A Planar Underactuated Compaction Mechanism with Self-Adaptability for Automated Fiber Placement Heads

Automated fiber placement (AFP) systems accommodate complex-shaped structures by pressing fibers against the non-planar surfaces of mandrels, in which compaction mechanisms are of crucial significance. A conventional compaction mechanism utilizes an independent actuator with compacting rollers to conform surfaces. Compared with these mechanisms, underactuated mechanisms can improve self-adjustability and functionality. This research introduces the concept design and the analysis of a planar underactuated compaction mechanism for automated fiber placement heads. Firstly, the requirements and design premise are determined. Then, a novel planar underactuated compaction mechanism with a bistable structure is constructed based on the metamorphic design theory. Secondly, the analytical models are established to give insight into the motion characteristics of the mechanism. Moreover, the example and simulation results are presented to verify the conceptual design. Furthermore, the standard deviation of the contact force of the planar underactuated compaction mechanism is much lower than that of a conventional compaction mechanism under equal conditions. Finally, the potential application of the underactuated mechanisms is discussed. Thus, this research shows that the designed compaction mechanism increases the adjustability, robustness, and high repeatability in positioning and can be used to simplify the motion planning for AFP systems when producing complex structures.