System for monitoring the course and for controlling the braking of a freely movable vehicle, particularly an inductively steered vehicle, and vehicle with such a system

• US 4,437,533 A
• Filed: 01/12/1982
• Issued: 03/20/1984
• Est. Priority Date: 03/18/1981
• Status: Expired due to Term

• Current Assignee: Jungheinrich Unternehmensverwaltung GmbH
• Original Assignee: Jungheinrich Unternehmensverwaltung KG
• Inventors: Klinger, Gottfried, Bierkarre, Hartwig, Radeloff, Jurgen, Rust, Bernd-Hendrik
• Primary Examiner(s): Mitchell, David M.
• Assistant Examiner(s): McCarthy, Joseph
• Application Number:
  US06/338,904
• Time in Patent Office: 798 Days
• Field of Search: 180/168, 318/587, 364/450
• US Class Current: 180/168
• CPC Class Codes: B60K 31/0066 responsive to vehicle path curvature
• CPC Class Codes: B60T 2201/08 Lane monitoring; Lane Keeping Systems
• CPC Class Codes: B60T 2201/083 using active brake actuation
• CPC Class Codes: B60T 2201/087 using active steering actuation
• CPC Class Codes: B60T 7/18 operated by wayside apparatus
• CPC Class Codes: B62D 1/28 non-mechanical , e.g. following a line or other known markers
• CPC Class Codes: G05D 1/0265 using buried wires

Abstract

A system for monitoring the course and braking means of a vehicle are provided, which is freely movable and particularly inductively steered. The vehicles comprise drive means and at least one steerable driven wheel, braking means, and a sensor for scanning a guideline. The system comprises an arrangement (25, 27), in which an emergency braking operation for stopping the vehicle within an emergency stopping distance is generated in dependence on a signal which corresponds to the angle between the longitudinal axis of the vehicle and the guideline, and another signal, which corresponds to the lateral departure of the longitudinal center line of the vehicle adjacent to the sensor from the guideline. The emergency stopping distance is shorter than the distance which the vehicle would travel to collide with an obstacle. Limiting values for a maximum or changing steering angle, the contour of the vehicle, the speed of travel and the braking distance under maximum load. The arrangement with its input and output terminals constitutes a self-contained module. A vehicle comprising such an arrangement is also provided.

Claims

1. In a circuit arrangement for initiating an emergency braking operation of a vehicle traveling along a guideline which extends at the center of a path defined by obstacles on at least one side, which vehicle comprises a steerable driven wheel, means defining a maximum steering angle for said driven wheel, travel drive means for driving said driven wheel, braking means arranged to effect an emergency braking of said vehicle within a predetermined maximum emergency stopping distance in response to the delivery of an emergency braking signal to said braking means, and a sensor which has first and second sensor output terminals and is operable to deliver at said first sensor output terminal an angular misalignment signal representing the angle between the longitudinal axis of the vehicle and said guideline and to deliver at said second sensor output terminal an actual departure signal representing the actual lateral departure of a predetermined point of the longitudinal center line of the vehicle from said guideline,

the improvement residing in that said circuit arrangement comprises

a processor having a first input terminal adapted to be connected to said first sensor output terminal, a second input terminal adapted to be connected to said second sensor output terminal, a third input terminal, and a constant-defining circuit defining a constant which depends on the contour of said vehicle in plan view and on said maximum emergency stopping distance,

a maximum departure signal generator connected to said third input terminal and operable to deliver to said third input terminal a maximum departure signal representing a maximum lateral departure of a predetermined point on said longitudinal center line from said guideline in dependence on said maximum steering angle and the width of said path of travel

said processor being operable to compute a maximum permissible lateral departure of said predetermined point of said longitudinal center line from said guideline in dependence on said actual lateral departure signal, said maximum departure signal, said angular misalignment signal, and said constant, and to deliver to said braking means said emergency signal when said maximum permissible lateral departure exceeds said actual lateral departure by less than a predetermined value.

2. The improvement set forth in claim 1, as applied to circuit arrangement for initiating an emergency braking operation of a vehicle which comprises a steering mechanism for steering said driven wheel in dependence on said angular misalignment signal and said actual lateral departure signal.

3. The improvement set forth in claim 1, wherein

said processor comprises a processing circuit which is connected to said first processor input terminal and includes said constant-defining circuit and is operable to process said angular misalignment signal in dependence on said constant and

said processor is operable to compute said maximum permissible lateral departure in dependence on the output of said processing circuit.

4. The improvement set forth in claim 1, wherein said processor comprises

an adding circuit which on its input side is connected to said second and third processor input terminals and said processing circuit and operable to generate a voltage signal representing the difference between said maximum permissible lateral departure and said actual lateral departure, and

a comparator for comparing said difference signal with a predetermined reference voltage and

for delivering to said braking means said emergency braking signal when said reference voltage exceeds said voltage signal.

5. The improvement set forth in claim 4, wherein

said processor comprises four of said adding circuits which are connected in parallel to said second processor input terminal, four of said third processor input terminals associated with respective ones of said adding circuits, four of said processing circuits associated with respective ones of said adding circuits, and four of said comparators associated with respective ones of said adding circuits,

four of said maximum lateral departure signal generators are provided, which are connected to respective ones of said third processor input terminals, and

a combining circuit is provided for delivering said emergency braking signal from said comparators to said braking means.

6. The improvement set forth in claim 5, wherein said combining circuit comprises a relay circuit.

7. The improvement set forth in claim 5, wherein said combining circuit comprises a gate.

8. The improvement set forth in claim 7, wherein said gate comprises an OR gate.

9. The improvement set forth in claim 5, in which an adjustable reference voltage generator is connected to each of said comparators and adapted to apply the adjustable predetermined reference voltage to said comparator.

10. The improvement set forth in claim 4, in which said comparator comprises a limiting diode which defines said predetermined reference voltage and is adapted to deliver to said braking means said emergency braking signal when said reference voltage exceeds said voltage signal.

11. The improvement set forth in claim 3, wherein said processing circuit comprises a linear operational amplifier.

12. The improvement set forth in claim 1, wherein said maximum lateral departure signal generator comprises a memory for storing said maximum steering angle.

13. The improvement set forth in claim 1, wherein

said processor has a fourth processor input terminal,

an actual steering angle signal generator is connected to said fourth processor input terminal and adapted to deliver to said processor via said fourth processor input terminal an additional signal, which depends on the actual steering angle of said vehicle, and

said processor is operable to compute said maximum permissible lateral departure of said predetermined point of said longitudinal center line from said vehicle in dependence on said additional signal.

14. The improvement set forth in claim 1, wherein said constant-defining circuit is adjustable to define an adjustable constant.

15. The improvement set forth in claim 1, wherein said circuit arrangement is comprised in a module which is adapted to be detachably mounted in a vehicle.

16. The improvement set forth in claim 1, as applied to a vehicle wherein said sensor comprises two transducer arrays, which are spaced apart along said vehicle, and is operable to generate said actual lateral departure signal in dependence on the lateral departure of said longitudinal center line at one of said transducer arrays from said guideline and to generate said angular misalignment signal in dependence on the distance between said transducer arrays and the lateral departure of said longitudinal center line at each of said transducer arrays from said guideline.

17. The improvement set forth in claim 1, wherein said maximum lateral departure signal generator is operable to deliver to said third input terminal a maximum departure voltage signal which is proportional to a maximum lateral departure of a predetermined point on said longitudinal center line from said guideline in dependence on said maximum steering angle.

18. In a vehicle travelling along a guideline which extends at the center of a path defined by obstacles on at least one side, which vehicle comprises a steerable driven wheel, means defining a maximum steering angle for said driven wheel, travel drive means for driving said driven wheel, braking means arranged to effect an emergency braking of said vehicle within a predetermined maximum emergency stopping distance in response to the delivery of an emergency braking signal to said braking means, a sensor which has first and second sensor output terminals and is operable to deliver at said first sensor output terminal an angular misalignment signal representing the angle between the longitudinal axis of the vehicle and said guideline and to deliver at said second sensor output terminal an actual departure signal representing the actual lateral departure of a predetermined point of the longitudinal center line of the vehicle from said guideline, and a circuit arrangement for initiating an emergency braking operation of said braking means in dependence on said angular misalignment signal and said actual angular departure signal,

the improvement residing in that said circuit arrangement comprises

a processor having a first input terminal adapted to be connected to said first sensor output terminal, a second input terminal adapted to be connected to said second sensor output terminal, a third input terminal, and a constant-defining circuit defining a constant which depends on the contour of said vehicle in plan view and on said maximum emergency stopping distance

a maximum departure signal generator connected to said third input terminal and operable to deliver to said third input terminal a maximum departure signal representing a maximum lateral departure of a pedetermined point on said longitudinal center line from said guideline in dependence on said maximum steering angle and the width of said path of travel,

said processor being operable to compute a maximum permissible lateral departure of said predetermined point of said longitudinal center line from said guideline in dependence on said actual lateral departure signal, said maximum departure signal, said angular misalignment signal and said constant, and connected to said braking means and adapted to deliver to said braking means said emergency braking signal when said maximum permissible lateral departure exceeds said actual lateral departure by less than a predetermined value.

19. The improvement set forth in claim 18, wherein said constant-defining circuit defines a constant depending on maximum speed of travel of said vehicle.

20. The improvement set forth in claim 18, wherein said sensor and said circuit arrangement are incorporated in a module which is detachably mounted on the vehicle.

21. The improvement set forth in claim 18, wherein said vehicle comprises a steering mechanism for steering said driven wheel in dependence on said angular misalignment signal and said actual lateral departure signal.

22. In a module for use in a vehicle travelling along a guideline which extends at the center of a path defined by obstacles on at least one side, which vehicle comprises a steerable driven wheel, means defining a maximum steering angle for said driven wheel, travel drive means for driving said driven wheel, braking means arranged to effect an emergency braking of said vehicle within a predetermined maximum emergency stopping distance in response to the delivery of an emergency braking signal to said braking means, which module comprises a sensor which has first and second sensor output terminals and is operable to deliver at said first sensor output terminal an angular misalignment signal representing the angle between the longitudinal axis of the vehicle and said guideline and to deliver at said second sensor output terminal an actual departure signal representing the actual lateral departure of a predetermined point of the longitudinal center line of the vehicle from said guideline and a circuit arrangement for initiating an emergency braking operation of said braking means in dependence on said angular misalignment signal and said actual angular departure signal,

the improvement residing in that said circuit arrangement comprises

a processor having a first input terminal adapted to be connected to said first sensor output terminal, a second input terminal adapted to be connected to said second sensor output terminal, a third input terminal, and a constant-defining circuit defining a constant which depends on the contour of said vehicle in plan view and on said maximum emergency stopping distance,

a maximum departure signal generator connected to said third input terminal and operable to deliver to said third input terminal a maximum departure signal representing a maximum lateral departure of a predetermined point on said longitudinal center line from said guideline in dependence on said maximum steering angle and the width of said path of travel,

said processor being operable to compute a maximum permissible lateral departure of said predetermined point of said longitudinal center line from said guideline in dependence on said actual lateral departure signal, said maximum departure signal, said angular misalignment signal, and said constant, and to deliver to said braking means said emergency braking signal when said maximum permissible lateral departure exceeds said actual lateral departure by less than a predetermined value.