曲柄滑块机构运动误差分析及其补偿控制研究

发布时间：2018-12-14 17:33

【摘要】：随着科学技术的飞速发展，传统的机械、仪器正在向着高速、重载、轻型、小型化和精密化的方向发展。高质量、高效率的机械和仪器对其动态精度提出了越来越高的要求。而在机械设备的设计、制造、安装、磨损和测量的过程中都会产生误差，机构的运动副中的间隙的存在是造成误差的重要原因。过大的间隙不仅大大地降低机构的运动精度，而且会引起运动副的冲击，出现过大的弹性变形，加速构件磨损，使间隙量变得更大，产生过大的噪声，降低机械效率。如果人为的减小间隙，这不仅会产生机构卡死的可能性，影响机器的使用寿命，，降低机器的可靠性，而且还增加了控制难度。因此,对于实际系统间隙的研究是非常有必要的。为了研究运动副间隙的存在对机构的稳定性产生的影响，本文分别采用了动力学分析和BP神经网络的方法,通过用Simulink仿真平台,以含间隙曲柄滑块机构为例建立了数学模型，并分别对其建立逆模型，在分析机构误差后分别进行了有逆模前馈的开环控制、PID加逆模前馈的闭环控制以及神经网络内模控制和模糊控制的方法来控制间隙带来的非线性误差。实验结果表明:含间隙机构由于间隙的存在，与理想机构的稳定性相比较差；用传统的动力学分析的方法建立的模型和用BP神经网络所建的模型相比，由于含间隙机构的强非线性，利用神经网络所建的模型更接近曲柄滑块机构的实际情况，仿真速度更快，结果更有意义；比起传统的有逆模前馈的开环控制、PID加逆模前馈的闭环控制，用神经网络内模控制和模糊控制两种智能控制更加有效的减小了间隙带来的非线性误差，使得系统的稳定性更高。
[Abstract]:With the rapid development of science and technology, traditional machinery and instruments are developing towards high speed, heavy load, light, miniaturization and precision. High-quality and high-efficiency machines and instruments require higher dynamic accuracy. In the process of design, manufacture, installation, wear and measurement of mechanical equipment, errors will occur, and the existence of clearance in the kinematic pair of the mechanism is an important cause of the errors. The excessive clearance not only reduces the motion accuracy of the mechanism greatly, but also causes the impact of the motion pair, causes the excessive elastic deformation, accelerates the wear of the components, makes the clearance quantity become larger, produces too much noise, and reduces the mechanical efficiency. If the gap is reduced artificially, it will not only lead to the possibility of mechanism jam, affect the service life of the machine, reduce the reliability of the machine, but also increase the difficulty of control. Therefore, it is necessary to study the actual system gap. In order to study the influence of the clearance on the stability of the mechanism, the dynamic analysis and the BP neural network are used in this paper. The mathematical model is established by using the Simulink simulation platform and taking the crank slider mechanism with clearance as an example. The inverse model is established, and the open-loop control with inverse mode feedforward is carried out after analyzing the error of the mechanism. PID with inverse mode feedforward closed-loop control and neural network internal model control and fuzzy control method to control the gap caused by nonlinear error. The experimental results show that the stability of the mechanism with clearance is worse than that of the ideal mechanism because of the existence of clearance. Compared with the model built by BP neural network, the model established by the traditional dynamic analysis method is closer to the actual situation of crank slider mechanism because of the strong nonlinearity of the mechanism with clearance. The simulation speed is faster and the result is more meaningful. Compared with the traditional open-loop control with inverse mode feedforward, the closed loop control with PID plus inverse mode feedforward is more effective in reducing the nonlinear error caused by the gap by using neural network internal model control and fuzzy control. Makes the system more stable.
【学位授予单位】：南华大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH112

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