A control device includes a main servocontrol loop having a servocontrolled system, and a compensation device on the input side of the control device. The control device includes an internal loop that receives a first signal derived from the main servocontrol loop as input, and generates, as a function firstly of the first signal and secondly of a second signal characteristic of a parameter of the servocontrolled system, an error signal characteristic of the difference between said second signal and a theoretical signal determined using a model. The error signal being injected into the main servocontrol loop to correct the control of the servocontrolled system. The internal loop and/or the main loop include a variable gain amplifier, and the control device controls the gain of the variable gain amplifier.