|Project Summary||Project Information|
One major cause of bicycling accidents is a vehicle overtaking the cyclist from the rear. Currently, riders have the option to use a side mounted mirror system to aid in their vision to the rear. However, this mirror arrangement has several drawbacks: distorted vision, difficult adjustment, and view obstruction. A multiple mirror system has been proposed by industrial design student Rob Fish, as seen in the following presentation. This system is mounted over the top of the helmet to provide a wide angle field of view behind the rider while being above the forward line of sight.
There were multiple issues with the prototype developed by Rob Fish. This senior design project will develop a helmet mounted mirror system that corrects for the issues seen in the prototype. Safety will be the biggest concern in designing and developing this system. Other considerations to be accounted for are minimizing the forward vision obstruction, maximizing the rear vision angle and image quality, and maintaining the proper image orientation. The ultimate goal will be a final product that is marketable in the cycling community that can be adaptable to multiple helmet styles currently on the market. However, the success of this senior design project will not be contingent on this ultimate goal being reached. This project will be deemed successful if it shows an improvement over the prototype in the areas detailed above. This project has the potential to be continued on in future MSD projects to perfect the design. The Project Readiness Package gives additional details about the senior design project overview.
This project is a student initiated project and was developed by Stephen Wess through the Design Project Management course. Due to this, there is no direct customer for the project. The acting customer for this project is Dr. Bernard Brooks, a professor in the School of Mathematical Sciences at RIT. Dr. Brooks is an avid cyclist and is familiar with the needs of the cycling community in developing an improved rear vision system.
Detailed Design & Preliminary Testing
Mirror Surface: Options for mirror surface were reflective Mylar, chrome window tint, spray on mirror, and acrylic. Each material was obtained and tested by the team for reflective image quality. Acrylic was determined to be optimal solution
Geometric Optics Analysis: Two and three mirror systems were analyzed for this design. A 50th percentile male head was used to determine the positions, curvature, and dimensions of the mirrors. Sensitivity analysis showed that the dual mirror system performed better.
Drop Test Analysis: To simulate the impact stress of dropping the designed system, a drop test analysis was performed using SolidWorks Simulation package. From this, adjustments were made to the design to strengthen and optimize the system
Finalized Concept & Rapid Prototyping
Dual Mirror System: Front mirror is in the user’s peripherals while the top concave mirror reflects the image behind the cyclist in the proper orientation.
Gooseneck: Gooseneck tubing is flexible enough to allow the system to attach to multiple helmet styles yet rigid enough to support the top mirror. Snap-fit Attachment: Snap-fits were utilized to increase the ease of assembling the system.
Dual-lock: Dual Lock allows users to easily attach and detach the bike helmet mirror system to helmets. ABS: ABS plastic was chosen for material properties including resistance to water, heat, and UV, and for its ability to be both 3D printed and injection molded.
Rapid Prototyped: The finalized concept was prototyped on the Fused Deposition Modeling (FDM) machine in RIT’s Brinkman lab. Acrylic: Heat was applied to the acrylic until it was pliable. Mirror was then molded to the proper curvature and attached using an adhesive.
Testing & Results
Rear Viewing Angle: The rear viewing angle specification calls for a minimum angle of 10 degrees (marginal) and 25 degrees (ideal). The system displayed a viewing angle of 40 degrees.
Rear Viewing Distance: The specifications require a distance of 130 feet (marginal) and 200 feet (ideal). The system was able to identify a vehicle at over 270 ft.
Wind Speed Resistance: The wind speed requirement was 45 mph (marginal) and 65 mph (ideal). RIT’s wind tunnel was utilized for testing. The system stayed attached to the helmet at the wind tunnel’s maximum speed of 130 mph. System Weight: The marginal value of the weight specification was 0.775 lbs., the total component weight was measured to be 0.403 lbs
The team successfully carried a concept proposed by an industrial design student into a working prototype that performs well with respect to the predefined engineering specifications.
Documentation Throughout Design Process: It is important to document the decision making progress through the design phase so people outside the group can follow the design’s progression.
Communication: Staying on the same page was key for the group in order to move forward with the project as one.
Back-up Plans: Keeping an updated Risk Assessment log was critical to project success. When we ran into issues regarding the reflective surface, we knew which materials to test next.
Complete Testing: Finish testing specifications for (1) System Break Away Force and (2) Drop from Height.
Improved Stability: Design additional support for the front mirror in order to reduce vibrations.
Weight Reduction: Asses which components of the assembly weigh the most and redesign for lighter weight.
|Zachary Kirsch||Mechanical Engineer, PMfirstname.lastname@example.org|
|Martin Savage||Mechanical Engineeremail@example.com|
|Olivia Scheibel||Mechanical Engineerfirstname.lastname@example.org|
|Henry Woltag||Industrial and Systems Engineeremail@example.com|
Table of Contents - MSD I
|Planning & Execution||Systems Design||Detailed Design||Project Review|
Table of Contents - MSD II
|Planning & Execution||Build, Test, Document||Final Project|