USING OPENVSP IN A CONCEPTUAL AIRCRAFT DESIGN ENVIRONMENT IN MATLAB Sebastian Herbst, Adrian Staudenmaier Institute of Aircraft Design, Technical University of Munich Keywords: ADDAM, ADEBO, Conceptual Aircraft Design, OpenVSP Abstract design tools like FLOPS [1, pp. 395–412] could The increasing variety of suitable solutions in also satisfy the demand of handling advanced the aircraft design process which are mainly technologies [2]. Concurrently also new tools driven by new technologies on component level have been developed. Data models (e.g. CPACS offer a large number of feasible design options. [3]), workflow management systems (e.g. RCE Concurrently the process complexity increases [4]) or overall design environments (e.g. CDT as well as the demands on a uniform and [5] or SUAVE [6]). comprehensible data model for the rising The main purpose of ADEBO is to set up number of potential fixed-wing aircraft an aircraft design environment which is flexible, configurations. extensible and user-friendly for conceptual For that reason the Institute of Aircraft Design fixed-wing aircraft design. By using a universal of the Technical University of Munich is data model and a set of tools from different developing the new aircraft design environment branches the design environment covers ADEBO (Aircraft Design Box). It is physics-based as well as empirical methods. The implemented in MATLAB using an object- individual tool application follows the principle oriented programmed (OOP) data model for all of using a level of fidelity that is as high as types of fixed-wing aircraft without any necessary and as fast as possible. Neither the restrictions regarding their geometric shape or design process nor the selection of tools is overall size and mass. As new part of the design narrowed by predefined design patterns which environment OpenVSP is integrated in order to guarantees the consideration of novel use its visualization and calculation technologies and leads to future advanced capabilities. By means of a developed interface aircraft designs. This increasing variety of to MATLAB data can easily be interchanged process capabilities and design solutions can be between the data model and OpenVSP. handled clearly and is well-structured by the Consequently the advantages of both tools can data model ADDAM. General-purpose patterns for tool applications lead to minimized data be used. administration effort and decrease overall process complexity. 1 Introduction As conceptual aircraft design is an engineering discipline which is strongly driven Today’s aircraft design process has changed by mission requirements and initial layout significantly, because new technologies require estimations, the resulting performance during physics-based calculation methods and most trade-off studies needs to be aligned with the semi-empirical methods lack a valid database. geometric shape of the underlying concept. Moreover design solutions that might be named Hence the ability to ensure consistency between unconventional (no tube-wing configuration or the visualized aircraft geometry and the used fossil fuel burning propulsion system) are technical data within the calculations is very desirable and achievable results. For this reason important. NASA developed a software called different approaches have been made: Initially it OpenVSP [7] to rapidly create geometric was examined if enhancements of existing aircraft models without spending much 1 Sebastian Herbst, Adrian Staudenmaier expertise and time in traditional Computer elements depicted in Fig. 1. It consists of a Aided Design (CAD) tools. Today OpenVSP is unique object-oriented data model [9] in order freely available as open source software which to take over and minimize data administration makes it suitable for an integration into effort as well as a set of several tools of ADEBO. Besides using the visualization and different fidelity and purpose. Moreover calculation methods of OpenVSP the export ADEBO comprises a library containing function for *.stl and *.stp CAD files can be databases and frequently used calculation exploited in order to generate geometry input functions and methods. files for simulations (e.g. in OpenSceneGraph). The requirements on using OpenVSP can be divided into hard and soft points and are summarized in Tab. 1 below. Table 1. OpenVSP requirements Hard points: Automatic MATLAB and communication OpenVSP shall exchange data through automatic communication. Consistency The geometry parameters shall be Figure 1. Key elements of ADEBO consistent in both ADDAM and OpenVSP The interaction concept of the key elements databases. themselves and a brief description of the Expand functionality ADEBO shall be able to working procedure with ADEBO is presented in utilize the openVSP the next section. export and analysis functionalities. 2.1 Concept Soft points: Short processing time The processing time to In spite of the high flexibility because of using complete data different tools in a design process, a universally communication should valid procedure in working with ADEBO is be minimized. provided. Initially a data model is required which comprises a configuration object as well as an Artificial Engineer (AE) object (see 2.2). 2 ADEBO – A view inside The user only communicates with the aircraft ADEBO is an environment for conceptual configuration itself or with the AE as the only aircraft design implemented in MATLAB constant elements of a design process. A unique version R2014b©. Due to the utilization of this exception is providing input data directly if an widespread technical computing language [8] a ongoing tool queries additional data. This means large target group ranging from students in set and get data of the aircraft configuration can academia to scientists and engineers in industry be carried out directly just as using can be attained. Furthermore no additional accompanying operations. For running a knowledge of other computing or markup particular tool the user commands the AE to languages like HTML, C++ or Python is start the tool with defined inputs, e.g. required. ADEBO can easily be enhanced and configuration object, visualization flag or tool extended by standardized patterns, which specific input data (for more information see simplifies rapid developments and adjustments 2.3). As visualized in Fig. 2 the user can easily according to new aircraft technologies. The define a purpose based schedule in order to set design environment consists of three key up a design process and fill the configuration object with technical data [10]. 2 USING OPENVSP IN A CONCEPTUAL AIRCRAFT DESIGN ENVIRONMENT IN MATLAB output each. This means the AE calls the tool specific script which automatically runs the input wrapper and starts the tool application. Figure 2. ADEBO command concept 2.2 Data model ADDAM Figure 3. ADEBO wrapper concept ADDAM is an OOP data model specifically developed for the conceptual aircraft design Obviously this wrapper concept generates an process. It consists of two elements: the aircraft overhead in data management and slows down configuration and the AE. The configuration the computational speed compared to running object contains all data of the aircraft and the tool independent from ADEBO. But due to fulfills the software requirements of a data the benefit of being able to use the tool for any model (definiteness, consistency, intelligibility, kind of aircraft configuration and at any stage of expandability, compatibility, and transferability) design process without any changes the as well as the demands for using specific ADEBO wrapper concept decreases effort, time aerospace nomenclature (follow the “engineer and also money for carrying out trade-off way of thinking”, maintain user-friendliness, studies considering multiple aircraft and guarantee a short training period). In configurations and technologies. addition the AE contains the complete tool As already mentioned, OpenVSP as knowledge which links the configuration object standalone software shall be integrated into with the tools. Furthermore the AE is a kind of ADEBO. The main objective is to communicate observer of the configuration object fulfilling automatically with the design environment by data administration tasks. One major advantage exporting data from ADDAM into OpenVSP of ADDAM is that every value is assigned to a and also import data from OpenVSP into the specific unit which can be of the type SI data model (see Fig. 4) (standard) or imperial unit system. At any time the unit can be converted or translated by the data model itself. Furthermore each value has a history which records every change in the value itself and its unit as well as its value type and its used calculation method and applied tool in order to determine the value [9, 11]. Figure 4. OpenVSP utilization in ADEBO 2.3 Tool utilization Each tool shall be implemented as efficient and as fast as possible independent from ADEBO. 3 Integrate OpenVSP into ADEBO This also means no existing tool needs to be Integrating OpenVSP will increase the changed or adjusted in order to be suitable for capabilities of ADEBO by establishing *.stl ADEBO. The design environment provides a files easily, using its geometric and procedure for the tool integration following the aerodynamic calculation functions as well as the principle of using a specifically developed ability to create mesh models for initial wrapper for each tool. Figure 3 shows the computational fluid dynamics (CFD) concept of applying a wrapper for the input and calculations.