| Power lithium battery is used as a core component of new energy vehicles, the assembly process mostly remains in the manual stage, low production efficiency, high error rate, the assembly precision is not up to the requirements, large labor intensity. This a series of problems restrict the new energy automobile production capacity and cost. This topic based on the actual project requirements, a new energy company in ShenZhen to develop a set of power lithium battery assembly line control system which can be 24 hours a day of stable and reliable work to realize the automation assembly of power lithium-ion battery pack.The system adopts distributed control system based on CAN bus which is divided into two layers: station field control layer(lower computer) and the production line management(IPC). In lower computer system, every station are both independent of each other and coordination, jointly completed assembly task of power lithium battery module; IPC system through the human-computer interaction interface is responsible for the production line in 2 minutes for a tact time synchronous operation, and controls production line system’s data acquisition, data analysis, fault diagnosis and error handing etc. Based on the production line control system hardware platform, the paper studies several key technologies. The specific work is as follows:In the issue of motion control strategy of power lithium battery pack assembly line, first of all, the lower computer manipulator uses fuzzy PID AC position servo system for each station, the control strategy combines with the flexible, adaptive characteristics of fuzzy control and conventional PID control’s characteristics of high precision, commonly improve dynamic and static characteristics of the control system; secondly, in the process of assembly, in order to ensure that each axis to start or stop without impact, out of step, overshoot or oscillation, S curve acceleration and deceleration algorithm is researched, which overcome the drawback of linear acceleration and deceleration algorithm. S curve’s running speed is very smooth, flexible degree is high, and is very suitable for high speed assembly; finally, from the perspective of linkage, using the eight direction linear interpolation to save time and improve efficiency, at the same time, the approximation of a given trajectory is more accurate.In distributed control system based on CAN bus, when the network load is large, CSMA/CD protocol only guarantees real-time transmission of high priority messages, low priority packets will fail in multiple competitive bus using right. This would lead to low priority message transmission causes uncertain delay, even appear the phenomenon that unable to send or exit the bus. Aiming at this problem, the paper studies the DMS algorithm and index partition EDF algorithm. Combined with the advantages of the two algorithms above, it presents a hybrid scheduling algorithm that through the TrueTime toolbox the simulation is carried out. The result shows that the hybrid algorithm guarantees on the basis of the real-time control system of the network, the system not only has high bandwidth utilization, but also reduces the consumption of system resources.Paper finally adopts the modular programming ideas to have a software design on production line control system. Through the cooperation of hardware and software, the whole system is in a state of normal operation at present. |
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