SLACK SMA WIRE IN SMA ACTUATOR ASSEMBLIES
A method of measuring the degree of slack of plural lengths of shape memory alloy wire where at least one of which is held slack, the method comprising: heating the lengths of shape memory alloy wire to cause contraction of the lengths of shape memory alloy wire; measuring an electrical characteristic of the lengths of shape memory alloy wire during said contraction of the lengths of shape memory alloy wire; and deriving a measure of the degree of slack of the lengths of shape memory alloy wire from the measured electrical characteristic.