scholarly journals An approximate internal model-based neural control for serial robots with multiple clearance joints

2018 ◽  
Vol 10 (12) ◽  
pp. 168781401881232
Author(s):  
Lixin Yang ◽  
Xianmin Zhang

A dynamic model of serial robots with multiple clearance joints is developed. The contact phenomenon in the clearance joint is modeled by a continuous dissipative Hertz contact theory, and the friction force is calculated based on the modified Coulomb’s friction law. A neural network method is employed to predict the dynamic response, which avoids the problem in solving the differential algebraic equations. An approximate internal model-based neural control method is proposed to control the undesired effects arising from the joint clearances. The validity of the proposed method is verified by simulation results.

2017 ◽  
Vol 14 (1) ◽  
pp. 172988141668711
Author(s):  
Benyamine Allouche ◽  
Antoine Dequidt ◽  
Laurent Vermeiren ◽  
Michel Dambrine

Many works in the literature have studied the kinematical and dynamical issues of parallel robots. But it is still difficult to extend the vast control strategies to parallel mechanisms due to the complexity of the model-based control. This complexity is mainly caused by the presence of multiple closed kinematic chains, making the system naturally described by a set of differential–algebraic equations. The aim of this work is to control a two-degree-of-freedom parallel manipulator. A mechanical model based on differential–algebraic equations is given. The goal is to use the structural characteristics of the mechanical system to reduce the complexity of the nonlinear model. Therefore, a trajectory tracking control is achieved using the Takagi-Sugeno fuzzy model derived from the differential–algebraic equation forms and its linear matrix inequality constraints formulation. Simulation results show that the proposed approach based on differential–algebraic equations and Takagi-Sugeno fuzzy modeling leads to a better robustness against the structural uncertainties.


Aerospace ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 9 ◽  
Author(s):  
David Quero ◽  
Pierre Vuillemin ◽  
Charles Poussot-Vassal

In this work, a new approach for the generation of a generalized state-space aeroservoelastic model based on tangential interpolation is presented. The resulting system of differential algebraic equations (DAE) is reduced to a set of ordinary differential equations (ODE) by residualization of the non-proper part of the transfer function matrix. The generalized state-space is of minimal order and allows for the application of the force summation method (FSM) for the aircraft loads recovery. Compared to the classical rational function approximation (RFA) approach, the presented method provides a minimal order realization with exact interpolation of the unsteady aerodynamic forces in tangential directions, avoiding any selection of poles (lag states). The new approach is applied first for the generation of an aerodynamic model for the bidimensional unsteady incompressible flow in the time domain. Next, an application on the generation of an aeroservoelastic model for loads evaluation of the flutter reduced order assessment (FERMAT) model under atmospheric disturbances is done, showing an excellent agreement with the reference model in the frequency domain. The proposed aeroservoelastic model of minimal order is suited for loads analysis and multivariable control design, and an application to a gust loads alleviation (GLA) strategy is shown.


2013 ◽  
Vol 385-386 ◽  
pp. 872-876 ◽  
Author(s):  
Wen Lei Li ◽  
Wei Xing Lin

For the single machine connected to infinite bus power system with uncertainties, one nonlinear coordinated control scheme for Static Synchronous Compensator (STATCOM) and excitation is proposed in this paper. Firstly, in order to avoid solving the differential algebraic equations (DAEs) model of system, we simplify the DAEs into the classical differential equations, and then a new nonlinear parameter strict feedback model is given. Secondly, in order to make the system achieve the desired results, the controller is designed in two parts based on improved dynamic surface control method (IDSC) and passive control techniques. The theoretical analysis shows that the derived controller can not only attenuate the influences of external disturbances, but also has strong robustness for system parameters variety. The control law obtained is more effective and the system globally and uniformly ultimately bounded can be achieved using full nature of nonlinear dynamic. Lastly, the further simulation results indicate that the proposed controller can ensure transient stability of the power system under large sudden fault.


2016 ◽  
Author(s):  
Matthias Johannink

This thesis is concerned with the integration of a model-based and experimental analysis for the systematic investigation of transient electrodialysis (ED) processes. In this context a mechanistic process model for transient ED systems is developed which is based on a rigorous dynamic description of the underlying ionic transport processes. Important requirements for a systematic model development are elaborated in a systematic manner. This includes the development of a new method for the characterization of partial differential-algebraic equations and an experimental sensitivity analysis of a transient electrodialysis system. The findings can easily be generalized to related electrochemical processes such as fuel cells or batteries. By this means this work provides important results for scientist and engineers in the fields of mechanistic modeling, electromembrane processes and electrochemical systems. ...


Author(s):  
Ambrus Zelei ◽  
La´szlo´ L. Kova´cs ◽  
Ga´bor Ste´pa´n

The paper presents the dynamic analysis of a crane-like manipulator system equipped with complementary cables and ducted fan actuators. The investigated under-actuated mechanical system is described by a system of differential-algebraic equations. The position/orientation control problem is investigated with respect to the trajectory generation and the fine positioning of the payload. The closed form results include the desired actuator forces as well as the nominal load angle corresponding to the desired motion of the payload. Considering a PD controller, numerical simulation results and also experiments demonstrate the applicability of the concept of using complementary actuators for controlling the swinging motion of the payload.


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