Design and simulation of assembly systems with mobile robots

This paper proposes an approach to the design and operation of assembly systems that include mobile robots. It is based on a semantic model representing the robot/resource skills along with the operations that a resource has to execute. The method is implemented in a system capable of generating the assignment of operations to the proper robotic resources. Collision free paths can be generated for the assembly system robots with the help of simulation. The method is presented in a case study from the automotive industry.     

A priori calculations of adsorption equilibria in ternary systems

The article describes the procedure for a priori calculations of the equilibrium properties of the adsorption of ternary solutions based on experimental data for corresponding binary solutions. The calculation is based on a method developed previously by the authors that facilitates the highly accurate determination of the equilibrium activities of components in ternary volumetric solutions as a function of the predetermined composition of an adsorbed solution.     

Self-optimizing assembly of laser systems

Laser assembly can be a tedious task if performed manually. Especially if miniaturization of the laser is desired, robot-based assembly can greatly improve quality, performance and throughput, while self-optimization is regarded as a strategy to reduce planning efforts and increase the robustness of the assembly. An automated laser assembly system has been developed together with a concept to increase the autonomy through a multi-agent system control structure. The multi-agent system allows assembly steps like sequence planning, measurement of components and deviations, selection of components, soldering elements onto a carrier plate and active resonator alignment to be handled by the system itself and enables the assembly system to uniquely plan every laser system and execute its assembly within a flexible robot-based assembly cell.     

A parametric study of joint performance in sheet metal assembly

In sheet metal assembly, joints are designed to facilitate welding the parts and to form various shapes and dimensions of sheet metal products. The most commonly used joints are lap joints, butt joints and butt-lap joints. Different joint configurations have different performance characteristics. One of the performance criteria is the level of dimensional variation in the assembly. This paper presents a parametric study of the dimensional variation characteristics of the three basic joints. An offset finite-element-model-based variation simulation methodology is used in the parametric study in order to take into consideration possible part deformation. This parametric study helps determine the circumstances under which part variation or tooling variation will contribute more variation to assembly variation. These results provide improved understanding of sheet metal assembly processes and provide data for robust product/process design.     

Modeling assembly systems with repetitive operations

Two methods are presented to model assembly systems where repetitive operations are integrated in one single machine following strictly planned sequences. The first method introduces an aggregate machine to approximate the original repetitive assembly machine so that the aggregate machine and the original machine have equivalent behaviors on processing time, machine reliability and maintainability. The second method transforms the repetitive assembly operations into a series of synchronized assembly/disassembly models so that the traditional assembly model can be applied to analyze such repetitive assembly machines. We systematically compare the accuracy of those two new models with that of a simulation model.     

In-mould assembly of functionally integrated structures: A surrogate model for fast quality assessment

For the in-mould assembly of functionally integrated structures, a proper bond strength development between the different components has to be ensured during the actual manufacturing step. Physically detailed models and simulations are able to compute a reliable bond strength distribution. However, these computations are very time consuming. In this contribution, a simulation based surrogate model for the in-mould assembly of thermoplastic composite structures is developed. It predicts the bond strength within seconds using data from process simulations combined with machine learning, achieving a remaining error of less than 5% compared to high-fidelity computations.     

基于一种简单时域方法的滚动轴承性能退化评估

滚动轴承是一种最常用的机械设备,其性能退化评估是实现CBM(视情维修)的基础。但要找到一种具有可靠性好、效率高和故障预警早的滚动轴承监测系统是一个重大的挑战。提出了一种简单新颖的轴承性能退化评估时域方法,并将其运用于在滚动轴承故障模拟试验和全寿命测试实验,两种实验结果都表明:所提出方法能够清晰地描述故障程度变化趋势并能检测早期故障。     

汽车总装线上远程激光焊接能量评估

通过分析激光源的类型和结构,建立参数数据库,并结合机器人运动的动力学分析,本研究提出了汽车总装线上远程激光焊接(RLW)的能量评估模型。通过对简单焊件进行焊接实验,将传统激光焊接和远程激光焊接进行了对比,结果发现,焊接过程中机器人运动能量逐渐减少,而激光能量逐渐增加。处理时间和激光功率是影响远程焊接能源效率的主要因素。     

Process and performance optimization by selective assembly of battery electrodes

The increasing demand for electric vehicles and thus lithium-ion batteries results in a multitude of challenges in production technology. The reproducibility and performance of large scale batteries for automotive applications are very high. At the same time the production processes are complex and involve many uncertainties. Two essential process steps are the electrode coating and electrode package assembly. The mass loading of anodes and cathodes are determined by the coating process, where deviations can be caused by different reasons. The selective assembly of the electrodes is a reasonable way to balance the production variances. The contribution shows extended algorithms and their benefits and drawbacks of matching electrodes in order to improve the subsequent electrode packaging process. Here, the aim is to reach higher cell capacities and optimized performance values by “optimally” balanced electrodes regarding the mass loading ratio, which is also related to the specific material capacity.     

Human and robot allocation method for hybrid assembly systems

Manufacturing companies today need to increase both changeability and efficiency of production systems in order to strengthen their competitiveness. Hybrid assembly systems have evolved as solutions to counter this issue. In this system, humans and robots cooperate to perform assembly tasks; the system has the advantage of maximizing robot efficiency and human flexibility. This paper proposes a method for planning human and robot allocation in hybrid assembly systems. The method enables us to select the initial human and robot allocation, that minimizes the expected total production cost including robot investment and labor cost taking into consideration possible scenarios of future changes in product models and production volumes.     

移动焊接机器人控制性能评价方法研究

基于混合动力系统驱动的移动焊接机器人是一个非线性、强耦合的系统,控制参数对系统的控制特性影响不同。为改善焊接机器人的控制特性,有必要研究一种评价方法来探讨这些参数对系统的影响程度。系统的控制特性主要包括:运行性、稳定性、经济性三个方面。基于移动焊接机器人的综合评价模型,提出了一种结合信息熵和核主成分分析的综合评价方法。信息熵用于建立系统综合评价模型,核主成分分析将数据线性化并降维。研究结果表明,在保证系统信息量的基础上,该方法能较好地处理和分析各种指标数据之间的非线性关系,减少综合评价分析处理的数据量,可以提高焊接机器人系统的综合评价效率。     

Product modularity and assembly systems: An automotive case study

Designing modular products offers a number of advantages. However, modularity may be challenging in terms of production and assembly. In this paper, the influence of product design modularity on assembly systems is investigated. A modular design from the automotive industry is presented and compared with a traditional design. The influence of modularity on the assembly system is discussed including attributes such as production rate, investment cost and product's delivery delay.     

Product variety and manufacturing complexity in assembly systems and supply chains

Mixed-model assembly systems and modular supply chains are enablers to high product variety. However, as variety gets very high, the assembly and supply processes can become very complex. In assembly systems, the complexity may cause human errors and in turn impacts system performance. The complexity also impacts supply chain configuration and inventory control policy. This paper proposes a unified measure and models of complexity to assist in designing systems with robust performances. Complexity is defined as an entropy function of product variety and models are developed to describe the complexity propagation in multi-stage assembly systems and multi-echelon supply chains. Applications of the models are presented for complexity mitigation.     

Design and development of automatic systems for assembly welding muffler of Santana automobile

ＤｅｓｉｇｎａｎｄｄｅｖｅｌｏｐｍｅｎｔｏｆａｕｔｏｍａｔｉｃｓｙｓｔｅｍｓｆｏｒａｓｓｅｍｂｌｙｗｅｌｄｉｎｇｍｕｆｆｌｅｒｏｆＳａｎｔａｎａａｕｔｏｍｏｂｉｌｅＨＥＤｅｆｕ；ＹＵｈａｉｌｉａｎｇ；ＴＡＮＧＸｉｎｈｕａ；ＷＡＮＧＳｉｚｕｏａｎｄＺｈ...     

Lining installation and performance in FGD systems

Availability and reliability of pollution control equipment have become important issues in recent years. Critical components such as scrubbers, ductwork, tanks, and stacks must be protected to withstand the corrosive environments that are characteristic for pollution control systems. Monolithic linings have been applied successfully in many flue gas desulfurization (FGD) systems. More than 4 million m² of installed linings protect critical steel structures in pollution control to ensure high percentages of plant operation availability. Flake lining systems represent the most extensively used class of materials for materials for FGD linings for ducts, scrubbers, and stacks. Experiences with this type of material, which can be applied either by trowel or spraygun, date back to 1967 in the United States and 1978 in Europe.     

Determination of extended availability and productivity for assembly systems using existing data base

Reliable information about the operational availability of assembly or production systems is of great importance for the users of complex production facilities, especially when such facilities operate at their capacity limit. Nowadays, in most cases, the availability of assembly systems is monitored and evaluated using collected status data. This paper presents a new approach for permanent productivity determination of assembly systems based on the usage of in-process acquired product data. This approach is especially applicable for manufacturing systems that produce goods for which complete product traceability is required.     

Development of new concepts and software tools for the optimization of manual assembly systems

Due to growing numbers of differing products and variants, assembly systems with optimized manual workstations have become an efficient alternative to highly automated but less flexible production systems. Especially in the final stage of the product assembly, the flexibility of human employees enables them to meet the requirements for assembling various products and changing volumes. In order to create highly efficient production systems based on human work, it is necessary to develop innovative concepts for the design and organization of manual assembly structures. Another major issue is the development of software tools allowing the facility planner to simulate and optimize the complete design of the assembly structure such as the material flow or manual workstations, e.g. with respect to ergonomics, before construction. These requirements have led to a comprehensive research framework for manual assembly systems.