Optimization on driving method of moving body in narrow passage considering nonlinearity of shape memory alloy actuator

Yamano, Akio; Shintani, Atsuhiko; Ito, Tomohiro; Nakagawa, Chihiro

doi:10.1299/transjsme.2014dr0119

Cited by 2 publications

(2 citation statements)

References 15 publications

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“…. From data points * y obtained by experiment, Everett function is identified using the curve fitting by the tree-based Genetic Programming (Yamano, et al, 2014). The identified hysteretic characteristics are shown in Fig.…”

Section: Identified Resultsmentioning

confidence: 99%

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Phase control of oscillators for moving body in narrow passage

Yamano

Shintani

Ito

et al. 2015

Mechanical Engineering Journal

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A flexible biomimetic fish-like robot for use in a flow in narrow passage was developed. Downsizing of the moving body was achieved using shape memory alloy (SMA) actuators. However, overheating an SMA actuator causes phase-transition saturation, and may cause a decrease in the fin vibration amplitude. In order to avoid this problem, a new driving method that utilized a self-excited oscillator was introduced. This proposed method is suited for generating oscillation with keeping temperature in SMA constant by using self-sensing, and needs to adjust only one parameter. We confirmed the effectiveness of the proposed driving method against overheating based on experiments and numerical simulations. Simulation proved that this method can keep thrust force of the moving body constant. For the fish-like moving body, multiple actuators are needed to realize higher degree of freedom behavior, and the phases of these actuator outputs also are needed to be synchronized to generate fish-like behavior, i.e., traveling wave. On the other hand, in the proposed driving method, the actuator system simulates a self-excited vibration system. Therefore, it was necessary to design the coupled inputs for oscillators composed by actuators to synchronize the oscillator outputs. To achieve this, a phase model was obtained from an actuator model, which consists of a thermal conductivity model and hysteresis model using a phase reduction analysis. Coupled inputs for proposed connecting method were designed based on this phase model, and the relationship between the phase difference of the coupled actuators and the connection gains was examined. Finally, we realized phase control using this.

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Section: Identified Resultsmentioning

confidence: 99%

“…Thus, the dynamics of an SMA actuator consists of a linearized thermal conductivity model ) (s G heat and the hysteretic characteristics between the temperature and bending moment hysteresis f ( Fig. 5) (Yamano, et al, 2014). Figure 6 shows the procedure of identification for actuator model.…”

Section: Actuator Model For Moving Bodymentioning

confidence: 99%

Phase control of oscillators for moving body in narrow passage

Yamano

Shintani

Ito

et al. 2015

Mechanical Engineering Journal

Self Cite

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Suppression of reflected waves of an aquatic flexible plate to improve efficiency of an aquatic propulsion mechanism

Matsumura

Furuya

Matsueda

et al. 2015

Transactions of the JSME (In Japanese)

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This study deals with a generation method of undulatory motion of an aquatic flexible plate, to improve the efficiency of an aquatic propulsion mechanism by suppression of a reflection wave on a trailing edge. Firstly, non-reflection impedance of a flexible plate was derived by using a matrix-based wave approach, and then control forces for trailing edge of a plate was derived by the impedance. Secondly, obtained non-reflection impedance was translated into the relationship of the displacements between leading edge and trailing edge, to generate a pure traveling wave by three linear actuators. By the relationship, appropriate forced displacements of trailing edge are available by referring to driving signals. However, the method uses a wave number of an aquatic planar plate, which is dependent on added mass effect. To overcome this difficulty, an identification method of wave numbers with constant amplitude for various driving frequencies was introduced. Finally the method was applied to an experimental apparatus. Experimental results showed that a quasi-pure traveling wave was generated on an aquatic flexible plate by the method.

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Optimization on driving method of moving body in narrow passage considering nonlinearity of shape memory alloy actuator

Cited by 2 publications

References 15 publications

Phase control of oscillators for moving body in narrow passage

Phase control of oscillators for moving body in narrow passage

Suppression of reflected waves of an aquatic flexible plate to improve efficiency of an aquatic propulsion mechanism

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