Hybrid PD sliding mode control of a two degree-of-freedom parallel robotic manipulator

2013 ◽  
Author(s):  
J. M. Acob ◽  
V. Pano ◽  
P. R. Ouyang
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Robotic Manipulator ◽  
Degree Of Freedom ◽  
Mode Control ◽  
Two Degree Of Freedom

Sliding Mode Control for Two-Degree-Of-Freedom Fractional Zener Oscillator

2021 ◽  
Author(s):  
Jian Yuan ◽  
Song Gao ◽  
Liying Wang ◽  
Guozhong Xiu
Keyword(s):  
Sliding Mode Control ◽  
Fractional Order ◽  
Sliding Mode ◽  
Mechanical Energy ◽  
Equations Of Motion ◽  
Degree Of Freedom ◽  
Mode Control ◽  
Fractional Oscillator ◽  
Total Mechanical Energy ◽  
Two Degree Of Freedom

Abstract Fractional-order derivatives provide a powerful tool for the characterization of mechanical properties of viscoelastic materials. A fractional oscillator refers to mechanical model of viscoelastically damped structures, of which the viscoelastic damping is described by constitutive equations involving fractional-order derivatives. This paper proposes active control of vibration in a two-degree-of-freedom fractional Zener oscillator utilizing sliding mode technique. Firstly, with a state transformation, the fractional differential equations of motion are equivalently transformed into a relatively simple form. Meanwhile, a virtual fractional oscillator is generated, which is further used to analyze the original oscillator. Then, the stored energy in the two fractional derivative terms is derived based on the diffusive model of fractional integrator. Thus, the total mechanical energy in the virtual oscillator is determined as the sum of the kinetic energy, the potential energy and the fractional energy. Furthermore, sliding mode control of vibration in the fractional Zener oscillator is designed, of which the Lyapunov function is chosen as the total mechanical energy. Finally, numerical simulations are conducted to validate the effectiveness of the proposed controllers.

Improvement in the rollover stability of a liquid-carrying articulated vehicle via a new robust controller

2016 ◽  
Vol 231 (3) ◽  
pp. 322-346 ◽  
Author(s):  
Mohammad Amin Saeedi ◽  
Reza Kazemi ◽  
Shahram Azadi
Keyword(s):  
Control System ◽  
Sliding Mode Control ◽  
Dynamic Model ◽  
Sliding Mode ◽  
Degree Of Freedom ◽  
Roll Control ◽  
Mode Control ◽  
Active Steering ◽  
Articulated Vehicle ◽  
Active Roll Control

In this paper, in order to improve the roll stability of an articulated vehicle carrying a liquid, an active roll control system is utilized by employing two different control methods. First, a 16-degree-of-freedom non-linear dynamic model of an articulated vehicle is developed. Next, the dynamic interaction of the liquid cargo with the vehicle is investigated by integrating a quasi-dynamic liquid sloshing model with a tractor–semitrailer model. Initially, to improve the lateral dynamic stability of the vehicle, an active roll control system is developed using classical integral sliding-mode control. The active anti-roll bar is employed as an actuator to generate the roll moment. Next, in order to verify the classical sliding-mode control performance and to eliminate its chattering, the backstepping method and the sliding-mode control method are combined. Subsequently, backstepping sliding-mode control as a new robust control is implemented. Moreover, in order to prevent both yaw instability and jackknifing, an active steering control system is designed on the basis of a simplified three-degree-of-freedom dynamic model of an articulated vehicle carrying a liquid. In the introduced system, the yaw rate of the tractor, the lateral velocity of the tractor and the articulation angle are considered as the three state variables which are targeted in order to track their desired values. The simulation results show that the combined proposed roll control system is more successful in achieving target control and reducing the lateral load transfer ratio than is classical sliding-mode control. A more detailed investigation confirms that the designed active steering system improves both the lateral stability of the vehicle and its handling, in particular during a severe lane-change manoeuvre in which considerable instability occurs.

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