Actuator with an electric motor

An actuating drive including an electronically commutated electric motor which operates with a position-dependent summed torque and which, using a torque controller and a controlled system, is able to be adjusted to a selectable, torque-dependent setpoint value according to a continuously increasing torque-time characteristic curve, the torque controller being able to have supplied to it a torque-dependent actual value of the electric motor in addition to the set point value to derive a control signal, wherein the torque controller (RM) emits the control signal as a setpoint position (⊖setpoint), and feeds it to a downstream position controller (RP);

• until a predetermined threshold torque (MSW) which is smaller than the maximum torque (Mss) of the electric motor is reached, the setpoint position (⊖setpoint) can be fed unchanged to the position controller (RP) and is used together with the actual position (⊖actual) of the electric motor to derive the control signal (u) for the controlled system (S);
• and subsequent to exceeding the threshold torque (MSW), the setpoint position (⊖setpoint) can be fed to the position controller (RP) as a changed setpoint position ({tilde over (⊖)}setpoint) until the predetermined setpoint position is reached, the changed setpoint position ({tilde over (⊖)}setpoint) repeatedly increasing in an abrupt manner according to the increase in the following peak values (P1 through P4) of the increasing summed torque.