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In customized production such as plate workpiece grinding, because of the diversity of the workpiece shapes and the positional/orientational clamping errors, great efforts are taken to repeatedly calibrate and program the robots. To change this situation, the purpose of this study is to propose a method of robotic direct grinding for unknown workpiece contour based on adaptive constant force control and human–robot collaboration.

First, an adaptive constant force controller based on stiffness estimation is proposed, which can distinguish the contact of the human hand and the unknown workpiece contour. Second, a normal vector search algorithm is developed to calculate the normal vector of the unknown workpiece contour in real-time. Finally, the force and position are controlled in the calculated normal and tangential directions to realize the direct grinding.

The method considers the disturbance of the tangential grinding force and the friction, so the robot can track and grind the workpiece contour simultaneously. The experiments prove that the method can ensure the force error and the normal vector calculating error within 0.3 N and 4°. This human–robot collaboration pattern improves the convenience of the grinding process.

The proposed method realizes constant force grinding of unknown workpiece contour in real-time and ensures the grinding consistency. In addition, combined with human–robot collaboration, the method saves the time spent in repeated calibration and programming.

Compared with other related research, this method has better accuracy and anti-disturbance capability of force control and normal vector calculation during the actual grinding process.

Aircraft structures are mainly connected by riveting joints, whose quality and mechanical performance are directly determined by vertical accuracy of riveting holes. This paper proposed a combined vertical accuracy compensation method for drilling and riveting of aircraft panels with great variable curvatures.

The vertical accuracy compensation method combines online and offline compensation categories in a robot riveting and drilling system. The former category based on laser ranging is aimed to correct the vertical error between actual and theoretical riveting positions, and the latter based on model curvature is used to correct the vertical error caused by the approximate plane fitting in variable-curvature panels.

The vertical accuracy compensation method is applied in an automatic robot drilling and riveting system. The result reveals that the vertical accuracy error of drilling and riveting is within 0.4°, which meets the requirements of the vertical accuracy in aircraft assembly.

The proposed method is suitable for improving the vertical accuracy of drilling and riveting on panels or skins of aerospace products with great variable curvatures without introducing extra measuring sensors.

It is very common that most product assemblies in industry require two mating parts where one must fit into the other. However, we may observe interference if the shaft does not fit within or over the shaft, or we may experience excessive clearance. In calculating the percentage of interference or excessive clearance, most industries usually assume normal distribution for quality characteristics of mating parts and use a distribution of their difference to analyze the interference or clearance. However, it has not been proved that the collected data matches the assumption of normality. Therefore, it is doubtful that the calculated nonconforming rate truly reflects the performance of the assembly process. This research focuses on the clearance and interference analysis for the non‐normal data of product assembly. Comparisons have also been made between actual nonconforming rate and the assumed normal percentage of nonconformance by overlooking their theoretical distributions of two mating parts. Finally, a computer program has been proposed to simplify tedious calculation process for estimating the nonconforming rate under non‐normal distribution.

Every geometric model corresponding to a unique feature whose errors of parameters uncorrelated, so the linearization technique can be successfully applied. The solution of a linear least square problem can be applied straightforwardly. This method has advantages especially in calibrate the redundant robot because it’s relatively small. The parameters of kinematics are unique and determined by this algorithm.

In this paper, a geometric identification method has been studied to estimate the parameters in the Denavit–Hartenberg (DH) model of the robot. Through studying the robot’s geometric features, specific trajectories are designed for calibrating the DH parameters. On the basis of these geometric features, several fitting methods have been deduced so that the important geometric parameters of robots, such as the actual rotation centers and rotate axes, can be found.

By measuring the corresponding motion trajectory at the end-effector, the trajectory feature can be identified by using curve fitting methods, and the trajectory feature will reflect back to the actual value of the DH parameters.

This method is especially suitable for rigid serial-link robots especially for redundant robots because of its specific calibration trajectory and geometric features. Besides, this method uses geometric features to calibrate the robot which is relatively small especially for the redundant robot comparing to the numerical algorithm.

In the first part of this series of papers on the combined finite/discrete element simulation of shot peening processes, different contact interaction laws for 2D cases are extensively studied with special attention given to the proper selection of the parameter values involved, which is one of the key issues for successful direct simulation. In addition, computational issues including contact forces, partial contact, energy dissipation, and rheological representation are addressed. Numerical examples for a single shot impact system simulated by the coupled finite/discrete element method using different interaction laws are provided to verify the proposed approaches. The results are also compared with those obtained by using only finite element methods. Findings obtained by performing 2D simulations will, in the subsequent article, be used in realistic computational simulations of 3D shot peening processes.

A FEATURE of many of the light alloys now in common use is that the stress and strain curve often does not evidence any well defined region in which the elastic strain becomes plastic strain, and a linear portion of the diagram from the origin, which in the case of so many metals represents a region of proportionality, is sometimes almost non‐existent, the diagram being curved right from the origin so that it is not possible to define any region or limit of proportionality, and the proof stress; by standard definition, has accordingly a relatively low value compared with the ultimate tensile stress of the alloy concerned. (Fig. 1).

More and more statistics have repeatedly shown that as the economic development has entered the New Normal, the Chinese fiscal system has experienced tremendous changes. Although chance cannot be ruled out, much of those changes indicate trends, and they can even be said to be the result of the law of economic development. These trends and changes have repeatedly demonstrated that, as a reflection and an inevitable result of the economic developing speed shift, structural adjustment and energy conversion, the Chinese fiscal system, far from the conventional operating state, has progressed on a new path. The paper aims to discuss this issue.

This paper systematically analyzes several new trends and changes in the Chinese fiscal system under the New Normal. First, revenue growth has experienced a sharp downward trend, while the tax elasticity coefficient has declined rapidly. Second, fiscal expenditure has risen against the tendency, while the rigidity of expenditure has kept on increasing.

Considering the present fiscal and taxation system reform with the analysis above, it can be seen that if the reform’s progress for the past two years is slower than expected – thus, preventing the effects of all aspects from a timely achievement – then, in the recent period, the agreement on the fiscal and taxation system reform will be reached and challenges entirely different from the past, including sharp slowdown in revenue growth rate, fiscal expenditure rising against trend and increases in fiscal deficit and government debts will be faced. The factors encouraging the reform are gathering gradually. The growth of the strength to push the reform forward is speeding up. And the pace of the reform in relevant areas is quickening.

In the face of those trends and changes, on the one hand, the authors should deeply understand and accurately grasp them through a comprehensive summary and systematic analysis. On the other hand, a series of conventional ideas, thoughts and strategies should be adjusted comprehensively and duly. Taking a train of new ideas, thoughts and strategies, the authors ought to actively adapt to and initiate a new Chinese fiscal structure under the New Normal of China’s economy.

The highly contagious coronavirus and the rapid spread of COVID-19 disease have generated a global public health crisis, which is being addressed at various local and global scales through social distancing measures and guidelines. This is coupled with debates about the nature of living and working patterns through intensive utilisation of information and telecommunication technologies, leading to the social and institutional acceptability of these patterns as the “new normal”. The primary objective of this article is to instigate a discourse about the potential contribution of architecture and urban design and planning in generating knowledge that responds to pressing questions about future considerations of post pandemic architecture and urbanism. Methodologically, the discussion is based on a trans-disciplinary framework, which is utilised for conceptual analysis and is operationalized by identifying and discoursing design and planning implications. The article underscores relevant factors; originates insights for areas where future research will be critically needed, through key areas: a) Issues related to urban dynamics are delineated from the perspective of urban and human geography, urban design and planning, and transportation engineering; b) Questions that pertain to socio-spatial implications and urban space/ urban life dialectics stem from the field of environmental psychology; and c) Deliberations about new environments that accommodate new living/working styles supervene from ethnographical and anthropological perspectives. The article concludes with an outlook that captures key aspects of the needed synergy between architectural and urban education, research, and practice and public health in a post pandemic virtual and global world.

This study aims to examine the use of real activities manipulation by firms implicated in the stock option backdating scandal.

The real activity manipulation measures are as follows: abnormal R&D expense, abnormal SG&A expense, abnormal production cost and abnormal cash flow from operations. Using a sample of firms alleged to have backdated options during the period 1998-2006 and non-backdating one-on-one matched firms, a separate regression is run for each of the real activity manipulation measures (dependent variables) on backdating and other variables.

The authors report unusually low R&D and unusually low SG&A expenses among the backdating firms. They also find evidence of unusually high production costs among backdating firms compared to the matched firms.

The findings imply that backdating firms are more aggressive in the use of real activities to manipulate earnings and the use of real activities appears to be opportunistic.

The study contributes to the literature by providing evidence of the use of real activities manipulation by firms under investigation for fraud. The authors also add to the debate on whether the use of stock options as part of compensation aligns the interest of management with the interest of shareholders.

This article considers the issues raised by the proposed abolition of the mandatory retirement age as a result of the Equal Treatment Directive, 2000/78/EC, and of proposed Age Discrimination in Employment Regulations. It argues that there are a number of distinctive retirement ages, namely, the contractual retirement age, the pensionable retirement age and the actual or normal retirement age. These may coincide or they may occur at different times, but it is only the contractual retirement age that is likely to be abolished by the Regulations. Their effect upon the retirement age will therefore be limited. As part of the research for this article a number of TUC affiliated trade unions were interviewed in order to gain an employee perspective of the issues surrounding the abolition of mandatory retirement ages.