2020. 2. 17. 07:57ㆍ카테고리 없음
KinematicsThe study of Kinematics of mechanisms and the machines, which are composed of one or more mechanisms, involves analysis of geometry of motion. Different components of any mechanism move relative to the each other following certain constraints to produce the desired motion. Kinematic analysis is of prime importance in design of mechanisms and machines.For kinematic design of a mechanism analysis is done for positions of points on a solid body and the time derivatives of the position. The first derivative of position with respect to time is velocity, the second derivative is acceleration and further derivatives can be analyzed according to the design requirements.
Similarly for angular position there is angular velocity and angular acceleration. MechanismsThe simplest example for a mechanism will be a liver hinged at a wedge.
It transfers input motion at one end to the output motion on the other end. A scissors is a combination of two livers; the mechanical work from one end can be transformed to cutting motion on the output end. The two livers in scissors are connected together by a joint (revolute joint). A slightly more complex mechanism is a slider crank mechanism.Thus mechanisms can be defined as assembly of rigid members connected to each other through joints.
A mechanism transfers the input motion or work at the input point or point of actuation to one or more output points. Like in case of slider crank mechanism, the input rotational motion of the crank is transferred to the slider as a reciprocating motion.
Simple Mechanisms. Kinematic JointsThe members in a mechanism are connected by kinematic joints.
A kinematic joint is formed by direct contact between the surfaces of the members forming that joint. The contact between the surfaces of the members can be point contact, line contact or area contact. The joints are classified according to the type of contact and relative motion of the members. The contact stresses developed will also depend on the contact type.There are two types of joints according to the type of contact:1. Lower pair joint2. Higher pair jointLower pair joint has area contact between the two mating surfaces of the members forming joint, as in the case for slider, revolute and hinge.Higher pair joint has the contact between the mating surfaces as point or line contact as in the case for cam pair and cam-follower.Following sections will discuss basics of analysis and synthesis of mechanisms. ReferencesBook: Theory of Mechanisms and Machines – Ghosh and MallikBook: Kinematics, Dynamics and Design of Machinery – Waldron and Kinzel This post is part of the series: Kinematics – Design of Mechanisms.
A new three degrees of freedom (3-DOF) translational parallel manipulator (TPM) with fixed actuators called a 3-PRC TPM is proposed in this paper. The mobility of the manipulator is analyzed via screw theory. The inverse kinematics, forward kinematics, and velocity analysis are performed and the singular and isotropic configurations are identified afterward.
Kinematics Spatial Mechanisms Pdf Printer Driver
Moreover, the mechanism design to eliminate all singularities and generate an isotropic manipulator has been presented. With the variation on architectural parameters, the reachable workspace of the manipulator is generated and compared.
Especially, it is illustrated that the manipulator in principle possesses a uniform workspace with a constant hexagon shape cross section. Furthermore, the dexterity characteristics are investigated in the local and global sense, respectively, and some considerations for real machine design have been proposed as well.