Wednesday, November 28, 2018

Presentation #3 Motor Controls Update (Pictures Below)

This week the controls team went over our final presentation of the year. We have made great strides through the semester. As of right now we have a working motor model prototype that can be found in our Presentation slides. This working model will allow us to found out how to attenuate the motors so they can communicate with one another and work in tandem as if a differential were driving the two motors. Each motor is a small drone BLDC motor that is operated by a potentiometer. This potentiometer value can be changed to change at what values the motor will run and at various speeds. As the potentiometer is turned to its max value, the motor runs at maximum speed. However as the speed grows higher, the noise frequency tends to become a bit high and unpleasant so I will consider capping it at a safe range to avoid unwanted frequency vibrations. Looking ahead towards the final weeks and next semester, there are still many things to be done. Going forward there is the need to fix the motor model and make sure the wires are safely placed to avoid unwanted arcing or shorts. Increasing the modularity of the motor model will help us later on when the actually bogie motors come in and we will be able to transfer the code and concepts from the small prototype model the full scale model with little needs for adjustment. Continuous changes such as updating the motors with encoders to be able to calculate the speed of each motor, adding resistors to make the motors spin slower at certain moments, and separating our power leads from the rest of the circuit to avoid any damage. The next step is to run two of the motors simultaneously with one battery source in order to mimic the full scale model as closely as possible. Each axle on the bogie will probably have one ultra capacitor cell attached to it and being able to get the current to the motor with the least amount of resistance will help keep the current high with minimal voltage and current drop over time when the bogie will have to go about 10 meters of track before recharging again so keeping current high and stable is a key insight that the team must attend to with wayside power to make sure the motors are constantly working. If the motors were to stall in the middle of a trip, it may spew disaster as another car may crash into it or the person could be stuck on a floating island for a few hours before rescue workers can clear the line and rescue the person in immediate danger. Many more safety factors and prototyping has to be done before moving on to the finished product so we avoid as many setbacks as we can on the real motor and motor controllers.
The motor model can be found below. A few immediate modifications is to add fuses to avoid and shorting or frying of the equipment.

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