scholarly journals Dynamics of Single-Action Pneumatic Actuators

2020 ◽  
Author(s):  
Michał Bartyś
Keyword(s):  
Energy Conversion ◽  
Mechanical Energy ◽  
Experiment Data ◽  
Pneumatic Actuators ◽  
Single Action ◽  
Large Step ◽  
Nonlinear Analytical Model ◽  
Pneumatic Transducer ◽  
The Asymmetry ◽  
Working Hypotheses

The asymmetry in the dynamics of an electro-pneumatic actuating device consisting of an electro-pneumatic transducer and a single-action pneumatic actuator was unexpectedly found experimentally. This asymmetry manifests in response to large step excitations. The dynamic asymmetry effect is understood as a change in the shape of the response of an actuator depending on the direction of the actuators stem movement. The questions appears: How to explain this effect? Does this phenomenon reflect thermodynamic air processes? Is it connected with air-to-mechanical energy conversion? Together, six working hypotheses explaining this effect were formulated. The asymmetry was studied in detail using analytical and simulation modeling, as well as experimental research. In this respect, a nonlinear analytical model was developed, tuned, and later solved using simulations. The simulation model was verified based on the experiment data. In addition, the problem of the efficiency in the energy conversion of a single-action actuator was discussed and, in result, the maximum theoretical energy efficiency was determined. Subsequently, all six working hypotheses were verified. Finally, the hypothesis explaining asymmetry as an effect of the different thermodynamic air processes in both actuator’s stem travel directions was confirmed.

scholarly journals Performance Characteristics in Runner of an Impulse Water Turbine with Splitter Blade

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 303
Author(s):  
Lingdi Tang ◽  
Shouqi Yuan ◽  
Yue Tang ◽  
Zhijun Gao
Keyword(s):  
Energy Conversion ◽  
Flow Direction ◽  
Mechanical Energy ◽  
Experimental Tests ◽  
High Energy ◽  
Negative Energy ◽  
Water Turbine ◽  
Conversion Performance ◽  
Water Turbines ◽  
Current Energy

The impulse water turbine is a promising energy conversion device that can be used as mechanical power or a micro hydro generator, and its application can effectively ease the current energy crisis. This paper aims to clarify the mechanism of liquid acting on runner blades, the hydraulic performance, and energy conversion characteristics in the runner domain of an impulse water turbine with a splitter blade by using experimental tests and numerical simulations. The runner was divided into seven areas along the flow direction, and the power variation in the runner domain was analyzed to reflect its energy conversion characteristics. The obtained results indicate that the critical area of the runner for doing the work is in the front half of the blades, while the rear area of the blades does relatively little work and even consumes the mechanical energy of the runner to produce negative work. The high energy area is concentrated in the flow passage facing the nozzle. The energy is gradually evenly distributed from the runner inlet to the runner outlet, and the negative energy caused by flow separation with high probability is gradually reduced. The clarification of the energy conversion performance is of great significance to improve the design of impulse water turbines.

Power Harvesting from the Vibration-Induced by the Piezoelectric Stator of Traveling Wave Rotary Ultrasonic Motor

2011 ◽  
Vol 317-319 ◽  
pp. 616-620 ◽  
Author(s):  
Guang Qing Wang ◽  
Zhong Wei Zhao
Keyword(s):  
Energy Conversion ◽  
Analytical Model ◽  
Traveling Wave ◽  
Mechanical Energy ◽  
Ultrasonic Motor ◽  
Maximum Output ◽  
Induced Voltage ◽  
Power Harvesting ◽  
Conversion Model ◽  
The Relationship

In this article, a novel electro-mechanical energy conversion model of power harvesting from the vibration-induced the piezoelectric stator of the traveling wave rotary ultrasonic motor was proposed. Based on the curvature basis approach, the relationship between the deduced voltage and the mechanical stain induced by piezoelectric polarization was formulated. In addition to the relationships between the maximum induced voltages at the resonance frequency, the conversion energy density and the dimensions of the piezoelectric stator were also derived. The analytical model shows that the vibration-induced voltage is proportional to the exciting electrical voltage magnitude and square of height of the piezoelectric ceramic (PZT) but is inversely proportional to the permittivity of PZT and the damping coefficient of the stator. Some simulations and experimental results demonstrate that the maximum output voltage coincides with the energy conversion analytical model.

scholarly journals Heterogenic Autotuner for Electro-Pneumatic Single-Action Actuators

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4604
Author(s):  
Michał Bartyś
Keyword(s):  
Pid Controller ◽  
The Novel ◽  
Main Concept ◽  
Heuristic Knowledge ◽  
Pneumatic Actuators ◽  
Single Action ◽  
Long Time ◽  
Qualitative Knowledge ◽  
Tuning Process ◽  
And Control

The main concept is to design the novel autotuner in a way that it will introduce benefits that arise from the effect of the fusion of the quantitative and qualitative knowledge gained from identification experiments, long-time expertise, and theoretical findings. The novelty of this approach is in the manner in which the expert heuristic knowledge is used for the development of an easy-to-use and time-efficient tuning process. In the proposed approach, the positioner simply learns, mimics, and follows up the tuning process that is performed by an experienced human operator. The major strength of this approach is that all parameters of positioner PID controller can be estimated by only identifying one single parameter that is the effective time constant of the pneumatic actuator. The elaborated autotuning algorithm is experimentally examined with different commercially available pneumatic actuators and control valves. The obtained results demonstrate that the proposed autotuning approach exhibits good performance, usability, and robustness. This should be considered as particularly relevant in the processes of installing, commissioning, and servicing single-action final control elements.

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