DE2344291C2 - Safety device for an arrangement for the tracking of track-free vehicles - Google Patents

Description

5. Safety device according to one of the preceding claims, characterized in that The first threshold value stage (19) and the safety switching stages (23, 24, 28) wipe a memory stage (20) is switched to store an error signal from the threshold value stage (19).

6. Safety device according to claim 5, characterized in that a deletion device (21) connected to the memory stage (20) for preferably manual deletion of the memory contents IGt.

7. Safety device according to one of the preceding claims, characterized in that the one provided for triggering the safety switching stages (23, 24, 28) for the further threshold value stages (29, 30, 31) associated threshold value stage (29) is connected to an input of the memory stage (20) fet.

8. Safety device according to one of the preceding claims, characterized in that the first safety switching stages (23, 24) are provided for triggering the vehicle brakes.

9. Safety device according to claim 8, characterized in that the first safety switching stages (23, 24) the fuel supply to the internal combustion engine of the vehicle can be throttled.

10. Safety device according to claim 8, characterized in that a further safety switching stage (28) for separating a steering actuator from the steering part of the vehicle

is provided.

11. Safety device according to claim 10, characterized in that the control of the further safety switching stage (28) via a logical OR switching stage (27) takes place, its additional inputs with other to be checked Vehicle facilities are connected.

12. Safety device according to one of the preceding Claims, characterized in that any number of functional units to be checked the safety device and the vehicle with inputs of a logical NAN D switching stage (25) are connected, the output of which is connected to an input of the memory stage (20), so that when Occurrence of an error signal in one of the connected functional units of the memory stage (20) an error signal can be supplied.

13. Safety device according to claim 12, characterized in that by a Feiilersignal the logic NAND switching stage (25) a warning device (26) can be triggered.

14. Safety device according to one of the preceding claims, characterized in that any switching stages of the safety device to increase safety at least twice are executed.

The invention relates to a safety device according to the preamble of the main claim.

To prevent damage if a track-free vehicle due to any fault from the guide wire deviates, a safety device is required that guarantees safe emergency braking in this case.

A safety device is known in which, in addition to the sensors for lane guidance, two further sensors are attached to the front of an automatically guided vehicle . If a vehicle deviates too far from the target course. Depending on the deviation, one of these coils stands vertically above the guide cable for a short time and thereby triggers an impulse. which initiates emergency braking. However, this arrangement has the disadvantage that the limit value for the lateral deviation is defined by the coil spacing and cannot be varied as a function of the speed. In addition, special function monitoring is required for these sensors.

From DE-OS 16 13 991 is also an electrical Control device for a guide wire-guided vehicle is known in which the drive motor when the in A voltage induced by a reference coil can be switched off below a certain value. In doing so, however no distinction was made as to whether the voltage dropped to too high a lane deviation of the vehicle or to an impermissible drop in the guide wire current is due. Furthermore, it is not taken into account that at different driving speeds z. B. Different permissible lane deviations in curves can result.

The invention is therefore based on the task of using the sensors for driving the vehicle at the same time Monitoring of the lateral deviation taking into account the depending on the driving speed changing permissible deviation, with none for the safety logic additional sensors can be used.

This object is achieved by the measures specified in the characterizing part of the main claim.

To increase safety, it is advisable to also monitor the signal level in the guide wire can. For this purpose, in a further embodiment of the invention, a from the Wechselspanr.iingsatuplimde el · -; · Guide wire voltage-dependent signal detected by the sensors of at least one further threshold value stage can be supplied, through which at least one safety switching stage when the threshold value is undershot releasable H

The advantages achieved by the invention are in particular that the permissible lane deviation can be determined depending on the driving speed, so that the special conditions, especially when cornering. Another advantage is that the safety logic does not requires additional sensors and that the security device any further information about Signal level in the guide wire, lane deviation, supply voltages. Braking pressures. Driving speed. Disturbances in the steering logic. Disruptions in the Brake logic etc. can be entered. Üa the sensors for driving the vehicle at the same time as driving tool monitoring are used, the signal only needs to be processed once.

An embodiment of the invention is shown in the drawing and will be described in more detail below described. A block diagram of a safety device is shown as an exemplary embodiment.

Two sensors 10, 11 scan the magnetic field of the guide wire, not shown in the block diagram, and feed the received signals to a signal processing stage 12. The signal processing stage 12 has two outputs connected to terminals 13, 14. There is a signal at terminal 13. that in Ratio to the deviation of the vehicle from the guide wire varies. This signal has depending on the direction of deviation an opposite sign. The implementation of such a signal is the simplest Case achieved in that the sensors 10, 11, preferably designed as magnetic coils, on the left and are arranged to the right of the center of the vehicle and that of the received signals in the signal processing stage a difference signal is formed. At the other output of the signal processing stage 12. d. H. at terminal 14 there is one for the alternating voltage amplitude DC voltage proportional to the guide wire voltage. This is done in the simplest case realized that the signals of the sensors 10,11 in one, in the signal conditioning stage 12 contained summing stage can be added. A level control can be provided that controls the value of this direct voltage keeps constant and a change is only allowed when the control limits are reached. There are several vehicles at the same time automatically led to courses that deviate from one another, it may be necessary to use different Use frequencies for tracking. In the signal processing unit 12 are then possibly Built-in filter stages.

Another way to record the to the Signals applied to terminals 13, 14 by sensors 10, II are arranged in a crosswise manner of the two coils in the middle of the vehicle. Such an arrangement is less sensitive to interference.

The signals applied to terminals 13, 14 are not closer to either one in the block diagram shown steering controller and a steering actuator of the vehicle, which is indicated by arrows is indicated, as well as the safety device now described below.

Since the amount of the deviation is important for the evaluation in the safety device, the K'i .-; ne Π Cfher a known amount formation step 15 connected to a summing stage 16. With automatically guided vehicles for higher speeds does it make sense for security reasons,

ίο the limit value for the maximum permissible lateral deviation to track depending on the speed. For this purpose, a terminal 17 generated in a known manner, on the speed of the vehicle dependent signal via a control amplifier 18 also the

' ί summing stage 16 supplied. A signal thus appears at the output of the summing stage 16 which is proportional to the transverse deviation | y | and to the speed ν of the vehicle. The following relationship was used to determine the maximum permissible transverse deviation

- ° laid:

IV I + k - v- const.

k is a factor for optimizing the switch-off characteristic and can be set in the control amplifier 18. - 'The sum voltage at the output of the summing stage 16 is fed to a threshold value stage 19, at the output of which a 1-signal appears when a certain threshold value is exceeded by the sum voltage. This 1 signal triggers the safety device. A! Signal and an O signal are terms used in digital technology, an O signal denoting a potential which, sewing, corresponds to the ground potential and a 1 Signa! denotes a potential which approximately corresponds to the supply voltage.

A 1-error signal at the output of the threshold value stage 19 is fed to a memory stage 20, where it is stored until it is deleted again by a deletion device 21. A simple realization Stage 20 and 21 is a thyristor, which is made conductive by an error signal, and by a short-circuit switch between anode and cathode can be deleted again. The extinguishing device 21 is preferably operated manually.

The stored error signal is fed to two safety switching stages 23, 24 and causes a switching process there. These safety switching stages 23, 24 actuate emergency brake valves, not shown in the block diagram, which cause emergency braking of the vehicle. Furthermore, these safety switching stages 23, 24 reduce the setpoint value for fuel injection to the value for idling. This fuel throttle device can be implemented in the simple case by activating a throttle solenoid valve for the fuel by the safety switching stages 23, 24 and is also not shown in detail in the block diagram, but is indicated by arrows.

Instead of the two d ied safety switching stages 23, 24 for the front wheel braking and the rear wheel braking Optionally, further safety switching stages can be switched in parallel through which the wheels Can be braked individually or multiple for a switching process used to increase security d ^ ncn.

A logical NAND switching stage is used to monitor the individual switching stages and supply voltages 25 provided. The inputs of this

Switching stages 25 are signals from both the safety switching stages as well as from acoustic signals that are used to generate or monitor supply voltages, the brake pressures, the driving speed, the steering logic, the braking logic and other logics serve, supplied. If individual stages have K signals in their normal operating state, see above these can be converted to the inputs of the logic NAND-Schaltstufc 25 are supplied. Changes to an input of this switching stage 25 1 signal to an O signal. so this indicates an error. of both the .Speicherstufe 20 for triggering the Braking, as well as a warning device 26, preferably a control lamp, is supplied. The warning device 26 therefore also comes into operation if, due to an impermissibly large deviation from Vehicle from the guide wire, the emergency braking is effectively activated, but a single brake is applied Does not cooperate due to an error. This could evii without the warning device 26. not be remembered at all. It was determined by driving tests that it makes sense to release the steering during emergency braking. For this purpose, the output of the memory stage 20 is connected to a further logic OR switching stage 27 Safety switching stage 28 connected. When this safety switching stage 28 is activated, the steering part device separated from the steering part. For this purpose, a magnetic coupling can be provided or, in the case of a hydraulic coupling Steering adjustment, a solenoid valve can be operated, which reduces the pressure in the servo circuit. These Isolating device is indicated in the block diagram by an arrow and is not shown in detail. Additional error signals can be inputted to additional inputs of the OR switching stage 27 Reason for a signal level that is too low, from the guide wire, a failure or an impermissible value of a Versorgiingsspanniing can be generated.

The signal already described, applied to terminal 14, which is proportional to the signal level of the l.eiidrahies is. is added to each input 'Schwelleertsiufen 29 to 31 are supplied. When the Signal level first addresses the Schwcllwerlstufe 31, at whose output a warning device 32 at If the threshold falls below the threshold, it becomes active. If the signal level drops further, the threshold

'' Value stage 30 in activity that also triggers a warning device υ. Drops the signal level still further and iintci it below a minimal / uliissigen Wen. So speak! The Sehwellwertsuife 29 at. A warning device comes into action at its output 34. Is Furthermore, The output of the threshold stage 29 is connected to an input of the storage stage 20 via a switch 35 and to the inputs of the safety switching stages 23, 24 via a further switch 36. With the switch 36 open and the switch 35 closed

'■ is if the minimum permissible Signal level triggered the emergency brake. Is the switch 35 open and the switch 36 closed, braking only takes place until the signal level returns the critical limit is exceeded. Through the step

¹ 'when the warning devices 32 to 34 are switched on, the respective position of the vehicle in relation to the guide wire can be recognized. The threshold values 29 to 31 naturally also come into operation if the voltage on the conductor wire decreases, if one of the sensors is defective, or if there is a defect in the signal conditioning stage 12.

Further threshold levels can be used for a finer subdivision to the Sehwellwertstuien 29 to 31 are connected in parallel. This can also include threshold levels to indicate that the signal level is too high

'"' to serve.

1 sheet of drawings

Claims (4)

Patent claims: 1. Safety device for an arrangement for tracking of track-free vehicles by means of a electromagnetic field that is laid around one along a driveway of the vehicle Electric current flowing through the guide wire built and scanned by sensors and with over at least one threshold stage controllable safety switching stages for triggering operating processes, characterized in that the amount of a dependent on the deviation of the vehicle from the guide wire, through which Sensors (10, 11) detected the signal together with one of the speed of the vehicle dependent signal of a summing stage (16) can be fed, the output of which with the at least one Threshold level (19) is connected. 2. Safety device according to claim 1, characterized in that one of the alternating ■ voltage amplitude the guide wire voltage dependent signal detected by the sensors (10, U) at least one further threshold level (29, 30, 31) can be fed through which, when the value falls below the Threshold value first safety switching stages (23, 24) can be triggered. \ Safety device according to Claim 2, characterized in that several further threshold value stages (29, 30, 31) are provided, the threshold values of which are staggered and that each threshold value. tufe (29. 30, 31) is assigned a warning device (34,33,32). 4. Safety device according to claim 3, characterized in that the S-hwell value stage (29) provided with the highest threshold value for triggering the first safety switching stages (23, 24)