The course provides the elements for the modelling and the analysis of mechanical systems equipped with actuators and control. Assess the stability of a controlled mechanical system. Develop control techniques for complex systems considering the complete mechatronic system made up of mechanical system – actuation system – control logic.
Description of the covered arguments
Stability of mechanical systems. State dependent force fields, both conservative and non-conservative. Mechanical systems under the influence of force fields: general description, equations of motion and linearization, solution of the equations of motion, discussion of stability conditions, position and velocity force fields. Fluid forces on a rigid body including aerodynamic instability (flutter instability of a wing-like profile). Contact forces between rigid bodies including rolling (hunting instability of a wheelset).
Introduction to the control of mechanical systems. Simulation models. State variables. Harmonic transfer function. Laplace and Fourier transform. Frequency response function. Block diagram representation.
Stability analysis of controlled mechanical systems. Root Locus. Bode and Nyquist diagram. Nyquist criterion. Requirements of a controlled dynamic LTI (linear time invariant) SISO (single input single output) system: synthesis of the control logic, definition of performance and robustness indexes
PD and PI controller. Application to 1 dof and 2 dofs vibrating systems
Modern approach to the synthesis of a controller. Pole placement method.
Hydraulic actuators: basic components, performances, models, hydraulic circuits in automation processes.
Electric actuators: basic components, performances, characteristic curves. DC drives: control s. AC drives: control and power electronics, models for synchronous brushless motors. Control of electric drives: basic principles, criteria for torque and speed control, performances.
Pneumatic actuators: basic components (cylinders, valves, …), model of controlled air spring.
K. Ogata, Modern Control Engineering, Prentice Hall Ed.
L. Meirovitch, Dynamics and control of structures, John Wiley & Sons Ed.
Other references in English:
L. Meirovitch, Fundamentals of Vibrations, McGraw-Hill, 2001
R. C. Dorf, R. H. Bishop, Modern Control Systems, Prentice Hall, 2001
Merrit, Hydraulic control systems, John Wiley & Sons
Other references in Italian:
G. Diana, F. Resta, Controllo di sistemi meccanici, Polipress, Milano, 2006
G. Diana, F. Cheli, Dinamica e vibrazioni dei sistemi meccanici, UTET, 1993
P. Bolzern, R. Scattolini, N. Schiavoni, Fondamenti di controlli automatici, McGraw-Hill
R. Manigrasso, M. Mauri, F. L. Mapelli, Azionamenti Elettrici Parte I, Generalità e Macchine Rotanti, 2007