1. Christopher de Saxe, Robert Berman CSIR Built Environment
Contents
GeoTrack An efficient simulation tool for the analysis of heavy vehicle manoeuvrability
Christopher de Saxe, Robert Berman
CSIR Built Environment
9 July 2018
37th Southern African Transport Conference

2. Outline Introduction GeoTrack overview Field testing validation
Performance-Based Standards (PBS)
Low speed manoeuvrability: metrics & assessment
Motivation for GeoTrack
GeoTrack overview
Field testing validation
Closing remarks
Applications of GeoTrack in industry and research
Conclusions and future development

3. Introduction Performance-based standards
Low-speed manoeuvrability assessment
Motivation

4. Performance-Based Standards
Prescriptive Standards
Performance-Based Standards
Prescriptive Standards
Performance-Based Standards
What the vehicle looks like
What the vehicle can do
Governs mass and dimensions
Governs actual on-road performance
Constrains productivity
Allows heavier and/or larger vehicles
Constrains innovation
Promotes innovation
Images courtesy of the Australian National Transport Commission

5. Performance-Based Standards
Manoeuvre/Test
Performance Standard
Low-speed 90° turn (5 km/h)
Low-speed swept path
Tail swing
Frontal swing
DoM & MoD
Steer-tyre friction demand
High-speed lane-change (80 km/h)
Rearward amplification
High-speed transient offtracking
Rollover
Static rollover threshold
High-speed pulse steer (80 km/h)
Yaw damping coefficient
High-speed on uneven road (90 km/h)
Tracking ability on a straight path
Various (driveability standards)
Startability
Gradeability A
Gradeability B
Acceleration Capability

6. Low-speed manoeuvrability measures

7. Low-speed manoeuvrability measures

8. Motivation for GeoTrack
Existing tools and methods
Multibody dynamics software (TruckSIM, Adams)
Analytical models (differential solvers)
Physical testing
Limitations
Model setup and solver time
Detailed vehicle parameters needed
Analytically defined paths
Restricted vehicle models (subject to additional licences)
High costs
Need
Unlimited vehicle combinations
Minimal vehicle parameters (preliminary design drawings)
Computationally efficient (design optimisation)
PBS analysis + route assessment functionality

9. GeoTrack overview

10. Overview
Add input parameters needed

11. PBS assessment results
Swept path
Tail swing
Frontal swing, DoM, MoD

12. Generalised assessment results
Road extremities
Vehicle paths
Google maps image
Scale factor

13. Highlights Only basic vehicle dimensions needed
Unlimited vehicle combinations and lengths
Solves in a few seconds (optimisation friendly)
Compatible with any path type
Multiple path-following models
Pre-defined PBS manoeuvres and metrics
Standalone lightweight solver, independent of more complex expensive software

14. Field testing validation

15. Buhle Betfu A-double (MAN + Afrit)
Field test overview
Buhle Betfu A-double (MAN + Afrit)
Trajectory marking

16. Field test overview
90 deg 12.5 m radius
Trajectory markings

17. Test site imaging and image warpingy y x
Original ground-view photo x
Rectified birds-eye view

18. Image stitching and processing

19. Field test results
Update new plot
GeoTrack
Vehicle test

20. Also, average 2% error in validations against TruckSIM
Field test results
Field test
GeoTrack
Difference
Swept Path
6.58 m
6.82 m
−3.4%
Tail Swing
0.32 m
0.0%
Frontal Swing
0.56 m
0.59 m
−5.1%
Difference of Maxima
−0.31 m
−0.34 m
−8.8%
Maximum of Difference
0.34 m
Also, average 2% error in validations against TruckSIM
(C de Saxe, MSc dissertation, 2012)

21. Closing remarks Applications of GeoTrack in industry/research
Conclusions and future work

22. Applications of GeoTrack
Research applications:
Benade et al, “A pro-forma design for car-carriers: low-speed performance-based standards,” SATC, 2015
Berman et al, “Hyperformance: Predicting high-speed performance of a B-double,” HVTT14, 2016
De Saxe et al, “Tail swing performance of the South African car-carrier fleet,” HVTT12, 2012
Industry applications:
PBS route clearance for provinces
PBS vehicle optimisation (operators and trailer OEMs)
Car-carrier loading restrictions

23. Conclusions & future development
GeoTrack is a lightweight and versatile vehicle manoeuvreability simulation tool, validated through simulation and field testing.
It has been tailored for both PBS and generic applications.
It is currently available for research and commercial use on a consulting basis
We are aiming to package it as a standalone product or online tool in future, if the need exists.

24. Thank you.
Contact:

25. Image distortion correction
Calibration images
Distorted
Undistorted