Ratcheting shape memory alloy actuators and systems and methods including the same

A ratcheting shape memory alloy actuator that is configured to adjust an orientation of a first structure relative to a second structure, the actuator comprising:

• a first bracket that is configured to be operatively coupled to the first structure;
• a ratcheting assembly that is operatively coupled to the first bracket;
• a second bracket that is configured to be operatively coupled to the second structure;
• and
• a shape memory alloy torque tube that is located between and operatively coupled to the second bracket and to the ratcheting assembly, wherein:
• (i) the shape memory alloy torque tube applies a first motive force to the ratcheting assembly upon deformation from a first conformation to a second conformation;
• (ii) responsive to receipt of the first motive force, the ratcheting assembly selectively adjusts the orientation of the first structure relative to the second structure;
• (iii) the shape memory alloy torque tube applies an opposed second motive force to the ratcheting assembly upon deformation from the second conformation to the first conformation;
• and
• (iv) the ratcheting assembly dissipates the second motive force without relative motion between the first structure and the second structure.