1. Nonlinear passive wrist.
Nonlinear passive wrist. (A) Loading and unloading curves for pretensioned superelastic SMA wire; energy loss approximated by the shaded rectangular region. (B) One-DOF wrist joint and corresponding torque/deflection model. SMA wire is connected to stop bars and flexible tendon strings, which are slack when unloaded. This design prevents deadband about the center. (C) Nonlinear wrist performance in comparison to critically damped linear system. (D) Simulation of wrist behavior in comparison to the spring-damper system. Initial energy and maximum torque are set equal in both cases. (E) Comparison of critically damped and SMA single-axis joints for absorbing energy from collision with a metal ball.
Hao Jiang et al. Sci. Robotics 2017;2:eaan4545
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