scholarly journals Design of a High-Speed Prosthetic Finger Driven by Peano-HASEL Actuators

2020 ◽  
Vol 7 ◽  
Author(s):  
Zachary Yoder ◽  
Nicholas Kellaris ◽  
Christina Chase-Markopoulou ◽  
Devon Ricken ◽  
Shane K. Mitchell ◽  
...  
Keyword(s):  
High Speed ◽  
Kinematic Model ◽  
Electrical Energy ◽  
Dc Motor ◽  
Self Healing ◽  
Force Output ◽  
Prosthetic Limbs ◽  
Neuromuscular Systems ◽  
Soft Actuators ◽  
Prosthetic Finger

Current designs of powered prosthetic limbs are limited by the nearly exclusive use of DC motor technology. Soft actuators promise new design freedom to create prosthetic limbs which more closely mimic intact neuromuscular systems and improve the capabilities of prosthetic users. This work evaluates the performance of a hydraulically amplified self-healing electrostatic (HASEL) soft actuator for use in a prosthetic hand. We compare a linearly-contracting HASEL actuator, termed a Peano-HASEL, to an existing actuator (DC motor) when driving a prosthetic finger like those utilized in multi-functional prosthetic hands. A kinematic model of the prosthetic finger is developed and validated, and is used to customize a prosthetic finger that is tuned to complement the force-strain characteristics of the Peano-HASEL actuators. An analytical model is used to inform the design of an improved Peano-HASEL actuator with the goal of increasing the fingertip pinch force of the prosthetic finger. When compared to a weight-matched DC motor actuator, the Peano-HASEL and custom finger is 10.6 times faster, has 11.1 times higher bandwidth, and consumes 8.7 times less electrical energy to grasp. It reaches 91% of the maximum range of motion of the original finger. However, the DC motor actuator produces 10 times the fingertip force at a relevant grip position. In this body of work, we present ways to further increase the force output of the Peano-HASEL driven prosthetic finger system, and discuss the significance of the unique properties of Peano-HASELs when applied to the field of upper-limb prosthetic design. This approach toward clinically-relevant actuator performance paired with a substantially different form-factor compared to DC motors presents new opportunities to advance the field of prosthetic limb design.

Hydraulically amplified self-healing electrostatic actuators with muscle-like performance

Science ◽  
2018 ◽  
Vol 359 (6371) ◽  
pp. 61-65 ◽  
Author(s):  
E. Acome ◽  
S. K. Mitchell ◽  
T. G. Morrissey ◽  
M. B. Emmett ◽  
C. Benjamin ◽  
...  
Keyword(s):  
High Speed ◽  
Dielectric Breakdown ◽  
Artificial Muscle ◽  
Robotic Arm ◽  
Soft Robotics ◽  
Self Healing ◽  
Electrostatic Actuators ◽  
Robotic Devices ◽  
Soft Actuators ◽  
Wide Potential

Existing soft actuators have persistent challenges that restrain the potential of soft robotics, highlighting a need for soft transducers that are powerful, high-speed, efficient, and robust. We describe a class of soft actuators, termed hydraulically amplified self-healing electrostatic (HASEL) actuators, which harness a mechanism that couples electrostatic and hydraulic forces to achieve a variety of actuation modes. We introduce prototypical designs of HASEL actuators and demonstrate their robust, muscle-like performance as well as their ability to repeatedly self-heal after dielectric breakdown—all using widely available materials and common fabrication techniques. A soft gripper handling delicate objects and a self-sensing artificial muscle powering a robotic arm illustrate the wide potential of HASEL actuators for next-generation soft robotic devices.

scholarly journals A Nonlinear Model for Online Identifying a High-Speed Bidirectional DC Motor

2020 ◽  
Vol 24 (5) ◽  
pp. 245-258
Author(s):  
Ayad Mahmood Kwad ◽  
Dirman Hanafi ◽  
Rosli Omar ◽  
Hisyam Abdul Rahman
Keyword(s):  
High Speed ◽  
Magnetic Energy ◽  
Weighted Least Squares ◽  
Dead Zone ◽  
Nonlinear Behavior ◽  
Electrical Energy ◽  
Dc Motor ◽  
Mechatronic Systems ◽  
Online Identification ◽  
Inherent Feature

The modeling system is a process to define the real physical system mathematically, and the input/output data are responsible for configuring the relation between them as a mathematical model. Most of the actual systems have nonlinear performance, and this nonlinear behavior is the inherent feature for those systems; Mechatronic systems are not an exception. Transforming the electrical energy to mechanical one or vice versa has not been done entirely. There are usually losses as heat, or due to reverse mechanical, electrical, or magnetic energy, takes irregular shapes, and they are concerned as the significant resource of that nonlinear behavior. The article introduces a nonlinear online Identification of a high-speed bidirectional DC motor with dead zone and Coulomb friction effect, which represent a primary nonlinear source, as well as viscosity forces. The Wiener block-oriented nonlinear system with neural networks are implemented to identify the nonlinear dynamic, mechatronic system. Online identification is adopted using the recursive weighted least squares(RWLS) method, which depends on the current and (to some extent) previous data. The identification fitness is found for various configurations with different polynomial orders, and the best model fitness is obtained about 98% according to normalized root mean square criterion for a third order polynomial.

scholarly journals Dynamics of electrohydraulic soft actuators

2020 ◽  
Vol 117 (28) ◽  
pp. 16207-16213 ◽  
Author(s):  
Philipp Rothemund ◽  
Sophie Kirkman ◽  
Christoph Keplinger
Keyword(s):  
Electric Fields ◽  
High Speed ◽  
Scaling Analysis ◽  
Self Healing ◽  
Electrostatic Actuator ◽  
Fundamental Physics ◽  
Soft Actuators ◽  
External Loads ◽  
Electrohydraulic Actuators ◽  
Inertial Regime

Nature has inspired the design of robots in which soft actuators enable tasks such as handling of fragile objects and adapting to unstructured environments. Those tasks are difficult for traditional robots, which predominantly consist of hard components. Electrohydraulic soft actuators are liquid-filled shells that deform upon the application of electric fields; they excel among soft actuators with muscle-like force outputs and actuation strains, and with actuation frequencies above 100 Hz. However, the fundamental physics that governs the dynamics of electrohydraulic soft actuators is unexplored. Here, we study the dynamics of electrohydraulic soft actuators using the Peano-HASEL (hydraulically amplified self-healing electrostatic) actuator as a model system. Using experiments and a scaling analysis, we discover two dynamic regimes: a regime in which viscous dissipation reduces the actuation speed and a regime governed by inertial effects in which high-speed actuation is possible. For each regime, we derive a timescale that describes the influence of geometry, materials system, and applied external loads on the actuation speed. We also derive a model to study the dynamic behavior of Peano-HASEL actuators in both regimes. Although this analysis focuses on the Peano-HASEL actuator, the presented results may readily be generalized to other electrohydraulic actuators. When designed to operate in the inertial regime, electrohydraulic actuators will enable bio-inspired robots with unprecedented speeds of motion.

scholarly journals Development and Evaluation of Fuel-less Power Generator

2019 ◽  
Vol 9 (1) ◽  
pp. 3559-3563
Keyword(s):  
High Speed ◽  
Power Plants ◽  
Energy Use ◽  
Political Action ◽  
Rapid Development ◽  
Electrical Energy ◽  
Dc Motor ◽  
Current Output ◽  
Power Generator ◽  
Alternative Power

The erratic power supply has been a growing cause for concern in developing countries. It becomes more challenging to supply adequate energy in countries with a high population due to the increased demand and this has led to load shedding and spreading in Nigeria. Also, emissions from power plants, impacts of hydroelectric development, and risks associated with nuclear energy use have been targets for political action due to the recent pursuit of sustainability development. Also, evidence of depletion of the protective ozone layer and its impact on the environment have urged the need for rapid development of alternative power generation method void of causing adverse environmental impact. This paper, therefore, discusses the design and evaluation of a self-starting fuel less power generator using DC motor as the prime mover to generate electrical energy from an alternator. The alternator armature shaft was coupled directly with DC motor powered by a rechargeable battery. The DC motor rotates the armature of the alternator in the field coil at high speed when activated from the starting switch, which results in alternating current output voltages of 220V.

scholarly journals Observation and analysis of diving beetle movements while swimming

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Debo Qi ◽  
Chengchun Zhang ◽  
Jingwei He ◽  
Yongli Yue ◽  
Jing Wang ◽  
...  
Keyword(s):  
Swimming Speed ◽  
High Speed ◽  
Kinematic Model ◽  
Movement Pattern ◽  
Unmanned Vehicles ◽  
Power Stroke ◽  
Cross Sectional ◽  
Motion Data ◽  
The Cross ◽  
Diving Beetle

AbstractThe fast swimming speed, flexible cornering, and high propulsion efficiency of diving beetles are primarily achieved by their two powerful hind legs. Unlike other aquatic organisms, such as turtle, jellyfish, fish and frog et al., the diving beetle could complete retreating motion without turning around, and the turning radius is small for this kind of propulsion mode. However, most bionic vehicles have not contained these advantages, the study about this propulsion method is useful for the design of bionic robots. In this paper, the swimming videos of the diving beetle, including forwarding, turning and retreating, were captured by two synchronized high-speed cameras, and were analyzed via SIMI Motion. The analysis results revealed that the swimming speed initially increased quickly to a maximum at 60% of the power stroke, and then decreased. During the power stroke, the diving beetle stretched its tibias and tarsi, the bristles on both sides of which were shaped like paddles, to maximize the cross-sectional areas against the water to achieve the maximum thrust. During the recovery stroke, the diving beetle rotated its tarsi and folded the bristles to minimize the cross-sectional areas to reduce the drag force. For one turning motion (turn right about 90 degrees), it takes only one motion cycle for the diving beetle to complete it. During the retreating motion, the average acceleration was close to 9.8 m/s2 in the first 25 ms. Finally, based on the diving beetle's hind-leg movement pattern, a kinematic model was constructed, and according to this model and the motion data of the joint angles, the motion trajectories of the hind legs were obtained by using MATLAB. Since the advantages of this propulsion method, it may become a new bionic propulsion method, and the motion data and kinematic model of the hind legs will be helpful in the design of bionic underwater unmanned vehicles.

A Mechanistic Force Model of the 5-Axis Milling Process

2000 ◽  
Author(s):  
Paul A. Clayton ◽  
Mohamed A. Elbestawi ◽  
Tahany El-Wardany ◽  
Dan Viens
Keyword(s):  
High Speed ◽  
Mechanistic Model ◽  
Back Propagation ◽  
High Speed Steel ◽  
Cutting Edge ◽  
Analytic Description ◽  
Force Model ◽  
Force Output ◽  
Five Axis ◽  
Milling Force Model

Abstract This paper presents a five-axis milling force model that can incorporate a variety of cutters and workpiece materials. The mechanistic model uses a discretized cutting edge to calculate an area of intersection which is multiplied by the specific cutting pressure to produce a force output along the primary cartesian coordinate system. By using an analytic description of the cutting edge with a non-specific cutter and workpiece intersection routine, a model was created that can describe a variety of cutting situations. Furthermore, a back propagation neural network is used to calibrate the model, providing robustness and scalability to the calibration process. Testing was performed on 1020 steel using various cutting parameters with a high speed steel two flute cutter and a tungsten carbide insert cutter. Furthermore, both linear cuts and a test die surface yielded good agreement between predicted and measured results.

scholarly journals Phase-transformation-induced lubrication of earthquake sliding

2017 ◽  
Vol 375 (2103) ◽  
pp. 20160008 ◽  
Author(s):  
Harry W. Green
Keyword(s):  
Phase Transformation ◽  
Dry Friction ◽  
High Speed ◽  
Frictional Resistance ◽  
Low Pressure ◽  
Self Healing ◽  
Strength Recovery ◽  
Endothermic Reactions ◽  
Shear Heating ◽  
Fast Motion

Frictional failure is not possible at depth in Earth, hence earthquakes deeper than 30–50 km cannot initiate by overcoming dry friction. Moreover, the frequency distribution of earthquakes with depth is bimodal, suggesting another change of mechanism at about 350 km. Here I suggest that the change at 30–50 km is from overcoming dry friction to reduction of effective stress by dehydration embrittlement and that the change at 350 km is due to desiccation of slabs and initiation by phase-transformation-induced faulting. High-speed friction experiments at low pressure indicate that exceeding dry friction provokes shear heating that leads to endothermic reactions and pronounced weakening. Higher-pressure studies show nanocrystalline gouge accompanying dehydration and the highest pressure experiments initiate by exothermic polymorphic phase transformation. Here I discuss the characteristic nanostructures of experiments on high-speed friction and high-pressure faulting and show that all simulated earthquake systems yield very weak transformation-induced lubrication, most commonly nanometric gouge or melt. I also show that phase-transformation-induced faulting of olivine to spinel can propagate into material previously transformed to spinel, apparently by triggering melting analogous to high-speed friction studies at low pressure. These experiments taken as a whole suggest that earthquakes at all depths slide at low frictional resistance by a self-healing pulse mechanism with rapid strength recovery. This article is part of the themed issue ‘Faulting, friction and weakening: from slow to fast motion’.

scholarly journals Novel analysis methods of dynamic properties for vehicle pantographs

2018 ◽  
Vol 180 ◽  
pp. 01005 ◽  
Author(s):  
Andrzej Wilk
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Simulation ◽  
High Speed ◽  
Dynamic Properties ◽  
Equations Of Motion ◽  
Computer Software ◽  
Fem Analysis ◽  
Electrical Energy ◽  
Modern Approach ◽  
Static And Dynamic Analysis

Transmission of electrical energy from a catenary system to traction units must be safe and reliable especially for high speed trains. Modern pantographs have to meet these requirements. Pantographs are subjected to several forces acting on their structural elements. These forces come from pantograph drive, inertia forces, aerodynamic effects, vibration of traction units etc. Modern approach to static and dynamic analysis should take into account: mass distribution of particular parts, physical properties of used materials, kinematic joints character at mechanical nodes, nonlinear parameters of kinematic joints, defining different parametric waveforms of forces and torques, and numerical dynamic simulation coupled with FEM calculations. In this work methods for the formulation of the governing equations of motion are presented. Some of these methods are more suitable for automated computer implementation. The novel computer methods recommended for static and dynamic analysis of pantographs are presented. Possibilities of dynamic analysis using CAD and CAE computer software are described. Original results are also presented. Conclusions related to dynamic properties of pantographs are included. Chapter 2 presents the methods used for formulation of the equation of pantograph motion. Chapter 3 is devoted to modelling of forces in multibody systems. In chapter 4 the selected computer tools for dynamic analysis are described. Chapter 5 shows the possibility of FEM analysis coupled with dynamic simulation. In chapter 6 the summary of this work is presented.

Vitrimer-based soft actuators with multiple responsiveness and self-healing ability triggered by multiple stimuli

Matter ◽  
2021 ◽  
Author(s):  
Yang Yang ◽  
Huimin Wang ◽  
Shuai Zhang ◽  
Yen Wei ◽  
Xiangming He ◽  
...  
Keyword(s):  
Self Healing ◽  
Soft Actuators
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