Roberto Zanasi

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A nonlinear variable structure (VS) system is presented, suitable for smooth trajectory generation in motion control system. Joined to a rough reference trajectory generator (step, ramp, etc.) it provides smooth output signals according to user-selectable bounds on trajectory derivatives. The bounds on output derivatives can be changed during system(More)
Based on the theoretical results from optimal control theory and sliding mode control, this paper proposes a discrete time nonlinear control law that guarantees the minimum time global stabilization of a chain of three integrators with bounded control input. Moreover, the proposed control law allows the minimum time trajectory tracking for a wide class of(More)
In this paper a digital filter is proposed for the generation of smooth set points for motion control systems. The proposed nonlinear filter produces profiles with bounded velocity and acceleration starting from rough reference signals (steps and ramps). An actual implementation of the filter for a tile printing machine is presented and experimental results(More)
Lead, lag and lead–lag compensators are among the most utilised control architectures in industrial and process engineering, and for this reason they have always received a great deal of attention (Franklin, Powell, and Emami-Naeini 2006). The recent literature shows a renewed interest in the design of lead/lag-type controllers (Messner, Bedillion, Xia, and(More)
A filter for trajectories smoothing is presented. The filter provides an output reproducing the input trajectory if this is compliant with given constraints on the velocity, the acceleration and the torque required for tracking it. Otherwise, the filter approximates the input profile guaranteeing that the output trajectory satisfies all the kinematic and(More)
The paper presents a direct digital method to the design of a discrete lead-lag compensator for a robust control. The design specifications on phase margin, gain margin and crossover frequency of the close-loop system can be obtained by using numerical and graphical solutions. The discrete design method proposed in the paper is also compared with the(More)