Electric power steering apparatus and control apparatus determining parameter set to the same
AssigneeNsk Ltd.
InventorTakahiro TSUBAKI
Life of this patent
Estimating the term…
Abstract
An electric power steering apparatus that achieves a desired steering characteristic in minutely steering at on-center, suppresses frictional feeling, and improves linear steering feeling at on-center, and a control apparatus that determines a parameter. The apparatus calculates a current command value by using an assist map related to a steering torque and a vehicle speed, drives a motor based on the current command value, and assists and controls a steering system.
Claims19
1-15. (canceled)
An electric power steering apparatus that calculates a current command value by using an assist map defining a characteristic of said current command value to a steering torque depending on a vehicle speed, drives a motor based on said current command value, and assists and controls a steering system comprising a torsion bar in a column shaft, comprising:
- a function of detecting a steering wheel angle and a column angle as steering angle information;
- and
- a SAT compensating-cum-virtual spring compensating section that calculates a SAT compensation-cum-virtual spring torque corresponding to said column angle or said steering wheel angle based on both said column angle or said steering wheel angle and said vehicle speed by using a SAT compensation-cum-virtual spring constant being vehicle speed sensitive, and outputs a compensation signal to which said SAT compensation-cum-virtual spring torque is converted in accordance with a current conversion coefficient;
- wherein an inclination Kmap′ from an origin of said assist map can be changed;
- and
- wherein said electric power steering apparatus compensates said current command value in accordance with said compensation signal, and gets a desired characteristic of on-center feeling.
A control apparatus for controlling an electric power steering apparatus that assists and controls a steering system comprising a torsion bar in a column shaft by using an assist map defining a characteristic of said current command value to a steering torque depending on a vehicle speed, comprising:
- a control parameter calculating section that calculates a SAT compensation-cum-virtual spring coefficient set to a SAT compensating-cum-virtual spring compensating section that said electric power steering apparatus comprises and an initial inclination set to said assist map, said SAT compensating-cum-virtual spring compensating section outputting a compensation signal to which a SAT compensation-cum-virtual spring torque calculated based on steering angle information and said vehicle speed is converted in accordance with a current conversion coefficient.
Dependencies are inferred from the claim text.