Biomimetics & Intelligent Microsystem Lab DATF Konkuk University 1 생체모사 (Biomimetics) Konkuk University - Artificial Muscle Actuators -

Biomimetics & Intelligent Microsystem Lab DATF Konkuk University 2 SYLABUS Contents Hours Introduction Background, definition, etc. (2), videos (4) 6 hours Learning from nature Runners (2), flyers (8), swimmers (6), others (2) 18 hours Artificial muscle actuators Piezoelectric materials, polymers, SMA, SMP, etc. 6 hours Potential applications2 hours Demonstration of biomimetics at KKU4 hours Term project preparation and presentation – Proposal (after 9 weeks) and result (after 14 weeks) 9 hours

Biomimetics & Intelligent Microsystem Lab DATF Konkuk University 3 Artificial Muscle Actuators Introduction Piezoelectric Actuators Unimorph Piezoelectric Actuator Polymer Actuators IPMC, Dielectric Elastomer, SMP Shape Memory Alloy

Biomimetics & Intelligent Microsystem Lab DATF Konkuk University 4 Introduction Biomimetic Actuation Rotorcraft Rotor Blade Control Aero Flapping Muscle Space Vibration Suppression MAV MAV Control Missile Fin Actuator Artificial Muscle Actuators

Biomimetics & Intelligent Microsystem Lab DATF Konkuk University 5 Actuation of real muscle Introduction (cont’d) Sarcomere Myofibril Myosin filament Actin filament RELAXATIONCONCENTRAION

Biomimetics & Intelligent Microsystem Lab DATF Konkuk University 6 Introduction (cont’d) Comparison of the properties of mammalian and artificial muscles

Biomimetics & Intelligent Microsystem Lab DATF Konkuk University 7 Introduction (cont’d) Comparative assessment of artificial muscle actuator technologies

Biomimetics & Intelligent Microsystem Lab DATF Konkuk University 8 Introduction (cont’d) EAP data vs. mass-specific power output of natural muscles

Biomimetics & Intelligent Microsystem Lab DATF Konkuk University 9 Introduction (cont’d)

Biomimetics & Intelligent Microsystem Lab DATF Konkuk University 10 Introduction (cont’d)

Biomimetics & Intelligent Microsystem Lab DATF Konkuk University Specific Energy (J / kg) Frequency (Hz) IPMC (Ionic Polymer- Metal Composite) Natural muscles Dielectric elastomer Piezoceramic Introduction (cont’d) Comparison of the properties (specific energy vs. Frequency)

Biomimetics & Intelligent Microsystem Lab DATF Konkuk University Blocked Stress (MPa) Maximum Actuation Strain IPMC Natural muscles Dielectric elastomer Piezo-polymer Piezo-ceramic Comparison of the properties (max. strain vs. blocked stress) Introduction (cont’d) Shape Memory Alloy

Biomimetics & Intelligent Microsystem Lab DATF Konkuk University 13 The word “piezoelectric” combines "piezo," which is derived from the Greek word for pressure, and "electric" from the Greek word for amber—static electricity generated by rubbing amber being the first known electric phenomenon. In a piezoelectric material, the application of a force or stress results in the development of a charge in the material. This is direct piezoelectric effect, found by Pierre and Paul-Jacques in Conversely, the application of a charge to the same material will result in a change in mechanical dimensions or strain. This phenomenon is known as electrostriction, or the reverse piezoelectric effect, where the strain is proportional to the square of the electric field. Several ceramic materials exhibit a piezoelectric effect. These include lead-zirconate-titanate (PZT), lead-titanate (PbTiO2), lead-zirconate (PbZrO3), and barium-titanate (BaTiO3). Strictly speaking, these ceramics are not actually piezoelectric but rather exhibit a polarized electrostrictive effect. Piezoelectric Actuator (cont’d) Piezoelectricity

Biomimetics & Intelligent Microsystem Lab DATF Konkuk University 14 A material must be formed as a single crystal to be truly piezoelectric. Ceramics have a multi-crystalline structure made up of large numbers of randomly orientated crystal grains. The random orientation of the grains results in a net cancellation of the piezoelectric effect. The ceramic must be polarized to align a majority of the individual grains' effects. Many polymers, ceramics, and molecules such as water are permanently polarized: some parts of the molecule are positively charged, while other parts of the molecule are negatively charged. When an electric field is applied to these materials, these polarized molecules will align themselves with the electric field, resulting in induced dipoles within the molecular or crystal structure of the material. Piezoelectric Actuator (cont’d) Piezoelectricity