Abstract: A control system for a stabilizing apparatus for a rail vehicle body, which is tiltable on a bogey by means of jacks, comprises a lateral accelerometer and an angular accelerometer mounted on the vehicle body, two servo-mechanisms respectively responsive to operation of the lateral and angular accelerometers, and a control valve for the tilting jacks, the control valve being coupled to output members of the servo-mechanisms so that tilting movement of the vehicle body in response to operation of the lateral accelerometer is sensed by the angular accelerometer so as to urge the control valve in a direction to oppose the aforesaid tilting movement.

Abstract: A vehicle suspension system has a hydro-pneumatic suspension unit for each wheel, transducers for sensing the pressures in the respective suspension units, transducers for sensing the velocities, relative to the vehicle body, of the respective wheel axes, damping control valves for the respective suspension units and control means, responsive to signals from the pressure and velocity transducers, for varying the damping effects of the control valves.

Abstract: An electrically-controlled damping device for use in a vehicle suspension includes a cylinder, a piston slidable in the cylinder and a damping control valve controlling the interconnection of the two ends of the cylinder. The valve is servo-operated by means of an electrical pilot valve and hydraulic working fluid for the servo-system is supplied from the cylinder itself through the intermediary of a bridge rectifier arrangement of one-way valves.

Abstract: A wheel suspension arrangement for a wheel carrier including a suspension spring and a damper has a valve, controlling the damper. A displacement transducer detects the position of the wheel carrier relative to the vehicle body and provides an input to a function generator which produces an output corresponding to the required value of the acceleration of the wheel carrier. A comparator compares the actual acceleration with the desired acceleration and controls the valve accordingly.

Abstract: A hydraulic actuating arrangement for an aircraft control surface has a control circuit, responsive to a position selection input signal, for providing six nominally identical output control signals. Six pilot valves respectively responsive to the control signals provide six servo pressure signals to respective ones of six intermediate actuators. The intermediate actuators are resiliently coupled to each of two main hydraulic control valves. Three of the intermediate actuators and one of the main control valves are supplied from a first hydraulic pressure source, the remaining three intermediate actuators and the remaining main control valve being supplied from a second hydraulic pressure source. An output actuator is responsive to output pressures from either of the main control valves.