JPH07174846A - Safety system for construction machine - Google Patents

Abstract

PURPOSE:To prevent the infeasiability of distance detection due to battery exhaustion and assure safety by transmitting the signal indicating the discharged state of a battery from a transponder to a transceiver side. CONSTITUTION:A transceiver 10 is fitted at the rear section of a hydraulic shovel 1, and a transponder 20 is fitted to the helmet of a worker 2. The transceiver 10 has an arithmetic circuit measuring the distance D0 to the transponder 20 and transmits the calculated distance D0 to the control device 4 of a driver's cab 3. The control device 4 compares the distance D0 with the prescribed reference value and drives a warning device on the driver's cab 3 to display a danger when the transponder 20 (worker 2) is approaching. When a battery stored in the transponder 20 is made the consumed state, i.e., the so-called battery exhausted state, the control device 4 reports it to an operator. The transponder 20 has the detecting function of the remainder (discharged state) of the battery and transmits the detected data of the battery remainder to the transceiver 10 side on the transmitted wave.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety system for a construction machine, and more particularly, to a transponder type microwave distance sensor mounted on a construction machine as a safety system so that the operation of a transponder on the other side does not stop. , A safety system capable of ensuring higher safety by monitoring the remaining amount of the built-in battery.

[0002]

2. Description of the Related Art At construction sites, road pavement sites, civil engineering work sites, etc., there are many work modes in which construction machines and workers cross each other. In addition, depending on the location, general people also visit or carry in and carry out various machines used in association with work, and also obstacles. If these workers, ordinary people, obstacles, etc. are in a construction method or in a direction that obstructs the field of view of a driver of a work vehicle or the like, the risk of an accident is extremely high. Therefore,
Therefore, ensuring safety is important. Therefore, various sensors for detecting the position of the other party have been studied, and one of them is a construction machine equipped with a distance sensor using a transponder type microwave.

However, this type of microwave distance sensor mounted on a construction machine is in full-scale application and practical use. On the other hand, taking a hydraulic excavator at a construction site as an example, an operator who operates the hydraulic excavator and a worker who performs auxiliary work around the machine jointly perform construction work. In such a case, it is necessary to secure sufficient safety for work by using the microwave distance sensor. That is, in a hydraulic excavator, a microwave transceiver (transceiver) is mounted on the side of the excavator, and the worker wears the transponder by attaching it to a helmet or the like. Transmission and reception are performed between these, and the position of the worker is monitored.
This informs the operator of the hydraulic excavator that the operator has approached the dangerous area of the hydraulic excavator, and automatically stops the machine as necessary in order to prevent a contact accident between the machine and the operator.

[0004]

When a distance sensor of this type is mounted on a construction machine, the transceiver can be mounted on the construction machine side, so that the operating power can be obtained from the construction machine. On the other hand, the transponder worn and used by the worker currently has to rely on the battery for the electric power because of the wearing relation. At this time, if the transponder battery is exhausted, the distance cannot be detected as a matter of course. Therefore, the safety system described above does not work well. This is because when the distance to the other party cannot be detected, the transceiver side cannot determine whether the battery is dead or the operator is outside the detection range beyond the monitoring range.

[0005] In order to avoid such a thing, in order to inform the operator that the transponder battery is exhausted, a transponder is provided with a display device for the remaining amount, an alarm lamp or a meter is provided. It is to attach. However, with such a display, when the battery runs out during the work, the worker may not be aware that he is focusing on the work. In addition, the method of generating an alarm sound when the remaining amount is low may not be understood by the ambient noise. In consideration of such a situation, in the method of detecting the battery consumption or the battery remaining amount as described above,
We cannot ensure sufficient safety. An object of the present invention is to solve such a problem of the prior art, and to make it possible for the construction machine side to know the remaining amount of the battery of the transponder to prevent the distance detection from being impossible due to the dead battery. It is to provide a safety system for construction machinery that ensures higher safety.

[0006]

The features of the safety system for a construction machine of the present invention for achieving the above object are as follows.
The transponder has a battery that supplies electric power to the transponder, and a first detection circuit that detects a discharge state of the battery, and responds to a signal indicating the predetermined discharge state of the battery detected by the first detection circuit. And a second detection circuit for detecting the signal indicating the predetermined discharge state from the signal transmitted from the transponder, and modulating the received signal and transmitting the modulated signal to the receiver side on the transceiver side. It is a thing.

[0007]

In this way, the transponder is provided with the function of detecting the remaining battery level (battery discharge state) of the transponder,
Since the detection data of the battery remaining amount is transmitted to the transceiver side along with the transmission wave, the remaining battery amount information can be obtained on the transceiver side. Therefore, the construction machine side equipped with the transceiver can detect the dead battery information of the transponder. As a result, the operator who operates the construction machine can determine whether the battery is dead or the transponder side is far away. Further, by doing so, it is possible to take safety measures for running out of battery, such as issuing an alarm to the worker of the transponder running out of battery.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a system configuration diagram of a microwave distance sensor mounted on a construction machine to which a safety system for a construction machine according to the present invention is applied, and FIG. 2 is an explanation of a relation between a transceiver and a transponder of the construction machine. 3, FIG. 3 is an explanatory view of transmission / reception timing, FIG. 4 is an explanatory view of transmission data, FIG. 5 is an explanatory view of a display state of a liquid crystal display panel of a driver's cab, and FIG. It is a flowchart of a display process. As shown in FIG. 2, the transceiver 10 is attached to the rear portion of the hydraulic excavator 1, while the transponder 20 is attached to the helmet of the worker 2.
The transceiver 10 has a distance D0 from the transponder 20.
It has an arithmetic circuit for measuring and sends the calculated distance D0 to the controller 4 of the cab 3. The control device 4 compares the distance D0 with a predetermined reference value, and when the transponder 20 (worker) is approaching a predetermined distance or more, an alarm device on the operator's cab 3 of the hydraulic excavator 1 where the operator is located. To display a danger on the display provided on the cab 3. Furthermore, here, the operator is notified when the battery built in the transponder 20 is in a depleted state, that is, a so-called dead state.

As shown in FIG. 1, the transceiver 10 is provided with a transmitting antenna 10a and a receiving antenna 10b, and a voltage control transmission circuit (VCO) 12 has a frequency within a predetermined frequency range as time passes. A signal having a so-called swept frequency that sequentially increases or decreases by (here, microwave) is generated, and this signal is sent to the transmission circuit 13 to transmit a microwave wave from the transmission antenna 10a, and the same signal is received by the reception antenna 10b. Receiving microwave signals. The radio wave from the transceiver 10 is received by the antenna 20a of the transponder 20, and the radio wave signal entering this is amplified by the receiving circuit 21 to 100 kH.
The output of the z oscillation circuit 22 and the mixing circuit 23 are mixed and transmitted from the antenna 20b to the transceiver 10 via the transmission circuit 24.

The radio signal received by the receiving antenna 10b of the transceiver 10 is amplified by the receiving circuit 14 and mixed with the signal of the VCO 12 by the mixing circuit 15, and the bandpass filter (BP) having a center frequency of 100 kHz is used.
It is input to the phase difference detection circuit 18 via F) 16. The phase difference detection circuit 18 receives the reference signal of 100 kHz from the oscillation circuit 17 of 100 kHz at one input, and the phase of this signal is compared with the signal passed through the BPF 16.

The phase difference G detected by the phase difference detection circuit 18
Is added to the phase change amount detection circuit 19, and the change amount (slope) of the phase difference G is detected here. This amount of change, in other words, the slope of the phase difference G is the transponder 20.
And the distance D0. This slope is a function of the current sweep frequency of the VCO 12 and the sweep frequency when it is transmitted, and corresponds to the round-trip propagation time of the microwave to the transponder 20. The details are described in International Patent Publication No. 63-501981. Therefore, the output of the phase change amount detection circuit 19 is sent to the distance calculation means 30. Here, the distance D0 between the transceiver 10 and the transponder 20 is calculated. The calculated distance D0 is applied to the communication control circuit 31 and is sent to the microprocessor (MPU) 32 mounted on the control device 4 via the communication control circuit 31.

The triangular generator circuit 11 generates a triangular wave control voltage for controlling the oscillation frequency of the VCO 12. As shown in FIG. 3A, the communication control circuit 31 drives intermittently to drive the triangular generation circuit 11 for a period T1 and then stop it for a period T2. The phase difference detection circuit 18, the phase change amount detection circuit 19, and the distance calculation means 30 are also driven for a period T1 by the drive signal from the communication control circuit 31 and operate in this drive period to operate as shown in FIG. Measure the distance as shown. In addition, the communication control circuit 31 controls the entire transceiver 10.

As a result, the frequency generated from the VCO 12 increases from the frequency f1 to the frequency fm during the sweep period T1 as shown in FIG. 3A, and a decreasing transmission wave is generated during the intermittent period T2. Locks the VCO 12 at a constant frequency f0. This frequency f0
The transponder 20 transmits the data indicating the discharge state of the battery to the transceiver 10 during the intermittent period T2 of the frequency. Further, as will be described later, communication from the transceiver 10 to the transponder 20 may be performed during this intermittent period T2. The operation of oscillating the frequency f0 of the VCO 12 is performed at the timing after the communication control circuit 31 stops the operation of the triangular wave generation circuit 11. At this time VCO12
Is supplied with a constant voltage from the communication control circuit 31 to maintain the oscillation frequency f0.

The transponder 20 includes a VCO 25, a demodulation circuit 26, an intermittent period detection circuit 27, and a communication control circuit 2.
8, a detection circuit 29 for detecting the discharged state (or charged state) of the battery, and a battery 40. VCO25
Sends a modulation signal to the mixing circuit 23. The demodulation circuit 26 detects the received signal to detect the triangular wave generation circuit 11
The voltage signal of is demodulated (for example, detected by FM detection).
The intermittent period detection circuit 27 detects the intermittent period T2 from the signal demodulated by the demodulation circuit 26 and generates a pulse P having a width corresponding to the intermittent period T2 (see FIG. 3 (c)).

The communication control circuit 28 includes an intermittent period detection circuit 2
In response to the detection pulse P of 7, the pulse P corresponding to the intermittent period T2 is VCO2 while the pulse P is at the HIGH level ("H").
5 is driven, and the pulse P is at the LOW level for 10
The oscillation circuit 22 of 0 kHz is driven. The detection circuit 29 is
A detection pulse L is generated when the voltage of the battery 40, which is composed of a comparator, drops below a predetermined value. Here, the predetermined value is a limit value of electric power for the transponder 20 to send a transmission signal to the transceiver 10 or a value with some margin, for example, if the voltage of the driving battery is 1.2V. , It is 0.9
It corresponds to the voltage value of V.

When receiving the detection pulse L from the detection circuit 29, the communication control circuit 28 drives the VCO 25.
Therefore, the output signal of the VCO 25 and the signal C of the received radio wave are mixed by the mixing circuit 23 to obtain the received signal C.
Is modulated as a carrier wave. The transmission circuit 24,
It is transmitted to the transceiver 10 as microwave radio waves via the transmitting antenna 20b. Under control of the communication control circuit 28, the VCO 25 is, for example, 110 kHz when the transmission bit is “1” and 1 when the transmission bit is “0”.
The oscillation operation of 00 kHz is performed during the intermittent period T2. There, the carrier wave is amplitude-modulated by 100 kHz and 110 kHz. As shown in FIG. 4 (c), the transmission data at this time is, as a transmission start bit, for example, data of a control signal in which the identification code ID of the transponder 20 is added after the 8-bit all "1" bit data STB. It is generated as a serial pulse D. Then, according to this, the transmission signal is amplitude-modulated and transmitted. Also, other,
Therefore, the communication control circuit 28 has a memory internally storing its own identification code. It also controls the transponder 20 as a whole. In addition, when the information on the discharge state of the battery is transmitted, the frequency of the VCO 25 is 10
This is so-called frequency modulation in which the frequency fluctuates at 0 kHz and 110 kHz.

On the other hand, in the transceiver 10, the radio wave received by the receiving antenna 10b is amplified by the receiving circuit 14 and input to the mixing circuit 15. Here, during the intermittent period T2, the transceiver 10 itself is mixed with the oscillation signal f0 of the VCO 12 that is being generated at that time and synthesized. As a result, the mixed frequency is (twice the transmission frequency of the transceiver + VCO25 of the transponder).
Frequency component) and the VCO 25 frequency), and the component of the VCO 25 is separated through the BPF 16 in accordance with the signal indicating the intermittent period T2 from the communication control circuit 31.

The frequency component separated by the BPF 16 is demodulated by performing FM detection by the demodulation circuit 33 to generate a data sequence of pulse D at the time of transmission. When the pulse D is decoded by the decoder 34, the identification code of the transponder 20 is detected. This allows the battery 40
The identification code signal of the transponder 20 having a voltage value of 0.9 V or less is obtained. This is sent to the MPU 32 via the communication control circuit 31. The decoder 34 performs the operation of detecting the start bit and extracting the identification code after that in order to extract the identification code. As a result, the MPU 32 drives the alarm device 35 and displays on the display device 36 that the battery of the transponder 20 corresponding to the identification code has run out. As a result, the operator contacts, for example, an operator carrying the transponder 20 via a speaker or the like mounted on the hydraulic excavator.

Further, the detection circuit 28 is an A / D conversion circuit that constantly detects the voltage of the battery 40, in other words, a circuit that constantly detects the discharge state (or charge state) of the battery 40. As shown in FIG. 4 (b), the data converted by
You may make it transmit in addition to TA. In this case, the MPU 32 compares the numerical value of the DATA portion of the code from the demodulation circuit 34 with the digital value corresponding to 0.9 V described above, and when the value becomes less than this value, the alarm device 35 is activated. Driven and sent the D
The voltage value indicated by ATA is displayed.

The above is the transponder 2 during the intermittent period T2.
Although the description is centered on communication from 0, in this system, the transponder 20 and the transceiver 10 can communicate with each other during the intermittent period T2. In such a case, the transponder 20 can be made to transmit the state of the battery when receiving a command from the transceiver 10 to transmit the state of discharge of the battery 40. The transmission from the transceiver 10 in this case can be performed as shown in FIG. The command of the transceiver 10 can be written in the position of DATA after the identification code ID of FIG. 4 (b). The transponder 20 decodes the identification code ID from the transceiver 10 by the communication control circuit 28, and when it is its own identification code, when the data written in the position of DATA is a command to transmit the state of the battery. Then, the above-mentioned transmission is executed and transmitted to the transceiver 10.

As described above, according to the present invention, the transceiver has a communication function for transmitting data on the discharge state of the battery between the transponder and the transceiver during the distance measurement time and the distance measurement idle time. At the time of communication, as shown in Fig. 4 (c), the free time can be divided into two, and can be controlled separately from the time from the transceiver to the transponder and the time from the transponder to the transceiver. it can. Since there are a plurality of transponders depending on the situation of use, the mutual communication method between the transponder and the transceiver described above can perform communication with more transponders without competition. If the communication function is not required even during the communication time, the intermittent period T2 is set to zero by measuring the distance. There is an advantage that the transponder does not need to use the communication function.

Transceiver 10 to transponder 20
The communication to is performed at a timing after the communication control circuit 31 stops the operation of the triangular wave generation circuit 11. At this time VC
O12 is supplied with a constant voltage from the communication control circuit 31 and is maintained at a predetermined oscillation frequency f0. Then, the oscillation frequency f0 is modulated to another frequency, for example, fs, according to "1" or "0" of the transmission data. Alternatively, the VCO 12 oscillates at the oscillation frequency f0 according to "1" or "0" of the transmission data.
It may be intermittently oscillated at. Then, the demodulation circuit 26 demodulates this transmission data and sends it to the communication control circuit 28.

When the battery state detection circuit 28 of the transponder 20 is composed of an A / D conversion circuit, the digitally converted data is put on the microwave. Therefore, the transceiver can always detect the remaining battery level and the like. On the hydraulic excavator 1 side, by displaying the state of the battery 40 of the transponder 20 in the state as shown in FIG. 5, for example, the operator can know the discharge state (charge state) of the battery of the transponder 20. In the figure, 35a is a buzzer provided on the operation panel of the cab 3 as a specific example of the alarm device 35, and 35b
Is a LE as a specific example of the alarm device 35 provided in the same manner.
It is a D display element. Reference numeral 36 denotes an LCD display device, and each bar graph represents the discharged state of the battery of each transponder or the remaining amount of charge (charged state) of the battery. Further, 37 is various operation switches.

FIG. 6 shows an MP for performing such a display.
It is a flow chart of control about an alarm and a display which U32 performs. The battery voltage is the specified voltage V0 (= 0.9V)
If it is larger, the timer counter is reset, the warning sound is reset, the LED is stopped, and the machine stop signal is reset. If it is smaller, start the timer counter. Then, when a certain time has elapsed, a warning sound is generated. This warning sound is given to the operator from the buzzer 35a on the operation panel of the control device 4. After the warning sound is generated, the LED 35b is blinked. LED35b
Blinks, for example. Furthermore, when the value of the timer counter is larger than the set time, that is, when the time when the battery voltage is lower than the specified value exceeds the set time,
Set the machine stop signal. The flow of this processing is executed by the MPU 32 of the control device 4. This is done by interrupt calculation at regular intervals. Further, when the distance sensor is not used, interrupt calculation is not performed.

According to such a configuration, since the information from each transceiver is input to the MPU 32 which is the construction machine control device, the discharge amount (charge amount) of the battery of each transceiver.
Is displayed so that the operator can know it. Further, according to the present invention, when the battery charge becomes insufficient, an alarm sound is generated and a warning is given to the operator by blinking the lamp of the control circuit. This alert tells the operator that the worker's battery is dead. The meaning of this alarm is that the operator or the operator can reduce the burden of constantly monitoring the discharge amount of the battery, and the operator can concentrate on the work. In the unlikely event that you do not notice this, after issuing an alarm,
The controller can also cause the construction machine to stop after a certain amount of time.

Since it is constructed as described above,
It is possible to notify the operator before the worst state without constantly monitoring the battery status. Therefore, the burden on the operator is small, and it is possible to prevent the battery of the transponder from running out and prevent the transponder from failing before the battery runs out. These further increase the safety of workers around the construction machine. Needless to say, the transponder may be provided with various alarms and display devices that allow the operator to recognize when the battery is dead. The battery 40 is not limited to the rechargeable battery, and may be a normal dry battery. Also, VCO25
Regarding the frequency of 100kHz, 110k
Hz is just an example, and needless to say, it may be another frequency, such as 100 kHz or 110 kHz.
"1" of the transmission data, the signal of the single frequency of Hz
It is only necessary to intermittently oscillate according to 0 ". In such a case, the oscillator need not be the VCO.

[0027]

As described above, according to the present invention, the transponder is provided with the function of detecting the remaining amount of the battery of the transponder (the discharge state of the battery), and the detection data of the remaining amount of the battery is carried on the transmission wave and transmitted to the transceiver side. Thus, the transceiver side can obtain the battery remaining amount information. Therefore, the construction machine side equipped with the transceiver can detect the dead battery information of the transponder. As a result, the operator of the construction machine can determine whether the battery is dead or the transponder side is far away. Further, by doing so, it is possible to take safety measures for running out of battery, such as issuing an alarm to the worker of the transponder running out of battery.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a microwave distance sensor mounted on a construction machine to which a safety system for a construction machine according to the present invention is applied.

FIG. 2 is an explanatory diagram of a relationship between a transceiver and a transponder of a construction machine.

FIG. 3 is an explanatory diagram of transmission / reception timing.

FIG. 4 is an explanatory diagram of transmission data.

FIG. 5 is an explanatory diagram of a display state of a liquid crystal display panel of a driver's cab.

FIG. 6 is a flowchart of an alarm process and a display process of the control device.

[Explanation of symbols]

1 ... Hydraulic excavator, 2 ... Worker, 3 ... Driver's cab, 4 ... Control device, 10 ... Transceiver, 10a, 20b ... Transmitting antenna, 10b 20a ... Receiving antenna, 11 ... Triangular wave generating circuit, 12, 25 ... Voltage controlled oscillation Circuit (VCO), 1
3, 24 ... Transmission circuit, 14, 21 ... Reception circuit, 15, 2
3 ... Mixing circuit, 16 ... Bandpass filter (BP
F), 17, 22 ... 100 kHz oscillation circuit, 18 ... Phase difference detection circuit, 19 ... Phase change amount detection circuit, 20 ... Transponder, 27, 31 ... Communication control circuit, 28 ... Intermittent period detection circuit, 29 ... Battery discharge Charge state detection circuit, 30 ...
Distance calculation circuit, 32 ... Microprocessor (MPU).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigenori Aoki 650, Kazunachi-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. Tsuchiura Plant

Claims (3)

[Claims] 1. A transmission signal whose frequency is sequentially increased or decreased in a predetermined frequency range is transmitted from a transmitter, and a transponder which receives the transmission signal modulates the reception signal with a predetermined signal and transmits it to the transmitter side. Calculate the distance from the transmitter to the transponder by mixing the transmission signal and the signal of the received wave from the transponder by the receiver on the transmitter side and detecting the rate of change of the phase of the predetermined signal. However, in a construction machine having a safety system that generates an alarm or the like according to the position of the transponder, the transponder includes a battery that supplies power to the transponder and a first detection circuit that detects a discharge state of the battery. Have this first
Is for modulating the received signal according to a signal indicating a predetermined discharge state of the battery detected by the detection circuit and transmitting the modulated signal to the receiver side, and the receiver is the signal transmitted from the transponder, A safety system for a construction machine, comprising: a second detection circuit that detects a signal indicating a predetermined discharge state. 2. An accident prevention process such as issuing an alarm or stopping the operation of a machine when the discharge state detected by the second detection circuit is below a predetermined standard. Item 1. A construction machine safety system according to item 1. 3. The frequency in the predetermined range is microwave and is intermittently swept, and the transponder causes the receiver to perform a predetermined discharge of the battery while the sweep of the microwave is stopped. Send a signal indicating the status,
The safety system for a construction machine according to claim 2, wherein the second detection circuit detects a signal indicating the predetermined discharge state from a signal received from the transponder during the period.