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
  • B60T8/173—Eliminating or reducing the effect of unwanted signals, e.g. due to vibrations or electrical noise
• • 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
  • B60T8/172—Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters
• • 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
  • B60T8/176—Brake regulation specially adapted to prevent excessive wheel slip during vehicle deceleration, e.g. ABS
  • B60T8/1761—Brake regulation specially adapted to prevent excessive wheel slip during vehicle deceleration, e.g. ABS responsive to wheel or brake dynamics, e.g. wheel slip, wheel acceleration or rate of change of brake fluid pressure
  • B60T8/17616—Microprocessor-based systems
• • 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
  • B60T8/176—Brake regulation specially adapted to prevent excessive wheel slip during vehicle deceleration, e.g. ABS
  • B60T8/1763—Brake regulation specially adapted to prevent excessive wheel slip during vehicle deceleration, e.g. ABS responsive to the coefficient of friction between the wheels and the ground surface
  • B60T8/17636—Microprocessor-based systems

Definitions

• the invention relates to a method according to the preamble of claim 1.
• Time t a_mitt (delta__t) average vehicle deceleration during the time interval
• the current vehicle speed v_vehicle is also after Equation (1) is known at all times.
• p_mitt_rad (i, delta_t) average brake pressure of the i-th
• K proportionality constant, in which vehicle-specific parameters are taken into account (essentially the diameter of the wheels and brake discs and the vehicle mass)
• K is a constant that is set according to the concept presented here for a specific vehicle type.
• K can vary greatly due to different loading and braking conditions, all variables derived from (2) may only serve as a rough reference. The summation in equation (2) is permissible if it is assumed that the vehicle weight is distributed on the same side and that for each side it applies that the respective front wheel has the same coefficient of adhesion to the road surface as the associated rear wheel on average over time:
• equation (2) permits an approximate calculation of the vehicle speed, called “vehicle reference speed", which forms the basis for the analog ABS control concept described here.
• vehicle reference speed forms the basis for the analog ABS control concept described here.
• the brake pressure transducers normally required for this would have to be designed for relatively high pressures (up to 200 bar) and measure as quickly and precisely as possible.
• brake pressure transmitters of this type cannot be used in a standard ABS system. The system presented here therefore assumes that a pressure actuator
• Plunger system in which there is a clear connection between the control of the pressure piston resulting from the control (hereinafter referred to as "manipulated variable U") and the pressure present in the system.
• v_ideal means ideal wheel circumference speed v_hus vehicle reference speed slip ideal ideal slip value based on the vehicle reference speed (this need not necessarily be the true vehicle speed, since calculation errors are possible according to 2.1).
• Equation (5) is based on the following slip definition:
• Wheel and road surface M_Brems braking torque due to brake pressure
• K rolling friction constant
• ts. 0 means that, in view of a desired vehicle deceleration, an angular deceleration of the wheel is naturally also sought. However, this should be small in terms of amount ( ⁇ 1.6 ⁇ _ 1.6g / r), so that it is ensured that there is no drop in wheel speed caused by braking.
• the ideal slip according to equation (8) When finding the ideal slip according to equation (8), one takes advantage of the fact that the / ⁇ slip characteristic curve generally has a maximum which one should ideally "start” with the slip setting of the wheel. If there is no j-maximum in the stable slip area (this is the case, for example, on snow and gravel), the minimum slip is set for which the ju values do not yet decrease significantly. The following shows how the ideal slip according to (8) can be found.
• a realization of the desired slip control can be realized with the aid of a plunger pressure odulator because the manipulated variable U (see 2.1) the brake pressure set in each case is known, so that the condition (9) can be met, which states that the Torque balance for the maximum braking torque (ie for the maximum braking pressure) is sought.
• S_START is preset and the associated brake pressure P is temporarily stored as P_ALT.
• the slip is then increased by an amount S_DELTA and the stable P value compared to P_ALT. If P »P_ALT applies, then that was
• the slip control always allows the ideal slip to be found between the tire and the road. In order to be able to set this quickly in terms of control technology, the analog ABS control described below is required. 2.3 Analog ABS control
• analog control is not to be understood here as a control with analog circuit components, but the mechanisms described below can also be realized with conventional ⁇ -controllers. Rather, what is meant here is that the conventional ABS strategy is not used, according to which the pressure is gradually reduced and built up via magnetic valves in order to keep the wheel acceleration in a desired band.
• the concept presented here provides for setting analog (non-quantized) pressure values, which are calculated from the respectively existing control difference between the ideal speed and the actual wheel speed.
• T_a i T_v p (i) p ahrer - K * [x (i) + - * ⁇ x (i) + - * (x (i) -x (i-l))]
• K_R control gain
• T_n readjustment time of the integral component
• T_v retention time of the differential component
• Fig. 4 shows the functional structure of such a control loop.
• the signal U serves as a direct manipulated variable, which is also used to calculate the vehicle reference speed and as a pressure-proportional decision variable for the slip control.

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• Engineering & Computer Science (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Regulating Braking Force (AREA)

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Cited By (2)

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Citations (6)

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• 1989
  • 1989-05-20 DE DE19893916513 patent/DE3916513A1/de active Granted
• 1990
  • 1990-05-14 WO PCT/DE1990/000355 patent/WO1990014255A1/de not_active Ceased

Patent Citations (6)

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