Practical Implementation Aspects of Large-Scale Optimal Control Solvers

2017 ◽  
pp. 277-306
Author(s):  
Thomas J. Böhme ◽  
Benjamin Frank
Keyword(s):  
Optimal Control ◽  
Large Scale ◽  
Practical Implementation ◽  
Implementation Aspects

Implementation aspects of agile methods in large organizations

e-mentor ◽  
2021 ◽  
Vol 90 (3) ◽  
pp. 64-72
Author(s):  
Robert Pawlak ◽  
Keyword(s):  
Best Practices ◽  
Large Scale ◽  
Success Factors ◽  
Implementation Process ◽  
Business Practice ◽  
Organization Culture ◽  
Agile Methods ◽  
Implementation Challenges ◽  
Depth Analysis ◽  
Implementation Aspects

The aim of this article is to analyze the challenges and success factors on organizations’ path to agile transformation, as frequently discussed in the literature and encountered in business practice. The research conducted proved that large-scale agile transformations require a dedicated approach with set of tools and best practices in place. The implementation challenges and barriers have been categorized into method-, organization-, culture- and technology-oriented groups. As a result of an in-depth analysis carried on for the purpose of this paper, a dedicated methodology of agile transformation has been proposed to ease the implementation process.

Two-Level Robust Optimal Control of Large-Scale Nonlinear Systems

2015 ◽  
Vol 9 (1) ◽  
pp. 242-251 ◽  
Author(s):  
Nasser Sadati ◽  
Mehdi Rahmani ◽  
Mehrdad Saif
Keyword(s):  
Optimal Control ◽  
Nonlinear Systems ◽  
Large Scale ◽  
Robust Optimal Control

Maximum load determination of nonholonomic mobile manipulator using hierarchical optimal control

Robotica ◽  
2011 ◽  
Vol 30 (1) ◽  
pp. 53-65 ◽  
Author(s):  
M. H. Korayem ◽  
V. Azimirad ◽  
H. Vatanjou ◽  
A. H. Korayem
Keyword(s):  
Optimal Control ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
Maximum Load ◽  
Mobile Manipulator ◽  
Interaction Terms ◽  
Different Types ◽  
Interaction Variables ◽  
Maximum Allowable Dynamic Load

SUMMARYThis paper presents a new method using hierarchical optimal control for path planning and calculating maximum allowable dynamic load (MADL) of wheeled mobile manipulator (WMM). This method is useful for high degrees of freedom WMMs. First, the overall system is decoupled to a set of subsystems, and then, hierarchical optimal control is applied on them. The presented algorithm is a two-level hierarchical algorithm. In the first level, interaction terms between subsystems are fixed, and in the second level, the optimization problem for subsystems is solved. The results of second level are used for calculating new estimations of interaction variables in the first level. For calculating MADL, the load on the end effector is increased until actuators get into saturation. Given a large-scale robot, we show how the presenting in distributed hierarchy in optimal control helps to find MADL fast. Also, it enables us to treat with complicated cost functions that are generated by obstacle avoidance terms. The effectiveness of this approach on simulation case studies for different types of WMMs as well as an experiment for a mobile manipulator called Scout is shown.

Large-Scale Evaluation of Constrained Bearing Elements Made of Thermosetting Polyester Resin and Polyester Fabric Reinforcement

2006 ◽  
Vol 128 (4) ◽  
pp. 681-696 ◽  
Author(s):  
P. Samyn ◽  
W. Van Paepegem ◽  
J. S. Leendertz ◽  
A. Gerber ◽  
L. Van Schepdael ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Large Scale ◽  
Elastic Recovery ◽  
Small Scale ◽  
Practical Implementation ◽  
Fiber Failure ◽  
Stick Slip ◽  
Composite Surface ◽  
Pull Out ◽  
Stable Sliding

Polymer composites are increasingly used as sliding materials for high-loaded bearings, however, their tribological characteristics are most commonly determined from small-scale laboratory tests. The static strength and dynamic coefficients of friction for polyester/polyester composite elements are presently studied on large-scale test equipment for determination of its bearing capacity and failure mechanisms under overload conditions. Original test samples have a diameter of 250 mm and thickness of 40 mm, corresponding to the practical implementation in the sliding surfaces of a ball-joint, and are tested at various scales for simulation of edge effects and repeatability of test results. Static tests reveal complete elastic recovery after loading to 120 MPa, plastic deformation after loading at 150 MPa and overload at 200 MPa. This makes present composite favorable for use under high loads, compared to, e.g., glass-fibre reinforced materials. Sliding tests indicate stick-slip for pure bulk composites and more stable sliding when PTFE lubricants are added. Dynamic overload occurs above 120 MPa due to an expansion of the nonconstrained top surface. A molybdenum-disulphide coating on the steel counterface is an effective lubricant for lower dynamic friction, as it favorably impregnates the composite sliding surface, while it is not effective at high loads as the coating is removed after sliding and high initial static friction is observed. Also a zinc phosphate thermoplastic coating cannot be applied to the counterface as it adheres strongly to the composite surface with consequently high initial friction and coating wear. Most stable sliding is observed against steel counterfaces, with progressive formation of a lubricating transfer film at higher loads due to exposure of PTFE lubricant. Composite wear mechanisms are mainly governed by thermal degradation of the thermosetting matrix (max. 162°C) with shear and particle detachment by the brittle nature of polyester rather than plastic deformation. The formation of a sliding film protects against fiber failure up to 150 MPa, while overload results in interlaminar shear, debonding, and ductile fiber pull-out.

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