bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solving the Input/Output Problem for Planar Mechanisms
Authors: Nielsen James , Roth Bernard 
Published: February 2021

Abstract
This paper presents a method for solving the input/output problem for all planar mechanisms composed of revolute joints. The solution procedure is a modification of the Dixon resultant method, which was developed to solve sets of polynomial equations; in this paper the method is applied to sets of equations which are linear in the sines and cosines of unknown angles. A particular planar multi-circuit mechanism is analyzed to illustrate the solution procedure, and implementation details are discussed.
An Optimality Criteria Approach for the Topology Synthesis of Compliant Mechanisms
Authors: Saxena A. , Ananthasuresh G. K. 
Published: February 2021

Abstract
The physical insight used in formulating a multi-criteria optimization problem for the synthesis of compliant mechanisms, is quickly lost if mathematical programming techniques (SLP, SQP etc.) are used to determine the optimal solution. As opposed to the previous works that relied upon mathematical programming search techniques to find the optimum solution, in this paper we present an alternative method of solution called the optimality criteria method. Optimality criteria methods have proven to be effective in structural optimization problems with a large number of variables, and very few constraints as is the case in the topology synthesis of compliant mechanisms. The important new results of this paper include: (i) the derivation of a physically insightful optimal property of compliant mechanisms which states that the ratio of the mutual potential energy density and the strain energy density is uniform throughout the continuum (ii) the development of the optimality criteria method of solution in the form of a simple update formula for the design variables by using the above property (iii) design parameterization using the frame finite-element based ground-structure that appropriately accounts for the requisite bending behavior in the continuum, and (iv) numerical implementation of previously reported density based design parameterization using bilinear plane-stress elements. In addition, a new energy based multi-criteria objective function is presented to maximize the useful output energy (which is equivalent to maximizing the mechanical advantage) while meeting the kinematic requirements. Several examples are included to demonstrate the validity of the optimal property, the optimality-criteria method of solution, and the improvements made possible by the new energy based objective function.
Optimal Simultaneous Kinematic, Dynamic and Control Design of High Performance Manipulators Based on Trajectory Pattern Method
Authors: Rastegar J. , Liu L. , Mattice M. 
Published: February 2021

Abstract
An optimal simultaneous kinematic, dynamic and control design approach is proposed for high performance computer controlled machines such as robot manipulators. The approach is based on the Trajectory Pattern Method (TPM) and a fundamentally new design philosophy that such machines in general and ultra-high performance machines in particular must only be designed to perform a class or classes of motions effectively. In the proposed approach, given the structure of the manipulator, its kinematic, dynamic and control parameters are optimized simultaneously with the parameters that describe the selected trajectory pattern. In the example presented in this paper, a weighted sum of the norms of the higher harmonics appearing in the actuating torques and the integral of the position and velocity tracking errors are used to form the optimality criterion. The selected optimality criterion should yield a system that is optimally designed to accurately follow the specified trajectory at high speed. Other objective functions can be readily formulated to synthesize systems for optimal performance. The potentials of the developed method and its implementation for generally defined motion patterns are discussed.
A New Algorithm Based on Two Extra-Sensors for Real-Time Computation of the Actual Configuration of the Generalized Stewart-Gough Manipulator
Authors: Parenti-Castelli V. , Di Gregorio R. 
Published: February 2021

Abstract
It is well known that the direct position analysis of fully-parallel manipulators provides more than one solution, i.e., more than one configuration of the mechanism is possible for a given set of the actuated variables of motion. Extra information is, thus, necessary to find the actual configuration of the manipulator. This paper presents a new algorithm for the real-time computation of the actual configuration of the generalized Stewart-Gough manipulator, also known as 6-6 fully-parallel manipulator with general geometry. The proposed algorithm makes use of two extra rotary sensors in addition to the six normally implemented in the servosystems of the manipulator. A one-to-one correspondence between the sensor measurements and the manipulator configuration is provided. With respect to other algorithms recently presented in the literature, the proposed method greatly reduces the computational burden. Finally a case study shows the effectiveness of the proposed procedure.
A Gröbner-Sylvester Hybrid Method for Closed-Form Displacement Analysis of Mechanisms
Authors: Dhingra A. K. , Almadi A. N. , Kohli D. 
Published: February 2021

Abstract
The displacement analysis problem for planar and spatial mechanisms can be written as a system of multivariate polynomial equations. Elimination theory based on resultants and polynomial continuation are some of the methods which have been used to solve this problem. This paper presents a new approach to displacement analysis using the reduced Gröbner basis form of a system of equations under degree lexicographic (dlex) term ordering of its monomials and Sylvester’s Dialytic elimination method. Using the Gröbner-Sylvester hybrid approach, a finitely solvable system of equations F is transformed into its reduced Gröbner basis G using dlex term ordering. Next, using the entire or a subset of the set of generators in G, the Sylvester’s matrix is assembled. The vanishing of the resultant, given as the determinant of Sylvester’s matrix, yields the necessary and sufficient condition for the polynomials in G (as well as F) to have a common factor. The proposed approach appears to provide a systematic and rational procedure to the problem discussed by Roth (1994) dealing with the generation of (additional) equations for constructing the Sylvester’s matrix. Three examples illustrating the applicability of the proposed approach to displacement analysis of planar and spatial mechanisms are presented. The first and second examples deal with forward displacement analysis of the general 6-6 Stewart mechanism and the 6-6 Stewart platform, whereas the third example deals with the determination of the input-output polynomial of a 8-link 1-DOF mechanism which does not contain any 4-link loops.
Learning Control of a High-Speed Cam Dynamic System in the Presence of Viscous Damping and Coulomb Friction Theory and Experiment
Authors: Chew Meng-Sang , Wongratanaphisan Theeraphong , Lu Yi-Chen 
Published: February 2021

Abstract
This paper introduces the application of learning control theory to the intelligent control of an electromechanical cam-follower system. Learning control has been shown to handle inverse kinematics and inverse dynamics problems very well. It is a technique that can be applied to systems that perform repetitive tasks in order to reduce the errors that occur between the actual output and the desired output. Here, learning control is applied to a dynamic system containing nonlinear kinematics elements such as a cam. The learning process is based on output errors alone. It does not require explicit knowledge of the physical system. The presence of viscous damping and Coulomb friction both simplifies and challenges the learning control technique in compensating for such highly nonlinear dissipative effects within the cam-follower system. Results are presented based on the simulations of the system as well as the experiment. This study shows that learning control is capable of compensating for nonlinear Coulomb friction, that frequency occurs in the joints of many real world mechanisms.
Efficient Solution of Stiff ODE by Implicit Collocation Method
Authors: Pasic Hajrudin 
Published: February 2021

Abstract
When s-stage fully implicit collocation method is used to solve n–dimensional system of implicit ordinary differential equations (ODE) f(x, y, y’) = 0 the resulting algebraic system has a dimension sn. Its solution by Gauss elimination is expensive and requires s3n3 / 3 operations. In this paper we present an efficient algorithm which uncouples the algebraic system into a block-diagonal matrix with sn-dimensional blocks that may be solved in parallel. It applies to both explicit and implicit ODEs. The algorithm is formally different from the implicit Runge-Kutta (RK) method in that the solution for y is assumed to have a form of an algebraic polynomial whose coefficients are found by enforcing y to satisfy the differential equation at the collocation points. Locations of the collocation points are found from the derived stability function such as to guarantee both good stability and precision properties. Such a procedure leads to an algebraic system which has a sparse block-form and which may be easily diagonalized, providing an efficient solution of the problem, which is about s2 times faster than the Gauss elimination applied to the original, nondiagonalized system. In addition, the block-diagonal form of the algebraic system allows parallel processing and further increase of efficiency.
Error Transfer of Planar Linkages With Pair Clearance: Part 2 — The Effect of Dimension Type to the Error Transfer Coefficient
Authors: Li Song , Xianmin Zhang , Jian Yang 
Published: February 2021

Abstract
In this paper, based upon the method of Part 1, by the Monte-Carlo simulative experiment and the method of multivariate linear regression, the general regression equation of the planar linkage’s error transfer coefficient (ETC) for pair clearance is presented. And the regression equation is developed to display the effect of the driver relative length to ETC while the pair fit is invariable. The studying result shows that the regression equation of the effect of the driver’s relative length to ETC has the same form while the dimension type is variable. And through the curves, the effect of the dimension type to ETC and the output motion standard deviation of the mechanism is shown.
Natural Frequency Spectra and Vibration Modes of Planetary Gears
Authors: Lin Jian , Parker Robert G. 
Published: February 2021

Abstract
This work develops an analytical model of planetary gears and uses it to investigate their natural frequencies and vibration modes. The model admits three planar degrees of freedom for each of the sun, ring, carrier and planets. It includes key factors affecting planetary gear vibration such as gyroscopic effects, time-varying stiffness, and static transmission error excitation. For the linear time-invariant case, examination of the associated eigenvalue problem reveals the well-defined structure of the vibration modes, where the special structure results from the cyclic symmetry of planetary gears. Vibration modes are classified into rotational, translational and planet modes. The unique characteristics of each type of mode are analytically investigated in detail. For each class of mode, reduced-order eigenvalue problems are derived. The modal strain energy distributions are also discussed.
A Simple Method for Gear Ratio and Torque Analysis of Planetary Train Systems
Authors: Zhang Yi , Wu Zhi 
Published: February 2021

Abstract
Planetary gear train systems are widely used in automotive transmissions due to their compactness, large reduction ratios and degrees of freedom available for the selection of gear ratios. The analysis of gear ratios and torque relations among the elements of a planetary train system is often difficult due to the complexity of the planetary train structure. This is especially the case for automotive transmissions using planetary train system where the members for input and output and the members that are fixed or interconnected must be changed in the clutch engagement schedule to obtain multiple transmission speeds. This paper proposes a systematic approach that simplifies the gear ratio and torque analysis based on the basic planetary train characteristics. The approach can be effectively used for the analysis of gear ratio and static torques for power transmissions consisting of parallel planetary trains. A case study of multi-speed automotive transmission based on the approach is included in the paper.
Detecting Gear Tooth Breakage Using Acoustic Emission: A Feasibility and Sensor Placement Study
Authors: Singh Avinashchandra , Houser Donald R. , Vijayakar Sandeep 
Published: February 2021

Abstract
Vibration and debris monitoring methods are being increasingly used to detect gear tooth breakage. In this paper an alternate method of detecting gear tooth cracking is investigated. It is based on the phenomenon of acoustic emission (AE). The detectability of growing cracks using AE is established. Before this method can be used to detect crack growth in real systems, the transmissibility of these waves has to be studied. These waves have to propagate across a number of mechanical interfaces as they travel from the source to the sensor. The loss in strength of these waves at various interfaces commonly encountered in mechanical systems is studied in this paper.
Exploring the operationalisation and implementation of outreach in community settings with hard-to-reach and hidden populations: protocol for a scoping review
Authors: Krabbe Janina , Jiao Sunny , Guta Adrian , Slemon Allie , Cameron Aman Ahluwalia , Bungay Vicky 
Published: February 2021

IntroductionOutreach is regularly identified as an effective strategy to engage underserved, hard-to-reach and hidden populations with essential life-sustaining health services. Despite the increasing expansion of outreach programmes, particularly in HIV prevention and health promotion with youth, sex workers, people living with mental health and substance use challenges, and those affected by homelessness, there has been limited synthesis of the evidence concerning the core components of outreach programming or indicators of its successful implementation. Without this understanding, current outreach programmes may be limited in achieving the desired aims. The aim of this scoping review is to explore how outreach has been operationalised and implemented in various community settings with people underserved in current healthcare contexts. Understanding the state of knowledge pertaining to outreach as programming and as practice involving the engagement of people considered hard-to-reach will enable the identification of promising trends and limitations in the field.Methods and analysisThis scoping review follows the Arksey and O’Malley’s framework. CINAHL, MEDLINE, PsycINFO and PubMed databases will be searched for peer-reviewed references focused on outreach with hard-to-reach and hidden groups from 1 January 2008 to 30 April 2020. Guided by explicit inclusion and exclusion criteria, three reviewers will independently assess references in two successive stages. Titles and abstracts will be reviewed followed by full-text assessment of papers meeting the review criteria. A descriptive overview, tabular and/or graphical summaries and a thematic analysis will be carried out on extracted data.Ethics and disseminationEthics approval was not required as the only data source was peer-reviewed documents. Outreach knowledge users who are members of the project team will participate in all aspects of study design, implementation and result dissemination strategies.
Evaluation of the efficacy and impact of a clinical prediction tool to identify maltreatment associated with children’s burns
Authors: Hollen Linda , Bennett Verity , Nuttall Dianne , Emond Alan M , Kemp Alison 
Published: February 2021

BackgroundAn estimated 10%–24% of children attending emergency departments with a burn are maltreated.ObjectiveTo test whether a clinical prediction tool (Burns Risk assessment for Neglect or abuse Tool; BuRN-Tool) improved the recognition of maltreatment and increased the referral of high-risk children to safeguarding services for assessment.MethodsA prospective study of children presenting with burns to four UK hospitals (2015–2018), each centre providing a minimum of 200 cases before and after the introduction of the BuRN-Tool. The proportions of children referred to safeguarding services were compared preintervention and postintervention, and the relationship between referral and the recommended cut-off for concern (BuRN-Tool score (BT-score) ≥3) was explored.ResultsThe sample was 2443 children (median age 2 years). Nurses and junior doctors mainly completed the BuRN-Tool, and a BT-score was available for 90.8% of cases. After intervention, 28.4% (334/1174) had a BT-score ≥3 and were nearly five times more likely to be discussed with a senior clinician than those with a BT-score <3 (65.3% vs 13.4%, p<0.001). There was no overall difference in the proportion of safeguarding referrals preintervention and postintervention. After intervention, the proportion of referrals for safeguarding concerns was greater when the BT-score was ≥3 (p=0.05) but not for scores <3 (p=0.60). A BT-score of 3 as a cut-off for referral had a sensitivity of 72.1, a specificity of 82.7 and a positive likelihood ratio of 4.2.ConclusionsA BT-score ≥3 encouraged discussion of cases of concern with senior colleagues and increased the referral of <5 year-olds with safeguarding concerns to children’s social care.
Physiotherapy in palliative medicine: patient and caregiver wellness
Authors: Bernabeu-Wittel Máximo , Moreno-Gaviño Lourdes , Nieto-Martín Dolores , Lanseros-Tenllado Julia , Sáenz-Santamaría Ana , Martínez-Pérez Olga , Aguilera-Gonzalez Carmen , Pereira-Domínguez Manuel , Ollero-Baturone Manuel 
Published: February 2021

ObjectivesDespite the demonstrated efficacy of physiotherapy in palliative care programmes, there are scarce data of its real-life impact on patients’ and caregivers’ wellness and stress. Our aim was to assess effectiveness of a 30-day physiotherapy programme in psychological wellness and health-related quality of life (HRQoL) of patients with advanced chronic diseases or cancer and in their caregivers’ stress.MethodsQuasiexperimental before–after study applying personalised kinesitherapy, exercise with curative effects, respiratory physiotherapy, therapeutic massages and ergotherapy. Psychological wellness, HRQoL and caregiver’s strain outcomes were measured.Results207 patients (60% men, with a mean age of 73.6±12 years) were included; 129 (62.3%) with advanced cancer, and the remaining 78 with advanced chronic diseases. Psychological wellness (Emotional Stress Detection Tool decreased from 12.4±3 to 11±3; p<0.0001), caregiver’s strain (Caregiver Strain Index decreased from 8.5±3.2 to 7.9±3.5; p<0.0001) and HRQoL (WHO-BREF physical health domain increased from 8.3±2.6 to 9.4±2.9; p<0.0001) showed a significant improvement after the physiotherapy programme. Global satisfaction with the physiotherapy intervention was also high (Client Satisfaction Questionnaire-8 of 28.3±3.3 points).ConclusionsA personalised physiotherapy programme incorporated to integral palliative care improved psychological wellness, HRQoL and caregivers’ strain of patients with advanced chronic diseases and cancer.
Contraceptive dynamics during COVID-19 in sub-Saharan Africa: longitudinal evidence from Burkina Faso and Kenya
Authors: Karp Celia , Wood Shannon N , Guiella Georges , Gichangi Peter , Bell Suzanne O , Anglewicz Philip , Larson Elizabeth , Zimmerman Linnea , Moreau Caroline 
Published: February 2021

IntroductionEvidence from health emergencies suggests COVID-19 will disrupt women’s sexual and reproductive health (SRH). In sub-Saharan Africa, which experiences the highest rates of unintended pregnancy and unsafe abortion globally, COVID-19 is projected to slow recent progress toward universal access to contraceptive services.MethodsWe used longitudinal data collected from women at risk of unintended pregnancy in Burkina Faso (n=1186) and Kenya (n=2784) before (November 2019–February 2020) and during (May–July 2020) COVID-19 to quantify contraceptive dynamics during COVID-19; examine sociodemographic factors and COVID-19 experiences related to contraceptive dynamics; and assess COVID-19-related reasons for contraceptive non-use. Bivariate and multivariate logistic regressions were used to examine correlates of contraceptive dynamics amid COVID-19.ResultsMost women did not change their contraceptive status during COVID-19 (68.6% in Burkina Faso and 81.6% in Kenya) and those who did were more likely to adopt a method (25.4% and 13.1%, respectively) than to discontinue (6.0% and 5.3%, respectively). Most women who switched contraceptives were using methods as or more effective than their pre-pandemic contraception. Economic instability related to COVID-19 was associated with increased contraceptive protection in Burkina Faso but not in Kenya. Altogether, 14.4% of non-contraceptive users in Kenya and 3.8% in Burkina Faso identified COVID-19-related reasons for non-use.ConclusionsThe vast majority of women at risk of unintended pregnancy did not change their contraceptive status during COVID-19, and more women adopted than discontinued methods. A minority of women reported COVID-19-related reasons for non-use, underscoring the importance of expanding safe modes of service delivery during health crises.
Seed treatment and N rate do not impact dry bean (Phaseolus vulgarisL.) plant growth or grain yield in Ontario
Authors: Boersma Stephen J. , Gillard Chris L. 
Published: February 2021

Application of nitrogen fertilizer and commercial seed treatments are two strategies dry bean growers in Ontario utilize to manage root rot and maximize yields. However, data solidifying these practices is absent or outdated. Experiments were conducted at the Huron Research Station, near Exeter, Ontario, from 2008 to 2010, to measure plant growth and yield responses for navy, kidney, and cranberry dry bean market classes (cv. T9905, Pink Panther, and Etna, respectively) to seed treatment (NST, no seed treatment; CMBD, Cruiser Maxx Bean + Dynasty) and N fertilizer rates of 0, 35, 70, 105, 140, and 175 kg N·ha−1. Plant measurements taken included plant emergence, vigour, height and maturity, plant and seed mass, and grain moisture and yield. Over three years, plant growth and yield responses to seed treatment and nitrogen fertilizer were very scarce. Plant emergence and vigour either improved or were not affected by seed treatment or N rate, while increasing N rates increased plant height of only Pink Panther in 2008. Plant mass was unaffected by either factor while seed treatment decreased days to maturity and grain moisture of T9905 in 2008. Nitrogen fertilizer improved the grain yield of Etna, with the highest yields occurring with 70 kg N·ha−1or more, while other cultivar site–years did not respond. Overall, these results demonstrate dry beans rarely respond to N fertilizer or seed treatment at the Huron Research Station. Additional testing over multiple years and locations would assist in predicting these responses.