Correction and control of lay-up force in automated fiber placement based on optimal pressure range

Automated Fiber Placement (AFP) has become a key technique for manufacturing lightweight, high-strength carbon fiber-reinforced polymer (CFRP) structures for aerospace applications. Precise control of process parameters, particularly lay-up force, is crucial for achieving high-quality placement and optimal mechanical properties. However, due to the complex interaction between the flexible roller and irregular mold surfaces, understanding pressure distribution during lay-up is challenging. This study develops a constitutive model for the roller and laminate and analyzes the roller-mold contact. Lay-up force is continuously adjusted to maintain the contact center pressure within the Optimal Pressure Range (OPR). To achieve real-time control, the roller cylinder’s dynamic characteristics were analyzed, and sliding mode control of the lay-up force was implemented by regulating input air pressure. Experimental results demonstrated the effectiveness of this approach, reducing pressure fluctuation residuals by 67.92%. The adjusted lay-up force maintained consistent pressure throughout the AFP process, significantly lowering defect risks compared to using a constant lay-up force.