On heat dissipation control of linear variable reluctance motors

Abstract only

Fast visual tracking and localization in multi-agent systems

In this paper an implementation of an algorithm for fast visual tracking and localization of mobile agents has been described. Based on an extremely rapid method for visual detection of an object, described localization strategy provides a real time solution suitable for the design of multi-agent control schemes. The agents tracking and localization is carried out through five differently trained cascades of classifiers that process images captured by cameras mounted on agents. In this way, each agent is able to determine relative positions and orientations of all other agents performing tasks in its field of view. The described localization method is suitable for applications involving robot formations. Performance of the proposed method has been demonstrated on a laboratory setup composed of two mobile robot platforms

Fast visual tracking and localization in multi-agent systems

In this paper an implementation of an algorithm for fast visual tracking and localization of mobile agents has been described. Based on an extremely rapid method for visual detection of an object, described localization strategy provides a real time solution suitable for the design of multi-agent control schemes. The agents tracking and localization is carried out through five differently trained cascades of classifiers that process images captured by cameras mounted on agents. In this way, each agent is able to determine relative positions and orientations of all other agents performing tasks in its field of view. The described localization method is suitable for applications involving robot formations. Performance of the proposed method has been demonstrated on a laboratory setup composed of two mobile robot platforms

Smooth adaptive compensation of the input hysteresis

Abstract onl

Smooth parametric hysteresis operator for control

Hysteresis is a non-linear phenomenon present in many physical systems that is usually undesirable and degrades their performance. Models which accurately reproduce hysteresis are often very complex and hard to implement. For that reason, the hysteresis is generally, when the performance specifications are not too strict, treated as a bounded disturbance or is approximated with piecewise affine structures. Control design requires models which extract the most fundamental behavior of phenomena and, in this article, such a model was constructed for the hysteresis phenomenon. It is shown that the obtained model can be easily shaped, mathematically manipulated and used for general control design of hysteretic systems, e.g. feed-forward compensation

On hysteresis and air gap disturbance in current and voltage mode feed-forward control of variable reluctance actuators

Current and voltage mode control approaches in feed-forward force control of variable reluctance actuators are analyzed and compared. Two major error generators, the unknown air gap variation and hysteresis, are investigated together with the quantification of their influence on the final force tracking error, and it is shown that voltage control has fundamental advantages over current control. Furthermore, linearization laws with hysteresis compensation based on the parametric hysteresis operator are proposed and compared on a high-fidelity actuator model which is derived from the behavior of magnetic materials, the actuator structure, and first principle physical models

Linearization of a current-driven reluctance actuator with hysteresis compensation

This paper investigates the influence of hysteresis present in the ferromagnetic core of a variable reluctance actuators on the force reproducibility. To reduce this influence and to boost reproducibility, a hysteretic inverse actuator model is derived and used to linearize a current-driven reluctance actuator. Furthermore, an identification procedure for identifying the parameters of the hysteresis model and the remaining actuator non-linearities is presented. Two actuators are experimentally tested with the proposed compensator and a linearization error smaller than 0.05% of the maximum force is achieved, which is an order of magnitude improvement over single-valued inverse compensators. A comparably small error is obtained for non-trivial, non-periodic inputs when higher order reversal curves of the actuator hysteresis have to be reproduced as well. The simple structure of the compensator allows a fast implementation in digital controllers

Linearization of a current-driven reluctance actuator with hysteresis compensation

This paper investigates the influence of hysteresis present in the ferromagnetic core of a variable reluctance actuators on the force reproducibility. To reduce this influence and to boost reproducibility, a hysteretic inverse actuator model is derived and used to linearize a current-driven reluctance actuator. Furthermore, an identification procedure for identifying the parameters of the hysteresis model and the remaining actuator non-linearities is presented. Two actuators are experimentally tested with the proposed compensator and a linearization error smaller than 0.05% of the maximum force is achieved, which is an order of magnitude improvement over single-valued inverse compensators. A comparably small error is obtained for non-trivial, non-periodic inputs when higher order reversal curves of the actuator hysteresis have to be reproduced as well. The simple structure of the compensator allows a fast implementation in digital controllers

High-precision force control of short-stroke reluctance actuators with an air gap observer

\u3cp\u3eA short-stroke reluctance actuator linearization scheme that simultaneously achieves high linearity, high bandwidth, and low stiffness is demonstrated. These properties are required in high speed and high precision motion systems. They are achieved by combining various control schemes, namely flux feedforward and analog sensing coil feedback for high bandwidth, Hall probe feedback to stabilize the drift, and an air gap observer together with gain scheduling to reduce the remaining stiffness. Using the presented scheme, the attractive force of the actuator can be controlled with high precision without the need for a position or force sensor. Experiments indicate that a linearization error of 50mN for second-order 200 N force reference profiles is obtained. This translates into force predictability of 99.98%. Furthermore, absolute actuator stiffness below 500 N/m at force levels of 100 N is achieved, which is comparable to more linear Lorentz actuators.\u3c/p\u3