TENSION CONTROL IN FILAMENT WINDING USING CONSTANT FORCE MECHANISMS

The control of fiber tension has a significant impact on the geometrical and structural characteristics of the final product quality in filament winding. Controlling the tension and reducing disturbance in robotic filament winding is a great challenge due to the complex winding interface, sharp turning in trajectory, and fiber mechanics involved. Typical tension control strategies, e.g., rigid actuator or series elastic actuators, require costly electronic components or complex tension feedback control. Alternatively, constant force mechanisms (CFMs) may be incorporated into the filament winding system to control the tension force passively for a fixed displacement range. The objective of this study is to develop a large-stroke constant-force mechanism through design optimization and experimentally study the performance of force control with Proportional-Integral-Derivative (PID) and fuzzy controllers. A 2x2 Graph based path topology optimization was developed, and the resulting fixed-fixed beam was out-of-plumb with a slight out-of-straightness imperfection. In the experimental setup of the mock filament winding system, the fiber starts from a motorized feed mandrel, passes through pulleys with mounted tension/position sensors on a CFM array and finally reaches a motorized inlet mandrel. Both a PID controller and a Fuzzy controller were developed to evaluate and compare the performance of: (1) the CFM and rigid actuator systems, and (2) the controller types. The result shows that compared to the rigid actuator system, the CFM actuator system reduces peak tension overshoot by 34.17%similar to 45.42% and the tension coefficient of variation by 7.14%similar to 8.40%. In addition, the Fuzzy controller provides greater robustness, i.e., it allows more errors in position while continuing to maintain tension control performance. In conclusion, the CFM control strategy with PID or compatible Fuzzy control presents a great performance advantage over the existing tension control actuator strategies. The application of CFMs shows great potential in various force control in cable-based systems, e.g., vibration mitigation against strong wind in bridge cables, energy absorbing from earthquakes in buildings, elevators, etc.