Proposal for a transition curve with smoothly changing curvature using multiple clothoid curve

Abstract

This paper presents theoretical research on an optimum transition curve with smoothly changing curvature using a multiple clothoid curve for improving the occupant ride comfort of automobiles. At the connecting points between an inlet straight line and a circular arc, or between a circular arc and an outlet straight line, vehicles cannot run smoothly owing to the discontinuity of curvature. Especially, the vehicles equipped with a driving support device which assists driver's steering operation or performs steering operation instead of a driver will increase both unstable movement of vehicle and discomforts of occupant.Moreover, the discontinuity of curvature in the connecting points makes the control of advanced accuracy of apparatus difficult.In order to solve such problems, three dimensional vehicle occupant model which is 21 degrees of freedom is assembled, and the multiple clothoid curve is proposed as a new transition curve. The validity of the multiple clothoid curve is shown as compared with the case where it is interpolated by a single clothoid curve or by a non-interpolation. It was found that the influence of the multiple clothoid curve on vehicle movement and ride comfort is superior to those of the single clothoid curve or the non-interpolation. Some results are presented in the form of parametric plots.

Investigation of trajectory planning of a travel route while turning at an intersection

“…However, the theory shown in this study can be applied in different central angles of circular arcs. The effect of the central angle of a circular arc on dynamic behavior of vehicle-passenger was shown in previous paper (Yamamoto, et al, 2017). Fig.…”

“…The discontinuity of the curvature at a connection point makes highly precise control of the electric equipment mounted on vehicle very difficult. The authors developed a three-dimensional vehicle-passenger system in a previous paper (Yamamoto et al, 2017), and built an optimal running lane with a transition curve when vehicles turned at an intersection. The paper showed the influence of the curvature distribution on a vehicle and its occupants' dynamic behavior.…”

“…In this research, theoretical considerations are examined with regard to an optimal running lane in which a multiple clothoid curve (Yamamoto et al, 2017) is applied as a transition curve at the connection point. This point is located between a straight line and a circle, a circular arc and a circular arc, and a straight line and a straight line.…”

Experimental Study on Different Types of Curves for Ride Comfort in Automated Vehicles

“…We employed a clothoid because the enables smooth steering control as indicated in several studies [41][42][43][44]. Consequently, we considered one hypothesis regarding comfort, which is that the clothoid curve is better for driving comfort.…”