Viscous streaming-enhanced inertial particle transport

Fluidic devices operating at the micro- and milli-meter scales employ several fundamental tasks involving pumping, mixing, separation, sorting, storing and transport of different fluids (or) species. An attractive fluid mechanism that can be leveraged to fulfill these wide range of tasks is viscous streaming, a non-linear effect characteristic of the scales above. In this thesis, we first show that numerical simulations based on the Remeshed Vortex Method (RVM) can accurately and efficiently capture viscous streaming dynamics. We test this algorithm on a wide variety of settings while simultaneously exhibiting the resultant streaming flow--structures, demonstrating both streaming's capability of effecting flow control and our solver's robustness in capturing these structures. We then consider the problem of an idealized two-dimensional inertial particle transport and prove that transport can be augmented by sensibly utilizing the streaming mechanism. We then successfully perform a forward--design study to devise shapes capable of enhanced transport using this mechanism, capitalizing on the insights gained from our demonstrations above. We envison such transport applications in the emergent technology of miniature robots, capable of traversing our blood stream to deliver payloads of therapeutical drugs

'Sculpting' fluid flow

Simple harmonic oscillation of cylinders in a fluid additionally lead to low magnitude time-steady (over many oscillations) fluid flow structures due to a mechanism called viscous streaming. By using a robust and accurate computational technique, we perform the first simulations of streaming. Using collectives to sculpt the flow, we obtain checker-board structures (visualized by fluid streamlines - blue: clockwise rotating, orange: counter clockwise rotating structures) which we can use, for example, to trap and manipulate particles. We envision high-impact bio-medical applications such as localized drug delivery using this technology.Ope

Energy Shaping Control of a CyberOctopus Soft Arm

This paper entails application of the energy shaping methodology to control a flexible, elastic Cosserat rod model. Recent interest in such continuum models stems from applications in soft robotics, and from the growing recognition of the role of mechanics and embodiment in biological control strategies: octopuses are often regarded as iconic examples of this interplay. Here, the dynamics of the Cosserat rod, modeling a single octopus arm, are treated as a Hamiltonian system and the internal muscle actuators are modeled as distributed forces and couples. The proposed energy shaping control design procedure involves two steps: (1) a potential energy is designed such that its minimizer is the desired equilibrium configuration; (2) an energy shaping control law is implemented to reach the desired equilibrium. By interpreting the controlled Hamiltonian as a Lyapunov function, asymptotic stability of the equilibrium configuration is deduced. The energy shaping control law is shown to require only the deformations of the equilibrium configuration. A forward-backward algorithm is proposed to compute these deformations in an online iterative manner. The overall control design methodology is implemented and demonstrated in a dynamic simulation environment. Results of several bio-inspired numerical experiments involving the control of octopus arms are reported

Viscous streaming-enhanced inertial particle transport

Fluidic devices operating at the micro- and milli-meter scales employ several fundamental tasks involving pumping, mixing, separation, sorting, storing and transport of different fluids (or) species. An attractive fluid mechanism that can be leveraged to fulfill these wide range of tasks is viscous streaming, a non-linear effect characteristic of the scales above. In this thesis, we first show that numerical simulations based on the Remeshed Vortex Method (RVM) can accurately and efficiently capture viscous streaming dynamics. We test this algorithm on a wide variety of settings while simultaneously exhibiting the resultant streaming flow--structures, demonstrating both streaming's capability of effecting flow control and our solver's robustness in capturing these structures. We then consider the problem of an idealized two-dimensional inertial particle transport and prove that transport can be augmented by sensibly utilizing the streaming mechanism. We then successfully perform a forward--design study to devise shapes capable of enhanced transport using this mechanism, capitalizing on the insights gained from our demonstrations above. We envison such transport applications in the emergent technology of miniature robots, capable of traversing our blood stream to deliver payloads of therapeutical drugs.LimitedAuthor requested closed access (OA after 2yrs) in Vireo ETD syste

Friction modulation in limbless, three-dimensional gaits and heterogeneous terrains

Motivated by a possible convergence of terrestrial limbless locomotion strategies ultimately determined by interfacial effects, we show how both 3D gait alterations and locomotory adaptations to heterogeneous terrains can be understood through the lens of local friction modulation. Via an `everything-is-friction' modeling approach, compounded by 3D simulations, the emergence and disappearance of a range of locomotory behaviors observed in nature is systematically explained in relation to inhabited environments. Our approach also simplifies the treatment of terrain heterogeneity, whereby even solid obstacles may be seen as high friction regions, which we confirm against experiments of snakes `diffracting' while traversing rows of posts [1], similar to optical waves. We further this optic analogy by illustrating snake refraction, reflection and lens focusing. We use these insights to engineer surface friction patterns and demonstrate passive snake navigation in complex topographies. Overall, our study outlines a unified view that connects active and passive 3D mechanics with heterogeneous interfacial effects to explain a broad set of biological observations, and potentially inspire engineering design

ADAMS-MATLAB Co-Simulation of A Serial Manipulator

This paper presents the dynamic modelling and simulation of a now redundant robot, Mitsubishi RM-501, and proposes a general algorithm for experimental simulation in kinematics, dynamics and control analysis to any such robot. Through reverse engineering, a model as accurate as the real robot was developed in SolidWorks.The simulations of the same were performed in ADAMS (dynamicmodeling software offered by MSC Software Corp)along with MATLAB for motion studies and control dynamics. Finally, with a user-input path the accuracy and precision of the simulator was verified

ADAMS-MATLAB Co-Simulation of A Serial Manipulator

This paper presents the dynamic modelling and simulation of a now redundant robot, Mitsubishi RM-501, and proposes a general algorithm for experimental simulation in kinematics, dynamics and control analysis to any such robot. Through reverse engineering, a model as accurate as the real robot was developed in SolidWorks.The simulations of the same were performed in ADAMS (dynamicmodeling software offered by MSC Software Corp)along with MATLAB for motion studies and control dynamics. Finally, with a user-input path the accuracy and precision of the simulator was verified