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Kinematic Design
Published in Richard Leach, Stuart T. Smith, Basics of Precision Engineering, 2017
A linkage consists of links generally considered as rigid bodies which are connected by joints, such as pivot joints or ball joints. Rigid body means that the body resists deformation so that deformation is insignificant and does not need to be considered as a contributor to the motion of components of the mechanism. Joints serve to constrain the motion of the links or rigid bodies so that they are not free to move with what would otherwise be six degrees of freedom for each rigid body. Constraints are also considered to be ideal so that, for example, a single degree of freedom hinge provides only a relative rotation between two links to which it connects, and no work is required by the joint. A kinematic chain with at least one fixed link is regarded as a mechanism, if at least two other links can move. Linkages can form simple mechanisms and can be designed to perform complex tasks (Rider 2015).
Introduction to Robotic Manipulators
Published in Kevin Russell, Qiong Shen, Raj S. Sodhi, Kinematics and Dynamics of Mechanical Systems Implementation in MATLAB® and Simmechanics®, 2018
Kevin Russell, Qiong Shen, Raj S. Sodhi
As explained in Chapter 1 and demonstrated throughout this textbook, a linkage (also commonly called a mechanism) is an assembly of links and joints where the motion of one link compels the motion of another link in a controlled manner. To enable controlled mechanism motion, they are either initially designed to have a single degree of freedom or ultimately configured (in the case of the geared five-bar mechanism) to have a single degree of freedom. Conventional planar and spatial linkages include the four-bar, slider-crank, geared five-bar, Watt, Stephenson, RRSS, RSSR, and 4R spherical linkages presented in Chapters 4 and 10.
SYSTEMS AND COMPUTER APPLICATIONS
Published in Forrest D. Clark, A.B. Lorenzoni, Applied Cost Engineering, 1996
Wheji systems are linked, it is important to perform sufficient testing in advance to insure that data transfers are error-free. A significant effort is generally required to ensure that data is transferred correctly and, normally, needs to be justified by cost-benefit analysis. A consequence of complex linkages is that systems are necessarily less flexible and more costly to maintain. A number of commercial scheduling packages advertise integrated project management capabilities, but a potential buyer needs to carefully evaluate their limitations as well as their capabilities.
A screw theory approach to compute instantaneous rotation axes of indeterminate spherical linkages
Published in Mechanics Based Design of Structures and Machines, 2020
Juan Ignacio Valderrama-Rodríguez, José M. Rico, J. Jesús Cervantes-Sánchez
It is important to note that the role of the Klein and Killing forms can be drastically modified if the linkages to be analyzed are spherical. In spherical linkages all the kinematic pairs are revolute pairs and their axes all pass through a common point. Without loss of generality, this common point can be chosen as the origin of the coordinate system and therefore the screws representing the revolute pairs, see Eq. (6), can be reduced as
Optimum design and analysis of a novel planar eight-bar linkage mechanism
Published in Mechanics Based Design of Structures and Machines, 2023
Recep Halicioglu, Assylbek Jomartov, Moldir Kuatova
Another alternative to press manufacturing has been the development of different mechanisms to achieve the desired motion gain. These mechanisms have been also driven by a servo motor for flexibility. Soong (2014) developed two types of 1DOF seven-bar geared linkage mechanisms consisted of a slider-crank mechanism or scotch yoke mechanism. In his study, one input cycle was corresponding to two output cycles. Disadvantages of the scotch yoke are the rapid wear of the slot in the yoke and sinusoidal slider motion having a higher forming acceleration. Pennock and Israr (2009) carried out a kinematic analysis and a kinematic synthesis of an adjustable six-bar linkage proposed as a variable-speed transmission mechanism. They tried an angular dwell without slider. He et al. (2010) introduced a turret punch press with an eccentric-toggle mechanism driven by a servomotor for a dwell motion. But a sinusoidal slider motion was obtained without a servo motor. Bai, Gao, and Guo (2011) proposed a design method based on the combination of the dual screw actuation unit, the parallel mechanism with kinematic redundancy, and the toggle mechanism with the symmetric arrangement where screws were driven by multi-servomotors. Losses are likely to be high due to the screw drive and the complexity of the toggle mechanism. Also, lower speed capacity can be considered as a disadvantage of the screw actuations in presses. Halicioglu, Dulger, and Bozdana (2014) conducted a study on the kinematics of a slider-crank mechanism by using Matlab/Simulink platform. They showed that it was possible to extend motion scenarios for the slider with servo inputs. Jomartov et al. studied on the implementation of the four-class kinematic chain to synthesize the crank press mechanism (Jomartov and Tuleshov 2018, 2019; Jomartov et al. 2019; Tuleshov, Jomartov, and Kuatova 2019). Liu et al. (2019) proposed a synthesis strategy for four-bar, six-bar, and eight-bar linkages for a rectilinear movement task and compared the resulting performances of the designs. There are different types of linkage mechanisms in the literature, and they have some disadvantages, such as inability to produce long dwell motion without servo motor or increase in complexity and losses. In addition, since force is transmitted to the slider from a single point in most mechanisms, the unbalanced slider and nonuniformly distributed force affect the forming precision and quality.