Abstract:
In a motor car or other wheeled vehicle provided with electronically controlled wheel brakes, the lag or slip of the individual wheels is determined to render possible a control such that locking and skidding of the wheels is prevented. During braking, the brake of one wheel of the vehicle is intermittently released so that the wheel is intermittently free-running without slip. The speed of the vehicle is continuously measured by an accelerometer of simple type and an integrator integrating the accelerometer output. The true speed of the vehicle is intermittently measured by a speed transducer associated with said wheel and having an output representative of true speed during the free-running interval of the wheel. The approximate continuous speed value is recurrently updated by the intermittent true speed signal so that the integrator output is proportional to the ratio of the speed of the vehicle to that of the wheel and is a quantity to control the brake of the wheel in dependence of the slip of the wheel by comparison with a permissible or tolerable slip limit value.
Abstract:
In a brake control system of wheeled vehicles, particularly of motor cars, an arrangement measures the vehicle speed by means of an accelerometer of simple type to produce a signal representing the speed of a braked individual wheel relative to the vehicle speed. The wheel is intermittently braked to be temporarily freerunning without slip so that the true vehicle speed is repeatedly measured by an inductive or other speed transmitter. Furthermore, the vehicle speed is continuously, though inaccurately, measured by integration of the output of an accelerometer of a simple cheap type. This integrated output is repeatedly corrected by being updated with the true vehicle speed intermittently measured by the speed transmitter when the wheel is free-running. During those periods during which the wheel is braked and may be lagging (slipping), the measured wheel speed differs from the updated speed represented by the integrated and updated accelerometer output. By comparison of these two speed values, an electrical signal representing the slip is produced and may be used for temporarily releasing the brake means of the vehicle when slip occurs or at least when the ratio of slip to speed passes a predetermined limit value. Any accelerometer output representing a negative retardation, i.e. positive acceleration, is suppressed.
Abstract:
This invention is related to a safety checking device for an electronic braking system used primarily in wheeled vehicles and which indicates a malfunction of the system before the braking system is applied. The safety device introduces a signal to an electronic unit in the braking system; if there is a failure thereof, a warning circuit is triggered to give a proper alarm to the vehicle operator. The safety device is also designed so that it does not operate during application of the braking system.
Abstract:
An arrangement for controlling and monitoring electronic control systems for the brakes of wheeled vehicles (motor cars) includes speed sensors, one for each controlled wheel, the output of each sensor being applied to a detector for detecting relative changes in speed of the wheel. The detector controls a number of solenoid valves to regulate the brake pressures for the individual wheels such that locking and skidding of any wheel is prevented. A delay circuit samples or senses the signal occurring in the output of the detector, which output is supplied to a driving stage driving the associated solenoid valve. The output of the delay circuit activates a comparator when the output of the detector results in a reduction or release of the braking power of one or more of the wheels of the vehicle during a period exceeding a normal transient period of the regulating system. When the comparator is activated, it energizes a switch provided for the associated driving stage such that the polarity of the output of this stage changes and results in switching on again the solenoid valve to open a braking-fluid connection to the normal, ordinary braking system of the vehicle. When the comparator is energized, a buzzer or signal lamp is also energized.