Electrical Progress Report: March 2019

The electrical team has seen tremendous progress in areas of the high voltage system, including battery management system (BMS), the batteries themselves, and the charging mechanism for Renatus. We have successfully connected and programmed the battery management system along with optimizing its capabilities for our own designed battery pack. Wiring instructions for implementing it into the car have been completed, along with verification that all the battery cells are at their optimal storage voltage. The electrical and programming team have also successfully interfaced the BMS with the controller area network bus (CANBUS) network of the central processing unit of the car. With this communication network we are able to collect data from the BMS and have a real time battery monitoring driver interface within the car. More recently the electrical team has looked into many possible charging solutions for the batteries including multiple low voltage chargers, one very high voltage charger, and designing a charger from scratch to interface with the BMS better. On to news about the future car, the electrical team has begun to outline some design considerations they want to include in the car. As well as outlining the design criteria, aka things that the car needs to have in order to be successful. All in all the electrical team is making progress on the vital systems that will enable Renatus to perform exceptionally well.

Emilio Sison and Nicholas Gildenhuys testing the battery management system (BMS).

Emilio Sison and Nicholas Gildenhuys testing the battery management system (BMS).

Spring 2018 Update

In order to charge the car more efficiently during the cross-country race, our team has begun designing and constructing a charging stand to hold the car's upper body. During rest stops, the upper body will be placed on the stand and rotated to provide more incident light on the solar cells, charging the batteries faster.

The steering wheel and column for Renatus have undergone multiple iterations since our last update. Members of our mechanical team have been prototyping possible shapes for the steering wheel based on the design of Celeritas' steering wheel. The steering column has undergone some redesigns, in order to better accommodate egress procedures. Our team considered the possibility of a pivoting steering column that could be pushed to the side in order to remove it from the egress path. The telescoping rod system we originally chose, where the steering wheel can be removed entirely by the driver so they can exit the car more easily, had to be reconsidered. Such a design would not have allowed wiring to go through the steering column, and our team has instead chosen a quick-release system to aid in egress.

Due to the width of our car and the height limit on our drivers, they will need to step on the upper body in order to enter or exit the cockpit. Since the solar cells are still fragile even after being encapsulated, we will need to either harden some of them further or remove them from the ingress/egress path entirely. 

The team discussing egress procedures and steering wheel design

The team discussing egress procedures and steering wheel design

As of our last update, our electrical team has been able to encapsulate and tab almost all cells needed for the car. Once the last five cells have been completed, we will begin producing additional cells to serve as backups during the cross-country race, so they can be used to replace any that might get damaged.

The braking team has made significant progress in the design of both the normal and emergency brakes. The hydraulic brake line design has been finalized and almost all the rotors, calipers, and master cylinders have been identified for the normal system. In addition, designs for the emergency brake have been completed, with the calipers and handles for that system already found.

The design team has worked extensively on redesigning the suspension, while performing interim finite element analyses to ensure the changes benefit the system's integrity. The upright and A-arm have been redesigned and fine-tuned in order to bring the maximum possible stress on them below the strength limit of aluminum. By doing this, we can reduce the overall weight of the car and free up weight for other systems.

In order to protect the driver in the event of a crash, we've begun looking at different types of foam to supplement the crumple zones in our car. The energy calculations for crashes at varying speeds have been performed, and our team is currently in contact with General Plastics to acquire foam that meets our specifications.

Our programming team has made significant progress on the Raspberry Pis and driver interface. They have been able to program a interim touchscreen interface for the driver, which will allow them to view data over various parts of the car. Additionally, they've begun programming the AI for the car and creating a method to input testing data, in order to see how the car's programming would react to conditions we meet on the road.

Weekly News - October 21st, 2017

The mock chassis is almost complete now that we have finished molding the mock PVC roll cage. Our mock canopy is currently drying and will be ready to use for practicing egress procedures by next week. The remaining pieces to complete are the seat, steering, and wheels for the mock chassis. In building the mock chassis, we’ve found that utilizing a telescoping rod for the steering column will make it easier to stow away than our previous plan, which necessitated the removal of the steering column from the car in order to exit.

Along with this, we discovered some grooves in our female windshield mold caused by wrinkling on the peel-ply we used during its creation. These have now been filled in and are going to be sanded down once again to level out and smooth the patches.

We’ve made good progress on designing the brake system for Renatus. The largest challenge we faced was sourcing out brake calipers. These needed to fit in our car and meet both our car specifications and race regulations. However, we were able to find appropriate calipers and are progressing further in our design. Our remaining tasks are to design a master cylinder head, a rotor for the calipers we’ve found, and draw up a brake line design.

Catching Up on Renatus' Progress

Over the past year and a half, significant progress has been made on various parts of Renatus. This includes redesigning key systems in the car, manufacturing of body joints and molds, and encapsulation of more solar cells.

The suspension for Renatus has been redesigned, due to critical issues with the old design. The previous version was run through a simulation to verify its failure before beginning the redesign. The new design is nearly complete and undergoing validation. Issues remaining with the new design are tire scrubbing and steering input when the suspension is activated, which are in the process of being resolved.

Along with the suspension, the electrical systems for Renatus were redesigned. To accommodate our three Raspberry Pi modules, we are designing and building new boards. The previously designed battery management system has been replaced with an Orion BMS, due to its reliability. We have designed and manufactured the main battery box, and are currently designing the power distribution system.

On the manufacturing side, we have made significant progress on various portions of the car. The wheel fairings for Renatus, meant to make the car more aerodynamic, are now complete. The upper and lower body joints, necessary to secure the two large pieces together, have been designed and manufactured. The joints are made from several layers of reinforced carbon fiber, which were then molded into the proper shape to fit snugly along the seam between the upper and lower body. The roll cage for Renatus was sent out to be welded together professionally. Once it was sent back, we drilled holes in the mounting points so that we can secure it properly to the chassis. The male windshield mold has been set and sanded down. We used it to create the female mold, which has been poured and cured. We are applying final patches to the female mold to seal any cracks. Once the female mold is finished, both will be sent to an outside group to be used in manufacturing the windshield.

Along with these major updates, smaller tasks, such as solar cell encapsulation and the creation of a mock chassis, have seen significant progress. 23 solar cell modules have been made so far, leaving 13 more to complete. The mock chassis is being constructed so that we can practice emergency exit procedures from the car. We are currently molding PVC to recreate our roll cage for the mock chassis, so we can more accurately represent the egress conditions.


Finally, I’d like to thank everyone who has devoted tremendous amounts of their time and effort to the club, new members and visiting alumni alike. You all have been incredibly helpful in the past year and a half and we look forward to your continued support of the club.

News up to the Unveiling

A lot has been accomplished since February. First off, the electrical team worked on the solar arrays and tabbed many two by 5 arrays together. Two panels were encapsulated in the easy bake oven. One of them melted the bag to the solar array and was ruined. The other one had wrinkled eva probably due to the high vacuum pressure that is encapsulated at. It will still work but it is not the intended product.

On the design side, the canopy bubble shield was sent to out to be manufactured in addition the remaining fairing molds, motor housing, and canopy. The suspension design was finished and sent that out as well to be machined.

The manufacturing team made the most progress in the past couple of months. We cut out the coring and foam for the lower body mold. After those layups were finished, we then put on the final layer of carbon fiber to the lower body mold. We used an envelope bag for this last layup and unfortunately it ruined the wheel wells of the lower body mold. We remade them and sent them to Bob Rohrman to be painted. We finished painting and sanding the fairing molds and put down 2 layers of carbon fiber for each mold. We also redid the leading edge layup in order to give us more material to work with. The fairings and canopy were all mated together using either kevlar or fiberglass. In addition to the work done on the fairings and lower body, the chassis was also worked on. The pieces for the chassis arrived just before spring break and most of the driver box was finished by the end of spring break. The chassis is now nearly complete and still needs some additional carbon fiber joints to be added for structural integrity. 

Before the unveling, we had a finished lower and upper body mold. We finished all of our fairing but did not have the method of attaching them finalized.  Our canopy does not yet have the bubble shield but that should be coming in within the next few weeks. 

As a final word, I wanted to thank everyone who has helped over the past few months. The amount of hours that were devoted to this car by this team's members is staggering and yet we still have more to do. Thank you for your continued commitments to the team and I can't wait to see you at the next meeting.

Weekly News - February 1st, 2016

We have completed chassis panel testing for all of the different joints we will have. The front and rear collision and roll cage tests are currently being performed. On the electrical side, solar arrays started to be tabbed but the solder wouldn't stick to the arrays as well as expected. We also experience some overheating of the solar arrays when attempting to solder. More tests on the soldering of the solar arrays need to be conducted. The lower body layup had more work done on it this week; the layup did not go so well as we would have like because we used frecoat instead of wax on the lower body. We also continued to sand down our fairings. This coming week, we will need to start cutting coring and send out the remaining fairing molds to be milled.

Weekly News - January 25th, 2016

Over the past two weeks, the team has continued work on the lower body mold. Dry runs on the lower body were conducted in order to find leaks in the mold which in turn were patched. The carbon fiber strips were cut for the entire lower body mold and the driver box fairing mold layups were started. The team also finished the construction of our second oven, allowing us to encapsulate twice as many solar cells. The next couple of weeks will entail finishing up the lower body mold, cutting the coring for the lower body, and starting solar array tabbing and encapsulation.

Weekly News - January 11th, 2016

Over break, we got back our fairing molds. The team built a paint booth, and worked on painting and sanding the molds. The suspension design was also finalized and we got our wheels back with the hubs milled out of them. We still have a lot to do this semester. The manufacturing team needs conduct the lower body mold layups, build the upper body structure, and mill the remaining molds. The electrical team needs to work on the solar array tabbing, solar array encapsulation, motor controller, battery box construction, and transitioning to Rasberry Pis.

Weekly News - November 28th, 2015

Over Thanksgiving, the team managed to perfect the encapsulation around the solar panels so as to both protect and allow the most light to reach the solar panels. The suspension design was also heavily edited and now only to have some finishing touches done upon the geometry and then have FEA conducted on it.

A huge thanks to everyone who spent their Thanksgiving vacation helping the team out.

Weekly News - November 14th, 2015

The team spent most of this week sanding the lower body mold. We figured out that wet sanding goes by much faster and so the mold is nearly finished and ready to conduct layups on. The design team also has continued to modify the suspension and conduct chassis panel testing. 

Thanks to everyone who made it out this weekend and sanded the lower body mold.

Weekly News - November 7th, 2015

This week, the manufacturing team conducted and finish the last upper body mold. The last mold was conducted by putting bagging material both underneath and on top of the carbon fiber mold in order to form a sandwich that would not leak through the cracks of the foam mold. The team also discovered that the connection between the foot and the vacuum pump was not air tight and fixed this to get over 20 psi of pressure on the mold. The chassis panel testing and suspension designs have also progressed and the Vechicle Design Report has also been started on. The electrical team has ordered parts for the second vacuum pump that will be used in the encapsulation oven as well as worked on the bypass diodes for the solar array. The team also was part of the Homecoming parade at Purdue and tested Pulsar's new batteries with great success.

Thanks to everyone who could make it out this weekend.

Weekly News - October 31st, 2015

The team continued work on the suspension design and started to conduct the chassis panel tests. More encapsulation testing has been done in order to make a better seal around the solar panels. The electrical team also finished up work on the motor controller board. On the manufacturing side, the upper body coring layup was completed this weekend and the last layer of carbon fiber for the upper mold has been pre-pregged.

Thanks to everyone who could make it out this weekend.

Weekly News - October 17th, 2015

We have continued to cut the foam for our leading edge, front fairing, and rear fairings this past weekend. We should be able to send out the rear fairings to APW and start cutting the front fairings at the AFL Lab. The electrical team  worked on debugging the LCU. We are have nearly finished up our second solar array encapsulation oven. We created some small touchup pieces of carbon fiber for the trailing edges as well as cut the coring for the upper body mold. Methods to improve the seal on the upper body mold are still being tested. The team also sent out the Preliminary Vehicle Design Report and have received feedback from our mechanical adviser for what to improve upon for the Vehicle Design Report due December 15th.

Weekly News - October 3rd, 2015

This past week, we continued work on the steering, suspension, and roll cage designs. We finished trimming the door mold and made the the first upper body mold layup. We did not get as strong of a seal as we would have liked; the result of this was that our mold buckled and bubbled. However, we have realized that by taking the peel ply off, adjusting the carbon fiber to lay flat, and then reapplying the peel ply will help with this issue. Work on the preliminary vehicle design report has continued and will need to finish by October 15th. In electrical news, the test encapsulation of a solar panel has been completed and the LCU board has been finished. 

Thanks to everyone who could make it this weekend.

Weekly News - September 26th, 2015

On the design side,  the team has completed the design of the steering mechanism as well as updated the roll cage and suspension design from feedback on the preliminary vehicle design report. We have also ordered our chassis panels and those should come in within the next week. At our weekend meetings, the door layup was completed with great success and the carbon fiber for the upper body molds was prepped. A second solar cell encapsulation oven was also started upon and should be finished next week in order to start the encapsulation process. In other electrical news, the batteries for the car also came in this weekend. Thanks to everyone who could make it this weekend.

Weekly News - September 19th, 2015

This past week, we sent in our preliminary design report and finished the sanding of the top mold. Initial layups for the door were attempted on Wednesday with little success. The team went down to Indianapolis to pick up carbon fiber sheets, honeycomb coring, and epoxy to redo the door layup. The templates for the door mold were made and the carbon fiber and coring was cut to size and are now ready once again for layups next week.

Weekly News - September 5th, 2015

On Monday, we sent our body molds to Mike Raisor to have them painted. Our preliminary design report was also split up and started upon. Most of Saturday was spent sanding the painted molds to make them as smooth as possible. After nearly 7 hours of sanding mostly by hand, there is still more to be sanded. Thanks to everyone who came out and sanded this weekend as well as Mike Raisor for painting our molds.

Purdue Solar Racing, 465 Northwestern Ave. West Lafayette, IN 47907