In this research, a novel polarization reconfigurable fractal antenna with high gain is proposed for wideband applications. This antenna consists of a Koch curve based hexagonal ring patch, two Positive-Intrinsic-Negative (PIN) diodes, and partial ground. The patch is positioned on a Rogers RT/Duroid 5880 substrate (ϵr = 2.2) with overall dimensions 33 × 30 × 1.6 mm3. It has three frequency bands with three different cases i.e., case I, 3–7.91 (90%); case II, 3–7.73 (88.16%); and case III, 3.54–6.7 GHz (61.7%). As a result, the proposed antenna’s impedance bandwidth (IBW) offers constant wideband coverage ranging from 3–7.91 GHz (90%). The axial ratio bandwidth (ARBW) is below 3 dB over 3.6–6.9 (62.86%) and 3.33–7.14 GHz (72.78%) for LHCP (Case I) and RHCP modes (Case II), respectively. The value for LP mode (Case III) is 3.54–6.7 GHz (61.7%). A peak realized gains of 4.75, 5.07, and 3.8 dBi are achieved at 6.2, 6.3, and 6 GHz for Case I, Case II, and Case III, respectively. Both linear and circular polarization prototype was developed and the performance was verified through measurements. The design confirms good polarization-reconfigurable characteristics within the band of 3.91 – 7.91 GHz.

The cable-driven parallel mechanism (CDPM) is known as an interesting application in industry to pick and place objects owing to its advantages such as large workspaces. In addition to the advantages of this mechanism, there are some challenges to improving performance by considering constraints in different components, such as the behavior of cables, shape, size of the end effector and base, and model of pulleys and actuators. Moreover, the impact of online geometry reconfiguration must be analyzed. This paper demonstrates the impact of these constraints on the performance of reconfigurable CDPM. The methodology is based on the systematic review and meta-analysis guidelines to report the results. The databases used to find the papers are extracted from Scopus and Google Scholar, using related keywords. As a result, the impact of physical constraints on system performance is discussed. A total of 90 and 37 articles are selected, respectively. After removing duplicates and unrelated papers, 88 studies that met the inclusion criteria are selected for review. Even when considering the physical constraints in modeling the mechanism, simplifications in designing a model for the reconfigurable CDPM generate errors. There is a gap in designing high-performance controllers to track desired trajectories while reconfiguring the geometry, and the satisfaction of physical constraints needs to be satisfied. In conclusion, this review presents several constraints in designing a controller to track desired trajectories and improve performance in future work. This paper presents an integrated controller architecture that includes physical constraints and predictive control.

Productivity can be increased by manipulators tracking the desired trajectory with some constraints. Humans as moving obstacles in a shared workspace are one of the most challenging problems for cable-driven parallel mechanisms (CDPMs) that are considered in this research. One of the essential primary issues in CDPM is collision avoidance among cables and humans in the shared workspace. This paper presents a model and simulation of a reconfigurable, fully constrained CDPM enabling detection and avoidance of cable–human collision. In this method, unlike conventional CDPMs where the attachment points are fixed, the attachment points on the rails can be moved (up and down on their rails), and then the geometric configuration is adapted. Karush–Kuhn–Tucker method is proposed, which focuses on estimating the shortest distance among moving obstacles (human limbs) and all cables. When cable and limbs are close to colliding, the new idea of reconfiguration is presented by moving the cable’s attachment point on the rail to increase the distance between the cables and human limbs while they are both moving. Also, the trajectory of the end effector remains unchanged. Some simulation results of reconfiguration theory as a new approach are shown for the eight-cable-driven parallel manipulator, including the workspace boundary variation. The proposed method could find a collision-free predefined path, according to the simulation results.

The purpose of this study aims to explore the relationships between business portfolio reconfiguration and firm performance in developing countries as well as the moderating roles played by organizational slack, capabilities and ownership structure. By using the perspectives of dynamic capabilities, resources-based view and social network, this study proposes that there is a U-shaped relationship between business portfolio reconfiguration and firm performance. Furthermore, while R&D capability, marketing capability and foreign ownership are expected to positively moderate this U-shaped relationship, organizational slack, state and domestic ownership may potentially make this U-shaped relationship less pronounced. We draw our observations from Shanghai and Shenzhen Stock Exchanges in China from 2008 to 2017, and obtain 26,151 firm-year observations, which are consisted of 3,508 publicly traded companies. The results generally support our hypotheses, and some theoretical and practical implications are extracted from this study.

Aileron to Rudder Interconnect (ARI) gain is implemented on most fighter aircraft, primarily to reduce the side slip produced due to adverse yaw from pilot lateral control stick input and to improve the turn rate response. A systematic and non-iterative design procedure for ARI gain is proposed herein based on the evaluation of a transfer function magnitude at the aircraft roll mode frequency. The simplicity of the proposed method makes it useful for real-time flight control law reconfiguration in situations where the aileron control authority is diminished due to damage. This is demonstrated by a simulation example considering an aileron surface damage scenario.

One of the aims of systems engineering is to develop systems with a number of pre-defined configurations, in order to operate effectively and efficiently in different contexts and environments. Early in the design phase, system reconfiguration allows to propose and optimize these configurations. With regard to the literature review and industrial observation, pre-defining the standard configurations without relying on hints from end users has been raised as a major difficulty within the industry. In this paper, we propose a reconfiguration framework which considers data collected from the use phase in order to generate valid and optimized configurations with regard to stakeholders needs.

This paper develops a controller for position tracking of a new ball wheel drive mechanism for a robust omnidirectional wheeled mobile platform, an adaptive controller with physical parameter estimation. This platform, integrated with a manipulator, is designed for use in highway maintenance and construction, which is a generally unstructured and congested environment. The proposed ball wheel mechanism can move in all directions on the plane, instantaneously and isotropically. Reconfiguration of the redundant drive system of the ball wheel mechanism is accomplished by altering the contact pressure between the drive wheels and the sphere based on platform heading direction. The system redundancy is resolved through a Weighted Optimal Torque Distribution method allowing for smooth reconfiguration. Finally, experimental and simulation results demonstrate the effectiveness of the approach.

Smart devices used in continuous system, benefit from the addition of microelectronics and software that runs inside the device to perform control and diagnostic functions. Very small components, such as inputs/outputs blocks and overload relays, are too small to integrate data processing for technical-economic reason. However, it's possible to develop embedded intelligence and control for the smallest factory floor devices. In the paper, a generic model of smart equipment with reconfiguration functions is proposed. The interest of this functional model is that it can be used for smart devices but it can also be developed in modules for the nearest possible of the inputs and outputs in manufacturing equipment. This solution is economic for a great number of applications because it allows one to realise modular design and to standardise part of system in order to re-use it.