In this paper, a performance criterion is proposed for the optimization of piezoelectric patch actuator locations on flexible plate structures based on maximizing the controllability grammian. This is followed by the determination of parameters required for actuator location optimization through Structuring Analysis in ANSYS Finite Element Analysis Package. Genetic Algorithm is then used to implement the optimization. Finally, with the actuators bonded on optimized locations, a filtered-x LMS-based multichannel adaptive control is applied to suppress vibration response of the plate. Numerical simulations are performed in suppressing tri-sinusoidal response at three points of the plates. The results show that the developed actuator placement optimization methodology is very effective in searching for the optimal actuator locations that minimize the energy requirement of vibration control. The control algorithm is also demonstrated to be efficient and robust in the smart structure vibration control.
Nature has evolved to shape morphing to adapt to complex environments while engaging with the surroundings. Inspired by this capability, robots are expected to be endowed with the ability to perform shape‐changing, thus interacting with complex environments. Herein, a soft origami actuator with variable effective length (VEL) is proposed to adapt to different objects. The actuator's VEL is realized by an origami structure and actuated by hybrid actuation of tendons and pneumatic pressure. The soft actuator yields motion combining both elongation and bending generated by the asymmetric Yorshimura origami structure. Then an adaptive gripper composed of four origami actuators with programmable effective length is fabricated and its effect on grasping performance is evaluated through both simulations and experiments. Results show that the gripper can grip objects of different shapes, weights, sizes, and textures. This research may shed light on a new soft gripper design using origami structure for the environment's self‐adaptability.
The realization of controllable wrinkle pattern on a thin membrane is of great importance to micro/nanoengineering and aerospace engineering. Here, we report a straightforward method that achieves this outcome by introducing simple microstructures such as holes into the membrane. For a two-end clamped stretched membrane, the presence of holes redistributes stress field in the membrane, therefore monitors the buckling mode and wrinkle pattern of the membrane. Experiment, numerical simulation, and analytical model are provided to quantify this idea, and several wrinkle patterns are demonstrated. The results can provide insightful ideas to understand wrinkling phenomenon of microstructured membranes and to tailor wrinkle patterns used in various disciplines such as membrane manufacturing, cell differentiation, and film antenna in aerospace engineering.
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