High-lift mechanism synthesis using an unconventional technique

Abstract

This research has two aims, a high-lift mechanism (HLM) synthesis using an unconventional technique and reliability-based design optimization (RBDO). The HLM is an important mechanism to control a lifting surface (flap) to generate addition lift during take-off and landing of an aircraft. The mechanism can work well with high precision, increasing performance of the flap. The HLM is one kind of four-bar mechanism, which is still used in commercial aircraft from Airbus and Boeing. The difficulty in design is to suppress the error of the actual motion and its targets. In previous studies, there are only two target points that included positions and angles of flaps during take-off and landing. This kind of the problem is called a motion generation problem. An inherent characteristic of this mechanism is that the design can meet all targets, but not for over nine points. The performance of the mechanism depends on the design technique and number of target points. Unconventional techniques for generating path and additional points as well as reliability-based design is proposed to increase HLM performance. The objective functions are to minimize the position and angle of the flaps, while design constraints include Grashof's law and working space. In a reliability-based design optimization problem, uncertainty due to link length tolerance is included in this problem to make it more reliable. Teaching-learning based optimization with a diversity archive (ATLBO-DA) is used as an optimizer in this study. The results reveal the proposed technique can be used to synthesize an HLM for greater reliability.