scholarly journals Towards Dynamic Simulation Guided Optimal Design of Tumbling Microrobots

2019 ◽  
Author(s):  
Jiayin Xie ◽  
Chenghao Bi ◽  
David J. Cappelleri ◽  
Nilanjan Chakraborty
Keyword(s):  
Optimal Design ◽  
Dynamic Simulation ◽  
Point Contact ◽  
Small Scale ◽  
Trial And Error ◽  
Rigid Body Dynamic ◽  
Simulation Tools ◽  
Different Shapes ◽  
Body Dynamic ◽  
Two Bodies

Abstract Design of robots at the small scale is a trial-and-error based process, which is costly and time-consuming. There are no good dynamic simulation tools to predict the motion or performance of a microrobot as it moves against a substrate. At smaller length scales, the influence of adhesion and friction, which scales with surface area, becomes more pronounced. Thus, rigid body dynamic simulators, which implicitly assume that contact between two bodies can be modeled as point contact are not suitable. In this paper, we present techniques for simulating the motion of microrobots where there can be intermittent and non-point contact between the robot and the substrate. We use this simulator to study the motion of microrobots of different shapes and select shapes that are most promising for performing a given task.

scholarly journals Dynamic Simulation-Guided Design of Tumbling Magnetic Microrobots

2021 ◽  
pp. 1-26
Author(s):  
Jiayin Xie ◽  
Chenghao Bi ◽  
David J. Cappelleri ◽  
Nilanjan Chakraborty
Keyword(s):  
Dynamic Simulation ◽  
Point Contact ◽  
Small Scale ◽  
Incline Angle ◽  
Performance Simulation ◽  
Rigid Body Dynamic ◽  
Simulation Tools ◽  
Different Shapes ◽  
Magnetic Microrobots ◽  
Body Dynamic

Abstract Design of robots at the small scale is a trial-and-error based process, which is costly and time-consuming. There are few dynamic simulation tools available to accurately predict the motion or performance of untethered microrobots as they move over a substrate. At smaller length scales, the influence of adhesion and friction, which scales with surface area, becomes more pronounced. Thus, rigid body dynamic simulators, which implicitly assume that contact between two bodies can be modeled as point contact are not suitable. In this paper, we present techniques for simulating the motion of microrobots where there can be intermittent and non-point contact between the robot and the substrate. We use these techniques to study the motion of tumbling microrobots of different shapes and select shapes that are optimal for improving locomotion performance. Simulation results are verified using experimental data on linear velocity, maximum climbable incline angle, and microrobot trajectory. Microrobots with improved geometry were fabricated, but limitations in the fabrication process resulted in unexpected manufacturing errors and material/size scale adjustments. The developed simulation model is able to incorporate these limitations and emulate their effect on the microrobot's motion, reproducing the experimental behavior of the tumbling microrobots, further showcasing the effectiveness of having such a dynamic model.

scholarly journals Rigid Body Dynamic Simulation With Multiple Convex Contact Patches

2018 ◽  
Author(s):  
Jiayin Xie ◽  
Nilanjan Chakraborty
Keyword(s):  
Dynamic Simulation ◽  
Contact Point ◽  
Equations Of Motion ◽  
Point Contact ◽  
Rigid Bodies ◽  
The State ◽  
Contact Patch ◽  
Rigid Body Dynamic ◽  
Mixed Complementarity Problem ◽  
Intermittent Contact

We present a principled method for dynamic simulation of rigid bodies in intermittent contact with each other where the contact is assumed to be a non-convex contact patch that can be modeled as a union of convex patches. The prevalent assumption in simulating rigid bodies undergoing intermittent contact with each other is that the contact is a point contact. In recent work, we introduced an approach to simulate contacting rigid bodies with convex contact patches (line and surface contact). In this paper, for non-convex contact patches modeled as a union of convex patches, we formulate a discrete-time mixed complementarity problem where we solve the contact detection and integration of the equations of motion simultaneously. Thus, our method is a geometrically-implicit method and we prove that in our formulation, there is no artificial penetration between the contacting rigid bodies. We solve for the equivalent contact point (ECP) and contact impulse of each contact patch simultaneously along with the state, i.e., configuration and velocity of the objects. We provide empirical evidence to show that if the number of contact patches between two objects is less than or equal to three, the state evolution of the bodies is unique, although the contact impulses and ECP may not be unique. We also present simulation results showing that our method can seamlessly capture transition between different contact modes like non-convex patch to point (or line contact) and vice-versa during simulation.

A representation for comparing simulations and computing the purpose of geometric features

2001 ◽  
Vol 15 (2) ◽  
pp. 189-201
Author(s):  
THOMAS F. STAHOVICH ◽  
LEVENT BURAK KARA
Keyword(s):  
Computer Program ◽  
Dynamic Simulation ◽  
Directed Graphs ◽  
Kinematic Chain ◽  
The Other ◽  
Geometric Features ◽  
Causal Process ◽  
Rigid Body Dynamic ◽  
Causal Processes ◽  
Body Dynamic

We present a new representation that allows a rigid-body dynamic simulation to be described as a set of “causal-processes.” A causal-process is an interval of time during which both the behavior and the causes of the behavior remain qualitatively uniform. The representation consists of acyclic, directed graphs that are isomorphic to the flow of causality through the kinematic chain. Forces are the carriers of causality in this domain; thus they are central to the representation. We use this representation to compute the purposes of the geometric features on the parts of a device. To compute the purpose of a particular feature, we simulate the behavior of the device with and without the feature present. We then re-represent the two simulations as causal-processes and identify any causal-processes that exist in one simulation but not the other. Such processes are indicative of the feature's purpose. Because they are already causal descriptions of behavior, they can be directly translated into natural language descriptions of the feature's purpose. We have implemented our approach in a computer program called ExplainIT II.

Dynamic Simulation and Structure Optimization of the Folding Hoistable Mast Based on Adams

2014 ◽  
Vol 556-562 ◽  
pp. 1159-1164
Author(s):  
Qi Sheng Gao ◽  
Hai Tao Gu ◽  
Zhi Qiang Hu ◽  
Rong Zheng ◽  
Yang Lin
Keyword(s):  
Dynamic Stability ◽  
Dynamic Simulation ◽  
Parametric Optimization ◽  
Structure Optimization ◽  
Maximum Force ◽  
Rigid Body Dynamic ◽  
Simulation Results ◽  
In The Beginning ◽  
Body Dynamic ◽  
Structure Layout

In order to improve the safety and the dynamic stability of the hoistable mast, the method of parametric optimization was introduced and the dynamic model was established by the multi-rigid-body dynamic analysis soft of Adams in the beginning of the product design. Then, the dynamic simulation and the structure optimization were carried out. It was shown that the maximum force on the primary oil cylinder was reduced by 10%, the maximum force on the secondary oil cylinder was reduced by 8%, the structure layout of the mast was more reasonable and the dynamic stability were improved. Also, it was proved that the optimized structure of the hoistable mast was reasonable and feasible by simulation results.

Cylindrical Gears with Increased Contact Area – Proposal of Application in Watercrafts Power Transmission Systems

2015 ◽  
Vol 236 ◽  
pp. 26-30 ◽  
Author(s):  
Michał Batsch ◽  
Tadeusz Markowski ◽  
Wojciech Homik
Keyword(s):  
Power Transmission ◽  
Point Contact ◽  
Surface Strength ◽  
Hertz Theory ◽  
Cylindrical Gears ◽  
Position Errors ◽  
Power Transmission Systems ◽  
Involute Gears ◽  
Maximum Contact ◽  
Two Bodies

Paper presents the method for obtaining maximum contact pressure of Novikov gears. Described surface strength calculation method is based on Hertz theory of two bodies being in point contact. What’s more the influence of gear position errors on maximum contact stresses has been presented. Also the comparison of Hertz stresses for Novikov and involute gears has been made.

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