Research on Variable Transmission Ratio and Yaw Rate Control Strategy of Electric Forklift Steering-by-Wire System

Abstract

Comb ined with the trans mission ratio characteristics of fo rklift steering-by-wire (SBW) system, through the application of fu zzy control technology, the variable trans mission ratio function is designed based on the steering handle angle and vehicle speed, and simu lation analysis of sinusoidal steering is done at low-speed and high-speed. Simu lation results show that the fuzzy variable transmission ratio control can make forklift steering light & sensitive at lo w-speed and steering steady & heavy at high speed, also it can improve the operation stability and reduce the driver's load. Discuss the relationship between yaw rate and forklift handling stability, propose the yaw rate feedback control strategy based on the fuzzy variable t ransmission ratio control, and design a fuzzy self-adaptive PID controller. Simu lation results show that the SBW s ystem based on the fuzzy variable trans mission ratio control with yaw rate feedback can accurately and quickly t rack the desired yaw rate, and reduce or even eliminate the overshoot phenomenon, improve the forklift dynamic performance.

Electric Power Steering System Control Strategy Based on Robust H∞ Control for Electric Forklift

“…The yaw rate refers to the rotation of the vehicle about the vertical Z axis, which reflects the stability of the vehicle to some extent. Therefore, the observation target of the steering stability of electric power steering system is represented by the transient response characteristics of the yaw rate [26][27][28].…”