A surgical instrument (e.g., endocutter, grasper, cutter, staplers, clip applier, access device, drug / gene therapy delivery device, and energy device using ultrasound, RF, laser, etc.) may benefit from having a plurality of hydraulically actuated subsystems (e.g., severing, stapling, articulation, locking / unlocking, lockout enabling / disabling, grasping, etc.) supplied with hydraulic power from a trigger actuated rotary pump (e.g., lobe pump, rotary gear pump, internal rotating gear pump, flexible vane rotor pump, rotary vane pump). Thereby, an available amount of mechanical advantage available at a firing trigger may be optimally distributed to various end effector components, perhaps sequenced by an electroactive polymer or piezoelelectrically actuated function switch block.