Advanced Electroactive Polymer Actuators and Sensors for Aerospace Robotic Applications (NNX13AN15A)

Transcription

1 Nevada NASA EPSCoR and Space Grant Annual Meeting April 30, 2015 Advanced Electroactive Polymer Actuators and Sensors for Aerospace Robotic Applications (NNX13AN15A) Principal Investigator: Kwang J. Kim, PhD Southwest Gas Professor of Energy and Matter Active Materials and Smart Living Laboratory Dept. of Mechanical Engineering University of Nevada, Las Vegas (UNLV) Office: (702) / Cell: (775) Web: Youtube:

2 Project Purpose 2 The main goal of our proposed interdisciplinary research program, between the University of Nevada, Las Vegas (UNLV), University of Nevada, Reno (UNR) and Truckee Meadows Community College (TMCC), is to advance the development and understanding of electroactive polymer materials for sensing and actuating applications in emerging robotic and space vehicles and systems. The team Kwang Kim, Dong-Chan Lee, and Woosoon Yim of UNLV Yantao Shen of UNR Ted Flaggemeyer of TMCC

3 Fundamental mechanism: actuation (IPMC) 3 A Simplified Model Current flux: J E L12 p Solvent flux: Q L E K p 21 Under an electric field {video} At 0.5 Hz, ±3 V square-wave input + MRS Bulletin (2008, Kim et al.)

4 Some videos (early development 1090s-2000s) 4

5 NASA and EAPs 5 Illustration of the Mars fly (top left) and the Mars or Moon worm (bottom left) these systems can be envisioned as robotic tools in micro/partial gravity environments. For example, a robotic worm made out of IPMC actuator/sensor, may be able to collect useful data or execute some special tasks on the Moon or Mars. A photograph of astronaut during extravehicular activities doing vibration monitoring and controls (right) in this mission, the IPMC technology can be used to enhance astronaut s performance. Also, the enhanced control system embedded with IPMC technology may be able to provide the astronauts improvement while they execute a task. (Figure sources: K. Krishen, Space applications for ionic polymermetal composite sensors, actuators, and artificial muscles, ACTA ASTRONAUTICA, 2009, 64: p

6 Challenges/Technical Objectives 6 Advanced applications are challenged by factors that include complex material behavior, nonlinearities, low mechanical output force, and tradeoffs between weight and multifunctionality. This program focuses on overcoming these challenges through research, education, training, and dissemination. Technical objectives to achieve this goal are to: Develop novel materials processing and synthesis techniques for electroactive polymers; Develop and validate models for mechanoelectrical transduction and actuation behaviors of electroactive polymers; Develop precision control strategies to compensate for nonlinear behaviors and disturbances; and Demonstrate optimized and functional design of electroactive polymer-based sensors and actuators.

7 Task 1: Materials Synthesis/Processing, Characterization, and Understanding of IPMC : Nafion and Poly(vinyl alcohol-co-ethylene) Blends for IMPCs (Lee, Kim, and Yim) 7 Objectives Reduce the cost of Nafion by blending with polymer additives. Optimize the film fabrication condition using poly(vinyl alcohol-co-ethylene) (P(VA-co-E)) as a blending partner. Assess the maximum content of polymer additive to maintain the electromechanical properties of Nafion. This approach could further be used to modify the mechanical properties of Nafion. Nafion P(VA-co-E): Ethylene 27 mol%, contains both hydrophilic and hydrophobic constituents, similar to Nafion, which can induce intermolecular interactions necessary to produce miscible polymer blends.

8 Blend film fabrication via a solution casting: Nafion 117 (5 wt%) + P(VA-co-E)/DMSO (5 wt%) solution in a Teflon mold (2.5cm x 2.5cm x 0.5cm) 8 Nafion NP30 NP50 Vol% of P(VA-co-E) Casting Temp. ( o C) Thickness (mm) Nafion NP FT-IR spectra NP DSC thermograms Transmittance (%) 3,200-3,400 cm 1 O-H stretching P(VA-co-E) NP50 NP30 Nafion 2,924 cm 1 C-H stretching Exo Heat Flow (W / g) 43 o C 45 o C T g = 59 o C Nafion NP30 NP50 P(VA-co-E) 161 o C 165 o C 1,153 and 1,213 cm 1 CF 2 stretching Wavenumber (cm -1 ) The blend films (NP30 and NP50) showed characteristic stretching peaks of both P(VA-co-E) and Nafion. Endo T m = 165 o C Temperature ( o C) Decrease in T g, T m, and H f with the decreased content of P(VA-co-E) indicate the formation of miscible blends.

9 The electrode surface resistance of IPMCs after electroless plating. 9 Samples 1 st Primary plating (Ω/cm) 2 nd Primary plating (Ω/cm) 3 rd Primary plating (Ω/cm) Secondary plating (Ω/cm) Nafion NP NP The cross-sectional morphologies of IPMCs based on (a) Nafion, (b) NP30, and (c) NP50 and the EDX results of (d) Nafion, (e) NP30, and (f) NP50. The actuation performance of the prepared IPMC actuators: measured voltage, current, and displacement responses at ±3 V AC square-wave under (a) 0.5 Hz and (b) 1.0 Hz. Photographs of IPMC actuators based on (a) Nafion, (b) NP30, and (c) NP50 with/without applying voltage (±3 V, AC) under varied frequency (0.1, 0.5, and 1.0 Hz). NP30 showed the similar electromechanical responses as Nafion!

10 Task 2: Modeling, Robotic Control, and Systems-Level Integration New IPMC Driver and Simulation (Shen and Kim) 10 VCC R3 100Ω Q1 TIP31AG C3 100µF C5 1µF Input_Signal R2 10kΩ OPA547T 3 7 U1 6 R1 10kΩ C1 100pF D1 02DZ4.7 D2 02DZ4.7 R4 100Ω R10 1Ω R11 1Ω Q2 TIP32AG Key = Space S3 IPMC Model R6 51Ω R5 51Ω C2 10µF VCC OPA547T S U kΩ R8 R7 1kΩ S2 Key = Space R9 10Ω Key = Space Sample Resistor VDD C6 1µF C4 100µF The designed IPMC driver Simulation: input and output (Sine, Triangle, and Square)

11 IPMC Driver Performance Testing: Excellent Linearity 11 4-channel IPMC Driver Prototype Input-output relationship (without IPMC load) Input-output of the designed IPMC driver under three waveforms (sine, square, and triangle) Input-output relationship (with IPMC load)

12 IPMC Driver Dynamics: Wide Bandwidth & Flat Phase 12 Magnitude and phase characteristics on the IPMC driver in voltage mode Magnitude and phase characteristics on the IPMC driver in current mode

13 Robotic (Earthworm) Integration and etc 13

14 Physics Based Modeling 14 A journal paper entitled Physics-based modeling of mechano-electric transduction of tube-shaped ionic polymer metal composite, was recently published in Journal of Applied Physics (Vol. 117, , 2015; This paper reports our research results in a physics-based model that is proposed to simulate mechanoelectrical transduction of 3D shaped ionic polymer metal composites. The lead author Tyler Stalbaum is a PhD student in the Mechanical Engineering Department of UNLV. Cation concentration near fixed end at max bending input. Right: Anion concentration near fixed end at max bending input. Input is tip displacement at 1.5 mm amplitude, 1 Hz. Concentration in units [mol/m 3 ].

15 Student Activities 15 In March of 2015, a team of University of Nevada, Las Vegas (UNLV) students including Jameson Lee, Sara Trabia, Shelby Nelson, Tyler Stalbaum, and Qi Chen, participated in the 17th annual EAP(electroactive poylmers materials)-in- Action session at the SPIE Smart Structures/NDE 2015 conference ( organized by Dr. Yosi Bar-Cohen of NASA JPL). This EAP-in-Action brings international teams who demonstrate their work in electroactive polymers and/or artificial muscles ( This year s demonstration was from eight different countries. Live demonstration of UNLV s EAPs Left-to-right: Viljar Palmre, Jameson Lee, Sara Trabia, Shelby Nelson, Tyler Stalbaum, and Qi Chen

16 Thanks & Questions!! 16