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Virtual Actuator with Integral Part

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Nowadays technological systems are designed to meet the growing demands for safety and performance. This is emphasized especially for safety-critical applications such as aviation, aerospace or nuclear systems. Even small unnoticed and seemingly insignificant error or incorrect reaction to the error ca lead to catastrophic failure of the entire system. New control techniques and design approaches are developed to avoid fatal failures. These novel techniques and approaches are also able to adjust the required levels of performance including stability of the overall system in addition to ability to handle faults of the system. Such control systems are called fault tolerant control systems. Ability to achieving a certain level of system performance during occurence of fault in system components is sign of a degree of redundancy in the system. However reaching the level of performance may be limited by physical or economical means. Effective solution to this situation is to reduce the performance demands on system. Sometimes requirements have to be reduced to the stabilization only of the most important parts of the system. During occurence of the fault of one actuator the entire system and its performance depends on rest of actuators and their performance li, etc. and its performance depends on component limits. Therefore it is important to avoid excessive load of actuators and thus the risk of failure of the system. Often the remaining actuators are used to achieve state of the system that is considered to by safe instead to continue the task. The paper presents three different methods for control reconfiguration using virtual actuators that stabilize the system with the faulty actuator. Control algorithms as well as the conditi... ... middle of paper ... ...ther actuator is added in following simulations to replace actuator during failure so number of outputs of the system is equal to number of inputs. Extended nominal system and extended system with fault is used similarly as in previous part. In case of failure of the first actuator all state space variables are stabilized at desired values without permanent control deviation after start of the virtual actuator in time 70 seconds. Respons of the system can be seen on the following figure. Further simulations of virtual actuator with integral part are performed with extended system during failure of the third and fourth actuator. Goal of weak reconfiguration is accomplished simillarly as in previous part. Controlled variables achieve desired values hovever uncotrolled variables stabilize at non-zero values. Simulation results are summarized in following table.
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