Bending and Torsional Vibration Control of a Flexible Structure Using H-infinity Based Approach

1997 ◽  
Vol 9 (5) ◽  
pp. 387-392
Author(s):  
Indra N. Kar ◽  
◽  
Kazuto Seto
Keyword(s):  
Torsional Vibration ◽  
Controller Design ◽  
Design Method ◽  
Flexible Structure ◽  
Mass Model ◽  
H Infinity ◽  
Actuator Dynamics ◽  
Lumped Parameter ◽  
Dynamic Output Feedback Controller ◽  
Three Degree Of Freedom

This paper presents a method of controlling the bending and torsional vibration mode of a flexible structure using H-infinity optimal control. A new idea is proposed in order to reduce the unmodeled system uncertainties by placing actuators in the nodes of certain neglected vibration modes. Then, the controller is designed based on the reduced order model and is capable of attenuating vibration without causing spillover instability. For this purpose, a three degree of freedom lumped parameter mass model of a plate structure is considered to control its vibrations using a dynamic output feedback controller. The actuator dynamics and the placement of the actuators are considered for a effective controller design method. The efficacy of the controller is shown through simulations.

Robust Vibration/Force Control of a 2 D.O.F. Arm Having One Flexible Link with Artificial Pneumatic Actuators

2002 ◽  
Vol 8 (3) ◽  
pp. 405-423 ◽  
Author(s):  
No-Cheol Park ◽  
Hyung-Wug Park ◽  
Hyun Seok Yang ◽  
Young-Pil Park
Keyword(s):  
Force Control ◽  
Controller Design ◽  
Design Method ◽  
Strong Nonlinearity ◽  
Flexible Link ◽  
Muscle Type ◽  
Singular Perturbation Method ◽  
Actuator Dynamics ◽  
Pneumatic Muscle ◽  
Artificial Pneumatic Muscle

A flexible link of a manipulator has an advantage over a rigid link in the sense that, not only is it light-weighted and thus can move fast using a small-sized actuator, but also that it is safer when it comes into contact with its environment, in particular with humans. However, the vibration due to the flexibility of the link makes it difficult to control the position of the end-point with precision, and when the link is in contact with its environment the problem becomes further complicated. On the other hand, if an actuator can deliver enough force while maintaining proper compliance, it would be advantageous for the sake of safety. An artificial pneumatic muscle-type actuator is an adequate choice in this case. However, the dynamic characteristics of this particular actuator possess strong nonlinearity and load-dependency, and thus a number of problems need to be resolved for its successful application as an actuator. In this work, the position and force control problem of a two-d.o.f. arm system having a flexible second link with artificial pneumatic muscle-type actuators is addressed. A composite controller design method is proposed in the framework of the singular perturbation method. Various robust control schemes are designed in order to meet with payload variation, parameter uncertainty, unmodelled vibration mode and actuator dynamics, both in the slow and the fast subsystems. Simulations and experimental results confirm the effectiveness of the suggested composite control scheme.

Robust Control of Formation Dynamics for Autonomous Underwater Vehicles in Horizontal Plane

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Huizhen Yang ◽  
Fumin Zhang
Keyword(s):  
Formation Control ◽  
Controller Design ◽  
Autonomous Underwater Vehicles ◽  
Underwater Vehicles ◽  
Loop Formation ◽  
Robust Controller ◽  
H Infinity ◽  
Three Degree Of Freedom ◽  
Jacobi Transform ◽  
Robust Controller Design

This paper presents a novel robust controller design for formation control of autonomous underwater vehicles (AUVs). We consider a nonlinear three-degree-of-freedom dynamic model for the horizontal motion of each AUV. By using the Jacobi transform, the horizontal dynamics of AUVs are explicitly expressed as dynamics for formation shape and formation center, and are further decoupled by feedback control. We treat the coupling terms as perturbations to the decoupled system. An H-infinity state feedback controller is designed to achieve robust stability of the closed loop formation and translation dynamics. By incorporating an orientation controller, the formation shape under control converges and the formation center tracks a desired trajectory simultaneously. Simulation results demonstrate the effectiveness of the controllers.

scholarly journals H-infinity Sliding Mode Controller Design for a Human Swing Leg System

2020 ◽  
Vol 23 (2) ◽  
pp. 117-126
Author(s):  
Hazem I. Ali ◽  
Azhar Jabbar Abdulridha
Keyword(s):  
Knee Joint ◽  
Hip Joint ◽  
Controller Design ◽  
Sliding Mode ◽  
Knee Joints ◽  
Upper Body ◽  
Double Pendulum ◽  
H Infinity ◽  
Dynamic Output Feedback Controller ◽  
Better Than

In this paper, the H-infinity Sliding Mode Control (HSMC) is designed to produce a new dynamic output feedback controller for trajectory tracking of the nonlinear human swing leg system. The human swing leg system represents the support of human leg or the humanoid robot leg which is usually modeled as a double pendulum. The thigh and shank of a human leg is represented by two pendulum links and the hip joint will connect the upper body to the thigh and the knee joint will connect the thigh to the shank. The external torques (servo motors) are applied at the hip and knee joints to move the muscles of thigh and shank. The results show that the HSMC can robustly stabilize the system and achieve a desirable time response specification better than if only H-infinity or SMC is used. This controller achieves the following specifications:  sec,  for hip joint and sec, for knee joint.

H-infinity controller design for chatter suppression in machining based on integrated cutting and flexible structure model

Automatica ◽  
2021 ◽  
pp. 109643
Author(s):  
Prapon Ruttanatri ◽  
Matthew O.T. Cole ◽  
Radom Pongvuthithum ◽  
Satiengpong Huyanan
Keyword(s):  
Controller Design ◽  
Flexible Structure ◽  
Structure Model ◽  
H Infinity ◽  
Chatter Suppression
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