Vehicle Chassis Integrated Control Based on Multimodel and Multilevel Hierarchical Control

Table 1

Vehicle state identification and stability criterion.

Conditions	Driving state		Stability	Code
𝛿<𝛿𝐿; Linear; mode	𝜓̇≤𝜓̇𝑡; 𝑎𝑥<𝑎𝑥𝑡	Straight	Yes	1
	𝜓̇≤𝜓̇𝑡; 𝑎𝑥≥𝑎𝑥𝑡	braking	Yes	2
	𝜓̇>𝜓̇𝑡	Lateral	No	3
𝛿≥𝛿𝐿; Steering condition	𝑢^2ch>0; 𝑢^2ch≥𝑢^2; (1<1+𝑢^2/𝑢^2ch≤2)	Small understeer	Yes	4
	𝑢^2ch>0; 0<𝑢^2ch<𝑢^2; (1+𝑢^2/𝑢^2ch>2)	Major understeer	No	5
	𝑢^2ch<0; 𝑢^2ch≥𝑢^2; (0≤1+𝑢^2/𝑢^2ch≤1)	Small oversteer	Yes	6
	𝑢^2ch<0; 𝑢^2ch<𝑢^2; (1+𝑢^2/𝑢^2ch<0)	Heated steering	No	7