Abstract: At low speeds, an antiskid/autobrake control system applies a brake release current to the antiskid valves of the brake system associated with selected wheels of an airplane to prevent brake shudder caused by gear walk. The control system obtains a measured wheelspeed value from each of the selected wheels and calculates a reference wheelspeed based the measured wheelspeed. Tests are made to determine if the reference wheelspeed is below some predetermined magnitude, e.g., 15 knots, and if the airplane ground speed is below some predetermined magnitude, e.g., 50 knots. If the tests are passed, the value of a low-speed brake release current to be applied to the antiskid valves of the airplane's brake system is determined. In order to prevent an abrupt change in braking, the low-speed brake release value ramps off as the airplane slows to a stop. Releasing some of the brakes results in the pilot increasing pressure on the remaining brakes, thereby eliminating brake shudder due to gear walk.

Abstract: A braking device of diagonal type having two sub-systems each including a front wheel brake cylinder and a rear wheel brake cylinder which are connected to master cylinder through respective front and rear passages in which are first and second solenoid-operated valves are disposed. The rear passage is connected to a portion of the front passage between the first valve and the front wheel brake cylinder, and a third solenoid-operated valve is disposed in a reservoir passage connecting the rear passage to a reservoir connected to a pump. A controller for controlling the valves and the pump includes a device for alternately opening and closing the third valve in a predetermined switching pattern while the second valve is held open or is alternately opened and closed, whereby the rate of change of the braking pressure in each wheel brake cylinder can be controlled as desired depending upon the switching pattern of the third valve.

Abstract: A method and device for driving an electromagnetic valve, in particular an electromagnetic valve of a braking system having antilock protection and/or a traction control system. When switched over into the position that permits the passage of flow, the valve is so driven that, in a first phase for a specifiable time (DT), the current falls off in accordance with a first function and remains nearly constant over time in a second phase.