Systems Engineering

Systems engineering is a formal process for the development of a complex system driven by a set of established requirements. Common areas of application include:

 

• Computer systems engineering
• Control systems engineering
• Electrical systems engineering
• Mechanical systems engineering
• Software systems engineering

 

All industries are seeing large changes in the 21st century. Competition is ever increasing, the demands from customers are steadily becoming more difficult to achieve, and there continues to be an exponential increase in the applicable technologies that the product may benefit from. As a result, even the simpler historic products are becoming ever more complex with the addition of more functionality through the use of additional components and subsystems. In addition to the design of the product itself, quality, decreased cost, and a quick development cycle are also in great demand.

 

Systems engineering, or SE, originated in the aerospace industry, and has been refined over the past 55 years to support development of large, complex systems by interdisciplinary engineering teams. The general concept is often referred to in many different ways, including systems engineering management, systems engineering design, systems engineering analysis, and systems engineering process. No matter how it is referred to, it relies on the same basic underlying concepts.

 

Any system can be organized into a hierarchical order composed of elements at successive lower and less complex levels:

 

• A system is an interacting collection of items; a set of parts forming a whole. The whole has attributes different than its smaller units.
   
• A subsystem is a functional grouping of components that combine to perform a major function within the system.
   
• A component is a functional unit viewed as an entity for purposes of analysis, manufacturing, testing, maintenance, sourcing.
   
• Parts are the individual items of construction which, when assembled in accordance with the design, form functional components.

 

Systems engineering is driven by a set of requirements derived from the intended use, wants, and needs of the final product or system. These requirements drive the design, development, manufacture, and validation of the system. The first use of systems engineering is to establish actual engineering quantifiable requirements from the customer’s stated use, wants, and needs. This upfront definition of requirements will ‘cast a long shadow’ in the overall development cycle, so it is critical that these requirements be clear and complete, allowing no ambiguity.

 

Once completed, this is followed by the development of conceptual designs or possible solutions. This is where creativity and application of new technology play a major role, creating several possible candidate routes to a successful response to the system engineering requirements. Engineering areas might include mechanical, electrical, electronic, control systems, algorithm development, and software all required to be properly blended together to create a final product. Design reviews, DFMEA, PFMEA, trade studies, human factors, prototype evaluations, computer analysis and tools are all used to sort out the potential candidates, and a primary system design is selected which best meets the requirements. Eventually the process leads to the validation of the design to the established requirements. 

 

Systems engineering requires both systems engineering design and systems engineering management (business management) methods. Both must be applied for effective implementation of the process. The technical and management methods interact with each other and are used throughout the engineering process.

 

To restate, systems engineering is an iterative process, consisting of:
 

• Requirements Definition /Analysis, where the needs of the customer are translated into requirements. Analysis is performed to further define and balance the requirements. It must be noted that one of the principal responsibilities of systems engineering is to continually balance the requirements during the entire product development process, from initiation to final design, and beyond. It can happen that a group within the overall team cannot meet their group’s stated design parameters, and systems engineering will then have to adjust another group’s parameters to alleviate the situation. 
   
• Synthesis, where the established systems engineering requirements are used to create design concepts.
   
•  Evaluation, where trade-off studies and risk analysis are performed to select the design that best meets the requirements (systems engineering analysis). At this point, ‘what is possible or what is not’ regarding the initial customer wants and needs is reasonably well established. The original requirements may have to be adjusted or modified in an iterative process, continuously documented in the product specification, and the changes agreed upon by the customer.
   
• Design of the product, subsystems and components, and allocation of requirements to all the lower levels occurs (systems engineering design).
   
• Develop, Validate, Test: Components, subsystems, and final product are developed and validated against the requirements (systems engineering testing).

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This article was written by Tom Weisgerber, Vice President of Engineering for Kevin Kennedy Associates, who has over 25 years of experience in systems engineering. Tom can be contacted at 317-536-7009, or via email at TomW@KevinKennedyAssociates.com.