This paper studies problematic of a mechanical system composed of different coupled parts submitted to a high speed shock and proposes analysis of anti vibratory passive and active methods based on an experimental and theoretical coupled approach. After a shock, different parts of the system oscillate. If one of them is excited at a particular frequency, such as its proper frequency, important oscillations appear and can lead to the deterioration of the system by introducing important stresses. In this paper, we propose an analysis in order to understand this kind of problem and what we can do to avoid it. Firstly, we discuss problematic and we expose the studied system. In a second time, we develop two approaches of modeling that allow us to understand the phenomenon by carrying out numerical simulations. Then cross checking of model is completed via experimental study on drop test bench. Passive minimization method of vibrations based on experimental and theoretical coupled approach is exposed. Finally, a comparative analysis of different methods of control and experimental results of controlled system are presented.

The present paper describes a novel concept of actively controlled Hiller type servopaddle to achieve rotor primary control. The blades on the swashplateless rotor are coupled to a servopaddle with a piezoelectrically actuated aileron. The aileron commands the paddle pitch which generates a change in the paddle ap angle and blade pitch angle via a mechanical linkage. The system { blade, paddle, aileron} is independent from any other { blade, paddle, aileron} assembly. Therefore, the active servopaddle can create both cyclic and collective inputs. A four degree-of-freedom analysis including aileron dynamics has been developed to predict the dynamic behavior and assess the feasibility of such a swashplateless rotor. The analysis is used to investigate the effect of system parameters on the blade control authority.

This communication proposes an original method to define a low-cost manufacturing process for hydraulic spool valves in the case of very low production rate. A valve is usually completely defined by three characteristic curves obtained by two tests: a pressure gain test and a flow gain test. The aim is to limit the number of tests and in particular to avoid the flow gain test that is quite long to achieve. The method only uses a single metrology operation and the pressure gain curve to manage the spool flanks grinding while ensuring the specified hydraulic characteristics. The method is established by a model-based approach. It is then validated by experimental tests on two different valves.

This paper studies problematic of a mechanical system composed of different coupled parts submitted to a high speed shock and proposes analysis of anti vibratory passive and active methods based on an experimental and theoretical coupled approach. After a shock, different parts of the system oscillate. If one of them is excited at a particular frequency, such as its proper frequency, important oscillations appear and can lead to the deterioration of the system by introducing important stresses. In this paper, we propose an analysis in order to understand this kind of problem and what we can do to avoid it. Firstly we discuss problematic and we expose the studied system. In a second time, we develop two approaches of modeling that allow us to understand the phenomenon by carrying out numerical simulations. Then cross checking of model is completed via experimental study on drop test bench. Passive minimization method of vibrations based on experimental and theoretical coupled approach is exposed. Finally a comparative analysis of different methods of control is presented.