International audienceThis article presents estimation models for the model-based preliminary design of electromechanical actuators. Models are developed to generate all the parameters required by a multi-objective design, from a limited number of input parameters. This is achieved using scaling laws in order to take advantage of their capability to reflect the physical constraints driving the actuator's component sizing. The proposed approach is illustrated with the major components that are involved in aerospace electromechanical actuator design. The established scaling laws provide the designer with parameters needed for integration into the airframe, power sizing, thermal balance, dynamics, and reliability. The resulting estimation models are validated with industrial data

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This paper presents a methodology for the optimal preliminary design of electro-mechanical actuators. The main design drivers, design parameters and degrees of freedom that can be used for preliminary design and optimization of EMA are described. The different types of models used for model based design (estimation, simulation, evaluation and meta-model), and their associations are presented. The process preferred for its effectiveness in terms of flexibility and computational time is then described and illustrated with the example of a spoiler electromechanical actuator. The proposed approach, based on meta-models obtained using the surfaces response methods and scaling laws models, is used to explore the influence of anchorage points and transmission ratio on the different design constraints and the overall mass of the actuator.

Please cite this article as: J-C. Maré, J. Fu, Review on signal-by-wire and power-by-wire actuation for more electric aircraft, Chinese Journal of Aeronautics (2017), doi: http://dx.

PurposeTo develop structured guidelines for the synthesis of dynamic force simulators that are required for the testing of high speed aerospace actuators. To provide realistic and proven solutions at both test bench hardware and control design levels.Design/methodology/approachThe state of the art in control design applied to load simulators in mainly based on complex controllers and does not take into account practical considerations. The objective of the present work is to provide generic preliminary design rules to ensure that the test bench architectures (frame, power transmission and control) and the components specifications are consistent with the targeted performance. Once selected the appropriate power transmission architecture, a linear approach is used as a foundation to generate design rules. Then, preliminary design is achieved thanks to the introduction, as early as possible, of the unavoidable technological defects.FindingsA step‐by‐step methodology allows the designer to select the controller architecture and to specify components with special care to their consistency with the required dynamic performance. The linear then practical approach generates key rules that can be used in the very early phase of the test bench design.Originality/valuePractical considerations on the components static and dynamic limitations are introduced progressively to make the natural test bench performance as consistent as possible with the performance requirements. Consequently, the controller becomes simpler to design and robust.

The force equalization of a hybrid actuation system combining one servo-hydraulic actuator and one electro-mechanical actuator operated in position control and in active/active mode is addressed for safety critical applications such as primary flight controls. In a first step, an accurate virtual test bench is built to facilitate the analysis of force fighting and the assessment of the performance and robustness of the proposed force equalization strategies. It is validated from real experiments performed for the aileron actuator of a single-aisle commercial aircraft. Static force equalization is achieved first by adding equalization offsets in the position control loops as a function of the integral of the force difference between actuators. In order to keep a high level of segregation, the authority for this action is limited to 4% of the total actuator stroke. The dynamic force equalization is performed by forcing the two actuators to follow the same path. Thus, a trajectory generator is introduced to output the required position, velocity and acceleration from the position set point with realistic reproduction of the actuator power limits. Feedforward actions are used to compensate the major and invariant effects such as servo-hydraulic actuators functional flow and electro-mechanical actuator inertial torque. In this way, the pursuit errors are significantly reduced without decreasing robustness. Then, the accurate virtual test bench is used to assess the robustness of the force equalization strategy by analyzing the sensitivity of performance indicators to parameters and operating conditions. It is shown that the proposed force equalization scheme meets all the requirements, including segregation, robustness and simplicity.

The promises of Model Based Design have led to the development of numerous methodologies and software tools, especially for the specific or detailed design stages, from controller design to finite element analysis. However, the Model Based Design of actuation systems lacks methodologies and expressive simulation models that are suited to preliminary design, where key technical decisions are taken considering various design alternatives and few available design details. In order to fill this gap, the present paper illustrates how scaling laws and acausal modelling can be used as a design tool, exploiting inverse simulation capabilities to evaluate technological alternatives quantitatively from limited design detail information. The application of the modelling approach is shown for two major components of mechanical transmission systems: roller bearings and ball and roller screws. The scaling laws presented are validated with manufacturers' data. To conclude, the suitability of the proposed methodology is illustrated with the preliminary sizing of an electromechanical actuator for an aircraft primary flight control surface (aileron).

PurposeThe purpose of this paper is to develop accurate model and simulation of mechanical power transmission within roller‐screw electromechanical actuators with special attention to friction, compliance and inertia effects. Also, to propose non‐intrusive experiments for the identification of model parameters with an integrator or system‐oriented view.Design/methodology/approachAt system design level, the actuation models need to reproduce with confidence the energy losses and the main dynamic effects. The adopted modelling methodology is based on non‐intrusive measurements taken on a standard actuator test‐bench. The actuator model is first structured with respect to the bond‐graph formalism that allows a clear identification of the considered effects and associated causalities for model implementation. Various approaches are then combined, mixing blocked or moving load, position or torque control and time or frequency domains analysis. The friction representation model is suggested using a step‐by‐step approach that covers a wide domain of operation. The model is validated under varying torque and speed conditions.FindingsA structured model is introduced with support of the bond‐graph formalism. Combining blocked/moving load and time/frequency domain experiments allows the development of progressive model identification. An advanced friction representation model is proposed including the effects of speed, transmitted force, quadrant of operation and roller‐screw preload.Originality/valueMechanical transmission energy losses and dynamics are modelled in a system‐oriented view without massive need to confidential design parameters. Not only speed but also load and operation quadrant effects are reproduced by the proposed friction model. The non‐intrusive experimental procedure is made consistent with use of a standard actuator test‐bench.