Robust Control of Generalized Dynamic Systems Without the Matching Conditions

1991 ◽  
Vol 113 (4) ◽  
pp. 582-589 ◽  
Author(s):  
Zhihua Qu ◽  
John Dorsey

A general control law and a set of conditions are proposed to guarantee the stability of dynamic systems with bounded uncertainties. The results do not require the matching conditions on the uncertainties and subsume several existing results as special cases. Moreover, it is shown that there is at least one class of uncertain dynamic systems which can always be stabilized under the proposed control law no matter what the size and the structure of the input-unrelated uncertainties.

1988 ◽  
Vol 55 (4) ◽  
pp. 992-994 ◽  
Author(s):  
Y. H. Chen ◽  
Chieh Hsu

The stability property for a class of dynamic systems with uncertain parameter variation is studied. The uncertainty can be fast time-varying and unpredictable. A new approach for stability study is proposed. The only required information on the uncertain variation is its possible bound as well as structure. That is, no a priori knowledge on the realization of the variation is needed.


2021 ◽  
Vol 54 (4) ◽  
pp. 641-647
Author(s):  
Mukul Kumar Gupta ◽  
Roushan Kumar ◽  
Varnita Verma ◽  
Abhinav Sharma

In this paper the stability and tracking control for robot manipulator subjected to known parameters is proposed using robust control technique. The modelling of robot manipulator is obtained using Euler- Lagrange technique. Three link manipulators have been taken for the study of robust control techniques. Lyapunov based approach is used for stability analysis of triple link robot manipulator. The Ultimate upper bound parameter (UUBP) is estimated by the worst-case uncertainties subject to bounded conditions. The proposed robust control is also compared with computer torque control to show the superiority of the proposed control law.


1995 ◽  
Vol 1 (1) ◽  
pp. 1-10 ◽  
Author(s):  
V. Lakshmikantham ◽  
Z. Drici

A basic feedback control problem is that of obtaining some desired stability property from a system which contains uncertainties due to unknown inputs into the system. Despite such imperfect knowledge in the selected mathematical model, we often seek to devise controllers that will steer the system in a certain required fashion. Various classes of controllers whose design is based on the method of Lyapunov are known for both discrete [4], [10], [15], and continuous [3–9], [11] models described by difference and differential equations, respectively. Recently, a theory for what is known as dynamic systems on time scales has been built which incorporates both continuous and discrete times, namely, time as an arbitrary closed sets of reals, and allows us to handle both systems simultaneously [1], [2], [12], [13]. This theory permits one to get some insight into and better understanding of the subtle differences between discrete and continuous systems. We shall, in this paper, utilize the framework of the theory of dynamic systems on time scales to investigate the stability properties of conditionally invariant sets which are then applied to discuss controlled systems with uncertain elements. For the notion of conditionally invariant set and its stability properties, see [14]. Our results offer a new approach to the problem in question.


Author(s):  
Saeid Khosravani ◽  
Iman Fadakar ◽  
Amir Khajepour ◽  
Baris Fidan ◽  
Bakhtiar Litkouhi ◽  
...  

Guaranteeing stability of a vehicle without considering the driver in the control loop is difficult. In this paper, a driver-in-the-loop control strategy is proposed to improve the lateral vehicle behavior and extend the stability margin. The driver is modeled as a delayed linear controller with the aim of tracking the desired path. The main aim of the controller design is to track the desired yaw rate of the vehicle considering the driver effects. To make an implementable approach, it is assumed that the desired road information and the exact values of longitudinal and lateral forces are not available for the control level and the controller treats them as bounded uncertainties. The nonlinear damping technique is adopted to stabilize the yaw rate error. For two different robust designs, we have shown that the yaw rate error will confine inside a certain neighborhood even in the presence of uncertainty. The size of this neighborhood is directly proportionate to the gain of the robust control terms and the driver characteristics. A standard harsh double lane change scenario is simulated as the desired path for the driver. The results demonstrate that the design process improves the overall behavior of the driver-vehicle system in the presence of bounded uncertainties.


2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Juan Ignacio Mulero-Martínez

The problem of stabilization of uncertain systems plays a broad and fundamental role in robust control theory. The paper examines a boundedness theorem for a class of uncertain systems characterized as having a decreasing Lyapunov function in a ringlike region. It is a systematic study on stability that embraces both the transient and steady analysis, covering such aspects as the maximum overshoot of the system state, the stability region and the exponential convergence rate. The emphasis throughout is on deriving dominant time constants and explicit time expressions for a state to reach an invariant set. The central theorem provides a complete treatment of the time evolution of trajectories depending on the specific compact set of initial conditions. Toward this end, the comparison lemma along with a particular Riccati differential equation are essential and conclusive. The scope of questions addressed in the paper, the uniformity of their treatment, the novelty of the proposed theorem, and the obtained results make it very useful with respect to other works on the problem of robust nonlinear control.


Sign in / Sign up

Export Citation Format

Share Document