Desired Orientation Research Articles

A Lyapunov based posture controller for a differential drive mobile robot

Driving a vehicle to a desired position and orientation is one of the most important problems that should be solved in most navigation systems. This paper describes a new complete design and hardware implementation of a two-level controller that will enable a differential drive mobile robot to reach any desired posture starting from any initial position. The first or low-level controller consists of a set of two proportional–integral–derivative (PID) controllers, running on an embedded system on board of the robot. These controllers provide the required voltages to the motors to make the left and right wheels of the robot rotate with the angular speeds computed by the second or high-level controller, running on a stationary PC system. This second controller is based on the Lyapunov stability theorem to derive two control laws for the kinematic model, used to transform the linear and angular speeds of the unicycle model in terms of left and right rotational speeds, required by the motors. As will be shown later, this architecture provides a very flexible way not only to tune the main controller parameters but also to get access and record all the system states.

Explorations of the holonomy of a rolling sphere

Consider a rigid body rolling with one point in contact with a fixed surface. Now suppose that the instantaneous point of contact traces out a closed path. As a demonstration of a phenomenon known as holonomy, the body will typically not return to its original orientation. The simplest demonstration of this phenomenon in rigid body dynamics occurs in the motion of a rolling sphere and finds application to path planning and reorientation of spherical robots. Motivated by earlier works of Bryant and Johnson, we establish expressions for the change in orientation of a rolling sphere after completing a rectangular path. We use numerical methods to show that all possible changes in orientation are possible using a single rectangular path. Based on the Euler angle parameterization of a rotation, we develop a more intuitive method to achieve a desired orientation using three rectangular paths. With regards to applications, the paths we discuss can be employed to achieve any desired reorientation of a spherical robot.

Asexual individuals report high preferences for femininity in male and female faces

ABSTRACT Preferences for sexual dimorphism in male and female faces can vary based on the viewers’ gender, sexual orientation, and intensity of sexual desire. Asexual individuals, who experience little to no sexual attraction, may display different preferences for sexual dimorphism than has been observed in allosexual samples. Researchers have hypothesised that gender conformity may likewise impact preferences for sexual dimorphism. Participants (N = 182) recruited from an online asexual community provided demographic information and responded to measures of romantic attraction, sexual attraction, and conformity with male and female gender norms before they indicated their preference for male and female faces that were digitally altered to be more or less sexually dimorphic. Regardless of gender, asexual participants displayed a high preference for femininity in male and female faces. Preferences for sexual dimorphism displayed complex, and inconsistent associations with reported romantic and sexual attraction, and with conformity to feminine gender norms. This is the first report of preferences for facial sexual dimorphism and assessment of the role of gender conformity in an asexual population. This research adds to our understanding of the role of sexual attraction in predicting preferences for sexual dimorphism in faces.

Fast Convergent Ali Baba and Forty Thieves Algorithm for Inverse Kinematic Solution of 7-DOF Robotic Manipulator

Inverse kinematics is a crucial topic in robotics, enabling robots to calculate the joint angles required to achieve the desired end effector position and orientation. Solving the inverse kinematics problem quickly with high accuracy is vital for robot manipulators. If sufficient speed is provided, the real-time motion planning task of robot manipulators can be achieved. Real-time motion planning of complex robot manipulators is not possible with classical mathematical methods. Overcoming this problem will provide many benefits in the design and control of robot manipulators. In contemporary research, metaheuristic approaches have become widely employed for addressing the inverse kinematics problem. This investigation utilizes the efficient and simple Ali Baba and the Forty Thieves (AFT) algorithm to resolve the inverse kinematics problem. To increase convergence speed of AFT, a parameter has been used in early iterations of the algorithm to prevent thieves from randomly searching within the search area to find Ali Baba when they realized they had been deceived. Additionally, an approach has been proposed regarding the accuracy of the information brought by the Marjaneh. Finally, the inverse kinematics solution of the 7-DOF robot manipulator was carried out comparatively.

Application of the Obstacle Vector Field Method for Trajectory Planning of a Planar Manipulator in Simulated Microgravity

Abstract Capture and removal of large space debris is needed to prevent the growth of the debris population in low Earth orbit. Capture of a non-cooperative object by a manipulator mounted on a chaser satellite requires collision-free trajectory of the manipulator. The obstacle vector field (OVF) method allows to solve the trajectory planning problem in difficult scenarios. The OVF method is based on a vector field that surrounds the obstacles and generates virtual forces that drive the manipulator around the obstacles. The original formulation of the OVF method allows to obtain the desired position of the gripper, but not the desired orientation. To perform the grasping manoeuvre, the gripper has to be positioned in a specific point and aligned with the grasping interface. In this paper, we propose a modification to the OVF method that allows to obtain the desired position and orientation of the gripper. Moreover, we investigate the practical applicability of the OVF method. The OVF method is demonstrated in experiments performed on a planar air-bearing microgravity simulator. The presented results prove that the OVF method can be applied for a real system operating in simulated microgravity conditions.

A way to sustainable development of a slum rehabilitation residential project through building information model

Sustainable development in the construction industry majorly relies on energy consumption and CO2 emissions. It has been well proven that building contribute to majority of energy consumption. Also, orienting the building as per sun path, providing insulation to external elements of the building helps in reducing the energy consumption of a building. But desired orientation and providing additional insulation may not be always possible especially to a slum rehabilitation project. Thus, choosing appropriate materials especially external wall material which is crucial for heat gain inside the building is important. Considering a case of Slum Rehabilitation residential project situated in Pune city, G+2 model is created using Building Information modelling tools (Revit, Autodesk Insight) with actual material usage on the existing project based on survey. This study focuses on reducing the energy consumption by choosing appropriate wall material considering cost, CO2 emission, and energy analysis. The matrix providing energy consumption, cost and CO2 emission for the considered wall alternatives will help to choose optimum option for wall having benefits to a project like lesser energy consumption, cost and lower CO2emissions. The outcome will help the developers and slum rehabilitation authority to reduce the energy usage and thus CO2 emissions and cost to deliver energy flexible and low carbon building at optimum cost.

The impact of corporate performance on innovation management: Empirical evidence from emerging Asian economies

Innovation is the key to survive, adapt, and succeed in modern markets, which are increasingly exposed to and impacted by the transformation in progress, especially from a technological point of view, and even more so as a result of the COVID-19 pandemic. However, the propensity to innovate is not only a desirable orientation of enterprises, but also a business process that absorbs relevant resources. In this vein, this study aims to understand if there is a connection, in the form of a direct and positive effect, between corporate performance and innovation, measured in terms of both expenses and intensity, with a specific focus on the Asian region (China, Hong Kong, Malaysia, Singapore, South Korea, and Thailand). While a direct relationship seems to exist when assessed by financial indicators (Tobin's Q), the same cannot be completely proved in relation to accounting ones (return on equity). Related implications, at the theoretical and practical level, are then provided, especially in regard to the potential contribution (and consequent appreciation) of intellectual capital.

Formation mechanism of aluminum and its carbides under wobbling laser melting injection with carbon nanotubes-SiC hybrid particles

The softening problem of fusion zone (FZ) impede the widespread application of wobbling laser welding (WLW) which plays an essential role in aluminum alloy welding. The introduction of carbon nano tubes (CNTs) and SiC particles (SiCp) has the potential to alleviate this problem, whereas the mechanism of aluminum solidification and carbides synthesis under wobbling laser with multiple reinforcers is still unknown. Accordingly, CNTs-SiCp reinforced aluminum FZ is fabricated by wobbling laser melting injection (WLMI) for the first time. The numerical simulation of WLW and WLMI is incorporated in microstructure characterization, kinetic-thermodynamic calculation is innovatively carried out to determine the critical synthesis condition of carbides. The new insights into the nucleation/growth and orientations principle of aluminum with its carbides are demonstrated comprehensively. Firstly, the process of WLMI makes preferred growth of Al in FZ more diversified than that under WLW due to the undulate liquid-mushy interface. Secondly, carbides of Al4C3 and Al4SiC4 can exhibit a coupled growth in FZ edge due to high frequency and large amplitude of temperature fluctuation, rather than that have an independent growth in FZ center with relatively stable temperature. Thirdly, the coherent orientation relationships (ORs) that <0001>Al4C3//<0001>Al4SiC4 and <0001>Al4C3//<100>Al is preferred to be formed under oscillating heat-flow field of WLMI. Finally, the desired orientation of Al, Al4C3 and Al4SiC4 with fine grain can be gained in FZ, its strength has even exceeded base metal by more than 10%. This paper can be regarded as a breakthrough in strengthening FZ under WLW, by WLMI with CNTs-SiCp hybrid particles, and provide a theoretical guidance of microstructure and property optimization.

Profiles and developmental pathways of beginning teachers' intrinsic orientations and their associations with effective teaching behaviour

Prior research has highlighted the importance of intrinsic motivational-affective characteristics in empowering teachers to excel amidst professional complexities. This study sought to move beyond the prevailing focus on cross-sectional relationships between individual motivational-affective factors and specific aspects of effective teaching, seeking to understand their cumulative significance in shaping the longitudinal development of effective teaching. By proposing teachers' intrinsic motivational-affective orientations as profile indicators, this study profiles teachers during their initial two career years. Through surveying and observing 274 Dutch beginning teachers over three data collection waves, the results of latent profile and transition analyses identified two distinct profiles and four developmental pathways. A favorable profile exhibits positive correlations with stimulating learning climate and differentiated instruction. Moreover, the desirable pathways contribute to the development of differentiated instruction, offering valuable insights into sustainable professional growth for beginning teachers. Educational relevant statementThe present study holds significant educational relevance as it contributes to the theoretical understanding of teacher motivation, identity, and professional development. By identifying distinct profiles and developmental pathways of beginning teachers' intrinsic motivational-affective orientations, the study offers valuable guidance for targeted support strategies in teacher education and professional development programs. Furthermore, the recognition of non-linear associations between teachers' intrinsic orientations and specific effective teaching behaviours highlights the importance of cultivating desirable orientations to enhance teachers' capacity for establishing inclusive and stimulating learning environments. In general, this study carries practical implications for school leadership and educational institutions, offering avenues to foster positive and sustainable learning experiences for both teachers and students.

Hak Asasi Manusia; Studi Komparatif antara Orientasi Kebebasan Manusia Perspektif Buddhisme dan Islam

Human Rights is a discourse that has several orientations on issues around humanity. One of the elements in the formulation and ratification of human rights in this law is to guarantee that every individual has freedom of will and action in their lives. However, the desired orientation of freedom in this formulation experiences several problems, including confusion in understanding the meaning of freedom itself, many of the world's scientists provide a variety of different perspectives on the meaning of the discourse. In addition, the aridity of religious elements is also felt in the formulation of human rights, so it is necessary to understand aspects of human freedom from several perspectives, such as Islam and Buddhism, two religions that have a concept of humanity and a philosophy of several elements related to this concept. Islam and Buddhism have two concepts related to the freedom orientation above, Insan Kaamil in Islam and Bodhisattva in Buddhism. These two things will be observed with a theological approach and comparative method so that basic conclusions will be obtained on the concept of man and freedom in the two religions and an analysis of the relationship between the concepts of freedom in Islam and Buddhism.

Desirable Entrepreneurial Orientation as a Mediator between Entrepreneurial Attitude and Entrepreneurial Self-efficacy for Business Performance Efficiency

Desirable Entrepreneurial Orientation as a Mediator between Entrepreneurial Attitude and Entrepreneurial Self-efficacy for Business Performance Efficiency

Inertial Stable Platforms for Precision Pointing of Optical Systems in Aerospace Applications

Both airborne and space-based high-energy laser weapon systems present interesting challenges for precision line-of-sight control. Sub-microradian to microradian pointing accuracies are required against dynamic targets. In addition, “absolute” pointing and accurate inertial angular rate measurement are required to support mission requirements. This paper addresses these unique directed-energy weapon (DEW) precision-pointing requirements and their associated implementation alternatives in the context of strapdown and stable platform inertial reference technologies. The contributions of this paper consider the broader issues of DEW requirement drivers, integration of the stabilization system with the rest of the optical system, and design tradeoffs between stable platform and strapdown stabilization mechanizations. Both types of mechanisms are mounted to the gimbal of an imaging system using gryo sensors (gyros) and accelerometers to maintain a desired orientation in inertial space independent of the craft motion. Although both can include an optical reference that propagates through the optical path for optical alignment and jitter control, only in the stable platform is the optical reference stabilized. When combined on the same platform with a stabilized inertial measurement system and closed-loop stabilization with the optical reference, the mechanism becomes a stabilized inertial reference unit, which provides a stabilized optical reference to the electro-optical/laser pointing and jitter control systems.

All-optical ultrafast spin rotation for relativistic charged particle beams

An all-optical method of ultrafast spin rotation is put forward to precisely manipulate the polarization of relativistic charged particle beams of leptons or ions. Laser-driven dense ultrashort beams are manipulated via single-shot interaction with a copropagating temporally asymmetric laser pulse of moderate intensity. Using semiclassical numerical simulations, we show that the initial polarization of a lepton (proton) beam can be rotated to any desired orientation by a flexible control over the phase retardation between the spin precession and the momentum oscillation in a temporally asymmetrical (e.g., half-cycle terahertz or frequency-chirped) laser field. In particular, spin ultrafast rotation from the common transverse to the more valuable longitudinal polarization is feasible in a picosecond scale or less. Moreover, the beam quality, in terms of energy and angular divergence, is improved in the rotation process. This method has potential applications in various areas demanding ultrafast spin manipulation, like laser-plasma, laser-nuclear, and high-energy physics.

Inverse Kinematics for Serial Robot Manipulators by Particle Swarm Optimization and POSIX Threads Implementation

Inverse kinematics is a fundamental problem in manipulator robotics: a set of joint angles must be calculated so that the robot arm can be manipulated to the corresponding desired end effector position and orientation (also known as “pose”). Traditional solution techniques include analytical kinematics solvers, which provide the closed-form expressions for the joint positions as functions of the end-effector pose. When analytical inverse kinematics solvers are not possible due to the manipulator structure, numerical methods such as Newton–Raphson or Jacobian inverse can be used to achieve the task, but at a much slower speed due, to the iterative nature of the computation. Recent swarm intelligence technology has also contributed to manipulator inverse kinematics solutions. In this paper, the use of the Particle Swarm Optimization (PSO) approach in solving the inverse kinematics problem is investigated for the general serial robotic manipulators. Many of the reviewed robotic manipulator inverse kinematics solvers using swarm intelligence only deal with end effector position and not its orientation. Our PSO approach provides the convergence of a complete end-effector pose and will be demonstrated using the Baxter Research Robot, which has two seven-joint arms, although the method is applicable to any general serial robotic manipulator. For computational efficiency, the inverse kinematic calculations were implemented in parallel using Portable Operating Interface (POSIX) threads to take advantage of the independent swarm particle dynamics.

Exploring Inclusion Complex of an Antithyroid Drug (PTU) with α-Cyclodextrin for Innovative Applications by Physicochemical Approach Optimized by Molecular Docking

Herein, we aim to form the inclusion complex (IC) of an antithyroid drug 6-propyl-2-thiouracil (PTU) with α-cyclodextrin (α-CD) and to analyse its aqueous solubility, photostability, binding with Calf thymus DNA (CT-DNA), antibacterial and cytotoxic activities. The PTU-α-CD complex was synthesized by following the co-precipitation method with a molar ratio of 1:1. The formed complex was characterized by employing several spectroscopic techniques such as nuclear magnetic resonance (1H NMR), fourier transform infrared (FTIR), differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA), powder XRD and scanning electron microscopy (SEM) indicated the successful encapsulation of drug PTU into the nano cage of α-CD. The enhancement of thermal stability of PTU after complexation was shown by TGA and DSC analysis. Job’s plot confirmed the 1:1 M ratio of guest (PTU) and host (α-CD) during the formation of IC and the molecular association constant as predicted between PTU and α-CD using UV–vis titration method was found to be 3297.57 ± 0.15 M−1. The most desired orientation of the PTU molecule within the non-polar binding pocket of α-CD cavity was speculated by molecular modelling study. The PTU-α-CD complex showed better in vitro antimicrobial activity results as compared to pure drug PTU. The aqueous solubility and photostability of PTU were greatly improved owing to the formation of the PTU-α-CD complex as shown using UV–vis spectroscopy. The PTU-α-CD complex (IC50 = 2.12 µM) also displayed noteworthy in vitro cytotoxic activity than pure PTU (IC50 = 6.44 µM) towards human kidney cancer cell line (ACHN) whereas (IC50 = 3.63 µM) and (IC50 = 2.09 µM) for PTU-α-CD and drug respectively in a normal kidney cell line (HEK-293). This research also predicts the release of PTU in presence of CT-DNA without any chemical alteration. Finally, these outcomes disclose that the complexation of PTU with α-CD could enhance the stability of PTU and display various applications associated with it.

Distributed bearing-based formation maneuver control of fixed-wing UAVs by finite-time orientation estimation

This paper investigates the bearing-based formation maneuver control problem for a group of fixed-wing unmanned aerial vehicles. Unlike the existing works that only steer UAV swarm to achieve a fixed geometric pattern, our objective is to enable UAV swarm to maneuver as a group such that the centroid, scale and orientation of the formation can be continuously changed. The underlying graph of UAV swarm is assumed to satisfy a leader-first-follower structure, and the desired formation maneuvering parameters are only accessible to the leader. To address such issue, a cascaded control scheme is proposed. Firstly, we propose a distributed quaternion-based observer for each follower to estimate the desired orientation of the formation in finite time. Secondly, a bearing-based formation control law is developed to achieve the maneuvering formation, in which an adaptive-gain finite-time disturbance observer is synthesized to reject the deformations which vary the bearing constraints. It is demonstrated that the closed-loop formation tracking error converges to zero exponentially. Comparative simulations are preformed to demonstrate the effectiveness of the proposed method.

Large-scale single-crystal blue phase through holography lithography

The blue phase, which emerges between cholesteric and isotropic phases within a three-dimensional periodical superstructure, is of great significance in display and photonic applications. The crystalline orientation plays an important role in the macroscopic performance of the blue phase, where the single crystal shows higher uniformity over the polydomain and monodomain, resulting in higher Bragg reflection intensity, lower hysteresis, and lower driving voltage. However, currently reported methods of forming a single-crystal blue phase based on thermal controlling or e-beam lithography are quite time-consuming or expensive for large-scale fabrication, especially in the centimeter range, thus hindering the broad practical applications of single-crystal blue-phase-based photonic devices. Herein, a strategy to fabricate a large scale single crystalline blue-phase domain using holography lithography is proposed. Defect-free single-crystal domains both in blue phase I and blue phase II with a desired orientation of over 1 cm2 are fabricated based on a nanopatterned grating with periodic homeotropic and degenerate parallel anchoring, with colors from red and green to blue. This holography lithography-assisted strategy for fabrication of a large-scale single-crystal blue phase provides a time-saving and low-cost method for a defect-free single crystalline structure, leading to broad applications in liquid crystal displays, laser devices, adaptive optics elements, and electro-optical devices.

An empirical evaluation of enhanced teleportation for navigating large urban immersive virtual environments

Navigation is the most prevalent interaction in large urban virtual environments (VEs). Any Metaverse application that foresees navigating or exploring virtual cities requires an effective and efficient navigation technique. These environments, however, have distinct characteristics that make the navigation more challenging and the design of the interactions more critical. We have conducted an empirical study to assess how enhancing the teleportation technique with additional capabilities affects the performance of navigating large urban VEs. For this purpose, three interactions have been developed that extend the conventional point-and-click teleportation. The first one is named Mini-Map and provides a top-down view of the user’s surroundings. Portal Preview provides a preview of the selected target location and allows users to choose their desired orientation at that location. The last technique, called X-Ray Vision, makes the buildings around the user translucent and allows teleporting to locations that would otherwise be obscured. A within-subject controlled lab study with twenty five participants has been conducted, where each extension is evaluated individually as well as in combination with others. Our results show that extending the teleportation can significantly improve its performance when navigating large urban VEs. Overall, the X-Ray Vision was the most successful extension with respect to both task metrics and usability measures. Mini-Map was able to improve some of the task metrics, but did not have a significant effect on most self-reported measures. Portal Preview was the least effective extension, however, multiple participants liked the fact that they could define their desired orientation with the controller. Combining all interactions together performed well with respect to the task metrics, but this option was not favored by the participants. Extending the teleportation with X-Ray Vision and Mini-Map was by far the most favored option.

Static Stability and Swim Bladder Volume in the Bluegill Sunfish (Lepomis macrochirus).

Static stability is a property inherent to every organism. More stable bodies benefit from a lower energy cost associated with maintaining a desired orientation, while less stable bodies can be more maneuverable. The static stability of a fish is determined by the relative locations of its center of mass (COM) and center of buoyancy (COB), which may change with changes in swim bladder volume. We hypothesized, however, that fish would benefit from consistent static stability, and predicted that changes in swim bladder volume would not alter the overall pattern of COM and COB locations. We used micro-computed tomography to estimate the locations of the COM and COB in bluegill sunfish (Lepomis macrochirus). Using this technique, we were able to find a small but significant difference between the location of the COM and COB for a given orientation. We found that the swim bladder can change shape within the body cavity, changing relative locations of the COM and COB. At one extreme, the COB is located 0.441±0.007 BL from the snout and 0.190±0.010 BL from the ventral surface of the pelvic girdle, and that the COM is 0.0030±0.0020 BL posterior and 0.0006±0.0005 BL ventral to the COB, a pattern that causes a nose-up pitching torque. At the other extreme, the COM is anterior and dorsal to the COB, a pattern that causes the opposite torque. These changes in location seems to be caused by changes in the shape and centroid location of the swim bladder within the body: The centroid of the swim bladder is located significantly more posteriorly in fish oriented head-down. The air in the bladder "rises" while heavier tissues "sink," driving a change in tissue distribution and changing the location of the COM relative to the COB. Supporting our hypothesis, we found no correlation between swim bladder volume and the distance between the COM and COB. We conclude that bluegill are statically unstable, requiring them to expend energy constantly to maintain their normal orientation, but that the pitch angle of the body could alter the relative locations of COM and COB, changing their static stability.

Constructing a pyrene-based dimer in a crystal by adjusting the steric hindrance over the pyrene plane

The presence of an ortho-linked substituent in pyrene can lead to steric hindrance on one side of the pyrene plane, which prevents the formation of undesired interactions and promotes the selective formation of dimers in a desired orientation.