Abstract:

Objective Accidental power loss during the warp knitting of a full-width fabric with weft lining for high-value materials of extracorporeal membrane oxygenation (ECMO) could lead to formation of defective cloth and the loss of high valued raw materials. This research deals with this problem to eliminate the fabric discontinuity so as to maintain highquality of such important fabrics.

Method Using the absolute coordinate mode of the servo motor and the slave axis electronic cam profile, the physical position information at the cam follower breakpoint was reverse-calculated. This position information was then used to identify the motion sequence intervals of the respective slave axes coordinating with the weft insertion mechanism. Subsequently, transition curves for each cam were designed using the key point data of the electronic cam. Finally, by utilizing cam table data streams, these transition curves were coupled with and switched to the original electronic cam curves, achieving accurate continuation of weaving from the breakpoint.

Results Experimental validation was carried out using a KSM2/1EL full-width warp knitting machine as the structural foundation, furnished with 7 servo-driven electronic weft insertion sub-shafts, each specifically dedicating to driving individual weft insertion devices. The machine was used for end uses such as the production of ECMO membrane wire materials. The contemporary full-width warp knitting system employed in this machine integrated the key ECMO membrane full-width weft insertion system breakpoint continuation control technology mentioned previously. Once the control system was powered on, the servo initialization module successively memorized the positions of the 7 electronic weft insertion servo master and slave axes in absolute coordinate mode. Each weft insertion axis was engineered with specific electronic weft insertion action phase intervals, and the positions of the master and slave axes at the breakpoint within the cam curve intervals were ascertained. This was accomplished by employing a weft insertion breakpoint recovery algorithm to sequentially restore on-site data. The KSM2/1EL full-width warp knitting machine was operated at a low speed for the experiment. The main shaft was halted at random positions, resulting in the cessation of the weft insertion mechanism with electrical drive. After the system was shut down until all energy was exhausted, it was restarted and the main shaft was gradually operated once again. Through the process of breakpoint continuation and multiple tests involving power interruptions at various weft insertion points, as well as extensive production sampling and application testing, it was verified that the motion system effectively resumes weaving oxygenation membrane fabric from any arbitrary position after power interruptions. The weft insertion mechanism smoothly coordinated with the movement to accomplish the insertion process. This verification confirmed that the motion system of the KSM2/1EL full-width warp knitting machine can reliably solve the problem of power-off reweaving of oxygenation membrane fabrics in various operating environments, demonstrating its capabilities in both experimental and production scenarios.

Conclusion The application of the absolute coordinate encoder mode of servo motor is proven to be the key to complete the physical information data recovery of the breakpoint continuation of the weft liner control system. The electronic computer-aided manufacturing(CAM) curve period of the weft laying system is the necessary information in the process of back pushing data, and the physical position information can be reversed when the power is interrupted by the application of the two. It is imperative to design the motion partition of the weft laying mechanism according to the motion time sequence requirements of the warp knitting spindle (chain) weft laying mechanism and the warp knitting slave axis (weft laying trolley, rake needle, side slip, etc.). The motion interval of the weft laying break point is reversely identified according to the physical position information of the main and slave axes at the break point. The data of the key point of the CAM is used to design the CAM transition curve of the algorithm. Finally, the transition curve and the original CAM curve are coupled and switched by the CAM table data flow application to realize the breakpoint continuous weaving of oxygenation membrane material.

Key words: full-width warp knitting machine, extracorporeal membrane oxygenation, membrane material, weft laying system, electronic cam, power-off reweaving