A modified direct adaptive robust motion trajectory tracking controller of a pneumatic system
A modified direct adaptive robust motion trajectory tracking controller of a pneumatic system
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DOI：
10.1631/jzus.c1400003
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发表时间：
2014-10
期刊：
影响因子：
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通讯作者：
Pengfei Qian;Guoliang Tao;De-yuan Meng;Hao Liu
中科院分区：
文献类型：
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作者：
Pengfei Qian;Guoliang Tao;De-yuan Meng;Hao Liu
在这项研究中，我们开发并测试了一种高精度的气缸运动轨迹跟踪控制器，该控制器由四个无成本的开/关电磁阀驱动，而不是由比例方向控制阀驱动。通过实验确定了信号占空比的脉宽调制（PWM）与控制规律之间的关系，并建立了整个系统的数学模型。由于未知的扰动和未建模的动力学，该气动系统存在相当大的不确定非线性和参数不确定性。构建了改进的直接自适应鲁棒控制器（DARC）来解决这些问题。该控制器采用基于不连续投影映射的梯度型自适应律来保证估计的未知模型参数保持在已知有界区域内，并使用确定性鲁棒控制策略来削弱未建模动态、扰动和参数估计误差的影响。通过使用不连续投影映射，可以分别综合参数自适应律和鲁棒控制律。应用递归反步技术来解决无与伦比的模型不确定性。单独设计卡尔曼滤波器来估计运动状态和中间控制律的导数，以合成确定性鲁棒控制律。实验结果说明了所提出的控制器的有效性。
In this study, we developed and tested a high-precision motion trajectory tracking controller of a pneumatic cylinder driven by four costless on/off solenoid valves rather than by a proportional directional control valve. The relationship between the pulse width modulation (PWM) of a signal’s duty cycle and control law was determined experimentally, and a mathematical model of the whole system established. Owing to unknown disturbances and unmodeled dynamics, there are considerable uncertain nonlinearities and parametric uncertainties in this pneumatic system. A modified direct adaptive robust controller (DARC) was constructed to cope with these issues. The controller employs a gradient type adaptation law based on discontinuous projection mapping to guarantee that estimated unknown model parameters stay within a known bounded region, and uses a deterministic robust control strategy to weaken the effects of unmodeled dynamics, disturbances, and parameter estimation errors. By using discontinuous projection mapping, the parameter adaptation law and the robust control law can be synthesized separately. A recursive backstepping technology is applied to account for unmatched model uncertainties. Kalman filters were designed separately to estimate the motion states and the derivative of the intermediate control law in synthesizing the deterministic robust control law. Experimental results illustrate the effectiveness of the proposed controller.