Position control of a manipulator with one flexible link

2007 ◽  
Author(s):  
Jorge M. Martins ◽  
Alexandre N. Paris ◽  
Jose M. G. Sa da Costa
Keyword(s):  
Position Control ◽  
Flexible Link

Robust Control of Three-Dimensional Compliant Mechanisms

2016 ◽  
Vol 138 (10) ◽  
Author(s):  
Erfan Shojaei Barjuei ◽  
Paolo Boscariol ◽  
Renato Vidoni ◽  
Alessandro Gasparetto
Keyword(s):  
Control Systems ◽  
Position Control ◽  
Compliant Mechanisms ◽  
Mass Density ◽  
Three Dimensional ◽  
Vibration Damping ◽  
Flexible Link ◽  
External Disturbances ◽  
Uncertainty Model ◽  
Open Issues

Position control and vibration damping of flexible-link mechanisms are still challenging open issues in robotics. Finding solutions for these problems can lead to improvement in the operation and accuracy of the manipulators. In this paper, the synthesis of robust controllers based on H∞ loop shaping and μ-synthesis for both position control and vibration damping in a spatial flexible L-shape mechanism with gravity is presented. The design of the controllers is based on the evaluation of an uncertainty model which takes into account a ±20% uncertainty in the elasticity and mass density of the links. The response of each controller is tested also in the presence of external disturbances with the aid of highly accurate numerical simulations; furthermore, a comparison between the robust performances of synthesized controllers is presented in order to show the effectiveness of synthesized control systems.

Angular Positioning and Vibration Control of a Slewing Flexible Control by Applying Smart Materials and Sliding Modes Control

2017 ◽  
Author(s):  
Frederic C. Janzen ◽  
Jose M. Balthazar ◽  
Angelo M. Tusset ◽  
Rodrigo T. Rocha ◽  
Jeferson Jose de Lima
Keyword(s):  
Vibration Control ◽  
Smart Materials ◽  
Position Control ◽  
Control Method ◽  
Angular Position ◽  
Dc Motor ◽  
Sliding Modes ◽  
Flexible Link ◽  
Positioning Control ◽  
Sma Actuators

Flexible links undergoing a slewing motion are widely found in aerospace structures such as satellites and robotic manipulators. In this kind of systems, the lighter the structure the better is its performance and more cost effective is the system. However, the positioning control of flexible structures is challenging because the flexibility may lead the system to vibrate in larger amplitudes, which makes the need of using actuators to control and reduce vibrations. An alternative for those actuators is the use of smart materials, as SMA (Shape Memory Alloys) to control vibrations of such structures. This work will present the angular positioning and vibration control of a flexible link. The angular position control is a torque driven by a DC motor controlled through a sliding modes control method. The system is considered as non-ideal, it means that the vibration of the flexible link accomplishes to the DC motor shaft. SMA actuators are coupled to the flexible link with the objective to reduce the vibration amplitudes and reducing so the settling time of the system. The SMA actuators are controlled through an electric voltage applied to its terminals by applying the Sliding modes control method. The dynamical equations of motion for the system are developed considering a dead zone nonlinearity of the DC motor and a phenomenological model for the SMA. The flexible link is modeled as a continuous structure and just the first vibration mode is analyzed. Numerical simulations results are presented to demonstrate the effectiveness of the sliding modes strategy for the positioning control of the DC motor and for the vibration suppression of the flexible link by using SMA actuators.

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