DEVELOPMENT OF THE BASe OF MODELS OF THE PARALLEL AND SEQUENCE STRUCTURE MANIPULATOR
The purpose of this work is to develop a method for synthesizing the base of models and controls (BMC) of program movements of a parallel-sequential structure manipulation system with a sequential three-stage controlled capture, taking into account the features of application in industrial processes and in the processing industry. The manipulator of the parallel-sequential structure, mounted on the rotary base, is investigated. A distinctive feature of the manipulator is the intersection of the geometric axes of the actuating links of the mechanism at the point of their attachment, which makes it possible to exclude the bending moment from external loads. The kinematic scheme of a manipulator constructed on the basis of a tripod and a gripping device with three degrees of freedom is given. The paper presents the movements of the manipulator's body during the execution of technological operations, and one of the movements of the working organ is considered to be vertical rectilinear motion (VM). To form the base of models and controls (BMC), a linguistic approximator is used to describe trajectories describing all possible technological movements of the mechanism in real time. A mathematical model of dynamics of manipulator movements of a parallel-sequential structure with seven degrees of freedom is developed. Dynamic analysis of the spatial mechanism of the manipulator is given. As a result of recording the kinetic energy of the manipulator, the component coefficients in the analytical form are determined. Analytic expressions of kinetic and potential energy of a manipulator with seven degrees of freedom are obtained. The proposed algorithm for deriving the dynamics equations for a manipulator of a parallel-sequential structure allows solving two main tasks, namely the determination of the driving forces and the moments necessary for the realization of the given program motions of the working member, and also the efforts in kinematic pairs. With known control efforts, the equations of dynamics make it possible to synthesize the necessary parameters of a control system with feedbacks that minimize dynamic errors in the development of program motions. On the basis of the received efforts in the executive links of the manipulator with rectilinear vertical movement of the gripping device, the laws of changing the manipulator's forces of a parallel-sequential structure with seven degrees of freedom are presented graphically.