Sensor system, vehicle control system and driver information system for vehicle safety

• US 8,751,091 B2
• Filed: 03/09/2009
• Issued: 06/10/2014
• Est. Priority Date: 03/13/2008
• Status: Active Grant

• Current Assignee: TRUMPF Photonic Components GmbH (TRUMPF SE + Co. KG)
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Moench, Holger, Carpaij, Mark, Comberg, Albert
• Primary Examiner(s): Refai, Ramsey
• Application Number:
  US12/919,257
• Publication Number:
  US 20110035093A1
• Time in Patent Office: 1,919 Days
• Field of Search: 701/29.1
• US Class Current: 701/29.1
• CPC Class Codes: G01P 3/366 by using diffraction of light for measuring speed of fluids G01P5/26
• CPC Class Codes: G01S 17/58 Velocity or trajectory determination systems; Sense-of-movement determination systems
• CPC Class Codes: G01S 17/88 Lidar systems specially adapted for specific applications
• CPC Class Codes: G01S 7/491 Details of non-pulse systems
• CPC Class Codes: G01S 7/4911 Transmitters
• CPC Class Codes: G01S 7/4916 using self-mixing in the laser cavity

Abstract

A sensor system is described, using self-mixing laser sensors (10) and an analyzer circuit (30) in order to determine the velocity of a vehicle, such as a car, and the rotational velocity of a wheel (20) of the car. Deviations between the velocity of the vehicle and the rotational velocity of the wheel (20) can be used to determine sliding of the wheel (20) and, finally, the traction or, more specifically, the coefficient of driving friction between the wheel (20) and the surface the car is driving on. Furthermore, a vehicle control system is described, initiating test accelerations of a wheel (20) by means of a control circuit (50) and control means (300, 400) in order to determine the coefficient of driving friction during driving. The test accelerations initiate short periods of sliding of the wheel (20) and the sliding is detected by means of the sensor system.

Claims

1. A sensor system comprising:

at least one laser sensor working with self-mixing interference comprising a plurality of Vertical Cavity Surface Emitting Laser sources adapted to emit laser radiation in essentially the same direction and a corresponding plurality of integrated photodiodes adapted to detect backscattered light from the emitted laser radiation, respectively;

at least one rotation sensor; and

an analyzer circuit,

wherein the at least one laser sensor is adapted to generate first measurement data using self-mixing interference resulting from a first velocity component of a vehicle, the rotation sensor is adapted to generate rotational measurement data resulting from a first rotational velocity of a first wheel of the vehicle, and the analyzer circuit is adapted to receive the first measurement data generated by the at least one laser sensor and rotational measurement data generated the rotation sensor, and is further adapted to determine the first velocity component of the vehicle and the first rotational velocity of the first wheel of the vehicle using the first measurement data and the rotational measurement data.

2. The sensor system according to claim 1, wherein the rotation sensor is a laser sensor working with self-mixing interference.

3. The sensor system according to claim 1, further comprising:

a control element configured to vary at least one of a focal point of the laser radiation, an intensity of the laser radiation and a direction of the laser radiation emitted by the Vertical Cavity Surface Emitting Laser diodes in different ways.

4. The sensor system according to claim 1, wherein the at least one laser sensor is further adapted to generate distance measurement data resulting from a first distance between a mounting location of the laser sensor and a surface on which the vehicle is driving and at least a second distance between the mounting location of the laser sensor and the surface on which the vehicle is driving, or between the mounting location of the laser sensor and the surface of the first wheel of the vehicle, the first distance being different from the second distance and the analyzer circuit being adapted to determine the first distance and the second distance.

5. A vehicle control system comprising:

the sensor system according to claim 1; and

a control circuit adapted to receive data from the analyzer circuit and to activate at least one vehicle system controller taking the data received from the analyzer circuit into account.

6. The vehicle control system according to claim 5, wherein the control circuit is adapted to activate the at least one vehicle system controller so as to initiate test accelerations of at least one first wheel of the vehicle independently of the data received from the analyzer circuit, and wherein the control circuit is further adapted to determine a maximum frictional force between at least the first wheel and a surface on which the vehicle is driving by analyzing the data received from the analyzer circuit.

7. The vehicle control system according to claim 6, wherein the control circuit is further adapted to determine a normal force between the first wheel and the surface on which the vehicle is driving, and to determine a coefficient of driving friction between the first wheel and the surface on which the vehicle is driving.

8. A system comprising:

the sensor system according to claim 1; and

a driver information system adapted to receive data from the sensor system and to supply at least one of optical and acoustical information based on the data received from the sensor system to a driver of the vehicle.

9. The system according to claim 8 further comprising:

the vehicle control system of claim 9, wherein the driver information system is adapted to receive data from the vehicle control system and is further adapted to supply at least one of optical and acoustical information based on the data received from the vehicle control system to a driver of the vehicle.

10. The sensor system according to claim 1, wherein the at least one laser sensor working with self-mixing interference comprises an array of Vertical Cavity Surface Emitting Laser diodes which are adapted to emit laser radiation in essentially the same direction.

11. A sensor system comprising:

at least one laser sensor working with self-mixing interference comprising a plurality of Vertical Cavity Surface Emitting Laser diodes which are adapted to emit laser radiation in essentially the same direction and to generate measurement data resulting from a first velocity component of a vehicle;

at least one rotation sensor adapted to generate measurement data resulting from a first rotational velocity of a first wheel of the vehicle; and

an analyzer circuit adapted to receive the measurement data generated by the at least one laser sensor and the at least one rotation sensor, and to determine the first velocity component of the vehicle and the first rotational velocity of the first wheel of the vehicle using the first measurement data and the rotational measurement data,

wherein the at least one laser sensor is further adapted to generate second measurement data with self-mixing interference resulting from a second velocity component of the vehicle different from the first velocity component, and the analyzer circuit is further adapted to determine the second velocity component of the vehicle using the second measurement data.

12. The sensor system according to claim 11, wherein the at least one laser sensor is further adapted to generate third measurement data with self-mixing interference resulting from a third velocity component of the vehicle different from the first velocity component and the second velocity component, and the analyzer circuit is further adapted to determine the third velocity component of the vehicle using the third measurement data.

13. The sensor system according to claim 12, wherein the analyzer circuit is further adapted to determine traction between at least the first wheel and a surface on which the vehicle is driving by analyzing the first rotational velocity in relation to at least one of the first velocity component, the second velocity component and the third velocity component of the vehicle.

14. A sensor system of a vehicle, the system comprising:

a first laser sensor comprising a first laser source configured to emit laser radiation and a first integrated detector configured to detect backscattered light from a surface on which the vehicle is driving, the laser sensor being configured to generate first measurement data, using self-mixing interference, resulting from as least one velocity component of the vehicle;

a second laser sensor comprising a second laser source configured to emit laser radiation and a second integrated detector configured to detect backscattered light from a surface of a wheel of the vehicle, the second laser sensor being configured to generate second measurement data, using self-mixing interference, resulting from a rotational velocity of the wheel of the vehicle; and

an analyzer circuit configured to receive the first and second measurement data generated by the first and second laser sensors, respectively, and to determine the at least one velocity component of the vehicle and the first rotational velocity of the first wheel of the vehicle.

15. The sensor of claim 14, wherein the laser sensor comprises a Vertical Cavity Surface Emitting Laser (VCSEL).

16. The sensor of claim 14, wherein the laser sensor comprises a Vertical Extended Cavity Surface Emitting Laser (VECSEL).