scholarly journals Deformation model and experimental evaluation of a contractable and bendable wire-pulling mechanism with embedded soft tubes for a robotic tongue

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Nobutsuna Endo
Keyword(s):  
Degrees Of Freedom ◽  
Physical Models ◽  
Deformation Model ◽  
Soft Body ◽  
Piecewise Constant ◽  
Multiple Degrees Of Freedom ◽  
Human Tongue ◽  
Drive And Control ◽  
Deformation Tests ◽  
And Control

AbstractFew physical models of oral and laryngeal systems for human speech movement exist for computer or mechanical simulators. In particular, a robot tongue mechanism that fully reproduces the deformation motion of the human tongue is lacking. The human tongue is an aggregate of muscles that is devoid of a skeleton. It possesses only a small hyoid. A mechanism that can drive and control the deformation of a soft body, such as the human tongue, along multiple degrees of freedom has not been realized to date. To solve this problem, a wire-pulling mechanism with embedded soft tubes is proposed. Using this mechanism, a flexible tongue that can be deformed along multiple degrees of freedom without breaking the wire is achieved. A prototype planar mechanism with two degrees of freedom that is capable of contraction and bending was fabricated. A deformation model that assumes a piecewise constant curvature (PCC) was formulated. Deformation tests confirmed that the prototype is capable of contraction and bending movements that are consistent with those of the model. Variations in the error with respect to the hardness of the deformable part are discussed, and the limits of the deformation model based on the PCC assumption are presented.

Flexible Pneumatic Bending Actuator for a Robotic Tongue

2020 ◽  
Vol 32 (5) ◽  
pp. 894-902
Author(s):  
Nobutsuna Endo ◽  
◽  
Yuta Kizaki ◽  
Norihiro Kamamichi
Keyword(s):  
Control Method ◽  
Tensile Tests ◽  
Physical Models ◽  
Silicone Resin ◽  
Deformation Model ◽  
Soft Body ◽  
Human Tongue ◽  
Simultaneous Control ◽  
Bending Actuator ◽  
Computer Simulators

There are not many physical models of oral and laryngeal systems for human speech movement in both computer simulators and mechanical simulators. In particular, there is no robot tongue mechanism that completely reproduces the deformation motion of the human tongue. The human tongue is an aggregate of muscles devoid of a skeleton. It only possesses a small hyoid. The purpose of this study is to develop a flexible actuator without a rigid link, aiming at the development of a tongue mechanism for a mechanical speech robot. We propose a flexible pneumatic bending actuator using thin McKibben muscles and a soft body formed by a silicone resin. We have verified its mechanical characteristics and described a control method for displacement and curvature. The elasticity/compliance of the silicone resin forming the soft body of this actuator was quantified by tensile tests. The oscillation parameters were identified, and it is suggested that the dynamic model can be described by a spring-mass-damper system. Assuming an arc-shaped deformation model, a simultaneous control system for the arc length and curvature was constructed and its effectiveness was confirmed.

Using Time-Periodicity for Inducing Energy Transfer Between Vibration Modes

2013 ◽  
Author(s):  
Fadi Dohnal ◽  
Aleš Tondl
Keyword(s):  
Energy Transfer ◽  
Degrees Of Freedom ◽  
Vibrational Energy ◽  
Low Frequency ◽  
Vibration Modes ◽  
Present Contribution ◽  
Multiple Degrees Of Freedom ◽  
Time Periodicity ◽  
The Many ◽  
And Control

Introducing time-periodicity in system parameters may lead, in general, to a dangerous and well-known parametric resonance. In contrast to such a resonance, a properly tuned time-periodicity is capable of transferring energy between vibration modes. Time-periodicity in combination with system damping is capable of efficiently extracting vibrational energy from the system and of amplifying the existing damping affecting transient vibrations. Operating the system at such a specific time-periodicity, the system is tuned at a parametric anti-resonance. The basic principle of this concept has been studied theoretically and was proven experimentally. The physical interpretation of this concept was proposed in “Damping by Parametric Stiffness Excitation: Resonance and Anti-Resonance”, Journal of Vibration and Control, 2008, for a multiple degrees of freedom system. The present contribution highlights those findings on a multiple degrees of freedom system. It is illustrated that a parametric anti-resonance is connected to inducing an energy transfer between two of the many vibration modes of the underlying system with constant coefficients. The induced energy transfer can be utilized to transfer the vibration energy from low frequency to high frequency or vice versa or, in case of system damping, to a more efficient dissipation of vibrational energy. The achievable energy dissipation is most significant if an energy transfer is induced between a lightly damped mode and a strongly damped mode.

Experimental Observation on a Controllable Underwater Towed Vehicle With Vertical Airfoil Main Body

2015 ◽  
Author(s):  
Jiaming Wu ◽  
Jian Chen ◽  
Ying Xu ◽  
Xiaodong Jin ◽  
Lihua Lu ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Main Body ◽  
Control Mechanisms ◽  
Attitude Stability ◽  
Multiple Degrees Of Freedom ◽  
Structural Style ◽  
Alternative Type ◽  
And Control ◽  
Righting Moment ◽  
Ducted Propellers

An alternative type of controllable underwater towed vehicle is proposed. The vehicle is composed of horizontal fixed main wing, adjustable wing flap, and a vertical airfoil main body above which two torpedo-shaped buoyant cylinders are symmetrically fixed. The adjustable wing flap serves as an actuator for deflection of the horizontal fixed main wing to produce enough downward lifting force to the towed vehicle running at a required water depth. Principal function of the torpedo-shaped buoyant cylinders is to create a righting moment or a favorite roll damping for attitude stability of the vehicle during towing operation. Meanwhile two ducted propellers are installed at the sterns of the buoyant cylinders to provide an induced turning moment for the vertical airfoil main body, which in turn produce a driving force for the vehicle in lateral motion. Results of our laboratory experiments indicate that flexible attitude and trajectory manipulations to the vehicle in multiple degrees of freedom can be achieved with the structural style and control mechanisms of the proposed vehicle. The manipulations to the vehicle with the proposed control mechanisms are accomplished by a joint operation of controlling the rotational speeds and directions of the ducted propellers and/or adjusting the deflection of the wing flap. By means of the proposed structural style and control manner, difficulty in designing control system of the vehicle can be reduced greatly, and stronger self stability of the vehicle during its survey towing can be guaranteed.

scholarly journals On Differential Mechanisms for Underactuated, Lightweight, Adaptive Prosthetic Hands

2021 ◽  
Vol 15 ◽  
Author(s):  
Geng Gao ◽  
Mojtaba Shahmohammadi ◽  
Lucas Gerez ◽  
George Kontoudis ◽  
Minas Liarokapis
Keyword(s):  
Degrees Of Freedom ◽  
Experimental Validation ◽  
Minimal Set ◽  
Prosthetic Devices ◽  
Multiple Degrees Of Freedom ◽  
Prosthetic Hands ◽  
Promising Application ◽  
End Effectors ◽  
Critical Components ◽  
And Control

Over the last decade underactuated, adaptive robot grippers and hands have received an increased interest from the robotics research community. This class of robotic end-effectors can be used in many different fields and scenarios with a very promising application being the development of prosthetic devices. Their suitability for the development of such devices is attributed to the utilization of underactuation that provides increased functionality and dexterity with reduced weight, cost, and control complexity. The most critical components of underactuated, adaptive hands that allow them to perform a broad set of grasp poses are appropriate differential mechanisms that facilitate the actuation of multiple degrees of freedom using a single motor. In this work, we focus on the design, analysis, and experimental validation of a four output geared differential, a series elastic differential, and a whiffletree differential that can incorporate a series of manual and automated locking mechanisms. The locking mechanisms have been developed so as to enhance the control of the differential outputs, allowing for efficient grasp selection with a minimal set of actuators. The differential mechanisms are applied to prosthetic hands, comparing them and describing the benefits and the disadvantages of each.

Еlectric Drive and Control System of Flying saw of electricweld item

2015 ◽  
Vol 19 (95) ◽  
pp. 50-53
Author(s):  
Aleksej A. Kravcov ◽  
◽  
Leonid G. Limonov ◽  
Valerij V. Sinelnikov ◽  
Stanislav V. Potapov
Keyword(s):  
Control System ◽  
Drive And Control ◽  
And Control

Control of processing at multi-tool two-support setup

2020 ◽  
pp. 67-73
Author(s):  
N.D. YUsubov ◽  
G.M. Abbasova
Keyword(s):  
Degrees Of Freedom ◽  
Factor Model ◽  
Angular Displacement ◽  
Factor Models ◽  
Technological System ◽  
Displacement Control ◽  
Model Accuracy ◽  
Six Degrees Of Freedom ◽  
Angular Displacements ◽  
And Control

The accuracy of two-tool machining on automatic lathes is analyzed. Full-factor models of distortions and scattering fields of the performed dimensions, taking into account the flexibility of the technological system on six degrees of freedom, i. e. angular displacements in the technological system, were used in the research. Possibilities of design and control of two-tool adjustment are considered. Keywords turning processing, cutting mode, two-tool setup, full-factor model, accuracy, angular displacement, control, calculation [email protected]

scholarly journals Data-Driven Stability Assessment of Multilayer Long Short-Term Memory Networks

2021 ◽  
Vol 11 (4) ◽  
pp. 1829
Author(s):  
Davide Grande ◽  
Catherine A. Harris ◽  
Giles Thomas ◽  
Enrico Anderlini
Keyword(s):  
Neural Network ◽  
Network Architecture ◽  
Short Term Memory ◽  
Moving Average ◽  
Machine Learning Algorithms ◽  
Physical Models ◽  
Data Driven ◽  
The Stability ◽  
And Control ◽  
Nonlinear Autoregressive

Recurrent Neural Networks (RNNs) are increasingly being used for model identification, forecasting and control. When identifying physical models with unknown mathematical knowledge of the system, Nonlinear AutoRegressive models with eXogenous inputs (NARX) or Nonlinear AutoRegressive Moving-Average models with eXogenous inputs (NARMAX) methods are typically used. In the context of data-driven control, machine learning algorithms are proven to have comparable performances to advanced control techniques, but lack the properties of the traditional stability theory. This paper illustrates a method to prove a posteriori the stability of a generic neural network, showing its application to the state-of-the-art RNN architecture. The presented method relies on identifying the poles associated with the network designed starting from the input/output data. Providing a framework to guarantee the stability of any neural network architecture combined with the generalisability properties and applicability to different fields can significantly broaden their use in dynamic systems modelling and control.

scholarly journals Design, Fabrication, and Testing of a Novel 3D 3-Fingered Electrothermal Microgripper with Multiple Degrees of Freedom

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 444
Author(s):  
Guoning Si ◽  
Liangying Sun ◽  
Zhuo Zhang ◽  
Xuping Zhang
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Polyimide Film ◽  
Zebrafish Embryos ◽  
Multiple Degrees Of Freedom ◽  
Electrothermal Actuator ◽  
3D Space ◽  
Pick And Place

This paper presents the design, fabrication, and testing of a novel three-dimensional (3D) three-fingered electrothermal microgripper with multiple degrees of freedom (multi DOFs). Each finger of the microgripper is composed of a V-shaped electrothermal actuator providing one DOF, and a 3D U-shaped electrothermal actuator offering two DOFs in the plane perpendicular to the movement of the V-shaped actuator. As a result, each finger possesses 3D mobilities with three DOFs. Each beam of the actuators is heated externally with the polyimide film. The durability of the polyimide film is tested under different voltages. The static and dynamic properties of the finger are also tested. Experiments show that not only can the microgripper pick and place microobjects, such as micro balls and even highly deformable zebrafish embryos, but can also rotate them in 3D space.

scholarly journals The emerging technology of biohybrid micro-robots: a review

2021 ◽  
Author(s):  
Zening Lin ◽  
Tao Jiang ◽  
Jianzhong Shang
Keyword(s):  
Self Assembly ◽  
Degrees Of Freedom ◽  
High Energy ◽  
Living Cells ◽  
Multiple Degrees Of Freedom ◽  
The Past ◽  
Great Prevalence ◽  
Performance Decline ◽  
High Energy Efficiency ◽  
Living Tissues

Abstract In the past few decades, robotics research has witnessed an increasingly high interest in miniaturized, intelligent, and integrated robots. The imperative component of a robot is the actuator that determines its performance. Although traditional rigid drives such as motors and gas engines have shown great prevalence in most macroscale circumstances, the reduction of these drives to the millimeter or even lower scale results in a significant increase in manufacturing difficulty accompanied by a remarkable performance decline. Biohybrid robots driven by living cells can be a potential solution to overcome these drawbacks by benefiting from the intrinsic microscale self-assembly of living tissues and high energy efficiency, which, among other unprecedented properties, also feature flexibility, self-repair, and even multiple degrees of freedom. This paper systematically reviews the development of biohybrid robots. First, the development of biological flexible drivers is introduced while emphasizing on their advantages over traditional drivers. Second, up-to-date works regarding biohybrid robots are reviewed in detail from three aspects: biological driving sources, actuator materials, and structures with associated control methodologies. Finally, the potential future applications and major challenges of biohybrid robots are explored. Graphic abstract

scholarly journals Integrated structured light architectures

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Randy Lemons ◽  
Wei Liu ◽  
Josef C. Frisch ◽  
Alan Fry ◽  
Joseph Robinson ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Temporal Distribution ◽  
Multiple Degrees Of Freedom ◽  
Beam Combination ◽  
Angular Momenta ◽  
Field Control ◽  
Topological States ◽  
Spatio Temporal ◽  
Temporal Field ◽  
Structural Versatility

AbstractThe structural versatility of light underpins an outstanding collection of optical phenomena where both geometrical and topological states of light can dictate how matter will respond or display. Light possesses multiple degrees of freedom such as amplitude, and linear, spin angular, and orbital angular momenta, but the ability to adaptively engineer the spatio-temporal distribution of all these characteristics is primarily curtailed by technologies used to impose any desired structure to light. We demonstrate a laser architecture based on coherent beam combination offering integrated spatio-temporal field control and programmability, thereby presenting unique opportunities for generating light by design to exploit its topology.

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