Equivalent power method of reducing the affects of voltage variation during active material actuation

An equivalent power method adapted for implementation by a controller communicatively coupled to a shape memory alloy actuator, composing a circuit, presenting a maximum available power output (Omax), and for reducing the effects of voltage variation during a plurality of actuation events, and determining an applied real output, said method comprising the steps of:

• a) determining an ideal voltage within the circuit;
• b) calculating an ideal output based on the ideal voltage, such that the output is operable to ideally activate the actuator;
• c) determining an ideal power based on the ideal output and ideal voltage;
• d) measuring a real voltage for a current one of said plurality of actuation events;
• e) calculating an initial real output based on the ideal voltage, ideal output, and real voltage, such that the applied real output and real voltage determine a real power, and the real power is equivalent to the ideal power;
• f) comparing the initial real output to Omax, and setting the applied real output to Omax when the initial real output is greater than Omax, and setting the applied real output to the initial real output when the initial real output is less than Omax;
• g) determining a difference (D) equal to the initial real output minus the maximum available power output, and storing D when positive;
• and
• h) compensating during a subsequent actuation event, when D is positive, by calculating a subsequent real output less than the available output during the subsequent actuation event and then adding at least a portion of D to the subsequent real output, so as to determine a subsequent applied output.