Mechanically redundant actuator assembly

摘要

In a mechanically redundant actuator system, the actuator has a structurally redundant members for attaching it between a stationary anchor point to a movable control surface. Specifically the actuator consists of a cylinder body, a double action piston with a piston rod attached to the control surface at one end and a swivel bar at the other end. Single or multiple tie rods are attached between the swivel bar and the movable control surface. Each tie rod can withstand one half the load of the piston rod. Also, trunnion links attach the cylinder body to the structure. Each trunnion links can withstand the full limit load with or without any load factors. The trunnion fittings can be any configuration that provides a structural reaction, and provides a dual load path and freedom of movement in at least two axes. At least two of these actuator units are required per surface. Also, a dual tandem control valve with a hydraulic compensator for each actuator is required. With this arrangement, the failure modes allowable are latent mechanical failure of the mechanical links in addition to the total failure of any actuator in combination with any inoperative condition in the hydraulic power system. Various arrangements of the basic system are contemplated within the scope of this invention and include the tail end of each actuator's piston rod connected to a swivel beam. This beam is also connected to the control surface with one or more connecting rods. Each actuator is supported by a trunnion, whether directly connected to the cylinder or otherwise and the trunnion must be able to react to full surface hinge moments.