PARAMETRIC FAILURES AND RATIONAL ALLOCATION RELIABILITY OF ROBOT MACHINE SUBSYSTEMS

Abstract

The article deals with the issues of parametric failures of the mechanisms of the parallel structure of robotic machines. The variety of functions performed by robots has led to the creation of machine tools with mechanisms of a parallel structure. The basis for creating a line of robotic machines with three telescopic rods is the structure of a tripod with a vertical stand of constant length, hinged to the bed and the center of the movable platform. The central passive kinematic chain blocks the scrolling of the movable platform with the executive body around its own axis, perceives workloads and gives the mechanism a kinematic certainty. For modern technical means, consisting of many interacting mechanisms, apparatuses and devices, the failure of at least one critical element of a complex system without redundancy can lead to disruption of the entire system. According to the operation of typical designs of tripod-type robots, the distribution of element failures was established and it was found that the “weak elements” are hydraulic drive seals that cause leakage. Insufficient equipment reliability leads to huge repair costs, equipment downtime, failure to perform critical tasks, sometimes to accidents associated with large economic losses, destruction of large facilities and human casualties. At the stage of industrial production of technological equipment, the reliability of robotic machines is of paramount importance. To optimize the level of reliability of the tricep subsystem, a method of rational distribution of the reliability of elements is proposed. The modeling of the phenomena of kinematic locking of the parallel structure mechanism is carried out and the corresponding criterion of parametric failures is proposed. For a robot-machine with mechanisms of a parallel structure, which has three parallel mechanisms for the translational movement of rods, three subsystems are identified and a method for rational distribution of reliability between such subsystems is proposed. An algorithm for the structural synthesis of the reliability of mechanisms of a parallel structure of the tricep type has been developed and practical recommendations have been developed for the optimal distribution of reliability standards between the subsystems of a robot-machine at the design stage.