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This paper presents a new approach to coupling line balancing and buffer allocation for stochastic mixed-model assembly line. Three types of complexity are defined, that are time diversity complexity for single station, time diversity complexity for a whole line, and time stochastic fluctuations complexity. An integrated optimization model for line balancing and buffer allocation is established with the objectives of maximizing productivity, minimizing complexity and total buffer capacity. Then an improved genetic algorithm is applied to solve the model. Finally, the effectiveness of the method is verified by an example of a mixed-model assembly line.

The battery charging strategy of automation guided vehicles (AGVs) is playing an important role in improving the utilization of AGVs. This paper proposes two dual-stage battery charging strategies of AGVs, which equip with lithium-ion battery for improving the utilization. In stage 1, two routing decisions based on heuristic algorithm are developed, namely the nearest charging station (NCS) and the minimum delay charging station (MDCS); while in stage 2, the duration of each charging occurrence is reduced considering the charging characteristic of lithium-ion battery. A real case is adopted to illustrate the applicability and effectiveness of the proposed approach.

According to the problem of trajectory planning for collaborative welding robot with multiple manipulators which is applied in dual-beam laser welding of aircraft double curved panel, the multi-manipulator kinematics model is constructed based on Devanit-Hartenberg (D-H) method, and the solution of inverse kinematics is deduced through the specific algebraic method. In addition, the motion law of each joint variable is obtained on the basis of the trajectory planning method for the continuous path. Finally, the correctness of inverse kinematics algorithm and the effectiveness of trajectory planning for the modified robot are verified by ADAMS simulation.

A collaborative welding platform consists of a XYZ-mobile truss, a 3R (revolute joint) clamping robot and a dual-arm welding robot. Based on Denavit-Hartenberg (D-H) method, the analytical inverse kinematics solution of the platform is obtained. Dual-arm coordination is a technical difficulty in robot control field. Focusing on self-collision problem during dual-arm robot motion planning, this paper proposes a new obstacle avoidance algorithm based on Rapidly Exploring Random Tree (RRT) algorithm. Setting searching area founded on artificial potential field (APF) algorithm and adopting note-pruning strategy achieves high searching efficiency. Simulation results verify the correctness of kinematics analysis and self-collision detection algorithm.

In this paper, we present a preventive condition-based maintenance (CBM) policy with imperfect maintenance actions. This model not only includes the continuous degradation caused by usage but also the instantaneous degradation due to the random shocks. Moreover, the remaining useful life (RUL) is introduced into the maintenance policy. Based on the estimated RUL, the degradation level at the next inspection moment is adapted to schedule the preventive maintenance action at the current inspection moment. At last, a numerical example is presented to get the minimum maintenance cost per unit of time and a simulation model is analyzed.

This paper proposes a modeling and evaluation method for structural vulnerability of manufacturing system based on universal generating function and information entropy principle. Considering the influence of the buffer states, the actual state and probability distribution of each machine is calculated. The series and parallel composite operators are introduced to solve the generation function of the whole system, and the state space and its corresponding probability space are obtained. Then, the system structural vulnerability model is established according to the information entropy. Finally, the effectiveness of the model and evaluation method are validated on a flexible production line.