Falcão Carneiro João, Bravo Pinto João, Gomes de Almeida Fernando, Cruz Nuno A
Instituto de Ciência e Inovação em Engenharia Mecânica e Engenharia Industrial, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal.
Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 400, 4200-465 Porto, Portugal.
Sensors (Basel). 2024 Sep 5;24(17):5771. doi: 10.3390/s24175771.
This paper introduces a new variable structure controller designed for depth control of an autonomous underwater sensor platform equipped with a variable buoyancy module. To that end, the prototype linear model is presented, and a finite element-based method is used to estimate one of its parameters, the hull deformation due to pressure. To manage potential internal disturbances like hull deformation or external disturbances like weight changes, a disturbance observer is developed. An analysis of the observer steady-state estimation error in relation to input disturbances and system parameter uncertainties is developed. The locations of the observer poles according to its parameters are also identified. The variable structure controller is developed, keeping energy savings in mind. The proposed controller engages when system dynamics are unfavorable, causing the vehicle to deviate from the desired reference, and disengages when dynamics are favorable, guiding the vehicle toward the target reference. A detailed analysis determines the necessary switching control actions to ensure the system reaches the desired reference. Finally, simulations are run to compare the proposed controller's performance with that of PID-based controllers recently developed in the literature, assessing dynamic response and energy consumption under various operating conditions. Both the VBM- and propeller-actuated vehicles were evaluated. The results demonstrate that the proposed controller achieves an average energy consumption reduction of 22% compared to the next most efficient PID-based controller for the VBM-actuated vehicle, though with some impact on control performance.
本文介绍了一种为配备可变浮力模块的自主水下传感器平台深度控制设计的新型变结构控制器。为此，给出了原型线性模型，并采用基于有限元的方法来估计其参数之一，即压力引起的船体变形。为了管理诸如船体变形等潜在内部干扰或重量变化等外部干扰，开发了一种干扰观测器。对观测器稳态估计误差与输入干扰和系统参数不确定性的关系进行了分析。还确定了观测器极点根据其参数的位置。在考虑节能的情况下开发了变结构控制器。所提出的控制器在系统动态不利导致车辆偏离期望参考时启动，而在动态有利时脱离，引导车辆朝向目标参考。详细分析确定了必要的切换控制动作，以确保系统达到期望参考。最后，进行了仿真，将所提出的控制器的性能与文献中最近开发的基于PID的控制器的性能进行比较，评估了各种运行条件下的动态响应和能量消耗。对采用可变浮力模块驱动和螺旋桨驱动的车辆都进行了评估。结果表明，对于采用可变浮力模块驱动的车辆，与次高效的基于PID的控制器相比，所提出的控制器平均能耗降低了22%，不过对控制性能有一定影响。
