SUSPENSION SYSTEM OF A VEHICLE

TECHNICAL BACKGROUND

The invention concerns a method for controlling the suspension system of a vehicle according to the preamble in Claim 1 . The invention also concerns a system for controlling the suspension system of a vehicle. The invention also concerns a motor vehicle. The invention further concerns a computer program and a computer program product.

BACKGROUND

Road-holding ability, driving performance and comfort are important parameters in relation to motor vehicles, including buses. To improve road- holding ability, driving performance and comfort, vehicles are equipped with suspension systems, which are arranged so as to protect the vehicle, passengers and cargo against injury, damage and wear and tear. A suspension system comprises suspension elements to keep the vehicle on the proper level as well as to absorb shocks, so that irregularities in the underlying surface do not propagate to the body of the vehicle, plus damping elements to damp vibrations and rolling and swaying of the vehicle body.

Recent years have seen the development of more active suspension systems that adapt to the current status of the vehicle. A so-called semi- active suspension system is arranged so as to control the damping, while the suspension is not variable, or alternatively, arranged so as to control the suspension, while the damping is not variable. An active suspension system is designed to control both damping and suspension. US20050017462 comprises a controllable suspension system of a vehicle wherein a number of sensors measure road-related variations around a vehicle and control the vehicle suspension accordingly. OBJECT OF THE INVENTION

One object of the present invention is to create a method and a system for controlling the suspension system of a vehicle that enables, in a time- effective manner, the vehicle to travel safely and with good road-holding and comfort.

SUMMARY OF THE INVENTION

This and other objects that will be presented in the description below are achieved by means of a method, a system and a motor vehicle, a computer program and a computer program product of the kinds specified in the introduction hereto, and which further exhibit features specified in the characterizing parts of the accompanying independent claims. Preferred embodiments of the method and the system are defined in the accompanying dependent claims.

According to the invention, these objects are achieved by means of a method for controlling the suspension system of a vehicle that comprises the steps of controlling the suspension system while taking into account a passenger perspective that includes taking considerations of passenger comfort into account. It thereby becomes possible to improve passenger comfort during forward travel of the vehicle, which, according to one variant, consists of a bus. Controlling the suspension system in this way enables faster and thus more time-effective transport of the vehicle with its passengers, while maintaining or improving passenger comfort. Passenger safety is also enhanced, in that the risk that passengers, such as standing passengers or wheelchair-bound passengers in a bus, will injure themselves during forward travel of the vehicle is reduced. As a result, the movements of the vehicle body can be controlled from the standpoint of passenger comfort and safety. According to one embodiment, the method further comprises the step of determining the existing passenger distribution and passenger situation in the vehicle as a basis for controlling the suspension system. By taking into account the passenger distribution, such as where in the vehicle, for example a bus, the passengers are located, as well as the passenger situation, such as whether a passenger is standing, sitting, sitting in a wheelchair, lying in a baby carriage or the like, the control of the suspension system can be adapted to the passenger distribution and passenger situation, thereby enhancing the comfort and safety of the passengers and enabling faster and more time-effective transport of the vehicle with its passengers while maintaining or improving their comfort. Consequently, it is thereby made possible to control the suspension system in such a way that the passengers are collectively subjected to as uniform an acceleration experience as uniform as possible in different directions, for example in the z-direction, i.e., in the vertical direction, when driving over irregularities in the road and/or the x-direction, i.e., in the longitudinal direction of the vehicle, during acceleration or retardation. It is further made possible to control the suspension system so that the passengers experience at least some positive acceleration in the y- direction, i.e., in the widthwise direction of the vehicle, during cornering for a more comfortable experience.

According to one embodiment, the method comprises the step of determining direction changes as a basis for controlling the suspension system. This makes it possible to further optimize the control so as to enhance passenger comfort during forward travel of the vehicle, so that passenger comfort and passenger safety are enhanced during cornering, evasive maneuvers, hill- cresting/bump absorption or corresponding direction changes of the vehicle, so that the rotations and accelerations to which the passengers are subjected are reduced. This makes it possible to control the suspension system so that the passengers experience at least some positive acceleration in the y- direction during cornering, for a more comfortable experience.

According to one embodiment, the method comprises the step of determining changes in velocity as a basis for controlling the suspension system. This makes it possible to further optimize the control so as to enhance passenger comfort during forward travel of the vehicle. According to one embodiment, the method comprises the step of determining the velocity as a basis for controlling the suspension system. This makes it possible to further optimize the control so as to enhance passenger comfort during forward travel of the vehicle.

According to one embodiment, the method further comprises the step of determining an anticipated passenger distribution and passenger situation in the vehicle using a model for the behavior of a given passenger population as a basis for controlling the suspension system. This enables control of the suspension system that is adapted to the passenger distribution and passenger situation so as to enhance passenger comfort and safety, thus enabling faster and more efficient transport by the vehicle with its passengers while maintaining or enhancing passenger comfort.

According to one embodiment, the method comprises the step of controlling the suspension system so as to achieve a certain inclination of the vehicle in order to obtain a sloping effect in connection with direction change in the form of cornering. The suspension system is thereby controlled in such a way that the passengers experience at least some positive acceleration in the y- direction during cornering, for a more comfortable experience. Controlling the suspension system in this way during cornering enhances passenger comfort and safety, enabling faster and more efficient transport by the vehicle with its passengers while maintaining or enhancing passenger comfort. For example, in this way a bus with standing passengers can be driven faster into a curve without the risk that the standing passengers will fall. Inclining the vehicle to obtain a sloping effect during cornering is, according to one variant of the vehicle in which the suspension system includes an air suspension system, such as in a bus, achieved by activating a level-adjusting function of the vehicle. According to one embodiment, the method comprises the step of controlling the suspension system so as to achieve a given inclination of the vehicle to achieve a reduction in the acceleration effect in the vertical direction in connection with direction change in the form of hill-cresting/bump absorption. According to the invention, the objects are achieved by means of a system for controlling the suspension system of a vehicle comprising means for controlling the suspension system while taking into account a passenger perspective that includes taking considerations of passenger comfort into account. According to one embodiment, the system further comprises means for determining the existing passenger distribution and passenger situation in the vehicle as a basis for controlling the suspension system.

According to one embodiment, the system comprises means for determining direction changes as a basis for controlling the suspension system. According to one embodiment, the system comprises means for determining velocity changes as a basis for controlling the suspension system.

According to one embodiment, the system comprises means for determining the velocity as a basis for controlling the suspension system.

According to one embodiment, the system comprises means for determining an anticipated passenger distribution and passenger situation in the vehicle using a model for the behavior of a given passenger population as a basis for controlling the suspension system.

According to one embodiment, the system comprises means for controlling the suspension system so as to achieve a given inclination of the vehicle to achieve a sloping effect in connection with direction change in the form of cornering. According to one embodiment, the system comprises means for controlling the suspension system so as to achieve a given inclination of the vehicle to achieve a reduction in an acceleration effect in the vertical direction during a direction change in the form of hill-cresting/bump absorption. The system claims exhibit advantages corresponding to the advantages described above for corresponding method claims.

DESCRIPTION OF FIGURES

The present invention will be better understood with reference to the following detailed description read in conjunction with the accompanying drawings, wherein the same reference designations refer to the same parts consistently throughout the many views, and in which:

Fig. 1 schematically illustrates a motor vehicle according to one embodiment of the present invention; Fig. 2 schematically illustrates a system for controlling the suspension system of a vehicle according to one embodiment of the present invention;

Fig. 3 schematically illustrates a block diagram of a method for controlling the suspension system of a vehicle according to one embodiment of the present invention; and Fig. 4 schematically illustrates a computer according to one embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS The term "link" refers herein to a communication link, which can be a physical line, such as an opto-electronic communication line, or a non-physical line, such as a wireless connection, e.g. a radio or microwave link.

Fig. 1 schematically illustrates a motor vehicle 1 according to one embodiment of the present invention. The exemplary vehicle 1 consists of a heavy vehicle in the form of a bus. The vehicle can alternatively consist of any arbitrary suitable vehicle. The vehicle contains a controllable suspension system 200. The vehicle contains a system I according to the present invention. Fig. 2 schematically illustrates a block diagram of a system I for controlling the suspension system 200 in a vehicle according to one embodiment of the present invention.

The suspension system 200 can consist of any arbitrary suitable suspension system for active/semi-active suspension/damping. According to one variant, the suspension system 200 comprises an air suspension system containing air suspension elements. Said air suspension elements comprise one or more air suspension elements arranged on the right side, preferably in association with the respective wheel axle of the vehicle, and one or more air suspension elements arranged on the left side, preferably in association with the respective wheel axle.

Respective air suspension elements are arranged between the vehicle frame and the respective axle, whereupon the vehicle can be raised and lowered by regulating the air in said air suspension elements. Raising and lowering of the vehicle/vehicle frame includes raising/lowering each respective side of the vehicle and raising/lowering the front and rear of the vehicle.

The air suspension system further comprises an air valve configuration connected to said air suspension elements and arranged so as to control the air pressure in the respective air suspension elements and air pressure source configuration in order to supply the air valve configuration with air.

Respective air suspension elements comprise a pressure sensor element arranged so as to sense the air pressure in the air suspension element. According to one variant, said air suspension elements consist of bellows units or comprise bellows units.

According to one variant, said first, second, third and fourth air suspension elements are separate units, so that raising and lowering by means of the respective air suspension elements can occur individually, i.e. for each respective wheel. According to this variant, lateral raising and lowering, front and rear raising and lowering and combinations thereof are thus enabled.

According to one variant, the suspension system 200 comprises an electric suspension system, which, according to one variant, includes linear motors arranged so as to handle the level maintenance and suspension/damping of the vehicle. Linear motors have rapid response, and thus enable rapid compensation in connection with the control of such a suspension system.

According to one variant, the suspension system 200 comprises a hydropneumatic suspension system.

According to one variant, the suspension system 200 comprises an electromagnetic suspension system.

The system I comprises an electronic control unit 100 for said control of the suspension system 200.

The system I comprises means for determining direction changes of the vehicle as a basis for controlling the suspension system 200. Direction changes can include direction changes during cornering, on bumps, hills, evasive maneuvers or the equivalent. According to one variant, the means for determining direction changes include rotation sensor elements. According to one element, said rotation sensor elements include lateral acceleration elements. According to one variant, the means for determining direction changes comprise acceleration elements for determining the acceleration in the vertical direction. The system I comprises means 120 for determining velocity changes of the vehicle as a basis for controlling the suspension system 200. The means 120 for determining velocity variations include acceleration elements such as accelerometers.

The system I comprises means 130 for determining the velocity of the vehicle as a basis for controlling the suspension system 200. According to one variant, said means 130 for determining vehicle velocity include speedometer elements.

The system I comprises means 140, 150 for determining the existing passenger distribution and passenger situation in the vehicle as a basis for controlling the suspension system 200.

The system I comprises means 140 for determining the passenger distribution in the vehicle as a basis for controlling the suspension system 200. The means 140 for determining the passenger distribution comprise sensors for determining where in the vehicle, e.g. a bus, the passengers are located, and the number of passengers.

According to one variant, the means 140 for determining the passenger distribution comprise sensor elements 142 for sensing where in the vehicle a passenger is sitting, standing, sitting in a wheelchair, lying in a baby carriage or the equivalent, which sensor elements can include pressure sensors. According to one variant, the means 140 for determining the passenger distribution comprise means 142 for determining the passenger population, i.e. the number of passengers in the vehicle. According to one variant, the means 142 for determining the passenger population include a boarding/unboarding sensor for determining the number of passengers who board and unboard the vehicle.

According to one variant, the means 142 for determining the passenger population include a ticket-registering sensor for registering passengers who board the vehicle.

The system I comprises means 150 for determining the existing passenger situation in the vehicle as a basis for controlling the suspension system 200. The means 150 for determining the passenger situation in the vehicle can include any arbitrary suitable sensing elements.

According to one variant, the means 150 for determining the passenger situation in the vehicle include sensor elements 152 for sensing whether a passenger is standing, sitting, sitting in a wheelchair, lying in a baby carriage or the equivalent, which sensor elements can include pressure sensors. According to one variant, the means 150 for determining the passenger situation in the vehicle include sensor elements 154 for sensing any movements by the passengers, e.g. passengers who fall down because of how the vehicle is being driven. Sensor elements for sensing any movements by the passengers can include cameras, such as stereo cameras, laser scanners or the equivalent. Information from one or more of said types of sensor elements provides a accurate representation of where each passenger is located in the vehicle, their height/height of head over the floor, sitting/standing/wheelchair and its orientation, baby carriage and its orientation, and so on. The system I comprises means 160 for determining an anticipated passenger distribution and passenger situation in the vehicle using a model for the behavior of a given passenger population as a basis for controlling the suspension system 200. According to one variant, said model contains input data from a ticket- registering sensor for registering passengers who board the vehicle.

According to one variant, said model contains input data from a boarding/unboarding sensor for determining the number of passengers who board and unboard the vehicle.

According to one variant, the model contains information concerning the number of seats, places to stand and cultural habits, and is configured so as to calculate a probable distribution of the passengers in the vehicle compartment. The system I comprises means 170 for controlling the suspension system 200 while taking into account a passenger perspective that includes taking considerations of passenger comfort into account.

The means 170 for controlling the suspension system comprise means 172 for controlling the suspension of the suspension system 200. The means 170 for controlling the suspension system 200 comprise means 174 for controlling the damping of the suspension system 200.

The system I comprises means 176 for controlling the suspension system to achieve a given inclination of the vehicle to achieve a sloping effect in connection with direction change in the form of cornering. The means 170 for controlling the suspension system 200 consequently comprise means 176 for achieving a given inclination of the vehicle to achieve a sloping effect in connection with direction change in the form of cornering. The means 176 for achieving a given inclination comprise means for lowering one side and/or lowering the opposite other side of the vehicle. According to one variant, the means for raising and/or lowering comprise air suspension elements which, according to one variant, consist of bellows units or comprise bellows units in the air suspension system. According to one variant, the means for raising and/or lowering include electric motors, which, according to one variant, consist of linear motors.

The system I comprises means 178 for controlling the suspension system so as to achieve a given inclination of the vehicle to achieve a reduction in the effect of acceleration in the vertical direction in connection with direction change in the form of hill-cresting/bump absorption. The means 170 for controlling the suspension system 200 consequently comprise means 178 for controlling the suspension system so as to achieve a given inclination of the vehicle to achieve a reduction in the effect of acceleration in the vertical direction in connection with direction change in the form of hill-cresting/bump absorption. The means 178 for achieving a given inclination comprise means for raising the vehicle front and/or lowering the vehicle rear, and vice versa. According to one variant, the means for raising and/or lowering comprise air suspension elements, which, according to one variant consist of bellows units or comprise bellow units in the air suspension system. According to one variant, the means for raising and/or lowering include electric motors which, according to one variant, consist of linear motors.

The electronic control unit 100 is signal-connected to the means 1 10 for determining direction changes of the vehicle via a link 1 1 . The electronic control unit 100 is arranged so as to receive, via the link 1 1 , a signal from the means 1 10 for determining direction changes of the vehicle representing direction change data including lateral acceleration data and/or rotation data for the vehicle.

The electronic control unit 100 is signal-connected to the means 120 for determining velocity changes of the vehicle via a link 12. The electronic control unit 100 is arranged so as to receive, via the link 12, a signal from the means 120 for determining velocity changes of the vehicle representing velocity change data including acceleration data and/or retardation data. The electronic control unit 100 is signal-connected to the means 130 for determining the velocity of the vehicle via a link 13. The electronic control unit 100 is arranged so as to receive, via the link 13, a signal from the means 130 for determining the velocity of the vehicle representing velocity data for the vehicle velocity.

The electronic control unit 100 is signal-connected to the means 140 for determining the passenger distribution via a link 14. The electronic control unit 100 is arranged so as to receive, via the link 14, a signal from the means 140 for determining the passenger distribution representing passenger distribution data including the orientation of the passengers such as passengers who are sitting, standing, sitting in a wheelchair, lying in a baby carriage or the equivalent, movements of the passengers, and passenger population.

The electronic control unit 100 is signal-connected to the means 150 for determining the passenger situation via a link 15. The electronic control unit 100 is arranged so as to receive, via the link 15, a signal from the means 150 for determining the passenger situation representing passenger situation data including the orientation of passengers, such as passengers who are standing, sitting, sitting in a wheelchair, lying in a baby carriage or the equivalent, and movements of passengers.

The electronic control unit 100 is signal-connected to the means 160 for determining an anticipated passenger distribution and passenger situation in the vehicle using a model for the behavior of a given passenger population via a link 16. The electronic control unit 100 is arranged so as to receive, via the link 16, a signal from the means 160 for determining an anticipated passenger distribution and passenger situation in the vehicle using a model for the behavior of a given passenger population representing modeling data for an anticipated passenger distribution and passenger situation in the vehicle. The electronic control unit 100 is signal-connected to the means 170 for controlling the suspension system while taking into account a passenger perspective that includes taking considerations of passenger comfort into account via a link 17. The electronic control unit 100 is arranged so as to receive, via the link 17, a signal from the means 170 representing suspension control data wherein the control includes controlling the suspension/damping of the suspension system and vehicle-side raising/lowering of the suspension system while taking into account a passenger perspective that includes taking considerations of passenger comfort into account. The suspension system 200 is signal-connected to the means 170 for controlling the suspension system while taking into account a passenger perspective that includes taking considerations of passenger comfort into account via a link 20. The suspension system 200 is arranged so as to receive, via the link 20, a signal from the means 170 representing suspension control data for controlling the suspension system while taking into account a passenger perspective that includes taking considerations of passenger comfort into account. Said suspension control data includes suspension adjustment data from the means 172 for adjusting the suspension and/or damping adjustment data from the means 174 for adjusting the damping and/or level adjustment data from the means 176 for achieving a given inclination in the lateral direction of the vehicle to achieve a sloping effect in connection with direction change in the form of cornering and/or level adjustment data from the means 178 for achieving a given inclination in the longitudinal direction of the vehicle so that the vehicle is raised at the rear and/or lowered at the front or vice versa so as to achieve an acceleration reduction in the vertical direction.

The electronic control unit 100 is arranged so as to process said direction change data the means 1 10 for determining direction changes of the vehicle, said velocity change data from the means 120 for determining velocity changes of the vehicle, said velocity data from the means 130 for determining the velocity of the vehicle, and said passenger distribution and passenger situation data from the means 140 for determining the passenger distribution and the means 150 for determining the passenger situation as a basis for controlling the suspension system. The electronic control unit 100 is arranged so as to process said data for modeling data for an anticipated passenger distribution and passenger situation as a basis for controlling the suspension system.

The electronic control unit 100 is arranged so as to process said data and, based on said data, send a signal representing suspension control data to the means 170 for controlling the suspension system 200 while taking into account a passenger perspective that includes taking considerations of passenger comfort into account, including controlling the suspension/damping of the suspension system and raising/lowering the suspension system. Fig. 3 schematically illustrates a block diagram of a method for controlling the suspension system of a vehicle according to one embodiment of the present invention.

According to one embodiment, the method for controlling the suspension system of a vehicle comprises a first step S1 . In this step the suspension system is controlled while taking into account a passenger perspective that includes taking considerations of passenger comfort into account.

A diagram of an embodiment of a device 500 is shown with reference to Fig. 4. The control unit 100 described with reference to Fig. 2 can, in one embodiment, comprise the device 500. The device 500 comprises a non- volatile memory 520, a data-processing unit 510 and a read/write memory 550. The non-volatile memory 520 has a first memory part 530 in which a computer program, such as an operating system, is stored for controlling the function of the device 500. The device 500 further comprises a bus controller, a serial communication port, I/O elements, an A/D converter, a time and date input and transfer unit, an event counter and an interrupt controller (not shown). The non-volatile memory 520 also has a second memory part.

A computer P program is provided that contains routines for controlling the suspension system of a vehicle according to the innovative method. The program P contains routines for controlling the suspension system while taking into account a passenger perspective that includes taking considerations of passenger comfort into account. The program p can be stored in executable form or in compressed form in a memory 560 and/or in a read/write memory 550. When it is stated that the data-processing unit 510 performs a given function, it is to be understood that the data-processing unit 510 executes a given part of the program that is stored in the memory 560, or a given part of the program that is stored in the read/write memory 550.

The data-processing device 510 can communicate with a data port 599 via a data bus 515. The non-volatile memory 520 is intended for communication with the data-processing unit 510 via a data bus 512. The separate memory 560 is intended to communicate with the data-processing unit 510 via a data bus 51 1 . The read/write memory 550 is arranged so as to communicate with the data-processing unit 510 via a data bus 514. For example, the links connected to the control unit 100 can be connected to the data port 599.

Once data are received at the data port 599, they are stored temporarily in the second memory part 540. Once received input data have been temporarily stored, the data-processing unit 510 is arranged so as to execute code in a manner as described above. The signals received at the data port 599 can be used by the device 500 for controlling the suspension system while taking into account a passenger perspective that includes taking considerations of passenger comfort into account.

Parts of the methods described herein can be performed by the device 500 with the help of the data-processing unit 510 that runs the program stored in the memory 560 or the read/write memory 550. When the device 500 runs the program, the methods described herein are executed.

The above description of the preferred embodiments of the present invention has been provided for illustrative and descriptive purposes. It is not intended to be exhaustive, or to limit the invention to the described variants. Many modifications and variations will obviously be apparent to one skilled in the art. The embodiments have been chosen and described in order to best clarify the principles of the invention and its practical applications, and to thus enable one skilled in the art to understand the invention in various embodiments and with the various modifications that are suitable for the intended use.