Search Results (71)

Proponents of Sexual Script Theory posit that men and women differ in their sexual behaviors/motivations, often due to culturally ingrained expectations. When these expectations are violated, individuals may face stigma, particularly in nontraditional contexts like mixed-sex threesomes (MSTs). This study examined gender differences in heterosexual adults’ anticipated stigma and willingness to accept various sexual offers, including dyadic and MST offers involving same- and other-sex partners, through the lens of the backlash effect (i.e., the anticipation of stigma for participating in sexual behaviors that contradict societal expectations). A total of 540 heterosexual U.S. adults read vignettes depicting hypothetical sexual invitations and completed measures assessing anticipated stigma and willingness to engage. Results revealed that men anticipated less stigma and were more willing to accept sexual offers than women. Participants also anticipated less stigma and reported greater willingness to accept other-sex dyadic offers as compared to same-sex or MST offers. However, men reported the highest anticipated stigma and lowest willingness for same-sex dyadic offers, suggesting a novel backlash effect against men engaging in gender non-conforming behaviors. These findings offer support for the persistence of the sexual double standard and provide evidence for gendered backlash effects, including those impacting heterosexual men. Full article

In order to improve mathematical model accuracy of electromechanical actuator (EMA) and solve the problems of low-frequency response and large overshoot for nonlinear systems by using traditional proportional integral derivative (PID) algorithm, a fuzzy single neuron (FSN)-PID algorithm is proposed. Firstly, a complete multi-nonlinear dynamic model of EMA is constructed, which introduces internal friction and current limiter of brushless direct current motors (BLDCMs), dead zone backlash of gear trains, and LuGre friction between output shaft and fin. Secondly, a FSN-PID controller is introduced into the automatic position regulator (APR) of EMA control system, where the gain coefficient K of SN algorithm is adjusted by fuzzy control, and the stability of the controller is proved. In addition, simulations are conducted on the response effect of different fin positions under different algorithms for the analysis of the 6° fin position response; it can be concluded that the rise time with FSN-PID algorithm can be reduced by about 4.561% compared to PID, about 1.954% compared to fuzzy (F)-PID, about 0.875% compared to single neuron (SN)-PID, and about 0.380% compared to back propagation (BP)-PID. For the 4°-2 Hz sine position tracking analysis, it can be concluded that the minimum phase error of FSN-PID algorithm is about 0.4705 ms, which is about 74.44% smaller than PID, about 73.43% smaller than F-PID, about 17.24% smaller than SN-PID, and about 10.81% smaller than BP-PID. Finally, wind tunnel experiments investigate the actual high dynamic flight environment and verify the excellent position tracking ability of FSN-PID algorithm. Full article

To address the unclear coupling mechanism between thermal elastohydrodynamic lubrication (TEHL) and dynamic behaviors in planetary gear systems, a novel tribo-dynamic model for dual-star planetary gears considering TEHL effects is proposed. In this model, a TEHL surrogate model is first established to determine the oil film thickness and sliding friction force along the tooth meshing line. Subsequently, the dynamic model of the dual-star planetary gear transmission system is developed through coordinate transformations of the dual-star gear train. Finally, by integrating lubrication effects into both time-varying mesh stiffness and time-varying backlash, a tribo-dynamic model for the dual-star planetary gear transmission system is established. The study reveals that the lubricant film thickness is positively correlated with relative sliding velocity but negatively correlated with unit line load. Under high-speed conditions, a thickened oil film induces premature meshing contact, leading to meshing impacts. In contrast, under high-torque conditions, tooth deformation dominates meshing force fluctuations while lubrication influence diminishes. By establishing a test bench for the planetary gear transmission system, the obtained simulation conclusions are verified. This research provides theoretical and experimental support for the design of high-reliability planetary gear systems. Full article

This study addresses the challenge of accurately modeling the dynamic behavior of industrial robots for precision manufacturing applications. Using a comprehensive experimental approach with modal impulse hammer testing and triaxial acceleration measurements, 360 frequency response functions were recorded along orthogonal measurement paths for a KUKA KR10 robot. Two dynamic models with different parameter dimensions (12-parameter and 24-parameter) were developed in Matlab/Simscape, and their parameters were identified using genetic algorithm optimization. The KUKA KR10 features Harmonic Drives at each joint, whose high transmission ratio and zero backlash characteristics significantly influence rotational dynamics and allow for meaningful static structural measurements. Objective functions based on the Frequency Response Assurance Criterion (FRAC) and Root Mean Square Error (RMSE) metrics were employed, utilizing a frequency-dependent weighting function. The performance of the models was evaluated across different robot configurations and frequency ranges. The 24-parameter model demonstrated significantly superior performance, achieving 70% overall average Global FRAC in the limited frequency range (≤200 Hz) compared to 41% for the 12-parameter model when optimized using a representative subset of 9 measurement points. Both models showed substantially better performance in the limited frequency range than in the full spectrum. This research provides a validated methodology for dynamic characterization of industrial robots and demonstrates that higher-dimensional models, incorporating transverse joint compliance, can accurately represent robot dynamics up to approximately 200 Hz. Future work will investigate nonlinear effects such as torsional stiffness hysteresis, particularly relevant for Harmonic Drive systems. Full article

This paper presents a robust tracking control strategy for servo systems with unknown backlash, employing adaptive parameter identification to address performance degradation caused by backlash nonlinearities. In high-precision positioning and rapid-response applications, backlash significantly compromises system performance. To address this challenge, a servo system model incorporating backlash nonlinearities is developed, and a novel adaptive inverse function is introduced for backlash compensation. The estimation error of unidentified parameters is indirectly obtained through the design of a state observer. Minimizing the estimation error facilitates the accurate identification of model parameters, encompassing those associated with backlash. Additionally, an adaptive law is designed to estimate the unknown upper bounds of disturbance dynamics. Then, a robust tracking controller is proposed, which dynamically adjusts control inputs in real time based on identified backlash parameters to counteract backlash-induced adverse effects. Theoretical analysis and simulation results demonstrate that the proposed strategy significantly improves tracking performance in servo systems with unknown backlash. Full article

In the digital age, consumer complaints have become significant indicators of operational vulnerabilities, with social media amplifying their impact. Mishandling such complaints has the potential to escalate minor issues into full-scale organizational crises, damaging brand reputation and eroding consumer trust. This study employs a case study approach to examine the Patiswiss Chocolate crisis, where a single consumer complaint led to widespread backlash, executive resignation, and boycotts. The crisis is analyzed through three key frameworks of analysis: communication, marketing, and ethics, offering a comprehensive understanding of its evolution. The findings reveal that defensive or dismissive responses exacerbate reputational damage, triggering the Streisand effect, where attempts to suppress criticism amplify its spread. Ethical concerns, including misleading corporate claims and governance issues, intensified consumer backlash. From a marketing perspective, brand trust declined as consumer activism influenced purchasing behavior and retailer decisions. This study emphasizes that organizations must adopt strategic, ethical, and consumer-centric approaches to crisis management to maintain long-term brand resilience. Full article

A high-gear-ratio anti-backlash 3K planetary gearbox with a preloaded flexure-based carrier is a suitable reducer for robot joints owning to its compact design and high transmission accuracy. However, to design such a 3K planetary gearbox with high bidirectional efficiencies for backdrivable robot joints, it is critical to develop an accurate transmission efficiency model to predict the effects of the preloaded flexure-based carrier on the efficiency of the 3K planetary gearbox. To determine the meshing forces of gear pairs in the 3K planetary gearbox, a quasi-static model is formulated according to tangential displacements of planet gears resulting from the preloaded flexure-based carrier. Considering the reverse meshing forces in the anti-backlash 3K planetary gearbox, a modified efficiency model is developed and the bidirectional transmission efficiencies are analyzed. Simulation results show that both forward and backward transmission efficiencies of the anti-backlash 3K planetary gearbox decrease as the preload increases, while they all increase with the increasing load torque. It is also revealed that the preload primarily affects the meshing efficiency of the sun–planet gear pair. Four different carrier prototypes are fabricated for experiments. The average errors between the predicted and measured results for forward and backward transmission efficiencies are 2.30% and 4.01%, respectively. Full article

Surface roughness and sliding friction are pivotal in determining the dynamic meshing performance of helical gears, especially under conditions of flexible support. In addition, the meshing parameters influenced by gear vibrations exhibit time-varying characteristics under flexible support stiffness, which is disregarded by many scholars. Based on this, a nonlinear dynamic model of a helical cylindrical gear system under flexible support conditions is developed, considering the coupling effects of dynamic friction and backlash influenced by fractal surface roughness. The motion differential equations of the system are derived using the Lagrange method, and numerical solutions are obtained through the Runge–Kutta method. The effect of several control parameters (driving speed, surface roughness and fractal dimension) on the dynamic response of gear system is studied, and the proposed dynamic model is compared with the traditional model under different support stiffness to demonstrate its adaptability to highly flexible support scenarios. The results indicate that the proposed dynamic model is better suited for flexible support structures. Moreover, the coupling effects of sliding friction and fractal backlash amplify the dynamic response of the gear system and introduce complex spectrum characteristics. This study provides theoretical guidance for the optimization of vibration and noise reduction designs in helical gear systems. Full article

Just and fair transitions to low-carbon and nature-positive ways of living need to occur fast enough to limit and reverse the climate and nature crises, but not so fast that the public is left behind. We propose the concept of “Regenerative Good Growth” (RGG) to replace the language and practice of extractive, bad GDP growth. RGG centres on the services provided by five renewable capitals: natural, social, human, cultural, and sustainable physical. The term “growth” tends to divide rather than unite, and so here we seek language and storylines that appeal to a newly emergent climate-concerned majority. Creative forms of public engagement that lead to response diversity will be essential to fostering action: when people feel coerced into adopting single options at pace, there is a danger of backlash or climate authoritarianism. Policy centred around storytelling can help create diverse public responses and institutional frameworks. The practises underpinning RGG have already created business opportunities, while delivering sharp falls in unit costs. Fast transitions and social tipping points are emerging in the agricultural, energy, and city sectors. Though further risks will emerge related to rebound effects and lack of decoupling of material consumption from GDP, RGG will help cut the externalities of economies. Full article

With advancements in small-scale research fields, precision manipulation has become crucial for interacting with small objects. As research progresses, the demand for higher precision in manipulation has led to the emergence of ultrahigh-precision engineering (UHPE), which exhibits significant potential for various applications. Traditional rigid-body manipulators suffer from issues like backlash and friction, limiting their effectiveness at smaller-scale applications. Smart materials, particularly piezoelectric materials, offer promising solutions with their rapid response and high resolution, making them ideal for creating efficient piezoelectric transducers. Meanwhile, compliant mechanisms, which use elastic deformation to transmit force and motion, eliminate inaccuracies induced by rigid-body mechanisms. Integrating piezoelectric transducers and compliant mechanisms into piezoelectric compliant devices enhances UHPE system performance. This paper reviews the recent advances in piezoelectric compliant devices. By focusing on the utilization of piezoelectric transducers and compliant mechanisms, their applications in perception, energy harvesting, and actuation have been surveyed, and future research suggestions are discussed. Full article

This paper designs a spatial photoelectric scanning mechanism that utilizes the large transmission ratio and reverses the self-locking performance of worm gears and gears. The institution uses a stepper motor to drive the worm gear component, thereby driving the worm gear to drive the alarm camera for spatial alarm imaging work. The stepper motor provides the driving force for motion, and, simultaneously, the alarm camera image can be compared with the star map to achieve position feedback. Therefore, this mechanism can achieve closed-loop control without angle measuring devices, achieving the lightweight design of the photoelectric scanning mechanism. Although this driving mechanism has many advantages, due to the micro-vibration formed by the gear backlash between teeth during the operation of the worm gear and worm, micro-vibrations are generated in the system, which can interfere with satellites with high precision requirements and affect their normal operation. This paper analyzes and experimentally verifies the principle of micro-vibrations in the worm gear and worm movement mechanism, and takes a certain photoelectric scanning turntable as an example to suppress micro-vibrations. The micro-vibration momentum level has been reduced from 7 N (at its peak) to 3.5 N (at its peak), with the number of targets increased by 50%, resulting in an effective suppression effect. Full article

In electromechanical systems, backlash in gear trains can lead to a degradation in control performance. We propose a drive–anti-drive mechanism to address this issue. It consists of two DC motors that operate in opposite directions. One motor acts as the drive, while the other serves as the anti-drive to compensate for the backlash. This work focuses on switching between the drive and anti-drive motors, controlled by a switched-mode PID controller. Simulation results on an inverted pendulum demonstrate that the proposed scheme effectively compensates for backlash, improving position accuracy and control. This switched controller approach enhances the performance of electromechanical systems, particularly where gear backlash poses challenges to closed-loop performance. Full article

Common rail systems are a key component of modern diesel engines and highly increase their performance. During their working lifetime, there could be critical damages or failures related to aging, like backlash or friction, or out-of-spec operating conditions, like low-quality fuel with, e.g., the presence of water or particles or a high percentage of biodiesel. In this work, suitable data-driven methods are adopted to develop an automatic procedure to monitor, diagnose, and estimate some types of faults in common rail systems. In particular, the pressure control loop operating within the engine control unit is investigated; the system is described using a Hammerstein model composed of a nonlinear model for the control valve behavior and an extended linear model for the process dynamics, which also accounts for the presence of external disturbances. Three different sources of oscillations can be successfully detected and quantified: valve stiction, aggressive controller tuning, and external disturbance. Selected case studies are used to demonstrate the effectiveness of the developed methodology. Full article

Nonlinear disturbances, such as friction, backlash, and base vibration, are the main factors restricting the further improvement of the dynamic performance of the Acquisition, Tracking and Pointing (ATP) system. However, the modeling and compensation of the time-varying nonlinearities are still challenging. In this paper, a compound control algorithm based on model predictive control (MPC) and a Proportional Multiple-Integral State-Augmented Kalman Filter (PMISAKF) disturbance observer is proposed to improve the disturbance rejection performance. Specifically, a PMISAKF is used to estimate the system’s state and external disturbances in real-time. These observed disturbances are then treated as known external inputs at the current or future time points and incorporated into the predictive model of MPC. This allows the optimization process to take these external factors into consideration, enabling the calculation of an optimal control strategy and achieving high pointing and tracking accuracy for nonlinear time-varying disturbances. Experimental results show that the proposed method can effectively improve the system’s anti-interference ability and tracking accuracy. Full article

To address the issues of low positional accuracy and significant torque pulsation caused by gear backlash and nonlinear friction in the mechanical transmission mechanism of aeronautical flap electromechanical actuators, we propose a model predictive control method for flap electromechanical actuator considering gear backlash and friction compensation. Firstly, we model the gear backlash in the electromechanical actuator’s mechanical transmission mechanism and design a corresponding torque current compensation method using a simplified dead zone model. Secondly, the LuGre compensation friction model is introduced, and a friction torque current compensation method is developed to address the nonlinear friction torque generated during system operation. Finally, the proposed current compensation strategies are employed to mitigate the adverse effects of gear backlash and nonlinear friction on system control performance. The simulation results demonstrate that the proposed method enhances position tracking accuracy, reduces torque pulsation, and significantly improves the overall control performance of the system. Full article