{"id":10713,"date":"2025-09-15T20:25:05","date_gmt":"2025-09-15T19:25:05","guid":{"rendered":"https:\/\/dronesonen.usn.no\/?p=10713"},"modified":"2025-09-15T20:28:41","modified_gmt":"2025-09-15T19:28:41","slug":"hydrawlics-week-4","status":"publish","type":"post","link":"https:\/\/dronesonen.usn.no\/?p=10713","title":{"rendered":"Hydrawlics \u2013 Week 4"},"content":{"rendered":"\n
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Hello and welcome back!\ud83d\udc4b

In last week\u2019s post, we defined our Minimum Viable Product (MVP) and divided the main components into individual responsibilities. This week we have each been working on our parts to bring the MVP to life.<\/p>\n\n\n\n

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As a reminder, the tasks were distributed as follows:<\/p>\n\n\n\n

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  • Fredrik<\/strong> \u2013 Build the actuator system and prototype end effector
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  • Erling<\/strong> \u2013 Design a simple joint mechanism using syringe hydraulics
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  • Emory<\/strong> \u2013 Research and develop a proof-of-concept image edge detection algorithm in Python
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  • Lisa<\/strong> \u2013 Source parts and code the C++ Arduino firmware to demonstrate the motion of the hydraulic arm
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  • Syver<\/strong> \u2013 Implement a baseline Python Flask webserver for collecting and serving user content, serving as the system interface
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    In this post, we\u2019ll share our individual progress and results so far!
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    Fredrik<\/h3>\n\n\n\n

    This week I was responsible for the hydraulic actuator system. In other words, I need to push the syringe with the use of an electrical actuator. For this early development phase, I based the design on the components we had easily available, being mainly servo and stepper motor. The stepper motor can exert more power, but the servo has positional awareness. This positional awareness can come in handy for repeatable testing, so we went forward with the servo. <\/p>\n\n\n\n

    The system needed to convert rotational motion from the servo to linear motion. I brainstormed some concepts of systems that could accomplish this, shown in the images below. I landed on the last of these concepts. This is mainly because the rotational and linear motion is proportional, eliminating the need for solving this in software. Another benefit of this concept is its thin design, with everything being in one line. This would make it easy to stack the system for more syringes.

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    The sg90 servo can rotate approximately 180 degrees, and the syringe needs to be pushed 66.5mm. I used bevel gears to allow for more rotation in the system per degree from the servo, thereby reducing the linear transmission per degree. <\/p>\n\n\n\n

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    Every part of the system is 3D-printed on my 3D-printer, with the exception of the servo and the syringe. When designing and testing, I quickly understood that friction would become an obstacle. Therefor I played around with different 3D-printing materials, mainly PLA and PETG, and figured out that a PLA surface to a PETG surface had low amounts of friction. Many of the parts in the system is therefor printed with this in mind, trying to alternate between the two. <\/p>\n\n\n\n


    The finished system is shown in the images below. The system ended up successfully converting rotational motion from the servo into linear motion, with low friction and high precision. Although when attaching the syringe, the force exerted by the system fell short of the required amount, meaning that the syringe was not pushed and pulled in a way that would work in our project. This is shown in the video below. The system did however serve as an excellent proof of concept, and could be further developed into a fully working force transmission system. If I were to work on this concept moving forward, I would look for ways to reduce friction even more, switch to a stepper motor instead of the servo, and consider switching to a rack and pinion system. <\/p>\n\n\n\n

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