DE2063809A1 - Measuring head for an inductive vehicle control system - Google Patents

Description

Patent description measuring head for an inductive vehicle control system Die Invention relates to a measuring head, including the associated electronic Circuit for an inductive vehicle control system.

For automatic vehicle guidance it is necessary to select the respective Position of the vehicle (actual value), based on the specified path (target value), to know in order to create a control signal which, according to the corresponding electrical or hydraulic amplification a change in the steered wheels of the vehicle causes. Such a predetermined path or guideline for automatic driverless Driving vehicles can be through an alternating current flow-through conductor, for example in the form of a wire. With the help of coils this becomes the guide wire surrounding concentric alternating electromagnetic field measured, its strength is a measure of the distance between the coils, and thus the vehicle, from the guide wire, d. H. the position of the vehicle in relation to the guide wire. Procedure of this kind, which is called inductive F ahrzeugleitsystem or also called "Leitkabelystem'l" for short, are since Known for some time (British Patent Specification 549674 (1941) and British Patent Specification 963349 (1961)) and are e.g. B.

used in industrial trucks.

However, all previously known methods of this type have decisive ones Disadvantages caused by the type of coil arrangement - construction of the measuring head and the Type of conversion of the signals received in the measuring head - circuit arrangement - justified are. The disadvantages are so serious that so far only excellent positions perpendicular to the guide wire, for example in the case of a guide cable laid in the ground above, could be used as a given path. The disadvantages of the guide wire system with their previous form of the measuring head and the circuit arrangement can summarize as follows: that of a coil received signal, if this is on a straight line (11) at right angles at a distance (h) to an alternating current Head (8) is guided is not only dependent on the lateral distance x from Guide wire, but also from all other movements of the vehicle and thus of the Measuring head. In addition, it is strongly non-linear.

Especially height fluctuations of the vehicle (d h) and thus of the measuring head have a very strong effect on the measurement signal, so that the measurement signal cannot be inferred is whether the vehicle is driving over a bump in the ground or off the specified path has deviated.

Rolling, yawing and pitching movements have the same effect as changes in altitude of the vehicle and thus of the measuring head on the measurement signal formed.

The invention is based on the object of creating a measurement signal that when the guide wire is laid, preferably in a horizontal surface, for example the surface of the earth, allows the distance of the plumb point of the measuring system in this area and thus the distance between the vehicle and the guide wire Way to link linearly in the simplest case and that in addition to the above mentioned Avoids errors completely or significantly reduces their influence on the measurement signal.

The object is achieved in that two at right angles crossed coils, the planes of which are aligned parallel to the guide wire, thereby characterized in that at the outputs (4, 5) of the two coils (1, 2) one of the Electronic squaring and adding of these received electrical signals Circuit (7) and connected to this a second electronic circuit (9) is the induced signal of that coil (1) whose level is to be determined Distance from the guide wire (8) is parallel, through which in the first circuit (7) formed electrical quantity divided. Electronic circuits with the above listed properties are easy to create or as a finished "Analog modules" are available for sale, so that they will not be discussed in detail needs.

An alignment of the coil plane parallel to the guide wire can thereby be achieved that the same preferably in a horizontal plane, for example the earth's surface (10) is laid and the coils crossed at right angles, for example by a cardanic suspension (not shown here) using the gravitational field the earth are attached to the vehicle so that the plane of a coil (1) always parallel and that of the other coil (2) always perpendicular to the earth's surface and also is held in the longitudinal direction of the vehicle.

With the system described it is achieved that the output of the electronic circuit (9) pending electrical signal proportional to the distance of the plumb point of the measuring head from the guide wire is independent of height fluctuations (o h) or by nodding resp.

Rolling movements of the vehicle. Yaw movements still have one Influence; however, as a first approximation it is permissible to assume that it is neglected as the vehicle's longitudinal axis is practically always in the stable driving condition aligned parallel to the guide wire.

As an extension of the inventive concept, the fact that the first the electrical signals of the two coils (1, 2) squaring and adding electronic Circuit (7) is supplemented to the effect that the electrical output variable Square of the in a third to the two first-mentioned coils (1, 2) perpendicular arranged coil (3) induced electrical signal is added, can be achieved, that the influence of yaw movements on the measurement result is completely eliminated, i.e. the right-angled distance of the plumb point of the measuring system for Guide wire can be completely independent of the movement of the vehicle and thus of the measuring head be measured.

The vehicle control system described is a continuation of the inventive concept expanded in that the guide cable (8) part of a wire loop with a preferably feedback running parallel to it and possibly influencing the measured variable (12), the cross connections (13) of both conductors (8, 12) being ferromagnetic are shielded.

The function of the measuring head for a vehicle control system is shown on hand of Figures 1 to 4 described in more detail. They show: FIG. 1 the perspective arrangement of the vehicle control system consisting of the coils (t, 2, 3) of the measuring head and the Guide wire (8).

Figure 2 The representation of the vehicle control system in the Z-X plane.

Figure 3 The circuit arrangement for processing the induced in the measuring head electrical signals.

Figure 4 The guide cable (8, 12) extended to a wire loop.

The following are shown in detail: The coils (1, 2), their coil plane is arranged parallel to the guide wire (8) (in Figs. 1 and 2) and the coil (3), their plane perpendicular to the first two and thus also perpendicular to the guide wire stands. In Fig. 2 is through the earth's surface (10), for example, a horizontal Laying of the guide cable (8) indicated, while the horizontal line (11) Guide of the measuring head is shown at a distance h. In Figure 3 are the three coils (1, 2, 3) symbolically in their position to the guide wire (8) and the electronic processing their signals in the electronic circuit (7) consisting of two or three squaring (Q) and an adding (+) element and the circuit (9) consisting of one dividing element (D) shown. All of these electronic circuits are as "Analog modules" available on the market. Fig. 4 shows the extension of the Guide cable (8) to a wire loop (8, 12) running through an alternator (14) of conventional design is fed, and their transverse ends by ferromagnetic tubes are shielded.

Claims (3)

Claims 1,) Measuring head for an inductive vehicle control system consisting of two at right angles crossed coils, the planes of which are aligned parallel to the guide wire (8) are, characterized in that the outputs (4, 5) of the two coils (1, 2) one that squares and adds the electrical signals received by them electronic circuit (7) and to this a second electronic circuit (9) is connected, which is the induced voltage of that coil (1) whose level to the to be determined distance from the guide wire (8) is parallel, through the in the first Circuit (7) divided electrical quantity formed. 2. measuring head for an inductive vehicle control system according to claim 1, characterized in that the first, the electrical signals of the two coils (1, 2) squaring and adding electronic circuit (7) added accordingly is that its electrical output is the square of in a third, to the two first-mentioned coils (1, 2) vertically arranged coil C3) induced electrical signal is added. 3. Vehicle control system according to claim 1 or 2, characterized in that that the guide cable (8) part of a wire loop with a preferably parallel to it running and possibly influencing the measured variable return (12) is, wherein the cross connections (13) of the two conductors (8, 12) are ferromagnetically shielded are.