Stability Robustness of LQ and LQG Active Suspensions

1994 ◽  
Vol 116 (1) ◽  
pp. 123-131 ◽  
Author(s):  
A. G. Ulsoy ◽  
D. Hrovat ◽  
T. Tseng
Keyword(s):  
Controller Design ◽  
Active Suspension ◽  
Point Of View ◽  
Linear Quadratic ◽  
Linear Quadratic Gaussian ◽  
Active Suspensions ◽  
Quarter Car Model ◽  
Stability Robustness ◽  
Trade Offs ◽  
Two Degree Of Freedom

A two-degree-of-freedom quarter-car model is used as the basis for linear quadratic (LQ) and linear quadratic Gaussian (LQG) controller design for an active suspension. The LQ controller results in the best rms performance trade-offs (as defined by the performance index) between ride, handling and packaging requirements. In practice, however, all suspension states are not directly measured, and a Kalman filter can be introduced for state estimation to yield an LQG controller. This paper (i) quantifies the rms performance losses for LQG control as compared to LQ control, and (ii) compares the LQ and LQG active suspension designs from the point of view of stability robustness. The robustness of the LQ active suspensions is not necessarily good, and depends strongly on the design of a backup passive suspension in parallel with the active one. The robustness properties of the LQG active suspension controller are also investigated for several distinct measurement sets.

scholarly journals OPTIMAL CONTROLLER DESIGN FOR ACTIVE SUSPENSION SYSTEM ON CARS

2020 ◽  
Vol 225 (13) ◽  
pp. 107-113
Author(s):  
Vũ Văn Tấn
Keyword(s):  
Controller Design ◽  
Linear Quadratic Regulator ◽  
Active Suspension ◽  
Suspension System ◽  
Optimal Controller ◽  
Linear Quadratic ◽  
Linear Quadratic Gaussian

Hệ thống treo là một trong những bộ phận quan trọng nhất trong thiết kế ô tô và là yếu tố quyết định đến sự thoải mái của lái xe, hành khách (độ êm dịu) và giữ được bám giữa lốp và mặt đường (độ an toàn). Bài báo này giới thiệu một mô hình ¼ ô tô có 2 bậc tự do sử dụng hệ thống treo chủ động với hai bộ điều khiển tối ưu: linear quadratic regulator và linear quadratic gaussian (linear quadratic regulator kết hợp với bộ quan sát Kalman-Bucy). Bằng cách sử dụng bộ quan sát Kalman-Bucy, số lượng cảm biến dùng để đo đạc các tín hiệu đầu vào của bộ điều khiển linear quadratic regulator đã được giảm thiểu tối đa chỉ còn các cảm biến thông thường như gia tốc của khối lượng được treo. Độ êm dịu và an toàn chuyển động khi ô tô sử dụng hệ thống treo chủ động được so sánh với ô tô sử dụng hệ thống treo bị động thông thường thông qua dịch chuyển của khối lượng được treo và gia tốc của nó. Kết quả mô phỏng đã thể hiện rõ giá trị sai lệch bình phương trung bình của gia tốc dịch chuyển thân xe với hệ thống treo tích cực điều khiển tối ưu linear quadratic regulator, linear quadratic gaussian đã giảm khoảng 20% so với ô tô sử dụng hệ thống treo bị động.

scholarly journals Investigation on linear quadratic Gaussian control of semi-active suspension for three-axle vehicle

2020 ◽  
pp. 146134842096092
Author(s):  
Shaohua Li ◽  
Junwu Zhao ◽  
Zhida Zhang
Keyword(s):  
Active Suspension ◽  
Travel Speed ◽  
Vertical Vibration ◽  
Control Effect ◽  
Linear Quadratic ◽  
Linear Quadratic Gaussian ◽  
Analytic Hierarchy ◽  
Passive Suspension ◽  
On The Road ◽  
Weight Coefficients

An 8-DOF three-axle vehicle model with semi-active suspension is built in this paper, of which the accuracy is verified through simulations and experiments. Based on the optimal control theory, the linear quadratic Gaussian controller for semi-active suspension is designed with 10 evaluation indicators. Considering the deficiency of linear quadratic Gaussian control weight coefficients based on experience, analytic hierarchy process is employed to determine the weight coefficients of each indicator. The control effect is analyzed through MATLAB/Simulink. The adaptability of proposed control strategy under 25 driving conditions is analyzed with different road grades and speeds. The driving condition of “70 km/h travel speed on the road of grade B” is selected, under which the comparison of vehicle responses between semi-active suspension and passive suspension is made. Results show that the vertical vibration is effectively diminished by using semi-active suspension with linear quadratic Gaussian controller. Compared with passive suspension, the riding comfort is improved and the adverse effect on handling stability is eliminated. The three-axle vehicle with semi-active suspension has good adaptability to various working conditions.

Research on performance of vehicle semi-active suspension applied magnetorheological damper based on linear quadratic Gaussian control

2020 ◽  
Vol 51 (7-9) ◽  
pp. 119-126
Author(s):  
Shujing Sha ◽  
Zhongnan Wang ◽  
Haiping Du
Keyword(s):  
Active Suspension ◽  
Magnetorheological Damper ◽  
Optimal Feedback Control ◽  
Force Output ◽  
Linear Quadratic ◽  
Damping Force ◽  
Linear Quadratic Gaussian ◽  
Passive Suspension ◽  
Front Suspension ◽  
Suspension Model

With the development of automobile technology, the traditional passive suspension cannot meet people’s requirements for vehicle comfort and safety. For this reason, a variable damping semi-active suspension applied magnetorheological damper is proposed. By collecting various performance parameters of the front suspension, the optimal feedback control matrix is obtained by applying linear quadratic Gaussian control strategy, and the optimal damping force output is also obtained to improve comfort and vehicle safety by reducing vibration. The semi-active suspension model of a quarter vehicles was established by MATLAB/Simulink, and the simulation experiment was carried out. The results show that the semi-active suspension system with magnetorheological damper is superior to the traditional passive suspension in terms of vibration absorption; meanwhile, the root mean square values of vehicle acceleration, suspension dynamic deflection, tire dynamic travel, and tire dynamic load are reduced, which effectively improve the vehicle ride stability.

scholarly journals Attitude and Altitude Controller Design for Quad-Rotor Type MAVs

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Wei Wang ◽  
Hao Ma ◽  
Min Xia ◽  
Liguo Weng ◽  
Xuefei Ye
Keyword(s):  
Attitude Control ◽  
Controller Design ◽  
Sliding Mode ◽  
Micro Air Vehicles ◽  
Triaxial Accelerometer ◽  
Linear Quadratic ◽  
Linear Quadratic Gaussian ◽  
Constant Altitude ◽  
The Military ◽  
Rotor Type

Micro air vehicles (MAVs) have a wide application such as the military reconnaissance, meteorological survey, environmental monitoring, and other aspects. In this paper, attitude and altitude control for Quad-Rotor type MAVs is discussed and analyzed. For the attitude control, a new method by using three gyroscopes and one triaxial accelerometer is proposed to estimate the attitude angle information. Then with the approximate linear model obtained by system identification, Model Reference Sliding Mode Control (MRSMC) technique is applied to enhance the robustness. In consideration of the relatively constant altitude model, a Linear Quadratic Gaussian (LQG) controller is adopted. The outdoor experimental results demonstrate the superior stability and robustness of the controllers.

scholarly journals On the Benefits of Semi-Active Suspensions with Inerters

2012 ◽  
Vol 19 (3) ◽  
pp. 257-272 ◽  
Author(s):  
Xin-Jie Zhang ◽  
Mehdi Ahmadian ◽  
Kong-Hui Guo
Keyword(s):  
High Performance ◽  
Control Method ◽  
Hybrid Control ◽  
Active Suspension ◽  
Vertical Acceleration ◽  
Active Suspensions ◽  
Quarter Car Model ◽  
Suspension Systems ◽  
Car Model ◽  
Quarter Car

Inerters have become a hot topic in recent years especially in vehicle, train, building suspension systems, etc. Eight different layouts of suspensions were analyzed with a quarter-car model in this paper. Dimensionless root mean square (RMS) responses of the sprung mass vertical acceleration, the suspension travel, and the tire deflection are derived which were used to evaluate the performance of the quarter-car model. The behaviour of semi-active suspensions with inerters using Groundhook, Skyhook, and Hybrid control has been evaluated and compared to the performance of passive suspensions with inerters. Sensitivity analysis was applied to the development of a high performance semi-active suspension with an inerter. Numerical simulations indicate that a semi-active suspension with an inerter has much better performance than the passive suspension with an inerter, especially with the Hybrid control method, which has the best compromise between comfort and road holding quality.

Linear quadratic Gaussian controller design for plasma current, position and shape control system in ITER

1999 ◽  
Vol 45 (1) ◽  
pp. 55-64 ◽  
Author(s):  
V Belyakov ◽  
A Kavin ◽  
V Kharitonov ◽  
B Misenov ◽  
Y Mitrishkin ◽  
...  
Keyword(s):  
Control System ◽  
Shape Control ◽  
Controller Design ◽  
Plasma Current ◽  
Current Position ◽  
Linear Quadratic ◽  
Linear Quadratic Gaussian
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