Ergonomic Path Planning for Autonomous Vehicles - An investigation on the effect of transition curves on Handling Behaviour

As vehicles transcend into higher levels of automation, a key factor that will determine a comfortable driving experience for the passengers will be the handling behaviour of the autonomous vehicles. Path planning will serve an important role in ensuring smooth and comfortable handling. The present study develops a well defined universal scale to define the handling behaviour of autonomous vehicles using different ergonomic path planning tools. Firstly, a reference track is designed to incorporate the worst handling. Followed by designing ergonomic roads using transition curves such as B-spline, Bezier and Hermite curves to investigate the impact of these curves on handling behaviour. Trajectory tracking of an 8 degree of freedom vehicle model is then studied using curvature dependent and curvature independent controllers to draw a comparison. Results are then compared and evaluated using a universal cost function to determine the optimal transition curve for handling. Results indicate that 3-point defined curves in general perform better handling with B-spline evaluated as the best handling transition curve for 4-point defined curves. Further research is recommended by utilising key characteristics of the transition curves like local control and non-uniformity.