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The existence of clearance in joints of positioning mechanism is inevitable and the movements of the real mechanism are deflected from the ideal mechanism due to the clearances. The purpose of this paper is to investigate the effects of clearance on the dynamic characteristics of dual-axis positioning mechanism of a satellite antenna.

The dynamics analysis of dual-axis positioning mechanism with clearance are investigated using a computational approach based on virtual prototyping technology. The contact model in joint clearance is established by using a hybrid nonlinear continuous contact force model and the friction effect is considered by using a modified Coulomb friction model. Then the numerical simulation of dual-axis positioning mechanism with joint clearance is carried out and four case studies are implemented for different clearance sizes.

Clearance leads to degradation of the dynamic performance of the system. The existence of clearance causes impact dynamic loads, and influences the motion accuracy and stability of the dual-axis positioning mechanism. Larger clearance induces higher frequency shakes and larger shake amplitudes, which will deteriorate positioning accuracy.

Providing an effective and practical method to analyze dynamic characteristics of dual-axis positioning mechanism of satellite antenna with joint clearance and describing the dynamic characteristics of the dual-axis positioning system more realistically, which improves the engineering application.

The paper is the basis of mechanism design, precision analysis and robust control system design of dual-axis positioning mechanism of satellite antenna.

Photovoltaic (PV) systems are experiencing exponential growth due to environmental concerns, unlimited and ubiquitous solar energy, and starting-to-make-sense panel costs. Alongside designing more efficient solar panels, installing solar trackers and special circuitry for optimizing power delivery to the load according to a maximum power point tracking (MPPT) algorithm are other ways of increasing efficiency. However, it is critical for any efficiency increase to account for the power consumption of any amendments. Therefore, this paper aims to propose a novel tracker while using MPPT to boost the PV system's actual efficiency accounting for the involved costs.

The proposition is an experimental pneumatic dual-axis solar tracker using light-dependent resistor (LDR) sensors. Due to its embedded energy storage, the pneumatic tracker offers a low duty-cycle operation leading to tracking energy conservation, fewer maintenance needs and scalability potential. While MPPT assures maximum load power delivery, the solar PV's actual delivered power is calculated for the first time, accounting for the solar tracking and MPPT power costs.

The experiments' results show an increase of 37.6% in total and 35.3% in actual power production for the proposed solar tracking system compared to the fixed panel system, with an MPPT efficiency of 90%. Thus, the pneumatic tracking system offers low tracking-energy consumption and good actual power efficiency. Also, the newly proposed pneumatic stimulant can significantly simplify the tracking mechanism and benefit from several advantages that come along with it.

To the best of the authors’ knowledge, this work proposes, for the first time, a single-motor pneumatic dual-axis tracker with less implementation cost, less frequent operation switching and scalability potential, to be developed in future works. Also, the pneumatic proposal delivers high actual power efficiency for the first time to be addressed.

THE SYSTEM is a joint design and manufacturing responsibility of Marconi‐Elliott Avionic Systems Ltd, a GEC‐Marconi Electronics company, and SFENA (Société Française d'Equipements pour la Navigation Aérienne).

This paper allows more accurate estimation of the economy in investing in PV electrification for buildings, especially for Gulf Cooperation Council Countries (GCCC) where they have nearly similar climate and building structure. The actual solar electricity yield from this building is used to make empirical modelling.

The accurate automated daily-recorded solar electricity from 8.64 kW solar PV on a rooftop of Sadeem Building at Awali, Bahrain, was modelled to polynomial equations of order of 6. The effect of the tilt (β) and azimuth (Ψ) angle of PV panels for smart and sustainable buildings is studied.

The correlation of each set of polynomial equation (R²) is listed and had reached a highest value of 0.9792 (for order of 6) with lowest value of 0.1853 (for order of 1). The model may be also applied to the GCCC. The results show that each kW of PV will have a solar electricity yield, on average, of 4.1 kWh. It also shows that the tilt angle has little influence on the solar electricity yield (less than 10%) when the tilt angle changed from 26° to 0° or from 26° to 50°. The influence of the azimuth angle is found to be more than 50% in changing Ψ from 90° to 180°.

The model may not be restricted to Bahrain but applies – to a certain extent – to GCCC (six countries) and to other countries having buildings with similar roof design and at latitude close to the latitude of Bahrain.

The model enables developers and investors to estimate, with high accuracy, the solar electricity provided from a building if PV panels are to be installed on its rooftop (or facade) at different tilt (β) and azimuth (Ψ) angle for smart and sustainable buildings.

Empirically finding out how much each kW of solar PV integrated to the building will produce solar energy electricity (in kWh), that is, 1 kW of PV yield, on average, 4.1 kWh.

Establishing empirical models to evaluate the outcome of each installed kW of PV panels. Each 1 kW installation of PV panels is 4.0 kWh/day, on average. This is less than what commercial companies claim for this region, that is, 1 kW produces 5.5 kWh/ day – which affects the estimated economic outcome of PV projects.

This paper aims to propose a united kinematic calibration method for a dual-machine system in automatic drilling and riveting. The method takes both absolute and relative pose accuracy into account, which will largely influence the machining accuracy of the dual-machine system and assembly quality.

A comprehensive kinematic model of the dual-machine system is established by the superposition of sub-models with pose constraints, which involves base frame parameters, kinematic parameters and tool frame parameters. Based on the kinematic model and the actual pose error data measured by a laser tracker, the parameters of coordinated machines are identified by the Levenberg–Marquardt method as a multi-objective nonlinear optimization problem. The identified parameters of the coordinated machines will be used in the control system.

A new calibration method for the dual-machine system is developed, including a comprehensive kinematic model and an efficient parameter identification method. The experiment results show that with the proposed method, the pose accuracy of the dual-machine system was remarkably improved, especially the relative position and orientation errors.

This method has been used in an aircraft assembly project. The calibrated dual-machine system shows a good performance on system coordination and machining accuracy.

This paper proposes a new method with high accuracy and efficiency for the dual-machine system calibration. The research can be extended to multi-machine and multi-robot fields to improve the system precision.

The purpose of this paper is to develop a dual peg-in-hole insertion strategy. Dual peg-in-hole insertion is the most common task in manufacturing. Most of the previous work develop the insertion strategy in a two- or three-dimensional space, in which they suppose the initial yaw angle is zero and only concern the roll and pitch angles. However, in some case, the yaw angle could not be ignored due to the pose uncertainty of the peg on the gripper. Therefore, there is a need to design the insertion strategy in a higher-dimensional configuration space.

In this paper, the authors handle the insertion problem by converting it into several sub-problems based on the attractive region formed by the constraints. The existence of the attractive region in the high-dimensional configuration space is first discussed. Then, the construction of the high-dimensional attractive region with its sub-attractive region in the low-dimensional space is proposed. Therefore, the robotic insertion strategy can be designed in the subspace to eliminate some uncertainties between the dual pegs and dual holes.

Dual peg-in-hole insertion is realized without using of force sensors. The proposed strategy is also used to demonstrate the precision dual peg-in-hole insertion, where the clearance between the dual-peg and dual-hole is about 0.02 mm.

The sensor-less insertion strategy will not increase the cost of the assembly system and also can be used in the dual peg-in-hole insertion.

The theoretical and experimental analyses for dual peg-in-hole insertion are proposed without using of force sensor.

This paper aims to present an efficient design approach for the micro electromechanical systems (MEMS) accelerometers considering design parameters affecting the long-term reliability of these inertial sensors in comparison to traditional iterative microfabrication and experimental characterization approach.

A dual-axis capacitive MEMS accelerometer design is presented considering the microfabrication process constraints of the foundry process. The performance of the MEMS accelerometer is analyzed through finite element method– based simulations considering main design parameters affecting the long-term reliability. The effect of microfabrication process induced residual stress, operating pressure variations in the range of 10 mTorr to atmospheric pressure, thermal variations in the operating temperature range of −40°C to 100°C and impulsive input acceleration at different input frequency values is presented in detail.

The effect of residual stress is negligible on performance of the MEMS accelerometer due to efficient design of mechanical suspension beams. The effect of operating temperature and pressure variations is negligible on energy loss factor. The thermal strain at high temperature causes the sensing plates to deform out of plane. The input dynamic acceleration range is 34 g at room temperature, which decreases with operating temperature variations. At low frequency input acceleration, the input acts as a quasi-static load, whereas at high frequency, it acts as a dynamic load for the MEMS accelerometer.

In comparison with the traditional MEMS accelerometer design approaches, the proposed design approach focuses on the analysis of critical design parameters that affect the long-term reliability of MEMS accelerometer.

Measurement-while-drilling (MWD) system has been used to provide trajectory and inclination parameters of the oil and gas well. Fluxgate magnetometer is a traditional choice for one MWD system; however, it cannot obtain effective trajectory parameters in nonmagnetic environments. Fiber-optic-gyroscope (FOG) inclinometer system is a favorable substitute of fluxgate magnetometer, which can avoid the flaws associated with magnetic monitoring devices. However, there are some limitations and increasing surveying errors in this system under high impact conditions. This paper aims to overcome these imperfections of the FOG inclinometer system.

To overcome the imperfections, filtering algorithms are used to improve the precision of the equipment. The authors compare the low-pass filtering algorithm with the wavelet de-noising algorithm applied to real experimental data. Quantitative comparison of the error between the true and processed signal revealed that the wavelet de-noising method outperformed the low-pass filtering method. To achieve optimal positioning effects, the wavelet de-noising algorithm is finally used to inhibit the interference caused by the impact.

The experimental results show that the method proposed can ensure the azimuth accuracy lower than ±2 degrees and the inclination accuracy lower than ± 0.15 degrees under the condition of interval impact. The method proposed can overcome the interference generated by the impact in the well, which makes the instrument suitable for the measurement of small-diameter casing well.

After conducting the wavelet threshold filtering on the raw data of accelerometers, the noise generated by the impact is successfully suppressed, which is expected to meet the special requirement of the down-hole survey environment.

Identifying the state of alignment, when there is misalignment, and the path to achieve alignment are of central importance to decision makers today. This paper seeks to offer decision makers some actionable guidance in narrowing the search for possible solution methodologies and to develop a generalized decision alignment framework that can be applied to real decision problems.

Alignment is viewed as a goal of decision makers and the correct matching of decision and action is essential to achieving consistently high performance. Drawing on parallels with the duality problem in linear programming, decision alignment is defined. The decision alignment framework is theoretically developed using examples from a diverse application set, including quantitative research, decision making, education, and e‐commerce.

The evidence shows that good research conforms to the decision alignment framework and poor research violates it. Similarly, good decisions conform to the decision alignment framework and poor decisions violate it. The decision alignment framework guides decision makers in constraining and redefining problems to optimize outcome performance, and shows the importance of addressing the dual problem of learning and understanding the phenomena.

The theoretical foundation developed can be used to promote future research in decision alignment. By providing a theoretically derived framework, rich opportunities for empirical testing are offered. Researchers are also given guidance on how alignment research can be conducted.

The examples presented highlight the prescriptive, communicative, and descriptive value of the decision alignment framework. Practitioners are provided with examples for using the decision alignment framework to build toolboxes of approaches that can be aligned to a characterization of real‐world decision problems to improve performance.

The introduction of a decision alignment framework is a significant contribution to the management decision literature. By introducing a decision alignment framework, the rather ambiguous term alignment is precisely defined as the matching of decision problem characterization (primal problem) with the approach possibility set (dual problem).