System for controlling motor vehicle components according to the “drive-by-wire” principle

• US 6,650,979 B1
• Filed: 07/19/2002
• Issued: 11/18/2003
• Est. Priority Date: 09/25/1999
• Status: Expired due to Fees

• Current Assignee: Volkswagen AG
• Original Assignee: Volkswagen AG
• Inventors: Kreft, Joerg
• Primary Examiner(s): Marc-Coleman, Marthe Y.
• Application Number:
  US10/088,967
• Time in Patent Office: 487 Days
• Field of Search: 701/41, 701/70, 701/71, 303/140, 303/147, 303/20, 303/122.04, 188/158
• US Class Current: 701/41
• CPC Class Codes: B60T 13/686 in hydraulic systems or parts thereof
• CPC Class Codes: B60T 13/745 acting on a hydraulic system, e.g. a master cylinder
• CPC Class Codes: B60T 17/22 Devices for monitoring or checking brake systems; Signal devices
• CPC Class Codes: B60T 8/326 Hydraulic systems
• CPC Class Codes: B60T 8/328 Systems sharing components with other fluid systems onboard the vehicle
• CPC Class Codes: B62D 5/003 Backup systems, e.g. for manual steering B62D5/30 takes precedence
• CPC Class Codes: B62D 5/0481 monitoring the steering system, e.g. failures
• CPC Class Codes: B62D 5/065 characterised by specially adapted means for varying pressurised fluid supply based on need, e.g. on-demand, variable assist
• CPC Class Codes: B62D 5/30 Safety devices, e.g. alternate emergency power supply or transmission means to ensure steering upon failure of the primary steering means

Abstract

A “drive by wire” system reverts to a safe condition if an error affecting safely is identified. The system includes a steerable wheel, a steering device, and control computers linked to sensor(s) which detect movement and position of the steering wheel. The system includes positioning devices mechanically coupled to the steerable wheel and controllable by one of the control computers and majority voting units. The positioning unit is actively controllable by its assigned control computer. The control computers determine their own condition and the condition of the system by model-based calculations, using measured values detected by the sensors and switch over from, the currently active control computer to the control computer assigned to the other positioning unit, if deviations from the model forecasts in a majority of the control computers are indicated.

Claims

1. A system for controlling vehicle components, comprising:

at least one steerable wheel;

one of a steering wheel and a steering device;

an odd number of more than one intercommunicating control computers, each connected to at least one first sensor configured to detect one of a movement and an actuation of the one of the steering wheel and the steering device and connected to at least one second sensor configured to detect a position of the at least one steerable wheel;

a first actuator;

a first voter-basis discriminator assigned to the first actuator;

a second actuator; and

a second voter-basis discriminator assigned to the second actuator;

wherein, in accordance with model calculations and measured values acquired by the first sensor and the second sensor, each of the control computers is configured to ascertain a corresponding state and a state of the system and, in each case, to effect a switchover from an active control computer to a control computer assigned to another actuator, if the system function shows deviations from model expectations of a majority of the control computers;

wherein each of the control computers is configured to transmit a first signal to the first voter-basis discriminator and a second signal different from the first signal to the second voter-basis discriminator, the first actuator and the second actuator mechanically and respectively coupled to the at least one steerable wheel, the first actuator and the second actuator configured to be controlled by one of the control computers, and one of the first actuator and the second actuator, corresponding to the voter-basis discriminator that receives the first signal from a majority of the control computers, configured to be actively controlled by a corresponding control computer 15.

2. The system according to claim 1, wherein the control computers are configured to intercommunicate via a CAN bus.

3. The system according to claim 1, wherein the control computers are configured to determine a current steering-wheel angle in accordance with the first sensors.

4. The system according to claim 1, wherein each actuator includes a hydraulic control unit having a double-acting steering cylinder.

5. The system according to claim 4, further comprising a steering bypass valve configured to interconnect two cylinder chambers of the double-acting steering cylinder.

6. The system according to claim 4, further comprising a proportional valve configured to adjust specific pressure in two cylinder chambers of the double-acting steering cylinder.

7. The system according to claim 4, further comprising a separate pressure sensor connected to each of two cylinder chambers of the double-acting steering cylinder.

8. The system according to claim 4, further comprising a pump assigned to the hydraulic control unit, the pump configured to provide supply pressure.

9. The system according to claim 8, wherein an outlet of the pump is connected to a pressure reservoir by a non-return valve.

10. The system according to claim 9, further comprising a branch, which includes a pump bypass valve and is configured to empty into a hydraulic-fluid tank, connected between the outlet of the pump and the non-return valve.

11. The system according to claim 8, further comprising at least one pressure sensor configured to detect the supply pressure, the control computer having active control configured to limit the pump as a function of the detected pressure value.

12. The according to claim 4, further comprising a steering-torque motor connected to the steering wheel, one of the control computers configured to control the steering-torque motor to simulate a restoring torque, a restoring torque to be generated at the steering wheel by the steering-torque motor calculated in accordance with a pressure difference between two cylinder chambers of the double-acting steering cylinder.

13. The system according to claim 1, further comprising a steering-torque motor connected to the steering wheel, one of the control computers configured to control the steering-torque motor to simulate a restoring torque.

14. The system according to claim 1, further comprising an independent power-supply device corresponding to the control computers and the first and second sensors.

15. The system according to claim 1, wherein the control computers are configured to implement a routine configured to allow a first controlling control computer to formulate and transmit a switchover request to other control computers, whereby the other control computers change the signals received by the voting-basis discriminators, so that a different control-enabled control computer assumes control in the system, by then controlling the actuator assigned to the first controlling computer.

16. The system according to claim 15, wherein the brake-pedal mechanism includes at least one spring configured to simulate a counterpressure of brake hydraulics.

17. The system according to claim 1, further comprising:

a brake-pedal mechanism;

at least one brake circuit including at least one first wheel-brake cylinder, at least one second wheel-brake cylinder and a hydraulic control unit;

at least one third sensor corresponding to the odd number of more than one control computers, each of the at least one third sensor configured to detect a position of the brake pedal and connected to one of the control computers, and each of the at least one third sensor assigned a different control computer by which the corresponding brake circuit is controllable according to a brake by wire principle.

18. The system according to claim 17, wherein the at least one brake circuit includes two brake circuits that are independent of each other, each brake circuit including two wheel-brake cylinders, of which a first wheel-brake cylinder is assigned to a front wheel and a second wheel-brake cylinder is assigned to a rear wheel on an opposite side of the vehicle.

19. The system according to claim 18, wherein cylinder chambers of the two wheel-brake cylinders of a brake circuit are connectable, via a separate proportional valve, to one of a pump and a return line connected to a hydraulic-fluid tank.

20. The system according to claim 18, further comprising a steering bypass valve configured to interconnect cylinder chambers of the two wheel-brake cylinders of a brake circuit.

21. The system according to claim 15, further comprising a separate pressure sensor connected to cylinder chamber of each wheel-brake cylinder.

22. The system according to claim 1, wherein the system is configured to control the vehicle components according to a drive by wire principle.