DESIGNING REDUCED-ORDER CONTROLLERS OF MIXEDSENSITIVITY PROBLEM FOR FLIGHT CONTROL SYSTEMS

Based on linear matrix inequalities (LMI), the design method of reduced order controllers of mixed sensitivity problem is studied for flight control systems. It is shown that there exists a controller with order not greater than the difference between the generalized plant order and the number of independent control variables, if the mixed sensitivity problem is solvable for strict regular flight control plants. The proof is constructive, and an approach to design such a controller can be obtained in terms of a pair of feasible solution to the well known 3 LMI. Finally, an example of mixed sensitivity problem for a flight control system is given to demonstrate practice of the approach.

Research on Dithianon to Evaluate Suspects of Reduced Sensitivity of <i>Venturia inaequalis</i>with Different Methodologies in Italian Apple Areas

Dithianon is a multi-site fungicide and has never been object of suspects and reports of reduced sensitivity and activity. Italian IFP technicians had the suspect of reductions of activity by this fungicide on Venturia inaequalis. Methodologies, in vitro and in vivo were carried out to verify this suspect. Populations poorly controlled with suspects on dithianon and sensible ones were utilized. The tests in vitro permitted to evidence light and non-significant reductions of sensitivity of poorly controlled populations with respect to sensible ones. In vivo tests on seedlings were non-reliable for a general low activity of dithianon. On the contrary, the original in vivo methodology on grafted apple plants showed several reductions of activity, with moderate levels and a spot distribution in orchards. The cause was probably due to the increased treatments with dithianon caused by problems on other groups of fungicides and by a high infective pressure in some years. It is discussed if this reduction can be considered a resistance phenomenon or a temporary modification of the interactions of plant-fungus-fungicide.

Advance of Study on Design Methods of Hydraulic System of Radio Remote Control of Construction Machinery

The working principle of radio remote controlling of construction machinery should be that signals of the radio wave from the transmitter obtained in the receiver were controlled and then changed into electronic analog or digital signals which can be used to drive different actuators and mechanisms of the vehicle.The vehicle could be acted by following the controlling instructions sent by the operator.The best operation mode of construction machinery is suitable not only to manual operating but also to remote controlling in the same vehicle.The design methods of the hydraulic system used for the radio remote controlling of construction machinery are discussed.The design methods of hydraulic circuits for the actuators controlled by solenoid on-off type valves,hydro-electronic multi-way proportional valves,closed loop proportional servo driver or three-way proportional reducing valves are discussed in detail (with real example).The design methods of the power shift transmission of electro-hydraulic controlling,the devices of braking and the directional streering are discussed in this paper.

Particle Swarm Optimization for the Design of H∞ Static Output Feedbacks

The design of H∞ reduced order controllers is known to be a non-convex optimization problem for which no generic solution exists. In this paper, the use of Particle Swarm Optimization （PSO） for the computation of H~ static output feedbacks is investigated. Two approaches are tested. In a first part, a probabilistic-type PSO algorithm is defined for the computation of discrete sets of stabilizing static output feedback controllers. This method relies on a technique for random sample generation in a given domain. It is therefore used for computing a suboptimal Ha static output feedback solution, In a second part, the initial optimization problem is solved by PSO, the decision variables being the feedback gains. Results are compared with standard reduced order problem solvers using the COMPIeib （Constraint Matrix-optimization Problem Library） benchmark examples and appear to be much than satisfactory, proving the great potential of PSO techniques.

Derivation and analysis on the analytical structure of interval type-2 fuzzy controller with two nonlinear fuzzy sets for each input variable

Type-2 fuzzy controllers have been mostly viewed as black-box function generators. Revealing the analytical structure of any type-2 fuzzy controller is important as it will deepen our understanding of how and why a type-2 fuzzy controller functions and lay a foundation for more rigorous system analysis and design. In this study, we derive and analyze the analytical structure of an interval type-2 fuzzy controller that uses the following identical elements: two nonlinear interval type-2 input fuzzy sets for each variable, four interval type-2 singleton output fuzzy sets, a Zadeh AND operator, and the Karnik-Mendel type reducer. Through dividing the input space of the interval type-2 fuzzy controller into 15 partitions, the input-output relationship for each local region is derived. Our derivation shows explicitly that the controller is approximately equivalent to a nonlinear proportional integral or proportional differential controller with variable gains. Furthermore, by comparing with the analytical structure of its type-1 counterpart, potential advantages of the interval type-2 fuzzy controller are analyzed. Finally, the reliability of the analysis results and the effectiveness of the interval type-2 fuzzy controller are verified by a simulation and an experiment.