Procedure and System for Driving a Vehicle

This invention relates to a procedure and a system for driving a vehicle required to travel repeatedly over the same path, possibly at various speeds. The invention relates to vehicles whose path is determined by mechanical guides, e.g., rails, and by electric or radio guides or markers such as buried or immersed electric cables extending along the path, beacons etc.

Of course, when the driver of a motor vehicle travels over the same section of road repeatedly, he learns the road and gradually records unusual features thereof which may cause him to alter his path, speed and so on. He acquires road knowledge which makes him drive more rationally and smoothly and economically and/or faster. Driving improves in proportion as road knowledge is better. Repeated driving over the same route becomes a virtually mechanical operation. Also, driving is better in proportion as the driver sees further ahead -- i.e., becomes aware sooner of disturbing incidences on his route.

On the other hand, for instance, a train which keeps on making the same journey is driven on each journey as if it was making the trip for the first time; consequently, trains, although less dependable and more reliable than motor vehicles, are considerably inferior to the latter in their performances.

It is an object of this invention to obviate this disadvantage.

According to the invention, therefore, in a procedure for driving a vehicle required to travel repeatedly over the same path, in which procedure at least some elements of the vehicle are operated in accordance with pre-recorded information, the information relates to the operations to be performed on or by such elements in relation to the position of the vehicle on his path, and the elements are operated on the basis of such information in the light of the vehicle's instantaneous position with a correction for instantaneous vehicle speed and the response time of the elements. The vehicle elements can therefore start to be operated in advance to ensure optimum operation at the right time when the vehicle is at the corresponding place. Clearly, therefore, the pre-recorded information contents ensure that the vehicle is driven on the basis of acquired habits, and the use made of such information enables the vehicle to be driven on a basis of anticipation.

The recorded information can result from a recording made either in a first journey in normal driving conditions or in a laboratory, having due regard to the listed items of the trip or path.

Of course, the operated elements can be of various kinds, such as rams or motors or valves or the like, which can control axle orientation, vehicle body tilt, suspension compression and so on. The driving and/or comfort of the vehicle can therefore be optimized by communicating to such elements the conditions and/or the optimum position to be taken up throughout the journey.

Advantageously, the amplitude and speed of operation of some elements can depend upon instantaneous vehicle speed; for instance, vehicle body tilt on a curve to offset centrifugal force is preferably calculated in dependence upon vehicle speed.

In the procedure according to the invention, therefore, the vehicle elements "know" what they have to do throughout the journey. Advantageously, they are also given an indication, in the form of a reference value, of the result they must reach throughout the journey. The reference value can be fixed; however, according to another feature of the procedure according to the invention, the pre-recorded information relates not only to the operations to be performed on the elements but also to the results to be achieved thereby in relation to the position of the vehicle on its path. Consequently, not only does the vehicle "know" what is has to do in dependence upon what is going to happen to it but also its control cannot drift. Driving can therefore become completely automatic.

A system for using the procedure according to the invention can comprise: a store containing information about the actions to be performed on at least one element related to the position of the vehicle on its route; first means for supplying the instantaneous position of the vehicle; second means for supplying the instantaneous position of the vehicle, third means for supplying particulars of the response time of the element to be controlled: a computer receiving the output signals of the three means and outputting an anticipated vehicle position; means for reading the store at the anticipated vehicle position; and means for regulating such element and receiving the output from the store corresponding to such anticipated position.

The system can comprise a second computer which receives the output signal of the second means and which provides the regulator with a reference signal for operating the element in dependence upon the nature of the action.

Between the regulator and the element operated thereby there is a summer, one of whose inputs receives the regulator output signal and the other of whose inputs receives the output signal of a second regulator disposed in a control loop for the operation of the element controlled by the first regulator. Preferably, the reference signal supplied to the loop comes from a second store containing pre-recorded information about the results to be provided by the regulated element in relation to the position of the vehicle on the path.

The accompanying drawings will make clearly apparent how the invention can be carried into effect. In the drawings:

FIGS. 1 to 3 are block schematic diagrams of three embodiments of the system according to the invention.

Like references denote like elements throughout the drawings.

The system according to the invention as shown diagrammatically in FIG. 1 is fitted to a vehicle (not shown) which repeatedly makes the same journey. The system comprises a computer 1 simultaneously receiving signals from a position sensor 2, a speed sensor 3 and a response time indicator 4. Sensor 2 indicates the instantaneous position of the vehicle, e.g. its abscissa x on the vehicle path. Sensor 3 delivers the instantaneous vehicle speed V. It would be possible for the speed V to be calculated from x by means of a differentiator 5. Indicator 4 delivers a time T corresponding, with allowance for adjustments, to the response time of the control channel of a final control element 6.

Computer 1 computes an abscissa x' such that:

i.e., x' leads on x by the amount VT.

Computer 1 transmits its signal x' to a store 7 containing a table of the actions to be performed by element 6 in dependence upon the abscissae x; store 7 provides a regulator 8 with the action corresponding to the abscissa x', whereafter regulator 8 operates the final control element 6.

Consequently, while the vehicle is still at the abscissa x, the final control element 6 receives the instruction which it will have to implement when the vehicle is at position x'. Actuation of the final control element 6 is therefore anticipated by the distance VT or, if the speed V remains constant between the positions x and x', by the time T.

If the final control element 6 is required to be operated in a manner dependent upon the instantaneous vehicle speed V, the system according to the invention also comprises (see FIG. 2) a computer 9 which receives the signal V from sensor 3 and which supplies the regulator 8 e.g. with a signal V.sup.k to operate the final control element 6 in dependence upon a power of V. The factor k can have values which depend upon the kind of operation provided by the elements 6; for instance, if the same control vehicle body inclination to allow for track superelevation and centrifugal force on curves, the factor K can be 2.

The systems shown in FIGS. 1 and 2 are appropriate for operations performed against the force of resilient means or as far as a fixed abutment etc. The amplitude of the operations is determined by an element external to the systems.

FIG. 3 shows a system according to the invention wherein the amplitude of the operation of the elements 6 can be controlled. To this end, the system, which comprises the elements 1-9 hereinbefore described, further comprises a summer 10 having one input connected to the output of regulator 8 and having its output connected to the input of the final control element 6. The same also forms part of a control loop comprising a comparator 11 and a second regulator 12. Comparator 11 receives the output signal of element 6 and a reference signal provided either by a fixed reference system 13 or, preferably, a prerecorded-reference system 14. The output signal of comparator 11 is applied to the second regulator 12 whose output is connected to the other input of summer 10.

The prerecorded-reference system 14 comprises a store in which a characteristic value of the result of the operation of element 6 corresponds to each value of x. Such information plus the information of store 7 can be derived from a registration made in a previous trip over the same path. Of course the stores 7, 14 can be embodied by the same store or by parts of the same store. Store 14 is read in dependence upon the indication x given by the position sensor 2 and delivers at its output the result of the corresponding action.