Method for determining variables characterizing vehicle handling

• US 5,557,520 A
• Filed: 07/29/1994
• Issued: 09/17/1996
• Est. Priority Date: 07/29/1993
• Status: Expired due to Term

• Current Assignee: Daimler AG (Mercedes-Benz Group AG)
• Original Assignee: Daimler-Benz AG (Mercedes-Benz Group AG)
• Inventors: Boettiger, Friedrich, Zomotor, Zoltan, Suissa, Avshalom
• Primary Examiner(s): ZANELLI, MICHAEL J
• Application Number:
  US08/283,297
• Time in Patent Office: 781 Days
• Field of Search: 364/424.01, 364/426.01, 364/424.05, 364/434
• US Class Current: 701/29
• CPC Class Codes: B60T 2230/02 Side slip angle, attitude angle, floating angle, drift angle
• CPC Class Codes: B60T 2270/86 Optimizing braking by using ESP vehicle or tire model
• CPC Class Codes: B60T 8/172 Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters B60T8/17551 takes precedence
• CPC Class Codes: B60T 8/17551 determining control parameters related to vehicle stability used in the regulation, e.g. by calculations involving measured or detected parameters
• CPC Class Codes: B62D 6/00 Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits means for initiating a change in direction B62D1/00; steering valves B62D5/06; combined with means for inclining the vehicle body or wheels on bends B62D9/00
• CPC Class Codes: B62D 7/159 characterised by computing methods or stabilisation processes or systems, e.g. responding to yaw rate, lateral wind, load, road condition
• CPC Class Codes: G05D 1/0891 specially adapted for land vehicles

Abstract

A method for determining variables characterizing vehicle handling is provided, in particular the attitude angle. Signals of measured variables are fed to a computing device. At least the attitude angle is determined in the computing device using equations of motion and using a two-track model of the vehicle.

Claims

1. A method for determining variables which represent handling characteristics of a vehicle having wheels, said method comprising the steps of:

feeding signals from the vehicle to a computing device, said signals representing measured values of a vehicle longitudinal velocity (v_x), a vehicle longitudinal acceleration (a_x), a vehicle lateral acceleration (a_y), and a vehicle yaw velocity (Ψ

);

using state equations of motion in the computing device to determine said variables characterizing vehicle handling;

determining a side slip angle (β

) in the computing device as one of said variables characterizing vehicle handling;

feeding at least further signals from the vehicle representing the measured variables of a steering angle (δ

), and a wheel speed (ω

) of individual ones of said wheels to the computing device;

using in the computing device at least one measurement equation based on a vehicle model;

using at least an inclination angle (Φ

) of a roadway with respect to a plane as a state variable in said measurement equation; and

outputting signals from the computing device for said variables characterizing vehicle handling, including said side slip angle for the vehicle.

2. A method according to claim 1, wherein an expression for an adhesion coefficient (μ

) between a vehicle wheel and the roadway is used as a further state variable, and wherein the further state variable is used as an estimate for the adhesion coefficient (μ

) in said at least one measurement equation.

3. A method according to claim 2, wherein the adhesion coefficient (μ

) is quasistationary ( μ

=0).

4. A method according to claim 1, wherein said step of feeding signals to the computing device includes feeding the computing device with signals representing measured values of a vehicle yaw acceleration ( Ψ

) and a vehicle roll angle velocity.

5. A method according to claim 4, wherein as a further state equation of motion based on a vehicle model, a time derivative of an inclination error (e) forms the vehicle roll angle velocity.

6. A method according to claim 4, wherein the vehicle yaw acceleration is determined by measuring two lateral accelerations (a_y1,a_y2) by two sensors arranged spaced apart from each other in a vehicle longitudinal direction.

7. A method according to claim 1, further comprising the step of transforming the state equations of motion and the measurement equations into an observer standard form.

8. A method according to claim 7, wherein said transformation step determines an observer amplification using Kalman filtering.

9. A method according to claim 1, wherein the measurement equations are derived from a four-wheel model of the vehicle.

10. A system to determine variables representing handling characteristics of a vehicle having wheels, the system comprising:

a vehicle longitudinal velocity sensor providing a vehicle longitudinal velocity output signal (v_x);

a vehicle longitudinal acceleration sensor providing a vehicle longitudinal acceleration output signal (a_x);

a vehicle lateral acceleration sensor providing a vehicle lateral acceleration output signal (a_y);

a vehicle yaw velocity sensor providing a vehicle yaw velocity output signal (Ψ

);

a steering angle sensor providing a steering angle output signal (δ

);

wheel speed sensors providing wheel speed output signals (ω

) for individual ones of said wheels of the vehicle;

a computing device which receives as inputs said vehicle longitudinal velocity signal (v_x), said vehicle longitudinal acceleration signal (a_x), said vehicle lateral acceleration signal (a_y), said vehicle yaw velocity signal (Ψ

), said steering angle signal (δ

), and said wheel speed signals (ω

), said computing device being programmed to perform the following steps;

determining said variables representing handling characteristics of the vehicle, including a side slip angle (β

) as one of said variables, using state equations of motion and at least one measurement equation based on a vehicle model, wherein an inclination angle (Φ

) of a roadway with respect to a plane is used as a state variable in the measurement equation; and

wherein said computing device outputs the side slip angle (β

).