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The belt-drive control enables the mechanical system to gain the advantages of lightweight, vibration absorption and high torque, while it brings strong nonlinear disturbances due to friction, backlash and flexibility. Therefore an improved disturbance observer control method based on the dual-rate loop structure is proposed in this paper to suppress these disturbances. Only a linear low-frequency device model is required which indicates this method avoids the dependence on accurate identification of the nonlinear uncertain systems. The rate information on motor-side is replaced with the input signal of inner loop due to the high bandwidth of inner motor loop, which greatly simplifies the design of control system. In case of insufficient system bandwidth, the proposed method integrates the favorable information of the load-side and the motor-side under the DOB framework. And the speed-commutation spikes and chatters resulting from disturbances on the flexible transmission chain can be more effectively suppressed by the proposed control structure compared with the conventional methods.

Reduction gears are used in the joints of the robots. While precision and efficiency are required for industrial robot gearboxes, humanoid robots are expected to become more popular in the future. Flexibility must be considered in humanoid robots, and high back drivability shall be required. In this study, we aimed at realizing high efficiency, and high-precision reduction gears with high reduction ratios by maximizing the efficiency equation, hybridizing a 3K compound planetary reduction gearbox and traction drive, experimentally determining the efficiency, backlash, and angular velocity variation, and demonstrating the effectiveness of the proposed mechanism from a control perspective. In the experiments, we achieved a maximum forward driving efficiency of 90.90%, backward driving efficiency of 90.58%, and a minimum backlash of 1.18 arcmin.

A long-standing debate amongst international relations scholars has surrounded the question of whether international institutions with judicial authority enjoy more autonomy and discretion than other global institutions. This is mainly because international courts are established as impartial third-party actors tasked with performing adjudicative functions for conflicting parties. As such, the delegation contracts of international institutions with judicial authority are expected to minimize control by states, even in cases where the members of a court engage in judicial overreach. This article contributes to that debate by examining the case of the crisis of the WTO Appellate Body. The article analyzes the Trump administration's successful efforts at rendering dysfunctional one of the most powerful courts in the international system. The findings showcase how powerful states are capable and willing to take advantage of the available control mechanisms and the institutional opportunity structures inherent in the design of international courts. The article speaks to the scholarship on the contestation of international institutions. The analysis relies on original data obtained through 22 interviews with WTO officials, state representatives, and experts.

Conservative religious, activist and political groups fuel gender backlash in many spaces. This paper explores this phenomenon and its effects on educational programs designed to prevent gender-based violence in Brasilian schools. It argues that this gender backlash in educative spaces violates fundamental rights, like the right to equality and protection against discrimination and violence, and ultimately contributes to the continuity and escalation of gender-based violence in Brasil. This context shapes advocacy work and the facilitators and participants of its programs. Primary prevention research is mainly conducted in the Global North. This article, guided by a southern feminist framework and informed by 14 interviews with Brasilian advocates engaged in youth gender-based violence prevention programs, addresses a significant knowledge deficit and offers new insights in working in challenging contexts. It suggests that the backlash is mostly directed at LGBTIQA+ cohorts due to the ongoing political attacks on these groups, but it has also undermined the capacity of educational prevention strategies for gender-based violence more widely.

A gear is used not only for power transmission but also in precision positioning. A conventional and general gear has only one degree of freedom motion. Therefore, the case of its use is limited. In this paper, we propose and manufacture an innovative spherical gear. The proposed spherical gear has a multiple degrees of freedom motion. Compared with other spherical gear, the proposed spherical gear does not have complex shape. Moreover, the handle of the proposed spherical gear is similar to that of a spur gear. The experimental apparatus using the spherical gear pair measures a transmission efficiency and an angular backlash between the gears. According to experimental results, the spherical gear teeth could mesh firmly and transmit power at any shaft angle. In addition, the maximum transmission efficiency and the angular backlash become about 87.1% and 16.9 mrad when the shaft angle is 0°, respectively.

Muitas vezes o Poder Judiciário é provocado a se manifestar sobre questões extremamente controversas, que dividem tanto a opinião pública quanto a dos governantes e parlamentares. As decisões proferidas em tais casos podem gerar reações de descontentamento por parte da sociedade, do Poder Legislativo e do Executivo, que se utilizam de diversos meios para demonstrar sua insurgência contra o resultado apresentado pelo órgão julgador. Essas reações adversas são denominadas de backlash, expressão atribuída ao fenômeno supracitado pelo direito norte-americano. No presente artigo, será realizada uma análise do que é o backlash, bem como quais foram as principais reações legislativas verificadas no direito brasileiro até hoje. A pesquisa utilizou o método hipotético-dedutivo, partindo da teoria constitucional sobre influência de fatores externos nas decisões judiciais, para, em seguida, analisar o caso específico da ocorrência de reações legislativas a duas decisões proferidas pelo Supremo Tribunal Federal. As técnicas de pesquisa utilizadas consistem em pesquisa bibliográfica e jurisprudencial. Por fim, conclui-se que que o fenômeno do backlash é de suma importância em uma Estado Democrático, desde que haja uma corte constitucional atuante exercendo o papel contramajoritário.

In gear transmission servo systems, backlash effect and inertia variation often generate low precision, oscillations or even affect the stability. Focusing on this issue, an adaptive terminal integral sliding mode control (ATISMC) strategy and a discrete linear extended state observer (DLESO) are proposed in this article. First, different from using traditional dynamic model, a characteristic model is established with online parameter identification to describe inertia variation. Then, a DLESO is proposed to observe and compensate the modeling error caused by parameter identification and backlash effect. An ATISMC is newly designed based on the characteristic model to suppress the uncertainties and stabilize the whole closed-loop system. Both the uniform ultimate boundedness of observation error and the practical finite-time stability of the system is proved. Finally, simulation and experimental results demonstrate that the proposed strategy can adapt to large-range inertia variation and suppress the backlash effect.

This paper proposes a novel variable gain switching exact differential observer (SEDO) to deal with the state estimation of mechanical servo system with unknown backlash. In order to compensate unknown non‐linear backlash accurately, a switching backlash torque mathematic model is constructed to describe the input–output relationships of backlash. Then, based on the switching backlash torque mathematic model, a novel SEDO with variable gain strategy is implemented to compensate the influence of backlash and estimate system states accurately in terms of the change of real operation conditions. Moreover, the designed controller further alleviates the computational burden by conducting a feedforward compensation strategy, part of which is shared by the observer. It is proven that all the signals in the closed‐loop system are bounded, observation error and tracking error are convergent to a small compact set of the origin. Two simulations and two different motor servo test rigs are established to further illustrate the effectiveness of the proposed approach.

The tooth surface friction effects and the resulting tooth surface contact temperature are important factors for the dynamic characteristics of a gear-rotor system in compressed air energy storage (CAES). Therefore, a 3∘ of freedom finite-element model of the system is set up in which the lubrication state of the gear pair, tooth surface friction, contact temperature of the tooth surface, backlash and unbalanced excitation are considered. The friction coefficient is calculated according to the variation of the lubrication state, and the tooth surface contact temperature is derived based on the friction coefficient. The tooth profile deformation caused by the change in the contact temperature is calculated, and the resulting effects on backlash and comprehensive meshing stiffness are considered. The influence of rotating speed, torque load and viscosity of lubricating oil on the system response is studied, and the variation of the friction coefficient, flash temperature of the tooth surface, pressure of the tooth surface and so on are discussed in detail. The results indicate that when the friction coefficient is derived according to the variation of the lubrication state, the variation of the contact temperature of the tooth surface with rotating speed is quite different from that calculated based on a friction coefficient which is set artificially. This leads to a new variation of the dynamic response of the gear-rotor system, and the method of stabilizing the operation of the system is put forward based on the optimization curve for the operation of the system. The results obtained in this paper will provide a reference for the study and design of a gear-rotor system in CAES.

There are three main rolling nodes in the cycloidal gear reducer: the gear, output mechanism and central bearing. To transfer the drive from the active side to the output side of the gear, an output mechanism is used, which is formed by bushings mounted on pins located in the output shaft. During the operation of the reducer, the bushings roll around the wheel holes with a cycloidal contour. Using the structure and geometry of the output mechanism, an analysis of the backlash distribution in it was conducted, taking into account the machining deviations of the elements and surfaces forming this mechanism. Then, the distribution of forces and contact pressures were determined. The results of the analysis suggest that the backlash distribution, forces and contact pressures largely depend on the tolerance of the radius of the bushings’ arrangement and the holes in the planet wheel. The results obtained allow for the optimal selection of machining deviations in terms of received contact pressures.

In many mechatronic systems, gear transmission chains are often used to transmit motion and power between motors and loads, especially for light, small but large torque output systems. Gear transmission chains will inevitably bring backlash as well as elasticity of shafts and meshing teeth. All of these nonlinear factors will affect the performance of mechatronic systems. Anti-backlash gear systems can reduce the transmission error, but elasticity has to be considered too. The aim of this paper is to find the key parameters affecting the resonance and anti-resonance frequencies of anti-backlash gear systems and then to give the design optimization methods of improving performance, both from element parameters and mechanical designing. The anti-backlash geared servo system is modeled using a two-inertia approximate model; a method of computing the equivalent stiffness of anti-backlash gear train is proposed, which comprehensively considers the total backlash of transmission chain, gear mesh stiffness, gear shaft stiffness and torsional spring stiffness. With the s-domain block diagram model of the anti-backlash geared servo system, the influences of four main factors on the resonance and anti-resonance frequencies of system are analyzed by simulation according to the frequency response, and the simulation analysis results dependent on torsional spring stiffness of anti-backlash gear pair and load moment of inertia variation are verified by the experiment. The errors between simulation and experimental results are less than 10 Hz. With these simulation and experiment results, the design optimization methods of improving the resonance and anti-resonance frequencies such as designing the center distance adjusting mechanism to reduce the initial total backlash, increasing the stiffness of torsional spring and lightweight design of load are proposed in engineering applications.

The rapid pace of cannabis legalization in North America has provoked a backlash that is predictable and discouraging. The New Prohibitionists, distinct but related to their predecessors, the Old Prohibitionsists, have offered scholarship rife with conceptual errors, methodological flaws, and practical oversights. While their advice would likely hasten that which they seek to decrease, they overlook the costs of returning to practices associated with prohibition. To counter simplistic research interpretations and ill-considered policy, we present a critically informed research program on cannabis and crime based on previous scholarship. Our work is designed to apply replacement discourse and refocus research to withstand the tendency for justice systems to subvert, rather than embrace, reform. Cannabis legalization has been decades in the making and serious questions remain for proponents, opponents, and policymakers. Society, however, will be far worse off if the mistakes of reefer madness are repeated.

Purpose This paper aims to improve the meshing effect of the gear teeth. It is recommended to analyze the deformation difference between the inner and outer surfaces of the flexspline. The purpose of this paper is to modify the profile of the flexspline based on the deformation difference to improve the transmission accuracy and operating life of the harmonic drive. Design/methodology/approach In this paper, ring theory is used to calculate the deformation difference of the inner and outer surfaces of the flexspline, and the actual tooth profile of the flexspline is corrected based on the deformation difference. Then, the flexspline is divided into multiple sections along the axial direction, so that the three-dimensional tooth profile of the flexspline is modified to improve the gear tooth meshing effect. Findings This paper proves the effect of the deformation difference between the inner and outer surfaces of the flexspline on the tooth backlash, which affects the transmission accuracy and life of the harmonic drive. It is recommended to modify the tooth profile of the flexspline based on the deformation difference, so as to ensure the tooth meshing effect. Originality/value This paper provides a new way for the optimization of the three-dimensional tooth profile design of the harmonic drive.

The presence of backlash in servo system is always deteriorates the controller performance. It resulted in stability problem and poor steady state accuracy. The backlash is proportionate to the wear and tear caused by the friction during continuous movements of the transmission system in machine tool applications. Hence, there is a need to estimate the backlash on a continual basis and this information is fed back to the servo system in order to improve the controller performance. In general backlash error is occurred whenever there is a change in direction of the motor. In this work, the backlash is estimated by measuring backlash distance and this value is displayed in the user interface screen and that value can be added in software to compensate the backlash. The proposed methodology has an online estimation, which eliminates the necessity of physical sensors as compared to the earlier approaches.

President Franklin Delano Roosevelt shaped the role of the modern president in part with his relentless pursuit of grand policies and his ability to marshal historic legislation through Congress. In this article, I focus on one legislative tactic employed by FDR that has received little attention—the detailing of Executive Branch staff to select Senate committees. This tactic, effectively a blending of legislative powers, was used to implement FDR’s ambitious postwar domestic agenda as detailed in his Second Bill of Rights. I find that the tactic, used late in FDR’s presidency, was moderately effective, served as a substitute for the personal energy FDR applied to the presidency in his first term, and created a backlash that contributed to the adoption of the Legislative Reform Act of 1946. With these findings I conclude that FDR deserves credit as a transitionary figure for the modernity of Congress, as well as the presidency.

This paper focuses on the high performance pointing control of tank servo systems with parametric uncertainties and uncertain nonlinearities including nonlinear friction, backlash and structural flexibility. A comprehensive dynamic nonlinear mathematical model of the two-DOF tank servo system is established. Specifically, to accurately describe the nonlinear friction characteristics in actual systems, a continuous friction model is employed. Moreover, a hybrid nonlinear model combining structural flexibility and transmission backlash is constructed to characterize the nonlinear characteristics of the backlash and flexible coupling between the input and output shafts of the drive end for the tank servo system. By using the backstepping method, a nonlinear adaptive robust controller is presented. In the controller, the adaptive law is compounded to dispose of parametric uncertainties and a well-designed continuous nonlinear robust control law is developed for the purpose of coping with unmodeled disturbances. The closed-loop system stability analysis indicates that the presented controller achieves an asymptotic tracking performance with parametric uncertainties and ensures the robustness against unmodeled disturbances theoretically. The effectiveness of the proposed control strategy is verified by a large number of comparative simulation results.

This paper describes a surgical device that uses a compensation mechanism without motors and electronics to reduce the backlash in the end-effector. The device improves the precision and accuracy of surgical operations that involve unpredictable curved paths at a low cost. The device includes a flexible tube that moves along a curved path and a mechanism that compensates for the change in the length of the wire that actuates the end-effector as it follows an unpredictable path. The compensation mechanism minimizes the wire slack by utilizing a slider and spring mechanism that can maintain the pull wire length but can also move freely to extend the wire length as needed. We maximized the compensable wire length by optimizing the device driving parameters via simulation, verified the device performance experimentally, and built a fully operational prototype. The backlash of the device end-effector was reduced by approximately 38.3% compared to a device without compensation. Surgeons used the prototype with animal models in vivo and evaluated it as convenient and easy to manipulate. A hand-held non-robotic surgical device that compensates for wire length in unexpected curved paths to reduce end-effector backlash was demonstrated. The performance of the prototype was validated by driving, backlash, and hysteresis measurements, and in vivo animal experiments. This study is a significant step towards the development of a high-precision and low-cost surgical device for use in deep and narrow anatomies with unpredictable curved paths.

This article considers the recent ‘Backlash’ against global norms and institutions fuelled by various contemporary political developments within and between states. Understanding the shape, significance and drivers of this phenomenon better is a pre-requisite to developing and analysing possible responses by Australia and other states. The recent rise of populism and ‘illiberal democracy’ especially within major Western democracies has challenged the longstanding and widespread commitment of those states to the rules-based order. These phenomena have also eroded the traditional global leadership, in multilateral forums, of key powers including UN permanent members the United States and the United Kingdom. The populations of these and other states have responded to perceptions of economic and political disempowerment by pressuring political representatives to focus their energies domestically. In order both to appeal and respond to domestic political forces, leaders in these states have sought to target or sometimes scapegoat the international institutions that have hitherto been so useful to their foreign policy agenda. This article examines the consequences of understanding the current populist moment as part of a Backlash against global law and institutions and the ramifications of the Backlash frame for international peace and security. It also considers the implications of the Backlash frame for the international human rights system, the impact of the turn inward for global trade and finance and the Backlash against environmental norms.

A two-dimensional non-linear dynamics model of a gear with meshing beyond pitch point with six degrees has been established, considering time-varying meshing stiffness, time-varying bearing stiffness, time-varying friction, backlash and bearing clearance. Time-varying meshing stiffness is computed by using material mechanics method. The friction coefficient of Coulomb model and the friction coefficient of EHL theory are analyzed and compared in dynamic response. The global bifurcation characteristics caused by input speed, backlash, bearing clearance and damping are investigated. The maximum Lyapunov exponent which leads to chaos characters effect of changing parameters is analyzed. The verification experiment is carried out on the CL-100 test rig. Meshing frequency has main impact on vibration acceleration of ordinary spur gear and double meshing frequency has main impact on vibration acceleration of gear with meshing beyond pitch point. The results show that the gear with meshing beyond is better than ordinary spur gear whether in bifurcation characteristics or in vibration acceleration response.

In the U.S., and elsewhere, populism has been democracy’s way of shaking elites up. We can view populism in part as a revolt of the losers, or perceived losers, of globalization. Yet elites have often paid too little heed to the domestic distributive impact of high immigration and globalized trade. Immigration and globalization are also spurring forms of nativism and demagoguery that threaten both democratic deliberation and undermine progressive political coalitions. The challenge now is to find the most reasonable – or least unreasonable – responses to the new politics of resentment: ways that recognize that egalitarian liberalism and social democracy are national projects and preserve progressive political coalitions, while also acknowledging our interconnections, duties, and moral obligations to those beyond our borders.

In 2017, transgender woman Danica Roem stunned political observers in Virginia by unseating a long-time anti-LGBTQ legislator from a conservative district in the Virginia House of Delegates.1 She was the first openly transgender person elected and seated to a state legislature. Delegate Roem’s election was historic in LGBTQ political representation, but it also occurred in a period when backlash against the LGBTQ community seemed to be growing (Taylor, Lewis, and Haider-Markel 2018). These two threads led us to ask: How are LGBTQ candidates achieving historic successes even as forces seem mobilized against them?

In the aftermath of the far-right rally in Charlottesville that led to the murder of counter-protester Heather Heyer in August 2017, attention turned to the reaction by extremists on far-right webs...

Understanding the “backlash” it is facing is a necessary condition for a successful reform of international investment law and arbitration. The article develops a typology of backlash in international investment law and arbitration, identifying three main tensions in the field: contractualism vs. unilateralism; economic rationality vs. political rationality; flat world view vs. diverse world view. The article claims that the reform discussion, including at the UNCITRAL level, should be informed by this backlash typology. Two main lessons may be learned, one at the methodological level and one at the substantive level: first, the reform discussion needs to be informed by the study of systems of domestic investment law and policy; second, the reform discussion needs to move beyond its Investor-State Dispute Settlement (ISDS) confines and also include reform of the substantive law and administrative procedures of States and of international treaties.

Gear backlash is a nonlinear effect of the gear system. In a spur gear system with the backlash, the initial position of gears with the backlash affects the impact force. This work conducted a dynamic analysis of the spur gear system with time-varying mesh stiffness and bearing stiffness with a focus on the initial gear position within the backlash. For this purpose, the time-varying stiffness of the gears and rolling bearings were calculated. Mesh force with the time-varying stiffness and the gear backlash was applied to four DOF equations of motion. The equations of motion were solved using the Newmark beta method and Newton-Raphson method. The dynamic characteristics of the spur gear system by the initial position of gears within the backlash were investigated along with the magnitude of the backlash. The results showed that as the backlash increased, the mesh and bearing forces increased as well. The mesh and bearing forces were highly dependent on the initial gear position within the backlash. Significant initial mesh and bearing forces by the initial gear position within the backlash can lead to cumulative damages to the gear system.

This paper works on the oscillation of electrified powertrain system in an integrated manner where combined mechanical-electric-network effects are all taking into consideration, and a robust oscillation controller is proposed to suppress the effects-caused oscillation and to maintain the system stability. An integrated model is developed in which driving motor, drivetrain and communication network are all included. Thus, torque ripples in the driving motor, nonlinear gear backlash as well as driveshaft flexibility in the drivetrain and network-induced delays that may cause powertrain system oscillation can be all considered. In order to dealing with the coupling effects of network-induced delays and event-driven manner of the controller nodes, a delay-free discrete model is further built via polytopic inclusion approach and system augmentation technique. An energy-to-peak performance based robust controller is proposed to ensure the torsional oscillation damping as well as vehicle speed tracking performance. During backlash mode, as the driving motor and the load are decoupled, a sliding mode compensator is further adopted to restrain the torsional oscillation. The stability of electrified powertrain control system is ensured by using Lyapunov theory, and the controller gain is obtained by solving a set of linear matrix inequalities (LMIs). Comparative simulation tests are carried out by using Matlab/Simulink in which a delicate controller area network (CAN) model is developed via SimEvent. The combined mechanical-electric-networked effects on torsional oscillation are demonstrated during the simulation tests, while the performance of the proposed controller is well verified.

For the nonlinear vibration problem of spur gear transmission system caused by friction and gear backlash, the dynamic model of gearbox with 16-degree-of-freedom (16-DOF) considering time-varying meshing stiffness is established by Lagrange equation. The dynamic equations of the gear system are solved by the Newmark-β method. The effects of friction coefficient, error fluctuation and meshing stiffness on the vibration response are investigated. In order to verify the validity of the model, a spur gear transmission rotor test bench was built by simulating the actual working conditions. The root mean square (RMS) is used to verify the accuracy of the model at multiple speeds, and makes up for the shortcomings of many researches without experimental argumentation. The experimental research can provide a reference for the research of gear transmission system.

For high-precision control in a ball-screw driven servo system, the full-closed loop position control structure with position measurements from both the drive side and the load side are usually required. However, compared with semi-closed loop position control, if only the load side position feedback is being used, then the inherent elastic link is included in the position loop, and the mechanical vibration will be easily induced. For this situation, the stability of the servo system will be affected. Moreover, in the ball-screw driven servo system, the backlash and friction in the mechanical transmission chain will introduce a typical contour error–over-quadrant error, which cannot be eliminated by adopting full-closed loop control. In order to maintain stability and high precision positioning performance, both vibration suppression and over-quadrant error mitigation methods are proposed in this paper. First, the model of full-closed loop position control system is established, on this basis, the reasons that why the full-closed loop control is more easily to induce the position vibration than the semi-closed loop control is analyzed. Then, a dual-position feedback control method, by introducing the drive side position information with a filter to the position loop feedback channel, is proposed, which combines the advantages of semi-closed loop control and full-closed loop, and features high gain margin and high control precision. Furthermore, based on the analysis of the mechanism of over-quadrant error, an adaptive backlash error compensation method which can reduce the over-quadrant error is proposed. Finally, simulation and experimental results in both single axis and dual axis are provided to demonstrate the feasibility and effectiveness of the proposed methods.

States are investing heavily in artificial intelligence (AI) technology, and are actively incorporating AI tools across the full spectrum of their decision-making processes. However, AI tools are currently deployed without a full understanding of their impact on individuals or society, and in the absence of effective domestic or international regulatory frameworks. Although this haste to deploy is understandable given AI's significant potential, it is unsatisfactory. The inappropriate deployment of AI technologies risks litigation, public backlash, and harm to human rights. In turn, this is likely to delay or frustrate beneficial AI deployments. This essay suggests that human rights law offers a solution. It provides an organizing framework that states should draw on to guide their decisions to deploy AI (or not), and can facilitate the clear and transparent justification of those decisions.

A theoretical model of the operation of the electromechanical mechanism for clamping cylindrical workpieces and tools on the spindle of metalworking machines during backlash elimination is considered. The considered design of the clamping mechanism is driven by an electric motor and has many advantages. Based on the model, analytical dependencies are proposed that describe the relationship between the movements of the elements of the mechanism during the first stage of the clamping process. The proposed analytical dependencies allow taking into account stages of the mechanism's functioning when the forces of dissipative characters prevail in its work. The presented dependencies describe the position of the elements of the machine depending on the generalized coordinate, which is the angle of rotation of the electric motor rotor. It allows determining the position of the elements of the mechanism depending on time. The obtained dependencies are a precondition for developing methods for optimizing the design of mechanisms of this type.

The aim of this paper is to establish a typical gear coupled rotor system model and give an analysis of the early wear of the tooth surface. The tooth surface wear will cause the change of the backlash. Different from previous studies on the backlash, the backlash in this paper is a dynamic fractal backlash, which is obtained based on the fractal wear model of tooth surfaces. Firstly, based on the FA (Flodin and Andersson) model and our previous studies on the contact analysis of rough surfaces, a fractal wear model of tooth surfaces is established. Then, the system vibration response of embedded dynamic fractal backlash is compared with that of embedded fixed backlash. The results show that the traditional fixed backlash cannot reflect the small changes of the system response, while the dynamic fractal backlash can sensitively reflect changes of dynamic characteristics of the system, so this kind of mathematical model considering dynamic fractal wear will be more conducive to the analysis and prediction of gear wear faults in engineering.

A differential mechanism is a cardinal component in most automobile applications. A systematic understanding of vibration properties of the differential mechanism is meager due to the fact that the arrangement of the bevel gear making up the mechanism is unique and poses difficulties for conducting dynamic analysis. As a result, a theoretical formulation of the system is highly required to pave the way for design improvement and further research. To fill this knowledge gap, this study aims to scrutinize the vibration properties of the automotive differential by taking into account the flexibility of the bearing, time-varying feature of mesh stiffnesses, and backlashes between gear meshes. To do so, the Euler-Lagrange formulation has been used to derive the dynamic equations governing the motion of the differential. The analytical expressions of the mesh phasing relations among gear meshes in the system have been determined. The positions of the bearings and their stiffness values have been optimized by means of particle swarm optimization in order to mitigate the vibration. Also, the effects of mass imbalance on the dynamic performance of the system have been revealed. The impact of the presence of eccentricity in the gear (12) has been pinpointed. Besides, the influence of the backlash in the first gear mesh has been detected. This study may provide an important opportunity to advance the understanding of the dynamic features of the differential system with and without various types of defects.

Full closed loop servo drive system is widely used in industry and medical field, and it is an ideal control scheme to achieve high precision position control. In this paper, by analyzing the dead-zone model of backlash and LuGre friction model, a compound two-mass full-closed-loop system with backlash and friction is established. The position response of the compound system is analyzed by description function method and simulation. Finally, it is concluded that friction can eliminate the characteristic of the limit cycle by the backlash, and the amplitude of the backlash will affect the duration of the flat at the crest.

Chapter 1 explores the tensions that arose in southern evangelicalism between local church congregations and state- and nation-level bodies in the wake of the 1954 Brown decision. Such tensions reveal how Southern Baptists and Methodists negotiated the heightened antagonism emerging between denominational leaders and the people in the pews over civil rights in the mid-1950s. The chapter opens with South Carolina Southern Baptist churches rejecting broader Southern Baptist Convention efforts to advocate for civil rights in religious language and concludes with lay South Carolina Methodists defending the White Citizens’ Councils against criticism from a small number of Methodist clergy. Both these studies reveal the effective authority of local congregations in directing southern white churches’ responses to matters of race in the civil rights years. This chapter highlights that the congregational-level perspective gives the best vantage point for understanding white evangelicalism’s response to the civil rights movement, regardless of church polity.

International audience; Industrial robotics and aerospace engineering widely use harmonic drive gearboxes for their reliability, high accuracy with zero backlash and high ratio torque transmission However, they present known problematic behaviors that affect their performance. The article deals with the first step towards the improvement of torque control of collaborative robots. We designed and developed two experimental setups to study three types of Harmonic Drive gearboxes. We identify the friction laws by using Force Transfer Diagrams. The results exhibit a new parabolic law of friction torque as a function of the transmitted torque.

As an important factor leading to the failure of gear system, the study of thermal effect is insufficiently deep. Based on the finite element nodal method, a more comprehensive dynamic model of gear-rotor-bearing system is established, which considers the thermal related material properties, time-varying meshing stiffness (TVMS), backlash and friction, gyroscopic effect. The constitutive relation of beam element considering steady-state temperature is reconstructed, and thermal node load is formulated. Considering the influence of temperature on the material properties of flexible shaft and gear, the thermal related TVMS and thermal backlash are obtained. The dynamic response of the system under different steady-state temperature fields is compared, and the influence of hot backlash is studied, then the thermal related vibration characteristics are obtained. Besides, the influence of bearing type on bearing force and axial trajectory is studied. The results show that the system motion changes from period to chaos with the temperature increase in part of the speed range. The appropriate backlash is helpful to restrain the chaotic motion caused by temperature rise. Moreover, the temperature can significantly increase the axial bearing force, and the appropriate bearing can reduce the axial displacement.

The overwhelming majority of unsuccessful petitions in the Organization of American States’ Inter-American human rights system are unsuccessful because they are dismissed at the pre-admissibility or admissibility phase rather than at the merits phase. Although this preliminary screening of applications constitutes the major obstacle to petitioners seeking justice, there has been relatively little scholarly analysis of the potential interplay of legal and attitudinal factors at this phase. That is, whether this phase may be where the biases that the system has been accused of (i.e., bias against leftist regimes and a “hierarchization” of negative rights and liberties over social justice) manifest themselves. This article fills this gap in the literature by undertaking a comprehensive quantitative analysis of Inter-American Commission on Human Rights admissibility decisions that measures the impact of a broad range of factors and compares the dynamics of admissibility decisions with those of merits decisions. In so doing, it places into context backlash against the system that has led to recent changes in the system’s procedures.

The author uses Critical Discourse Analysis to compare two legal documents of critical relevance for the rights of children in conflict with the law in Argentina: the current law no. 22,278, called Régimen Penal de la Minoridad, and the project named Sistema de Responsabilidad Penal Juvenil which was under consideration by the National Congress during 2019. This project was proposed by the government so as to stablish a new juvenile justice system in Argentina, following a widely spread tendency in the Latin American region. The purpose of the article is to show that, even though the language of human rights is used in official discourse and in the legal text submitted to Parliament, many of its features represent a clear backlash to a more conservative regime.

The United States initiated sweeping counterterrorism efforts after the September 11, 2001 terrorist attacks. This study tests a backlash hypothesis as it relates to the nature of attacks against the US abroad. Relying on data from the Global Terrorism Database, this study uses a quasi-experimental design to investigate whether attacks against the US abroad became more or less lethal after 9/11. There is a significant increase in the proportion of attacks with fatalities and a significant decrease in the proportions of non-lethal attacks against US targets and interests overseas after 9/11. The results suggest a redistribution in the lethality of attacks against the US abroad. This study finds evidence of a backlash of deadlier terrorism violence against the US abroad after September 11. Examining for unintended consequences is an important facet of terrorism prevention research and policy.

Trial advocacy education often stresses the importance of attorneys expressing arguments with emotion to signal conviction. Yet, female attorneys must approach this advice with caution given potential backlash for expressing emotions traditionally considered masculine, like anger. Two experiments (Study 1, N = 220; Study 2, N = 273) demonstrated that people most likely to endorse traditional gender roles exhibited bias against female attorneys expressing anger in court. Participants were recruited nationally and randomly assigned to view an attorney delivering a closing statement in court who either (1) was a man or a woman, and (2) used a neutral or angry tone. They reported how hirable and effective they perceived the attorneys to be and completed measures of several individual difference factors that are established predictors of endorsement of traditional gender roles: ambivalent sexism, political conservatism, and age. Participants who were more likely to hold traditional gender values (i.e., more benevolently sexist, more politically conservative, and older) were more likely to favor attorneys who conformed to gender norms (i.e., male attorneys who expressed anger relative to no anger) and less likely to favor attorneys who violated gender norms (i.e., female attorneys who expressed anger relative to no anger). Thus, female attorneys are faced with the challenge of walking the line between exhibiting traditionally masculine behaviors that are valued by the legal system—but not so much so that they suffer backlash for violating gender norms.

The commonly shared sentiment that human rights have reached a crisis in the form of a populist backlash has produced a vibrant discussion on the causes of and solutions to the crisis. This article seeks to contribute to that discussion by engaging with Philip Alston's important and influential essay on the topic, and in particular with his project of tackling material inequality. While agreeing with Alston that a key reason for the populist backlash is material inequality, the article challenges his view that the solution to the problem is to double down on ‘familiar strategies’ by simply providing social and economic rights a more prominent position within the human rights project. By contrast, the article suggests that a radical renewal of the human rights movement is called for – one accompanied by a more elaborate diagnosis of how human rights have been linked to inequalities and how they can engage with the structures and actors producing those inequalities. Trying to understand why human rights have lost ground to nationalism, the article suggests that a first step towards such more radical and dynamic human rights might be to unearth the now largely forgotten concept of solidarity.

In the previous nonlinear dynamic models of spur gear system, when considering bearing deformation, the pressure angle and gear backlash are usually considered as constants to facilitate the modelling. In fact, bearing deformation will cause the gear translation motion, and then lead to the changes of a series of gear mesh parameters. In view of this, this paper presents a new nonlinear dynamic model for a spur gear system considering the time-varying behaviors of pressure angle and gear backlash, together with the effects of gear gravity, unbalance mass, and internal/external excitations, etc. The equations of motion of the system are strictly derived using Lagrange method and solved by the numerical integral method. The time-varying mesh stiffness is calculated by the potential energy method based on an improved mesh stiffness model. Afterwards, the new model is compared with the previous model and some dynamic characteristic differences between the two models are demonstrated using the rotating speed and backlash as control parameters. This results shows that due to the effects of the time-varying pressure angle and backlash, the system may enter into chaotic motion in advance and the tooth impact state will also alter. This research can provide a useful source of reference for dynamic design of gear transmission system and the further study of spur gear system.