Learning Control of Robot Manipulators

1993 ◽  
Vol 115 (2B) ◽  
pp. 402-411 ◽  
Author(s):  
Roberto Horowitz

Learning control encompasses a class of control algorithms for programmable machines such as robots which attain, through an iterative process, the motor dexterity that enables the machine to execute complex tasks. In this paper we discuss the use of function identification and adaptive control algorithms in learning controllers for robot manipulators. In particular, we discuss the similarities and differences between betterment learning schemes, repetitive controllers and adaptive learning schemes based on integral transforms. The stability and convergence properties of adaptive learning algorithms based on integral transforms are highlighted and experimental results illustrating some of these properties are presented.

Author(s):  
Lawrence Osa Adoghe

In this paper, an L-stable third derivative multistep method has been proposed for the solution of stiff systems of ordinary differential equations. The continuous hybrid method is derived using interpolation and collocation techniques of power series as the basis function for the approximate solution. The method consists of the main method and an additional method which are combined to form a block matrix and implemented simultaneously. The stability and convergence properties of the block were investigated and discussed. Numerical examples to show the efficiency and accuracy of the new method were presented.


2013 ◽  
Vol 2013 ◽  
pp. 1-15 ◽  
Author(s):  
Long Qin ◽  
Yabing Zha ◽  
Quanjun Yin ◽  
Yong Peng

Formation control of multirobot systems has drawn significant attention in the recent years. This paper presents a potential field control algorithm, navigating a swarm of robots into a predefined 2D shape while avoiding intermember collisions. The algorithm applies in both stationary and moving targets formation. We define the bounded artificial forces in the form of exponential functions, so that the behavior of the swarm drove by the forces can be adjusted via selecting proper control parameters. The theoretical analysis of the swarm behavior proves the stability and convergence properties of the algorithm. We further make certain modifications upon the forces to improve the robustness of the swarm behavior in the presence of realistic implementation considerations. The considerations include obstacle avoidance, local minima, and deformation of the shape. Finally, detailed simulation results validate the efficiency of the proposed algorithm, and the direction of possible futrue work is discussed in the conclusions.


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Eleonora Messina ◽  
Antonia Vecchio

We consider Volterra integral equations on time scales and present our study about the long time behavior of their solutions. We provide sufficient conditions for the stability and investigate the convergence properties when the kernel of the equations vanishes at infinity.


1990 ◽  
Vol 112 (4) ◽  
pp. 489-496 ◽  
Author(s):  
A. Hac´ ◽  
M. Tomizuka

This paper deals with discrete time learning controllers for systems with periodically varying parameters. Several control rules are proposed which use a basic principle of learning control that is to utilize the information from the most recent cycle to improve the system performance in the next cycle. Convergence properties of proposed learning control algorithms are examined. These algorithms can easily be implemented without additional measurements and without modification of existing feedback/feedforward controller. In a numerical example learning controllers are applied to eliminate the forced vibrations of a magnetically suspended rotor with nonsymmetric stiffness properties. The vibrations result from unbalanced inertia forces. Simulation results show that the learning controller is effective in absorbing periodic disturbances.


2009 ◽  
Vol 76 (2) ◽  
Author(s):  
E. H. van Brummelen

The subiteration method, which forms the basic iterative procedure for solving fluid-structure-interaction problems, is based on a partitioning of the fluid-structure system into a fluidic part and a structural part. In fluid-structure interaction, on short time scales the fluid appears as an added mass to the structural operator, and the stability and convergence properties of the subiteration process depend significantly on the ratio of this apparent added mass to the actual structural mass. In the present paper, we establish that the added-mass effects corresponding to compressible and incompressible flows are fundamentally different. For a model problem, we show that on increasingly small time intervals, the added mass of a compressible flow is proportional to the length of the time interval, whereas the added mass of an incompressible flow approaches a constant. We then consider the implications of this difference in proportionality for the stability and convergence properties of the subiteration process, and for the stability and accuracy of loosely coupled staggered time-integration methods.


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