Mass Estimation of Self-Contained Linear Electro-Hydraulic Actuators and Evaluation of the Influence on Payload Capacity of a Knuckle Boom Crane

2019 ◽  
Author(s):  
Søren Ketelsen ◽  
Torben Ole Andersen ◽  
Morten Kjeld Ebbesen ◽  
Lasse Schmidt
Keyword(s):  
Hydraulic Cylinder ◽  
The Self ◽  
Limiting Factor ◽  
Hydraulic Circuit ◽  
Hydraulic Power ◽  
Payload Capacity ◽  
Hydraulic Cylinders ◽  
Boom Crane ◽  
Valve Actuation

Abstract Self-contained linear hydraulic drives are characterized by having integrated the hydraulic power unit e.g. electrical prime mover, hydraulic pumps etc. and the hydraulic cylinder in a single compact unit. Compared to the hydraulic cylinder itself, the mass of the self-contained linear actuator is significantly larger. For some applications, e.g. crane manipulators the additional mass of the actuators compared to conventional valve-controlled hydraulics, may reduce the payload capacity, which is a central performance parameter. As a case study, a medium sized two link knuckle boom crane is modelled and by assuming the force capability of the hydraulic cylinders to be the limiting factor, the reduction in payload capacity is examined if replacing the knuckle boom cylinder with a self-contained hydraulic cylinder drive. By focusing on seven different hydraulic circuit architectures, this study estimates the mass of compact pump-controlled actuators and investigates to what extent the choice of system topology affects the mass of the actuator, and thus payload capacity of the crane. The results show that the choice of hydraulic circuit architecture may affect both the required amount of installed power and the mass of the self-contained actuator. For the considered knuckle boom crane the estimated mass of the needed 59 kW self-contained actuator ranges from 2300 kg to 2521 kg depending on the hydraulic circuit architecture. The mass of the hydraulic cylinder itself used for conventional valve actuation is estimated to 1674 kg. If the entire working range is considered, installing the heavier self-contained actuator reduces the payload capacity with up to 3 % compared to conventional valve actuation.

scholarly journals A Self-Contained Electro-Hydraulic Cylinder with Passive Load-Holding Capability

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 292 ◽  
Author(s):  
Damiano Padovani ◽  
Søren Ketelsen ◽  
Daniel Hagen ◽  
Lasse Schmidt
Keyword(s):  
Energy Efficiency ◽  
Cost Efficiency ◽  
Tracking Error ◽  
Hydraulic Cylinder ◽  
Position Tracking ◽  
Hydraulic Systems ◽  
Practical Applications ◽  
Hydraulic Cylinders ◽  
External Loads ◽  
Boom Crane

Self-contained electro-hydraulic cylinders have the potential to replace both conventional hydraulic systems and the electro-mechanical counterparts enhancing energy efficiency, plug-and-play installation, and reduced maintenance. Current commercial solutions of this technology are limited and typically tailor-made, whereas the research emphasis is primarily on cost efficiency and power applications below five [kW]. Therefore, there is the need of developing more flexible systems adaptable to multiple applications. This research paper offers a contribution in this regard. It presents an electro-hydraulic self-contained single-rod cylinder with passive load-holding capability, sealed tank, capable of recovering energy, and scalable up to about eighty [kW]. The system implementation on a single-boom crane confirms its feasibility: The position tracking error remains well within ±2 [mm], oscillations are limited, and the overall energy efficiency is about 60 [%] during actuation. Concerning the passive load-holding devices, it is shown that both vented and non-vented pilot-operated check valves achieve the desired functioning and can hold the actuator position without consuming energy. Additional observations about the size and the arrangement of the load-holding valves are also provided. In conclusion, this paper demonstrates that the proposed self-contained cylinder can be successfully extended to several practical applications, especially to those characterized by overrunning external loads and the need of securing the actuator position.

The Hydraulic Jack-Up System Design on the Ocean Petroleum Platform 161 - the First Self-Installing Product Platforms in China

2011 ◽  
Vol 201-203 ◽  
pp. 1015-1018
Author(s):  
De Tang Li ◽  
Hai Qing Tian ◽  
Yue Pai Wang ◽  
Yuan Yu Huang
Keyword(s):  
System Design ◽  
Hydraulic Cylinder ◽  
Product Platform ◽  
Hydraulic Jack ◽  
Hydraulic Power ◽  
Proportional Valve ◽  
Product Platforms ◽  
Production Platform ◽  
Hydraulic Cylinders ◽  
Jack Up

The paper introduces the hydraulic jack-up system design about the first domestic self-installing product platform. According to the production platform features, the jack-up system chooses the mode of hydraulic cylinder driving. So the jack-up system is both economy and safe reliability. The jack-up system is equipped with proportional valve and the PLC programmable controller which has a touch panel to show the inclination of the platform, the synchronism of hydraulic cylinders in the four legs of the platform, the state of the piston pin and the alarm indication of the hydraulic power station etc.

AAC Collaboration Using the Self-Anchored Rating Scales (SARS): An Aphasia Case Study

2012 ◽  
Vol 21 (4) ◽  
pp. 136-143
Author(s):  
Lynn E. Fox
Keyword(s):  
Augmentative And Alternative Communication ◽  
Rating Scales ◽  
Rating Scale ◽  
Therapeutic Process ◽  
Family Counseling ◽  
The Self ◽  
Alternative Communication ◽  
Her Family ◽  
Solution Focused

Abstract The self-anchored rating scale (SARS) is a technique that augments collaboration between Augmentative and Alternative Communication (AAC) interventionists, their clients, and their clients' support networks. SARS is a technique used in Solution-Focused Brief Therapy, a branch of systemic family counseling. It has been applied to treating speech and language disorders across the life span, and recent case studies show it has promise for promoting adoption and long-term use of high and low tech AAC. I will describe 2 key principles of solution-focused therapy and present 7 steps in the SARS process that illustrate how clinicians can use the SARS to involve a person with aphasia and his or her family in all aspects of the therapeutic process. I will use a case study to illustrate the SARS process and present outcomes for one individual living with aphasia.

scholarly journals Self-Categorising and Othering in Migrant Integration: The Case of Entrepreneurs in Berlin

2021 ◽  
Vol 13 (4) ◽  
pp. 2145
Author(s):  
Lubna Rashid ◽  
Silvia Cepeda-García
Keyword(s):  
Economic Integration ◽  
The Self ◽  
Migrant Entrepreneurship ◽  
Migrant Integration

The economic integration of migrants has become increasingly prioritised by European governments. However, Europe’s colonial past and orientalist narratives have contributed to the inevitable othering of migrants, even in the minds of those with the best of intentions. Guided by the self-categorisation theory, we postulate that those involved in supporting migrants to integrate in European societies implicitly categorise them as an out-group, potentially leading to suboptimal integration outcomes and the (inadvertent) exclusion of the very migrants they attempt to integrate. A case study of migrant entrepreneurship support initiatives in Berlin is illustrated as a qualitative, empirical example, providing some evidence for those arguments. The paper concludes with recommendations for practitioners and suggestions for further research.

The Lower Extremity Exoskeleton Coordinated Control Method Based on Human Electromechanical Coupling

2012 ◽  
Vol 220-223 ◽  
pp. 1012-1017
Author(s):  
Qing Guo ◽  
Dan Jiang
Keyword(s):  
Lower Extremity ◽  
Electromechanical Coupling ◽  
Position Control ◽  
Control Method ◽  
Angular Displacement ◽  
Stability Margin ◽  
Hydraulic Cylinder ◽  
Load Force ◽  
Hydraulic Cylinders ◽  
Coupling Characteristics

This paper has introduced electromechanical coupling characteristics in the lower extremity exoskeleton systems, considered model ,according to legs supporting gait when people walking, established the load torque compensation model , and a mathematical model of knee position control system which is made of the servo valve, hydraulic cylinders and other hydraulic components, designed hydraulic cylinder position control loop in case of existing load force interference compensation, and used the method of combining the PID and lead correction network for frequency domain design ,ensured system to meet a certain stability margin. The simulation results show that this position control method can servo on the knee angular displacement of normal human walking, reached a certain exoskeleton boost effect, at the same time, met the needs of human-machine coordinated motion.

scholarly journals Storytelling and `Character': Victims, Villains and Heroes in a Case of Technological Change

Organization ◽  
2009 ◽  
Vol 16 (3) ◽  
pp. 425-442 ◽  
Author(s):  
Andrea Whittle ◽  
Frank Mueller ◽  
Anita Mangan
Keyword(s):  
Organizational Change ◽  
Technological Change ◽  
Moral Status ◽  
The Self ◽  
Routine Work ◽  
Social Positioning ◽  
Face Saving ◽  
Positive Light

In this article we examine the role of stories in the temporal development of images of the self at work. Drawing on an in-depth case study of technological change in a UK public-private partnership, we highlight the role of stories in the construction, maintenance and defence of actors' moral status and organizational reputation. The analysis focuses on the development of one `character' as he shifted from the role of innocent victim to implied villain to heroic survivor within the stories constructed during routine work conversations. We argue that stories are intimately linked to the forms of `moral accounting' that serve to deal with the challenges to `face' and social positioning that accompany `failed' organizational change. Stories, we suggest, are likely to be invoked when an interactional encounter threatens the participants' sense of social worth. Stories in which we present ourselves in a positive light—for instance as virtuous, honourable, courageous, caring, committed, competent— comprise a key component of face-saving strategies designed to maintain our social positioning: processes that are often intensified during periods of organizational change.

Development of hydraulic cylinder diagnostic methods by modeling methods

2021 ◽  
pp. 41-45
Author(s):  
Keyword(s):  
Hydraulic Drive ◽  
Hydraulic Cylinder ◽  
Technical Condition ◽  
Diagnostic Methods ◽  
Technical Diagnostics ◽  
Remaining Service Life ◽  
Construction Machine ◽  
Piston Speed ◽  
Variable Nature ◽  
Hydraulic Cylinders

The hydraulic drive of a construction machine is a complex dynamic system that is subjected to many dynamic loads of a variable nature and operates under conditions of variable external influences caused by various factors. During operation, these loads cause failure of the hydraulic transmission elements. To prevent these malfunctions, technical diagnostics should be applied by determining their current technical condition and remaining service life. The article assesses the working condition of hydraulic cylinders using a mathematical model. Using matlab/simulink software to simulate the hydraulic cylinder and hydraulic piston speed when changing the hydraulic cylinder clearance. The simulation results are presented. Keywords: diagnostic, hydraulic cylinder, simulation, development

Self-Hardening of a Gypsum

2017 ◽  
Vol 737 ◽  
pp. 517-521 ◽  
Author(s):  
Victoriya Petropavlovskaya ◽  
Аleksandr Buryanov ◽  
Тatyana Novichenkova ◽  
Kirill Petropavlovskii
Keyword(s):  
Mechanical Properties ◽  
Calcium Sulfate ◽  
The Self ◽  
Limiting Factor ◽  
Sulfate Formation

In this article the self-hardening structure of stone based on calcium sulfate formation is described. Increase of strength of gypsum is possible by additional reinforcing of a stone ettringite crystals. The form and character of the formed crystals is defined by size рН. Dependence рН from the maintenance of additives was investigated in work. The limiting factor of formation of crystals of an ettringite of a necessary look is the maintenance of an additive. In work gypsum composites with the improved physical-mechanical properties on the basis of the modifying complex are received and investigated.

scholarly journals Rethinking the Perceived Self: Samples from Facebook

2014 ◽  
Vol 9 (1) ◽  
pp. 209-228
Author(s):  
Anita Kasabova
Keyword(s):  
Social Media ◽  
Cultural Differences ◽  
The Self ◽  
Age Group ◽  
Active Participant ◽  
The Real ◽  
Group I ◽  
Self Knowledge ◽  
Anglo American

Abstract How the self perceives reality is a traditional topic of research across several disciplines. I examine the perceived self on Facebook, as a case-study of self-knowledge on „classical” social media. Following Blascovich & Bailenson (2011), I consider the distinction between the real and the virtual as relative. Perceptual self-knowledge, filtered through social media, requires rethinking the perceived self in terms of social reality (Neisser, 1993). This claim dovetails Jenkins’s (2013) notion of the self as an active participant in consumption. I argue that the perceived self in social media could be conceived in terms of how it would like to be perceived and appraised by its virtual audience. Using Neisser’s (1993) typology of self-knowledge and Castañeda’s (1983) theory of I-guises, I analyse seven samples from Anglo-American and Bulgarian Facebook sites and show that the perceived self produces itself online as a captivating presence with a credible story. My samples are taken from FB community pages with negligible cultural differences across an online teenage/twens (twixter) age group. I then discuss some problematic aspects of the perceived self online, as well as recent critiques of technoconsumerism.

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