2.5 - Research: Weeding Out a Solution

In this activity you will address the following scenario:

A UAS is to be designed for precision crop-dusting. In the middle of the design process, the system is found to be overweight.

• Two subsystems – 1) Guidance, Navigation & Control [flying correctly] and 2) Payload delivery [spraying correctly] have attempted to save costs by purchasing off-the-shelf hardware, rather than a custom design, resulting in both going over their originally allotted weight budgets. Each team has suggested that the OTHER team reduce weight to compensate.
• The UAS will not be able to carry sufficient weight to spread the specified (Marketing has already talked this up to customers) amount of fertilizer over the specified area without cutting into the fuel margin. The safety engineers are uncomfortable with the idea of changing the fuel margin at all.

Write a response describing how you, as the Systems Engineer, would go about resolving this issue. Use your imagination, and try to capture what you would really do. Take into account and express in your writing the things you’ve learned so far in this module: What are your considerations? What are your priorities? What do you think about the future prospects for the “next generation, enhanced” version of the system as a result of your approach?

Weeding Out a Solution

Considerations

            As the systems engineer, I have been confronted with resolving the issue of determining how to reduce weight on an unmanned aerial system (UAS) designed for precision crop-dusting. Two teams, guidance, navigation & control, and payload delivery have both attempted to save costs by purchasing off the shelf hardware. Both teams have gone over the allotted weight budget and both teams have suggested the other team reduce weight. As the systems engineer, it is important to be unbiased and knowledgeable about each person’s individual job in order to avoid further conflicts during the design process of the unmanned aerial vehicle (UAV).

            The customer must be a consideration and a priority. How will customers react to the delayed schedule of the UAV? With the UAV being overweight and the marketing team discussing the spread capabilities of the UAV to customers, it could be necessary to lower the price of the UAV due to the UAV being less capable than what the company has already stated to customers. The customers are expecting to be able to purchase the UAV by a specific date. It would not look good on the business if the delivery date of the UAV was changed. However, it may be necessary considering the UAV would be less capable than what the marketing team has stated.

            One of the first steps I would take would be to review the lifecycle process technical review of phases and control gates. This process is setup to stop designers and manufacturers from continuing the development of a UAV unless a review has been completed (Terwilliger, Burgess, & Hernandez, 2013). By utilizing a phase-gate approach to the development of this UAV, and completing a corresponding review of each step in development, it is likely that the issue of the UAV being overweight would not have occurred in the first place. I would want to determine what parts were causing the UAV to become overweight. Even though the project is already over its allotted budget, it may be beneficial to create custom designs for hardware in order to reduce the weight of the UAV. The off the shelf hardware may be a critical factor in the issue of the UAV being overweight. It would be necessary to determine if custom designs for hardware would reduce the weight of the UAV.

Priorities

            The main priority in this scenario is to determine how to reduce the weight of the UAV while also keeping the customers happy with the design since the marketing team has already discussed the capabilities of the UAV. Taking the fuel margins into consideration, and under the recommendation of the safety engineers, the fuel levels should not be adjusted. It could be hazardous for people on the ground if the UAV has a short flight life. It would also be appropriate to have the guidance, navigation, & control team work their way back through the design process to determine if there is a more efficient design that would reduce the weight of the UAV. There is a chance that the team could look for more guidance, navigation, and control components that are lightweight and efficient enough for the operation of the UAV. Since the team used off the shelf components, these components may have not been as lightweight as aerospace grade materials. As far as communication with the teams goes, it would be beneficial to determine whether the teams were using a requirements-based design process described by Howard Loewen (2013). UAV manufacturing processes can be incredibly complex and highly structured. “As the UAVs produced become more sophisticated ad-hoc design processes become insufficient. Presently, more UAV manufacturers than ever have come to realize structured design processes are essential if they intend to develop reliable products” (Loewen, 2013, pg. 1). A requirements-based design process is a thorough methodology that helps UAV manufacturers address concerns and issues during the designing process for UAVs.

            Since the marketing team has already been talking to customers about the spread of the fertilizer, it is important to consider how customers would react if the product did not spread fertilizer as well as the marketing team specified. The profits from the UAV could be incredibly limited if customers purchase the UAV and determine that it does not spread the fertilizer as efficiently as the marketing team specified. As the system engineer, I would recommend the payload delivery team go back to the early stages of the design process and determine if custom designed hardware would reduce the weight of the UAV. Keeping the customers happy is a critical component of the well-being of the business. If the customers believe the marketing team has lied, word will spread and fewer customers will come back to purchase the next generation of the UAV from the business. I would suggest that the payload team redesign the fertilizer delivery system. If the delivery system had a wider spread, the UAV would require fewer laps around a field while dispensing the fertilizer. With fewer laps over a field, flight times should be shorter and fuel should be conserved. With better fuel consumption, the safety engineers will be satisfied. If aerospace grade materials are used by the navigation, guidance, and control team, the weight of the UAV could be reduced.

Future prospects for the next generation of the system

            With the first generation being overweight, the second generation of the UAV cannot have the same design flaws. The teams must collaborate in a more efficient manner; using the requirements based design process should prevent problems from occurring like they have with the first generation. As the systems engineer, I will act as the “great decider” and ensure each design team is communicating with the other teams so the chance for miscommunication is limited. If each team communicates properly, every person will be able to weigh in on solutions to keep the UAV within design limitations. With the issue of the first generation being overweight, the designers of the next generation should increase the acceptable weight loads of the UAV. Custom designed hardware should be considered before using off the shelf hardware. Payload levels should be increased and the marketing team should collaborate with the design team to prevent any misleading information from being spread to potential customers. If the first generation cannot be redesigned to meet the needs of the customer, the price of the next generation could be adjusted as compensation for the first generation not being within specified design requirements. I would also suggest that the allotted budget for the UAV be increased if possible in order to compensate for the purchase of the required materials. 

References

Loewen , H. (2013). Requirements, based UAV design process explained. Retrieved from             https://www.micropilot.com/pdf/requirements-based-uav.pdf

Terwilliger, B., Burgess, S., Hernandez D. (2013). ASCI 530 unmanned systems: Global system   design concepts, requirements, and specifications overview [PowerPoint Slides].