Abstract:
Traditional heavy vehicle legislation prescriptively regulates weights, dimensions, etc.,
whereas the PBS (Performance Based Standards) approach regulates vehicle safety
performance. The Smart Truck Pilot Project in South Africa is tasked with evaluating the
potential benefits of PBS regulation on the increase in transport efficiency, improvement in
vehicle safety, reduction in the environmental impact and reduction in infrastructure
damage. The flexibility in PBS allows for a design to optimally meet operator needs. The
Smart Truck programme has shown that these benefits can be realised by adopting the
PBS approach, however the development of a PBS heavy vehicle is associated with
additional heavy vehicle dynamics analysis and design costs which can deter small
operators. The University of Pretoria VDG (Vehicle Dynamics Group) has developed a
reconfigurable multi-axle, multi-articulation heavy vehicle linear state space model that
operators and designers can use in the early stages of development. This model can be
used to conduct a feasibility study to determine if a PBS vehicle will have a positive ROI
(Return on Investment) for the operator. Also, this model can be used in concept design to
identify the necessary hardware (tyres, suspension, etc.) and evaluate the proposed
vehicle’s performance. The model does not require a vehicle dynamics specialist and can
be used by the designers themselves. Further, the model can be operated in common
coding languages (e.g. MATLAB, python), thus reducing the cost of PBS development.
PBS vehicle development cost can be reduced by conducting the majority of the vehicle
development (feasibility study and conceptual design) with this linear state space vehicle
model, which is reasonably accurate to specify the vehicle hardware and parameters to
meet the operator needs in the concept stage. The linear state space vehicle model can
then be used to generate a non-linear multi-body model in Adams or TruckSim for the
detailed design stage and the final PBS evaluation.
