Driving support control apparatus using electric power steering mechanism
A driving support control apparatus using an electric power steering mechanism that improves followability to a target track and safety of steering operation by adapting information of a steering torque to a driver's characteristic on the basis of conditions for enhancing predictability of a vehicle track. The driving support control apparatus includes: a SAT estimating section that estimates a self-aligning torque; a SAT transfer characteristic control section that corrects the self-aligning torque in order to make a time constant of a self-aligning torque transfer characteristic equal to a desired value, and compensates the steering torque; a disturbance sensitivity control section that suppresses a disturbance included by the self-aligning torque, and compensates the steering torque; and a vehicle characteristic compensation control section that compensates the steering torque in accordance with an actual steering angle so that a vehicle characteristic becomes a primary delay characteristic.
1. A driving support control apparatus using an electric power steering mechanism that calculates a current command value based on at least a steering torque, drives a motor based on said current command value, and assists and controls a steering system, comprising:
a SAT estimating section that estimates a self-aligning torque;
a SAT transfer characteristic control section that corrects said self-aligning torque in order to make a time constant of a self-aligning torque transfer characteristic equal to a desired value, compensates said steering torque in accordance with a corrected self-aligning torque, and outputs a compensated steering torque as a first compensated steering torque;
a disturbance sensitivity control section that suppresses a disturbance included by said self-aligning torque, compensates said first compensated steering torque in accordance with a self-aligning torque obtained by suppressing said disturbance, and outputs a compensated first compensated steering torque as a second compensated steering torque; and
a vehicle characteristic compensation control section that compensates said second compensated steering torque in accordance with an actual steering angle that is detected so that a vehicle characteristic from said actual steering angle to a yaw rate becomes a primary delay characteristic.
2. The driving support control apparatus using the electric power steering mechanism according to claim 1 , wherein
said vehicle characteristic compensation control section compensates said second compensated steering torque by using a characteristic Cf(s) providing said vehicle characteristic with damping, and said characteristic Cf(s) has been adjusted so that a damping factor of said yaw rate changing depending on a natural frequency of said electric power steering mechanism approximates a highest damping factor.
3. The driving support control apparatus using the electric power steering mechanism according to claim 2 , wherein
said characteristic Cf(s) has been adjusted so that said damping factor of said yaw rate is about 0.8 and a yaw rate natural frequency is between about 2 Hz and about 4 Hz.
4. The driving support control apparatus using the electric power steering mechanism according to claim 1 , wherein
said SAT transfer characteristic control section is configured as a disturbance observer.
5. The driving support control apparatus using the electric power steering mechanism according to claim 2 , wherein
said SAT transfer characteristic control section is configured as a disturbance observer.
6. The driving support control apparatus using the electric power steering mechanism according to claim 3 , wherein
said SAT transfer characteristic control section is configured as a disturbance observer.
7. The driving support control apparatus using the electric power steering mechanism according to claim 4 , wherein
said SAT transfer characteristic control section compensates said steering torque by using a transfer characteristic defined by said desired time constant.
8. The driving support control apparatus using the electric power steering mechanism according to claim 5 , wherein
said SAT transfer characteristic control section compensates said steering torque by using a transfer characteristic defined by said desired time constant.
9. The driving support control apparatus using the electric power steering mechanism according to claim 1 , wherein
said disturbance sensitivity control section comprises a controller for each disturbance that is suppressed.
10. The driving support control apparatus using the electric power steering mechanism according to claim 2 , wherein
said disturbance sensitivity control section comprises a controller for each disturbance that is suppressed.
11. The driving support control apparatus using the electric power steering mechanism according to claim 3 , wherein
said disturbance sensitivity control section comprises a controller for each disturbance that is suppressed.
12. The driving support control apparatus using the electric power steering mechanism according to claim 4 , wherein
said disturbance sensitivity control section comprises a controller for each disturbance that is suppressed.
13. The driving support control apparatus using the electric power steering mechanism according to claim 7 , wherein
said disturbance sensitivity control section comprises a controller for each disturbance that is suppressed.
14. The driving support control apparatus using the electric power steering mechanism according to claim 9 , wherein
one of said disturbances that said disturbance sensitivity control section suppresses is a small-amplitude disturbance occurring by a small-amplitude torque vibration, and said controller for said small-amplitude disturbance is configured as a structural damping model.
15. The driving support control apparatus using the electric power steering mechanism according to claim 10 , wherein
one of said disturbances that said disturbance sensitivity control section suppresses is a small-amplitude disturbance occurring by a small-amplitude torque vibration, and said controller for said small-amplitude disturbance is configured as a structural damping model.
16. The driving support control apparatus using the electric power steering mechanism according to claim 9 , wherein
one of said disturbances that said disturbance sensitivity control section suppresses is a resonance point disturbance excited at a resonance point in a longitudinal direction of a suspension, and said controller for said resonance point disturbance is configured as a disturbance observer.
17. The driving support control apparatus using the electric power steering mechanism according to claim 10 , wherein
one of said disturbances that said disturbance sensitivity control section suppresses is a resonance point disturbance excited at a resonance point in a longitudinal direction of a suspension, and said controller for said resonance point disturbance is configured as a disturbance observer.
18. The driving support control apparatus using the electric power steering mechanism according to claim 9 , wherein
one of said disturbances that said disturbance sensitivity control section suppresses is a cant disturbance occurring by a road cant, and said controller for said cant disturbance performs detection of a straight running state of a vehicle and a offset correction of said self-aligning torque.
19. The driving support control apparatus using the electric power steering mechanism according to claim 10 , wherein
one of said disturbances that said disturbance sensitivity control section suppresses is a cant disturbance occurring by a road cant, and said controller for said cant disturbance performs detection of a straight running state of a vehicle and a offset correction of said self-aligning torque.