Abstract:

Objective The load uniformity of braiding machine motor and the co-control of braiding, winding and pultrusion system seriously affect the stability of production systems, thus affecting the mechanical properties of formed parts. Therefore, in order to ensure the load uniformity of the motor and the system cooperative control among the weaving machine, the winding machine and the traction device is crucial to control the quality of the molding parts.

Method The dynamic uniform load control method based on the model predictive control (MPC) is proposed and applied to the braiding electromechanical unit, and the integrated mathematical model of the braiding-winding-pultrusion production system is established. The proportional synergistic deviation coupling control strategy is adopted to improve the collaborative working accuracy of the production system. The simulation and experiments were carried out to verify the proposed modeling and control strategy.

Results It was showed that the braiding machine motor speed can reach the stable state within 0.05 s under both two control strategies. The fluctuation of the motor speed under the dynamic uniform load control condition is within 2%, while the fluctuation of the motor speed under the parallel control condition is within 1%. Braiding machine motor torque showed that the output torque reaches the stable state within 0.05 s. For the same time, the maximum deviation of the output torque under the parallel control model is nearly 1 N·m, while the maximum deviation of the output torque of the dynamic uniform load control is about 0.2 N·m. Simulation results before model coupling shows the duration to the stable state for the braiding machine, winding machine and traction device. Since the three devices are independent of each other and have no direct physical connection, the times to steady state of these three devices are different. The motor speed of the braiding machine and the winding machine can be stabilized within 0.03 s, while the motor of the traction unit can be stabilized at about 0.08 s. Simulation results after model coupling shows the time to the stable state for the three devices under the proportional synergistic deviation coupling control model. The motor of the three devices reached the stable state within 0.08 s. The measured motor speed of the three devices under the proportional synergistic deviation coupling control condition showed good agreement with the simulation results. Braid angle comparison before and after control strategy optimization showed the braid angle fluctuates greatly before the optimization, while the weaving angle fluctuates little after the optimization.

Conclusion 1) The dynamic uniform load control method based on MPC effectively solves the problem of uneven load of the motor in the braiding process. In addition, the output torque is significantly reduced while the motor speed of the braiding machine is synchronized. 2) The proportional synergistic deviation coupling control strategy significantly improves the accuracy of the collaborative work of the production system. 3) The dynamic uniform load control method based on MPC and the proportional synergistic deviation coupling control strategy can effectively improve the stability of the braid angle, which will improve the mechanical properties of the forming parts. This research will provide support for industry production.

Key words: composite, pultrusion form, ring braiding machine, dynamic uniform load control, proportional synergistic deviation coupling