EP0141749A2 - Method for remote control with a direct view of a machine on the yard and transmitter-receiver arrangement adapted for carrying it out - Google Patents

Abstract

1. A direct view remote control method for a construction machine, especially for mines and quarries, adapted to transmit to this machine a plurality of orders to be executed simultaneously, according to which parallel orders from a driver of the machine are converted (LS) into binary signals, a sequential binary signal (A, B-C: Sp -Ss ) is elaborated (CB) from these wherein each sequence includes synchronization bits (A) and information bits (B-C) representative, in biphasic code with a transition per bit, of the afore mentioned binary signals, a remote control signal transmitted in electromagnetic form (ERF) is elaborated (M) by direct amplitude modulation of a carrier wave by this sequential binary signal, from this remote control signal, after reception, the sequential binary signal is restored and converted after synchronization into electrical signals appropriate for control of the machine, the method being characterized in that the sequential binary signal comprises a periodic pulsed signal (A) in its synchronization bits, the frequency of which (H0 ) is an even multiple of the transitory frequencies (H1 , H2 ) defined by the transitions in the successive information bits, and in that on reception the bit and sequence frequencies are restored (RSYN, RM1 ) from the recognition (RSYN), in the demodulated signal, of the synchronization frequency (H0 ), whilst this demodulated signal is subjected (AD; VM, DS) to validation tests, with the help of the frequencies thus restored, before its decoding and conversion into electrical control signal is authorized.

Description

The present invention relates to the direct view remote control of a construction machine or machine adapted to execute pluralities of simultaneous orders. It applies very particularly, but not exclusively, to the remote control of mining and quarrying machines, for example an underground construction machine such as a cutter or a loader-transporter.

As is known, the main purpose of remote control of site machines or machinery is to remove the driver or the pilot of the machine from a work area deemed to be dangerous, or to place in better working conditions.

These objectives appear to be particularly critical in the case of highly dusty work areas, possibly made dangerous by falling blocks, where the driver must be able to control and visually monitor operations while remaining sheltered. This is particularly the case for shearers working in semi-straightening sizes, or trucks working in the racking chamber. It is therefore a "direct view" remote control.

In view of the poor working conditions which have just been mentioned, it goes without saying that it is almost essential that the remote control does not involve any cable liable to be crushed, jammed or cut. This is done, conventionally, by modulation of a carrier wave, intended to pass in electromagnetic form from a transmitter to a receiver, at frequencies selected according to the instructions given by the pilot (see for example the article on "Radio in size" in THE MINERAL INDUSTRY: The Techniques, Suppl. 3-81, March 1981, pages 205-209, PARIS, FRANCE): the information flow is low.

Such remote controls, which continue to be effective, however have drawbacks, in particular because they do not allow the sending of simultaneous orders, which proves to be constraining when it is advisable to control in parallel, for example, the exit from a jack or the rotation of an arm (all or nothing orders) as well as the direction and speed of movement of the machine or one of its elements (variable orders).

There are also known remote control devices suitable for transmitting simultaneous orders, in particular from documents FR-A-2,191,796 or GB-A-1,603,837, but these, which proceed by processing a binary signal , for example in two-phase coding, from all the parallel orders to be transmitted, use an emission frequency per logical level of the binary signal: there is no carrier wave, and the magnetic type coupling established between transmitter and receiver in practice only allows a short range of transmission which may prove to be insufficient to allow the operator to remain safe.

As a general rule, the currently known remote controls are commonly found to be insufficiently reliable, taking into account on the one hand parasites which can alter the electromagnetic waves between transceiver and any obstacles encountered by them, which leads to complex validation circuits. instructions received, and on the other hand the significant power sometimes required for _' transmission, especially in underground sites where the most of the waves emitted are absorbed by the walls, which requires the association with the transmitter of a high capacity power accumulator by means of a flexible cable liable to be damaged.

In addition, these remote controls do not lend themselves to double control, with two transmitters shared between a driver and his assistant; however this need is more and more felt nowadays.

In addition, these remote controls must be designed on a case-by-case basis, depending on the particular machine to be fitted, resulting in high costs and difficulty in repairing in the event of breakdowns.

The present invention seeks to overcome these drawbacks by means of a remote control method suitable for allowing simultaneous transmission of orders with a large operating dynamic and, preferably, high reliability in taking instructions into account, in particular in the case of an emergency stop order, a real autonomy of the transmitter for long periods, and a possibility of double command.

To this end, the invention provides a direct view remote control method of a construction site machine, in particular for mines and quarries, adapted to transmit to this machine, a plurality of orders to be executed simultaneously, according to which parallel orders are converted. of a machine operator in binary signals, a binary sequential signal is produced from these, each sequence of which comprises synchronization bits and representative information bits, in biphase coding, of the aforementioned binary signals, from this signal binary sequential a remote control signal that is transmitted, it is restored from the latter, after reception, the sequential binary signal that is converted after synchronization into electrical signals suitable for controlling the machine, this process being characterized by that the binary sequential signal comprises a periodic slot signal in its synchronization bits, and that the remote control signal results from the amplitude modulation of a carrier wave by this binary sequential signal.

In a preferred embodiment of the invention, for the remote control of a machine comprising a variable control member, a plurality of commands forms an independent group which corresponds to various possible values of an electrical control signal of said member.

It should be noted that taking into account such a variable order supposes that the range accepted for the latter has been made discontinuous, by the arrangement of a plurality of intermediate pads for the positioning of a cursor between extreme positions. . The distribution of these pads can be regular (proportional orders) or have density variations, in particular for the reliable values of the electrical control signal.

According to an advantageous characteristic of the invention, the transmission of an emergency stop order corresponds to the transmission of the synchronization signal during information bits. It is advantageous for this that the frequency of this synchronization signal is an even multiple of the transient frequencies likely to appear in the information bits of the binary signal coded in biphase.

It should be noted that the use of the synchronization frequency for the preparation of an emergency stop signal offers a great guarantee since the emergency stop detection circuits are largely tested in operation. normal when the synchronization signal is detected. Preferably, a prolonged absence of this latter signal causes a "default" stop of the remote-controlled machine.

According to another advantageous characteristic of the invention, the validity of the modulation signal returned to the receiver is tested by exploiting the redundancy of the binary signals in a predetermined number of successive sequences.

According to another advantageous characteristic, the transmission of variable orders only is intermittent, for example for 200 ms per second, with a view to saving the charge of the supply accumulator, which can thus, if necessary, be integrated into the transmitter. The invention however recommends that during intermittency periods, the carrier wave continues to be transmitted, albeit at low power, to allow rapid restoration of synchronization.,

Thanks to the remote control method according to the invention, it is possible to equip a construction machine with several control channels, according to fairly similar carrier waves, allowing, when the need arises, driving with others, by the driver and at least one helper of the device under consideration. Advantageously, the driver retains the monopoly on variable orders and the remote control method of the invention provides for eliminating any variable order transmitted according to a carrier wave different from that granted to the driver.

The subject of the invention is also a transmitter-receiver assembly suitable for implementing the above method.

It should be noted that a transceiver assembly for implementing the method of the invention is modular and scalable.

• - la figure 1 est un schéma d'une séquence d'un signal de modulation selon l'invention ;
• - la figure 2 est un chronogramme représentant l'établissement d'une séquence de modulation en fonction des états binaires des signaux associés aux instructions du conducteur ;
• - la figure 3 est un schéma synoptique d'un ensemble émetteur-récepteur pour la mise en oeuvre du procédé de télécommande de l'invention ;
• - la figure 4 est un schéma synoptique de la partie émetteur de l'ensemble émetteur-récepteur de la figure 3 ;
• - la figure 5 est un schéma synoptique du codeur binaire de l'émetteur de la figure 4 ;
• - la figure 6 est un schéma synoptique d'un ensemble récepteur associé à deux ensembles émetteurs selon la figure 4 associé à une haveuse ;
• - la figure 7 est un schéma synoptique du système de validation et de décodage de la figure 6 ; et
• - la figure 8 est un schéma synoptique d'un circuit d'exploitation de la redondance disposé à la sortie du système de décodage de la figure 7.

Other objects, characteristics and advantages of the invention appear from the following description, given by way of nonlimiting example, with reference to the appended drawings, in which:

• - Figure 1 is a diagram of a sequence of a modulation signal according to the invention;
• FIG. 2 is a timing diagram representing the establishment of a modulation sequence as a function of the binary states of the signals associated with the driver's instructions;
• - Figure 3 is a block diagram of a transmitter-receiver assembly for the implementation of the remote control method of the invention;
• - Figure 4 is a block diagram of the transmitter part of the transmitter-receiver assembly of Figure 3;
• - Figure 5 is a block diagram of the binary encoder of the transmitter of Figure 4;
• - Figure 6 is a block diagram of a receiver assembly associated with two transmitter assemblies according to Figure 4 associated with a cutter;
• - Figure 7 is a block diagram of the validation and decoding system of Figure 6; and
• FIG. 8 is a block diagram of a redundancy operating circuit arranged at the output of the decoding system of FIG. 7.

FIG. 1 shows a sequence of a binary sequential signal used according to the invention for the modulation of a radiated carrier wave in the form of an electromagnetic wave from a transmitter to a receiver. This sequence includes two groups of signals A and B-C. Group A is formed by a periodic binary synchronization signal. The B-C group includes binary signals of variable frequency, which translate the instructions to be transmitted to the remote control machine, previously converted into binary code. Part of the bits (group B) corresponds to a first group of independent orders, for example temporary all-or-nothing orders, while the other part (group C) corresponds to a second group of independent orders, an order variable for example. In this way, a plurality of orders can be transmitted simultaneously.

It is specified that the binary coding of the variable orders requires defining intermediate positions between the extreme values of these orders.

In practice, certain bits can be unused when the overall number of orders to be transmitted is less than the number of possibilities offered by the total number of information bits of each sequence.

In the example in FIG. 1, the sequence is divided into 16 moments: 3 moments are devoted to the synchronization signals (at the rate of 2 slots per moment) and 13 moments are available for the transmission of information. It goes without saying that the number of orders that can be transmitted in parallel is lower the higher the number of different orders to be transmitted.

According to an essential characteristic of the invention, the coding of the information bits is of the biphase type, the value of the binary state coded in each bit of information being translated by the direction of a binary transition in the middle of this bit. : thus a positive median transition corresponds to a binary state 0, and vice versa. The various binary states are specified in FIG. 1 above the serial numbers of the bits in the sequence.

It is therefore observed in FIG. 1 that a succession of alternating binary states (0101 ...) results in biphase coded signals whose frequency, equal to the frequency of the bits, is minimal (denoted f), while that a succession of identical binary states, 0 or 1, results in two-phase coded signals whose frequency is double the previous one (denoted 2f). The frequency of the synchronization signals is an even multiple of the latter, ie 4f in the example proposed.

The square signals at f and 2 f only have harmonics of odd ranks (3, 5 ...) so that the spectral components of the sequential signal concerning the information bits (groups B and C), on the one hand , and synchronization (group A), on the other hand, are quite distinct on the frequency scale. It is this property which makes it possible to extract, from the sequential signal restored on reception, the synchronization signals which are necessary for the decoding of each sequence.

The repetition frequency of the sequences is (f / 8).

By way of example, the invention proposes taking a synchronization frequency at 1700 Hz. The spectral components of the information signals are then preferably 425 Hz and 850 Hz, while that the repetition frequency of the sequences is 53.125 Hz (hence the sequences of 18.87 ms).

As is required for any machine remote control, a remote control method according to the invention is suitable for transmitting an emergency stop AU command. The invention particularly recommends that this signal be a periodic slot signal whose frequency is that of the synchronization signals, ie 1700 Hz in the example of FIG. 1.

The principle of the binary coding operations is detailed on the timing diagram of FIG. 2.

• - H₀ de fréquence 4 f (1700 Hz) ;
• - H₁ et H'₁ de fréquence 2 f (850 Hz) avec toutefois un déphasage d'un quart de période de retard entre H'₁ et H ₁ ; et
• - H₂ à H₅, correspondant à des fréquences f, f/2...f/8 qui servent pour la définition des séquences.

Various clock signals are necessary for the establishment of the sequential signal, obtained by repeating divisions by 2:

• - H ₀ of frequency 4 f (1700 Hz);
• - H ₁ and H ' ₁ of frequency 2 f (850 Hz) with however a phase shift of a quarter of delay period between H' ₁ and H ₁ ; and
• - H ₂ to H ₅ , corresponding to frequencies f, f / 2 ... f / 8 which are used for the definition of the sequences.

The line "n" corresponds to the sequence numbers of the 16 moments of a sequence, while the line "C" corresponds to the binary states of the control orders during the last 13 moments of the sequence.

A binary signal S _B is established which takes up the signal H ' ₁ during the first three moments, then takes a zero level for the binary states 0 of C and a maximum level for the values 1 of C.

A primary sequential signal S is then established, the level of which is maximum when S _B and H ₁ are both maximum and minimum, or minimum when S _B and H ₁ are of different levels.

A sequential output signal S _s is finally established, after taking into account a possible emergency stop order, which appears during the moment 11 of the sequence represented in FIG. 2. The signal S _s takes again the value of the primary sequential signal S p as long as the AU signal is zero. As soon as the latter becomes maximum, the signal H ₀ is substituted for S in S. It is this signal S which is used for the modulation of the radiated carrier wave between transmitter and receiver.

FIG. 3 schematically illustrates the structure of a transmitter-receiver assembly for implementing a remote control method according to the invention. The transmitting part E is shown at a smaller size than the receiving part R to indicate that the transmitting part is generally portable and therefore smaller, a priori, than the receiving part which is stationary on the machine.

Only the main components of the transmitter E and of the receiver R have been shown diagrammatically in FIG. 3. Thus, the driver's orders are introduced into the transmitter E via a PC console provided with switches, switches , sliders and appropriate pushbuttons. The orders received by the control desk are processed by a specific LS logic of the machine to be controlled which "filters", groups and channels the orders given so as to only retain, according to pre-established priority rules, only compatible orders and likely to be issued simultaneously. Possible control errors, for example by parasitic pressing on two keys at the same time, can thus be avoided.

The orders transmitted by the specific logic LS in binary form then pass through a binary coder CB which ensures the two-phase coding of the orders in successive bits within successive sequences. The sequential signal is then transmitted to a modulator M, preferably adapted to act in amplitude, at 60%, followed by an ERF radiofrequency transmitter equipped with an antenna A. The power required for the operation of the transmitter part is provided by a BA accumulator block adapted to produce the energy necessary for at least the duration of a work station (8 hours in general).

The carrier wave radiated by the transmitter ERF is received by the antenna A 'of a receiver element RRF of the receiver part R, which supplies a demodulated signal to a decoding authorization stage AD intended to verify criteria of predetermined validity. After authorization, the demodulated signal is decoded in a binary decoder DB. The binary orders thus obtained in parallel are processed by a specific logic LS 'followed by an output stage S connected to the control members of the remote-controlled machine. This receiver part R also comprises a supply stage AR; it is possibly connected to the sources on board the machine.

The main elements of the transmitter-receiver unit are specified below, in the context of an application to the remote control of a cutter in one size.

It is specified first of all that at frequencies of around 160 MHz, the electromagnetic field commonly weakens, in an underground site, by 20 dB over 10 meters, while additional losses, which can be estimated roughly 30 dB, can occur due to an unfavorable orientation of the transmitter antenna compared to that of the receiver, or a mask effect due to obstacles. Taking into account the sensitivity of the radiofrequency receiver (1 microvolt at least, for a single remote control channel), the efficiency of the antennas and the aforementioned losses, it is calculated that, to ensure a range of 15 meters in underground workings between transmitter and receiver, an emission level of 100 mW is required, which implies significant consumption.

By principle, the specific LS logic of the transmitter and that of the receiver are non-standard elements which are defined for each particular case of a remote control machine.

• - 1 ordre variable : affichage du sens et de la vitesse de marche au moyen d'un commutateur ou curseur, à 31 positions par exemple, et
• - jusqu'à 15 ordres tout ou rien non simultanés, au moyen de boutons-poussoirs.

However, the specific LS logic of a cutter remote control transmitter can be standardized insofar as the order of the currently known cutter models can be reduced to:

• - 1 variable order: display of the direction and speed of travel by means of a switch or cursor, with 31 positions for example, and
• - up to 15 non-simultaneous all-or-nothing orders, using push-buttons.

The remote control of a cutter therefore requires only 9 bits of information: 4 bits for all or nothing orders (2 = 16> 15) and 5 bits for variable order (2 ⁵ = 32> 31). All of the 13 bits of information are therefore not essential.

FIG. 4 shows diagrammatically the mounting of the various constituent elements of a transmitter assembly E according to FIG. 3.

The PC console has push buttons BP, a variable order switch COV, an emergency stop button AU and a start button MM.

The start button controls the supply of the transmitter E by its accumulation block BA. A “battery cut-off” circuit CA advantageously causes the specific logic LS and the binary encoder CB to be turned off when the supply voltage delivered by the accumulation block becomes less than a threshold (8.9 V for example for a set voltage of 9.6 V). There is no longer any issuance of order and thus avoids any issuance of false order.

Figure 5 shows the arrangement of the main components of the binary coder CB. This encoder comprises a clock HG and a parallel-series converter CPS, the first three inputs 1 to 3 of which receive the clock signal H ₁ ¹ ; the other 13 inputs 4 to 16 are connected to the output of the specific logic. This CPS converter also receives, in particular, the signal H ₅ which defines the conversion frequency according to which it must work. It delivers at its output the signal S _B defined in connection with FIG. 2 according to the states of its inputs 4 to 16, which is applied to a two-phase CBF coder which, after combination with the clock signal H ₁ , delivers the primary binary signal S. A selector S delivers at its output a signal S which takes up either S or the signal H ₀ , depending on whether the signal AU which is applied to it is zero or not.

The signal S _s is applied to the modulator M which acts accordingly on the radiofrequency transmitter ERF.

The modulator M and the transmitter ERF are advantageously placed under the control of a transmission control circuit CE, itself placed under the control of the specific logic and of the emergency stop push-button AU.

Indeed, according to an advantageous characteristic of the invention, the transmission is intermittent, for example for 20% of the time (200 ms per second). Thus, a power supply of the type (9.6 volts - 450 mAh of nominal capacity) which, for a consumption of the transmitter of 70 mA, would have an autonomy of only 6 hours, allows an autonomy greater than the duration of a workstation, with an average consumption which can be estimated at 25 mA.

The invention further recommends that this chopped transmission mode be replaced by a permanent transmission mode as soon as a change, identified by the specific logic, occurs in the orders. Thus, the permanent transmission is restored for a predetermined time (0.5 s for example) for any change of permanent order (variable order such as direction and speed of travel), or during the time of pressing the buttons- pushbuttons for temporary orders (all or nothing orders of cylinders or contactors for example). The permanent transmission is of course restored in the event of an emergency stop. In this way, the speed of the response and operational safety are guaranteed.

We can estimate that during an 8-hour workstation, the total duration of successive orders given with a transmitter is around 2 hours. (3 hours maximum). It is then found that the discharge of a power supply unit of the aforementioned type is from 65% to 75% of its capacity, which leaves a good margin of safety and autonomy even if the power supply unit is used.

The control of these two transmission modes, chopped or permanent, is ensured by the transmission control circuit CE as a function of the signals of the push button AU and of the specific logic LS responsible for detecting any change in the orders all or nothing (temporary) or permanent (variables). A VE LED advantageously lights up in the event of emission.

It should be noted that the chopped or intermittent transmission mode is compatible with the default stop condition, generally imposed on machine remote controls, as long as the maximum absence time, beyond which the order to stop is issued, is clearly greater than the duration of the periodic intermittences, more than 2 seconds preferably in the example considered.

Preferably, during intermittent periods in intermittent transmission mode, the transmitter delivers an unmodulated signal (carrier frequency only) at a level of around 1 mW instead of 100 mW of power (for 50 Ω) in emission. This carrier frequency transmission mode, on standby, has the advantage of consuming very little current, which is the reason for intermittent transmission, while ensuring, upon reception, a recovery fast synchronization.

The carrier frequency is chosen from the VHF range of very high frequencies and is advantageously between 154 and 174 MHz (156 and 165 MHz preferably).

FIG. 6 is a diagram of a receiver assembly adapted to ensure the remote control of a cutter from two transmitters of the type described in connection with FIG. 4. This receiver assembly comprises two receiver parts R ₁ and R ₂ connected to a same antenna A '.

The receiver assembly is contained in an explosion-proof envelope PA provided with a coaxial crossing plug TC adapted to not induce mismatch on the antenna link A '.

The signals received by the antenna A ′ are first processed by an antenna splitter SA adapted to separate the signals from the two channels used (156 and 165 MHz in the example considered) so that at the input of each RRF1 or RRF2 radiofrequency transmitter, the signal from the other channel arrives with a limited level. The separator includes a power divider and two channel filters.

The receivers RRF1 and RRF2 are receivers of the superheterodyne type with double frequency change and include a silence circuit ("squelch") adapted to authorize the output of the demodulated signal only when its level is above a threshold, of 2Veff per example; as well as a very effective automatic gain control device to give them very high input dynamics. These receivers are set so as to require in intermittent transmission mode, thanks to the permanence of the carrier wave, only a transient response time of 30 ms, which remains low compared to the 200 ms of each cycle d 'program.

The RRF1 and RRF2 receivers deliver at their output signals, a priori equivalent to the modulation signals from the transmitters, which are supported by decoding stages whose schematic structure is specified in FIG. 7.

This signal delivered after demodulation by the receiver RRF1 or RRF2 first crosses an MFC circuit for shaping and calibration in amplitude which converts it into a binary signal. This is, in fact, not strictly similar to the signal delivered by the binary encoder of the transmitter, in particular due to the vagaries of propagation of the modulated electromagnetic wave (permanent variations in the level of the received signal), noises , electromagnetic interference, and distortions introduced by electronic circuits. The binary decoder DB is therefore advantageously associated with recognition circuits adapted to identify these alterations and to eliminate them or to interrupt the decoding.

It appears from FIG. 7 that the stages of authorization of decoding AD and binary decoding DB are in fact parallel.

The main point of decoding is the recovery of rhythms in order to precisely define the start of each sequence, and of each bit in each sequence, so as to correctly control successive conversions of the calibrated signal, as delivered to the output. of the MFC circuit, in parallel control commands that can be used to control the appropriate components of the machine in question.

The calibrated binary signal is thus applied to synchronization circuits RSYN and RH1.

The purpose of the RSYN circuit is to recover the frequency of renewal of the sequences in the calibrated binary sequential signal so as to command a series-parallel conversion at the start of each sequence. This circuit selects, in the frequency spectrum of the calibrated binary signal, the components at the frequency H ₀ of the transmitter (1700 Hz in the example considered) so as to establish a binary signal SYN which is at the maximum level in the presence of components at H ₀ , or at the zero level in the absence of these. The 6 synchronization signals with which any sequence normally begins correspond to a maximum value of the SYN signal, which then becomes zero again: each positive transition (0 to 1) of this SYN signal therefore corresponds to the start of a sequence, and serves as a signal triggering conversion for a serial-parallel conversion CSP circuit to which the calibrated binary signal delivered by the MFC circuit is also applied.

In the presence of the emergency signal AU, which admits a single spectral component equal to H ₀ , the SYN signal remains blocked at its maximum value: no positive transition can then be transmitted to the CSP converter. This permanent maximum value of SYN is identified by a circuit DAU for detecting an emergency stop order, and the signal AU delivered by the latter becomes non-zero.

The circuit RH1 ensures a setting in synchronization with the frequency H1 of repetition of the bits in each sequence. This synchronization in synchronization is not immediate insofar as the sequential signal admits various spectral components. This calibration can be carried out by generation of a pulse for any transition of the calibrated signal, by suppression of the pulses due to the negative transitions associated with the frequency H0, by the excitation of a band-pass filter whose central frequency is H ₀ , by generating a pulse for any zero crossing of the response signal of said filter and by counting the latter so as to recover the frequency H1, with a phase defined by synchronization with SYN. The binary signal thus obtained is noted H1.

The converter CSP, for which the signals H1 and SYN serve as clock signals, is also placed under the control of a validation signal VAL emitted by the decoding authorization circuit AD.

In the example of FIG. 7, the circuit AD consists of two circuits VM and DS each adapted to test a criterion of likelihood of the calibrated binary sequential signal.

The VM circuit establishes the average value of the amplitude of the calibrated signal. Taking into account the biphase coding recommended by the invention, this average value must be at half of the maximum level of the binary signal

The circuit DS measures, on the basis of the signal S _Y N established by the circuit RSYN, the average duration of the sequences and compares it with the predictable value from the frequency H5 of the transmitter.

An AND gate is connected to the outputs of the circuits VM and DS and delivers to the converter CSP a trigger signal VAL which remains at a non-zero level as long as the likelihood tests established by the aforementioned circuits are satisfied. Otherwise, any conversion of the calibrated binary signal is prohibited.

A conversion takes place for each sequence. The 13 bits of each sequence are delivered to the 13 parallel outputs of the CSP converter and remain stored there until the arrival of the result of the next conversion.

According to an advantageous characteristic of the invention, the specific logic LS of the receiver assembly of FIG. 6 comprises an additional validation circuit CER, for each channel.

The principle of these CER circuits is illustrated in FIG. 8. The purpose of these circuits is to exploit the redundancy that the binary sequential signal normally presents, since the control orders must be found in several consecutive sequences; according to the invention, any change of state in one of the order bits of a sequence is only taken into account if this new state is maintained for a predetermined number, 4 for example, of consecutive sequences.

In accordance with FIG. 8, the output signals of the converter CSP are applied to RC circuits which realize, independently for each bit, an average pseudo-value permanently defined on the. last sequences. Threshold comparators T transform these analog signals into binary signals which are stored at each sequence in a memory MER receiving the clock signal SYN. This memory delivers signals only insofar as the binary states received successively have been identical during a sufficient number of sequences.

This MER circuit is placed under the control of an OR gate which controls the zeroing of its outputs when one of the VAL or AU signals requires it.

It should be noted that the use of redundancy leads to a very short order execution time, completely acceptable (around 100 ms) even in the event of chopped or intermittent transmission where each transmission cycle which lasts 0.2 s, includes more than 10 sequences.

The absence of validation of the sequential signal for a predetermined time (between 2 and 9 s preferably) noted by a timer, for example associated with the CER circuit, advantageously causes a default stop of the machine in the same way as a command of 'emergency stop. A general stop order AG is sent to a stop circuit CA.

The output signals from each CER circuit are distributed between a VIT circuit for taking variable orders into account, and a T / R circuit for taking all or nothing orders. These circuits are placed under the control of a CD delegation switch by which the delegation rules between the two transmitters are defined. This switch preferably admits four positions: remote control according to one or the other only of the channels (156 or 165 MHz) or remote control with two pilots with priority to one or the other of the channels. In practice, even in the case of a remote control with two pilots, only one of the channels is authorized to transmit variable type orders. These VIT and T / R circuits include memories for taking these delegation rules into account.

Provided that the delegation rules are satisfied, the VIT circuit delivers an analog reference signal intended for a servomechanism controlling the running speed of the machine. Advantageously, the intermediate speeds corresponding to the variable orders transmitted by the transmitter-receiver unit, rather than being regularly distributed between the extreme speeds, are grouped in the range of low speeds so as to allow the pilot great precision in its low speed control of the machine. These speeds are preferably all the more spaced as their level is high. The order-speed correspondence law desired by the user is fixed by means of a programmable memory of the circuit VIT of the logic LS '.

The T / R circuit, in combination with an EV stage, controls the appropriate parts of the machine, such as solenoid valves.

The machine preferably includes a PCM manual control console.

It goes without saying that the above description has been offered only for illustrative purposes and that numerous variants can be proposed by those skilled in the art without departing from the scope of the invention.

It is also understood, moreover, that the details of making a transmitter-receiver assembly for implementing the invention are within the reach of those skilled in the art.

It is specified in particular that the number of 13 bits of information mentioned in the description has no compulsory character, this number being fixed only by the capacity of the series-parallel and parallel-series converters used.

The invention has been described with regard to a cutter, adapted to receive simultaneously two orders at most, one variable (permanent), the other all or nothing (temporary). It goes without saying that the invention applies equally well to the control of a machine, such as a loader-transporter, adapted to receive several simultaneous all or nothing orders. It suffices, within the specific logic of the transmitter, to share the bits of information available in as many groups as there are orders capable of being transmitted simultaneously. Thus, in the case of a machine capable of receiving n simultaneous orders chosen from N, the available information bits will be divided into at least n groups corresponding to an equivalent number of groups of independent orders. It is recalled that certain bits of information may remain unused. If necessary, each bit corresponds to a bit. According to the priority rules imposed on the specific logic of the issuer, the maximum number of simultaneous orders is less than or equal to the number of groups of independent orders.

The invention is of course applicable to a number of remote control channels greater than 2.

Claims (17)

1. Direct view remote control method of a site machine, in particular for mines and quarries, adapted to transmit to this machine a plurality of orders to be executed simultaneously, according to which parallel orders of a machine operator are converted in binary signals, a binary sequential signal is produced from these, each sequence of which comprises synchronization bits and representative information bits, in biphase coding, of the aforementioned binary signals, it is produced from this binary sequential signal a remote control signal that is transmitted, it is restored from the latter, after reception, the sequential binary signal that is converted after synchronization into electrical signals suitable for controlling the machine, this process being characterized in that the binary sequential signal comprises a periodic slot signal in its synchronization bits, and that the remote control signal results from the amplitude modulation of a carrier wave by this binary sequential signal. 2. Method according to claim 1 for the remote control of a machine, such as a cutter, comprising a variable control member, characterized in that a plurality of orders constitutes a group corresponding to various possible values of an electrical signal of control of said variable control member. 3. Method according to claim 2, characterized in that said possible values of the control signal are further apart the higher their level. 4. A remote control method according to any one of claims 1 to 3, characterized in that the frequency (H0) of the binary synchronization signals is an even multiple of the transient frequencies (H _l , H ₂ ) defined by the transitions in the successive bits of information. 5. remote control method according to any one of claims 1 to 4, adapted to transmit an emergency stop signal, characterized in that the emergency stop signal (AU) is a binary signal identical to the signals synchronization (H _O ) but occupying information bits. 6. A remote control method according to any one of claims 1 to 5, characterized in that, after the restitution of the modulation signal from the electromagnetic wave as received, said signal is subjected to validation tests before d '' authorize its decoding and its conversion into electrical control signals. 7. A remote control method according to claim 6, characterized in that the decoding of the binary sequential modulation signal is authorized only if the average duration of its sequences corresponds to that of the sequences before modulation of the carrier wave, and if its average value is half of its maximum level. 8. A remote control method according to claim 6 or claim 7, characterized in that a default stop order is transmitted to the machine when no decoding authorization has taken place for a predetermined time. 9. A remote control method according to any one of claims 1 to 8, characterized in that, after the conversion of the restored modulation signal into parallel binary signals, the information which these contain, when they correspond to changes of orders, are only taken into account if they are repeated identically during a predetermined number of successive sequences. 10. A remote control method according to any one of claims 1 to 9, characterized in that the remote control signal obtained by modulation of the carrier wave is transmitted intermittently by cycles of several successive sequences. 11. A remote control method according to claim 10, characterized in that, between the transmission cycles, the carrier wave, unmodulated, is transmitted at a power of approximately 100 times lower than the normal transmission power. 12. A remote control method according to claim 10 or claim 11, characterized in that the transmission of the remote control signal becomes permanent again when a change of order. 13. Remote control method according to any one of claims 1 to 12, characterized in that the carrier wave has a very high frequency between about 154 and 174 MHz. 14. A remote control method according to any one of claims 1 to 13, characterized in that the sequences have a frequency of approximately 53, 125 Hz and that the synchronization signals have a frequency of approximately 1700 Hz. 15. Remote control method according to any one of claims 1 to 14, characterized in that a plurality of at least two remote control signals is produced by modulating a plurality of carrier waves respectively associated with a plurality of conductors and that, after reception of these remote control signals, the orders thus transmitted are validated according to predefined rules of delegation between conductors. 16. transceiver assembly suitable for implementing a remote control method according to any one of claims 1 to 15, characterized in that it comprises at least one transmitter (E) comprising a control console (PC ), associated with a specific logic (LS) adapted to put in binary form the instructions of the machine pilot, a binary coder (CB) for the establishment of the binary sequential modulation signal associated with a modulator (M) and a radiofrequency transmitter (ERF), and in that it comprises a receiver part (R) comprising at least one radiofrequency receiver (RRF), a binary decoder (DB) associated with a decoding authorization circuit (AD) and specific logic (LS ') adapted to generate analog signals control for the machine. 17. transceiver assembly according to claim 16, characterized in that it comprises two transmitters set to two neighboring carrier wave frequencies, and that the receiver part comprises an antenna selector (SA) adapted to distribute the signals of remote control between two receivers (RRF1, RRF2) each associated with a carrier wave frequency, and two binary decoders (DB), connected to a unique specific logic adapted to take into account binary signals as decoded according to delegation rules between transmitters fixed by the position of a delegation switch (CD).

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