scholarly journals Development of modular and reconfigurable robot with multiple working modes

2021 ◽  
Author(s):  
Xiaojia He
Keyword(s):  
Force Control ◽  
Jacobian Matrix ◽  
Friction Compensation ◽  
Force Analysis ◽  
Passive Mode ◽  
Door Opening ◽  
Spherical Wrist ◽  
Reconfigurable Robot ◽  
The Common

A modular and reconfigurable robot (MRR) with multiple working modes for performing manipulation in uncontrolled environments is developed in this thesis. In the proposed MRR design, each joint module can independently work in active mode or passive mode. Major contributions of this thesis include the development of the passive mode with a unique friction compensation method and the use of force control in manipulation, such as door opening. In order to implement force control, the kinematics model and Jacobian matrix of the manipulator are derived by using the twist and wrench method, which is superior to the common D-H method, and the complete force analysis of the spherical wrist is presented as well. As a case study, the door opening process using force control is investigated by simulation and experiments. Door opening is successfully demonstrated using the developed MRR with multiple working modes.

scholarly journals Development of modular and reconfigurable robot with multiple working modes

2021 ◽  
Author(s):  
Xiaojia He
Keyword(s):  
Force Control ◽  
Jacobian Matrix ◽  
Friction Compensation ◽  
Force Analysis ◽  
Passive Mode ◽  
Door Opening ◽  
Spherical Wrist ◽  
Reconfigurable Robot ◽  
The Common

A modular and reconfigurable robot (MRR) with multiple working modes for performing manipulation in uncontrolled environments is developed in this thesis. In the proposed MRR design, each joint module can independently work in active mode or passive mode. Major contributions of this thesis include the development of the passive mode with a unique friction compensation method and the use of force control in manipulation, such as door opening. In order to implement force control, the kinematics model and Jacobian matrix of the manipulator are derived by using the twist and wrench method, which is superior to the common D-H method, and the complete force analysis of the spherical wrist is presented as well. As a case study, the door opening process using force control is investigated by simulation and experiments. Door opening is successfully demonstrated using the developed MRR with multiple working modes.

A multiple working mode approach to robotic hammering: Analysis and experiments

Robotica ◽  
2021 ◽  
pp. 1-13
Author(s):  
Vladyslav Romanyuk ◽  
Sina Soleymanpour ◽  
Guangjun Liu
Keyword(s):  
Limited Range ◽  
Service Robots ◽  
Mode Switching ◽  
Friction Compensation ◽  
Robot Arm ◽  
Free Rotation ◽  
Passive Mode ◽  
Space Robots ◽  
Reconfigurable Robot ◽  
Analytic Models

Abstract A robot arm may be in need for performing various operations, especially for service robots and space robots. This paper presents a strategy that allows a modular and reconfigurable robot to safely perform nail hammering without hardware enhancements. The purpose is to equip a versatile robot arm with hammering capability that can be used if needed. To do this, a multiple working mode approach is applied to switch the selected joint(s) to passive mode with friction compensation to allow free rotation during impact. Analytic impulse models are used to predict joint impulses and serve as criteria for mode switching. Advantages of the proposed approach include savings on space, weight, costs, and complexity for a limited range of nail/board environments. An experimental study has validated analytic models of hammering and demonstrated the effectiveness of the proposed approach.

scholarly journals A Multiple Working Mode Approach to Hammering With A Modular Reconfigurable Robot

2021 ◽  
Author(s):  
Vladyslav Romanyuk
Keyword(s):  
Experimental Study ◽  
Effective Mass ◽  
Limited Range ◽  
Mode Switching ◽  
Friction Compensation ◽  
Free Rotation ◽  
Passive Mode ◽  
Impulsive Forces ◽  
Reconfigurable Robot ◽  
Analytic Models

Robot joints could be damaged by impulsive forces due to impact when the robot performs hammering operations. This thesis presents the development of a strategy that allows a modular reconfigurable robot to safely perform nail hammering. To do this, a multiple working mode approach is applied to switch the selected joint(s) to passive mode with friction compensation to allow free rotation during impact. Analytic impulse models are used to predict joint impulses which can be computed offline or online and serve as criteria for mode switching. Joint impulses are constrained in case the hammer collides with such an object of infinite effective mass. Advantages of the proposed approach may include savings on space, weight, costs, and complexity for a limited range of nail/board environments. An experimental study validates analytic models of hammering and effectiveness of multiple working mode approach.

scholarly journals A Multiple Working Mode Approach to Hammering With A Modular Reconfigurable Robot

2021 ◽  
Author(s):  
Vladyslav Romanyuk
Keyword(s):  
Experimental Study ◽  
Effective Mass ◽  
Limited Range ◽  
Mode Switching ◽  
Friction Compensation ◽  
Free Rotation ◽  
Passive Mode ◽  
Impulsive Forces ◽  
Reconfigurable Robot ◽  
Analytic Models

Robot joints could be damaged by impulsive forces due to impact when the robot performs hammering operations. This thesis presents the development of a strategy that allows a modular reconfigurable robot to safely perform nail hammering. To do this, a multiple working mode approach is applied to switch the selected joint(s) to passive mode with friction compensation to allow free rotation during impact. Analytic impulse models are used to predict joint impulses which can be computed offline or online and serve as criteria for mode switching. Joint impulses are constrained in case the hammer collides with such an object of infinite effective mass. Advantages of the proposed approach may include savings on space, weight, costs, and complexity for a limited range of nail/board environments. An experimental study validates analytic models of hammering and effectiveness of multiple working mode approach.

Methodology for Analysis of Schottky Diode Failures

2010 ◽  
Author(s):  
Bhanu P. Sood ◽  
Michael Pecht ◽  
John Miker ◽  
Tom Wanek
Keyword(s):  
Failure Mode ◽  
Schottky Diode ◽  
Failure Modes ◽  
Schottky Diodes ◽  
Failure Mechanisms ◽  
Forward Voltage ◽  
Fast Switching ◽  
Voltage Drops ◽  
The Common

Abstract Schottky diodes are semiconductor switching devices with low forward voltage drops and very fast switching speeds. This paper provides an overview of the common failure modes in Schottky diodes and corresponding failure mechanisms associated with each failure mode. Results of material level evaluation on diodes and packages as well as manufacturing and assembly processes are analyzed to identify a set of possible failure sites with associated failure modes, mechanisms, and causes. A case study is then presented to illustrate the application of a systematic FMMEA methodology to the analysis of a specific failure in a Schottky diode package.

scholarly journals Getting information on suspended sediments in a large river from acoustic backscatter

2018 ◽  
Vol 40 ◽  
pp. 04017
Author(s):  
Adrien Vergne ◽  
Céline Berni ◽  
Jérôme Le Coz
Keyword(s):  
Suspended Sediment Concentration ◽  
Spatial Information ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Large River ◽  
Acoustic Backscatter ◽  
Qualitative Information ◽  
Sediment Size ◽  
The Common

There has been a growing interest in the last decade in extracting information on Suspended Sediment Concentration (SSC) from acoustic backscatter in rivers. Quantitative techniques are not yet effective, but acoustic backscatter already provides qualitative information on suspended sediments. In particular, in the common case of a bi-modal sediment size distribution, corrected acoustic backscatter can be used to look for sand particles in suspension and provide spatial information on their distribution throughout a river crosssection. This paper presents a case-study where these techniques have been applied.

scholarly journals Co-Management of Sewage Sludge and Other Organic Wastes: A Scandinavian Case Study

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3411
Author(s):  
Clara Fernando-Foncillas ◽  
Maria M. Estevez ◽  
Hinrich Uellendahl ◽  
Cristiano Varrone
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Resource Recovery ◽  
Organic Wastes ◽  
Industrial Wastes ◽  
Wastewater Management ◽  
Sewage Sludge Management ◽  
The Common ◽  
Green Chemicals

Wastewater and sewage sludge contain organic matter that can be valorized through conversion into energy and/or green chemicals. Moreover, resource recovery from these wastes has become the new focus of wastewater management, to develop more sustainable processes in a circular economy approach. The aim of this review was to analyze current sewage sludge management systems in Scandinavia with respect to resource recovery, in combination with other organic wastes. As anaerobic digestion (AD) was found to be the common sludge treatment approach in Scandinavia, different available organic municipal and industrial wastes were identified and compared, to evaluate the potential for expanding the resource recovery by anaerobic co-digestion. Additionally, a full-scale case study of co-digestion, as strategy for optimization of the anaerobic digestion treatment, was presented for each country, together with advanced biorefinery approaches to wastewater treatment and resource recovery.

unrechtliche peinliche schmehung oder dem gemeinen nutz nuetzlich?Eine Fallstudie zur Normenkonkurrenz im Schmähschriftprozess des 16. Jahrhunderts

2020 ◽  
Vol 25 (1) ◽  
pp. 135-149
Author(s):  
Jan Siegemund
Keyword(s):  
Early Modern ◽  
Common Good ◽  
Public Places ◽  
Legal Norms ◽  
The Public ◽  
The Common ◽  
The Public Sphere ◽  
The City ◽  
Different Levels

AbstractLibel played an important and extraordinary role in early modern conflict culture. The article discusses their functions and the way they were assessed in court. The case study illustrates argumentative spaces and different levels of normative references in libel trials in 16th century electoral Saxony. In 1569, Andreas Langener – in consequence of a long stagnating private conflict – posted several libels against the nobleman Tham Pflugk in different public places in the city of Dresden. Consequently, he was arrested and charged with ‘libelling’. Depending on the reference to conflicting social and legal norms, he had therefore been either threatened with corporal punishment including his execution, or rewarded with laudations. In this case, the act of libelling could be seen as slander, but also as a service to the community, which Langener had informed about potentially harmful transgression of norms. While the common good was the highest maxim, different and sometimes conflicting legally protected interests had to be discussed. The situational decision depended on whether the articulated charges where true and relevant for the public, on the invective language, and especially on the quality and size of the public sphere reached by the libel.

scholarly journals Mind the Gap: Why the Landscape Planning System in Sardinia Does Not Work

2021 ◽  
Vol 13 (13) ◽  
pp. 7300
Author(s):  
Anna Maria Colavitti ◽  
Alessio Floris ◽  
Sergio Serra
Keyword(s):  
Landscape Planning ◽  
Comparative Method ◽  
Poor Quality ◽  
Planning System ◽  
Local Planning ◽  
The Common ◽  
Regional Landscape ◽  
Landscape Protection

In Italy, after the introduction of the Code of Cultural Heritage and Landscape in 2004, the Regional Landscape Plan (RLP) has acquired a coordination role in the urban planning system, for the implementation of policies for landscape protection and valorisation. The case study of the RLP of Sardinia is a paradigmatic application to the coastal area of the island, which is considered most vulnerable and subject to settlement pressure. The objectives of preservation and valorisation of the territorial resources should be transferred into local planning instruments by adopting strategies aimed at the preservation of the consolidated urban fabric, at the requalification and completion of the existing built-up areas according to the principles of land take limitation and increase in urban quality. The paper investigates the state of implementation and the level of integration of landscape contents in the local plans that have been adapted to the RLP, using a qualitative comparative method. In addition, the results of the plan coherence checks, elaborated by the regional monitoring bodies after the adaptation process, have been analysed to identify the common criticalities and weaknesses. The results highlight the lack of effectiveness of the RLP, after more than a decade since its approval, considering the limited number of adequate local plans and the poor quality of their analytical and regulative contents in terms of landscape protection and valorisation. Conclusions suggest some possible ways to revise the RLP, focusing on the participation of local communities and the development of a new landscape culture.

scholarly journals Cable Tensile Forces Associated to Winch Design in Tethered Harvesting Operations: A Case Study from the Pacific North West

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 827
Author(s):  
Omar Mologni ◽  
Eric D. T. Nance ◽  
C. Kevin Lyons ◽  
Luca Marchi ◽  
Stefano Grigolato ◽  
...  
Keyword(s):  
Endurance Limit ◽  
Tensile Force ◽  
Force Analysis ◽  
North West ◽  
The Pacific ◽  
Work Tasks ◽  
Tensile Forces ◽  
System Activation ◽  
The Impact

Cable tensile forces in winch-assist harvesting have been investigated in order to assess the safety concerns of the technology. However, the literature is lacking, particularly in regards to the impact of winch design. In this study, a Summit Winch Assist tethering a feller-director on ground slopes up to 77% was monitored for four days. The cable tensile forces were simultaneously recorded at the harvesting and anchor machine at a frequency of 100 Hz. Cameras and GNSS devices enabled a time study of the operations and the recording of machine positions. Winch functionality and design were disclosed by the manufacturer and used for the interpretation of the results. The cable tensile forces reached 296 kN at the harvesting machine and 260 kN at the anchor machine. The slow negotiation of obstacles while moving downhill recorded the highest peaks, mainly due to threshold settings of the winch in the brake system activation. Lower but significant peaks were also recorded during stationary work tasks. The peaks, however, were limited to a few events and never exceeded the endurance limit of the cable. Overall, the study confirmed recent findings in cable tensile force analysis of active winch-assist operations and provided evidence of the underlaying mechanisms that contribute to cable tensile forces.

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