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

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

Introduction Performance-based standards Low-speed manoeuvrability assessment Motivation

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

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

Low-speed manoeuvrability measures

Low-speed manoeuvrability measures

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

GeoTrack overview

Overview Add input parameters needed

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

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

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

Field testing validation

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

Field test overview 90 deg 12.5 m radius Trajectory markings

Test site imaging and image warping y y x Original ground-view photo x Rectified birds-eye view

Image stitching and processing

Field test results Update new plot GeoTrack Vehicle test

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)

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

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

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.

Thank you. Contact: cdsaxe@csir.co.za

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