Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits
  • B62D6/02—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits responsive only to vehicle speed

Definitions

• the present invention relates to an arrangement in an electrical control system for controlling a motor vehicle with a control element, especially a steering wheel, and elements for translating a control movement of the said control element, especially the steering wheel lock, into a corresponding turning of the steered wheels of the vehicle, the control system comprising: a sensor that is operatively connected to the control element and is designed to generate an electrical signal corresponding to the control movement, means designed to continuously register the speed of the vehicle and to form an electrical signal corresponding thereto, means of signal processing designed, on the basis of the control movement signal and the speed signal, to produce a control signal for the transmission element, so that for a certain control movement the corresponding turning of the wheels is less at a high vehicle speed than it is a low vehicle speed.
• the present invention also relates to a method of achieving control of the vehicle by way of a control system for a motor vehicle comprising a steering wheel and elements for translating a turning of the steering wheel into a corresponding lock of the steered wheels of the vehicle.
• EP 0 596 167 describes a system intended for a vehicle for materials handling, such as a forklift truck, for example.
• the system is designed to vary the control ratio as a function of the speed of the vehicle in such a way that the steering wheel lock can be increased at low speeds, in order thereby to obtain an increased control sensitivity, with the intention of making the truck easy to manoeuvre and easy to park at these low speeds.
• An object of the present invention is to provide an improved steering wheel with associated control system for controlling a vehicle intended to be driven on public roads, for example in the form of a passenger car.
• a further object of the present invention is to provide a steering wheel on which fitted controls, for example elements for controlling the direction indicators, are easily accessible and simple to operate even at maximum steering wheel lock.
• Preferred embodiments have any or some of the characteristics specified in the subordinate claims 2 to 6.
• the invention also comprises a method of the type described in the introductory part, which is characterised in that the turning position of the steering wheel, which is limited to a maximum turning position in both directions, is continuously converted into an electrical signal; the speed of the vehicle is continuously registered; an electrical control signal to the transmission element varying as a function of the steering wheel turning signal and the said speed is calculated so that with a certain turning of the steering wheel, the corresponding wheel lock is less at high vehicle speed than at low vehicle speed.
• the arrangement and the method according to the invention have a number of advantages compared to the prior art.
• the arrangement according to the invention is intended for vehicles designed to be driven on the public highway at speeds suited thereto.
• a very important characteristic from the safety standpoint therefore is the absence of a steering column, since in the event of a collision at moderate or high speeds this may injure the driver of the vehicle.
• the maximum steering wheel lock is ⁇ 30°, for example, and the steering wheel has elements arranged on either side, designed to control direction indicators fitted to the vehicle, even at maximum steering wheel lock the element for controlling the left-hand direction indicator will be on the left- hand side and vice-versa.
• the driver's right hand will still be located next to the right-hand element and vice- versa, since it is not necessary to change grip it order to achieve maximum steering wheel lock.
• the fact that maximum wheel turning is less at high speeds than at low speeds is also a beneficial characteristic from the point of view of safety, since it is impossible at high speeds to turn the wheels of the vehicle into a position such that cornering is unsafe. Furthermore, at low speeds the vehicle becomes very easy to manoeuvre. The invention will be explained in more detail below with the aid of examples of embodiments of the arrangement and the method according to the invention.
• Fig. 1 shows an example of a steering wheel according to the invention
• Fig.2 shows an example of the steering wheel in figure 1 fitted in a vehicle and at maximum steering wheel lock.
• Fig. 3 shows a further example of the steering wheel in figure 1 fitted in a vehicle, viewed from the left.
• Fig. 4 shows the example of the steering wheel in figure 3 fitted in a vehicle and view from the left.
• Fig. 5 shows an example of a system according to the invention for controlling the turning of the wheels as a function of the steering wheel lock and the speed at which the vehicle is being driven.
• Fig. 6 shows a graph, which illustrates the wheel turning in relation to the speed of the vehicle for a certain steering wheel lock.
• reference number 1 denotes a control element for controlling a motor vehicle, especially one intended to be driven on the public highway; the motor vehicle is a passenger car or a lorry, for example.
• the control element is, in particular, a steering wheel, but may also be a so-called joystick, for example.
• the steering wheel 1 in this embodiment has operating control elements in the form of buttons 2a, 2b, 2c, 2d, 2e, 2f connected to its hub, for example for a stereo system in the vehicle and designed for the operation thereof.
• the steering wheel furthermore has elements 3 a, 3b on each side, designed when either of these is operated to switch associated direction indicators fitted to the vehicle on or off, the element 3a on the right being intended to operate the right-hand direction indicators of the vehicle and the element 3b on the left being intended to operate the direction indicators on the left-hand side of the vehicle.
• Figure 2 shows an embodiment of the steering wheel 1 fitted to the dashboard 4 of the vehicle.
• the steering wheel 1 in this figure is turned clockwise as far as possible to a stop.
• the steering wheel can also be turned anticlockwise to a corresponding stop.
• the stops are located on either side of the central position in figure 1 with equal angles of rotation in relation to the central position.
• the maximum angle of rotation in both directions defined by the stops may be such that when the steering wheel is turned to either of these, the element 3a is still situated on the right-hand part of the steering wheel and the element 3b is still situated on the left-hand part of the steering wheel.
• the stops may be situated at an angle of rotation of ⁇ 30°.
• the maximum angle of rotation is such that in order to attain the maximum steering wheel lock there is no need to change grip on the steering wheel, in this embodiment the maximum angle of rotation may be at up to ⁇ 90°.
• the maximum angles of rotation are situated somewhere in the interval between ⁇ 30° and ⁇ 90°, but ought preferably to be selected in the interval between ⁇ 30° and ⁇ 45°.
• Figures 3 and 4 show another embodiment of the steering wheel 1 fitted to the dashboard 4 of the vehicle.
• satellites are fitted adjacent to the steering wheel 1, operating control elements 2g, 2h, 2i, 2j, 2k, 21, 2m, 2n being fitted to the said satellites.
• all operating control elements 2a-2n, 3a, 3b are accessible and operatable without the driver of the vehicle having to let go of the steering wheel.
• the operating control elements 2g-2n may be fitted to the steering wheel unit so that they follow when this is turned; this is particularly advantageous in the case of large maximum steering wheel locks in excess of ⁇ 45°, for example.
• the operating control elements may also be arranged fixed by the steering wheel unit, that is to say not capable of rotating with the steering wheel.
• the operating control elements 2a-2n may be used for all types of peripheral equipment, such as windscreen wipers, cruise control, trip computers and telephone, for example, which for safety reasons should be capable of operation without letting go of the steering wheel.
• the reference number 6 denotes a sensor, which is operatively connected to the steering wheel 1 and is designed to generate an electrical signal corresponding to the rotation of the steering wheel.
• the signal is such that it has a voltage level of 0V at the maximum anticlockwise rotation of the steering wheel and a voltage level of 5 V at the maximum clockwise rotation of the steering wheel, and progressively increasing voltage from 0 to 5V as the wheel is turned progressively from the position of maximum anticlockwise rotation to the position of maximum clockwise rotation.
• the electrical signal corresponding to the steering wheel rotation is fed from the sensor 6 to a signal processing element 5 by way of a line 8.
• the feed voltage to the signal processing element 5 is 12 volts, for example.
• control system 7 which are designed, according to any conventional method, to continuously register the speed of the vehicle, and to deliver an electrical signal corresponding to the speed of the vehicle to the signal processing unit 5 by way of a line 9.
• the signal processing unit 5 is designed, on the basis of the steering wheel rotation signal via the line 8 and the speed signal via the line 9, to produce a control signal, which is fed by way of a line 11 to the remaining part of the control system 10.
• the said remaining part of the control system is designed to control how far the wheels of the vehicle turn in proportion to the control signal over the line 1 1.
• the control system may be designed in a number of different ways; the embodiment shown in figure 3 will be described in more detail later.
• the speed-dependent signal received by the signal processing unit 5 over the line 9 is a frequency signal, the frequency of which has a linear speed dependence so that the signal has a high frequency at high speeds and a low frequency at low speeds.
• the signal is allowed to pass through a conversion element 5b, in which the frequency signal is converted to a voltage signal similar to the steering wheel lock-dependent signal described above.
• the speed- dependent signal is then fed, together with the steering wheel lock-dependent signal, over the line 8 to a calculating element 5a, in order to calculate the control signal to the remaining part of the system 10 from the signals fed in.
• the calculating element 5a is designed to limit the steering wheel lock-dependent signal if the speed-dependent signal exceeds a predetermined value vi. For speeds lower than the speed v ⁇ the steering wheel lock signal is allowed to pass through the calculating element 5a to the line 11 , without the steering wheel lock signal being limited.
• the predetermined system is such that the control signal for an essential part of a speed interval v ⁇ -v 2 is inversely proportional to the speed signal, that is to say for a certain steering wheel lock the control signal is reduced in proportion to the increase in the speed signal.
• the speed dependence of the control signal is such that gentle transitions occur between the speed dependence at speeds lower than vj and the inversely proportional speed dependence in the essential middle part of the interval Vj-v 2 , and between the said middle part and the speed-dependent part at speeds in excess of v 2 .
• the choice of suitable speed interval should be made with regard to factors such as the size of the vehicle, turning circle etc. How the signal processing element 5b is realised in practice is not essential for the invention; it may form part of the hardware or of the software.
• the wheel turn can be achieved by means of rack and pinion steering.
• the control signal via the line 1 1 is applied to a motor 12 designed to drive a pinion, fitted in the vehicle and engaging with a toothed rack in accordance with the control signal, so that the toothed rack is shifted to a position corresponding to the control signal over the line 1 1. In this way the desired turning of the wheel 13 of the vehicle is achieved.
• the present invention can be implemented in electric or hybrid vehicles, and also in petrol or diesel-powered vehicles, and both for vehicles with electrically controlled hydraulic power steering and for vehicles with electric power steering.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Steering Control In Accordance With Driving Conditions (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20413790

Family Applications (1)

Country Status (2)

Cited By (4)

Citations (7)

• 1998
  • 1998-12-21 SE SE9804467A patent/SE9804467L/sv not_active Application Discontinuation
• 1999
  • 1999-12-14 WO PCT/SE1999/002334 patent/WO2000037300A1/en not_active Application Discontinuation

Patent Citations (7)

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