GB2181502A - Vehicle traction control device - Google Patents
Vehicle traction control device Download PDFInfo
- Publication number
- GB2181502A GB2181502A GB08524946A GB8524946A GB2181502A GB 2181502 A GB2181502 A GB 2181502A GB 08524946 A GB08524946 A GB 08524946A GB 8524946 A GB8524946 A GB 8524946A GB 2181502 A GB2181502 A GB 2181502A
- Authority
- GB
- United Kingdom
- Prior art keywords
- control device
- rotational speed
- traction control
- wheel
- control system
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
- B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
- B60T8/3205—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration acceleration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
- B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
- B60T8/321—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration deceleration
- B60T8/322—Systems specially adapted for vehicles driven by more than one axle, e.g. Four Wheel-Drive vehicles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
- B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
- B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
- B60T8/48—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition connecting the brake actuator to an alternative or additional source of fluid pressure, e.g. traction control systems
- B60T8/4809—Traction control, stability control, using both the wheel brakes and other automatic braking systems
Landscapes
- Engineering & Computer Science (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Regulating Braking Force (AREA)
Abstract
A traction control device which prevents wheel spin (or track spin) and which may be easily fitted to a vehicle after manufacture is intended for use with a vehicle having at least one pair of wheels (or endless tracks) driven through a differential gear. It comprises independent braking means associated with each or all of the differential driven wheels, rotational speed sensing means associated with each or all of the differential driven wheels, and a central control system adapted to receive rotational speed information from the speed sensing means and optionally the steering mechanism. The central control system supplies brake actuating signals to the braking means whenever the rotational speed of one wheel in a pair exceeds that of the other by a predetermined amount, the brake actuating signal is supplied to the wheel having the higher rotational speed. Where the vehicle has more than one pair of differential driven wheels, e.g. four driven wheels, the control system uses the slowest wheel as its datum point and matches the other wheel speeds to it by means of their individual braking means. The central control system is preferably electrical and may use a microprocessor to compute the necessary brake actuating signals to each wheel. <IMAGE>
Description
SPECIFICATION
Vehicle traction control device
This invention relates to a method of controlling wheel torque in vehicles using differential drive gears.
The driving wheels of motor vehicles which have to be steered normally use a differential gear to transmit the driving power from the engine to the wheels. The purpose of the differential gear is to separate the two drive axles so that power can be transferred equally to each drive wheel. As the vehicle turns the outside wheel must complete more revolutions than the inside wheel but, using a differential gear, the torque input to each wheel remains equal.
The differential gear, while essential on good driving surfaces, is a positive disadvantage when the surface provides poor adhesion with the driving wheel, for example on wet, muddy, icy or loose textured surfaces. Frequently one wheel will lose adhesion altogether and spin freely while the other wheel receives no driving torque and remains stationary even though there is good adhesion.
Under these conditions the vehicle will not move. Many vehicles for use on poor surfaces have two sets of wheels driven by differential gears. Frequently even these vehicles are rendered immobile when one wheel of each set looses adhesion.
In the case of agricultural tractors which tra vel across muddy fields the problem is overcome by means of a differential lock. This device turns the differential gear into a direct drive gear; a satisfactory arrangement only if the the vehicle is travelling in straight lines, for instance when drawing a plough. The lock must always be disconnected if the vehicle is to travel on a route which requires it to turn.
An equivalent problem to wheel spin, track spin, occurs in track laying vehicles using a differential drive to the track driving sprocket wheel when such vehicles traverse wet, muddy, icy or soft ground. All references herein to driven wheels should be taken to include the sprocket drive wheels for track laying vehicles.
Attempts have been made to overcome the problems caused by wheel spin under low adhesion conditions by mechanical modifications of the differential gear such as the ZF Differential or the Thornton Powr-Lok. Installation of these devices, unless carried out during manufacture, is a lengthy and expensive as the whole of the rear drive system of the vehicle has to be replaced.
The present invention provides a traction control device which prevents wheel spin or track spin and which may be easily fitted to a vehicle after manufacture.
According to the present invention there is provided a traction control device for a vehicle having at least one pair of wheels driven through a differential gear comprising, independent braking means associated with each or all of the differential driven wheels, rotational speed sensing means associated with each or all of the differential driven wheels, and a central control system adapted to receive rotational speed information from the speed sensing means and supply brake actuating signals to the braking means, characterised in that the central control system is adapted to generate a brake actuating signal whenever the rotational speed of one wheel in a pair exceeds that of the other by a predetermined amount, the brake actuating signal being supplied to the wheel having the higher rotational speed.
When the central control system causes the faster wheel of a pair to be braked torque is applied to the other, stationary or near stationary wheel which, having better adhesion, will be able to move the vehicle.
The independent braking means associated with each differential driven wheel may be of any type. The preferred means of braking wheels involves the use of friction in the form of drum brakes or disc brakes which are well known. Control of the friction brakes may be mechanical, hydraulic, pneumatic, or electromagnetic. The braking control system may be that originally installed during manufacture or a subsequent addition or modification. The brakes may be actuated in response to mechanical, hydraulic or pneumatic signals but electrical signals are preferred. Friction brake control means of these types are well known to vehicle engineers.
The rotational speed of the wheels may be sensed by means of signal providing means associated with the wheel or its driving shaft.
Electrical signals whose frequency is related to the rotational speed of the wheel may be obtained electromagnetically, using a coil whose magnetic circuit is interrupted by metal toothed disc attached to the wheel or a Hall effect sensor which detects the passage of magnets attached to the wheel. Such signals may also be obtained optically using photosensors which detect the passage of reflective marks on the wheel. Alternatively a.c. or d.c.
tachogenerators may be used to provide a voltage proportional to the rotational speed of the wheel. Such electrical signals are easily transmitted by wires to the central control system in any convenient Location in the vehicle.
The rotational speed sensing means can be mechanically derived, for instance by a centrifugal speed sensor or an inertial sensor. Such devices are known and used in vehicle control systems.
The rotational speed of each wheel may also be transmitted mechanically to the central control system but this is liable to restrict its location. If the wheel speed is sensed optically the signals may be sent to the central control system along a light guide such as a glass or polymeric fibre.
The central control system receives the rotational speed information from each wheel in a pair and compares the two speeds. When the speed of one wheel is greater than another by a predetermined amount a brake actuating signal is generated until the speed difference is reduced to less than the limit.
The speed difference level at which braking is initiated will depend to some extent upon the type of use of the vehicle. It should not be operated by the small speed differences caused by the vehicle turning during normal driving conditions but by the larger speed differences liable to arise when muddy and icy surfaces are traversed and adhesion is lost by one of the wheels. The central control system may perform its computational functions of measuring speed difference using mechanical, hydraulic, pneumatic or electrical methods.
The electrical computation may be analogue, digital or a combination of the two. If the preferred embodiment of the invention the central control system receives rotational speed information in the form of variable frequency pulse trains and provides a two state electrical signal to the brake actuating means.
Where the vehicle has more than one pair of differential driven wheels, e.g. four driven wheels, the control system would use the slowest wheel as its datum point and match the other wheel speeds to it by means of their individual braking means. In such a situation the central control system is electrical and preferably uses a microprocessor to compute rapidly the necessary brake actuating signals to each wheel.
In a further embodiment of the invention the central control system also receives positionalinformation from the vehicle's steering mechanism. By suitable computation the control system can modify the brake actuating signals so as to compensate for the necessary speed difference between the wheels required when the vehicle is turning.
In order that the invention may be more clearly understood it will now be described with reference to the accompanying drawing in which the single figure is schematic layout of a vehicle drive and traction control system according to the invention.
A four wheel vehicle drive system consists of an engine and gear box, 1, constructed and controlled in known manner, adapted to provide power to two wheels, 3 and 4, by means of a drive shaft, 5 connected to a differential gear, 6. The differential gear 6 is coupled to the wheels 3 and 4 by means of two shafts 7 and 8. Two further undriven wheels, 9 and 10, are connected to a conventional steering mechanism, not shown.
Each of the wheels 3, 4, 9 and 10 has
independent braking means, 11, 12, 13 and 14 which are actuated in known manner through hydraulic pressure through pipes, not shown, from a cylinder, 15 operated by the driver of the vehicle through a foot pedal, 16.
The braking means 11 and 12 on the wheels 3 and 4 also have supplementary electrical actuating means. 11' and 12' associated with them.
Each of the wheels 3 and 4 carries a toothed metal disc, 23 and 24, whose teeth pass through the poles of electromagnetic pick-up coils 25 and 26. The electrical signals from the coils 25 and 26 are carried to a central control system 27 by wires 28 and 29.
The central control system 27 is a microprocessor suitably programmed to provide signals on wires, 30 or 31 which will operate the electrical brake actuating means 11, or 12, repectively.
When the vehicle is in motion, due to the driving action of the engine 1, the central control system 27 will be receiving two trains of pulses from the pick-up coils 25 and 26. The control system will continuously compare the two trains of pulses and generate a signal in one of the trains has a higher frequency than the other by a preprogrammed amount. The signal is a brake actuating signal sent to the brake actuating means 11' or 12' associated with the wheel having the high rotational speed as indicated by the higher frequency.
The brake actuating signal stops when the sensed speed difference is below the preprogrammed value. In this way torque is applied to the wheel rotating at the slower speed so that it is able to continue driving the vehicle in spite of any loss of adhesion by the other wheel.
Claims (18)
1. A traction control device for a vehicle having at least one pair of wheels driven through a differential gear comprising, independent braking means associated with each or all of the differential driven wheels, rotational speed sensing means associated with each or all of the differential driven wheels, and a central control system adapted to receive rotational speed information from the speed sensing means and supply brake actuating signals to the braking means, characterised in that the central control system is adapted to generate a brake actuating signal whenever the rotational speed of one wheel in a pair exceeds that of the other by a predetermined amount, the brake actuating signal being supplied to the wheel having the higher rotational speed.
2. A traction control device as claimed in claim 1 in which the rotational speed sensing means provides electrical signals whose frequency is related to the rotational speed of the driven wheel.
3. A traction control device as claimed in claim 2 in which the electrical signals are obtained electromagnetically.
4. A traction control device as claimed in claim 2 in which the electrical signals are obtained optically.
5. A traction control device as claimed in claim 1 in which the rotational speed sensing means provides electrical signals whose amplitude is related to the rotational speed of the driven wheel.
6. A traction control device as claimed in claim 5 in which the electrical signals are obtained from a tachogenerator.
7. A traction control device as claimed in claim 1 in which the rotational speed sensing means provides mechanically derived signals.
8. A traction control device as claimed in claim 1 in which the rotational speed sensing means provides optical signals which are carried by a fibre optical system.
9. A traction control device as claimed in claim 1 in which the central control system performs its computational functions by electrical methods.
10. A traction control device as claimed in claim 9 in which the central control system performs its computational functions by means of a digital computer.
11. A traction control device as claimed in claim 9 in which the central control system performs its computational functions by means of an analogue computer.
12. A traction control device as claimed in claim 1 in which the central control system receives rotational speed information in the form of variable frequency pulse optical or electrical pulse trains and provides a two state actuating signal to the brake actuating means to actuate the brake on the wheel of each pair with the higher rotational speed.
13. A traction control device as claimed in claim 12 in which the two state signal is an electrical signal.
14. A traction control device as claimed in claim 1 or claims 9 to 13 in which the vehicle has at least two pairs of driven wheels and central control system generates brake actuating signals using the wheel with the lowest rotational speed as its datum point.
1 5. A traction control device as claimed in claim 1 or claims 1 to 14 in which the central coritrol system receives signals from the vehicles steering mechanism and modifies the brake actuating signals so as to compensate for the necessary speed difference between the wheels when the vehicle is turning.
16. A traction control device as claimed in claim 1 in which the independent braking means are friction brakes associated with each or all of the differential driven wheels.
17. A traction control device as claimed in claim 16 in which the friction brakes are actuated in response to an electrical signal.
18. A traction control device as claimed in claim 1 and as herein described with reference to the accompanying drawing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08524946A GB2181502A (en) | 1985-10-10 | 1985-10-10 | Vehicle traction control device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08524946A GB2181502A (en) | 1985-10-10 | 1985-10-10 | Vehicle traction control device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8524946D0 GB8524946D0 (en) | 1985-11-13 |
| GB2181502A true GB2181502A (en) | 1987-04-23 |
Family
ID=10586442
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08524946A Withdrawn GB2181502A (en) | 1985-10-10 | 1985-10-10 | Vehicle traction control device |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2181502A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2289732A (en) * | 1994-05-28 | 1995-11-29 | Daimler Benz Ag | Method for increasing the drive torque of a vehicle |
| WO1997014592A1 (en) * | 1995-10-17 | 1997-04-24 | J.C. Bamford Excavators Limited | Loader type vehicle with traction control |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1544467A (en) * | 1976-08-13 | 1979-04-19 | Aspro Inc | Brake pressure modulator and system |
| GB2018922A (en) * | 1978-04-17 | 1979-10-24 | Bendix Corp | Anti-skid and ant-spin brake system |
| GB2020382A (en) * | 1978-04-28 | 1979-11-14 | Wabco Fahrzeugbremsen Gmbh | Preventing wheelspin on vehicles |
| GB2112090A (en) * | 1981-07-10 | 1983-07-13 | Daimler Benz Ag | System for controlling the propulsion of motor vehicles |
| GB2128278A (en) * | 1982-10-01 | 1984-04-26 | Kugelfischer G Schaefer & Co | Anti-wheelspin brake control for wheels driven via a differential gear |
| GB2149035A (en) * | 1983-10-26 | 1985-06-05 | Teves Gmbh Alfred | Brake system with wheel-skid and spin control for use in automotive vehicles |
| GB2150242A (en) * | 1983-11-26 | 1985-06-26 | Teves Gmbh Alfred | Anti-wheel spin and skid slip controlled brake system for automotive vehicles |
| GB2154293A (en) * | 1984-02-06 | 1985-09-04 | Bosch Gmbh Robert | Improvements in or relating to vehicle brake systems having means for the reduction of drive slip |
-
1985
- 1985-10-10 GB GB08524946A patent/GB2181502A/en not_active Withdrawn
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1544467A (en) * | 1976-08-13 | 1979-04-19 | Aspro Inc | Brake pressure modulator and system |
| GB2018922A (en) * | 1978-04-17 | 1979-10-24 | Bendix Corp | Anti-skid and ant-spin brake system |
| GB2020382A (en) * | 1978-04-28 | 1979-11-14 | Wabco Fahrzeugbremsen Gmbh | Preventing wheelspin on vehicles |
| GB2112090A (en) * | 1981-07-10 | 1983-07-13 | Daimler Benz Ag | System for controlling the propulsion of motor vehicles |
| GB2128278A (en) * | 1982-10-01 | 1984-04-26 | Kugelfischer G Schaefer & Co | Anti-wheelspin brake control for wheels driven via a differential gear |
| GB2149035A (en) * | 1983-10-26 | 1985-06-05 | Teves Gmbh Alfred | Brake system with wheel-skid and spin control for use in automotive vehicles |
| GB2150242A (en) * | 1983-11-26 | 1985-06-26 | Teves Gmbh Alfred | Anti-wheel spin and skid slip controlled brake system for automotive vehicles |
| GB2154293A (en) * | 1984-02-06 | 1985-09-04 | Bosch Gmbh Robert | Improvements in or relating to vehicle brake systems having means for the reduction of drive slip |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2289732A (en) * | 1994-05-28 | 1995-11-29 | Daimler Benz Ag | Method for increasing the drive torque of a vehicle |
| US5597215A (en) * | 1994-05-28 | 1997-01-28 | Mercedes-Benz Ag | Method for increasing drive torque with controlled brake engagement |
| GB2289732B (en) * | 1994-05-28 | 1998-07-29 | Daimler Benz Ag | Method for increasing effective drive torque |
| WO1997014592A1 (en) * | 1995-10-17 | 1997-04-24 | J.C. Bamford Excavators Limited | Loader type vehicle with traction control |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8524946D0 (en) | 1985-11-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101516652B (en) | Controller for vehicle | |
| US5419624A (en) | Arrangement for detecting a critical driving torque in a motor vehicle | |
| US4763262A (en) | Propulsion control using longitudinal acceleration, steering angle, and speed to select slip threshold | |
| RU2701289C2 (en) | Agricultural working machine and method of assistance to steering control | |
| JP3617680B2 (en) | 4-wheel drive traction control system | |
| CN101516654A (en) | Controller for vehicle | |
| EP0458800A1 (en) | Circuit arrangement for a brake system with antilock and/or traction slip control. | |
| JPH0358937B2 (en) | ||
| EP0435833B1 (en) | A method and a system for controlling traction in motor vehicles with mechanical gearboxes | |
| JPH02175333A (en) | Method and apparatus for controlling isolation differential gear | |
| SE8305174D0 (en) | DEVICE FOR EXPLOITATION OF ANY EVENT VALUE BETWEEN TWO THROUGH A DIFFERENTIAL GEAR DRIVING WHEELS WITH A VEHICLE | |
| CN109131640A (en) | Omnidirectional's steering wheel | |
| JPH0133365B2 (en) | ||
| US6349255B1 (en) | Method and device for producing a signal representing a motor vehicle running conditions | |
| CA2303593A1 (en) | Tracked vehicle steering system with steering pump monitoring | |
| JPS5970235A (en) | Controller for driving wheel of automobile | |
| GB2181502A (en) | Vehicle traction control device | |
| US5366282A (en) | Drive slip regulating system | |
| JP3410112B2 (en) | Simulated vehicle speed calculation method for four-wheel drive vehicles | |
| EP0818372A3 (en) | System for controlling the traction and the braking of a railway vehicle | |
| JPS63195033A (en) | Drive force controller for vehicle with electric motor | |
| JPS61291261A (en) | Antiskid device for vehicle | |
| KR101347741B1 (en) | Maned and unmaned steering motion control apparatus for electric car with in-wheel motor | |
| JPH0536251B2 (en) | ||
| SU593944A1 (en) | Automatic control system of the differential gear of driving axle of wheeled vehicle |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |