Method for detecting the position of an actuator element

A method for detecting a position of an actuator element of an actuator arrangement, comprising

• at least one actuator element movable in two opposing directions by two adjustment elements, wherein the adjustment elements are formed with electrically controllable shape memory alloy wires, and
• a control unit electrically connected to the adjustment elements,
• wherein the control unit has a controllable control circuit which is configured to connect one or the other adjustment element as required to a voltage source in a pulse width-modulated manner, and
• wherein only one two-wire connection is formed between the control unit and the adjustment elements, the method comprising:
• periodically recording by a resistance measurement circuit formed in the control unit the resistance values of the two adjustment elements,
• at an energization time of a currently actuated adjustment element, determining and storing the resistance value of the adjustment element and, in a subsequent pause in energization, the resistance value of a respective other adjustment element,
• forming and comparing a differential value of the two determined resistance values with pairs of values which are stored in a table and describe a correlation between the resistance differential value and a position of an adjustment element, and determining the position of the actuator element therefrom.