Stabilizing unstable operating points is an effective way to enhance process benefits and safety, which motivates the development for a variety of advanced control strategies. The washout filter-aided controller(WFC),...Stabilizing unstable operating points is an effective way to enhance process benefits and safety, which motivates the development for a variety of advanced control strategies. The washout filter-aided controller(WFC), originally used for electric power system and aircraft, has been introduced to adjust the dynamic behavior of chemical process. However, the parameter tuning method faces two major limitations: the dimension of operating variables must be equal to or greater than that of state variables and only one positive real eigenvalue exists in the open loop system. To overcome the two limitations, this paper proposes a new parameter tuning method, so that the WFC is applicable in most chemical processes. By solving a constrained optimization problem, the controller parameters are determined under the constraint that the reassignment of the eigenvalues of the unstable desired operating point can satisfy the stability condition. Thus parts of the equilibrium manifold including the desired operating point are stabilized without affecting the shape of the equilibrium manifold. Finally, the effectiveness of the WFC improved by the proposed parameter tuning method is illustrated through a case study for propanediol anaerobic fermentation.展开更多
除了降低用户的听觉效果和佩戴舒适度外,数字助听器中的回声也很容易形成啸叫,从而导致系统的不稳定。为了保持自适应算法的收敛速度与稳态误差之间的平衡,研究了助听器中的回声消除模型和自适应回声消除算法,并提出了一种改进的归一化...除了降低用户的听觉效果和佩戴舒适度外,数字助听器中的回声也很容易形成啸叫,从而导致系统的不稳定。为了保持自适应算法的收敛速度与稳态误差之间的平衡,研究了助听器中的回声消除模型和自适应回声消除算法,并提出了一种改进的归一化最小均方(normalized least mean square,NLMS)算法。该方法引入误差信号自动调整步长因子,以加快滤波器收敛和降低稳态误差。仿真结果表明,改进算法在回声消除方面表现出更好的性能。通过比较算法的均方误差(mean square error,MSE)曲线,改进算法具有更好的收敛速度和稳态误差,平均均方误差比NLMS算法低4.01 dB。改进后的NLMS算法性能良好,耗时相对较短,易于实现。展开更多
基金Supported by the National Basic Research Program of China(2012CB720500)the National Natural Science Foundation of China(21306100)
文摘Stabilizing unstable operating points is an effective way to enhance process benefits and safety, which motivates the development for a variety of advanced control strategies. The washout filter-aided controller(WFC), originally used for electric power system and aircraft, has been introduced to adjust the dynamic behavior of chemical process. However, the parameter tuning method faces two major limitations: the dimension of operating variables must be equal to or greater than that of state variables and only one positive real eigenvalue exists in the open loop system. To overcome the two limitations, this paper proposes a new parameter tuning method, so that the WFC is applicable in most chemical processes. By solving a constrained optimization problem, the controller parameters are determined under the constraint that the reassignment of the eigenvalues of the unstable desired operating point can satisfy the stability condition. Thus parts of the equilibrium manifold including the desired operating point are stabilized without affecting the shape of the equilibrium manifold. Finally, the effectiveness of the WFC improved by the proposed parameter tuning method is illustrated through a case study for propanediol anaerobic fermentation.
文摘除了降低用户的听觉效果和佩戴舒适度外,数字助听器中的回声也很容易形成啸叫,从而导致系统的不稳定。为了保持自适应算法的收敛速度与稳态误差之间的平衡,研究了助听器中的回声消除模型和自适应回声消除算法,并提出了一种改进的归一化最小均方(normalized least mean square,NLMS)算法。该方法引入误差信号自动调整步长因子,以加快滤波器收敛和降低稳态误差。仿真结果表明,改进算法在回声消除方面表现出更好的性能。通过比较算法的均方误差(mean square error,MSE)曲线,改进算法具有更好的收敛速度和稳态误差,平均均方误差比NLMS算法低4.01 dB。改进后的NLMS算法性能良好,耗时相对较短,易于实现。
