between 1 km/h and km/h. In the case of a straight portion of reverse travel, it is possible to travel faster than, for example, during a steering operation. Generally, it is the case that steering interventions may only occur up to a speed of km/h. In the case of the solution proposed according to the invention, it is possible to select a first speed stage, which represents a slow speed, thus, for example, between 1 km/h and 3 km/h, and additionally a second speed stage, which represents a medium speed, which can be, for example, between 4 km/h and 6 km/h, as well as a further, third speed stage, which represents a higher speed, which is between, for example, 7 km/h and 10 km/h.

The speed to be selected for the parking operation that corresponds most closely to the individual comfort of the driver can be selected, for example, from three speed stages. For example, the respective speed stage can be selected via the pedal system, thus, for example, the brake pedal or the accelerator pedal of the motor vehicle. If, for example, before actuation of the accelerator pedal, the speed stage representing a medium speed is active, switchover to the third speed stage can be effected, for example, by actuating the accelerator pedal. If the third speed stage, representing a higher speed, has been selected, and the accelerator pedal is actuated, the third speed stage is maintained.

If, on the other hand, the brake pedal is actuated and the third speed stage had been selected before actuation of the brake pedal, switching down to the second speed stage is effected. If this speed stage is active and the brake pedal is actuated again, switching down from the second speed stage to the first speed stage is effected. If, on the other hand, the latter is active and the brake pedal is actuated, the third speed stage is maintained.

Embodiment variants The present invention is implemented in the context of a parking assistance system, in particular for longitudinally guided parking, and takes account of the personal safety requirements of individual drivers. Using the method proposed according to the invention, the driver of the motor vehicle can select, according to the driver's individual safety requirements, the speed stage in which an operation for moving into and, if applicable, out of a parking space is to be conducted, in such a way that the driver feels comfortable and is also safely in command of the vehicle.

Following the solution proposed according to the invention, the selection of the speed of moving into a parking space and, if applicable, the speed of moving out of a parking space is effected via a human-machine interface (HMI) such as, for example, an on-board computer, a rotary lever, a selector lever, similar to that for an automatic transmission, or the like. It is thereby possible to regulate the parking speed, particularly in the case of a longitudinally guided parking system, this being able to be effected either steplessly or in defined speed stages that can be accessed by the driver as required. In the implementation of the solution proposed according to the invention, there is additionally the possibility of configuring this implementation such that a parking speed is not changed during the execution of a parking manoeuvre; on the other hand, the possibility also exists to vary the parking speed during the execution of a parking manoeuvre by means of a longitudinally guided parking assistance system, during the execution of the parking operation.

In the case of the method proposed according to the invention being implemented in an on-board computer, it is ensured that a system-based maximum speed of approximately km/h is not exceeded. The speed of moving into a parking space and, if applicable, also the speed of moving out of a parking space is limited upwardly, in a controlling manner, through a maximum speed of rotation max of the steering wheel of the motor vehicle. For the maximum vehicle speed Vmax during the operation of moving into or, also, out of a parking space, the following applies: It v _Ax max -I max' werein 1 constant, wheelbase of the vehicle, and A = constant, clothoid parameter.

If the method proposed according to the invention is implemented, for example, in an on-board computer, the method proposed according to the invention comprises at least -this applies to the simplest case -a first speed stage, and a second speed stage that differs from the latter. The speed of a longitudinally guided manoeuvre such as, for example, moving into or out of a parking space, depends on the respective section of the manoeuvre to move into or out of the parking space. In the case of a straight portion of reverse travel, it is possible to travel faster than, for example, during the period of a steering operation. Generally, it is the case that steering interventions may only occur up to a speed of km/h.

In a preferred embodiment variant of the method proposed according to the invention, the pedal system, i.e. the brake pedal and the accelerator of the motor vehicle, is connected to the on-board computer in such a way that particular speed stages for parking are selected through actuation of the pedals such as, for example, the brake pedal or the accelerator pedal of the motor vehicle. For this purpose, advantageously, at least three differing speed stages can be defined, namely, a first, a second and a third speed stage. The first speed stage thus represents, for example, a relatively low speed level, of between 1 km/h and 6 km/h, while the second speed stage a II represents, for example, a medium speed level that extends, for example, between 4 km/h and 6 km/h. On the other hand, the third speed level that can be selected for conducting parking operations is a stage that represents a higher speed level, which is, for example, between 7 km/h and km/h.

If the accelerator pedal or brake pedal is actuated while a manoeuvre for moving into or out of a parking space is being performed, the following is then achieved, according to the actuation of the accelerator pedal: If the second speed stage is already active and the accelerator pedal is actuated, switching up to the third speed stage is effected. In this case, an operation for moving into or out of a parking space proceeds at the highest level of parking speed that is allowable within the scope of the method proposed according to the invention, taking account of the maximum vehicle speed vmax. If, during a parking manoeuvre, the third speed stage is already active and the accelerator pedal is actuated again, the third speed stage is maintained. The parking operation is not performed with a further increase in the speed level. The third speed level is maintained in this case.

If the brake pedal of the motor vehicle is actuated, the following sequence is effected: If the third speed stage is active when the brake pedal of the motor vehicle is actuated by the driver, switching back to the second speed stage is effected upon actuation of the brake pedal. If the brake pedal is actuated again and the third speed stage is active, a further switchover operation is effected, to the first speed stage. If the first speed -10 stage is already active and the brake pedal is actuated again, the first speed stage is not altered, but is maintained. There is no further slowing of the motor vehicle during the parking operation since, by definition, the first speed stage constitutes the lowest speed stage.

Clearly, the selection described above on the basis of three parking speed levels can also performed in further speed stages that are other than the three speed stages mentioned above. Thus, for example, gradations into five or seven differing speed stages for moving into or out of a parking space are conceivable.

Besides a selection to be made by the driver, according to individual safety requirements, from the selection possibility outlined exemplarily above, the method proposed according to the invention can be implemented in such a way that a speed of moving into or out of a parking space during a parking manoeuvre can also be regulated in a stepless manner by means of a rotary knob or the like.

Thus, for example, the possibility exists, in the case of an intervention performed in respect of the steering lock on the steering wheel, in the case of actuation of a rotary knob, to abruptly reduce the parking speed, through actuation of the selector lever, during approach to an identified obstacle, or to accelerate the operation of moving out of a parking space according to the actuation of a stepless rotary knob.

If a discrete selection is performed between a plurality of set speed stages for parking, this selection can be made in such a way that a basic setting, for example fixed by one of the speed stages, thus, for example, the second speed -11 -stage, is implemented, for example, in the on-board computer. As a result, a parking speed would then be fixed, and this could not be changed during the parking operation. The situation would differ from the implementation of a stepless parking speed preselection, by means of which the speed of moving into or out of a parking space can be reduced or increased during the parking manoeuvre.

The method, proposed according to the invention, for selecting a speed for moving into or out of a parking space can also be realized in such a way that this method is realized as a learning system that, for example, on the basis of the size of the parking space determined by sensor means, already sets a particular speed stage for parking, thus, for example, the third speed stage, for the case of a parking space appearing to be sufficiently large, taking account of the outer dimensions of the motor vehicle, and no obstacles being in the way. On the other hand, the system can also be configured, for example by the driver of the vehicle, in such a way that the driver individually sets his preferably selected parking speed according to the stage that matches that speed and -depending on the size of the available parking space -the parking is executed with the driver's personal, individual speed level being taken into account. If, on the other hand, the parking assistance system for longitudinally guided parking identifies that the dimensions of the available parking space just correspond to the dimensions of the motor vehicle, i.e. there is consequently little room available for executing manoeuvres, then, in the case of the method proposed according to the invention being implemented accordingly, a lower speed stage can already be selected by -12 -the on-board computer or the HNI (human-machine interface), such that the subjective safety perception of the driver is increased, and the latter is not subjected to a situation of stress.

In the case of the method proposed according to the invention, possible collisions can also be indicated by acoustic or optical signals, for which purpose, for example, the CAN bus of a motor vehicle could be used. In the case of the solution proposed according to the invention, the vehicle is braked to a standstill at the end of the parking move, in order thus to avoid a collision with an object bounding the parking space. In the case of the solution proposed according to the invention, advantageously, a semi-automatic system, in particular for left parking, is proposed, wherein the driver himself assumes the longitudinal guiding, this being effected through actuation of the brake pedal or the accelerator, but wherein the driver is relieved of selection of the corresponding steering lock, but being able to select an individual parking speed appropriate to his safety requirements.