International Journal of Vehicle Design (4 papers in press)

Regular Issues

• Novel design concept for an automotive proving ground supporting multilevel CAV development  
  by Adam Nyerges, Zsolt Szalay, Zoltan Hamar 
  Abstract: Technological changes usually bring new possibilities in everyday life. Thanks to the recent evolution in science and technology, road transport is going to change radically. Today's complex assistant systems help the human driver to manoeuvre the vehicle safely. In the near future, connected and highly automated vehicles will also appear on the road, in multiple transport modes. Higher vehicle automation levels rely on disruptive technologies that simply cannot be tested and approved in the currently used sustaining technologies format. As validation processes become more complicated they require a more specific and ever-changing test environment. Current autonomous vehicle test environments are developed around activities that mostly concentrate on an urban test area, while every single element of the new Hungarian automotive proving ground is dedicated to the testing and validation of connected and automated vehicles. This paper will discuss this complex and integrated design concept, illustrating the unique points that differentiate the new Hungarian test facility from that of a conventional vehicle test track as well as from other current autonomous vehicle testing areas.
  Keywords: connected and automated vehicles; autonomous driving; self-driving vehicles; testing and validation; test track; proving ground; smart city; intelligent transport.
  
  
• Mine car suspension parameter optimisation based on improved particle swarm optimisation and approximation model  
  by Jun Zhang, Xin Li, Duyou Liu 
  Abstract: A suspension parameter optimization method is proposed in this paper to improve mine car ride comfort. The most influential parameters on vehicle ride comfort are chosen as optimisation variables by analysing parameter sensitivity using a 7-degrees-of-freedom vehicle model. A simplified regression model based on the response surface method accelerates the optimisation process. An improved chaos particle swarm optimisation (ICPSO) approach is proposed based on standard particle swarm optimisation to optimise suspension parameters in the regression model. The ideal match of suspension parameters is obtained. Simulation results show that improved suspension parameters can greatly ensure the weighted root mean square acceleration and tyre dynamic loads; additionally, suspension dynamic deflections are limited within an allowable range. Test results reveal that the suspension multi-parameter optimisation method based on ICPSO can improve vehicle ride comfort. Therefore, this method can be used to guide future research and development of suspension systems.
  Keywords: mine car ride comfort; suspension parameter optimisation; Particle swarm optimisation; approximation model.
  
  
• Design and evaluation a passive inertial mass device for car suspension system  
  by Shuai Yang, Chuan Li 
  Abstract: A new adaptive nylon flywheel is proposed, which can achieve passive vibration control by generating variable equivalent mass. With changing rotational speed, the location of sliders in the slots changes, which leads to the creation of variable equivalent mass. Owing to the light weight and high strength of the nylon material, a higher changing ratio of equivalent mass can be achieved. To verify the performance of the adaptive nylon flywheel, the inverse screw system was applied. By using zero, impulse and sinusoidal input as road excitation, the proposed car suspension system is evaluated from riding comfort and tyre grip. Simulation results show the proposed suspension system provides better performance than traditional suspension system under most circumstances.
  Keywords: inertial mass; passive; car suspension; adaptive flywheel.
  
  

Special Issue on: Multi-Objective Design and Structural Optimisation of Vehicle Components with Nature-Inspired Optimisation Algorithms

• Determination of dynamic axle load using suspension deflection method for the load distribution optimisation of multi-axle vehicles  
  by Mustafa Umut Karaoğlan, Nusret Sefa Kuralay 
  Abstract: Identification of dynamic axle loads in multi-axle vehicles requires complex calculation methods because of the hyperstatic solving necessity. Existing methods for identification of axle loads are mostly based on response simulation by using a beam element to overcome the hyperstatic problem using numerical solutions. In this study, a suspension deflection method is proposed to determine the dynamic axle loads to optimisation of load distribution of a multi-axle vehicle having more than two axles. Load distribution optimisation for each axle is required for the definitions of maximum and minimum weights of the vehicle dynamically to provide better vehicle handling dynamics and axle strength. The determination of the dynamic axle loads is performed for a driving conditions with a climbing angle and a longitudinal acceleration to optimise the loads at the axles of the vehicle using a suspension deflection method. General equations and calculation methodology are presented for a multi-axle vehicle. Then, a numerical example is implemented using the suspension deflection method for a four-axle vehicle as a case study. The effect of the wheelbase, acceleration, climbing and characteristics of the suspension spring on load distribution are investigated for the optimisation of the loads on each axle of the vehicle. Finally, it is shown that the suspension deflection method is more simple and useful than other approaches to define the dynamic axle loads for an optimisation study of vehicles with multiple axles.
  Keywords: axle load optimisation; suspension deflection method; multi-axle vehicles; load distribution.