EP0113383B1 - Remote control for construction machines, especially for a concrete pump co-operating with a distribution arm - Google Patents

Abstract

For the remote control of construction machinery, more specially in the form of the distribution mast or boom of a concrete pump, in the invention a transmission system has a radio remote control unit whose control transmitter and receiver are joined up with the command unit and with the distributor for the solenoid valves respectively by respective plug contact connector means. The transmission mode is one using digitally encoded RF messages so that for each control function two part-messages are continuously transmitted after the connections have been made, such messages each being made up of a bit representative of the function, of address information and of a parity bit for security, and mirroring the condition of the circuits of the command unit. The receiver has a RF receiving part, a central process controller and a relay part or a D/A converter.

Description

The invention relates to a remote control for construction machines, in particular for concrete pumps interacting with a placing boom, consisting of a portable console serving as a command device, in which several circuits controlled by switches for individual control functions are installed and in which a transmitter for wireless transmission of radio signals is arranged, and a receiving device which has an electrical distributor for several solenoid valves, it being possible to switch from the "remote control" operating mode to another operating mode from the command device.

Concrete pumps of the preferred field of application of the invention are generally speed-controlled in order to adapt the respective delivery rates to the progressive filling of formwork with concrete and can also be reversed in order to fill the delivery line at the beginning of the concreting process and to be able to empty it again after completion. The placing boom is usually built on a column with slewing gear and in turn divided into several sections that can be moved and adjusted independently of one another by hydraulic swivel drives, preferably in the form of thrust piston gears, whereby the concrete discharge in the top of the placing boom is adjusted and adjusted in a horizontal and vertical plane can. Although the invention also applies to other construction machines with a lesser or greater number of control functions, such as. B. earthmoving machines, in particular excavators, can be applied, it is explained in more detail below based on its preferred application.

The radio remote controls known from construction machines with wireless transmission of the control commands mainly use pulse modulation as the transmission type. The receiver belonging to the construction machine supplies the required control voltage at the output. The various interferences have a disadvantageous effect. In particular, interference frequencies of general radio communication, but also strong magnetic fields, which result from the field strengths in the vicinity of high-voltage lines, can lead to uncontrolled boom movements with all the resulting hazards to personnel and materials. Radio remote controls which allow digitally coded HF telegrams as a type of transmission or alternatively a signal transmission in optical fibers are known and can avoid these disadvantages. However, in the known form, they are not suitable for remote control of construction machines.

Known and widely used on construction machines, in particular the special field of application of the invention, are remote controls whose transmission device consists of a multi-core cable which is connected to the plug contacts of the command device and the receiving device. These remote controls have been chosen primarily with regard to their security against inadvertent transmission of control functions. As a rule, they have one wire for each control function. However, they also have considerable practical disadvantages under certain operating conditions.

Since the machine operator is freely near the construction machine to be controlled and has to carry the command transmitter, he must pull the cable behind him. In difficult construction site conditions with the then numerous obstacles, in which the cable often through shafts, windows, staircases, etc. Parts of the building must be pulled through, it is prevented from taking up a location from which he can closely observe the concreting site. He is also at risk if, for. B. Distribution booms with considerable range in the vicinity of high-voltage lines can be manipulated. If there is a voltage flashover, there is a risk to life for the machine operator.

The invention is based on a remote control, as is known from DE-OS-28 41 533. With the help of this control, it is possible to remotely operate and control the construction machine to be controlled wirelessly. If necessary, you can switch from the "Remote control" mode to the "Direct control" mode. Then, however, the operator is forced to approach the machine to be controlled and to operate a control panel located there, which is different from the control panel of the control panel. A problem-free switchover from one operating mode to the other while keeping the portable control panel is not possible with this arrangement. Is z. B. disrupted the wireless transmission, the operator has too little field of vision from the machine so one is forced to control the machine with the help of a multi-core cable or an optical fiber. For this purpose, however, a separate control unit with the corresponding transmission parts must be provided, which leads to a considerable outlay on accessories.

The invention is therefore based on the object of designing a remote control of the type presupposed as known in a simple manner in such a way that its type of transmission can be selected according to the respective operating conditions and optimally adjusted to these.

According to the invention this object is achieved in that the command device has a plug contact to which either a multi-core cable or the transmitter can be connected, which consists of an RF and there is a lightwave transmission part which can be connected to the receiving device via an optical waveguide, a common telegram processor being connected upstream of the lightwave or HF transmission part and a telegram decoder arranged in the receiving device which is connected to an HF or lightwave reception part connected is.

With the invention it is possible to replace the multi-core control cable by the remote control if the safety of the machine operator or the handling of the construction machine can be significantly increased as a result of the omission of the transmission cable between the command device and the electrical distributor. The selected type of transmission of the radio remote control is protected against accidents that emanate from transmitters with radio remote control channels in the vicinity of the construction site because the telegram coding precludes this and a total failure occurs if the carrier frequency is disturbed, but the machine can initially continue to be operated by a cable connection. The invention enables these advantages with the conventional systems, in which it merely replaces the electrical cable in whole or in part, but continues to use the other devices, so that i.a. the expensive command device and the electrical distributor which connects to the solenoid valves need not be changed. The security against the control influences to which known radio remote controls are subject is guaranteed according to the invention by the special type of transmission.

If one wishes to avoid the multicore electrical cable in whole or in part in the event of frequent interference with radio communications, this is preferably done by providing an LW transmitter or an LW receiver in the transmitter and in the receiver and an optical waveguide for connection. Such a transmission path is easy to lay and insensitive to voltage flashovers.

The invention provides for the transmitter to preferably have a separate, portable power source with undervoltage monitoring in the transmitter and for the receiver to have its own voltage supply with undervoltage monitoring. In this case, the electrical connection of the transmitter and the receiver leads to the continuous transmission of the telegrams which reflect the switching state of the command device, but only if the voltage monitors signal sufficient operational reliability and readiness.

• Fig. 1 schematisch die verschiedenen Baugruppen der erfindungsgemäßen Fernsteuerung,
• Fig. 2 ein Schaltbild gemäß einer ersten Ausführungsart der Erfindung, wobei die Schaltung digitale Steuerimpulse liefert,
• Fig. 3 in der Fig. 2 entsprechender Darstellung eine Ausführungsart der Erfindung, welche analoge Steuerimpulse abgibt.
• Fig. 4 ein Schaltbild einer fünfzehnpoligen Betonpumpensteuerung gemäß der Erfindung,
• Fig. 5 eine schematische Wiedergabe der Telegramme,
• Fig. 6 eine Darstellung des Empfängerteils einer Betonpumpe in Form eines Blockschaltbildes und
• Fig. 7 in der Fig. 6 entsprechender Darstellung den Senderteil.

Gemäß der Darstellung der Fig. 1 hat der Maschinenführer 1 zur Fernsteuerung einer nicht dargestellten Baumaschine, beispielsweise einer mit einem Verteilermast zusammenwirkenden Betonpumpe ein als Kommandogerät dienendes 5 tragbares Pult 2 mit je einem Steuerhebel 3 bzw.4 zur Steuerung der ihm optisch auf der Pultoberseite 4a angegebenen Funktionen. Das Innere des Pultes 2 ist in den Fig. 2 und 3 nur teilweise wiedergegeben. Dort sind die insgesamt vier Stromkreise 5 bis 8 dargestellt, die von einem der Steuerhebel 3 bzw.4 durch Auslenkung in den jeweiligen Pfeilrichtungen über Schalter geschlossen bzw. geöffnet werden. Diese Stromkreise enden an einem Steckkontakt 9, der auf der Außenseite des Pultes 2 befestigt ist. Der Steckkontakt 9 ist mehrpolig und läßt sich über einen Stecker 10 mit einem vieladrigen, elektrischen Kabel 11 verbinden, das auf einer Kabeltrommel 12 aufgerollt ist. Das Ende dieses Kabels hat seinerseits einen entsprechenden mehrpoligen Kontakt 13, der an einer mehrpoligen Buchse 14 eines elektrischen Verteilers 15 angeschlossen werden kann. Von dem Verteiler gehen Adern 16 bis 20 aus, die an Magnetventile 21 bis 25 angeschlossen sind. Die Magnetventile können auch von Hand gesteuert werden, was bei 26 bis 30 dargestellt ist. Die Schaltung des hydraulischen Teils führt zur Steuerung über hydraulische Leitungen, welche beispielsweise bei 31 und 32 in Fig. 1 angedeutet sind.Further details, other features and advantages of the invention result from the following description of an embodiment with reference to the figures in the drawing; show it

• 1 shows schematically the various assemblies of the remote control according to the invention,
• 2 shows a circuit diagram according to a first embodiment of the invention, the circuit delivering digital control pulses,
• Fig. 3 in Fig. 2 corresponding representation of an embodiment of the invention, which emits analog control pulses.
• 4 shows a circuit diagram of a fifteen-pole concrete pump control according to the invention,
• 5 shows a schematic representation of the telegrams,
• Fig. 6 is an illustration of the receiver part of a concrete pump in the form of a block diagram and
• Fig. 7 in the Fig. 6 corresponding representation of the transmitter part.

1, the machine operator 1 has, for remote control of a construction machine (not shown), for example a concrete pump cooperating with a placing boom, a portable console 2 serving as a command device, each with a control lever 3 or 4 for controlling it optically on the console top 4a specified functions. The interior of the console 2 is only partially shown in FIGS. 2 and 3. There, the total of four circuits 5 to 8 are shown, which are closed or opened by one of the control levers 3 and 4 by deflection in the respective arrow directions via switches. These circuits end at a plug contact 9, which is attached to the outside of the console 2. The plug contact 9 is multi-pole and can be connected via a plug 10 to a multi-core electrical cable 11 which is rolled up on a cable drum 12. The end of this cable in turn has a corresponding multi-pole contact 13 which can be connected to a multi-pole socket 14 of an electrical distributor 15. Cores 16 to 20 extend from the distributor and are connected to solenoid valves 21 to 25. The solenoid valves can also be controlled by hand, which is shown at 26-30. The switching of the hydraulic part leads to control via hydraulic lines, which are indicated, for example, at 31 and 32 in FIG. 1.

If the electrical transmission cable 11 is not used, the plug 9a is connected with a short connecting cable 33 to a transmitter 34, which is supplied via a short power cable 35 from a battery 36 which the operator 1 wears on his belt 37. The transmitter 34 has a connection socket 38 for the plug contact 40 of an optical waveguide cable 39, the plug contact 41 of which enables the cable 39 to be connected to a receiver 42, which is provided with a socket 44 for this purpose. A short connecting cable 45 connects the receiver 42 to the distributor 15. The distributor is supplied with power via the vehicle battery 46 of a vehicle (not otherwise shown) on which a concrete pump with its distribution mast is built.

As can be seen, the control commands originating from the console 2 can be transmitted in three ways: on the one hand, they are carried out in a conventional manner via a cable 11, the transmitter 34 and the receiver 42 being switched off. Or it takes place via the transmitter 34 and the receiver 42 either via the optical waveguide 39 or wirelessly via the transmitter antenna 47 or the receiver antenna 48.

4 shows the symbols that appear on the cover plate of the portable desk 2. In the order from left to right, the symbols mean the actuation of the individual boom sections via thrust piston gears, the boom being divided into three sections and having a slewing gear. The speed of the pump can also be reduced or increased. Next to it are the symbols for forward and backward running of the pump, which are intended for loading and emptying the concrete delivery line. A stop switch stops the entire system.

The exemplary embodiments shown in FIGS. 2 and 3 show on the transmitter side 34 a telegram processing block with parity formation at 50 and an RF transmission part 51 connected to it, as well as an LW transmission part 52 connected to it to act upon the optical fiber cable 39, an undervoltage monitor 53 and a plug connection 54 to the described external power source 36.

On the receiver side 42, the valve block is shown schematically at 61, which carries the solenoid valves 21 to 25 for the control of the respective thrust piston gears or rotary drives. The receiver 42 has a telegram decoding 56 which is connected upstream of the relay output block 55 via amplifier 57. It receives the telegrams either via the HF receiver 58 or via the LW receiver 59 from the optical fiber 39. In addition, the connection socket of the connecting cable 45 is shown at 43, which can be exchanged for the plug 13 of the electrical connecting cable 11.

The hydraulic system is shown schematically at 60 and works with a 4/3-way valve 61 for double action on a thrust piston transmission 62, the cylinder 63 of which surrounds a piston 64. The hydraulic system is known per se and therefore does not require any detailed description.

While digital control pulses are emitted on line 45 via relay output block 55 in the exemplary embodiment in FIG. 2, analog signal output via a converter 66 and an amplifier or controller 67 is provided in the exemplary embodiment in FIG. 3. Accordingly, the control panel 2 has potentiometers instead of the switches, some of which are shown at 68 and 69 in FIG. 3.

The type of transmission of the remote control according to the invention is explained in more detail below.

In the transmitting section, the control function is transmitted using digitally coded HF telegrams. Each movement is assigned a bit that has the statement stop or movement. In addition, a permanently adjustable address of four bits and a fixed bit are transmitted. The information is saved with a parity bit.

To transmit all information, two partial telegrams are formed, which are shown schematically in the illustration in FIG. 5. They are constructed in such a way that mutually exclusive dangerous states are coded in the corresponding bit, which are checked for antivalence in the receiver. In addition, there is a characteristic bit for the telegram request, which must also be equivalent in the successive telegrams; This means that this bit must change continuously over the entire operating time (transmission time). This is also checked by the receiver part.

By mechanically plugging or screwing on tabs 71 and 72 (Fig. 1) of the transmitter to the console 2, which corresponds to the mechanical connection 73, 74 of the receiver 42 with the distributor 15 or the control block of the solenoid valves 21 to 25, and the Establishing the plug connection at 9, the transmission mode is started, which is indicated by the switch 55 or the switch 75 in the illustration of FIGS. 2 and 3. The transmission of telegrams is continuously maintained until the transmitter is disconnected from the desk 2 by disconnecting the connecting cable 33. A telegram is transmitted every 200 ms. A transmission interruption greater than 0.8 sec., I.e. the failure of more than four telegrams leads to the shutdown of all functions on the receiver.

The content of the telegrams continuously represents the state of the controls on the control panel, e.g. B. represents the control lever 3.4.

The undervoltage monitor 53 described in connection with FIG. 2 in the transmitter 34 ensures that the transmitter is switched off immediately when the operating voltage in the current source 36 falls below the safety threshold. The transmitter can then only be restarted by connecting a fully charged battery. Pressing the emergency switch (see the illustration in Fig. 4 on the right) leads to an immediate permanent interruption of the transmission process. The transmitter is disconnected from the operating voltage, so that another Sending is definitely prevented.

A central processor control, which is shown at 56 in FIG. 2, is located in the receiver in addition to the HF receiver. In the relay part 55 there is a relay for each function which is shown in FIG. 4. The relays correspond to the bits assigned to the respective function in the telegram. Here, the coding of the telegrams, as already stated in the transmission part, is selected so that mutually exclusive states must be equivalent.

The processor controller decodes the incoming partial telegrams and combines them into information telegrams. The information comes in bit-serial. Every single bit is checked for proper length. The preamble bits (cf. FIG. 5) are separated from the data bits and the pause times between the preamble and data and between the sub-telegrams and subsequent telegrams are checked. The address coded in the data bits is compared with the address set on the receiver, the control data bits of the partial telegrams are checked for antivalence, the partial telegrams are checked and the bit change of the identifier bit is examined.

• - Alle Einzelbits müssen die richtige Länge aufweisen;
• - alle Pausenzeiten müssen eingehalten sein, sie dürfen weder unter- noch überschritten sein,
• - es müssen kontinuierlich mindestens acht von insgesamt zwölf Präambelbits erkannt worden sein, was für jedes Teiltelegramm gilt,
• - die gesendeten vier-Bit-Digitaladresse muß in beiden Telegrammen mit der am Empfänger eingestellten Adresse übereinstimmen,
• - die Steuerdatenbits der beiden Teiltelegramme müssen zueinander antivalent sein,
• - das Teiltelegramm-Erkennungsbit muß gewechselt haben,
• - die Parityprüfung über die Datenbits der beiden Teiltelegramme müssen positiv verlaufen sein.

Sind alle diese Bedingungen erfüllt, werden die Steuerbit an die Relais ausgegeben.To recognize valid information and thus trigger a corresponding control process, the following conditions must be met:

• - All individual bits must have the correct length;
• - all break times must be adhered to, they must not be under or exceeded,
• - at least eight of a total of twelve preamble bits must have been recognized continuously, which applies to each partial telegram,
• - The four-bit digital address sent must match the address set on the receiver in both telegrams,
• the control data bits of the two partial telegrams must be mutually equivalent,
• the partial telegram detection bit must have changed,
• - The parity check on the data bits of the two partial telegrams must have been positive.

If all of these conditions are met, the control bits are output to the relays.

If even one condition is not met, the telegram is rejected and the dead man time begins to run. If no telegram pairs that meet the specified conditions are received within 0.8 seconds, all relays are rejected, i.e. all functions are stopped. At the same time, the 30-second time-out begins. If no telegrams are received in these sec. That satisfactorily all tests and contain the information "all operating elements in the rest position", the receiver is finally stopped, i.e. no more telegrams are accepted. The receiver can then only be reactivated by pressing a button on the receiver itself. Before doing so, the transmitter must be switched off. This means that if the transmission / reception path is seriously disturbed, the system must be restarted.

Active undervoltage monitoring ensures that the processor is switched on and off in a defined manner. All relays are dropped.

There is also an emergency stop switch in the relay contact circuit. Further safety is provided by a dead man relay, which also acts in the output relay circuit and drops out if the processor fails. To achieve this, the relay is kept energized by pulses generated by the processor. If the impulses are no longer present or if they shift out of the necessary time grid, the relay drops out and the relay contact circuit is interrupted.

When the receiver starts, the processor checks whether the control of this relay works properly. At the start, the processor expects the control to be in the off state (relay dropped out). If no off state is detected, the other functions are not armed and the system remains at rest.

When the off state is recognized, the processor begins to output the control pulses for the dead man's relay and now expects an on state. If this does not occur, this system is also not activated.

A further security is the active commissioning of the telegram reception by pressing a button. Switching on the operating voltage only has the effect that the test procedures described for the dead man's relay take place, but telegram evaluation does not yet take place. Only pressing a start button on the receiver starts the evaluation of the telegrams. It is also monitored that a key is actually pressed. The off signal on the button line is not evaluated as a start.

A detection is built in to prevent interference from neighboring truck-mounted concrete pumps with the same HF carrier frequency. The transmitter is still switched off when the receiver is switched on. If the receiver receives telegrams that are only formally correct, ie the sequence of preamble and data bits, activation of the receiver by pressing the start button is not permitted. This prevents control commands from being taken over by a transmitter that is already in operation (e.g. another concrete pump). Only when the receiver logic has recognized the RF channel as "free" (ie no telegram-like bit changes) is it activated using the start button enables. The transmitter must now be switched on within 30 seconds to maintain activation.

However, the control function is only started when a telegram (i.e. two partial telegrams) with the information "everything in idle position" has been recognized within 30 seconds. If this does not happen and a telegram with active information is recognized, the receiver returns to the hold state and can then only be started when the transmitter is switched off by pressing a button on the receiver.

This procedure forces defined work to start from the rest position of all operating elements.

After proper start of the transmission and the reception evaluation, as described for the transmission part, telegrams of defined content are expected continuously. A malfunction in the transmit / receive path over a period of 0.8 sec. Switches off all relays and thus shuts down all functions. Faults greater than 30 seconds are considered to be the end of work and lead to a hold state (likewise all relays switched off), which can only be activated by pressing a button on the receiver if the commissioning instructions are followed, i.e. the transmitter is switched, can be picked up again.

As can be seen from the above, the invention has the main advantage that the radio signal transmission primarily provides the greatest possible, optimal security for the operation, function and protection of the operating personnel. In particular, the insensitivity to interference from transmitters with radio remote control channels corresponding to the carrier frequencies is a special feature of the invention. It is excluded by the telegram coding. If the carrier frequency is disturbed, this leads to a total failure of the signal transmission due to the telegram coding, but not to uncontrolled triggering of functions.

If in such a case, which is an emergency, the hydraulic functions still have to be carried out, the optical fiber cable 39 can be used to establish the connection between the transmitter and the receiver. By connecting the telegram processing 50 (FIG. 7) on the operator side and the telegram decoding part 56 (FIG. 6) on the receiving side by means of a single-core, electrically non-conductive optical cable 39 through the interposed LW transmitter 52 and LW receiver 59 (FIG. 2), telegram transmission is possible as an alternative to the radio link while maintaining the same security.

That the connection is possible by simply plugging in the cable 11 at 10 and 13 (FIG. 1) using the otherwise identical components of the radio remote control allows the existing modules to be retained. The remote control by means of cable 11 can, but need not be used.

The invention therefore has the advantage that it enables three types of transmission, which can be used optionally according to the respective conditions of use.

Claims (4)

1. A remote control device for construction machines, especially for concrete pumps cooperating with a distribution arm, consisting of a movable console (2) serving as command apparatus, in which several current circuits controlled by switches are provided for individual control functions and in which a transmitter (34) is provided for the cordless transmission of signals, and receiving apparatus having an electrical distributor (15) for a plurality of electrovalves (21 to 25), wherein the "remote control" mode of the command apparatus (2) can be switched to a different mode of operation, characterised in that the command apparatus (2) is provided with a connector (9) to which either a multi-lead cable (11) or the transmitter (34) can be connected, which consists of a high frequency transmitting portion (51) and a light wave transmitting portion (52), which can be connected to the receiving apparatus by means of a light wave conductor (39), wherein a common message processor is connected in series with the light wave transmitting portion (52) or the high frequency transmitting portion (51) and a message decoder is arranged in the receiving apparatus, which is connected to a high frequency receiving portion (58) or a light wave receiving portion (59).

2. A remote control device according to claim 1, characterised in that digitally coded messages are used in the transmission over the radio or the light wave conductor (39), from which each control function is allocated two continuous sub- messages communicated after production of the connections (9, 10, 13, 14; 38, 40, 41, 43; 47, 48), which comprise respectively a bit allocated to the function, an address information and a parity bit for security and which represent the status of the current circuits of the command apparatus (2), whereby the receiver (42) comprises a receiving portion (58, 59), a central processor (56) and a relay portion (55) or a digital-to-analogue converter (66).

3. A remote control device according to any one of claims 1 or 2, characterised in that a separate, movable current source (36) with a low-voltage monitor (53) in the transmitter (34) is provided for the transmitter (34) and a power supply (46) with a low-voltage monitor (78) is provided for the receiver (42).

4. A remote control device according to any of claims 1 to 3, characterised in that the receiver (39) comprises a dead man's handle (79) and an emergency switch (80) which corresponds to an emergency switch (81) in the transmitter.

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