Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
  • B60T8/17—Using electrical or electronic regulation means to control braking
  • B60T8/1755—Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D11/00—Steering non-deflectable wheels; Steering endless tracks or the like
  • B62D11/02—Steering non-deflectable wheels; Steering endless tracks or the like by differentially driving ground-engaging elements on opposite vehicle sides
  • B62D11/06—Steering non-deflectable wheels; Steering endless tracks or the like by differentially driving ground-engaging elements on opposite vehicle sides by means of a single main power source
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D37/00—Stabilising vehicle bodies without controlling suspension arrangements
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits
  • B62D6/002—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits computing target steering angles for front or rear wheels
  • B62D6/003—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits computing target steering angles for front or rear wheels in order to control vehicle yaw movement, i.e. around a vertical axis
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D9/00—Steering deflectable wheels not otherwise provided for
  • B62D9/002—Steering deflectable wheels not otherwise provided for combined with means for differentially distributing power on the deflectable wheels during cornering
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T2201/00—Particular use of vehicle brake systems; Special systems using also the brakes; Special software modules within the brake system controller
  • B60T2201/12—Pre-actuation of braking systems without significant braking effect; Optimizing brake performance by reduction of play between brake pads and brake disc
  • B60T2201/122—Pre-actuation in case of ESP control
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T2260/00—Interaction of vehicle brake system with other systems
  • B60T2260/02—Active Steering, Steer-by-Wire

Definitions

• the invention relates to a method for guiding a multi-lane vehicle on a curved path, which is specified by the vehicle driver via a predetermined steering angle or the like, wherein a curved path signal representing this desired curved path is given to a person in a form suitably revised by an electronic control unit the actuator influencing the yaw movement of the vehicle is conducted.
• the invention primarily relates to a method for guiding a multi-lane vehicle on a curved path, which is specified by the vehicle driver via a predetermined steering angle or the like, a curved path signal representing this desired curved path being suitably revised in an electronic control unit Form is directed to a steering actuator influencing the steering angle of at least one steerable vehicle wheel.
• So-called active steering systems for motor vehicles which are able to actively and additionally to the steering angle specified by the driver via the steering wheel (or generally a so-called steering handle), are in development or in part already in series production -Wheels (these are usually the front wheels), which creates an additional lateral force on the vehicle front axle and consequently a desired yaw moment can be generated. Such systems are thus able to significantly influence the driving dynamics of a motor vehicle.
• Such active steering systems can be, for example, a so-called steer-by-wire system, or a superimposed steering system which is also known to the person skilled in the art and which mechanically adds an additional steering angle to the so-called default steering angle of the driver that a resulting total steering angle is set on the steerable vehicle wheel.
• Measures or methods with which the dynamic steering response behavior can be improved are particularly desirable in that a basically existing phase delay in the transmission between the driver's steering specification (for example on the steering wheel) and the resulting yaw reaction of the vehicle can be reduced.
• lead steering which is mentioned, for example, in DE 197 51 125 A1, mentioned at the beginning, and which is a controlled steering intervention in which an additional steering angle generated is proportional to the steering wheel and rotational speed , that is to say the driver's stipulated steering angle at different times.
• the measured default steering angle can be filtered by a simple PD lead and additionally set on the steerable wheels according to a predetermined steering ratio.
• the provision of the steering wheel angle by the PD lead element causes a smaller phase delay in the transmission between the steering specification on the steering wheel and the yaw reaction of the vehicle and thus ensures a faster response of the vehicle movement to a steering specification of the driver.
• Another possible method for improving the steering response behavior on motor vehicles is a so-called model-based pre-control of the yaw rate.
• a so-called reference yaw rate is first determined and from this an appropriate steering angle for the steerable wheels is determined by means of an inverse vehicle model and then suitably adjusted on these. If there is a good match between the underlying vehicle model and the real vehicle, the steering angle calculated in this way ensures the desired yaw movement of the vehicle, ie the actual yaw rate corresponds to the so-called reference yaw rate.
• the transmission between the steering specification on the steering wheel and the yaw response of the vehicle can be specifically adjusted in this way and, in particular, an improvement in the steering response behavior can be achieved.
• a control deviation is derived from the discernible difference between the actual value of the yaw rate and a suitably determined yaw rate setpoint, which can then be supplied in the sense of minimization, for example, to two controllers working independently of one another, namely a steering controller and a brake controller .
• the actual yaw rate of the vehicle is measured in the latter control method and adapted to a target yaw rate, this target yaw rate both through interventions can be maintained in the vehicle steering system as well as by interventions in the vehicle braking system. This means that additional steering or braking can be used to react to a deviation due to any influences between the curve path actually traveled and the desired curve path.
• the present invention now does not relate to a control method in which a target / actual comparison (for example with regard to the yaw rate) is carried out, but rather relates to a method for pilot control solely from the two basic input variables, namely the so-called "Default steering angle" and the "vehicle speed", it being the object of the present invention to show a method with significantly greater freedom than in the known lead steering.
• a target / actual comparison for example with regard to the yaw rate
• the curve path signal formed from the specified steering angle and the vehicle speed and in particular representing the yaw rate can be used in the sense of a pilot control for the suitable change of the longitudinal force on the wheels of at least one side of the vehicle, so that In addition to or instead of setting a steering angle, a longitudinal force can also be applied to at least one vehicle wheel in order to drive on the desired curved path.
• the curved path signal representing the desired curved path is passed in a form suitably revised by an electronic control unit to a steering actuator influencing the steering angle of at least one steerable vehicle wheel
• this can be done from the default Head angle and the Vehicle speed formed and in particular representing the yaw rate curve signal in the sense of a pre-control not only for the appropriate control of the steering actuator, but also for the suitable change of the longitudinal force on the wheels of at least one side of the vehicle, so that in addition to or instead of the adjustment of a Steering angle can additionally or solely be applied to at least one vehicle wheel with a longitudinal force in order to negotiate the desired curved path.
• Advantageous further developments are the content of the further subclaims.
• Said longitudinal force is preferably generated by applying a braking force to the wheel or wheels of a vehicle side, but it is also possible to have a driving force act on one side or to combine the two longitudinal forces mentioned, so that the wheels on one vehicle side slowed down and accelerated on the other side of the vehicle.
• the application of a longitudinal force is equated with the application of a braking force, i.e. Even if the following only speaks of a braking force with respect to a vehicle wheel, a suitably large driving force can instead be applied to a vehicle wheel on the opposite vehicle side in order to achieve a comparable yaw moment resulting therefrom ,
• a pilot control method according to the preamble of claim 1 is proposed, which enables an improvement in the driving behavior or a yaw movement of the vehicle, preferably by means of integrated or generally combined steering interventions and braking interventions.
• By braking individual wheels in a targeted manner an additional yaw moment can be applied to the vehicle that supports a steering process. In this way, further improvements in the steering response behavior can then be achieved even when the system limits, for example the steering actuator system, are reached.
• the control interventions can be divided as desired between the steering system and the braking system of the vehicle. It can also be provided that only the vehicle brake system is suitably controlled, which enables the vehicle to be steered with pure brake intervention on individual wheels without the steerable vehicle wheels being turned.
• a first yaw moment component can thus be achieved by the steering angle of the steerable vehicle wheels and a second yaw moment component can be generated by applying a longitudinal force in the form of a braking force (and / or a driving force).
• a longitudinal force in the form of a braking force (and / or a driving force).
• These two yaw moment components in total then result in the yaw moment that is required for the successful and agile negotiation of the desired cam track, at least when there are no significant disturbing influences.
• This latter yaw moment which is formed from the sum of the two yaw moment portions, is hereinafter referred to as the actuator yaw moment, which is suitable to apply, and can be used in the sense of a precontrol in the absence of interference, solely from the specified steering angle and the current vehicle.
• Driving speed can be determined.
• the so-called actuator yaw moment to be applied for successfully driving the desired curved path can be determined, for example, or preferably by means of a linear single-track model, the current lateral force of the steerable wheel or wheels resulting from the set steering angle being to be reduced. to be able to take into account the so-called reaction moment of the vehicle.
• the desired yaw rate results from -
• the actuator yaw moment which must now be applied to the vehicle by means of one or more actuators so that it moves at the desired yaw rate.
• this actuator yaw moment according to the invention into a yaw moment component that can be generated by setting a steering angle and a yaw moment component that can be generated by applying a longitudinal force can be freely selected, one of the components also having the value “zero”
• This division into a steering actuator or a braking actuator can, however, also take place in a variable manner depending on boundary conditions.
• the actuation speed of the driver's steering handle ie the steering wheel rotation speed
• the actuation speed of the driver's steering handle can be taken into account here, but there is also a map -controlled division possible, for example, on the basis of the vehicle driving speed, an adjustment limitation of an actuator used, in particular the steering actuator, and the dynamic behavior of the actuator or the respective one can also be taken into account as a boundary condition or influencing variable affected actuators.
• the steering actuator it is still possible to steer the vehicle, solely by braking.
• the yaw moment component generated by the setting of a steering lock angle results from a low-pass filtering of the total actuator yaw moment to be applied for driving on the desired curved path.
• a low-pass filtering results in a particularly agile dynamic behavior, since the “fast” parts from the desired yaw rate are then almost instantaneous acting brake interventions can be implemented, while the "slower" shares are realized via the steering angle of the steerable vehicle wheels.
• the so-called curve path signal representing the desired curve path can also be used instead of the yaw rate as the so-called float angle or the lateral acceleration of the vehicle.
• the float angle ß can now be used in addition to the yaw rate signal ( ⁇ ) or the curve path signal representing the lateral acceleration a y of the vehicle may be predetermined, with the corresponding values being suitably defined. A resulting lateral force is then predetermined, so that the steering angle is determined thereby.
• a steering angle on the steerable vehicle wheels can not only be set manually by the driver of the vehicle, as in conventional steering systems, but not only by means of an actuator.
• this is what So-called curve path signal preferably in the form of the yaw rate, the steering angle of the steerable vehicle wheels (or the steerable vehicle wheel) is predetermined.
• a further yaw moment can be generated via a longitudinal force applied to at least one vehicle wheel, this further yaw moment in the sense a pilot control is derived solely from the default steering angle and the vehicle speed.
• FIG. 1 the so-called actuator yaw moment explained above is subjected to low-pass filtering in order to generate the steering angle by setting it Yaw moment component to be determined, while in Figure 2 the latter yaw moment component is determined by specifying both the yaw rate and the vehicle lateral acceleration.
• the variant according to FIG. 3 is the one with a conventional steering system, the steering angle of the steerable vehicle wheels being set directly in accordance with the specified steering angle of the driver, preferably with direct mechanical transmission, so that in addition to the (for example ) Yaw rate of the steering angle is specified.
• FIGS. 1, 2, 3 represent the calculation processes in a suitable electronic control unit, the following symbols generally representing the following parameters, which are also explained:
• ⁇ LR The so-called default steering angle is referred to as ⁇ LR , ie the driver's wish to steer, which he can set in particular on a steering wheel.
• V Fzg the vehicle speed, that is, the current driving or longitudinal velocity of the vehicle referred.
• a curve path signal representing the desired curve path results from the specified steering angle ⁇ LR and the vehicle speed VFzg.
• ⁇ r e t denotes the quasi-predetermined yaw rate of the vehicle, which results as the so-called curve path signal representing the desired curve path from the predetermined steering angle ⁇ R of the driver and the current driving speed v zg of the vehicle.
• Mr it is a so-called resulting yaw moment that is present
• Reaction torque of the vehicle referred to, which, inter alia,
• ⁇ can be determined from the predetermined yaw rate ⁇ re f in a reaction torque estimator, and this results from a cornering of the vehicle in which the steerable wheels are not turned and in which no additional longitudinal force acts on the wheels, ie that the vehicle. - Wheels should not be braked or accelerated.
• Ma kt denotes the so-called actuator yaw moment, which must be applied to the vehicle by means of suitable actuators so that the yaw rate ⁇ re f acts on the vehicle. It is known that this actuator yaw moment M act, the difference between the resulting yaw moment M res and the reaction torque M rea kt •
• This steering angle ⁇ R ad causes a (first) yaw moment component Makt, i e n ⁇ which is based on the tire behavior and the distance between the vehicle front axle (VA), which carries the steerable vehicle wheels, and the vehicle Center of gravity (SP) is directly related to the steering angle ⁇ wheel .
• yaw moment component M a kt, ienk there is a further (second) yaw moment component M a kt, brakes, which can be generated by applying a longitudinal force, in particular a braking force, to at least one wheel of a vehicle side.
• the actuator yaw moment M act to be applied is now converted into a yaw moment component Ma kt .i e n k that can be generated by a steering angle ⁇ R 3d and a yaw moment component M act that can be generated by applying a longitudinal force in the form of a braking force and / or a driving force , b r e m s quasi divided.
• the two yaw moment components Maktjenk and M a kt together brake the total actuator yaw moment M a w.
• F y . act is the lateral force generated by the steering angle of the steerable vehicle wheels, which is directly related to the steering angle ⁇ Rad via the tire behavior.
• F yr e act is also used to denote the reaction lateral force, which can be determined from a given transverse acceleration a y ⁇ re f by means of a reaction torque / force estimator .
• the actuator yaw moment M a k t which can be determined as described, is now via a filter Low pass filter passed, from which the steering angle ⁇ R a d can be obtained directly.
• This steering lock angle ⁇ R 3d is set by a suitable actuator, wherein this actuator can either be part of a steer-by-wire system or part of a superimposed steering, as was already described at the beginning.
• the yaw moment component M a kt, ienk generated thereby can be determined from this steering angle ⁇ wheel , so that the further yaw moment component Makt to be generated by applying a longitudinal force can be derived directly from this.
• b remse results.
• This is then implemented by means of a suitable actuator, ie the wheel brakes of the vehicle are preferably suitably actuated on one side.
• the lateral force Fy act caused by the steering angle ⁇ Rad be taken into account reaction torque estimator in the said.
• this desired transverse acceleration is now first acceleration a y, r e f determines a resulting lateral force Fy.res corresponding to this, from which the reaction lateral force F y ⁇ reakt determined in the estimator is subtracted in order to obtain a lateral force F y , a kt that can be generated with a suitable steering actuator. From this, not only the required steering angle ⁇ R a d , but also the resulting yaw moment component M a k t , ienk can then be determined in the manner described.
• the embodiment according to FIG. 3 is a vehicle with a conventional steering system, the steering angle ⁇ R3d of the steerable vehicle wheels being set directly in accordance with the driver's specified steering angle ⁇ LR, preferably with direct mechanical transmission with a suitable gear ratio (with “Steering ratio” denotes), so that in addition to the yaw rate ⁇ re f the steering angle ⁇ Rad is predetermined. From this (as in FIG. 1) the resulting yaw moment component M 3k t, ienk can then be determined, which is then the specified one actuator yawing moment M a is kt subtract in order to be obtained by the application of a longitudinal force to be generated yawing moment fraction M act, br s e em.
• the main advantage of the method presented and implemented in all exemplary embodiments is a so-called yaw rate precontrol Integrated or combined steering intervention and braking intervention is that compared to a pilot control with only steering intervention, the steering response behavior can be significantly improved by additional braking intervention on individual wheels.
• Another advantage (at least in the variants according to FIGS. 1, 2) is the possibility of arbitrarily dividing the active control interventions into the steering system and the braking system of the vehicle. This quasi additional degree of freedom makes it possible, for example, to very easily implement a so-called "steer-by-brake functionality", in which a desired yaw movement of the vehicle can be set by pure braking intervention on individual wheels.
• Such a “steer-by-brake functionality" advantageously makes it possible to maintain the steerability of the vehicle, for example in the event of a complete failure of the steering actuator system, although it should also be pointed out that a large number of details also deviate from the above explanations can be without leaving the content of the claims.

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• Engineering & Computer Science (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Physics & Mathematics (AREA)
• Mathematical Physics (AREA)
• Steering Control In Accordance With Driving Conditions (AREA)
• Regulating Braking Force (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Related Child Applications (1)

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Citations (4)

Family Cites Families (14)

• 2002
  • 2002-08-09 DE DE10236734A patent/DE10236734A1/de not_active Withdrawn
• 2003
  • 2003-07-08 JP JP2004531792A patent/JP2005535509A/ja active Pending
  • 2003-07-08 WO PCT/EP2003/007309 patent/WO2004020262A1/de not_active Ceased
  • 2003-07-08 DE DE50308982T patent/DE50308982D1/de not_active Expired - Lifetime
• 2005
  • 2005-02-08 US US11/052,117 patent/US7200479B2/en not_active Expired - Fee Related

Patent Citations (4)

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