Мехатроника 1 Бөлім mechatronics
5.6 Reliability of complex systems
жүктеу/скачать 11,25 Mb. Pdf көрінісі
|
Мехатроника 1 том Баймухамедов М.Ф., Джаманбалин Қ.Қ.,Ақгул м.К.
| 248
5.6 Reliability of complex systems The mechatronic module is a complex system consisting of many different elements, interconnected in various ways. Therefore, the reliability calculation of the MM is carried out taking into account the reliability of its constituent elements and the scheme of their connection. When the independent elements are connected in series (Fig. 5.2), the failure of one element results in the failure of the entire system. Figure 5.2 The probability of failure-free operation of the system with a successive combination of elements is equal to the product of the probabilities of failure- free operation of its individual elements: Where P i (x) is the probability of the absence of sudden failures; If Then Usually the probability of failure-free operation of the elements is quite high. Therefore, expressing P i (t) = 1 – Q i (t) and substituting in the formula (17.1), after transformations and discarding products of small quantities, we get: When Will have: Reliability of complex systems with serial connection of elements is low. For example, with the number of elements of the system n = 10 with the probability 249 of failure-free operation of each element P(t) = 0.9 (as in rolling bearings), the overall probability of failure-free operation of the system is: When the independent elements are connected in parallel (Figure 5.3), the failure of the system occurs when all elements that are switched on in parallel fail. Figure 5.3 In this case, the probability of failure-free operation is equal [25,26]: If Then With the same data as in the example for serial connection of the elements, the probability of failure-free operation with parallel connection of the elements is: |