Research on the Orientation Error of the Translational Cable-Driven Parallel Robots

Parallel cables are gradually widely used in cable-driven parallel robots (CDPR) to provide constraints to the end effector and to realize translational degrees of freedom. However, when there are dimensional errors, parallel cables become no longer parallel and will cause terminal attitude errors, which can’t be compensated by kinematic calibration. In this paper, the attitude assurance method is studied considering a three DOFs translational CDPR. Firstly, the kinematic model and error mapping model of the robot is established by using the closed-loop method, considering the pulley radius. Secondly, the influence of the dimensional parameter errors on the terminal error is analyzed with the sensitivity index, which establishes a theoretical basis for the simplification of the accuracy synthesis process. Thirdly, the design tolerances of the cable connection points are determined through accuracy synthesis, which is implemented with the genetic algorithm considering the optimal manufacturing cost and ensure the attitude accuracy of the end effector. Finally, to reduce the influence of cable length error, the method of adjusting the initial pose was proposed and studied, which is verified as an effective approach.

Wind Farm Cable Connection Layout Optimization with Several Substations

Green energy has become a media issue due to climate changes, and consequently, the population has become more aware of pollution. Wind farms are an essential energy production alternative to fossil energy. The incentive to produce wind energy was a government policy some decades ago to decrease carbon emissions. In recent decades, wind farms were formed by a substation and a couple of turbines. Nowadays, wind farms are designed with hundreds of turbines requiring more than one substation. This paper formulates an integer linear programming model to design wind farms’ cable layout with several turbines. The proposed model obtains the optimal solution considering different cable types, infrastructure costs, and energy losses. An additional constraint was considered to limit the number of cables that cross a walkway, i.e., the number of connections between a set of wind turbines and the remaining wind farm. Furthermore, considering a discrete set of possible turbine locations, the model allows identifying those that should be present in the optimal solution, thereby addressing the optimal location of the substation(s) in the wind farm. The paper illustrates solutions and the associated costs of two wind farms, with up to 102 turbines and three substations in the optimal solution, selected among sixteen possible places. The optimal solutions are obtained in a short time.

The design of thermal aging camera for observing thermal map during electrical installation practical

Many cases of fire due to electrical short circuit facilities or inadequate electrical maintenance, require technology in the field of preventive maintenance. Educational materials and knowledge regarding the prevention and handling of damage and the dangers resulting from abnormal heat, must be taught in the practice class, in particular the electrical installation practice. The use of photo infrared thermography to analyze the distribution of excess heat (overheating) at the cable connection points and the constituent electrical components is a new necessity. The still expensive thermal camera led to an inexpensive prototype but still had the same result. The infrared camera prototype was made from the M5Stack microcontroller module and the AMG8833 infrared thermal sensor. The camera was used to check the heat patterns that occured in electrical and mechanical equipment during the operation. The temperature data recorded from the AMG8833 sensor were in the form of an array of data measuring 8x8 pixels which then were proceeded using an interpolation technique to get an even bigger size, 64x64 pixels. The temperature data were presented in a form of certain colors which represented the measured temperature. The prototype results were compared with the standard HT-02 thermal camera resulting in 0.001% of error.

Investigation of Thermal Stability of 0.6/1 kV Metal-Coated Carbon Fiber Cable and Joint

For this paper, we manufactured the 0.6/1 kV 3-core cable using metal-coated carbon fiber (MCF), which can be utilized for a cable screen layer. This cable can be applied to non-earthed system, and has a shielding property of more than 90% of braiding density. However, new joints and methods are needed to connect the cables because carbon fiber has brittleness. Thus, the cable connection added a spring to the contact surface, reducing resistance and fiber brittleness. These cables and connection methods were evaluated for safety in a certain temperature, humidity and over-current environments. From the results, the change of the external shape and contact resistance of the cable and the joint against the humidity and temperature were not significant, and the insulation breakdown did not occur in the withstanding voltage property of 3.5 kV for 5 min. No thermal deformation of the cable and connections was observed at the current above the allowable current range; it can be used as stable as metal screen cable.

Cable Connection Optimization for Heterogeneous Offshore Wind Farms via a Voronoi Diagram Based Adaptive Particle Swarm Optimization with Local Search

Offshore wind energy, as one of the featured rich renewable energy sources, is getting more and more attention. The cable connection layout has a significant impact on the economic performance of offshore wind farms. To make better use of the wind resources of a given sea area, a new method for optimal construction of offshore wind farms with different types of wind turbines has emerged in recent years. In such a wind farm, the capacities of wind turbines are not identical which brings new challenges for the cable connection layout optimization. In this work, an optimization model named CCLOP is proposed for such wind farms. The model incorporates both the cable capital cost and the cost of power losses associated with the cables in its objective function. To get an optimized result, a Voronoi diagram based adaptive particle swarm optimization with local search is proposed and applied. The simulation results show that the proposed method can help find a solution that is 12.74% outperformed than a benchmark.

METHODOLOGY FOR CALCULATING THE ECONOMIC EFFICIENCY OF CONNECTING END-USERS OF MESH WIRELESS NETWORKS TO THE GLOBAL NETWORK

This paper explores the cost-effectiveness of various ways to connect users to the Internet. Three methods are analyzed: cable connection, GSM connection and Wi-Fi mesh connection. For these methods, a mathematical model is constructed that allows you to evaluate: return on investment, company profits, risk fear ratios and regrets about lost profits. The indicated calculations are carried out for 100 users in each connection method. The study of economic efficiency will be carried out by assessing the values of the parameters NPV, PI and IRR. According to the classical approach to assessing the effectiveness of projects, when implementing projects in cities, a connection using Wi-Fi mesh networks has higher relative project performance indicators (PI and IRR), but a lower NPV indicator than a project for a cable connection to the Internet. In conditions of low population density, the project for the implementation of the Internet by Wi-Fi mesh networks is more profitable in all considered indicators (NPV, PI, IRR) than the project for the implementation of the Internet via cellular communication.