Smart Flexible Microactuators utilizing Piezoelectric Film

2005 Fiscal Year Final Research Report Summary

• Project/Area Number: 15360137
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Intelligent mechanics/Mechanical systems
• Research Institution: OKAYAMA UNIVERSITY
• Principal Investigator: SUZUMORI Koichi Okayama University, Graduate School of Natural Science and Technology, Professor, 大学院・自然科学研究科, 教授 (00333451)
• Co-Investigator(Kenkyū-buntansha): KANDA Takefumi Okayama University, Graduate School of Natural Science and Technology, Lecturer, 大学院・自然科学研究科, 講師 (30346449)
• Project Period (FY): 2003 – 2005
• Keywords: soft actuator / piezoelectric material / piezoelectric polymer / FMA / displacement sensor / functional thin film / paste injection

Research Abstract

Soft actuators have been receiving increasing attention in research area of robotics and mechtoronics. This research aims at a realization of intelligent actuator system which has such a flexible structure. The Frexible Microactuator (FMA) used for this research as the soft actuator and functional paste material was used for a sensing of displacement. The paste type functional materials can be deposited on the surface of curved rubber material by using a paste injection system which is controlled by three degrees of freedom scanning system. Two types of sensor have been fabricated and evaluated.
The first type flexible displacement sensor was a displacement sensor which fabricated by depositing conductive paste onto rubber. The paste injection system was used for the deposition of conductive paste precisely for curved surface. The sensor showed enough capability, and servo control for soft actuator was realized. Although the sensor has high compliance and is expected to be used for soft actuator, the linearity was diminished under the high strain applied condition.
We have also realized a wave patterning of conductive paste which can improve linearity. There must be optimal pitch of wave pattern which realizes high linearity and S/N ratio. To estimate the effect of this optimization, the sensor which had optimized pattern was fabricated and evaluated. The sample showed high linearity and S/N ratio
The second type flexible displacement sensor was realized by using the piezoelectric polymer as a paste type functional material. Piezoelectric polymer : poly(vinylidene fluoride-trifluoroethylene) copolymer[P(VDF/TrFE)] was deposited on FMA to detect the displacement and tension. In addition, conductive ink was used for electrodes. These sensors were fabricated on the surface of rubber with the paste injection system.
Touch sensor on the curved surface on the tip of FMA was also realized by depositing PZT film. A hydrothermal method was used for the deposition process.