RW-2

Technical Update

    Welcome back Buckeye Current and friends!  The semester has gotten off to a great start and the team is continuing to grow in support and collective enthusiasm.  There are many projects underway, and the design of the complete RW-2x is nearing finalization.  Here is an overview of the technical work being done and projects that we will be starting soon.

 

The bike is in pieces…  Actually the frame has been completely disassembled and Polina and Brody are going to be sandblasting it today to remove the powder coat.  The frame welds will then be inspected to make sure that no structural integrity has been compromised from last year’s race season.

 

The batteries are being discharged with the AV-900 in 15-20 modules groups in order to characterize the actual power density and capacity of every cell.  We are then immediately charging the batteries after discharge, as this is necessary to safely store them.  This process is about a third of the way complete and will continue next Sunday.  When complete we will select our pack by choosing the best cells in our stock.  We are still using the AEE batteries that were used last year, and although they are not the most energy dense cells on the market, we have a great deal of experience with them and have many improvements in store from last year’s pack design.  Nick has put together a new pack configuration that should increase our total capacity from last year.  Polina is working diligently to convert our recent frame scan into a usable CAD format, with which we will verify that the new pack design will actually fit in the bike.

 

On the electrical side, our data acquisition system has been completely redesigned in order to prevent communication dropout between the drive control and motor controller.  Jenn has created a CAN mirror circuit that will allow the drive control and motor controller to communicate on a CAN bus isolated from the data acquisition CAN bus.  Motor controller data can be read from this CAN mirror but if any communication issues occur on the DAQ side, this will not affect motor controller function.  This board has been received and populated, and testing is currently underway.  Jenn has also created a rider display utilizing an LCD that is connected to the CAN bus, so any CAN signals can be displayed with the push of a button such as motor current, remaining amp hours, battery voltage, etc.  Anil has developed a 12V battery monitoring circuit that will protect our 12V battery from being destroyed as it almost was several times last year.  This board is also in the testing phase.  Aaron’s Magic CAN Node Capstone project is undergoing testing.  This Magic CAN node is a very convenient device that allows virtually any sensor to be quickly integrated and the node will convert and spit the sensor’s data onto the CAN bus for data logging.  Aaron has also developed a new battery management board that he calls the Battery Interface Module (BIM).  This BIM incorporates six bq ICs with an onboard CAN interface.  This will allow each BIM to monitor voltages for up to 36 cells, a great improvement from last year’s BMMs which could only monitor 12 cells.  The onboard CAN interface will also help eliminate EM interference on the communication lines that caused complete BMS comm failure last year whenever the motor began spinning.  These boards are going to be very costly to produce so we are still looking into suppliers and possible sponsorships.

 

On the software side we are optimizing our CANcorder (CAN datalogger) code to be be faster. We have created a complete template for all the "Magic CAN Nodes" that will serve as a basis for all the nodes on the bike. Both the BIM and CAN mirror codes have been written and partially tested. We are in the progress of writing code for the rider display and drive controls.

 

A lot of progress has been made toward completing the design of the RW-2x, but several large projects remain.  Most importantly we need to design and produce fairings for the bike.  This is not necessarily behind schedule as the frame design needs to be finalized before we can begin planning the bodywork, but this is a very timely process that needs a jump start at this point.  A coolant system design has been developed but plumbing and testing are critical steps that will begin soon.  We have several different electronic enclosures throughout the bike (contactor box, rider display, CAN node and BIM housing) that have been designed, but we now need to get them 3D printed.  This covers the majority of the technical elements of the bike aside from suspension, gearing, and tire selection, which are not priorities at this point in time.

 

Last year we had a total of two track days in the US before we had to ship the RW-2 off to the Isle of Man.  This year we need to allow for much more testing, and we hope to begin by no later than spring break.  The goal at this point is to take the completed bike to the Road Atlanta track two months from now.  We have a lot of work ahead of us but it is apparent to anybody who has visited the paddock recently that the talent and motivation to achieve our goals have never been more alive.  Keep an eye out for more team updates, things are moving fast!

 

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