Microrobotics using composite materials: the micromechanical flying insect thorax

Abstract-In this paper, we present the design and fabrication of a centimeter-scale propulsion system for a robotic fish. The key to the design is selection of an appropriate actuator and a body frame that is simple and compact. SMA spring actuators are customized to provide the necessary work output for the microrobotic fish. The flexure joints, electrical wiring and attachment pads for SMA actuators are all embedded in a single layer of copper laminated polymer film, sandwiched between two layers of glass fiber. Instead of using individual actuators to rotate each joint, each actuator rotates all the joints to a certain mode shape and undulatory motion is created by a timed sequence of these mode shapes. Subcarangiform swimming mode of minnows has been emulated using five links and four actuators. The size of the four-joint propulsion system is 6mm wide, 40 mm long with the body frame thickness of 0.25mm.

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“…In the case where this buckling strength is insufficient, we can use alternative flexure designs such as an inversion flexure [19].…”

Section: Flexure Designmentioning

confidence: 99%

Design, fabrication and analysis of a body-caudal fin propulsion system for a microrobotic fish

Cho

Hawkes

Quinn

et al. 2008

2008 IEEE International Conference on Robotics and Automation

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“…Piezoelectric bending actuators have been utilized in many areas of robotics, such as to flap the wings of a micro air vehicle [1], to actuate control surfaces for indoor slow fliers [2], and even for motors for legged microrobots [3], [4]. However, in dynamic robots where piezoelectric actuators are the main source of actuation, the power output of these actuators is still unknown.…”

Section: Introductionmentioning

confidence: 99%

“…can obviously reduce power output of piezoelectric actuators, but to the authors' knowledge this has not been quantified at sufficient field (only up to 0.1V/µm in [10]). This work focuses on measuring the power output of the 10mm piezoelectric bending actuators discussed in [8], used to drive the wings of a 100 mg flapping wing air vehicle [1]. These 10mg actuators are composed of PZT-5H actuation layers with a carbon fiber elastic layer and glass fiber/carbon fiber extension as shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

Dynamometer power output measurements of piezoelectric actuators

Steltz

Fearing

2007

2007 IEEE/RSJ International Conference on Intelligent Robots and Systems

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Abstract-Piezoelectric bending actuators are an attractive option for driving microrobots due to their light weight, scalability, ease of integration and high bandwidth. However, the only existing energy or power output measurements for piezoelectric bending actuators have been extrapolated from DC values or unloaded AC values and are most likely overestimates. For microrobot applications such as flapping flight, accurate measures of power density are critical. In this work, to properly measure the energy output of a 10mg piezoelectric actuator, a custom dynamometer is designed and constructed to directly measure the power output at various frequencies and conditions. The dynamometer can simulate a pure resistive load at resonant frequencies from 1 to 100Hz. Due to low internal damping and fracture limits, actuators cannot be run in the matched condition at high fields (> 1 V/µm). Using the device, energy output per cycle at 1.6 V/µm was measured to be a maximum of 19.1 µJ/cycle (232 µm amplitude, 30Hz), giving a delivered energy density per cycle of 1.89J/kg. Internal actuator damping was measured at 1 V/µm to account for an energy loss of only 0.21µJ per cycle (232 µm amplitude, 30Hz).

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“…These devices were designed for optimal energy density as described in [25] for use in microrobotics projects, specifically for flapping wing micro air vehicles (MAV) [2], [3], [23].…”

Section: A Materials and Methodsmentioning

confidence: 99%

“…(12) The displacement is defined as a combination of (22) and (23) and is shown in appendix B. Substituting this into (12) yields the complete result for the effective mass of a tapered beam with a rigid extension.…”

Section: A Effective Cantilever Massmentioning

confidence: 99%

Nonlinear Performance Limits for High Energy Density Piezoelectric Bending Actuators

Wood

Steltz

Fearing

Proceedings of the 2005 IEEE International Conference on Robotics and Automation

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Abstract-To keep pace with recent advances in microrobotic structures demands actuator technologies which can deliver high power and precise motion. For electroactive material based actuators, high power typically implies either high field or high current drives which may lead to greater nonlinearities such as saturation, softening, and increased loss. Physical modeling of actuators is normally taken to be linear since the range of displacements, applied loads, and applied fields is typically small. If extrapolated to high drive conditions, these linear models significantly over predict the power which can be delivered. For actuators driving dynamic systems, a complete nonlinear model of the system will improve controllability and give more accurate estimations of power delivery capabilities. Here static nonlinearities and dynamic linear and nonlinear parameters are derived for high performance piezoelectric bending actuators.

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Microrobotics using composite materials: the micromechanical flying insect thorax

Cited by 65 publications

References 15 publications

Design, fabrication and analysis of a body-caudal fin propulsion system for a microrobotic fish

Design, fabrication and analysis of a body-caudal fin propulsion system for a microrobotic fish

Dynamometer power output measurements of piezoelectric actuators

Nonlinear Performance Limits for High Energy Density Piezoelectric Bending Actuators

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