In this paper, we study the problem of estimating unknown parameters in nonlinear gray-box models that may be multivariable, nonlinear, unstable, and resonant at the same time. A straightforward use of time-domain predication-error methods for this type of problem easily ends up in a large and numerically stiff optimization problem. We therefore propose an… (More)
— This paper investigates methods for tool position estimation of industrial robots. It is assumed that the motor angular position and the tool acceleration are measured. The considered observers are different versions of the extended Kalman filter as well as a deterministic observer. A method for tuning the observers is suggested and the robustness of the… (More)
Estimates from an extended Kalman filter (EKF) is used in an Iterative Learning Control (ILC) algorithm applied to a realistic two-link robot model with flexible joints. The angles seen from the arm side of the joints (arm angles) are estimated by an EKF in two ways: 1) using measurements of angles seen from the motor side of the joints (motor angles),… (More)
A benchmark problem for robust feedback control of a flexible manipula-tor is presented together with some suggested solutions. The system to be controlled is a four-mass system subject to input saturation, nonlinear gear elasticity, model uncertainties and load disturbances affecting both the motor and the arm. The system should be controlled by a… (More)
A control engineering benchmark problem with industrial relevance is presented. The process is a simulation model of a nonlinear four-mass system, which should be controlled by a discrete-time controller that optimizes performance for given robustness requirements. The control problem concerns only the so-called regulator problem.
The 3[superscript rd] generation of robotics : ubiquitous robot p. 2 Robot navigation using biosonar for natural landmark tracking p. 3 Design of a semiautonomous biomimetic underwater vehicle for environmental monitoring p. 9 The null-space-based behavioral control for mobile robots p. 15 Experimental comparison of a directed and a non-directed potential… (More)