Personal tasks of this week:
Task: Literature Review
Definition: By studying Sergey’s Thesis more closely, our aim was to look for methods in which we can further flesh out or improve our design.
Completion: The task is completed. By taking a closer look at the thesis, we were able to discover the primary accuracy and performance concerns of the system. These are the nonlinearity of the potentiometers contributing to a decrease in accuracy, as well as the negligence of parasitic capacitance contributing to a decrease in performance. More specifically, in Sergey’s PCB design, due to an oversight in the parasitic capacitance, it caused his system to develop non-stable behavior, which required him to add compensating capacitors to the feedback loop of his op-amps. If these were considered, the step response could have been significantly improved as shown below. By learning from mistakes in the original designs like these, we believe that we will be able to achieve solid performance. Furthermore, this research was very helpful in determining which component aspect we should put the most focus on.
Source: https://www.sciencedirect.com/science/article/abs/pii/S0098135414000131
Task: Spice Selection
Definition: To begin circuit simulation, a spice tool would be required to test the behavior of our preliminary circuits. Considering the wide variety of spice tools available, a detailed review of each of the available products was done.
Completion: The task was completed. We have decided on using Cadence’s PSpice considering its performance, as well as the fact that it is readily available to CMU students. The contender was AltiumSpice, as our PCB design will be in Altium, so it would be easy to integrate. However, we decided against it considering its performance.
Task: Preliminary Part Selection
Definition: Considering our current requirements, a preliminary selection of our main components was needed to determine if we would be able to deliver the desired performance with the required performance and accuracy.
Completion: The task is partially completed. By using the same components that Sergey used as a baseline, we looked for components that had tolerances and performance that was at least as good, or better. Considering the developments in the industry, we were able to make a shortlist of parts that we are considering, but have not determined the specific components we are using yet.
Overall progress assessment:
My progress is on-schedule, as all of my tasks this week have been completed. I will continue working towards completing my Prototype of creating a circuit simulation of a simple optimization problem.