FR2636750A1 - Signalling and communication system for managing the flow of independent movable objects - Google Patents

Abstract

The present invention relates to a signalling and communication system for conveying independent movable objects guided over a circuit, the said system providing the communication between the central system for control of the flow and the said objects, these objects being equipped with drive means, movement means and means for controlling the said movements, characterised in that: - the said central system is linked to a certain number of communication terminals arranged at defined points over the circuit, - the said objects are equipped with a recognition transmitter allowing them to be identified by each of the said terminals when one of the objects approaches the said terminal, - the terminals in cooperation with the said movable objects are equipped with devices allowing the appropriate stopping and positioning of the said objects with respect to the said terminal. - the terminals are equipped with devices for transmission of orders originating from the said central system, the said orders being received and executed by the said movable object.

Description

Signaling and communication system for managing the circulation of autonomous mobile objects.

 The invention relates to a signaling and communication system for driving autonomous mobile objects.

 By autonomous mobile object, we mean an object that can move by its own means and without human intervention. Said object is therefore provided with drive means (motor for example), displacement means (wheels, skids, etc.) for moving on guide means (rails, wires, etc.) and means for controlling the movement of the object on these guide means (microprocessor on board the object, mechanical control systems by cam sets, etc.).

 The invention applies in the case where these objects are robots responsible for carrying out tasks given at different points of a site, or trolleys carrying loads at different points of the site.

 This can for example be the case of a loading installation on docks for storing products leaving production: several transport carriages are used and rotate on a circuit; depending on their load, they are routed to one platform or another.

 It is therefore necessary to manage the circulation of said autonomous mobile objects, most often by means of a computer or more generally of a central control system which processes the data supplied according to a given program to output instructions for each object therefrom. , said instructions being transmitted to the objects by a signaling and communication system.

 The most common models of industrial conveyor carts employ a guidance process based on the presence of one or more conductive wires embedded in the ground which emit a characteristic electromagnetic signal, used by motor control systems to keep the carriage on the circuit. Depending on the systems, the same wires or specialized wires carry data signals, for example so that a control system communicates with each of the carriages: sending instructions, collecting reports, etc. Still other threads are used as geometric benchmarks, to determine breakpoints, entry into "switches", etc.

 Wire-guided installations have several well-known drawbacks, in particular the rigidity of the installations (metal wires embedded in the ground), and the difficulty of modifying the circuits (because of the density of the wiring).

 When the same wires are used to communicate with the carriages, there are also limitations on the useful data rate, which become critical when the number of carriages sharing a limited number of communication wires is believed, or even just one.

 Finally, signage at intersections, switches, etc. results, in general, in additional wires put in place for this sole purpose, in the multiplication of local automations intended to manage them and / or in a high density of additional wiring (to centralize the desired signals).

 We then thought to get rid of wire-guiding by using other means of guidance: magnetic tapes ... or even intangible paths defined by series of landmarks in space (tags).

 However, it remains necessary to communicate with autonomous mobile objects. Wires have been proposed (but we come back to the disadvantages mentioned above) or radio links (a central antenna transmitting on the site). But if these connections are strictly permissible for isolated machines or in very small numbers, they have many known drawbacks.

 First, the allocation of radio frequencies is strictly regulated, and obtaining them is likely to introduce unacceptable installation delays; we even risk an outright ban. The use of authorized "public" frequency bands comes up against the possible proximity of radio amateurs, remote control transmitters, etc.

 Then, the electromagnetic parasites in industrial environment are very numerous, often badly identified, and evolve in a practically unpredictable way. A system based on the radio, to communicate between robots and control center, can be put out of service overnight by the introduction of new "radiant" equipment on the same site (motors, inductive loads, high frequency heating , etc.).

To overcome these drawbacks, the present invention provides a signaling and communication system for driving autonomous mobile objects guided on a circuit, said system ensuring communication between the central traffic control system and said objects, these objects being provided with drive means, means of movement and means of controlling said movements, in which - said central system is connected to a certain number of terminals
communication arranged at determined points on the circuit, - said objects are provided with a recognition transmitter allows
both their identification by each of said terminals when one
objects approaching said terminal, - the terminals in cooperation with said mobile objects are provided
devices for stopping and proper positioning
said objects with respect to said terminal, the terminals are provided with devices for transmitting orders,
from said central system, said orders being received
and executed by said moving object.

 According to another characteristic of the invention, said terminals and said objects are provided with means allowing objects to transmit information to the terminals, when they are stopped in the order transmission position.

The invention will be better understood from the figures
FIG. 1 represents a circuit for the circulation of autonomous mobile objects, provided with communication terminals,
in FIGS. 2A, 2B, and 2C is shown an advantageous relative arrangement of the detection, identification and communication means placed on a terminal and on an object,
FIG. 3 shows an embodiment of the structure of a terminal,
FIG. 4 schematically shows a connection structure between the central system and the terminals,
- In Figure 5 an embodiment of multiplexer is illustrated.

 On the site shown in Figure 1 to illustrate the invention, there are two production units 1 and 2, and two loading docks 3 and 4. Trolleys (autonomous mobile objects) 5, 6, 7, 8, 9, 10 are responsible for transferring products from units 1 and 2 to platforms 3 and 4 according to a circuit 11. We have even shown in this figure a storage yard 12 for unused carriages.

The circuit 11 can be identified in various ways - iL is materialized by material guiding means such as
rails, wires ....

- or the circuit diagram is entered in the central system of
command and that the circuit has no material existence on the ground
or is made up of intangible paths whose coordinates
were taken in relation to landmarks on the ground (beacons at
known identity for example).

 It is preferred to materialize the circuit by optical strips, means for reading and correcting the direction of the carriage being provided at the level of the carriage and / or of the central control system.

 Each guided trolley (or object) is equipped with - drive means: motor ...

- means of movement on the circuit: wheels, skates ...

adapted to the material guidance means that may be used, - means for controlling its movement on the circuit, said
means which can act on the drive means (stopping, walking,
acceleration ...), on the means of movement (braking, chan
direction ...).

According to the invention, on the circuit 11 are arranged communication terminals 13, 14, 15, 16, 17, 18, 19, 20, which have the function of - detecting the approach of an object and identifying it , transmit information from the central control system to
said object, these are the route instructions (go to such
location), transmit the data (in particular presence of object, identity
object, information from object) to system
command center, possibly receiving information from said
purpose, possibly, of ensuring the transmission of information between
the central system and fixed industrial devices of the site
placed near the terminal.

They therefore ensure in combination with the central control system the communication of information with the mobile object, the signaling: the instructions transmitted are equivalent
at signs "turn right", "stop", etc., and possibly the link with industrial devices
site fixes.

 The location of said terminals on the circuit therefore depends on the signaling and communication needs existing in the various zones of the circuit.

For example, on circuit II: a terminal 20 is placed at the exit of the storage yard 12 for
issue instructions to the outgoing object (communica aspect
tion) and to indicate to him if the way is clear or not (aspect
signage) due to the possible arrival of another object
(noted 9), two terminals 13 and 14 are each placed in front of the
production 1 and 2 to identify the object and, when the charge
ment has been carried out, give him directions.

The object can be stopped in two ways at a workstation (according to Figure 1 at the level of production units and docks) or from the terminal which sends a signal to the object horn
responding to "stop", - either by devices independent of the terminal managed by the
central control system.

 The latter can act on the devices via the terminal, that is to say that the signals are routed from the central system to the terminal which has industrial type inputs / outputs to communicate with fixed industrial devices on the site (machine tools , programmable logic controllers, various sensors, signaling lights for staff use ...). Conversely, industrial devices can send information to the central system, via the terminal.

 The indication that the loading has been carried out generally comes from the industrial device which can transmit to the central system through the industry type inputs / outputs.

The central system thus has means to verify that its orders have been executed - terminals 15, 16, 17, 18, 19 are placed at the branch
to avoid Collisions: they stop the
objects not given priority and provide
of course also if necessary the route instructions to follow.

Terminals 16 and 18 verify the identity of the unloaded trucks
at the docks.

 The terminals can be placed on the sides of the circuit, below and advantageously above, they are then suspended for example on beams, which avoids cluttering the site.

 As a remark, note that circuit 11 is a one-way circuit as shown in FIG. 1. But this particular embodiment cannot limit the invention, in fact outward and return paths may as well be provided or sidings in the case of materialized paths.

Each terminal and each object are equipped with means which cooperate, these are (see FIGS. 2A, 2B, 2C): - means for detecting the presence of objects mounted on each
terminal 26 and each object 23, - means for identifying the object mounted on each
terminal 26, each object having means 23 for its part
allowing to be identified (transmitter of recognition).

 The object presence detection means are preferably disposed on the terminal and the object so that the detection takes place at a distance from the terminal, when the object approaches it. It is the same for the means of identification of the object. This arrangement saves time. The same means can be used for detection or identification, or they can be different means.

 It may be an infrared beam emitted by an infrared emitter placed on the mobile object, each object emitting with a characteristic which is specific to it so as to identify it, said beam being picked up by a compatible infrared receiver mounted on each terminal; the distance at which detection and identification take place varies according to the equipment used, as small as possible, always to avoid pollution of communication by the environment.

It can also be a bar code carried by the object and read by a camera placed on each terminal. Other means are also possible - means 28 carried by the terminal and 29 by the object making it possible to
stop said object in a predetermined position in front of the
terminal, position from which the transmission of orders
can be done.

It can be an "all or nothing" infrared transmitter: if the beam exists, there is a stop, otherwise the object continues on its way - means 30 for the emission of information equipping each
terminal and means 31 for their reception equipping each object,
to transmit orders from the system to the object
central, - possibly, means 33 for receiving information
equipping each terminal and means 32 for transmitting information
tions fitted to each object, in order to transmit information
from the object to the central system.

 These means of communication between the object and the terminal are constituted for example by one or more beams of modulated infrared waves emitted by a transmitter and picked up by a receiver. If you want a dialogue between terminal and object, each must be provided with the pair (transmitter-receiver).

 Other means of communication are possible. For example a looped circuit emitting in radio waves, received by another looped circuit, one circuit being carried by the object and the other by the terminal.

 The transmission of information takes place when the object is stopped vis-à-vis the terminal, which ensures a more secure transmission of information, this transmission is all the better as the distance between terminal and object is lower .

FIGS. 2A, ZB, 2C show a use of the signaling and communication system according to the invention, in which: - the detection and identification (FIG. 2A) of the object 21 have
place at a distance from terminal 22, when the object approaches, thanks
to an infrared emitter 23 mounted on the front 24 of the object and
whose beam 25 is received by a receiver 26 carried on the
side 27 of the terminal, - communication takes place with the object placed opposite the
terminal, the object being stopped
The "stop" information for Object stop is given by a
infrared beam emitted by an all-or-nothing transmitter 28 placed
on terminal 22, signal which, if it exists, is received by the reception
tor 29 located on object 21 (figure 28).

The "stop" information received by 29 is passed on to the resources
of movement of the object which then activate the
drive means and possibly displacement. The judgment
is not immediate. According to said invention, the means of commu
nication are placed on each terminal and each object so
that the stopped object has its means of communication with regard to
those carried by the terminal.

 Thus the object, after stopping, can receive instructions.

The exchange of information (Figure 2C) takes place through one or more
modulated infrared beams, emitted by a modulator and captured
by a demodulator.

According to FIG. 2C, the modulator 30 carried by the terminal 22 transmits
on the demodulator 31 carried by the object 21 to give the ins
directions from the central control system to the object. Eventual
Lement, and it is the case represented on this figure, with a
modulator 32 carried by the object and a demodulator 33 carried by
the carriage, the latter can transmit information to the
thick headed.

 All these detection, identification and communication means carried by the terminal are obviously connected to the central control system.

In addition, each terminal includes - means of transmitting data from and to the
Central system (optical fibers for example), - means to manage the signals in order to select the signal
to send on such means carried by the terminal and to select the
signal carrying information relating to the identified object; these
tasks are carried out preferably by a microprocessor.

 In addition, each object includes means for transmitting the orders received to the means for controlling its movement on the circuit, so that said orders are executed.

 FIG. 3 shows an embodiment of the various members constituting a communication terminal 22. This is equipped with a microprocessor logic 34, of the conventional type, in particular provided with two duplex channels for transmission in series, and with several lines input / output in parallel, the assignment of which can be seen below.

 A first serial channel is connected to the cable with two optical fibers 35 via the receiver 36 and the transmitter 37; it is this link which ensures data transmission with the central control system.

 A second serial channel is connected to the infrared modulator 30 and to the demodulator 33; it is this link which ensures the transmission of data with the moving object in opposite stop position.

Microprocessor logic provides the relay between the two links, offering the double service of speed adaptation and signal regeneration. It is, for example, achievable using the firm's monoblock reference microprocessor 8051
Intel, and the 8274 dual reference transmitter from the same company.

This logic is also connected in parallel - to the digital infrared transmitter 28, for the stop command
Object, - to coded infrared receiver 26, for arrival detection and
identification of the robot, - at the inputs of all-or-nothing states 38, of the "industrial" type (by
example: dry and / or looped current contacts), - at all-or-nothing 39 state outputs of the "industrial" type (by
example: isolated relay or outputs).

 Microprocessor-based logic generically provides you with input and output information, and / or data adaptation (format, speed). It is essentially transparent to the meaning of this information.

 In fairly simple installations, this characteristic allows other processes to share the centralizing network with the conduct of mobile objects, hence savings (on site wiring and on transmission devices, in particular).

 This feature also allows the central system to control the movement of personnel or of controlled vehicles, using devices such as presence sensors, three-color lights, etc., in synchronism with the circulation of autonomous objects. This contributes significantly to the operational safety of sites, where staff and automatic mobile equipment coexist, sometimes in conflict. Traffic lights can be incorporated into the terminal itself.

 FIG. 4 schematically represents an example of a network connecting the communication terminals, and through them mobile objects, with the central control system.

 The central system 39 is a computer equipment of any known type, provided with standard duplex data transmission lines 40, such as the links known under the American acronym RS232C or under the international sign V24.

 Via the multiplexers 41 which concentrate duplex links of the optical fiber type 42, the central system is permanently connected to the dialogue terminals 43.

 In addition, an immaterial data transmission link 44, of the infrared ray type modulated in the preferred embodiment, ensures continuity of transmission between the proper logic of an object 45 and the central system.

 The network constituted by the multiplexers 41 and the links 42 can be replaced by any known type of network ensuring a service of the "transparent data circuit" type (that is to say without modification of the data which pass through this data circuit) , between the central system and the communication terminals.

 The communication protocol addresses the various terminals, as well as the identification and addressing of mobile objects when they are near a terminal. In the preferred solution, a protocol of the type known as "point to multipoint" is used.

 FIG. 4 illustrates a characteristic of a network of communication terminals arranged according to the invention which is to provide, in a predetermined position of the stopped object with respect to any terminal, a data transmission service between this object and the central control system.

 Another desired feature is the speed of the data link, associated with high immunity to industrial noise and rigorous galvanic isolation. This characteristic is obtained in the preferred embodiment by means of fiber optic links.

 FIG. 5 shows by way of indication the structure of a multiplexer 41. This multiplexer is connected to the central system 39 in duplex by a standard link 40, for example a standardized RS232C or V24 junction, via the transmitter 46 and the receiver 47.

 Thanks to gates 48 and 49, the signals are put in parallel with a second auxiliary link, via the transmitter 50 and the receiver 51. This second link is useful for network maintenance: one can in particular attach a traffic analyzer device , without interruption of service.

 The multiplexer is connected to the communication terminals by as many two-fiber optical cables 42, via the transmitters 52 and the receivers 53. The signals transmitted by the central system are broadcast in parallel to all the transmitters 52 via the gate 49, while the signals received from all the receivers 53 are concentrated via the gate with several inputs 54.

Thus a point-to-multipoint type connection is made (in the logical sense), where - the signals transmitted by the central system are broadcast to all
the terminals and / or objects stopped opposite, - the signal sent by only one of the terminals, or only one of the
objects at once, is passed on to the central system.

 Technically, such a multiplexer is achievable using optical transceivers from the firm Hewlett-Packard (of the series referenced HFBR), and usual integrated circuits in logic technologies called "TTL" or "CMOS". The same is true for the optical interfaces of the communication terminals.

  The multiplexer thus described is read; - even from a known principle, as well as the addressing protocols ("polling" in English terminology) which ensure the uniqueness of transmission in return. It completes and illustrates the characteristic layout of the network, intended to establish permanent connections with the communication terminals, and to establish punctual connections with mobile objects.

 The invention described here can be applied to the circulation of any type of autonomous mobile vehicle in various environments. The choice of materials takes this environment into account. A particular application has been presented to product handling carts, it is also advantageous to use the invention for driving robots performing tasks in different places.

Claims (12)

 1. Signaling and communication system for driving autonomous mobile objects guided on a circuit, said system ensuring communication between the central traffic control system and said objects, these objects being provided with drive means, means of movement and means of controlling said movements, characterized in that: - said central system is connected to a certain number of terminals  communication arranged at determined points on the circuit, - said objects are provided with a recognition transmitter allows  both their identification by each of said terminals when one  objects approaching said terminal, - the terminals in cooperation with said mobile objects are provided  devices for stopping and proper positioning  said objects with respect to said terminal, the terminals are provided with devices for transmitting orders,  from said central system, said orders being received and  executed by said moving object.  2. System according to claim 1, characterized in that the identification of the objects is carried out from an infrared beam characteristic of the object emitted by said object and picked up by an infrared receiver being suitably placed on the object respectively. terminal.  3. System according to claim 1, characterized in that the identification of the objects is carried out with a bar code characteristic of the object and carried by the latter, a camera placed in a suitable manner on the terminal making it possible to read it.  4. System according to one of the preceding claims, characterized in that the transmission of orders is ensured from an infrared modulator mounted on the terminal and a demodulator placed opposite the stopped object.  5. System according to one of the preceding claims, characterized in that the transmission of orders is ensured by a transmitter and a receiver of radio orders, placed respectively on the terminal and the object.  6. System according to one of the preceding claims, characterized in that at least part of the terminals have means for receiving the information transmitted by the objects in stop in the position suitable for the transmission of orders.  7. System according to claim 6, characterized in that said means consist of an infrared modulator placed on the object and an associated demodulator placed on the terminal opposite the modulator.  8. System according to claim 6, characterized in that said means consist of a radio command transmitter carried by the object and a receiver on the terminal.  9. System according to one of the preceding claims, characterized in that the object is stopped when a particular infrared beam is emitted by the object, from a transmitter placed on the terminal, a receiver placed on the object and connected to its displacement control means provides Stopping said object in a predetermined position in front of the terminal.  10. System according to one of the preceding claims, characterized in that the terminals include industrial type inputs / outputs.  11. System according to one of the preceding claims, characterized in that the terminals are connected to the central system by means of one or more multiplexers, a multiplexer being able to serve several terminals.  12. System according to one of the preceding claims, characterized in that the circuit is provided with optical strips, and the objects are equipped with means for following them.