A surgical instrument particularly suited to endoscopic use articulates an end effector by including an articulation mechanism in an elongate shaft that incorporates an electrically actuated polymer (EAP) articulation locking mechanism actuator. Thereby, additional options for articulation become feasible, especially those that are actively powered and would otherwise dissipate heat and power if required to maintain position. Alternatively, a mechanically actuated articulation mechanism may be designed with reduced strength, and thus size, since the EAP articulation lock mechanism assists in preventing back driving after articulation. Versions of a. EAP articulation locking mechanism lock a pivoting articulation joint and others lock a flexible neck articulation joint.
