Spherical Joint
球面接头

Spherical Joint(球面接头)研究综述

Spherical Joint 球面接头 - This paper presents a complete kinematic model of the tibiofemoral joint based on a RRPP + 4-SPS parallel mechanism, where R, P and S stands for revolute, prismatic and spherical joints respectively. ^[1] For understanding better the overall deformation behaviors of solder joins, especially the strain–stress relationship, uniaxial compression experiments of spherical joint-scale granules were conducted under different loading rates. ^[2] The coupling is equivalently modeled as a 7-SPS parallel mechanism, the spherical joints of which represent centers of supporting balls and contact points, and prismatic joints are used to simulate the deformations. ^[3] Articulations between ribs and the sternum were defined as spherical joints except in the ninth and tenth pairs, which have one additional anteroposterior degree-of-freedom. ^[4] Based on the kinematic evaluations, a preferred configuration of 2U P R-1R P S PM (‘R’: revolute joint, ‘U’: universal joint, ‘S’: spherical joint, ‘ P ’: prismatic actuated joint) is selected as a candidate for 1T2R spindle head. ^[5] a ball-on-plate contact and a spherical joint, are considered. ^[6] This paper proposes a measurement method for the rotation angle of the spherical joint based on the extreme learning machine (ELM) artificial neural network and four eddy current sensors. ^[7] This paper demonstrates a successful implementation of a deep reinforcement learning algorithm on an inverted pendulum that rotates freely on a spherical joint with an industrial 6 degrees freedom robot arm. ^[8] From these models, predicted failure load was determined for two different boundary conditions: fixed support and spherical joints. ^[9] In order to meet the requirements of the antenna pedestal for supporting and driving antenna to complete specific trajectory movement, the PU-2UPS parallel mechanism is proposed for antenna pedestal, where P, U and S represent the prismatic joint, universal joint and spherical joint, respectively. ^[10] This path is optimized through minimization algorithms restricted by distance, velocity and acceleration of the linear actuators of the robot, as well as the working space of its spherical joints. ^[11] Methods: The microrobot is fabricated with a spherical joint and a guidewire. ^[12] It is composed of three tendon-actuated continuum robots as kinematic chains that are coupled at a common end-effector platform by spherical joints. ^[13] This paper proposes the nonsingular design principle, which can completely eliminate constraint/actuation singularity in parallel mechanism (PM), and accordingly designs a nonsingular redundant 2RPS-UPU+2SPS (R: revolute joint, P: actuated prismatic joint, S: spherical joint, U: universal joint) leg mechanism with RxRyTz DOF (Rx: rotational DOF around x, Ry: rotational DOF around y, Tz: translational DOF along z, DOF: degree of freedom). ^[14] Because of the low friction torque of the spherical joint in the SMMB, the rotation is not able to be wholly transferred from base to rotor, which is required in the common method of velocity-attitude matching. ^[15] presented an admittance control method under a master–slave architecture for quadrotors carrying a heavy payload via spherical joints or short cables, which implies that the quadrotor attitude motions are decoupled from the payloadmotion [10]. ^[16] To solve complex problems via the kinematics analysis of tensegrity parallel mechanism, a method based on the variable-step fish swarm algorithm was proposed, and the kinematics of the spherical joint-prismatic joint-spherical joint (3-SPS) tensegrity parallel mechanism was studied. ^[17] Spherical joints are frequently used in the construction of PKMs; however, spherical joints have a unique physical constraint, known as cone angle limit, around their axis of symmetry. ^[18] The mechanical motion rectifier comprises of a spatial mechanism with unidirectional bearings and spherical joint that converts the linear oscillating force into unidirectional torque pulses. ^[19] A novel hybrid perfusion manipulator (HPM) with five degrees of freedom (DOFs) is introduced by combining the 5PUS-PRPU (P, R, U, and S represent prismatic, revolute, universal, and spherical joint, respectively) parallel mechanism with the 5PRR reconfigurable base to enhance the perfusion efficiency of the large-scale spherical honeycomb thermal protection layer. ^[20] In previous numerical models developed for the impact dynamic responses of reticulated domes, mostly BEAM 161 elements and piecewise linear plastic material model have been employed and spherical joints have been simplified as intersection points of beams, which is called the B-P method. ^[21] The space robot consists of a service satellite and a robotic manipulator comprising an arbitrary number of rigid links connected by spherical joints. ^[22] The central joint due to its coincidental nature of the rotational axes provides features similar to a spherical joint. ^[23] By this mean, the Euler angles computation of spherical joints is avoided, and the coordinate transformation equation of spatial linkages which contain varied kinds of joints can be solved more easily and efficiently. ^[24] There are three possible kinematic implementations of spherical joints: serial, parallel, and hybrid, each one with its own advantages and disadvantages. ^[25] To capture the characteristics human body motion using experimental data, one often needs to initially assume joints with three rotational degrees of freedom (spherical joints). ^[26] According to the required degrees of freedom (DoFs), a parallel mechanism with the configuration of 4SPU-SPR (S, spherical joint; P, prismatic joint; U, universal joint; R, revolute joint) is proposed by using the type synthesis method based on Grassmann Line Geometry and Line-graphs. ^[27] The proposed latching mechanism is based on the spherical joint (ball and socket) that allows rotation and free movements in two planes at the same time. ^[28] Nevertheless, the inherent errors of both the components themselves and the posture alignment system lead to high risk of collision during the inserting stage, among which the positional errors of spherical joints that connecting the large component to the numerical controlled locators are identified as the primary error source by existing studies. ^[29] The elastostatic stiffness performance of a 2PUR-PSR (S: spherical joint; U: universal joint; R: revolute joint; P: prismatic pair) overconstrained parallel mechanism with two rotational and one translational (2R1T) degrees of freedom was studied based on screw theory and strain energy. ^[30] The contact constraints are imposed first through distances between the fingers and the object surfaces and then through spherical joints. ^[31] As a verification, the equation of motion for the mechanism is applied to the case of one body attached to the ground by a spherical joint of which the close form solution is known. ^[32] Two constraint models of spherical joints with clearances were introduced to facilitate the investigation of the behavior of joint elements. ^[33] METHODS: The reverse coordinate system method is applied to solve inverse kinematics of the exoskeleton with a non-spherical joint in the wrist. ^[34] Spherical joint is provided with three dimensional rotation motion, which has been widely applied in robots, parallel mechanisms, automobiles and medical devices on account of its smooth motion, compact structure, high load capacity. ^[35] Its each branch chain consists of spherical joint, revolute joint and prismatic joint, in which the prismatic joint is driven by the cylinder. ^[36] The closure equations are formulated in the three-dimensional Euclidean spaces considering the coordinates of the centers of the spherical joints as unknown variables. ^[37] This paper presents a 3-RPaS (R and S denote the revolute and spherical joint, pa denotes the parallelogram) parallel manipulator with two-rotational-degrees-of-freedom (2R1T) and one-translational-degree-of-freedom motion. ^[38] Meanwhile, a compound joint consisting of hook and rotary joints is substituted for the spherical joint of the solar tracker to overcome its inadequate rotational range and facilitate fabrication. ^[39] Among the linear motions, the Y and Z-motion transferred to the holder tip through a spherical joint. ^[40] Due to the flexible and compact structures, spherical joints are widely used in parallel manipulators and industrial robots. ^[41]