| 摘要 |
PROBLEM TO BE SOLVED: To accurately prevent a grip from being a lost state, regardless of a steer state, by highly accurately detecting a tire grip state. SOLUTION: A SAT (Self Aligning Torque) computation value SATa is calculated based on assist torque Tm, etc. A SAT estimated value SATb actually generated based on lateral force is estimated. A grip loss degree g is calculated from a difference between these values. The steer state of a vehicle is decided, and a torque correction valueΔT<SB>US</SB>orΔT<SB>OS</SB>which becomes larger as the grip loss degree g is larger from the grip loss degree g and the steer state, is larger in an over steer state than that in an under steer state and starts a correction at a faster stage is set. A current command value Itv is corrected by subtracting the equivalent torque correction valueΔT<SB>US</SB>orΔT<SB>OS</SB>from the current command value Itv according to steering torque T and vehicle speed V. The corrected current command value Itv is taken as a steering assist command value Im. Based on the steering assist command value Im, an electric motor 12 is driven. COPYRIGHT: (C)2009,JPO&INPIT |
