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This paper aims to develop a specific type of mobile nonrigid support friction stir welding (FSW) robot, which can adapt to aluminum alloy trucks for rapid online repair.

The friction stir welding robot is designed to complete online repair according to the surface damage of large aluminum alloy trucks. A rotatable telescopic arm unit and a structure for a cutting board in the shape of a petal that was optimized by finite element analysis are designed to give enough top forging force for welding to address the issues of inadequate support and significant deformation in the repair process.

The experimental results indicate that the welding robot is capable of performing online surface repairs for large aluminum alloy trucks without rigid support on the backside, and the welding joint exhibits satisfactory performance.

Compared with other heavy-duty robotic arms and gantry-type friction stir welding robots, this robot can achieve online welding without disassembling the vehicle body, and it requires less axial force. This lays the foundation for the future promotion of lightweight equipment.

The designed friction stir welding robot is capable of performing online repairs without dismantling the aluminum alloy truck body, even in situations where sufficient upset force is unavailable. It ensures welding quality and exhibits high efficiency. This approach is considered novel in the field of lightweight online welding repairs, both domestically and internationally.

High-speed railway (HSR) substantially affects tourism development, but this impact remains somewhat controversial. This study aims to explore the HSR–tourism nexus from the perspective of Chinese local governance. In the context of promotion tournament model in China, this study attempts to explain such controversy by including local leaders.

Based on a data set from 25 cities in China’s Yangtze River Delta region during 2005–2019, this study uses a panel data regression model to examine local leaders’ moderating role in the HSR–tourism nexus.

The tenure of local leaders has a significant moderating role in the impact of HSR implementation on tourism development. Furthermore, a shorter leaders’ tenure strengthens the boost to tourism development from HSR service.

This paper enriches theoretical framework of leaders’ tournament theory. In addition, this study provides a new perspective to understand the HSR–tourism nexus better. This study identifies the moderating role of local leaders in the HSR–tourism nexus and expands the mechanism research of HSR–tourism nexus, which helps to explain the controversy of the HSR–tourism nexus.

高速铁路（HSR）对旅游业的发展有很大的影响, 但这种影响仍有一定的争议性。本研究从中国地方治理的角度探讨了高铁-旅游之间的关系。在中国晋升锦标赛模式的背景下, 本研究试图通过将地方领导纳入其中来解释这种争论。

基于2005-2019年中国长江三角地区25个城市的数据集, 我们利用面板数据回归模型来研究地方官员在高铁-旅游关系中的调节作用。

地方官员的任期在高铁开通对旅游业发展的影响中起着重要的调节作用。此外, 较短的官员任期会加强高铁连通对旅游业发展的促进作用。

本文丰富了官员锦标赛理论的理论框架。此外, 我们的研究为更好地理解高铁与旅游的关系提供了一个新的视角。我们确定了地方领导人在高铁-旅游关系中的调节作用, 拓展了高铁-旅游关系的机制研究, 有助于解释高铁-旅游关系的争论。

El tren de alta velocidad (TAV) afecta sustancialmente al desarrollo del turismo, pero este impacto sigue siendo algo controvertido. Este estudio explora el nexo entre el TAV y el turismo desde la perspectiva de la gobernanza local china. En el contexto del modelo de torneo de promoción en China, este estudio intenta explicar dicha controversia incluyendo a los líderes locales.

Basándonos en un conjunto de datos de 25 ciudades de la región china del delta del río Yangtze durante el periodo 2005-2019, utilizamos un modelo de regresión de datos de panel para examinar el papel moderador de los líderes locales en el nexo entre el TAV y el turismo.

El mandato de los líderes locales tiene un papel moderador significativo en el impacto de la implementación del TAV en el desarrollo del turismo. Además, un mandato más corto de los líderes refuerza el impulso al desarrollo turístico del servicio de TAV.

Este trabajo enriquece el marco teórico de la teoría del torneo de líderes. Además, nuestro estudio proporciona una nueva perspectiva para entender mejor el nexo entre el TAV y el turismo. Identificamos el papel moderador de los líderes locales en el nexo TAV-Turismo y ampliamos la investigación del mecanismo de dicho nexo, lo que ayuda a explicar la controversia del nexo.

The purpose of this paper is to enhance control accuracy, energy efficiency and productivity of customized industrial robots by the proposed multi-objective trajectory optimization approach. To obtain accurate dynamic matching torques of the robot joints with optimal motion, an improved dynamic model built by a novel parameter identification method has been proposed.

This paper proposes a novel multi-objective optimal approach to minimize the time and energy consumption of robot trajectory. First, the authors develop a reliable dynamic parameters identification method to obtain joint torques for formulating the normalized energy optimization function and dynamic constraints. Then, optimal trajectory variables are solved by converting the objective function into relaxation constraints based on second-order cone programming and Runge–Kutta discrete method to reduce the solving complexity.

Extensive experiments via simulation and in real customized robots are conducted. The results of this paper illustrate that the accuracy of joint torque predicted by the proposed model increases by 28.79% to 79.05% over the simplified models used in existing optimization studies. Meanwhile, under the same solving efficiency, the proposed optimization trajectory consumes a shorter time and less energy compared with the existing optimization ones and the polynomial trajectory.

A novel time-energy consumption optimal trajectory planning method based on dynamic identification is proposed. Most existing optimization methods neglect the effect of dynamic model reliability on energy efficiency optimization. A novel parameter identification approach and a complete dynamic torque model are proposed. Experimental results of dynamic matching torques verify that the control accuracy of optimal robot motion can be significantly improved by the proposed model.

Sensorless passive lead-through programming (LTP) is a promising physical human-robot interaction technology that enables manual trajectory demonstrations based on gravity and friction compensation. The major difficulty lies in static friction compensation during LTP start-up. Instead of static friction compensation, conventional methods only compensate for Coulomb friction after the joint velocity exceeds a threshold. Therefore, conventional start-up external torques must overcome static friction. When the static friction is considerable, it is difficult for conventional LTP to start up and make small movements. This paper aims to decrease the start-up external torque and improve the small movement performance.

This paper reveals a novel usage of a high-gain position-loop in industrial robot applications aimed at sensitively detecting external torque during start-up. Then, the static friction is partly compensated by Coulomb friction to facilitate start-up. In addition, a detailed transition method between the proposed start-up and conventional passive LTP is proposed based on a finite state machine.

Experiments are implemented on the ROKAE XB4 robot to verify the effectiveness of the proposed external torque detection. Compared with the conventional LTP method, the proposed LTP method significantly decreases the start-up external torque and facilitates small movements.

This paper proposes and verifies a novel start-up method of sensorless LTP based on a start-up external torque detection and a transition method between start-up and conventional LTP. This research improves the LTP start-up performance, especially for industrial robots with large static friction.

The purpose of this paper is numerical calculation of total electric field in oil-paper insulation. Now, there is no effective method to consider the influence of space charges when calculating the total electric field distribution in the main insulation system of the valve-side winding of an ultra-high-voltage direct current converter transformer.

To calculate the total electric field in an oil-paper insulation system, a new simulation method in single-layer oil-paper insulation based on the transient upstream finite element method (TUFEM) is proposed, in which the time variable is considered. The TUFEM is used to calculate the total electric field in an oil-paper insulation system by considering the move law of space charges. The simulation method is verified by comparing the simulation results to the test data. The move law of space charges and distribution characteristics of the electric field under difference voltage values in single-layer oil-paper insulation were presented.

The results show that the TUFEM has an excellent accuracy compared with the test data. When carrier mobility is a constant, the time to reach the steady state is inversely correlated with the initial electric field intensity, and the distortion rate of the internal total electric field is positively correlated with the initial electric field intensity.

This paper provides an exploratory research on the simulation of space charge transport phenomenon in oil-paper and has guiding significance to the design of oil-paper insulation.