Zpracoval: Martin Bílek Pracoviště: Katedra textilních a jednoúčelových strojů TUL

Zpracoval: Martin Bílek Pracoviště: Katedra textilních a jednoúčelových strojů TUL

In-TECH 2, označuje společný projekt Technické univerzity v Liberci a jejích partnerů - Škoda Auto a.s. a Denso Manufacturing Czech s.r.o. Cílem projektu, který je v rámci Operačního programu Vzdělávání pro konkurenceschopnost (OP VK) financován prostřednictvím MŠMT z Evropského sociálního fondu (ESF) a ze státního rozpočtu ČR, je inovace studijního programu ve smyslu progresivních metod řízení inovačního procesu se zaměřením na rozvoj tvůrčího potenciálu studentů. Tento projekt je nutné realizovat zejména proto, že na trhu dochází ke zrychlování inovačního cyklu a zkvalitnění jeho výstupů. ČR nemůže na tyto změny reagovat bez osvojení nejnovějších inženýrských metod v oblasti inovativního a kreativního konstrukčního řešení strojírenských výrobků. Majoritní cílovou skupinou jsou studenti oborů Inovační inženýrství a Konstrukce strojů a zařízení. Cíle budou dosaženy inovací VŠ přednášek a seminářů, vytvořením nových učebních pomůcek a realizací studentských projektů podporovaných experty z partnerských průmyslových podniků. Délka projektu: 1.6.2009 31.5. 2012

Employment of high-speed camera in obtaining courses of cinematic quantities The laboratory measuring is focused on analysis of the movement of a component, seated with a necessary designing play, during the operating cycle. The movement of the component will be monitored by means of a high-speed recording camera OLYMPUS i-speed II, and the obtained records will be verified on the basis of picking-up the movement by means of a ultra-light acceleration sensor. The evaluation of the video record will be realised by means of the software i- SPEED. 1. Introduction The heald forms a part of the heald shaft frame on the weaving loom, and it provides for the coupling between its rods and the warp. Owing to the character of the structure and to the loading, the heald must be fitted in the frame with a necessary designing play; otherwise, it would be exposed to high stress, resulting in its destruction. However, it stands to reason that the said designing play is an important source of impacts during the weaving process. Owing to very low weight of healds (the weight of a heald ranges in the order of grams), it is not possible to effect the measuring by regular contact methods. One of the possibilities how to realise the said measuring is a contactless record by means of a high-speed camera. For generating the movement of heald during the weaving cycle, there is employed a testing appliance with an approximately sinusoidal course of the lift function. For recording purposes, a high-speed camera Olympus i-speed 2 has been used. The high-speed camera system i-speed 2 is able to record events that occur extremely fast. The video records of fast courses and processes are recorded digitally in the memory of the system, and they can be written on a Compact Flash card or downloaded into a notebook or PC by means of an Ethernet connection. Now, the video can be run at lower velocities, which permits its analysis shot after shot. Consequently, the user can review the event in detail, and identify quickly the sources of faults or defects. The software made to measure of user's requirements allows him an analysis and optimum processing of the shots. The system i-speed2 allows recording at the speed from 60 to 33 000 shots per second (up to 1 sec. /shot in the regime of "time short cut"), facilitating a fast and simple identification of processes. The high-speed camera will be used for recording real movement of the heald during the lift of the heald shaft. Nonetheless, the record made in this way does not permit to establish the velocity and the acceleration of the component accurately. The said measuring allows comparing various operating states of the system (e. g. the moment of the drop of the heald upon supporting wire) and an analyzing its behaviour with respect to operating velocity of the weaving loom. For the purpose of comparison and evaluation of the effect of tensile forces of the warp upon dynamic behaviour of the heald, there is picked up the heald alone, and on the other hand, the heald with inserted warp at various operating velocities. These forces are obtained from strain gauge sensors of tensile force in

the warp. The testing appliance facilitates continuous setting of operating velocities by means of a frequency converter. In this case, the measuring is carried in the velocity range from 200 r. p.m. to 1 200 r. p.m. of the main shaft, which corresponds to a double of the operating frequency of the shedding motion, i. e. from 100 r. p.m. to 600 r. p.m. of the crank shaft of the testing appliance. The crucial moment of the realised analysis is the drop of the heald upon the supporting wire of the rod or its separation from it, producing an undesirable force impulse. The evaluation is carried out visually by observing the record of the high-speed camera, with its subsequent evaluation by means of special software, serving for analyses of the video record. The information of the magnitude of the force in the warp thread is of importance, too. 1- High-speed camera Olympus, 2- CDU unit, 3- light source ILP-1, 4- data acquisition unit MGC Fig. 1: Measuring of the heald movement by means of high-speed camera

2. Measuring procedure and conditions For measuring, two types of healds of different weight are employed. With the first heald of the pair, no warp thread is used for the comparison; therefore, its movement is determined by the rod of the heald shaft frame and by its own weight. With the other heald of the pair, there has been applied a warp thread with prescribed pre-tension in the position of aligned shafts. The measuring and recording apparatus is shown in the fig. 1. The figure shows the high-speed camera with required lighting and the sensor of tension in the warp thread. The obtained values of the tensile force are stored as analogue data with the video record of the high-speed camera directly, which guarantees an unequivocal identification of magnitude of the tensile force referring to individual recorded phases of movement of the heald. For lighting, there is employed the light source ILP-1. The ILP-1 is a high capacity source of light, providing use of maximum luminous output. In comparison with preceding generations of high capacity sources of light, its weight and dimensions have been reduced substantially. The lighting element of ILP-1 is a newly developed UHP discharge lamp 120W, generating light of the colour temperature of 5 600 degree Kelvin. In order to obtain sharp shots of the heald movement, the recording frequency is set to 1000 Hz (the recording frequency providing for maximum picture definition) and the shutter to 10x (fig. 2). On the control panel of the testing appliance, there is set up the value of velocity of the lift of heald shaft frames, in which the heald is fastened. The recording of the action in course is activated (fig. 3). Simultaneously with the video recording, the data of the external analogue signal are being loaded. Once the recording is over, it is necessary to choose a sequence of shots to be loaded on a portable medium (fig. 4). The chosen part of the record is loaded on a portable card. Fig. 2: Setting of the high-speed camera for recording

Fig. 3: Course of the record of video data Fig. 4: Choice of a sequence to be loaded on a memory card 3. Analysis of obtained data The analysis of the video record has been realised by means of the software I-SPEED 2 Advance (fig. 5). There has been effected the calibration of the distance in individual records. With the video sequence, there has been carried out an automatic analysis of the trajectories of two chosen points (fig. 6), establishing their absolute position in the video record. From these absolute positions there

has been calculated the relative distance of the points, subsequently performing its transformation to the chosen state. The results of this analysis have been relative displacements of the points during the movement of the heald. On the basis of results of this analysis there have been established the moments of transfer of the heald between the rods of the heald shaft frame (fig.7). Fig. 5: Basic environment of the software I-SPEED 2 Advance Fig. 6: Automatic analysis of the video by means of I-SPEED 2 Advance software

Fig. 7: Moment of transfer of the heald