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Considering the response lag and viscous slip oscillation of the system caused by cylinder piston friction during automatic polishing of aero-engine blades by a robotic pneumatic end-effector, the purpose of this study is to propose a constant force control method with adaptive friction compensation.

First, the mathematical model of the pneumatic end-effector is established based on the continuous LuGre model, and the static parameters of the LuGre model are identified to verify the necessity of friction compensation. Second, aiming at the problems of difficult identification of dynamic parameters and unmeasurable internal states in the LuGre model, the parameter adaptive law and friction state observer are designed to estimate these parameters online. Finally, an adaptive friction compensation backstepping controller is designed to improve the response speed and polishing force control accuracy of the system.

Simulation and experimental results show that, compared with proportion integration differentiation, extended state observer-based active disturbance rejection controller and integral sliding mode controller, the proposed method can quickly and effectively suppress the polishing force fluctuation caused by nonlinear friction and significantly improve the blade quality.

The pneumatic force control method combining backstepping control with the friction adaptive compensation based on LuGre friction model is studied, which effectively suppresses the fluctuation of normal polishing force.

This paper aims to present a control method to realize the constant force grinding of automobile wheel hub.

A constant force control strategy combined by extended state observer (ESO) and backstepping control is proposed. ESO is used to estimate the total disturbance to improve the anti-interference and stability of the system and Backstepping control is used to improve the response speed of the system.

The simulation and grinding experimental results show that, compared with the proportional integral differential control and active disturbance rejection control, the designed controller can improve the dynamic response performance and anti-interference ability of the system and can quickly track the expected force and improve the grinding quality of the hub surface.

The main contribution of this paper lies in the proposed of a new constant force control strategy, which significantly improved the stability and precision of grinding force.

Considering the influence of environmental noise and modeling error during the process of the robotic automatic grinding aero-engine blade, this study aims to propose a method based on the extended state observer (ESO) to reduce the fluctuation of normal grinding force.

First, the measurement range of the six-dimensional force sensor is calibrated according to the maximum acceleration of end-effector and grinding force. Second, the gravity and zero drift compensation model is built to compensate for measurement error. Finally, the switching function is designed based on the difference between the expected grinding force and the actual feedback value. When the value of function stays within the switching band, a nonlinear active disturbance rejection control (ADRC) loop is applied. When the function value reaches outside the switching band, an ESO-based sliding mode control (SMC) loop is applied.

The simulated and experimental results show that the proposed control method has higher robustness compared with proportion-integral-derivative (PID), Fuzzy PID and ADRC.

The processing parameters of this paper are obtained based on the single-factor experiment without considering the correlation between these variables. A new control strategy is proposed, which is not only used to control the grinding force of blades but also promotes the development of industrial control.

ESO is used to observe environmental interference and modeling errors of the system for real-time compensation. The segment control method consisting of ESO-based SMC and ESO-based ADRC is designed to improve the robustness. The common application of the two parts realizes suppression of fluctuation of grinding force.

This study aims to realize the constant force grinding of automobile wheel hub.

A force control strategy of backstepping + proportion integration differentiation (PID) is proposed. The grinding end effector is installed on the flange of the robot. The robot controls the position and posture of the grinding end actuator and the grinding end actuator controls the grinding force output. First, the modeling and analysis of the grinding end effector are carried out, and then the backstepping + PID method is adopted to control the grinding end effector to track the expected grinding force. Finally, the feasibility of the proposed method is verified by simulation and experiment.

The simulation and experimental results show that the backstepping + PID strategy can track the expected force quickly, and improve the dynamic response performance of the system and the quality of grinding and polishing of automobile wheel hub.

The mathematical model is based on the pneumatic system and ideal gas, and ignores the influence of friction in the working process of the cylinder, so the mathematical model proposed in this study has certain limitations. A new control strategy is proposed, which is not only used to control the grinding force of automobile wheels, but also promotes the development of industrial control.

The automatic constant force grinding of automobile wheel hub is realized, and the manpower is liberated.

First, the modeling and analysis of the grinding end effector are carried out, and then the backstepping + PID method is adopted to control the grinding end effector to track the expected grinding force. The nonlinear model of the system is controlled by backstepping method, and in the process, the linear system composed of errors is obtained, and then the linear system is controlled by PID to realize the combination of backstepping and PID control.

High residual stress caused by the high temperature gradient brings undesired effects such as shrinkage and cracking in selective laser melting (SLM). The purpose of this study is to predict the residual stress distribution and the effect of process parameters on the residual stress of selective laser melted (SLMed) Inconel 718 thin-walled part.

A three-dimensional (3D) indirect sequentially coupled thermal–mechanical finite element model was developed to predict the residual stress distribution of SLMed Inconel 718 thin-walled part. The material properties dependent on temperature were taken into account in both thermal and mechanical analyses, and the thermal elastic–plastic behavior of the material was also considered.

The residual stress changes from compressive stress to tensile stress along the deposition direction, and the residual stress increases with the deposition height. The maximum stress occurs at both ends of the interface between the part and substrate, while the second largest stress occurs near the top center of the part. The residual stress increases with the laser power, with the maximum equivalent stress increasing by 21.79 per cent as the laser power increases from 250 to 450 W. The residual stress decreases with an increase in scan speed with a reduction in the maximum equivalent stress of 13.67 per cent, as the scan speed increases from 500 to 1,000 mm/s. The residual stress decreases with an increase in layer thickness, and the maximum equivalent stress reduces by 33.12 per cent as the layer thickness increases from 20 to 60µm.

The residual stress distribution and effect of process parameters on the residual stress of SLMed Inconel 718 thin-walled part are investigated in detail. This study provides a better understanding of the residual stress in SLM and constructive guidance for process parameters optimization.

This chapter examines how the breakthrough of Zhang Ziyi's depiction of a female kung fu master in The Grandmaster (2013) transforms the figure of the heroine in Chinese action films. Zhang is well known for her acting in action films conducted by renowned directors, such as Ang Lee, Zhang Yimou and Wong Kar-wai. After winning 12 different Best Actress awards for her portrayal of Gong Ruomei in The Grandmaster, Zhang announced that she would no longer perform in any action films to show her highest respect for the superlative character Gong. Tracing Zhang's transformational portrait of a heroine in The Grandmaster alongside her other action roles, this analysis demonstrates how her performance projects the directors' distinctive gender viewpoints. I argue that Zhang's characterisation of Gong remodels heroine-hood in Chinese action films. Inheriting the typical plot of a daughter's use of martial arts for revenge for her father's death, Gong breaks from conventional Chinese action films that highlight romantic love during a woman's adventure and the decisive final battle scene. Beyond the propensity for sensory stimulation, Gong's characterisation enables Zhang to determine that women can really act in action films – demonstrating their inner power and ability to create multi-layered characters – not merely relying upon physical action. This chapter offers a relational perspective of how women transform the action film genre not merely as gender spectacles but as embodied figures that represent emerging female subjectivity.

To give a closed‐form solution of the relative pose determination problem based on monocular vision during final approach phase of spacecraft Rendzvous and Docking.

Based on the assumption of scaled orthographic projection, the model of perspective projection is simplified by representing the relative attitude using unit quaternion. Then a closed‐form solution is derived. Subsequently, this study correct the approximate solution to compensate the error caused by the assumption of scaled orthographic projection.

Extensive simulation studies were conducted for the validation of the proposed algorithm using Matlab™. When there are no relative attitudes between RVD spacecrafts, target distance for camera=2‐20 m. The simulation results show that the largest relative error of corrected relative position parameters is about 0.12 percent. When distance between RVD spacecrafts exceeds 5 m, the largest error of corrected relative attitude parameters are less than 0.3°. When the distance between spacecrafts are constant, the relative attitude parameters are changed, respectively, the simulition results show the largest relative error of relative position is 1 percent, and largest error of estimated relative attitude is 1.2°, when a relative attitude angle reaches 20°.

The proposed algorithm avoids the multiple results problem in determining the relative position and attitude parameters and the closed‐form solution is simple and effective, is more suitable for on‐board implementation.

Prior research has documented that managers take opportunistic timing activities to influence the exercise prices of executive stock options (ESOs). This paper aims to add to the literature by investigating whether such behavior is mitigated by the exercise price regulation of China.

Using a sample of 132 ESO reports between 2006 and 2010 in China, the authors explore whether the regulation takes effect by examining stock price movements and companies' information disclosures around the report dates.

Consistent with the conjecture that the regulation could not effectively limit managers' opportunistic behavior, the authors find that the abnormal returns decrease slowly until ten trading days before the report dates, increase gradually subsequently, and rise dramatically just after the report dates. Particularly, the return pattern is more pronounced when corporate governance is weaker. The authors also find that managers opportunistically time ESO reports based on their private information. In particular, more (less) favorable (negative) news announcements occur after the report dates than beforehand. Additionally, compared to earnings announcements, managers prefer to time ESO reports with information about forward‐looking earnings and security issuances.

These results suggest that the regulation could not effectively constrain managers from influencing the exercise prices. The paper also provides evidence that imperfect regulations under asymmetric information may lead to additional agency costs, especially when corporate governance is weak. The authors' findings can contribute to the improvement of regulations on ESOs.

China has showed its eagerness in using its economic strength in the very recent years. Is China going to be a major sanctioning state like the United States or the European Union? This chapter argues that although there have been an increasing number of economic sanctions imposed by China with its expanding national interests and growing diplomatic problems, China will still keep a low profile in using economic sanctions because of the restraining factors such as the WTO rules, inherent problems in its economy, the pursuit of a good reputation and its strategy of peaceful development. Thus the frequency and tactics of using economic sanctions may vary according to its rising economy and changing international situation, but that will go in a very limited way.

Doctors' labour and medicines are special necessities for human survival and evolution. Since China launched the healthcare reform, the theoretical circles' discussions have not yet clarified the respective special properties of doctors' labour and medicines as goods and the internal relations between doctors' labour and medicines at the level of the theoretical basis.

Health is a prerequisite for people's all-round development, a precondition for economic and social development and the people's common aspiration. The all-round moderately prosperous society could not be achieved without people's all-round health.

The authors believe the socialist relation between doctors' labour and medicines with Chinese characteristics should be one that is people-oriented, and the corporatization of hospitals or the capitalization of doctors' labour should be avoided.

In this paper, the authors explore the particularity of doctors' labour, particularity of medicine production, circulation, consumption and the internal relations between doctors' labour and medicines by using the analytical approach of Marxist political economy while considering the special roles of doctor's labour and medicines in the reproduction of labour power and put forward the theoretical basis for the segregation of doctor's labour and medicines.