Position Control of Pneumatic System Using High Gain and Backstepping Controllers

Author(s):  
S. Hajji ◽  
A. Ayadi ◽  
M. Smaoui ◽  
T. Maatoug ◽  
M. Farza ◽  
...  

This paper investigates the applicability of two state feedback controllers for a class of uniformly controllable and observable nonlinear systems. The first one is based on an appropriate high gain control principle that has been developed by duality from the high gain observer principle. The state feedback control gain is particularly provided by a synthesis function satisfying a well-defined condition, leading thereby to a unification of the high gain control designs. The second one is a backstepping controller that has been developed from a suitable combination of the backstepping control approach bearing in mind the high gain control principle pursued for the first controller design. A common engineering design feature that is worth to be mentioned consists in properly formulating their underlying control problems as a regulation problem involving a suitable reference model with respect to the structure of the system as well as the control design principle under consideration. Of fundamental interest, the involved reference model is systematically derived thanks to the flatness and backstepping principles using an appropriate Lyapunov approach. An experimental evaluation is carried out to illustrate the efficiency of the proposed nonlinear controllers.

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Xiaojun Wang ◽  
Jiankun Sun ◽  
Guipu Li

This paper investigates the finite-time position tracking control problem of pneumatic servo systems subject to hard nonlinearities and various disturbances. A finite-time disturbance observer is firstly designed, which guarantees that the disturbances can be accurately estimated in a finite time. Then, by combining disturbances compensation and state feedback controller together, a nonsmooth composite controller is developed based on sliding mode control approach and homogeneous theory. It is proved that the tracking errors under the proposed composite control approach can be stabilized to zero in finite time. Moreover, compared with pure state feedback control, the proposed composite control scheme offers a faster convergence rate and a better disturbance rejection property. Finally, numerical simulations illustrate the effectiveness of the proposed control scheme.


2008 ◽  
Vol 31 (1) ◽  
pp. 115-125 ◽  
Author(s):  
Achim Ilchmann ◽  
Eugene P. Ryan

Author(s):  
Hao Chen ◽  
Zhenzhen Zhang ◽  
Huazhang Wang

This paper investigates the problem of robust H ∞ control for linear systems. First, the state-feedback closed-loop control algorithm is designed. Second, by employing the geometric progression theory, a modified augmented Lyapunov–Krasovskii functional (LKF) with the geometric integral interval is established. Then, parameter uncertainties and the derivative of the delay are flexibly described by introducing the convex combination skill. This technique can eliminate the unnecessary enlargement of the LKF derivative estimation, which gives less conservatism. In addition, the designed controller can ensure that the linear systems are globally asymptotically stable with a guaranteed H ∞ performance in the presence of a disturbance input and parameter uncertainties. A liquid monopropellant rocket motor with a pressure feeding system is evaluated in a simulation example. It shows that this proposed state-feedback control approach achieves the expected results for linear systems in the sense of the prescribed H ∞ performance.


Actuators ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 1 ◽  
Author(s):  
Johannes T. Stoll ◽  
Kevin Schanz ◽  
Andreas Pott

Robots that enable safe human-robot collaboration can be realized by using compliant drive units. In previous works, different mechanical designs of compliant pneumatic rotary drive units with similar characteristics have been presented. In this paper, we present the overall control approach that we use to operate one of these compliant pneumatic rotary drive units. We explain the mechanical design and derive the differential equation that describes the dynamics of the system. In order to successfully operate a pneumatic drive unit with three or more working chambers, the torque specified by the controller has to be split up onto the working chambers. We transfer the well-known field-oriented control approach from electric motors to the investigated pneumatic drive unit to create such a torque mapping. Moreover, we develop optimized torque mappings that are tailored to work with this type of drive unit. Furthermore, we introduce and compare two control algorithms based on different implementations of state feedback to realize position control. Finally, we present the step responses that we achieve when we implement either one of the control algorithms in combination with the different torque mappings.


1996 ◽  
Vol 118 (1) ◽  
pp. 113-119 ◽  
Author(s):  
C.-H. Chuang ◽  
D.-N. Wu ◽  
Q. Wang

In order to prevent structural damages, it is more important to bound the vibration amplitude than to reduce the vibration energy. However, in the performance index for linear quadratic regulator (LQR), the instantaneous amplitude of vibration is not minimized. An ordinary LQR may have an unacceptable amplitude at some time instant but still have a good performance. In this paper, we have developed an LQR with adjustable gains to guarantee bounds on the vibration amplitude. For scalar systems, the weighting for control is switched between two values which give a low-gain control when the amplitude is inside the bound and a high-gain control when the amplitude is going to violate the given bound. For multivariable systems, by assuming a matching condition, a similar controller structure has been obtained. This controller is favored for application since the main structure of a common LQR is not changed; the additional high-gain control is required only if the vibration amplitude fails to stay inside the bound. We have applied this controller to a five-story building with active tendon controllers. The results show that the largest oscillation at the first story stays within a given bound when the building is subject to earthquake excitation.


Author(s):  
Karthik Chandran ◽  
Weidong Zhang ◽  
Rajalakshmi Murugesan ◽  
S. Prasanna ◽  
A. Baseera ◽  
...  

Decentralized Model Reference Adaptive Control problems are investigated for a class of linear time-invariant two time-scale model, having fast and slow dynamics and unmatched interconnections. Design of full state feedback controller is a critical task to the system having interrelated dynamics and nonlinear interconnections of time varying lags, however, can be addressed by singular perturbation procedures and time scale modeling. In this research, full order observer-based state feedback control is designed to two-time scale system to ensure the stability of the closed loop system. Then, decentralized model reference adaptive controller with the novel reference model is designed to individual subsystems. It is found that the proposed design enforces the system states to track the reference state asymptotically. To investigate the proposed design, an example of drying process is considered. Simulation results are analyzed to confirm the efficacy of the proposed control scheme.


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