Students are challenged every year with a unique project during their placement year with CFMS, which allows them to explore different areas of engineering including Model Based Engineering and simulation. In this project, our interns were challenged to design and manufacture an autonomous surveillance platform using Model Based Engineering (MBE).
MBE is the basis of digital thread and helps to facilitate informed decisions by connection key requirements with processes; it also forms the basis of digital twin technology.
An autonomous surveillance platform weighed less than 250 grams and included a payload of 50 grams was required to be built using Model Based Engineering. Other key requirements included being able to fit the platform into a 30-litre rucksack, for it to autonomously traverse and survey a perimeter of 350 metres, and to be able to fly for 10 minutes continuously.
The first stage of the project was to explore the different types of designs for the surveillance platform. Following research and investigations into the different platforms, it was established that the multicopter design was the most suitable solution due to its stability and manoeuvrability.
Using CFMS’ in-house simulation framework, different multicopter variants such as tricopters, quadcopters and hexacopters were compared against the customer’s requirements. The results suggested that the tricopter with a balsa framework with nylon fasteners was the best solution for the project.
A plan for the manufacturing of the tricopter was generated and based on the assigned timescales, it was estimated that the process would take 26 working days to complete.
During the trial stages some issues arouse. At higher throttles, the tail experienced vibration, throwing the system off balance. To overcome this, 3D modelling was used to try and resolve some of the instability problems. An improvement of the initial model was proposed where the rigid body dynamics of the full system would be remodelled. Using CFMS’ in-house simulation framework the model was redesigned. The simple flight controller and radio were incorporated with the improved propulsion system to create a quadcopter model.
The 3D modelling of the design helped to improve the design of the surveillance platform and overcome the issues that were established during the test flight. Continuing future work on the project could improve the design of the model. This includes the use of an Ardupolot Interface, which could be used to update the dynamics model written in Python and would be required for the development of the digital twin. The flight trials also highlighted the importance of analysing the structural integrity of the system and carrying out a vibrational analysis to design the framework better.