This week I worked with Deepak on the STM32 timers to trigger the ADC. We verified that indeed PWM was working and decided that we have to use one timer to triggeer another. Timer synchronization is more difficult than we thought, as we are using one timer to trigger another, and the second one has to start at the exact same time to be able to trigger the ADC. We had to fiddle around with the prescaler of the timer…
This week I worked on getting the timers to trigger the ADC. The ADC must be triggered at a specific time in the PWM cycle, so naturally I first tried to generate the trigger from the timer generating the PWM. When I got the ADC triggering properly and data coming over UART, there seemed to be no PWM output. I confirmed this with an oscilloscope, and experimented until I realized I could not get the PWM and ADC triggering to…
This week we primarily worked on the Design Review Report, and also got a basic graphing interface, known as ROTATÉ, working to show live motor data in a more useful way. Working on the Design Review Report was useful in that it made us think in more detail about what we are doing and why, giving us a clearer understanding of where we are in the semester. We are also moving into getting a clearer understanding of motor control theory beyond…
This week I spent a lot of time practicing for the Design Review presentation and working on the Design Review Report. The Design Review presentation went fairly well based on the feedback. The next major thing I did as I was writing the Report was reviewing the basics of motor operation. In order to describe the differences between brushed DC motors and 3-phase brushless motors as part of the Report, I found a good source that described the basic operation…
This week I worked on the Design Review Report and prepare for the Design Review Presentation. The report involves doing a lot more background research into the further mathematical details of Field Oriented Control theory. I also contributed to writing the abstract, introduction, architecture/principle of operation, and the project management sections of the report. I spent some time looking into tabletop motor dynos, which looks like it might be possible if we find two motors and bind their output shafts…
I have brought ROTATÉ into this world. ROTATÉ is a python utility that allows us to visualize and process the data from the JANKTROLLER in real time, which will be indispensable for tuning control loops and validating sensors. It isn’t pretty, but it gets the job done, and the underlying data passing system allows us to easily add messages and make logs. It is also fairly fault tolerant, as a delimiter or message tag gets dropped every now and then. In addition…
This week I worked with Deepak on figuring out the UART and DMA firmware that we are putting to test on Janktroller++. We found out that the gate driver on Janktroller has some built in deadtime, which we are using in addition to the deadtime we are setting in software, which initially was confusing but now makes more sense. Getting live UART data from the board meant that we were able to get live diagnostic data to better understand what…
This week we were able to get the motor spinning slowly. This involved a number of different things. The first one was bringup of the microcontroller’s timer to output PWM. Another accomplishment this week was writing a rudimentary control loop to spin the motor. We were also able to send information about the voltages and currents over UART. Overall, the motor spinning validates our basic hardware architecture, and we are confident in moving forward both with further firmware development, and…
This week I got the STM32’s PWM working and set it properly. This means making the PWM center-aligned, rather than edge-aligned, and inserting dead time as described in last week’s blog post. The PWM works fine, and Bolaji was able to use it to get the motor slowly spinning. The next thing I worked on was getting UART to work. It was fairly easy to set up in blocking mode, but it ended up causing a problem. The amount of…
This week, I adapted the PWM driver to take duty cycles for each phase and then ported the simulation stuff to the janktroller and it spun the motor. It was very good because it proved that all of the power controls and stuff works and gave us a baseline to start looking at ADC readings, but also very bad because we haven’t brought up the ADCs yet so it was entirely “dumb” control. Being able to make the motor move…