Abstract: A method and apparatus to estimate slopes accurately, as well as to eliminate slope estimation errors, taking error generating conditions into account. The slope on which the vehicle is running is estimated from the vehicle speed and the engine rpm value. The result is entered to the slope estimation unit through a low pass filter, then to the navigation unit. A noise eliminator is provided to the output of the slope estimation unit so that noises can be eliminated, for example, during gear-shifting or for a certain time after the gear shifting is completed by obtaining the "gear shifting" information from the automatic transmission control. The preceding estimated slope value is held during the noise elimination period.

Abstract: In a vehicle behavior control system, a failure of a wheel speed sensor is detected by a wheel speed sensor failure detecting device based on the mutual comparison of wheel speeds detected by wheel speed sensors, respectively. When the failure of the wheel speed sensor is detected, a preselected fail-safe operation is carried out by a fail-safe device. A fail-safe operation prohibiting signal is output only for a predetermined time from the establishment of a state in which the operation of a parking brake is detected by a parking brake operation detecting device and a during-traveling signal is output from a during-traveling signal generated device. When the fail-safe operation prohibiting signal is output, the fail-safe operation by the fail-safe device is prohibited by a fail-safe operation prohibiting device.

Abstract: An electronic controller includes an internal power stabilizing circuit which supplies stabilized power to drive circuits and a fail-safe relay drive circuit all built within the controller, a monitoring unit which monitors the operational states of the circuits in the controller based on the state of power output of the power stabilizing circuit, and a drive unit which drives the fail-safe relay drive circuit in response to the detection by the monitoring unit of a predetermined output state of the power stabilizing circuit indicative of the occurrence of abnormality in at least one of the circuits including the drive circuits within the controller.

Abstract: The present invention describes a process for a vehicle including an electronic control system, which processes input signals representative of the rotational behavior of the individual wheels, and wherein the differences of the tire tread circumferences of the individual wheels are determined by way of short-time and long-time correction factors. The long-time correction factors LZ.sub.n. are determined from the differences D.sub.R1 between the short-time correction factors KZ.sub.R1 and the long-time correction factors LZ.sub.R1 of the respective wheel by averaging LM.sub.r1 the differences during a predetermined time interval and by evaluating and weighting the average value. For the quick identification of an emergency wheel, every time the vehicle engine is started, the long-time factor LZ.sub.R1 is equalled once to the short-time factor KZ.sub.

Abstract: A circuit arrangement for safety-critical control systems, for example, for the control of anti-lock brake systems, is based on an at least partly redundant processing of input data which are taken into account for generating control signals. The control system is disconnected upon non-correlation of the signals. A microprocessor system is provided for data processing and includes two or more central processor units permitting parallel processing of the input data. The output data of the CPUs are checked for correlation. Each write/read memory of the microprocessor system has a generator to generate a test information. The write/read memories and the read-only memories are extended by memory spaces for the test information. In every writing or reading access to the memories, the contents of the memory space is tested with the associated test information for correlation, and an error identification signal is generated in the absence of correlation or plausibility.

Abstract: A circuit arrangement for conditioning and evaluating the signals emanating from wheel sensors in a first stage determines the sensor(s) supplying the highest useful signal at very low wheel speeds. The signal from the most sensitive sensor is delivered when the wheel speed is below the predetermined speed threshold. Above the speed threshold, however, the signal from a sensor arranged on a driven vehicle wheel is used as the vehicle speed signal. The circuit is especially suitable for anti-lock and traction slip control systems which supply speed signals which can also be evaluated for other vehicle control or regulating systems.

Abstract: A control system for motor vehicles in which the errors in wheel velocities created by tolerances between the tires are compensated.

Abstract: A method of an accurate detection of a spinning vehicle wheel. Observed wheel speeds are derived by measuring the speed of each wheel and the slowest speed is set as the slowest observed wheel speed. A maximum probable wheel speed is derived by multiplying the slowest observed wheel speed by the ratio of the maximum wheel speed to the slowest wheel speed for a given minimum turning radius. The maximum probable wheel speed is compared with an observed wheel speed and if the observed wheel speed is greater, the wheel is deemed to be spinning.

Abstract: A sensor failure and detection apparatus and method for use in a redundant sensor system are disclosed. A control circuit disconnects reference power supplied to a sensor and then monitors the voltage decay output by the sensor. The monitored rate of voltage decay of the sensor is compared to the expected natural voltage decay of the sensor to detect failures caused by short or open circuits. An error counter keeps track of the number of failures. After a threshold number of times in which the monitored voltage decay does not compare to a predicted rate of decay, power to the sensor is removed and the sensor is isolated from the system.