ЧИСЛЕННЫЙ АНАЛИЗ КИНЕМАТИКИ И ДИНАМИКИ РЕКОНФИГУРИРУЕМОГО МАНИПУЛЯТОРА С МНОГОРЕЖИМНЫМ ПОСТУПАТЕЛЬНЫМ ДВИЖЕНИЕМ ВЫХОДНОГО ЗВЕНА

МАШИНОВЕДЕНИЕ

Abstract

Most of the known parallel manipulators are based on the architecture of the GoughStewart platform due to its inherent advantages. Among them, the manipulators with a limited number of degrees of freedom deserve special attention, since they retain all the advantages of parallel mechanisms, but require a minimum number of actuators and moving masses. The paper is devoted to the study of kinematics and dynamics of a reconfigurable parallel manipulator with 3 degrees of freedom ensuring a spatial translatory motion of the output link. The manipulator consists of a frame and a movable platform connected by three identical RRCtype sub-chains. The drives controlling the degrees of freedom of the manipulator are installed on its three pivots and can be operated by DC motors. All the links of the sub-chains have the same length, while the axes of rotational and cylindrical pairs of each sub-chain are parallel to one of the coordinate axes. These geometric conditions make it possible to decompose the three rectilinear translational movements of the platform along the coordinate axes and implement any of them by two sub-chains with the fixed pivot of the third, since together they form the well known Sarrus mechanism. To study the kinematics and dynamics of the manipulator, the MSC ADAMS program is used, which is one of the most widely used multifunctional computing software. The direct kinematics problem and the inverse dynamics problem of the manipulator are considered and the displacements, velocities and accelerations of the mechanism platform at its spatial translatory movement are obtained, the engine powers required to overcome the force acting on the platform are determined as well. As a special case of the mechanism application, the movement mode for the indirect heart massage has been studied: the realization of artificial respiration with the control of the compressing platform motion, when the platform performs rectilinear translation along one of the coordinate axes. Kinematic parameters are obtained that satisfy the requirements of indirect heart massage and the power needed to overcome the chest resistance force.