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This paper explores the possibility of constructing two-terminal mechanical devices (one-ports) which are lossless and adjustable. To be lossless, the device must be passive (i.e., not requiring a power supply) and nondissipative. To be adjustable, a parameter of the device should be freely variable in real time as a control input. For the simplest lossless one-ports, the spring and inerter, the question is whether the stiffness and inertance may be varied freely in a lossless manner. We will show that the typical laws which have been proposed for adjustable springs and inerters are necessarily active, and that it is not straightforward to modify them to achieve losslessness, or indeed, passivity. By means of a physical construction using a lever with moveable fulcrum, we will derive device laws for adjustable springs and inerters which satisfy a formal definition of losslessness. We further provide a construction method which does not require a power supply for physically realizable translational and rotary springs and inerters. The analogous questions for lossless adjustable electrical devices are examined. [ABSTRACT FROM AUTHOR]

The article discusses the highlights of the 53rd IEEE Conference on Decision and Control (CDC) held on December 15-17, 2014 in Los Angeles, California. Topics discussed include ways to develop resilient cyber-physical infrastructures, the control, dynamics and reconstruction of collective behavior and the use of big data analytics for cyber-physical systems. The event featured speakers like Lillian Ratliff, Claire Tomlin and Miroslav Krstic.

We discuss adding a measure of scheduling to the popular Anti-Windup design. The main idea is to develop a scheme in which the Anti-Windup gains depend on how much the actuator command exceeds the saturation bound. The aim is to design and implement more aggressive Anti-windup gains in lower levels of saturation. Global stability and performance are addressed by adding an outer-loop Anti-windup compensation which become active when the system is in higher levels of saturation. We present results for both static and dynamic Anti-Windup gains, along with the convex synthesis LMIs. Benefits of the proposed design method are shown using well-known examples. [ABSTRACT FROM AUTHOR]

We investigate the effects of deferring the activation of anti-windup by allowing actuators to remain in the saturated regime longer, without any assistance. The basic idea is to apply anti-windup when the performance of the saturated system faces substantial degradation. For this, we present a modified anti-windup scheme along with the appropriate LMIs to obtain the gains. For two examples, we show that the modified anti-windup scheme renders better performance than the immediate application of anti-windup. [ABSTRACT FROM AUTHOR]

Focuses on the use of scales in the reduction of the conservatism encountered in multiobjective approaches. Consequences of using scalar scales; Analysis on output feedback synthesis; Effectiveness of multiobjective approach.

Investigates the control of linear parameter-varying systems with time-varying real uncertain parameters. Internal stability and disturbance attenuation of the system; Solvability conditions for dynamic output feedback controllers; Determination of the additional coupling constraints which destroys the convexity of the system.

Studies the design of output feedback compensators used for controlling uncertain systems. Variety of iterative approaches to controller design; Existence of full order compensator equal to a set of constant matrices; Breakdown of the compensator design.