Patent ID: 8246303

Claim:
An active twist hollow beam system comprising: a hollow beam, the beam being split along a longitudinal length of the beam; and an actuator arranged to move a first split surface and a second split surface of the beam in a longitudinal direction relative to each other along the longitudinal length of the beam, inducing a twist in the beam, each of said split surfaces having a plurality of protrusions spaced apart along the longitudinal direction, the actuator comprising a plurality of solid thermal expansion blocks, each of the solid thermal expansion blocks comprising elastomer or polymer, the actuator further including a plurality of mechanical compression blocks arranged in an alternating pattern with the solid thermal expansion blocks, wherein, of the mechanical compression blocks and the solid thermal expansion blocks, only the solid thermal expansion blocks are in contact with an electrical resistance heater, each of the solid thermal expansion blocks being located between and attached to at least one of the protrusions on the first split surface and at least one of the protrusions on the second split surface, wherein in operation, for at least one of the solid thermal expansion blocks, the electrical resistance heater heats the solid thermal expansion block, causing expansion of the solid thermal expansion block in the longitudinal direction, thereby moving the split surfaces relative to each other in the longitudinal direction.