Patent ID: 7176413

Claim:
A method for controlling one or more shape-memory actuators, each comprising at least one shape-memory element, which can change its shape upon variation of its temperature beyond a transition value, in which means are arranged for supplying an electric current through the shape-memory element of each shape-memory actuator, wherein said method includes the following steps: detecting environmental conditions of each shape-memory actuator by monitoring or evaluating the temperature of the shape-memory element and, optionally, monitoring or evaluating or more parameters chosen among: environment temperature, electric supply voltage, and controlling the intensity and/or duration of electric current supplied to each shape-memory element as a function of detected environmental conditions, wherein said monitoring or evaluating said temperature of the shape-memory element is: (i) detected on the basis of the impedance of the shape memory element before activation thereof, or (ii) detected by monitoring the actuator impedance during actuation, or (iii) estimated on the basis of: the heat exchange pattern, including the duration of actuation pulses and of cooling rest times, and the electric power given to the actuator, and the starting temperature of the actuator.