Week 5

As we head into Week 5, our basic planning will be implemented into practical construction of at least a prototype of the actual vehicle.  Naturally, it is highly unlikely that our initial design will be our final, but we must have something tangible to test out first.  Besides the physical side, basic modeling of our own solar panel, motor, and chassis will be done soon as well.  Once these models are complete, we can utilize them and the equations given to us by Dr. Scoles to maximize our vehicle's performance.  Below are two views of a very basic chassis design created with Pro/ENGINEER.

Figure 1: The front and right side view of an initial design of the basic chassis.  [1]

Figure 2: The back and left side view of an initial design of the basic chassis.  [2]

R&D

We've already done some basic preparations for actually constructing the model car.  Orthographic drawings of an initial design have been done and will be posted eventually.  A ProENGINEER CAD drawing of a basic chassis has also been completed.  The motor itself has been tested in conjunction with the solar panel and is fully functional.

As for quantitative research, two general system model equations have been given to us; one for the solar panel and one for the DC motor.



Figure 1: The electrical system relating the current of the solar panel to the current of the DC motor.  [1]

 Our specific model of motor, however, came with its own data sheet detailing information such as the general speed it can provide, the power it can generate, and the amount of current it can draw.



Figure 2: The data table and graph from the data sheet of the model of motor we are using, RE-260RA-18130.  [2]

References:
[1] Scoles,Kevin (2012) System Models [Online] Available FTP: https://learning.dcollege.net/webct/urw/tp2604862946111.lc2491898185011//RelativeResourceManager?contentID=2625276825091
[2] Mabuchi Motor (2012) RE-260RA [Online] Available FTP: http://www.pololu.com/file/download/re_260ra.pdf?file_id=0J17

Design Ideas/Equations to Take into Account



Equation 1: Power needed to move a vehicle at speed v when acted on by various forces (rolling resistance, headwind, etc.)  [1]

 Using this equation given to us by Dr. Scoles, we will attempt to maximize our vehicle's performance by first taking into account which variables can be manipulated, and then determining how much effect we can have on each variable in either maximizing or minimizing it.  For example, g, the acceleration of gravity obviously cannot be changed; however, m(car), the mass of the car will be reduced as much as possible while eta(mech), mechanical efficiency will be maximized.

References:
[1] Scoles,Kevin. (2012) Power Needed [Online] Available FTP:https://learning.dcollege.net/webct/urw/tp2604862946111.lc2491898185011//RelativeResourceManager?contentID=2608823090111

Kit Ordered

We ordered our solar panel kit over the weekend, and it should arrive by the end of the week.  It cost about $40.00 ncluding shipping.  The kit basically included the solar panel, the motor, and the wheels.  An extra accessories kit was purchased for about $4.00, and it included some axles and other potentially necessary tools.

Initial Design Brainstorming

Overall objectives are to minimize drag, rolling resistance, and mass (of car and wheels).  Must be able to integrate the addition of the solar panel and the payload without reducing the aerodynamic design of the car.  Basic ideas are to use lightweight materials, keep design simple yet efficient, and maintain stability of the chassis.
We talked about small aspects such as the angle of the solar panel which cannot be modified in any other way, the material/mass of the wheels to reduce moment of inertia, and the overall integration of the panel with the motor.
We also began looking at other solar sprint car designs such as the one shown below.

http://teachers.egfi-k12.org/wp-content/uploads/2010/01/solarcar.jpg