This thesis report contains two papers. The first paper is a literature study on mechanisms, smart actuated materials and controllable joints. In this paper, several smart materials are identified and it is discussed how they can be embedded in different mechanisms. From this pap
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This thesis report contains two papers. The first paper is a literature study on mechanisms, smart actuated materials and controllable joints. In this paper, several smart materials are identified and it is discussed how they can be embedded in different mechanisms. From this paper, it is concluded that fast-response smart material twisting actuators do currently not exist. The second paper studies the design and development of such an actuator. The study presents a design and manufacturing methodology of a planer actuator that generates out-of-plane rotation. It first investigates different out-of-plane deformation modes and how they can be used to achieve the desired motion. Based on an analytical model on the shape morphing of piezoelectric macro fibre composites, a methodology is developed to generate out-of-plane twisting deformation. This concept is used to design a carbon black electrode pattern, which can be spray-deposited on a kapton substrate. This electrode is subsequently used to selectively actuate parts of a P(VDF-TrFE- CTFE) polymer layer. The selective stimulation of the layer results in the desired twisting deformation. This study demonstrates how flat designs can be laminated in a planar additive manufacturing process to induce complex 3D motion. The spray-deposition process was capable of manufacturing bimorph actuators with a 1.6mm resolution. The resulting actuators have a length of 41mm and a width of 10 to 20mm and a thickness of 120 to 139micron. The experiments are used to characterize the effect of the design parameters such as actuator width and thickness on the magnitude of the deformation. As theorized in the analytical model, the thinner more slender samples show the largest rotation which is measured to rotate up to 3.38 degrees. From the experiments it is also found that thinner samples show dielectric breakdown at much lower voltages, around 100V, compared to thicker samples from the same design that performed up to 480V. The study also investigates the quality of the deformation of the actuators, i.e. pure twisting or a combination of twisting and bending deformation. It is verified that uneven layers or asymmetric actuators show significant unimorph bending behaviour, with displacements up to 1.5mm while rotating 3.38 degrees. To the author's best knowledge, this study presents the first working prototypes of fast-response smart material twisting actuators.