Pony II Robot: Inertially Actuated Baton With Double-Action Pendulums

2014 ◽  
Author(s):  
Joe Zoghzoghy ◽  
Yilrdirim Hurmuzlu
Keyword(s):  
Numerical Simulations ◽  
Inertial Force ◽  
Inertial Forces ◽  
Low Friction ◽  
Experimental Prototype ◽  
Angular Velocities ◽  
Inertial Actuation ◽  
Friction Surfaces

In this paper, we present a robotic locomotor with inertia-based actuation. The goal of this system is to generate various gait modes of a baton, consisting of two masses connected with a massless rod. First, a model for a baton prototype called Pony II is presented. This model incorporates the double-action inertial actuation generated by two rotating pendulums, spinning at constant angular velocities in opposite directions. This system allows regulation of the inertial forces generated by the spinning masses. In addition, it provides control over the orientation of the resultant inertial force. Numerical simulations of four stable gaits are presented: dragging, tapping, galloping, and hopping. We also developed an experimental prototype, called Pony II, consisting of the double-action actuators. The robot successfully generates all the simulated gaits. In addition, we show that the robot is capable of generating progression on low friction surfaces.

scholarly journals An unrecognized inertial force induced by flow curvature in microfluidics

2021 ◽  
Vol 118 (29) ◽  
pp. e2103822118
Author(s):  
Siddhansh Agarwal ◽  
Fan Kiat Chan ◽  
Bhargav Rallabandi ◽  
Mattia Gazzola ◽  
Sascha Hilgenfeldt
Keyword(s):  
Entire Range ◽  
State Of The Art ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Inertial Force ◽  
Inertial Forces ◽  
Inertial Effects ◽  
Inviscid Flows ◽  
Flow Curvature ◽  
Complete Set

Modern inertial microfluidics routinely employs oscillatory flows around localized solid features or microbubbles for controlled, specific manipulation of particles, droplets, and cells. It is shown that theories of inertial effects that have been state of the art for decades miss major contributions and strongly underestimate forces on small suspended objects in a range of practically relevant conditions. An analytical approach is presented that derives a complete set of inertial forces and quantifies them in closed form as easy-to-use equations of motion, spanning the entire range from viscous to inviscid flows. The theory predicts additional attractive contributions toward oscillating boundaries, even for density-matched particles, a previously unexplained experimental observation. The accuracy of the theory is demonstrated against full-scale, three-dimensional direct numerical simulations throughout its range.

Effects of Gait Variations on Grip Force Coordination During Object Transport

2008 ◽  
Vol 100 (5) ◽  
pp. 2477-2485 ◽  
Author(s):  
Priska Gysin ◽  
Terry R. Kaminski ◽  
Chris J. Hass ◽  
Cécile E. Grobet ◽  
Andrew M. Gordon
Keyword(s):  
Grip Force ◽  
Gait Cycle ◽  
Time Window ◽  
Inertial Force ◽  
Step Length ◽  
Support Surface ◽  
Inertial Forces ◽  
Force Coupling ◽  
Temporal Coupling ◽  
Object Transport

In object transport during unimpeded locomotion, grip force is precisely timed and scaled to the regularly paced sinusoidal inertial force fluctuations. However, it is unknown whether this coupling is due to moment-to-moment predictions of upcoming inertial forces or a longer, generalized time estimate of regularly paced inertial forces generated during the normal gait cycle. Eight subjects transported a grip instrument during five walking conditions, four of which altered the gait cycle. The variations included changes in step length (taking a longer or shorter step) or stepping on and over a stable (predictable) or unstable (unpredictable support surface) obstacle within a series of baseline steps, which resulted in altered frequencies and magnitudes of the inertial forces exerted on the transported object. Except when stepping on the unstable obstacle, a tight temporal coupling between the grip and inertial forces was maintained across gait variations. Precision of this timing varied slightly within the time window for anticipatory grip force control possibly due to increased attention demands related to some of the step alterations. Furthermore, subjects anticipated variations in inertial force when the gait cycle was altered with increases or decreases in grip force, relative to the level of the inertial force peaks. Overall the maintenance of force coupling and scaling across predictable walking conditions suggests that the CNS is able to anticipate changes in inertial forces generated by gait variations and to efficiently predict the grip force needed to maintain object stability on a moment-to-moment basis.

Electromagnetic radiation and inertial forces

2019 ◽  
Vol 32 (4) ◽  
pp. 480-483
Author(s):  
Nasko Elektronov ◽  
Zhivko Kushev
Keyword(s):  
Electromagnetic Radiation ◽  
Doppler Effect ◽  
Inertial Force ◽  
Spectral Shift ◽  
Inertial Forces ◽  
Spectral Shifts ◽  
Nearby Stars ◽  
The Doppler Effect

The influence of the Coriolis inertial force generated by the orbital and spin motions of distant objects on the electromagnetic radiation energies during the exchange of photons between such objects has been considered. A red or blue spectral shift occurrence in a passive observation mode that is not associated with the Doppler effect or other known effects has also been shown. The relations found are used to calculate the spectral shifts for several nearby stars from our galaxy, as well as the spectral shifts of several galaxies. The results are close to the values currently observed.

Position and Weight Activated Passive Knee Mechanism

2015 ◽  
Author(s):  
Tyagi Ramakrishnan ◽  
Christina-Anne Lahiff ◽  
Asgard Kaleb Marroquin ◽  
Kyle B. Reed
Keyword(s):  
Human Gait ◽  
Low Friction ◽  
Human Knee ◽  
Prosthetic Knee ◽  
Normal Knee ◽  
Locking Mechanism ◽  
Angular Velocities ◽  
Normal Human ◽  
Prosthetic Knees ◽  
Simple Assembly

The human knee is a complex and robust system. It is the most important joint for human gait because of its immense load bearing ability. The loss of such an important joint often makes it difficult for a person to ambulate. Because of this and the resulting unnatural application of forces, many trans-femoral amputees develop an asymmetric gait that leads to future complications. Prosthetic knees are required to be well-designed to cope with all variabilities. There have been many prosthetic knee designs, some more complex than others. This paper describes the design and preliminary testing of a novel passive position and weight activated knee locking mechanism for use in lower limb prosthetics. This knee mechanism is designed to be a simple and economical alternative to existing knee mechanisms. The mechanism utilizes the dynamics of the user to lock the knee during stance and unlock during the swing phase. The presence of one moving component and a simple assembly makes this design a good base for customization. Results from testing the knee mechanism shows trends that are different from a normal human knee, which is to be expected. The prosthetic knee is designed to have low friction during swing of the shank and, hence, the flexion and extension angles and angular velocities are larger compared to a normal knee. The kinematics show a cyclic trend that is highly repeatable. Further refinement and testing can make this mechanism more efficient in mimicking a normal knee.

Sign in / Sign up

Export Citation Format

Share Document