Abstract: An electrohydraulic brake system where brake pressure is controlled by the combined action of an apply valve and a dump valve by the implementation of a method of controlling the voltage applied to the apply and dump valve. The EHB pressure control system receives a desired wheel pressure command and, with a caliper pressure feedback signal, implements an algorithm to compute one voltage command for the apply valve and another for the dump valve, corresponding to a requested flow from the hydraulics. The voltage command drives current control electronics. The electronics in turn power the solenoids of the proportional apply and dump poppet valves to control flow in or out of the brakes and modulate wheel pressure as required. Use of the algorithm to control the electromagnetic poppet valves achieves the commanded pressure at a vehicle's brakes reliably and with good control in all states of flow through the valve.

Abstract: A system for real-time signal processing for vehicle monitoring, including a first device disposed in a tire of a vehicle and producing a signal that is a function of a tire contact time period, during which a point at the tire circumference stays in contact with the ground, and a second device operative to repetitively perform a first task of processing the signal to calculate the tire contact time period at a first predetermined rate, and to repetitively perform a second task of calculating a tire load based at least in part upon the calculated tire contact time period at a second predetermined rate, wherein said second predetermined rate is less than said first predetermined rate.

Abstract: A method of controlling pressure in a fluid system having a source of pressurized fluid for which a maximum desired fluid pressure value has been determined, a hydraulic load, an apply valve controlling pressurized fluid flow between the source and the load, and a release valve permitting fluid flow from the load to a low pressure reservoir. Pressure is controlled at the hydraulic load by at least one of closing the release valve and opening the apply valve to increase pressure at the hydraulic load, and by at least one of closing the apply valve and opening the release valve to reduce pressure at the hydraulic load.

Abstract: A system for real-time signal processing for vehicle monitoring, including a first device disposed in a tire of a vehicle and producing a signal that is a function of a tire contact time period, during which a point at the tire circumference stays in contact with the ground, and a second device operative to repetitively perform a first task of processing the signal to calculate the tire contact time period at a first predetermined rate, and to repetitively perform a second task of calculating a tire load based at least in part upon the calculated tire contact time period at a second predetermined rate, wherein said second predetermined rate is less than said first predetermined rate.

Abstract: A method of boundary auto-calibration for proportional poppet valve pressure control estimates the boundary deviation of the valve. A pressure command signal is detected and a pressure command derivative over time is obtained. Which closing boundary should be updated is decided based on the sign of the pressure command derivative. A pressure error is obtained by subtracting an actual wheel brake pressure from its pressure command. Then, a modified pressure error is calculated, and a pressure command signal is evaluated to determine whether a braking maneuver is gentle. Next, the modified pressure error is implemented in the estimation. Finally, a boundary table is updated using the resultant boundary deviation estimate. An alternate embodiment implements a fast boundary auto-calibration scheme including a quasi-closed-loop pressure control system using one cycle of pressure upward sweep and pressure downward sweep to cover the entire operating range of pressures for the valves.

Abstract: An electrohydraulic brake system where brake pressure is controlled by the combined action of an apply valve and a dump valve by the implementation of a method of controlling the voltage applied to the apply and dump valve. The EHB pressure control system receives a desired wheel pressure command and, with a caliper pressure feedback signal, implements an algorithm to compute one voltage command for the apply valve and another for the dump valve, corresponding to a requested flow from the hydraulics. The voltage command drives current control electronics. The electronics in turn power the solenoids of the proportional apply and dump poppet valves to control flow in or out of the brakes and modulate wheel pressure as required. Use of the algorithm to control the electromagnetic poppet valves achieves the commanded pressure at a vehicle's brakes reliably and with good control in all states of flow through the valve.

Abstract: A method of boundary self-adaptation for proportional poppet valve pressure control comprises implementing an estimator to estimate a boundary deviation of the valve. Then, a pressure command signal is detected. Next, a pressure command derivative over time is obtained. Then, determining which closing boundary should be updated is decided based on the sign of the pressure command derivative. Next, a pressure error is obtained by subtracting an actual wheel brake pressure from its pressure command. Then a modified pressure error is calculated. Next, a pressure command signal is evaluated to determine whether a braking maneuver is gentle. Next, the modified pressure error is implemented in the estimation. Finally, a boundary table is updated using the resultant boundary deviation estimate.

Abstract: An electrohydraulic brake system where brake pressure is controlled by the combined action of an apply valve and a dump valve by the implementation of a method of controlling the voltage applied to the apply and dump valve. The EHB pressure control system receives a desired wheel pressure command and, with a caliper pressure feedback signal, implements an algorithm to compute one voltage command for the apply valve and another for the dump valve. The solenoids of the proportional apply and dump poppet valves are operated to control flow in or out of the brakes and modulate wheel pressure as required. The algorithm is used to control the electromagnetic poppet valves in all states of flow through the valve. The algorithm is a function of the existing pressure within the system and whether there is bulk or leakage flow through the valves.