Simulation technology powers the next generation of unmanned aircraft systems.

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Ansys-Apache chip package system (CPS) EMI flow. Image: Ansys

The aerospace and defense community is considered a pioneer in physics-based simulation development and one of its earliest adopters. Design engineers use simulation software to create virtual representations of practically anything and everything, including complete unmanned aerial systems (UAS).

UASs may seem like a new or futuristic concept due to their prominent role in recent high-profile surveillance and reconnaissance missions and natural disasters. However, this technology is actually quite mature, and the aerospace and defense industry has been implementing UASs for several decades. In fact, space satellites are considered as some of the first unmanned systems.

In order to meet to the U.S. Department of Defense's growing requirements of future roadmaps for UAS development and deployment, the aerospace and defense industry must increase the reliability and endurance of UASs, as well as expand their capabilities, including potential commercial use.

Managing the size, weight, and power (SWaP) requirements of next-generation aircraft pose critical design challenges such as power consumption optimization, thermal management, and fail-proof reliability. Simulation technology enables the modeling of these complex effects, so that engineering organizations can meet stringent military performance specifications and stay within tight budget and time constraints. The use of simulation technology to create a virtual prototype and perform early analysis enables the development of a final product at a lower cost, within a shorter design cycle, and improved overall reliability.

Power is the central design issue since it governs the size, endurance, and reliability of the entire system. Effective power management can result in energy longevity of the UAS and greater endurance under varying operating conditions. Managing power is critical to SWaP tradeoffs and allows for longer missions or enables miniaturization of the unit to extend its application profile. Military systems are held to high-reliability standards, which are dependent on the electronic system’s consistent performance, beginning with reliable components.

The growing use of commercial off-the-shelf (COTS) components in UASs presents a new challenge for guaranteeing system dependability. While COTS have the advantage of reducing design cost and time to market for processors and field-programmable gate arrays (FPGAs), the power consumed and heat generated pose severe reliability concerns. This is especially true for military applications functioning in extreme temperature environments. By reducing component power consumption early in the design stage, it also reduces the amount of heat generated and helps ensure reliable system operation in the target environment. In addition, it mitigates the risks of depleting battery power, as well as electrical and thermal reliability issues to help avoid field failures.

Simulation solutions
Engineering simulation delivers the tools necessary to meet the overlapping requirements of quality, cost, and schedule of UAS design and development. As UAS capabilities grow more complex, engineering simulation solutions can add value when:

  • It is applied early to all aspects of UAS design (fluid dynamics, structural mechanics, and electromagnetic and thermal simulation capabilities);
  • The interaction of system-level physics is included in the analysis (for example, fluid and structures for wing flutter, structures, and electromagnetics for load-bearing antenna design, structural and thermal for component stress analysis);
  • The workflow is seamlessly integrated across physics with existing tools such as computer-aided design (CAD) and product lifecycle management (PLM);
  • Hardware is designed for low power to fit into the power envelope of the supply system; and
  • Power optimization opportunities are identified across the design in a complex system.

However, engineering simulation tools must offer more than technical capability. The unique nature of UAS designs make it critical to capture the design process and intent in order to systemize and scale for future applications.

As military and commercial applications expand the role of unmanned systems, simulation solutions providers must address the challenge of ensuring that power supplies meet power and thermal requirements. Using a multiphysics approach initiated early in the design phase can help simulate power consumption and thermal dissipation for these complex systems, enabling miniaturization, endurance, and reliability for onboard electronics.