Accurate swept paths for complex OSOW vehicles

swept-pth-acurat-pth-01.mp4 11:48

Most vehicles are simplistic, consisting of a simple tractor/trailer configuration with steering at the front axle only. With sound judgment and guidance from the FDM, these swept paths can be created with relative ease.

More complicated vehicles are appearing statewide. These vehicles include a combination of features or restrictions that can be difficult to model.

• greater than 2 parts (not difficult by itself)
• steerable rear axles (either linked or independent)
  • Independent steerable rear axles are the most difficult because it requires the User, not the software, to make decisions/judgments about the capability of the vehicle and what is realistic.
• ground clearance restrictions (3D modeling is required)
• yaw restrictions, also known as articulation angle (not difficult by itself)
• pitch and roll restrictions (3D modeling required)

Overview

Step 1: Identify the project characteristics – What is the design vehicle or vehicles?

Step 2: Gather physical vehicle data – dimensions, angle, etc.

Step 3: Document real-world swept paths – Survey vehicle maneuvers (Vehicles with more than 1 steering axle) Step 4: Build the vehicle model – Swept path software

Step 5: Trace the real-world swept paths – Calibrate your model (Vehicles with more than 1 steering axle) Step 6: Coordinate with the trucking company – Get feedback from the experts

Step 7: Make refinements – Adjust based on comments

 

Step 1: Identify the project characteristics

• Is it on the OSOW freight network?
• The OSOW vehicles listed in the FDM may not be all inclusive. Include freight as a topic for your business outreach
• The project may be "the last mile"
• Is your project en route to a large bridge?

Step 2: Gather physical vehicle data

• Body dimensions
• Load dimensions/position
• Axle spacing
• King pin locations
• Steering angle(s)
• Articulation angle(s)
• Ground clearance
• Lock to Lock Time

Step 3: Document real-world swept paths (Vehicles with rear steering)

• Coordinate with trucking company
• Trace the swept path (front and rear tires) through a 90 degree turn
• The more of these you do, the more refined the model will be
• Survey the painted swept path at the intersection
• Observe and document details like rear axle rate of articulation (∆ steering angle/distanced traveled)

Step 4: Build the vehicle model

• Input the vehicle data into the swept path software
• Use Methods Development as a resource
• Double check your inputs and confirm with trucking company

Step 5: Trace the real-world swept paths (Vehicles with more than 1 steering axle)

• Use the survey data as a guide to drive the vehicle through the intersection
• This will act as an aid for how to drive other intersections. (Calibration)
• Pay close attention to the rate of articulation at the rear.

Step 6: Coordinate with the trucking company

• Share your result with the trucking company. Animate the swept path. Ask them questions like:
• Does this look like a realistic way to maneuver this intersection?
• Are there any features that would make this intersection easier to drive?

Step 7: Make refinements

• Use the feedback from the trucking company to refine the swept path
• Make adjustments to the intersection geometry Send an updated animation to the trucking company.