Author: anmills

This week, I focused on the design report. I finalized all aspects of communication and physical connections between all hardware components on the robot. I also roughly laid out where all hardware components will be on the robot in the robot’s block diagram. I redid all calculations for numbers in the design report, and I rechecked these numbers with my previous work I used in the design presentation.

Due to the robot car kit, Teensy 4.1 microcontroller, and H-Bridges being ordered last week and the following week being a break, I am behind. This upcoming week, I plan on working extra hard to finish assembling the robot car kit and finishing the core programming of the robot. This includes the communication between the Teensy 4.1 and Raspberry Pi (UART communication) and the naive movement of the wheels (PWM module). I plan on pushing the encoder module and PID control back a week since it isn’t a part of the key functionality of the robot car. Pushing these modules back a week ensures that Rose and Elly can work on their parts without falling behind due to my error.

This week, I set up the Raspberry Pi 5. We realized the Raspberry Pi 5 kit we got didn’t include a micro SD card, so I placed an order for one, but in the meantime, I borrowed a friend’s micro SD card. Since the Raspberry Pi 5 doesn’t naturally support VS Code, I looked into remote-SSHing into the Raspberry Pi 5 to upload code and got that system working. Since I am mostly waiting on parts to arrive to continue working, I also looked more into the compatibility of other parts and more about the Teensy 4.1 firmware/manual pages. Due to the majority of my work needing to be done next week, I tried to offload some of the work by looking into any potential issues I might face ahead of time. I also presented the Design Presentation to the class and reviewed the feedback from the Q&A section we received. 

Since this week is mostly dedicated to early software development and the Design Presentation, the hardware/firmware section I am working on is still on track for the project schedule.

Next week, I hope to build the basics for the robot car kit. I also hope to get the motors to start moving so that the car can move forward and backward, and potentially side to side or turning.

I worked on picking out the specific hardware components for this project. This included the robot chassis, wheels, motors + encoders, H-bridges, transformer/buck convertor, and power supply. 

For the robot chassis, I looked into kits that could support 30 lbs of load, but unfortunately, none of them would come promptly. I had to compromise and picked a chassis that can hold 22 lbs, and I am planning on reinforcing the chassis and axles if needed. The robot kit I settled on includes 4 omni wheels and motors with encoders.

When deciding the motor used, I also looked into the motor’s torque and rpm and did calculations to ensure the max speed can reach 4 mph (calculated using the robot kit’s wheel diameters and motor’s rpm) and that the torque of the motor should be greater than ~3N of force (calculated using the max load of groceries). I found some motors that fit this specification, but since the robot kit includes motors and the new motors have other factors to consider – such as how to attach them to the robot (which motor brackets) and axles (differing axle sizes), and if the H-bridge can power them safely – I decided not to immediately order them. Instead, I am planning on testing the initial PID and motor movement using the motors given in the kit and upgrading to the new motors once I figure out the solutions to this problem. 

As previously mentioned, I researched H-bridges to power the motors. I had to ensure they could safely handle a peak of 28A if the motors from the robot kit stalled.

My progress is on track this week. Since I can test the robot’s motor control and PID with the motors given in the kit and upgrade to better motors later, I am still on track.

Next week, I will be doing the design presentation. I will also be looking more into the motor issue and hopefully solving that by the end of the week.

I worked on selecting the microcontrollers that will control the motors and host the software side of the project, including the web app and LiDAR mapping. During this research, I gained a deeper understanding of the various specifications and performance capabilities that microcontrollers are designed to handle. I ensured that the microcontrollers I selected would meet the sensor and computational requirements of the project. I decided on using the Teensy 4.1 for the low-level motors and encoders, since it supports real-time feedback and low latency. I also decided on the Raspberry Pi 4 for the more computationally expensive and less time-critical tasks, such as the LiDAR mapping, obstacle detection algorithms, and web app.

According to the Gantt Chart, I am still on track to meet the fully fleshed-out hardware aspect of the design report in roughly two weeks.

Next week, I hope to pick out the specific sensors, such as the motors + wheel diameter, LiDAR sensor, etc. I will look at multiple industry standard options, weighing things like compatibility, cost, and torque, to determine which ones best meet the requirements of this project.