Performance Evaluation for Cable Direct Driven Robot

2014 ◽  
Author(s):  
Giovanni Boschetti ◽  
Alberto Trevisani
Keyword(s):  
Performance Evaluation ◽  
Performance Index ◽  
Parallel Robots ◽  
Performance Evaluations ◽  
Cable Tension ◽  
Cable Robot ◽  
Performance Indexes ◽  
Specific Direction ◽  
Moving Platform ◽  
Cable Forces

The evaluation of cable robot performances cannot neglect the considerable limitations introduced by cable tension bilateral bounds, i.e. the fact that neither negative nor limitless cable forces can be exerted. Therefore, such constraints must be explicitly accounted for and the indexes typically employed for parallel robots cannot be employed straightforwardly. In this work, instead of proposing a new performance index, we introduce an approach to performance evaluations which is based on the computation of the maximum force, along a specific direction, which can be exerted by the cables on the moving platform of a fully actuated or redundant cable robot. Such a computation, once extended to the whole workspace of a robot or, if needed, to any direction, openly and effectively describes the robot performances and can be extremely useful in practice. The application of the method to two fully actuated and fully constrained planar cable robots, together with a comparison with popular performance indexes, gives evidence of the method effectiveness.

scholarly journals Parallel Robot Translational Performance Evaluation through Direction-Selective Index (DSI)

2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
G. Boschetti ◽  
R. Rosa ◽  
A. Trevisani
Keyword(s):  
Performance Evaluation ◽  
Performance Index ◽  
General Framework ◽  
Dynamic Performance ◽  
Parallel Manipulators ◽  
Parallel Robot ◽  
Performance Indexes ◽  
Definition Of ◽  
Performance Variations

Performance indexes usually provide global evaluations of robot performances mixing their translational and/or rotational capabilities. This paper proposes a definition of performance index, called direction-selective index (DSI), which has been specifically developed for parallel manipulators and can provide uncoupled evaluations of robot translational capabilities along relevant directions. The DSI formulation is first presented within a general framework, highlighting its relationship with traditional manipulability definitions, and then applied to a family of parallel manipulators (4-RUU) of industrial interest. The investigation is both numerical and experimental and allows highlighting the two chief advantages of the proposed DSIs over more conventional manipulability indexes: not only are DSIs more accurate in predicting the workspace regions where manipulators can best perform translational movements along specific directions, but also they allow foreseeing satisfactorily the dynamic performance variations within the workspace, though being purely kinematic indexes. The experiments have been carried out on an instrumented 4-RUU commercial robot.

scholarly journals Smallest Maximum Cable Tension Determination for Cable-Driven Parallel Robots

2021 ◽  
pp. 1-20
Author(s):  
Hussein Hussein ◽  
Joao Cavalcanti Santos ◽  
Jean-Baptiste Izard ◽  
Marc Gouttefarde
Keyword(s):  
Parallel Robots ◽  
Cable Tension

The Correlation between Time and Frequency Dynamic Performance of Control System

2014 ◽  
Vol 628 ◽  
pp. 186-189
Author(s):  
Meng Xiong Zeng ◽  
Jin Feng Zhao ◽  
Wen Ouyang
Keyword(s):  
Control System ◽  
Performance Index ◽  
Dynamic Performance ◽  
Frequency Domain Analysis ◽  
Practical Significance ◽  
Order System ◽  
Time Frequency ◽  
Performance Indexes ◽  
Quantitative Performance ◽  
The Stability

The control system performance requirement was divided into three parts. They were the stability, rapidity and accuracy. The time-frequency domain analysis in the requirements of three performance were measured through quantitative performance index. The mutual restriction of time-frequency performance and system characteristic parameters of normal second order was discussed. The correlation of system time-frequency performance index was established. The relationship between time-frequency performance indexes in standard two order system was extended to higher order system. The mutually constraining and time-frequency correlation between each performance index was obtained by analysis and calculation. The work had been done above had practical significance to reflect the system dynamic performance in different analytical domains.

Thoughts on How Construction Enterprises Improve Performance Management

2013 ◽  
Vol 456 ◽  
pp. 631-635
Author(s):  
Jian Lin Zuo
Keyword(s):  
Performance Evaluation ◽  
Performance Management ◽  
Employee Performance ◽  
Paper Briefly ◽  
Improve Performance ◽  
Index Method ◽  
Construction Enterprises ◽  
Key Performance Index ◽  
Performance Indexes ◽  
Level Performance

This paper briefly introduces several problems of employee performance management in construction enterprises in China, including taking performance evaluation as performance management, being lack of consistent bidirectional communications, one-sided use of results of performance evaluation, malposition of evaluators, psychological disadvantages and barriers of evaluated people and so on; the paper also provides measures including enhancing publicity on purposes and significance of performance management for employees of construction enterprises, utilizing all-round key performance index method to decompose employee-level performance indexes, enhancing communications on performance, and using results of performance evaluation in a scientific way, in order to improve performance management of construction enterprises. This research conclusion can play a role in guiding improvement of performance management of construction enterprises.

scholarly journals Developing An Evaluation Protocol For The Toronto Public Library (TPL) System Through The Application Of A Building Performance Evaluation (BPE) Of A Branch Library To Inform Its Retrofit Strategy

2021 ◽  
Author(s):  
Rosemary Martin
Keyword(s):  
Performance Evaluation ◽  
Thermal Comfort ◽  
Water Consumption ◽  
User Satisfaction ◽  
Public Library ◽  
Performance Evaluations ◽  
Building Performance ◽  
Design Intent ◽  
Evaluation Protocol ◽  
Operational Costs

Buildings play a significant role in our economy and society. Substantial capital is invested in buildings, and they are the locales where a large portion (e.g., work, cultural, religious, social and personal activities) of our lives are conducted. Despite the significant monetary and temporal investments in buildings, building performance evaluations (BPEs) are not standard practice. From BPEs that have been conducted, important findings have been identified. Significant gaps frequently exist between the design intent of buildings and their measured performance (e.g., energy and water consumption) and user satisfaction (e.g., thermal comfort, lighting, noise). Environmental (e.g., resource consumption) and economic drivers (e.g., productivity, operational costs) are spurring the growth of BPEs. A BPE was conducted of the Weston Public Library (WPL) with the intent of informing a retrofit strategy and developing a protocol for conducting BPEs in the Toronto Public Library (TPL) system.

Coordination Performance Evaluation of Supply Logistics in JIT Environment

2011 ◽  
Vol 3 (1) ◽  
pp. 16-28
Author(s):  
Guo Li ◽  
Xiang Zhang ◽  
Zhaohua Wang ◽  
Tao Gao
Keyword(s):  
Supply Chain ◽  
Performance Evaluation ◽  
Customer Service ◽  
Performance Index ◽  
Supply System ◽  
Assembly System ◽  
Analytic Hierarchy ◽  
Supply Logistics ◽  
System Suitability ◽  
Hierarchy Process

In JIT assembly system, any supplier’s postponement of delivery or incorrect delivery quantity will result in the manufacturer’s incapability of assembling on schedule, which will not only damage the interests of other suppliers but also jeopardize the interests of enterprises and reduce the competitiveness of the supply chain. In this article, coordination of the upstream supply logistics from internal and external aspects is taken as the research object. In external supply system, three aspects of cost, quality and time are used to evaluate the coordination of supply logistics in JIT environment. From the internal aspect, reliability, flexibility, responsiveness, customer service and system suitability are selected for the performance evaluation. The eight indexes construct an index system and each performance index is described and analyzed. Finally, Analytic Hierarchy Process is used to evaluate the coordinated performance of supply logistics in JIT environment. An example is provided, which illustrate the method used in this paper is feasible and meaningful.

scholarly journals A stable proportional–proportional integral tracking controller with self-organizing fuzzy-tuned gains for parallel robots

2019 ◽  
Vol 16 (1) ◽  
pp. 172988141881995
Author(s):  
Francisco G Salas ◽  
Jorge Orrante-Sakanassi ◽  
Raymundo Juarez-del-Toro ◽  
Ricardo P Parada
Keyword(s):  
Stability Analysis ◽  
Performance Index ◽  
Closed Loop ◽  
Tracking Error ◽  
Parallel Robots ◽  
Control Loop ◽  
Closed Loop System ◽  
Proportional Integral ◽  
The Stability ◽  
Self Organizing

Parallel robots are nowadays used in many high-precision tasks. The dynamics of parallel robots is naturally more complex than the dynamics of serial robots, due to their kinematic structure composed by closed chains. In addition, their current high-precision applications demand the innovation of more effective and robust motion controllers. This has motivated researchers to propose novel and more robust controllers that can perform the motion control tasks of these manipulators. In this article, a two-loop proportional–proportional integral controller for trajectory tracking control of parallel robots is proposed. In the proposed scheme, the gains of the proportional integral control loop are constant, while the gains of the proportional control loop are online tuned by a novel self-organizing fuzzy algorithm. This algorithm generates a performance index of the overall controller based on the past and the current tracking error. Such a performance index is then used to modify some parameters of fuzzy membership functions, which are part of a fuzzy inference engine. This fuzzy engine receives, in turn, the tracking error as input and produces an increment (positive or negative) to the current gain. The stability analysis of the closed-loop system of the proposed controller applied to the model of a parallel manipulator is carried on, which results in the uniform ultimate boundedness of the solutions of the closed-loop system. Moreover, the stability analysis developed for proportional–proportional integral variable gains schemes is valid not only when using a self-organizing fuzzy algorithm for gain-tuning but also with other gain-tuning algorithms, only providing that the produced gains meet the criterion for boundedness of the solutions. Furthermore, the superior performance of the proposed controller is validated by numerical simulations of its application to the model of a planar three-degree-of-freedom parallel robot. The results of numerical simulations of a proportional integral derivative controller and a fuzzy-tuned proportional derivative controller applied to the model of the robot are also obtained for comparison purposes.

Sorting Through Performance Evaluations: The Influence of Performance Evaluation Reform on Teacher Attrition and Mobility

2020 ◽  
Vol 57 (6) ◽  
pp. 2339-2377 ◽  
Author(s):  
Luis A. Rodriguez ◽  
Walker A. Swain ◽  
Matthew G. Springer
Keyword(s):  
Performance Evaluation ◽  
Teacher Attrition ◽  
Effective Teachers ◽  
Evaluation System ◽  
Race To The Top ◽  
Performance Evaluations ◽  
American Education ◽  
Mobility Patterns ◽  
Low Performing Schools ◽  
School Settings

The federal Race to the Top initiative signified a shift in American education policy whereby accountability efforts moved from the school to the teacher level. Using administrative data from Tennessee, we explore whether evaluation reforms differentially influenced mobility patterns for teachers of varying effectiveness. We find that the rollout of a statewide evaluation system, even without punitive consequences, was associated with increased turnover; however, there was comparably greater retention of more effective teachers, with larger differences in turnover between highly and minimally effective teachers confined to urban districts and low-performing schools. These results imply that states and districts can increase exit rates of low-performing instructors in the absence of automatic dismissals, which is a pattern that our analyses suggest may not generalize beyond urban school settings.

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