The only part left to pick was the line sensors. It is also small and uses a Micro-B USB connection for programming. This Arduino-compatible programmable controller is based on the ATmega32U4 from Atmel and has an onboard switching step-up/step-down regulator that allows it to be powered efficiently from 2.7 V to 11.8 V. For my main microcontroller, I used the A-Star 32U4 Mini LV. Since the Qik accepts serial commands and has an Arduino library, it was easy to integrate into my system. The Qik 2s9v1 Dual Serial Motor Controller fit these criteria and worked great with the motors I chose. I wanted a small dual motor driver that did not use a lot of I/O pins to drive from a microcontroller. I used the speed of a 3pi robot, which is roughly 1m/s, as a base-line goal to beat. After some quick calculations, I determined the 70 mm wheels should give my robot a theoretical maximum free-run speed of around 2 m/s. I also used a lightweight 3/8″ plastic ball caster as a third contact point. Also, the 3mm-diameter D-shaped output shaft is compatible with our Pololu Wheels. These motors have a free-run speed of about 575 RPM at 7.5V and plenty of torque for my lightweight robot. I used a pair of our 35:1 Metal Gearmotors 15.5Dx30L mm and compatible mounting brackets. I also had an extra 3S LiPo battery that I decided to use as my main power source. I ended up choosing the 7.5 V D24V25F7 regulator because it fit well with the rest of my system. I chose to use a regulator from the D24V25Fx family of step-down regulators, which allow for output current of around 2.5 A and come in a variety of output voltages from 3.3 V to 9 V. A great way to prevent this inconsistency is to use a voltage regulator. when the batteries are recharged or drained). When designing a line following robot, one thing to keep in mind is that the performance can change significantly when your battery voltage changes (e.g. The first thing I decided was how I was going to power The Chariot. In other words, my hope is that after reading through this post, it will be clear why I chose the parts that I did. Instead of focusing this blog post on how you can make your own version of The Chariot, I will try to explain my thought process throughout the design and build process. The Chariot ended up winning second place in the competition, which I was very happy with. After brainstorming a few ideas, I ended up deciding to keep it simple and make sure I had enough time to get a robot I was happy with, which I ultimately named “The Chariot” because of its shape. I also remembered spending so much time designing and assembling the hardware for my last line following robot, that I ended up not having enough time to tune the PID coefficients and get the performance I was hoping for. However, I knew the winning robot from the last LVBots line following competition (Mostly Red Racer) would be returning, and it had an impressive time to beat. For the recent LVBots line following competition, my first instinct was to try to come up with some unique alternative design for a robot that would be competitive with the traditional differential drive robots.
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