Author: seungyul

This week, I worked on the ethics assignment and finishing up the aiming system prototype.

I’ve adjusted the mounting point for the vertical aiming system’s arm, which was further away from the previous version, making it more stable and easier to screw in. The servo motor house’s mounting point has also been re-printed and everything was assembled nicely.

As I was about to work on the electrical connections, I’ve realized that I don’t have the appropriate wires. For the servo motor, the three wires coming out of it are all lumped in a female dupont connector, and the stepper motor has bare cables coming out of it. I’ve ordered dupont cables and block connectors so I can make all the wired connections come together.

I am still on schedule according to the Gantt chart.

For next week, I will be making a final push so that the aiming systems all come together. While I wait for the new parts to come in, I will be working on enhancing the prototype so the vertical and radial aiming systems are connected, as well as the base for the robot. Once I have the parts, I will be writing control modules for each system so I can demo that in the following week.

The past two weeks (but mostly week before this), I’ve continued on iterating on the vertical aiming system and the radial aiming system. I’ve also worked on writing the design review report that was due last week.

For the radial aiming system, I’ve laser cut a new plate that is compatible with the flange coupler, and attached them all together. There are few more details to flesh out such as finding the right screws (I’ve been using the spare ones in TechSpark so far) and not messing up the actual cutting so it’s round, but the prototype feels stable.

For the vertical aiming system, I’ve made some mistake in CADing it so the house for the servo motor didn’t come out well, but the arm in which the barrel will sit came out nicely. Similar to the radial aiming I still need to find the right screws to attach the arm to the servo motor in a correctly aligned manner.

I am still on schedule according to the Gantt chart.

For next week, I will start connecting the radial aiming systems’ electronics, and write some primitive control module on the Pi. For the vertical aiming, I will re-print the servo house, and finalize the physical structure. I will also slowly start thinking about how to integrate both systems.

P.S. I went to a museum during spring break and found something that could be an alternative vertical aiming system design.

This week, I worked on practicing for Design Presentation (and actually delivering), and working on the construction of the radial aiming system. The stepper motor was delivered early this week, so I took some time to iterate on the prototype to think about the actual connections of the individual laser-cut components, and how to attach the base to the shaft of the motor.

The stepper motor house came out nicely – I am a little worried about the flatness of the motor, so I will probably end up adding a bottom plate for the motor house. The lazy susan plate poses a bigger mechanical challenge as it doesn’t fit very tightly to the shaft. To mitigate this, I’ve ordered a Flange Coupler, which will be fastened onto the shaft, and the next version of the plate will have holes cut into it so that it can attach with the flat part of the coupler.

While trying to test driving the motor, I’ve realized I need a stepper motor driver (DRV8825) on top of the motor to actually interface with it, and also to protect the hardware from current surge – I’ve ordered stepper motor driver this week so I can start trying to control it on the Pi.

My schedule is still on track as this week and next week is building the first version of the vertical and radial aiming system and finding out what problems I might encounter, as I have done this week.

Next week should be relatively busy with the Design Report, along with additional parts such as the ones I’ve ordered this week and the servo motor should be delivered. I aim to deliver vertical aiming system’s prototype and finalize the radial aiming system’s mechanical portions.

This week, I finalized prototyping the vertical and radial aiming system in SolidWorks. Attached are the rendered images of the prototype.

In addition to prototyping, I’ve placed the order for the motors needed for each system. For the radial aiming, we’re using this motor, and for the vertical aiming, we’re using this servo motor. Both motors were selected based on high torque it provides. The radial aiming system is the same as the design that we originally had, but the vertical aiming was completely redesigned after our meeting with Prof. Fedder – the design that uses servo aligns with our design goals or precise angular control more closely, while also achieving it at a much lower cost (the linear actuator with long range was around $100, while this servo motor is only $15).

Moreover, I will be presenting for our team for next week’s design presentation, so I’ve been working on absorbing the design details of the other subsystems of our project, and have been practicing my presentation as well.

I am still on schedule. The goal was to finish prototyping this week and start construction of both systems next week, so once all the parts are delivered, I will start laser cutting individual parts and assembling them to see if they work as intended.

For next week, I plan on constructing at least one of the subsystem’s prototype and see if they work as intended. If it doesn’t I will have to iterate on different design.

This week, I focused on prototyping the vertical aiming system and the radial aiming system. The feedback we got from the proposal presentation didn’t have major concerns with the mechanical portion of the design, so I started designing on Solidworks. We plan to build the robot’s scaffold to be laser cut from a 3/16″ thickness hardboard.

During the design, I’ve noticed that I would need the dimensions of the motors as a baseline, so I’ve also done some research on the parts we will use. For the radial aiming system, we’d need a stepper motor. The parameters that’s relevant for the purpose of radial aiming is low step angle for precise control, and high torque as lots of weight will be on the lazy susan base. The price has to be reasonable, and the speed of the motor is not relevant for our purpose. We came across this motor that meets the requirements, so we plan on placing the order for this part soon.

The the vertical aiming, we are still debating between using a linear actuator or using another stepper motor and using a string to coil to control the PVC pipe. We plan on fleshing out this design sometime next week as we prepare for the design proposal presentation, and order the necessary parts.

We are ahead of the schedule according to the Gantt chart, and by next week I plan to have a fully fleshed-out Solidworks design and have all the necessary parts ordered.