An Energetic Control Methodology for Exploiting the Passive Dynamics of Pneumatically Actuated Hopping

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Yong Zhu ◽  
Eric J. Barth
Keyword(s):  
Energy Dissipation ◽  
Control Strategy ◽  
Pneumatic Cylinder ◽  
Passive Dynamics ◽  
System A ◽  
Actuation System ◽  
Lower Chamber ◽  
Nonideal System ◽  
Control Methodology ◽  
Upper Chamber

This paper presents an energetically derived control methodology to specify and regulate the oscillatory motion of a pneumatic hopping robot. An ideal lossless pneumatic actuation system with an inertia is shown to represent an oscillator with a stiffness, and hence frequency, related to the equilibrium pressures in the actuator. Following from an analysis of the conservative energy storage elements in the system, a control methodology is derived to sustain a specified frequency of oscillation in the presence of energy dissipation. The basic control strategy is to control the pressure in the upper chamber of the pneumatic cylinder to specify the contact time of the piston, while controlling the total conservative energy stored in the system to specify the flight time and corresponding flight height of the cylinder. The control strategy takes advantage of the natural passive dynamics of the upper chamber to provide much of the required actuation forces and natural stiffness, while the remaining forces needed to overcome the energy dissipation present in a nonideal system with losses are provided by a nonlinear control law for the charging and discharging of the lower chamber of the cylinder. Efficient hopping motion, relative to a traditional nonconservative actuator, is achieved by allowing the energy storing capability of a pneumatic actuator to store and return energy to the system at a controlled specifiable frequency. The control methodology is demonstrated through simulation and experimental results to provide accurate and repeatable hopping motion for pneumatically actuated robots in the presence of dissipative forces.

Energy-Based Control of a Pneumatic Oscillator With Application to Energy Efficient Hopping Robots

2006 ◽  
Author(s):  
Yong Zhu ◽  
Eric J. Barth
Keyword(s):  
Energy Dissipation ◽  
Amplitude Control ◽  
Pneumatic Actuation ◽  
System A ◽  
Actuation System ◽  
Ideal System ◽  
Energetic Analysis ◽  
Control Methodology ◽  
Nonlinear Control Law ◽  
Vertical Case

This paper presents an energetically derived control methodology to specify and regulate the frequency and amplitude of oscillatory motion of a pneumatic actuation system. A lossless horizontal pneumatic actuation system with an inertia is energetically shown to represent an oscillator with a stiffness, and hence frequency, related to the equilibrium pressures in the actuator. Following from an analysis of the conservative energy storage elements in the system, a control methodology is derived to sustain a specified frequency and amplitude of oscillation in the presence of energy dissipation. The control strategy takes advantage of the natural passive dynamics of the system to provide much of the required actuation forces, while the remaining forces needed to overcome the energy dissipation present in a non-ideal system with losses are provided by a nonlinear control law for the charging and discharging of the actuator. This control methodology is demonstrated experimentally to provide accurate and repeatable frequency and amplitude control of oscillation in the presence of dissipative forces. Finally, the energetic analysis of the horizontal pneumatic system is extended to the vertical case where gravity is present. This extension provides an energetically efficient hopping control methodology for pneumatically actuated robots.

A Novel Deployable Hexahedron Mobile Mechanism Constructed by Only Prismatic Joints

2013 ◽  
Vol 5 (4) ◽  
Author(s):  
Wan Ding ◽  
Yan-an Yao
Keyword(s):  
Control Strategy ◽  
Stable State ◽  
Necessary Condition ◽  
Pneumatic Cylinder ◽  
Symmetrical Structure ◽  
System A ◽  
Prismatic Joints ◽  
Binary Control ◽  
The Stability ◽  
Pneumatic Cylinders

This paper proposes a novel deployable hexahedron mobile mechanism that is rigidly linked by only prismatic joints. The mechanism that is a completely symmetrical structure can always keep the walking capability when any of its six faces of the hexahedron touches the ground. It can roll at any stable state. The configuration constructed by only prismatic joints makes it expand and contract as a deployable structure. In this paper, a method for constructing a deployable hexahedron mobile mechanism is proposed. The stability analysis and dynamic simulation of the walking and rolling are carried out. The necessary condition of tipping motion and the speed analysis of two different rolling gaits are studied in details. A binary control strategy is adopted to simplify the complexity of the control system. A pneumatic cylinder is chosen to be the binary actuator. A prototype composed of 180 pneumatic cylinders was fabricated. The validity of the walking and tipping functions are verified by the experimental results.

Towards a new design with generic modeling and adaptive control of a transformable quadrotor

2021 ◽  
pp. 1-31
Author(s):  
S.H. Derrouaoui ◽  
Y. Bouzid ◽  
M. Guiatni
Keyword(s):  
Adaptive Control ◽  
Control Strategy ◽  
Experimental Tests ◽  
Generic Model ◽  
System Control ◽  
System A ◽  
Viable Solution ◽  
Generic Modeling ◽  
Adaptive Control Strategy ◽  
The Stability

Abstract Recently, transformable Unmanned Aerial Vehicles (UAVs) have become a subject of great interest in the field of flying systems, due to their maneuverability, agility and morphological capacities. They can be used for specific missions and in more congested spaces. Moreover, this novel class of UAVs is considered as a viable solution for providing flying robots with specific and versatile functionalities. In this paper, we propose (i) a new design of a transformable quadrotor with (ii) generic modeling and (iii) adaptive control strategy. The proposed UAV is able to change its flight configuration by rotating its four arms independently around a central body, thanks to its adaptive geometry. To simplify and lighten the prototype, a simple mechanism with a light mechanical structure is proposed. Since the Center of Gravity (CoG) of the UAV moves according to the desired morphology of the system, a variation of the inertia and the allocation matrix occurs instantly. These dynamics parameters play an important role in the system control and its stability, representing a key difference compared with the classic quadrotor. Thus, a new generic model is developed, taking into account all these variations together with aerodynamic effects. To validate this model and ensure the stability of the designed UAV, an adaptive backstepping control strategy based on the change in the flight configuration is applied. MATLAB simulations are provided to evaluate and illustrate the performance and efficiency of the proposed controller. Finally, some experimental tests are presented.

Virtual Coupling Control Method for Robotic Gait

2013 ◽  
Vol 278-280 ◽  
pp. 629-632
Author(s):  
Li Peng Yuan ◽  
Amur Al Yahmedi ◽  
Li Ming Yuan
Keyword(s):  
Energy Dissipation ◽  
Hybrid Model ◽  
Control Strategy ◽  
Control Method ◽  
Mechanical Energy ◽  
Control Laws ◽  
Gait Patterns ◽  
Walking Gait ◽  
Virtual Coupling ◽  
Mechanical Energy Dissipation

Here, we consider the walking gait patterns. And we presented a hybrid model for a passive 2D walker with knees and point feet. The dynamics of this model were fully derived analytically. We have also proposed virtual coupling control laws. The control strategy is formed by taking into account the features of mechanical energy dissipation and restoration. And we also prove some walking rules maybe true.

scholarly journals Modeling and Implementation of MPPT based Wind Energy System Using Cuckoo Search

2018 ◽  
Vol 7 (2.7) ◽  
pp. 671
Author(s):  
Kaleem SK ◽  
Rama Subbanna S
Keyword(s):  
Wind Energy ◽  
Control Strategy ◽  
Cuckoo Search ◽  
Energy System ◽  
System A ◽  
Wind Turbine System ◽  
Proposed Model ◽  
Wind Energy System ◽  
Mppt Controller ◽  
And Performance

This paper presents adjustable speed generators for wind turbines. In order to improve the potential and performance of wind turbine system this paper proposes a concept DFIG. Generally wind nature is not fixed it varies linearly w.r.t time, hence, a MPPT controller is proposed in this paper. This paper presents the DFIG wind energy system. A Control strategy implemented and controlled by framing rotor reference frame axis in terms of direct and quadrature axis coordinates. A PI based RSC and GSC controllers are introduced to control the power through the wind system to grid. This proposed model is implemented and verified by using Matlab/Simulink.  

MATLAB Simulation of Autonomous Servo Driven Oil-Hydraulic Power Unit

2016 ◽  
Author(s):  
Eurico Seabra ◽  
Jorge Costa ◽  
Hélder Puga ◽  
Celina Leão
Keyword(s):  
Power Unit ◽  
Control Strategy ◽  
High Efficiency ◽  
Gear Pump ◽  
Hydraulic Circuit ◽  
Servo Motor ◽  
Hydraulic Power ◽  
Hydraulic Accumulator ◽  
Control Methodology ◽  
Internal Gear

Servo driven hydraulic power units have been implemented in some sectors of industry in order to counteract rising energy costs and reduce our ecological footprint. The advantages associated with the use of these technologies has motivated us to research a new control approach that allows its use independently, with reduced implementation costs and high efficiency. This investigation develops new solutions to concurrently implement and improve volumetric control methodology for oil-hydraulic power units, which aims to produce and provide strictly necessary hydraulic power to the actuators. The approach used is based on a balance of flows present in a hydraulic circuit, reducing the pressure ripple generated by the pumps, valves and actuators, using a hydraulic accumulator. The work begins with the mathematical modeling of a volumetric oil-hydraulic power unit, designed to demonstrate the concepts of the project, its components and the associated advantages. The definitions of the models presented are intended to exemplify the new control strategy and infer about the possibilities that arise from the use of this new methodology for power oil-hydraulic units. In order to carry out the research and conclude about the results of the simulations, two simulations were performed using MATLAB Simulink software for two distinct hydraulic circuits and their control strategy: resistive control and volume control with the use of a servo motor. In the resistive control, an internal gear pump driven by an induction motor with constant speed uses a pressure regulating valve to derive the excess of the flow to the reservoir. Despite their low efficiency, this type of assembly has very low costs and has a very good dynamic compared with traditional volumetric drive systems, avoiding the use of dedicated engineering. The volumetric control makes use of an internal gear pump (to allow direct comparisons with the resistive control method), a servo motor, a hydraulic accumulator and a directional valve which prevent the flow from de accumulator draining into the reservoir during the downtimes. The controller allows you to establish a direct relationship between the accumulator volume and pressure of the hydraulic circuit. The control methodology discussed throughout this work reveals an alternative volumetric control solution to consider, whether in new equipment or in retrofitting even with the different objectives of existing technologies available in the market. The simulations allow us to conclude on energy-saving and environmental advantages of the volumetric control system presented, comparing it with existing systems on the market.

Research on Dynamic Authorization Access Control Strategy Model of Distributed Multi-Organization MIS

2012 ◽  
Vol 263-266 ◽  
pp. 1461-1466
Author(s):  
Xiao Ming Meng ◽  
Jian Hua Zhang
Keyword(s):  
Access Control ◽  
Control Strategy ◽  
Control Process ◽  
Shared Resources ◽  
Organization Management ◽  
System A ◽  
Multi Stage ◽  
Strategy Model ◽  
Key Terms ◽  
Dynamic Authorization

Focus on the problem of dynamic authorization access control of Distributed Multi-Organization Management Information System (DMOMIS), the system resources are divided into two kinds: relatively independent resources and shared resources. These two kinds of resources were used different authorization system to authorize. The relatively independent resources were authorized by using distributed authorization system (DA), and the similar and shared resources were authorized by using authorized system (A). According to the key terms definition, the system hypothesis and the idea of dynamic programming, then the dynamic authorization access control process of DMOMIS was abstracted as a multi stage users authorization process based on resources, and put out the dynamic authorization access control strategy model of DMOMIS, at last, depicted its execution process.

Abstract 340: Recombinant Soluble Apyrase Inhibits Vascular Smooth Muscle Cell Migration

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Oluwaseun Adeola ◽  
Yan Ji ◽  
Phillip Fish ◽  
Tammy Strawn ◽  
Gary A Weisman ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Cell Migration ◽  
Endothelial Cell ◽  
Purinergic Receptor ◽  
Neointimal Hyperplasia ◽  
Receptor Activation ◽  
Vehicle Control ◽  
Extracellular Nucleotides ◽  
Lower Chamber ◽  
Upper Chamber

Background: Purinergic receptor activation by extracellular nucleotides is involved in thrombosis and neointimal hyperplasia that accompany atherosclerosis and postangioplasty restenosis. Human apyrases [ecto-nucleoside triphosphate diphosphohydrolase (E-NTPDases)] are membrane bound enzymes that hydrolyze extracellular nucleotides, thereby inhibiting purinergic receptor activation. CD39, the first identified human apyrase, is constitutively expressed on endothelial cell (EC) and vascular smooth muscle cell (VSMC) surfaces. APT102, a recombinant soluble form of CD39L3, has been shown to reduce platelet activation through its ADPase activity, but its effects on VSMC and EC function are yet to be established. We tested the hypothesis that APT102 will inhibit migration of VSMCs and ECs. Methods: We studied cell migration using a modified Boyden chamber assay in which 5x10 4 cells suspended in 0.2% FBS/DMEMF12 were added to the upper chamber of transwells separated from the lower chamber medium by a microporous membrane through which VSMCs and ECs can migrate. APT102 (100 nM) or vehicle control was added to the upper chamber; lower chamber contained 2.5% FBS/DMEMF12 and either ATP (10 μM) or vehicle control. Transwells were incubated at 37 0 C for 6 h, after which cells that migrated through pores and adhered to the lower chamber side of the membrane were fixed, stained and counted. Results: ATP (10μM) significantly enhanced migration of both VSMCs and ECs. APT102 significantly inhibited VSMC migration and completely abrogated the pro-migratory effect of ATP. In contrast, APT102 had no inhibitory effect on EC migration, either spontaneous or ATP-enhanced. Conclusion: APT102 inhibits VSMC but not EC migration. These results suggest that pharmacological targeting of extracellular nucleotides may provide a safe and effective therapeutic strategy to inhibit neointimal hyperplasia and restenosis after angioplasty, without delaying endothelial cell recovery, which is a significant limitation of drug-eluting stents. Further studies are needed to clarify the mechanism(s) underlying the differential effect of extracellular nucleotide degradation by APT102 on VSMC and EC migration.

Sejm Rzeczypospolitej Obojga Narodów 1572–1668

2021 ◽  
Vol 6(167) ◽  
pp. 85-114
Author(s):  
Edward Opaliński
Keyword(s):  
Degradation Process ◽  
Lower Chamber ◽  
First Time ◽  
Upper Chamber ◽  
State Territory ◽  
Chamber Of Deputies

In 1572–1668 the Sejm of the Commonwealth of Two Nations underwent constant evolution. The greatest changes occurred at the time of the first interregnum (1572–74) after the death of the last Jagiellonian monarch – Zygmunt Augustus (1572). This was the time of the emergence of two types of new Sejms (convocation and election ones), functioning exclusively during the interregnum. The Henrician Articles (1574) resolved that the Sejm was to debate only for six weeks, and that the monarch was compelled to convoke it at least once every two years. The extraordinary Sejm was established in 1613 – it could be convened in cases of urgent needs and it sat for two or three weeks. The Parliament was composed of three estates: the king, the Senate, and the deputies as well as two chambers. The upper chamber (Senate) consisted of senators nominated by the monarch on a lifelong basis, and the lower chamber (Chamber of Deputies) – of deputies of the noble estate elected at pre-Sejm sejmiks (Polish: sejmiki). An integral part of the Parliament was composed of the Sejm court, both appellant and trying gravest crimes. The Crown and Lithuanian Tribunal, established in 1578–81, assumed appellation competences from the Sejm court. Tribunal judges were elected every year for a year-long term of office at special sejmiks known as deputational or deputy (judicial), which constituted a forum; here deputies presented to the voters accounts of their parliamentary activity. At the turn of 1591, post-Sejm or relational (debriefing) sejmiks were convened after the closure of the Sejm debates; here deputies presented reports concerning their parliamentary activities. The growing composition of the Parliament was associated with an expansion of state territory as a result of victorious wars waged against Muscovy. New bishoprics, voivodeships, and sejmiki were established. There were 140 senators in 1572, and 150 during the 1630s. Analogously, the number of deputies grew from 166 to 180. The Sejm acted upon the basis of a consensus, and thus was obligated to take into account the stand of the minorities. In 1652, the protest of a single deputy for the first time rendered further Sejm debates impossible. From then on, the Polish-Lithuanian Parliament constantly succumbed to a degradation process.

Sign in / Sign up

Export Citation Format

Share Document