Contents I. Introduction
In mechatronics, especially in mechatronic system control, an ongoing necessity for further advancement in developing the methods for controlling electric drives containing elements with different types of parasitic effects is inevitable. In this case, the parasitic effects are caused by a flexible connection between an actuator and a load. Various methods of a mechatronic system control design affecting different aspects of control process are known and used. The term “sensitivity of a dynamical system” generally expresses the change in the behaviour of such a system in both static and dynamical mode caused either by a variability in parameters of its structure or by a variability in the parameter values of its elements. The article evaluates the sensitivity of the system building on two basic types of the control proposals - a classic feedback control and a cascade control. The system sensitivity is analysed on the basis of the absolute sensitivity of function to the change of selected parameter value of the mechatronic system, as well as the control subsystem. The system absolute sensitivity is used as the starting point for analysing the system relative differential sensitivity. The sensitivity is monitored in terms of the impact of parameter variability on the response in the form of step response of closed control loop based on absolute and relative sensitivity of system transfer function. Another means of the sensitivity analysis is to assess the impact of changes in selected parameters on the system frequency-response characteristic, focusing on logarithmic frequency-response characteristic, i.e. Bode diagram.
