Study on working mechanism and control method of new magnetic suspension gripper

The mechanical torsion drive mode used in existing looms results in high energy consumption and low efficiency during the weft insertion process due to mechanical impact, making it unsuitable for the weaving requirements of high-speed and ultra-wide fabrics. Based on the "zero loss" concept of magnetic suspension, this article proposes a magnetic suspension non-contact coupling method for weft insertion. It introduces a new magnetic suspension gripper configuration and clamping drive device, increasing the weft insertion speed to 40.0 m/s and reducing energy consumption to 7.2% of that of mechanical drives. The article explains the fundamental working principle of magnetic suspension weft insertion, establishes a dynamic model of projectile weft insertion, and conducts a systematic magneto-mechanical analysis. To enhance weft insertion performance and mitigate adverse effects caused by hysteresis nonlinearity and external interference, a lag-lead correction control strategy is proposed. Using control performance indices as objectives, a Bode diagram is drawn within the parameter design space to optimize performance. Tests demonstrate that the lag-lead correction method increases the system phase margin to 81.2°, shortens the dynamic response time of the magnetic suspension gripper weft insertion to 0.001 s, and maintains weft insertion trajectory accuracy within ± 0.1 mm, effectively suppressing trajectory deviations caused by hysteresis nonlinearity. The research results have established a comprehensive theoretical framework and engineering implementation plan, providing an innovative technical pathway for the automation upgrade of textile machinery.