STEERING SYSTEM for MINI BAJA CAR Benjamin Genre Advisor: Dr. Ho-Hoon Lee   Dr. Cris Koutsougeras ET 493 Senior Design Project II Fall 2017

Goals of Project Construct a steering system for a mini baja car whose design lowers steering error. Acquire and assemble parts in the most cost effective way. Test and record results.

Importance of Steering Design Proper steering design aids in comfort of the driver. It helps to reduce skidding and wear on the tires Normally follow the Ackerman Steering Principle

Ackerman Steering Principle States that the axial lines of all the wheels should meet at the same point.

Steering Error When the projections of the two front wheels do not meet at the same point on the rear axle’s axis. Steering error will occur with the use of commercial parts. Ackermann Steering Error

By changing the distance from the front axle to the rack, the steering error also changes. The distance from the front axle to the placement of the rack-and-pinion is the main design point. Rack and Pinion System

Background Last semester a c-program capable of calculating steering error was created. There were two frame design teams, so the program helped by allowing quick and flexible calculations.

Flow Chart Program made with Microsoft Visual Studio. At the start of the program, the user is asked to input the constants of the design. These include: Length from front axle to rear axle. Width of car. Length of the rack and pinion. Length of steering arm. Angle between steering arm and wheel. Maximum displacement of rack. Initial value of S (the distance between the front axle and rack.) Maximum value of S.

Flow Chart Everything is calculated as a function of S. Prints values of S, lt, θl, θr, and es. S is increased and then compared to Smax. If S < Smax, the calculations start over with new value for S If S > Smax, then the program ends.

Steering Error Output for Frame 1 Table Frame 1 Steering Error Output for Frame 1 s (in) lt (in) Ol (rad) Or (rad) es (in) 2.500000 12.435833 -2.698303 1.561025 32.791946 2.600000 12.425493 -2.681408 1.542593 27.116013 2.700000 12.415951 -2.664580 1.523945 21.834167 2.800000 12.407207 -2.647819 1.505060 16.904785 2.900000 12.399262 -2.631127 1.485913 12.291878 3.000000 12.392121 -2.614508 1.466477 7.964203 3.099999 12.385782 -2.597961 1.446716 3.894279 3.199999 12.380248 -2.581490 1.426593 0.058311 3.299999 12.375521 -2.565096 1.406059 3.564545 3.399999 12.371598 -2.548780 1.385054 -6.993240 3.499999 12.368484 -2.532545 1.363509 -10.244102 3.599999 12.366177 -2.516391 1.341329 -13.331718 3.699999 12.364678 -2.500320 1.318400 -16.269325

Cost Analysis *Maximum cost if available part are unusable ac425020-12 QTY Cost Each Cost 11-inch Rack and Pinion 425145 1 $ 110.91 Double U-Joint 425271-1 $ 72.25 Tie rods 425120 2 $ 25.92 $ 51.84 Steering Shaft Coupler 425251 $ 15.84 $ 31.68 Tie Rod Clevis 425120CV $ 5.83 $ 11.66 Splined Shaft  ac425020-12 3 $ 12.25 $ 36.75 Steering Wheel GSW187 $ 59.00 Steering Knucle Set MA_319997 $ 323.99 *Maximum cost if available part are unusable

Parts 11” Rack-and-Pinion Double U-Joint Tie Rods Steering Shaft Coupler Splined Shaft

Deliverables Confirm dimensions of steering design. Evaluate available resources. Create a cost analysis of steering parts needed. Acquire all parts for steering system. Assemble parts together. Test assembled parts with original design values.

Timeline Timeline Deliverables Early Sept. –Mid Sept. -Confirm dimensions of design. -Evaluate avalible resources. Mid Sept.- Early Oct. -Create cost analysis for steering parts. -Gather steering parts. Early Oct.- Mid Oct. -Begin assembling. Mid Oct.- Early Nov. -Continue assembling parts -Test and compare assembled parts with orginal design. Early Nov.- Early Dec. -Record data. -Perform final test of steering and fine tune.