A mobile Mathieu oscillator model for vibrational locomotion of a bristlebot

2021 ◽  
pp. 1-8
Author(s):  
Phanindra Tallapragada ◽  
Chandravamsi Gandra
Keyword(s):  
Phase Diagram ◽  
High Frequency ◽  
Internal Mass ◽  
Slip Mode ◽  
Periodic Forcing ◽  
Stick Slip ◽  
Terrestrial Locomotion ◽  
Pipe Line ◽  
Parametric Oscillations ◽  
Resonance Oscillations

Abstract Terrestrial locomotion that is produced by creating and exploiting frictional anisotropy is common amongst animals such as snakes, gastropods, limbless lizards. In this paper we present a model of a bristle bot that locomotes by generating frictional anisotropy due to the oscillatory motion of an internal mass and show that this is equivalent to a stick-slip Mathieu oscillator. Such vibrational robots have been available as toys and theoretical curiosities and have seen some applications such as the well known kilobot and in pipe line inspection, but much remains unknown about this type of terrestrial locomotion. In this paper, motivated by a toy model of a bristle bot made from a toothbrush, we derive a theoretical model for its dynamics and show that its dynamics can be classified into four modes of motion : purely stick (no locomotion), slip, stick-slip and hopping. In the stick mode, the dynamics of the system are those of a nonlinear Mathieu oscillator and large amplitude resonance oscillations lead to the slip mode of motion. The mode of motion depends on the amplitude and frequency of the periodic forcing. We compute a phase diagram that captures this behavior, that is reminiscent of the tongues of instability seen in a Mathieu oscillator. The broader result that emerges in this paper is that mobile limbless continuum or soft robots can exploit high frequency parametric oscillations to generate fast and efficient terrestrial motion.

scholarly journals Dynamics of a Vibration Driven Bristlebot

2019 ◽  
Author(s):  
Chandravamsi Gandra ◽  
Phanindra Tallapragada
Keyword(s):  
Medical Devices ◽  
High Frequency ◽  
Nonlinear Vibrations ◽  
Analytical Models ◽  
System Of Equations ◽  
Internal Mass ◽  
Stick Slip ◽  
Wide Range ◽  
Potential Applications ◽  
Swarming Behavior

Abstract Vibration driven robots such as the so called bristlebot and kilobot utilize periodic forced vibration of an internal mass to achieve directed locomotion. These robots are supported on an elastic element such as bristles or cilia and contain an internal mass that is driven to oscillate at a high frequency. Besides well known applications in investigating swarming behavior, such robots have potential applications in rescue operations in rubble, inspections of pipes and other inaccessible confined areas and in medical devices where conventional means of locomotion is ineffective. Bristlebot or its commercially available variants such as hexbugs are popular toy robots. Despite the apparent simplicity of these robots, their dynamic behavior is very complex. Vibration robots have attracted surprisingly few analytical models, those models that exist can only explain some regimes of locomotion. In this paper, a wide range of motion dynamics of a bristlebot is explored using a mathematical model which accounts for slip-stick motion of the bristles with the substrate. Analytical conditions for the system to exhibit a particular type of motion are formulated and the system of equations defining the motion are solved numerically using these conditions. The numerical simulations show transitions in the kinds of locomotion of a bristlebot as a function of the forcing frequency. These different kinds of locomotion include stick-slip and pure slip motions along with the important phenomenon of the reversal of the direction of motion of the robot. In certain ranges of frequencies, the robot can lose contact with the ground and ‘jump’. These different regimes of locomotion are a result of the nonlinear vibrations of the robot and the friction between the robot’s bristles and the ground. The results of this paper can potentially lead to more versatile vibration robots with predictable and controllable dynamics.

Study of a piezo-electric actuated vibratory micro-robot in stick-slip mode and investigating the design parameters

2017 ◽  
Vol 89 (3) ◽  
pp. 1927-1948 ◽  
Author(s):  
Hadi Jalili ◽  
Hassan Salarieh ◽  
Gholamreza Vossoughi
Keyword(s):  
Design Parameters ◽  
Slip Mode ◽  
Stick Slip ◽  
Micro Robot ◽  
Piezo Electric

Active Control Methods for Drag Reduction in Flow Over Bluff Bodies (Keynote)

2002 ◽  
Author(s):  
Haecheon Choi
Keyword(s):  
Circular Cylinder ◽  
Drag Reduction ◽  
Active Control ◽  
High Frequency ◽  
Free Stream ◽  
Free Stream Velocity ◽  
Stream Velocity ◽  
Control Methods ◽  
Periodic Forcing ◽  
Time Periodic

In this paper, we present two successful results from active controls of flows over a circular cylinder and a sphere for drag reduction. The Reynolds number range considered for the flow over a circular cylinder is 40∼3900 based on the free-stream velocity and cylinder diameter, whereas for the flow over a sphere it is 105 based on the free-stream velocity and sphere diameter. The successful active control methods are a distributed (spatially periodic) forcing and a high-frequency (time periodic) forcing. With these control methods, the mean drag and lift fluctuations decrease and vortical structures are significantly modified. For example, the time-periodic forcing with a high frequency (larger than 20 times the vortex shedding frequency) produces 50% drag reduction for the flow over a sphere at Re = 105. The distributed forcing applied to the flow over a circular cylinder results in a significant drag reduction at all the Reynolds numbers investigated.

scholarly journals Stick-slip and Torsional Friction Factors in Inclined Wellbores

2018 ◽  
Vol 148 ◽  
pp. 16002 ◽  
Author(s):  
Ulf Jakob F. Aarsnes ◽  
Roman J. Shor
Keyword(s):  
High Frequency ◽  
String Model ◽  
Drill String ◽  
Distributed Model ◽  
Dynamic Friction ◽  
Stick Slip ◽  
Rock Interaction ◽  
Interaction Field ◽  
Friction Factors ◽  
Start Ups

Stick slip is usually considered a phenomenon of bit-rock interaction, but is also often observed in the field with the bit off bottom. In this paper we present a distributed model of a drill string with an along-string Coulomb stiction to investigate the effect of borehole inclination and borehole friction on the incidence of stick-slip. This model is validated with high frequency surface and downhole data and then used to estimate static and dynamic friction. A derivation of the torsional drill string model is shown and includes the along-string Coulomb stiction of the borehole acting on the string and the ‘velocity weakening’ between static and dynamic friction. The relative effects of these two frictions is investigated and the resulting drillstring behavior is presented. To isolate the effect of the along-string friction from the bit-rock interaction, field data from rotational start-ups after a connection (with bit off bottom) is considered. This high frequency surface and downhole data is then used to validate the surface and downhole behavior predicted by the model. The model is shown to have a good match with the surface and downhole behavior of two deviated wellbores for depths ranging from 1500 to 3000 meters. In particular, the model replicates the amplitude and period of the oscillations, in both the topside torque and the downhole RPM, as caused by the along-string stick slip. It is further shown that by using the surface behavior of the drill-string during rotational startup, an estimate of the static and dynamic friction factors along the wellbore can be obtained, even during stick-slip oscillations, if axial tension in the drillstring is considered. This presents a possible method to estimate friction factors in the field when off-bottom stick slip is encountered, and points in the direction of avoiding stick slip through the design of an appropriate torsional start-up procedure without the need of an explicit friction test.

scholarly journals Near-Fault High-Frequency Ground Motion Generated by Stick-Slip Events

1992 ◽  
Vol 45 (3) ◽  
pp. 305-315 ◽  
Author(s):  
Naoyuki KATO ◽  
Kiyohiko YAMAMOTO ◽  
Hidekazu YAMAMOTO ◽  
Tomowo HIRASAWA
Keyword(s):  
Ground Motion ◽  
High Frequency ◽  
Stick Slip ◽  
Near Fault

scholarly journals Hysteresis Behavior in the Stick–Slip Mode at the Boundary Friction

2013 ◽  
Vol 56 (6) ◽  
pp. 1019-1026 ◽  
Author(s):  
I. A. Lyashenko ◽  
A. V. Khomenko ◽  
A. M. Zaskoka
Keyword(s):  
Boundary Friction ◽  
Slip Mode ◽  
Stick Slip ◽  
Hysteresis Behavior

scholarly journals Study of FRSN cells migration under the conditions of continuous low flow

2018 ◽  
pp. 144-147
Author(s):  
А.А. Московцев ◽  
Д.В. Колесов ◽  
А.Н. Мыльникова ◽  
А.А. Кубатиев
Keyword(s):  
Stem Cells ◽  
Shear Stress ◽  
Cell Migration ◽  
Fluid Flow ◽  
Flow Direction ◽  
The Body ◽  
Low Flow ◽  
Slip Mode ◽  
Stick Slip ◽  
Low Intensity

Поток жидкости оказывает значительное влияние на морфофункциональное состояние большинства клеток в организме. Это может проявляться в миграции клеток под действием сдвиговой деформации или градиента питательных веществ. Мезенхимные стволовые фибробластоподобные клетки FRSN были культивированы в условиях воздействия постоянного потока жидкости в микрофлюидном чипе. Проведены исследования миграции клеток на разных стадиях адгезии под действием потока в различных областях чипа. Обнаружены значительные перемещения клеток в режиме «stick-slip» вдоль направления потока. The fluid flow exerts a significant effect on most cells in the body. This effect can involve cell migration under the action of shear stress or nutrient gradient. FRSN mesenchymal stem cells were cultured under the action of a constant fluid flow of low intensity in a microfluidic chip. The study of cell migration at different stages of adhesion was performed under the action of flow in different areas of the chip. Significant cell movements in a stick-slip mode along the flow direction were observed.

Sign in / Sign up

Export Citation Format

Share Document