Design and Optimization of Suspension and Steering System of Efficycle – Human Powered Hybrid Tricycle

Abstract

Suspension is a system of tires, springs, shock absorbers, and linkages that connects a vehicle’s chassis to its wheels and allows relative motion between the two. Steering is a mechanism that provides a direction to the vehicle, it basically consists of gears, shaft, joints, steering column, steering wheel, and furthermore. The main objective of this paper is to design a system of suspension and steering for a three-wheeled human-electric hybrid trike. A system of directly actuated double wishbone suspension system is chosen for the front and a pushrod actuated 2-link trailing arm suspension system for the rear. The steering system used is a type of Single tie rod and drag link system. A knuckle-to-knuckle drag link provides continuity to the wheels and a tie rod to the bell crank provides steering rotation. This paper also talks about the single nut hub-shaft system which is being used in the front suspension system. Based on the research using various input parameters, the inboard and outboard suspension hardpoints are decided to maximize the tire contact patch at every vehicular motion (mainly during body roll). Forces and stresses are calculated with the help of Free Body Diagrams (FBD) and Multi-Body Dynamics (MBD) software LOTUS Shark. The paper discusses the calculations regarding the roll and ride rates and for the custom springs of specific stiffness used in front and rear shock absorbers and the variation of roll steer and bump steer on changing various parameters of the steering system. Key points also include the procedure of selections of various types of bearings, rod ends, and bolts. This paper also talks about laser-cut jigsaw uprights that are used in the front wheel assembly. The finite element method was used to analyze the designs using DS Solidworks and Ansys Workbench. Static structural and explicit dynamics analysis was performed on the wheel assembly components both individually and assembled