Mechatronic power transmission chains - Implementing estimation models for preliminary design

The need for a multi-disciplinary approach to today's power transmission systems has led to the development of design tools that maintain a high-level vision of the system, while providing sufficient detail to make choices. Indeed, to meet the current demand for electromechanical drive systems that are ever "cheaper, safer, lighter and greener", with ever shorter design times, engineers need to find complete actuator solutions ever more quickly. In some of these application areas, such as aeronautics and other means of transport, tight safety and availability constraints mean that actuator components often have to be qualified and designed specifically for their applications. As a result, engineers have to work to specific design requests from equipment manufacturers, which postpones the availability of information on the characteristics of the device under development. Estimating these characteristics at the very start of a project, during the preliminary design stages, represents a considerable advantage, for example in supporting a choice of technology or working upstream on the integration of the device to be designed.

A methodology meeting this need for technical information during the preliminary design stages is presented in two articles. The present article describes the general aspects of the chosen modeling method: estimation models, scaling models, design constraints for mechatronic components and an example of the use of scaling in dimensioning. A second article [BM 8 026] contains a set of models by technological family, to serve as a "toolkit" from which the engineer can draw or be inspired to create specific estimation models.

This article describes a simple analytical modeling methodology that can be adapted to the main components typical of mechatronic power transmission chains. Particular attention is paid to models of electromechanical components, which are less developed in the literature than hydraulic components, and which often represent new solutions in mechatronics. These models can also be used to estimate the main parameters needed for integration studies (mass, overall dimensions), system simulation and operating limit calculations. The chosen modeling approach is based on scaling laws, and requires only a reference of an existing component (for each technology selected), in order to extrapolate its characteristics over a wide range.