电弧焊接过程熔深PID自适应控制研究

Study on the PID Self-Adaptive Control for Penetration Depth of Arc-Welding Process

熔深是影响电弧焊接质量的重要因素。由于电弧焊接过程存在大惯性、大时滞等非线性特征以及不确定的干扰因素,熔深控制较为困难。为控制熔深,结合模糊逻辑,提出了一种电弧焊接过程熔深比例、积分、微分PID自适应控制策略,并建立了仿真试验系统。常规PID控制器具有较强的鲁棒性,而模糊PID(Fuzzy-PID)可在线改进常规PID控制器的比例、积分和微分控制参数,增强常规PID控制器的适应性。将模糊PID控制器和常规PID控制器并联,构成了电弧焊接过程熔深PID自适应控制策略,可自适应调节2个控制器的输出,以控制电弧焊接过程熔深。仿真结果表明,与常规PID、并联PID以及Fuzzy-PID控制策略相比,该熔深PID自适应控制策略的给定值跟踪和干扰抑制性能更优,具有更好的控制效果,可进一步应用于实践。

The penetration depth is an important factor related to the quality of arc-welding. For nonlinear characteristics of large inertia,large time delay and uncertain disturbance factors in the arc-welding process, it is difficult to control the penetration depth. In order to control the penetration depth, combining with fuzzy logic, a novel penetration depth PID self-adaptive control strategy for arc-welding process is put forward, and a simulation experiment system is established. The conventional PID controller features strong robustness, while Fuzzy-PID can improve the proportion, integral and differential control parameters of the conventional PID controller online, to enhance the adaptability of the conventional PID controller. By parallel connecting the Fuzzy-PID controller and the conventional PID controller, the penetration depth PID adaptive control strategy for arc-welding process is formed, and the outputs of two controllers are adaptively adjusted to control the penetration depth of arc welding process. The results of simulation show that compared with conventional PID, parallel PID, and Fuzzy-PID control strategies, a better control performance of penetration depth in set-point tracking and interference suppression disturbance is achieved by the proposed strategy, this novel PID self-adaptive control strategy can be further applied in practice.