Method for estimating the longitudinal inclination of a roadway

• US 7,580,784 B2
• Filed: 10/26/2004
• Issued: 08/25/2009
• Est. Priority Date: 10/30/2003
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Schmidt, Mario, Grieser, Joerg
• Primary Examiner(s): Black; Thomas G
• Assistant Examiner(s): Olsen; Lin B
• Application Number:
  US10/974,903
• Publication Number:
  US 20050125107A1
• Time in Patent Office: 1,764 Days
• Field of Search: 701/1, 701/70
• US Class Current: 701/70
• CPC Class Codes: B60T 7/122 for locking of reverse movement
• CPC Class Codes: G01C 9/00 Measuring inclination, e.g. by clinometers, by levels

Abstract

A method and device for determining a longitudinal inclination variable representing the longitudinal inclination of a roadway, using a sensor “means” present in a motor vehicle, in which

• • a first unbraked driving state of the vehicle and
  • a second driving state of the motor vehicle in which at least one brake is actuated are considered; and
  • as a function thereof the variable representing the longitudinal inclination of the roadway is determined.

Claims

1. A method for determining a longitudinal inclination variable representing a longitudinal inclination of a roadway, using a sensor arrangement situated in a motor vehicle, the method comprising:

determining the variable representing the longitudinal inclination of the roadway as a function of a first unbraked driving state of the vehicle;

determining the variable representing longitudinal inclination of a second driving state of the vehicle in which at least one brake is actuated;

in the first driving state, determining a first difference between a vehicle longitudinal acceleration determined by a model and a vehicle longitudinal acceleration determined by evaluating wheel speed sensor signals;

in the second driving state, determining a second difference between a vehicle longitudinal acceleration determined by a model and a vehicle longitudinal acceleration determined by evaluating wheel speed sensor signals;

in the second driving state, determining a second difference between a vehicle longitudinal acceleration determined by a model and a vehicle longitudinal acceleration determined by evaluating wheel speed sensor signals;

determining a correction term as a function of the first and second differences;

determining a rough inclination variable representing a rough value of the longitudinal inclination of the roadway;

determining a value of the longitudinal inclination variable by adding a correction term to the rough inclination variable; and

determining the correction terms as a function of the first and second driving states.

2. The method according to claim 1, wherein the rough inclination variable is determined at least from wheel cylinder brake pressures, a drive torque of the vehicle, and a longitudinal acceleration of the vehicle determined using output signals from wheel speed sensors.

3. The method according to claim 1, further comprising:

continuously determining the longitudinal inclination variable during unbraked and braked driving states while keeping the correction term constant; and

redetermining and updating the correction term when a transition from a braked to an unbraked driving state occurs.

4. A method for determining a longitudinal inclination variable representing a longitudinal inclination of a roadway, using a sensor arrangement situated in a motor vehicle, the method comprising:

determining the variable representing the longitudinal inclination of the roadway as a function of a first unbraked driving state of the vehicle;

determining the variable representing the longitudinal inclination of a second driving state of the vehicle in which at least one brake is actuated;

in the first driving state, determining a first difference between a vehicle longitudinal acceleration determined by a model and a vehicle longitudinal acceleration determined by evaluating wheel speed sensor signals;

in the second driving state, determining a second difference between a vehicle longitudinal acceleration determined by a model and a vehicle longitudinal acceleration determined by evaluating wheel speed sensor signals;

determining a correction term as a function of the first and second differences; and

using a difference between the second difference and the first difference in determining the correction term.

5. A method for determining a longitudinal inclination variable representing a longitudinal inclination of a roadway, using a sensor arrangement situated in a motor vehicle, the method comprising:

determining the variable representing the longitudinal inclination of the roadway as a function of a first unbraked driving state of the vehicle;

determining the variable representing the longitudinal inclination of a second driving state of the vehicle in which at least one brake is actuated;

in the first driving state, determining a first difference between a vehicle longitudinal acceleration determined by a model and a vehicle longitudinal acceleration determined by evaluating wheel speed sensor signals;

in the second driving state, determining a second difference between a vehicle longitudinal acceleration determined by a model and a vehicle longitudinal acceleration determined by evaluating wheel speed sensor signals;

determining a correction term as a function of the first and second differences; and

using at least wheel cylinder brake pressure and a drive torque of the vehicle in determining a longitudinal acceleration of the vehicle in the first and second driving states, using a model.

6. A method for determining a longitudinal inclination variable representing a longitudinal inclination of a roadway, using a sensor arrangement situated in a motor vehicle, the method comprising:

determining the variable representing the longitudinal inclination of the roadway as a function of a first unbraked driving state of the vehicle;

determining the variable representing the longitudinal inclination of a second driving state of the vehicle in which at least one brake is actuated;

in the first driving state, determining a first difference between a vehicle longitudinal acceleration determined by a model and a vehicle longitudinal acceleration determined by evaluating wheel speed sensor signals;

in the second driving state, determining a second difference between a vehicle longitudinal acceleration determined by a model and a vehicle longitudinal acceleration determined by evaluating wheel speed sensor signals; and

determining a correction term as a function of the first and second differences;

wherein the first and second driving states are driving states which occur close to one another in time.

7. A device for determining a longitudinal inclination variable representing a longitudinal inclination of a roadway, using a sensor arrangement situated in a motor vehicle, the device comprising:

an evaluation device in which a first unbraked driving state of the vehicle and a second driving state of the vehicle, in which at least one brake is actuated, are considered;

an arrangement for determining the longitudinal inclination, in which the variable representing the longitudinal inclination of the roadway is determined as a function of output signals from the evaluation device and, in the first driving state, for determining a first difference between a vehicle longitudinal acceleration determined by a model and a vehicle longitudinal acceleration determined by evaluating wheel speed sensor signals, and in the second driving state, for determining a second difference between a vehicle longitudinal acceleration determined by a model and a vehicle longitudinal acceleration determined by evaluating wheel speed sensor signals, and for determining a correction term as a function of the first and second differences.