Electric power steering system
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorsTakahiro Okanoue, Takayuki Kifuku
Life of this patent
Estimating the term…
Abstract
To keep low the cross frequency of current feedback control and provide a good steering feeling, a first operation expression is selected when a difference ξ between a current instruction value computed based on a steering state of a steering wheel and a traveling state of a vehicle and a motor drive current value supplied from a battery to a motor for providing assist force to a system for transmitting power from the steering wheel to the wheels is larger than a predetermined value Th1, a second operation expression is selected when the difference ξ is smaller than the predetermined value Th1, and the difference ξ is corrected using the selected operation expression.
Claims20
An electric power steering system, wherein a difference between a current instruction value computed based on a steering state of a steering wheel and a traveling state of a vehicle and a motor drive current detection value supplied from a battery to a motor for providing assist force to a system for transmitting power from the steering wheel to the wheels is obtained, a first operation expression is selected when an absolute value of the difference is larger than a first predetermined value, a second operation expression is selected when the absolute value of the difference is smaller than a second predetermined value, the difference is corrected using the selected operation expressions and the current feedback control is carried out according to the corrected difference.
An electric power steering system for carrying out current feedback control by determining a difference between a current instruction value computed based on a steering state of a steering wheel and a traveling state of a vehicle and a motor drive current value supplied from a battery to a motor for providing assist force to a system for transmitting power from the steering wheel to the wheels, by determining a correction operation expression for correcting the gain for current feedback control system and carrying out current feedback control by correcting the gain of the current feedback control using the determined correction operation expression, wherein the difference is represented by I, a correction operation expression determined by this difference I is represented by A(I), and the correction operation expression A(I) satisfies ⅆ A ( I ) ⅆ I ≥ 0.
Dependencies are inferred from the claim text.