Papers by Victoria Webster-Wood
Bioinspiration & Biomimetics, 2016
In robotics, there is a need for small scale, compliant actuators for use in medical applications... more In robotics, there is a need for small scale, compliant actuators for use in medical applications or minimally invasive environmental monitoring. Biohybrid devices offer one solution to this need by using muscle cells to actuate compliant scaffolds. Such devices typically use biocompatible synthetic polymers as compliant scaffolds, which require additional processing steps to promote cellular alignment and attachment. Instead, electrocompacted and aligned collagen (ELAC) can be used as a completely organic scaffold, requiring no additional processing steps, with alignment being innately promoted by the topography. Locomotive living machines have been fabricated in this study using ELAC scaffolds. Devices have been produced using either primary cardiomyocytes or primary skeletal muscle cells isolated from chick embryos as actuators. When tested under the same conditions, skeletal muscle cell powered devices were approximately an order of magnitude faster, having a mean velocity of 77.6 ± 86.4 μm min(-1), compared to 9.34 ± 6.69 μm min(-1) for cardiomyocyte powered devices. In conclusion, completely organic living machines have been fabricated using electrocompacted collagen skeletons, and it was found that skeletal muscle powered devices were significantly faster than cardiomyocyte powered devices.
Lecture Notes in Computer Science, 2015
Lecture Notes in Computer Science, 2015
Lecture Notes in Computer Science, 2014
TCERA (Tunable Compliance Energy Return Actuator) is a robotic actuator inspired by properties an... more TCERA (Tunable Compliance Energy Return Actuator) is a robotic actuator inspired by properties and behavior of the human knee joint, in that it utilizes antagonistic contraction to vary torsional stiffness and joint angle. The actuator is an electrically activated artificial muscle which uses two constant air-mass pneumatic springs configured antagonistically about the knee joint. The positions of the actuator insertion points are controlled in order to change the effective torsional stiffness about the knee axis. Additionally, the rigid member to which the insertion points are attached is able to rotate in order to alter the static equilibrium of the knee system. Furthermore, the system has been simulated and an artificial neural network (ANN) has been trained to determine the control bar angle and attachment location required based on the desired angle, stiffness, and predicted torque state of the joint. Using this controller we have achieved actuator position and stiffness control both with and without load.
2013 IEEE/ASME International Conference on Advanced Intelligent Mechatronics, 2013
Tensegripede, the first prototype in a new series of modular, biologically inspired robots is pre... more Tensegripede, the first prototype in a new series of modular, biologically inspired robots is presented. The robot platform is used to test innovative mechanical and controller designs. The robot is comprised of rigid body segments joined via tensegrity joint structures. These joints provide compliance to the structure and can be actuated via drive cables to change relative segment orientation. The tensegrity connections allow the robot to actively steer and rear body segments to navigate over and around obstacles. Tensegripede is capable of climbing objects up to 0.75 times the wheel diameter without rearing and can rear to heights of 1.13 times the wheel diameter. Tensegripede employs a new biologically inspired motor controller using stable heteroclinic channels to control motor speed with a simple PWM-like scheme.
Adaptive Behavior, 2013
Cockroach shelter-seeking strategy may initially look like an undirected random search, but we sh... more Cockroach shelter-seeking strategy may initially look like an undirected random search, but we show that they are attracted to darkened shelters. They arrive at a shelter in about half the time control cockroaches take to reach the same location with no shelter present. We were able to identify six statistically significant trends from the behavior of 134 cockroaches in 1-min naïve walking trials with four different shelter configurations. By combining these trends into a model, we built a stochastic algorithm that significantly biases a simulated agent toward a target location. We call this model RAMBLER (Randomized Algorithm Mimicking Biased Lone Exploration in Roaches). RAMBLER could be adapted for a mobile robot equipped with an onboard camera and antenna-like contact sensors.
2012 IEEE International Conference on Robotics and Automation, 2012
Abstract Cockroach shelter-seeking strategy may look like an undirected random search, but we sho... more Abstract Cockroach shelter-seeking strategy may look like an undirected random search, but we show that they are attracted to darkened shelters, arriving at a shelter in about half the time it would otherwise take. We were able to identify four statistically significant trends from the behavior of 134 cockroaches in one-minute naïve walking trials with four different arena configurations. By combining these trends into a model, we arrive at an algorithm that significantly directs a simulated agent to a location. This algorithm was then adapted and ...
Acta Materialia, 2012
Experiments were conducted to characterize the influence of texture and impact velocity on the dy... more Experiments were conducted to characterize the influence of texture and impact velocity on the dynamic, high-strain, tensile extrusion of zirconium. Bullet-shaped samples were machined from a clock-rolled, highly textured Zr plate. Specimens in two orthogonal directions were tested: the extrusion direction aligned with either the in-plane (IP) rolling or the through-thickness (TT) direction of the plate. The post-extrusion microstructure and texture evolution were examined using electron backscatter diffraction microscopy and modeled using the viscoplastic self-consistent model. It was found that extrusion deformation was accomplished through a combination of twinning and slip with their relative activity greatly depending on the initial texture. In this regard, higher elongations in the IP samples as compared to the TT samples were observed at similar test velocities. This difference in ductility is discussed in terms of the material’s ability to accommodate plastic deformation. Due to the availability of a larger number of slip systems with relatively high Schmid factors in the IP samples under this configuration, plastic deformation by prismatic slip can be easily achieved, resulting in larger elongations. On the contrary, for TT samples, twinning preceded deformation by slip. This sequential deformation process, driven by the need to reorient the microstructure favorably to slip, led to diminished elongations to failure.
Dynamic Behavior of Materials, Volume 1, 2011
To create comprehensive models of mechanical deformation in Zirconium (Zr) it is important to obs... more To create comprehensive models of mechanical deformation in Zirconium (Zr) it is important to observe the effect of high strain on the material. The mechanical behavior and damage evolution in textured, high-purity zirconium (Zr) is influenced by strain rate, temperature, stress state, grain size, and texture. In particular, texture is known to influence the slip-twinning response of Zr, which directly affects the work hardening behavior at both quasi-static and dynamic strain rates. However, while microstructural and textural evolution of Zr in compression and to relatively low strains in tension has been studied, little is understood about the dynamic, high strain, tensile response of Zr. Here, the influence of texture on the dynamic, tensile, mechanical response of high-purity Zr is correlated with the evolution of the substructure. Experiments will be conducted using dynamic-tensile-extrusion process. A bullet-shaped sample has been impacted into a high-strength steel extrusion die and soft recovered in the Taylor Anvil Facility at Los Alamos National Laboratory. Finite element modeling that employs a continuum level constitutive description of Zr will be performed to provide insight into the dynamic extrusion process. Current experimental findings will be presented.
ICRA, 2012
Abstract Cockroach shelter-seeking strategy may look like an undirected random search, but we sho... more Abstract Cockroach shelter-seeking strategy may look like an undirected random search, but we show that they are attracted to darkened shelters, arriving at a shelter in about half the time it would otherwise take. We were able to identify four statistically significant trends from the behavior of 134 cockroaches in one-minute naïve walking trials with four different arena configurations. By combining these trends into a model, we arrive at an algorithm that significantly directs a simulated agent to a location. This algorithm was then adapted and ...
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Papers by Victoria Webster-Wood