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Fundamental Concepts in Kinematics
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
Mechanism links are interconnected by joints. Both the planar four-bar, geared five-bar, Watt, and Stephenson mechanisms include revolute joints: joints having a single rotational degree of freedom. The prismatic joint has a single translational degree of freedom and is used where 1-DOF sliding contact is needed. The cylindrical joint and spherical joint are other joint types utilized in spatial mechanisms. The cylindrical joint has a rotational and a translational degree of freedom, while the spherical joint has three rotational degrees of freedom. Joints having two degrees of freedom include the cam joint and gear joint, which both include rolling-sliding contact.
Manipulator Kinematics
Published in Richard M. Murray, Zexiang Li, S. Shankar Sastry, A Mathematical Introduction to Robotic Manipulation, 2017
Richard M. Murray, Zexiang Li, S. Shankar Sastry
The revolute, prismatic, and helical joints each correspond to screw motions, with the helical joint corresponding to a general screw with finite, nonzero pitch. A cylindrical joint has two independent degrees of freedom and is typically constructed by combining a revolute and a prismatic joint such that their axes are coincident. Revolute and prismatic joints are by far the most common type of joint encountered in robotics.
RoamFab: A Design Tool for Reconfiguring Parameterized Mechanisms to 3D Models With Structural Optimization
Published in International Journal of Human–Computer Interaction, 2022
Shijian Luo, Zhitong Cui, Jiancheng Gu, Ting Chen, Chengyi Shen, Yang Lu, Yanan Wang, Preben Hansen
To enable two objects to rotate relative to each other, RoamFab provides three types of hinge mechanisms shown in Figure 1. The first hinge mechanism embeds two separated parts for revolute motion and can be 3D printed in place along the rotating axis. For conditions where the user needs to assemble a hinge manually, we provide the second hinge mechanism consisting of three parts, where the ISO metric screw thread is used to hold the two parts together. The third hinge mechanism, also known as a cylindrical joint with two degrees of freedom, can be used when the user does not need the limit parts at both ends of the rotating shaft to provide a single-axis sliding function. Essential design for hinge mechanisms is the printing tolerance between the inner part and the outer part that allows them to hinge.
Inertia dynamics of the Myard RCRCR constant-velocity coupling
Published in Mechanics Based Design of Structures and Machines, 2020
For an intermediate cylindrical joint the force component Fn+1,k and torque component Tn+1,k are considered negligible since in the absence of friction loads aligned with the joint’s degrees of freedom cannot be transmitted. Consequently, Eq. (10) expanded into its primary and dual components becomes which can be rewritten in the form of Eqs. (13) and (14) where and factor is a 3 × 2 null matrix since the force components of the loads on a simple joint n + 1 pass through the origin of frame {n + 1}, and the , and terms are trivial.
An improved approach to the inverse dynamic analysis of parallel manipulators by a given virtual screw
Published in Advanced Robotics, 2018
As shown in Figure 2, a PM is constituted of three modules: static platform, moving platform and more than one limb between the two platforms. The static platform is fixed, and the expected motion of moving platform is controlled by the driving components of active limbs. Usually, the components of each limb called link are connected by kinematic joints, such as prismatic joint denoted by P, revolute joint denoted by R and etc. Meanwhile, other kinematic joints can be expressed as the combination of revolute joints and prismatic joints, so the revolute joint and prismatic joint are called basic joints. For instance, universal joint denoted by U is equal to two revolute joints, spherical joint denoted by S can be replaced by three revolute joints, and cylindrical joint denoted by C is the combination of one revolute joint and one prismatic joint.