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.

VIBRATION CONTROL AND EXPERIMENT OF THREE-RING REDUCER

The three ring reducer is studied both in theory and experiment. In order to improve the dynamic characteristics and reduce the vibration and noise, based on the sensitivity analysis of design parameters of dynamic characteristics, the system geometry parameters are optimized, and the structure of reducer is developed according to the optimum result, then the specimens of reducer are designed and manufactured. The effect of the structure development has been verified by comparing the original and developed reducer through the vibration tests.