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A benchmark problem for robust feedback control of a manipulator is presented. The system to be controlled is an uncertain nonlinear two link ma-nipulator with elastic gear transmissions. The gear transmission is described by nonlinear friction and elasticity. The system is uncertain according to a parametric uncertainty description and due to uncertain(More)
Cover illustration: A well-known path used by robot customers and robot manufacturers for evaluating the path accuracy of industrial robots (front). One element of the multivariable frequency response function magnitude for a modern industrial robot (back). Linköping studies in science and technology. Dissertations. Abstract Industrial robot manipulators(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)
Swedish postgraduate education leads to a Doctor's degree and/or a Licentiate's degree. A Doctor's Degree comprises 240 ECTS credits (4 years of full-time studies). A Licentiate's degree comprises 120 ECTS credits, of which at least 60 ECTS credits constitute a Licentiate's thesis. Abstract Industrial robot manipulators are general-purpose machines used for(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)
This work investigates feedforward control of elastic robot structures. A general serial link elastic robot model which can describe a modern industrial robot in a realistic way is presented. The feedforward control problem is discussed and a solution method for the inverse dynamics problem is proposed. This method involves solving a differential algebraic(More)
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)
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. Abstract: A control(More)
High performance robot manipulators, in terms of cycle time and accuracy , require well designed control methods, based on accurate dynamic models. Robot manipulators are traditionally described by the flexible joint model or the flexible link model. These models only consider elasticity in the rotational direction. When these models are used for control or(More)