Blog Posts

Gator Waves – Week of Apr. 18th

Gator Waves at the end of FDR!

The final week of IPPD has arrived for Gator Waves! An unexpected issue (misplaced glue) in a mechanical part of the design caused unexpected test results, but this was ultimately resolved. Test data was able to be collected regarding a stress wave turning around a single bend. Unfortunately, test data regarding the constructive interference of stress waves was not able to be collected because the timing of 50 μs was not achieved. Still the final design is able to fire two striker rods simultaneously and measure the stress wave propagation at multiple points in the system. 

A closer look at the FDR poster

At the FDR event held on Tuesday, April 19th, our team presented what we were able to achieve this semester and also demoed the design for FDR attendees. The electrical engineers plan to spend a few more days attempting to achieve the 50 μs timing, and the team will make adjustments to the FDR report based on feedback from our liaison, Dr. Subhash. Even though all objectives of the project were not able to be achieved, our team has learned a great deal in the process and appreciates the experience IPPD has provided. Thank you!

The Gator Waves FDR video!

Gator Waves – Week of Apr. 11th

An image of the assembled PCB for the instrumentation amplifiers

Gator Waves used this week to continue preparing for FDR (Final Design Review) and developing the final design. The team worked on completing the rough draft of the FDR report, as well as getting peer feedback on a practice FDR presentation. Also, the poster design was finalized and sent to IPPD for printing.

The mechanical engineers spent the week adhering additional strain gauges to key parts of the design in order to better characterize stress wave propagation in the system. Also, they completed manufacturing all the necessary components and finalized the alignment of the assembly.

The electrical engineers continued to work on characterizing the timing of the controller. After collecting data of repeated test runs measuring the time when the striker rod impacts the incident bar, it was determined that a timing repeatability within 177 μs has been achieved with the current iteration. Moving forward, adjustments will continue to be made until the desired 50 μs is ultimately achieved. Also, the PCBs arrived earlier than expected, so those were assembled and tested!

Gator Waves – Week of Apr. 4th

The PCB design for the current drivers (and DACs)

With FDR (Final Design Review) coming up soon, Gator Waves spent this week continuing to make progress towards completing the project. The PCB layouts for the current drivers and instrumentation amplifiers were finalized and ordered. Unfortunately, the expected delivery date is listed as April 19th, which is the day of FDR, but fingers are crossed for an early delivery. Nevertheless, back up plans have been devised in case they do not arrive in time for the event.

An image showing the controller at work (the blue channel is the output of the DAC and the yellow channel is the strain gauge reading). The strike occurs at the large spike in the yellow channel

The electrical engineers have also moved forward with characterizing the timing of their current controller. Because the final assembly is still being finalized by the mechanical engineers, the timing is being measured using a single striker rod and incident bar. The controller is tuned by monitoring the output of the position sensor (magnetic encoder), verifying the SPI communication to the DAC, and comparing what is observed to MATLAB and ModelSim simulations. Also, one of the magnetic encoders was broken this week, so moving forward the design will feature two striker rods rather than three.

The mechanical engineers spent the week finishing the manufacturing of z-brackets for holding the specialized incident bar, as well as adjusting the alignment of the striker rods with the aluminum spacers. Also, the team worked on the first draft of the poster for FDR.

Gator Waves – Week of Mar. 28th

This image may look similar to last week’s, but there are a few key changes that have made a huge difference!

This week, Gator Waves continued working towards the completion of the final design. The mechanical engineers helped with repairing a broken solenoid, as well as protecting the fragile wires of the shielded cable by applying a glue coating. They also spent some time machining brackets.

The Wheatstone bridge and instrumentation amplifier setup, now including a low pass filter between them!

The electrical engineers focused on debugging a number of issues that arose while using the full electronic set-up with the power supply. Some of the problems included issues with the strain gauge wires and radio-frequency interference with the instrumentation amplifier. By isolating different parts of the system, consulting experts in the ECE department, and researching high frequency interference, it was determined that a low-pass filter was necessary for the correct operation of the instrumentation amplifier.

Strain gauge with a shielded cable

Also, the strain gauge wires have been replaced with shielded cables, which has improved the clarity of the signal. With these issues now taken care of, the team is ready to verify and order the PCB and begin tuning the timing of the controller once the final housing is done.

Gator Waves – Week of Mar. 21st

The testing set up for the controller and single striker rod

Gator Waves began this week by preparing for Prototype Inspection Day, which was Tuesday, March 22. On Monday, the electrical engineers were able to debug the issue with the DAC and FPGA connections so that the striker rod could be fired using the FPGA. This was showcased at PID, along with the work the mechanical engineers have completed so far in manufacturing the final assembly. Feedback from the judges of the event was mainly positive, with some requests to include MATLAB simulations in the appendix of our presentation, as well as to discuss real-world applications.

Moving on from the event, the mechanical engineers spent the week manufacturing the base plate, getting more solenoid covers 3D printed, and ordering four additional linear rails for the final design. Next week, they will focus on completing the z-brackets and solenoid bases, 3D printing the remaining sensor mounts, and assembling the available components. The electrical engineers worked on testing the controller with the moving striker rod, continuing work on the PCBs, and integrating the power supply with the final design. On Friday, the controller was finally debugged to the point that it properly responded to the position input from the encoder. Moving forward, focus will be shifted to fine-tuning the controller, testing the power supply with an LDO, and getting the PCBs ordered.

Gator Waves – Week of Mar. 14th

Marissa machining the aluminum baseplates

With preparations for Prototype Inspection Day underway, our team was busy this week picking up from where things left off before spring break. The mechanical engineers manufactured aluminum baseplates for the bronze bushings, wound the middle solenoid, and finalized the base plate design for the CNC machine. Next week, they will proceed with finishing up the remaining manufacturing.

The simultaneous firing of three solenoids, including the newly wound middle solenoid

Regarding the electrical side, the current driver and instrumentation amplifier portions of the final PCB were designed. The entire layout will be completed and ordered by some time next week. Also, the simultaneous firing of three striker rods was tested with the power supply.

The most recent iteration of the final PCB design

Additionally, the full controller was tested with the DAC (with the striker rod in a fixed position), and debugging of the code was completed in order to be able to test with the current driver and encoder. However, some unpredictable behavior has been observed with the connections between the DAC and FPGA, and so a new perfboard has been soldered by Ian for testing. The team hopes to collect timing data on the full controller implementation before Prototype Inspection Day on Tuesday of next week.

Gator Waves – Week of Feb. 28th

Ian tested the current driver circuit with the power supply

This week, Gator Waves continued moving forward with the project in preparation for the upcoming Prototype Inspection Day. The electrical engineers worked on testing the DAC with the SPI module that has been implemented on the FPGA. Also, last week an updated version of the transfer function was determined. This week, it was implemented in VHDL using fixed point operations. A top level design was written for implementing the entire controller on the FPGA, which will be tested and adjusted over the next couple of weeks. Also, incorporation of the power supply in the overall system has begun.

Additionally, the team met with Dr. Subhash to discuss some mechanical design changes as well as a budget increase. The mechanical engineers worked on reprinting the new version of the sensor mount and printing a middle solenoid casing. Next week is spring break, and so the team will be slowing things down to enjoy some time off. Still, the electrical engineers plan to put in a few hours testing the top level design and incorporating the power supply.

Gator Waves – Week of Feb. 21st

Investigating the SPI module clock signal (SCLK) at high frequencies

Gator Waves spent this week participating in the QRB 2 event, as well as making progress on implementing the final prototype design. On Monday, the team met with Dr. Subhash to discuss the work completed last week, as well as plan for the additional meeting in the IPPD lab on Thursday February 24th. The QRB 2 event was held on Tuesday, and our team presented the current status of the project and our plans moving forward to ensure its completion. We received feedback from a committee of team coaches, which was mainly positive. There were also suggestions for improvements in the testing plan, which are now incorporated in our timeline.

On Thursday, Gator Waves met with Dr. Subhash in the IPPD lab to present our progress in person and demonstrate the current prototype. During this meeting we received important feedback that has influenced our plans for the weeks to come. After the meeting, the mechanical engineers worked on iterating through designs of the bushings. The electrical engineers continued work on the SPI module, and after consulting an ECE staff member, became aware of RF (radio frequency) complications due to the 50 MHz operation. Also, an improved version of the transfer function has been determined.

Next week, the mechanical engineers plan to machine the bronze rods for the aluminum bushings, as well as machine the aluminum rods. The electrical engineers plan to test the finished SPI module with the DAC and investigate ways to mitigate the RF complications, as well as implement the updated transfer function in VHDL.

Gator Waves – Week of Feb. 14th

Testing the transfer function for the control system required outputting the calculations to the 7-segment displays. Pictured here is the final (and correct) value

Gator Waves spent this past week continuing adjustments to the prototype. The mechanical engineers worked on modifying the starting position of the striker rod to be more reliable so that measurements of the rod’s position using the incremental encoder can be consistent. Also, three strain gauges were attached to the final design of the incident bar. Next week, the mechanicals will be machining and assembling bushings, a base plate, and an alignment plate.

Adjustments were also made to the implementation of the decoder in the FPGA in order to resolve an issue with increasing offsets in the position measurement, which arose this week during testing. Furthermore, the electrical engineers worked on implementing the reference signal in memory, setting up four additional instrumentation amplifiers, and verifying the transfer function VHDL code. Moving forward into next week, focus will be placed on finalizing the SPI module and also being able to measure stress waves at all points in the final design of the incident bar. Additionally, the team is preparing materials and a presentation for QRB 2, which will be held on Tuesday, February 22nd.

Gator Waves – Week of Feb. 7th

The board and FPGA used for testing the SPI module (and previously the counter output, hence all the extra wires)

This week, Gator Waves continued to make steady progress on the project. The electrical engineers focused on the control system FPGA code and testing. This involved determining the VHDL implementation for the transfer function that will generate the necessary outputs for the current driver. It also included continuing work on the SPI module, with adjustments made for it to run at 50 MHz. Further developments still need to be made to the SPI module regarding the clock signal output to the DAC, and next week focus will also be placed on writing an Avalon memory mapped interface to request data from the flash memory in the FPGA.

The mechanical engineers worked on designing and developing the electrical bay and mounting system for the PCB, which will need to be implemented in the final iteration of the prototype. The middle solenoid design was sent to be 3D printed, and it will be wound and tested next week. Also, next week the mechanical engineers plan to water jet aluminum rods from the base plate and machine the solenoid base as well.