CN101870295A - A derailment detection device for a large road maintenance vehicle - Google Patents

Abstract

The invention relates to a derailing detector for a large road maintenance vehicle. The derailing detector comprises an ultrasonic distance sensor and a processor; the ultrasonic distance sensor is arranged on the bottom of the large road maintenance vehicle and directed at the surfaces of railroad rails; the processor is used for receiving and processing a distance value transmitted by the ultrasonic distance sensor; and the processor selects the following actions: when the current distance value transmitted by the ultrasonic distance sensor is larger than or equal to a set value, transmitting an alarm signal; or when the current distance value transmitted by the ultrasonic distance sensor is less than the set value, processing a next distance value transmitted by the ultrasonic distance sensor. The derailing detector can actively detect whether the large road maintenance vehicle is derailed or probably derailed, and can transmit an alarm signal when the large road maintenance vehicle is derailed or probably derailed.

Description

A derailment detection device for a large road maintenance vehicle

technical field

The invention relates to a rail vehicle, in particular to the field of safety protection of a large-scale road maintenance vehicle (such as a cleaning vehicle, a tamping vehicle, etc.) in a railway maintenance department.

Background technique

Large-scale road maintenance vehicle is a kind of train. During the construction process, large-scale road maintenance vehicle, like ordinary trains, often derails. However, the existing relevant achievements mainly focus on the train derailment phenomenon under the environment of high speed, heavy load, mixed passenger and freight, bridges, and empty trucks. The methods adopted are extremely complicated and there are many factors considered. The derailment of the work vehicle is not practical for the following reasons:

(1) The running speed of the large-scale road maintenance vehicle is very slow, there is no emergency braking when the external conditions are bad, the running speed of the train exceeds the rated speed, the unreasonable suspension stiffness and torsional stiffness of the vehicle body, and the full train no-load under the speed-up state Preconditions such as trucks and light and heavy trucks are mixed, and it is impossible for the phenomenon of derailment and derailment of the slide rail;

(2) The operating mode of large-scale road maintenance vehicles is different from that of conventional passenger and freight trains, and is usually constructed while running, so the wheel-rail contact and force relationship between the working vehicle and the rail is very different from that of conventional passenger and freight trains;

(3) The early warning device developed according to the existing achievements has high cost and complex parameter setting, and can only play an alarm or early warning role (taking into account false positives or missed negatives), so that when derailment is detected Send a signal to the train driver to take corresponding measures, and cannot stop automatically.

Due to the above defects, there is no derailment detection method and device suitable for large-scale road maintenance vehicles at present. The domestic solution to the derailment of large-scale road maintenance vehicles is to use a rerailer or a recovery device to recover the vehicle after it has derailed. This method is an emergency measure taken after the derailment of a large-scale road maintenance vehicle, and belongs to a passive post-event rescue treatment method.

However, due to the unpredictable impact and loss caused by the derailment of the large track maintenance vehicle, in some cases, even if the derailed large track maintenance vehicle is successfully recovered by using a rerailer or recovery device, the delay caused The loss caused by the derailment of the large road maintenance vehicle is still unavoidable.

Contents of the invention

The technical problem to be solved by the present invention is to provide a derailment detection device for a large-scale road maintenance vehicle, which can actively detect whether a large-scale road maintenance vehicle is derailed or whether it may derail, and send an alarm signal when the derailment or possible derailment occurs.

The technical scheme that the present invention takes for solving the problems of the technologies described above is:

A derailment detection device for a large-scale road maintenance vehicle, characterized in that it includes:

The ultrasonic distance sensor set on the bottom of the large road maintenance vehicle and pointing to the rail surface,

A processor for receiving and processing the distance value sent by the ultrasonic distance sensor;

The processor selects from the following actions:

When the current distance value sent by the ultrasonic distance sensor is greater than or equal to the set value, an alarm signal is sent;

or,

When the current distance value sent by the ultrasonic distance sensor is less than the set value, process the next distance value sent by the ultrasonic distance sensor.

In the above solution, the ultrasonic distance sensor is an ultrasonic distance sensor with a temperature compensation function.

In the above solution, the ultrasonic frequency emitted by the ultrasonic distance sensor is 250KHz.

In the above solution, the ultrasonic distance sensor includes an ultrasonic probe and a processing module. The ultrasonic probe receives the ultrasonic echo and outputs a voltage signal to the processing module. The frequency of the voltage signal processed by the processing module is between 200-300KHz, and the amplitude is between 2.5-3.3 between v.

The working principle of the present invention is as follows: the ultrasonic sensor is used to accurately detect the distance between the ultrasonic sensor installed at the bottom of the large-scale road maintenance vehicle and the rail surface, and when the distance between the ultrasonic sensor and the rail surface is greater than or equal to the set value, it indicates that the large-scale road maintenance vehicle has derailed When derailment occurs, the derailment detection device of the large-scale road maintenance vehicle of the present invention sends out an alarm signal to alarm.

The beneficial effects of the present invention are:

1. It can actively detect the derailment of large-scale road maintenance vehicles, and make timely remedies to avoid losses;

2. Increase the temperature compensation coefficient to improve the sensitivity and accuracy of the ultrasonic distance sensor;

3. The ultrasonic frequency used in the present invention is increased, and the ultrasonic frequency is 250KHz, so that the ultrasonic wave length is about 5 times shorter than usual, which greatly improves the penetration ability of the ultrasonic wave and the anti-interference ability to the surrounding environment, avoiding the Influenced by air humidity, etc.

4. Using the anti-environmental interference signal method based on the automatic setting of the threshold, the processing module only receives the ultrasonic echo and then outputs the useful voltage signal. The frequency of the useful voltage signal processed by the processing module is between 200-300KHz, and the amplitude is between 2.5-3.3 Between v, the signal outside the range is used as the environmental interference signal to remove the superimposed interference signal in the environment, reduce the aftermath and crosstalk direct wave interference caused by the transmitting part, and reduce the false alarm rate and false alarm rate.

Description of drawings

Fig. 1 is the structural block diagram of the sensor of the embodiment of the present invention

Figure 2 is a schematic diagram of the state before the wheel derailment

Figure 3 is a schematic diagram of the state of the wheel after derailment

Figure 4 is a flowchart of the processor work

Figure 5 is a schematic diagram of ultrasonic echo frequency and amplitude threshold setting

Detailed ways

As shown in Figure 1, the embodiment of the present invention includes:

The ultrasonic distance sensor set on the bottom of the large road maintenance vehicle and pointing to the rail surface,

A processor for receiving and processing the distance value sent by the ultrasonic distance sensor;

The ultrasonic distance sensor is an ultrasonic distance sensor with a temperature compensation function, and the ultrasonic frequency emitted by the ultrasonic distance sensor is 250KHz.

The processor selects from the following actions:

When the current distance value sent by the ultrasonic distance sensor is greater than or equal to the set value, an alarm signal is sent;

or,

When the current distance value sent by the ultrasonic distance sensor is less than the set value, process the next distance value sent by the ultrasonic distance sensor.

In this embodiment, the ultrasonic distance sensor includes an ultrasonic probe, a temperature sensor, a pulse width modulation output module PWM (controlling the ultrasonic frequency of the ultrasonic sensor), a threshold value setting module, and a timer (sending ultrasonic waves to the transmitting end of the ultrasonic sensor until the echo reaches the ultrasonic wave) sensor receiving end for timing), temperature compensation module. Among them, the pulse width modulation output module, the threshold value setting module, the timer and the temperature compensation module are all integrated in the 32-bit DSP chip TMS320F2812. The pulse width modulation output module generates 250KHz pulses to drive the ultrasonic sensor to generate ultrasonic waves with a frequency of 250KHz. The threshold value setting module sets the frequency of the useful voltage signal between 200-300KHz and the amplitude between 2.5-3.3v.

The operating frequency of TMS320F2812 is 120MHz, and the timing accuracy of the timer is:

$\mathrm{<span\; class="notranslate">\; \&mu;</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 120</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; 10</span>}}^{\mathrm{<span\; class="notranslate">\; 6</span>}}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 8.3</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; 10</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 9</span>}}\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 8.3</span>}\mathrm{<span\; class="notranslate">\; ns</span>}$

The temperature sensor adopts the LM92 temperature sensor to detect the ambient temperature, and transmits the detected ambient temperature to the DSP chip TMS320F2812 to compensate the propagation speed of the ultrasonic wave at different ambient temperatures. The temperature measurement resolution of the LM92 temperature sensor is 0.0625°C, which can well compensate the propagation speed of ultrasonic waves at different temperatures.

Figures 2 and 3 are schematic diagrams before and after the derailment of the wheel. Normally, the distance between the bottom 1 of the large-scale road maintenance vehicle where the ultrasonic probe 3 is located (this embodiment is at the same height as the center of the wheel) and the rail surface 2 is 300mm; The distance between the wheel inner rings 5 is 20 mm, and the moment the wheel derails, the distance between the center of the wheel circle and the rail surface is 320 mm. Therefore, the processor setting value of this embodiment is 320 mm.

The time from the sending end of the ultrasonic probe to the time when the echo reaches the receiving end of the ultrasonic sensor is t, then the distance between the center of the wheel circle and the rail surface is s=ct/2, and c is the ultrasonic wave velocity.

Since the ultrasonic wave speed c will change with the influence of the ambient temperature, the temperature coefficient is increased to compensate for c. The relationship between the ultrasonic wave speed c and the real-time ambient temperature T is: c=c ₀ +0.607T, c ₀ is the propagation speed of ultrasonic wave in the air medium at normal temperature, and c ₀ =340m/s.

Therefore, the distance from the wheel center to the rail surface:

s=ct/2=(c ₀ +0.607T)t/2 (1)

Where c ₀ is known, it is only necessary to measure the real-time ambient temperature T and the time t from when the ultrasonic sensor emits the ultrasonic wave to when the echo reaches the ultrasonic sensor receiving end.

As shown in Figure 4, the set value of the processor is 320mm, and the processor compares the set value with the distance signal s sent by the calculation module. When s≥320mm, it means that the large road maintenance vehicle has derailed or is about to derail. The sensor sends an alarm signal (such as sound signal, display signal, etc.) or/and a stop signal; when s<320mm, it means that the large road maintenance vehicle is safe, and the processor processes the next distance value signal sent by the ultrasonic distance sensor.

As shown in FIG. 5 , the ultrasonic frequency of this embodiment is 250KHz, and the amplitude of the waveform after amplification is 3.3v. Therefore, set the receiving frequency and amplitude thresholds to 250Khz and 3v. When the ultrasonic frequency is 200KHz-300KHz and the amplitude is 2.5v-3.3v, it is a useful signal, that is, the ultrasonic probe outputs a voltage to the processing module after receiving the ultrasonic echo. Signal, the TMS320F2812 processing module processes the voltage signal with a frequency between 200-300KHz and an amplitude between 2.5-3.3v. The signals outside the range are environmental interference signals to remove the superimposed interference signals in the environment, reduce the aftermath and crosstalk direct wave interference caused by the transmitting part, and have the characteristics of reducing false alarm rate and false alarm rate.

Claims (4)

1. derailing detector for large road maintenance vehicle, it is characterized in that: it comprises:

Be arranged on large-scale road maintenance operation car bottom and point to the rail rail level the ultrasonic distance sensor,

Be used to receive distance value that the ultrasonic distance sensor sends and the treater of handling;

Described treater is selected following action:

The current distance value of sending when the ultrasonic distance sensor is sent alerting signal during more than or equal to setting value;

Or,

The current distance value of sending when the ultrasonic distance sensor is handled the next distance value that the ultrasonic distance sensor sends during less than setting value.

2. derailing detector for large road maintenance vehicle as claimed in claim 1 is characterized in that: described ultrasonic distance sensor is the ultrasonic distance sensor with temperature compensation function.

3. derailing detector for large road maintenance vehicle as claimed in claim 1 is characterized in that: the ultrasonic frequency that described ultrasonic distance sensor sends is 250KHz.

4. derailing detector for large road maintenance vehicle as claimed in claim 1, it is characterized in that: described ultrasonic distance sensor comprises ultrasonic probe, processing module, ultrasonic probe receives behind the ultrasonic echo to the processing module output voltage signal, processing module is handled the frequency of voltage signal between 200-300KHz, and amplitude is between 2.5-3.3v.

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