Drive control

Control drive has a working element electrically heated by a heating element, a housing containing expansion material, a working piston deployable out of the housing and a proportional stroke controller. A device for detecting a piston displacement position is connected to a regulator circuit that compares actual and demand piston positions to determine the supply of electrical energy to the heating element depending on the comparison result. The control drive has a working element that is electrically heated by a heating element (14), a housing containing an expansion material, a working position that can be deployed out of the housing and a proportional stroke controller for the piton. There is a device (17) for detecting the displacement position of the working piston (13) connected to a regulator circuit (16) that compares the detected actual piston position with a demand position and determines the supply of electrical energy to the heating element depending on the result of the comparison.