My final year Mechanical Engineering capstone project involved designing, testing, and building a proof-of-concept Pan-Tilt-Zoom (PTZ) Inspection Camera Unit (ICU) for implementation in the nuclear industry. The project was completed in coordination with Laveer Engineering, the project sponsor. The intended use of the device was to support the maintenance of Canada Deuterium Uranium (CANDU) reactor boiler refurbishment. The ICU was designed to serve as an overview system for tracking remotely controlled tools in the boiler as they completed work series. The ICU was designed to be capable of continuous 360-degree rotation in the pan and tilt directions and consisted of a fully enclosed, dust and water-proof housing. The device was capable of mounting on curved steel surfaces using magnetic feet. The camera module was selected to meet the design requirements of having 10x optical zoom and a 1080p video quality, to ensure the operator could easily monitor the maintenance tools.

The ICU had several functionality requirements. The unit had to be capable of operating in a low radiation environment, which meant that load-bearing members had to be metal. The ICU body had to limit exposed cracks and crevices to prevent contamination and water from entering the ICU body when operated in a damp environment. The system needed to be capable of both autonomous tool tracking and manual control. The unit had to be powered by a Power over Ethernet (PoE) cable, which could connect to a laptop where the video feed would play. The environment in which the ICU operates is dark, so the ICU had to incorporate a variable onboard light source and a laser. Weight and durability considerations were taken to ensure ease of installation and removal and longevity of the device. The exploded view of the final design of the ICU can be seen in the figure above. The main complexities of the design were driven by the requirements for water resistance, continuous rotation in pan and tilt, back-drivability, tight packaging and low weight.

The team met the requirement for water resistance by implementing O-rings and a custom convolution seal to prevent water ingress in the main ICU body. Continuous rotation was achieved with the implementation of slip rings on both driven axis. The slip rings played a major role in driving the selection of gears and the layout of the ICU body. Pan back drivability was achieved through the development of a custom friction clutch. Tilt-back drivability was achieved with the selection of a low gear ratio with a close inertia ratio between output and motor rotor. The team was able to meet the tight packaging requirement by implementing a custom light ring for the ICU head, and small clearances between internal components. The final design was 13cm x 19cm x 16cm with a mass of 3.7 kg, meeting all the space and weight requirements.

The team first developed a printed prototype for functionality testing, to optimize the electrical layout and the mechanical design. After completing assembly and testing on the convolution seal and pan and tilt motors, I created formal manufacturing drawings for machining. The final proof of concept included both printed and machined parts. Several parts with critical dimensions were machined by the team in the university machine shops.

My major role in this project was systems lead and mechanical designer. The systems lead role involved coordinating with Laveer and the capstone supervisor, creating timelines, assigning roles, reviewing the budget and setting meetings. I also played a major role in brainstorming and reviewing the design of the control systems, electronic layout, and image processing. As the mechanical designer, I was responsible for developing the design of the ICU head, body, base and center post. The design of these components included bearing selection, motor and driver selection, load calculations, and ANSYS Steady State thermal model generation to optimize the internal heat distribution.