Device and method for estimating physical quantity and device and method for ABS control
First Claim
1. A physical quantity estimation device, comprising:
- wheel velocity detection means for detecting the velocity of a wheel and outputting a wheel velocity signal; and
physical quantity estimation means for identifying a damping ratio parameter of a physical model of a system having a tire and a suspension expressing unsprung resonance characteristics of a suspension-tire relationship in a longitudinal direction of a vehicle, the parameter being identified from the wheel velocity signal, and estimating a physical quantity relating to ease of slip between a road surface and a wheel from the identified parameter.
3 Assignments
0 Petitions
Accused Products
Abstract
A wheel velocity signal for each wheel detected by a wheel velocity sensor is input to a bandpass filter. Signals from frequency bands unrelated to the unsprung resonance are then removed from the wheel velocity signal and only signals from frequency bands related to the unsprung resonance are output. A road surface μ gradient estimation device uses an online identification method to identify an damping ratio of a second order resonance model similar to a suspension—tire resonance model from the signal output from the bandpass filter. The road surface μ gradient is then estimated from the identified damping ratio. The damping ratio of the second order resonance model corresponds to the road surface μ gradient in the following manner: when the damping ratio is identified as being small, the road surface μ gradient is estimated as being large; and when the road surface μ gradient is identified as being large, the damping ratio is estimated as being small.
17 Citations
14 Claims
-
1. A physical quantity estimation device, comprising:
-
wheel velocity detection means for detecting the velocity of a wheel and outputting a wheel velocity signal; and
physical quantity estimation means for identifying a damping ratio parameter of a physical model of a system having a tire and a suspension expressing unsprung resonance characteristics of a suspension-tire relationship in a longitudinal direction of a vehicle, the parameter being identified from the wheel velocity signal, and estimating a physical quantity relating to ease of slip between a road surface and a wheel from the identified parameter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
the physical quantity estimation device according to claim 1; and
control means for controlling braking pressure on the basis of a physical quantity estimated by the physical quantity estimation device.
-
-
9. The ABS control device according to claim 8, wherein the physical quantity relating to ease of slip between a road surface and a wheel is a road surface μ
- gradient and the control means controls the braking pressure so that the road surface μ
gradient is 0 or approximately 0.
- gradient and the control means controls the braking pressure so that the road surface μ
-
10. The ABS control device according to claim 8, wherein the control means increases the braking pressure in a ramp-shaped manner so that the braking pressure is adapted to a high μ
- road surface when the control means judges that the vehicle has traveled onto a high μ
road surface on the basis of the physical quantity.
- road surface when the control means judges that the vehicle has traveled onto a high μ
-
11. A physical quantity estimation method, comprising the steps of:
-
detecting a velocity of a wheel and outputting a wheel velocity signal;
identifying a damping ratio parameter of a physical model of a system having a tire and a suspension expressing unsprung resonance characteristics of a suspension-tire relationship in a longitudinal direction of a vehicle, the parameter being identified from the wheel velocity signal; and
estimating a physical quantity relating to ease of slip between a road surface and a wheel from the identified parameter. - View Dependent Claims (12, 13, 14)
-
Specification