DC Ergonomic Analysis

What is Ergonomics

Intro to Ergonomics PPT Presentation

In the world of ergonomics, drivers are defined by their height percentile. For example, the 5th percentile woman is 4' 11", meaning that 95% of women are taller than this. Anthropometric data defines the length of every part of the human body relative to the height percentile, so that our team may simulate the entire driver from just knowing their height. FSAE requires the vehicle to be drivable for 5th percentile woman to 95th percentile man. Drivable encompasses 3 things - driver's available force, fatigue, and visibility.

Available Force

RAMSIS Force Display

Every component that the subsystem designs has to be able to be operated by any driver. Some components, like the brakes, have to be operated for up to 15 minutes at a time for the endurance race. These are designed to use 60% of the driver's maximum effort, or 'tolerable effort'. Other components, like the clutch handle, only have to be operated at the beginning of the race to get the car rolling in 1st gear. For these, the driver's maximum effort is usable (but we try to remain well below). On the flip side, there are downsides to a car that is too easy to operate. A driver who doesn't feel adequate force feedback can easily oversteer or lock up the brakes and spin out We design all of our custom mechanical components, choose COTS options, and run simulations and tests to ensure that we build a racecar that takes just the right amount of effort to drive. Force data is found through the manikin software RAMSIS, driver tests, and vehicle load cells/ strain gauges. Available force is the amount of force that a driver has. Required force is how much it takes to drive. Available must be greater than the required force.

MATLAB Fatigue Manikin

Fatigue

Along with force, the positioning of the components significantly impacts how fatigued a driver will become. This fatigue is different that material fatigue. Just like some car components will fail after a certain number of cycles, so too will our driver's ability to drive taper off. A steering wheel that is mounted too far from the driver, or a clutch handle that forces the arm to scrunch up raise the fatigue rating for those components. For some parts, the fatigue rating weighs more heavily, especially those used in out autocross and endurance races. The position of where everything sits in the car determines how a driver will maintain their effort and agility, especially the design of the vehicle's seat. We can use our GTMS-made MATLAB resources to simulate fatigue for a range of drivers. It uses data from RAMSIS that correlated joint angles to fatigue through a penalty function. An image of the simulated driver is shown right, and resources can be found below

RAMSIS Direct Vision Display

Visibility

Visibility ensures that everything is in the right sphere of vision for the driver. The dashboard should be in their periphery vision, but not the direct vision (as to mot interfere with the road). The drive should be able to see the cones on the track during the tightest corner (taken from an endurance or autocross lap) with enough time to react. While a lower driver is desirable for center of gravity, a higher driver is desirable for visibility. Visibility must not be compromised for all drivers.

Ergo Jigs and Sims

2023 Ergonomic Jig

• Purpose
• Materials
• Capabilities
• Current Status

2025 Ergonomic Jig/ Sim

• Purpose
• Materials
• Capabilities
• Current Status

DC 2025 Ergonomic Jig & Simulator

Ergonomic Resources

• F24 Ergonomics Design Binder - discusses applications of RAMSIS, ergo jigs, and MATLAB on the 2024 GTMS Racecar
• MATLAB Simulations SharePoint folder
• Research Paper 1 - Accompanies MATLAB Fatigue and Pain Calc Script
• Research Paper 2 - Accompanies MATLAB [PSO] Scripts
• What is PSO PPT - Particle Swarm Optimization, Accompanies MATLAB [PSO] Scripts
• 1988 ANTHROPOMETRIC SURVEY OF U.S. ARMY PERSONNEL
• Anthropometric Data Spreadsheets *use Ctrl + F using the survey above to lookup unfamiliar terms*
• RAMSIS Data Spreadsheets