@article{J21b,
title = {Finite Element Modeling of Soft Fluidic Actuators: Overview and Recent Developments},
author = {M. S. Xavier and A. J. Fleming and Y. K. Yong},
url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2021/02/J21b.pdf},
doi = {10.1002/aisy.202000187},
isbn = {2640-4567},
year = {2021},
date = {2021-02-01},
journal = {Advanced Intelligent Systems},
volume = {3},
number = {2},
pages = {2000187},
abstract = {Many soft robots are composed of soft fluidic actuators that are fabricated from silicone rubbers and use hydraulic or pneumatic actuation. The strong nonlinearities and complex geometries of soft actuators hinder the development of analytical models to describe their motion. Finite element modeling provides an effective solution to this issue and allows the user to predict performance and optimize soft actuator designs. Herein, the literature on a finite element analysis of soft actuators is reviewed. First, the required nonlinear elasticity concepts are introduced with a focus on the relevant models for soft robotics. In particular, the procedure for determining material constants for the hyperelastic models from material testing and curve fitting is explored. Then, a comprehensive review of constitutive model parameters for the most widely used silicone rubbers in the literature is provided. An overview of the procedure is provided for three commercially available software packages (Abaqus, Ansys, and COMSOL). The combination of modeling procedures, material properties, and design guidelines presented in this article can be used as a starting point for soft robotic actuator design.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{Ruppert2021,
title = {Active atomic force microscope cantilevers with integrated device layer piezoresistive sensors},
author = {M. G. Ruppert and A. J. Fleming and Y. K. Yong},
url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2021/01/J21a.pdf},
doi = {10.1016/j.sna.2020.112519},
year = {2021},
date = {2021-01-19},
journal = {Sensors & Actuators: A. Physical},
abstract = {Active atomic force microscope cantilevers with on-chip actuation and sensing provide several advantages over
passive cantilevers which rely on piezoacoustic base-excitation and optical beam deflection measurement. Active
microcantilevers exhibit a clean frequency response, provide a path-way to miniturization and parallelization and
avoid the need for optical alignment. However, active microcantilevers are presently limited by the feedthrough
between actuators and sensors, and by the cost associated with custom microfabrication. In this work, we propose
a hybrid cantilever design with integrated piezoelectric actuators and a piezoresistive sensor fabricated from the
silicon device layer without requiring an additional doping step. As a result, the design can be fabricated using a
commercial five-mask microelectromechanical systems fabrication process. The theoretical piezoresistor sensitivity
is compared with finite element simulations and experimental results obtained from a prototype device. The
proposed approach is demonstrated to be a promising alternative to conventional microcantilever actuation and
deflection sensing},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{J20h,
title = {Position and force sensing using strain gauges integrated into piezoelectric bender electrodes},
author = {R. Seethaler and S. Z. Mansour and M. G. Ruppert and A. J. Fleming},
url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2021/01/J20h-prepress-2.pdf},
doi = {10.1016/j.sna.2020.112416},
isbn = {0924-4247},
year = {2020},
date = {2020-12-30},
journal = {Sensors and Actuators A: Physical},
pages = {112416},
abstract = {This article derives design guidelines for integrating strain gauges into the electrodes of piezoelectric bending actuators. The proposed sensor can estimate the actuator tip displacement in response to an applied voltage and an external applied tip force. The actuator load force is also estimated with an accuracy of 8% full scale by approximating the actuator response with a linear model. The applications of this work include micro-grippers and pneumatic valves, which both require the measurement of deflection and load force. At present, this is achieved by external sensors. However, this work shows that these functions can be integrated into the actuator electrodes.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}