The present invention refers to an installation for the automatic evaluation of the condition of the rolling band on wheels of moving trains, especially for the detection of cracks in said rolling band, in which ultrasonics are used to produce ultrasonic plots of the wheels when these pass over feelers installed on the track.
The prior art has already considered the measurement of certain railway vehicle wheel parameters. Hence, in EP-A-0 751 371, an installation and a process are described to measure parameters such as the flange thickness and height of a railway vehicle wheel, wheel diameter and the distance between inside faces of wheels mounted over the same axle, the measurement being made while the railway vehicle travels at its manoeuvre speed. Another example may be found in U.S. Pat. No. 4,866,642, where railway vehicle wheel diameters are calculated from data obtained by simultaneously producing two marker points on the surface of the rolling band and simultaneously detecting these marker points, as well as from data representing the known fixed position of the marker generators and probes. Likewise, in U.S. Pat. No. 4,798,964 a method and an apparatus are described to measure the quality of the rolling band of railway wheels without contact, by illuminating the circumferential surface of the wheel with a light or radiation source directing its radiation at least more or less in a radial direction over the wheel surface so as to form a luminous image of the profile or of the wheel rolling band.
Starting from the already known prior art, the invention has developed an installation for the automatic evaluation of the condition of the rolling band on wheels of moving trains, intended to be especially used for the detection of cracks in said rolling band, but may also be used to measure other railway vehicle wheel rolling parameters. This installation basically consists of a support structure, made of steel, formed by a rail beam for each railway line, replacing a section of the latter and over which the flange of the train wheels is made to pass, assuring the continuity between the rail beam and the railway line by means of a bolted joint; a guard-rail attached to each rail beam to ensure the guidance of the wheels while moving, being supported with their flange over the rail beam; feelers intended to come into contact with the wheels passing over them; feeler holders fitted on the rail beam, each one of them being provided with two guides and a swinging spring, such that the passage of the wheels over the feelers forces and assures the wheel-feeler contact; ultrasonics equipment to transmit programmable frequency and duration ultrasonic pulses towards the passing wheels and to generate and acquire ultrasonic plots corresponding to the wheels; a local processor to control the ultrasonic equipment and to digitally receive the signals generated by the ultrasonic plots; a computer connected to the local processor and responsible for giving the activation orders of the ultrasonics equipment, collecting, organizing and storing the measurement results and generating the pertinent reports; and an antenna connected to the computer and destined to identify the measured train compositions.
Conveniently, the feeler holders can be activated and deactivated in order to move vertically by means of two guides provided for such a purpose.
Preferably, the installation of the invention will include at least two feelers for each railway line, but it will also be possible to install four of said feelers for each line.
Each one of the mentioned feelers consists of a piezo-electric transducer to generate and receive superficial ultrasonic waves using a dry coupling means and including two inductive proximity detectors to indicate the presence of a wheel over the transducer. Preferably, the superficial waves generated and received by each transducer are of 1 MHz and the dry coupling means used in each transducer is a film of crude rubber.
According to the invention, the ultrasonics equipment is designed for the generation, acquisition and processing of ultrasonic signals in real time to perform non-destructive tests of materials and includes an analogical part and a digital part. Said analogical part comprises analogical treatment modules for the ultrasonic signals to be acquired, including programmable gain amplifiers and prefiltering, detection, logarithmic amplification and channel multiplexing stages, said programmable gain being 80 dB at 20 MHz and said logarithmic amplification being 100 dB.
Said digital part comprises a bus with segmented architecture and a set of dedicated processing modules of high effectiveness, said bus consisting of segments separated by bases over which the processing modules are housed.
According to the invention, the selection of the processor modules and their installation on the segmented architecture bus, permit the flexible definition of acquisition and processing chains of the xe2x80x9cpipelinexe2x80x9d type, with a high level of parallelism, adapting to the demands of each application, being possible to reach acquisition speeds of up to 80 Msamples/s with a maintained processing rate of 10 Msamples/s. Physical, processing modules exist with digital and mixed technology and each module has a set of programmable parameters and operation modes. Moreover, some fixed modules may modify their own architecture to execute different algorithms, by means of a software reconfiguration of its internal circuits.
According to the invention, the analogical part of the ultrasonics equipment is housed on an analogic base card serving as a support for the analogical amplification-filter modules across a series of slots with analogical channels in each one of them and containing, moreover, a stabilized voltage generation system, to supply the analogic modules, the input channel selection circuitry and an analogical module for envelope detection, these modules being governed by means of the control bus of said card. Said analogical part also includes an additional slot directly joined to the control bus, which permits to add a digital input-output card, which in the present case is for the detection of the wheels.
On the other hand, the digital part of the ultrasonic equipment is housed on a remote digital base card serving as a support for the digital and hybrid architecture processing modules, which are inserted in baseboards joined to the control bus of said card, each baseboard being joined to the following one by means of the segmented signal bus, through which receives the data processed by the previous module, delivering its results to the following module. Moreover, the output of each module is joined to a results memory. Said digital base card also contains the communications subsystem for the reception of orders and transmission of results, as well as a local processor controlling the entire digital base card and responsible for programming the modules, attending the communications and activating the capture and processing of signals.
Both the analogical base card and digital base card are connected to a power supply.
In a preferred embodiment of the invention, the analogical base card incorporates four slots with two analogical channels each one, and the remote digital base card incorporates four baseboards.
Likewise, according to the invention, the ultrasonics equipment includes a series of programmable pulse generators connected to the feelers and to the amplification modules. One of the aforementioned proximity sensor control modules is installed in the digital input-output slot of the analogical base card and a gain control module, an analogical/digital conversion module and a data reduction module are installed on the remote digital base card.
According to a preferred embodiment of the invention, four programmable pulse generators and two amplification modules are provided, which are installed on the analogical base card, each one of which incorporates two linear variable gain amplifiers.