Kinematic analysis of a novel 3-CRU translational parallel mechanism

Abstract

Abstract. In this paper, a modified 3-DOF (degrees of freedom) translational parallel mechanism (TPM) three-CRU (C, R, and U represent the cylindrical, revolute, and universal joints, respectively) structure is proposed. The architecture of the TPM is comprised of a moving platform attached to a base through three CRU jointed serial linkages. The prismatic motions of the cylindrical joints are considered to be actively actuated. Kinematics and performance of the TPM are studied systematically. Firstly, the structural characteristics of the mechanism are described, and then some comparisons are made with the existing 3-CRU parallel mechanisms. Although these two 3-CRU parallel mechanisms are both composed of the same CRU limbs, the types of freedoms are completely different due to the different arrangements of limbs. The DOFs of this TPM are analyzed by means of screw theory. Secondly, both the inverse and forward displacements are derived in closed form, and then these two problems are calculated directly in explicit form. Thereafter, the Jacobian matrix of the mechanism is derived, the performances of the mechanism are evaluated based on the conditioning index, and the performance of a 3-CRU TPM changing with the actuator layout angle is investigated. Thirdly, the workspace of the mechanism is obtained based on the forward position analysis, and the reachable workspace volume is derived when the actuator layout angle is changed. Finally, some conclusions are given and the potential applications of the mechanism are pointed out.

Kinematic design of a translational parallel mechanism based on sub-kinematic chain determined workspace superposition

“…For instance, a class of typical TPMs consists of three UPU 1 or PUU kinematic linkages [14]- [17] . Another approach to construct the TPMs is commonly to adopt the C-joint [18] in the kinematic linkages, say 3-URC [19] [20] , 3-PRC [21] [22] , 3-CPU [23] , etc. When the three linkages are arranged with a Cartesian configuration, i.e., the actuated joints located in three perpendicular planes, the TPMs can have the characteristics of completely decoupled motions and kinematic isotropy [24]- [26] .…”

Kinematics Comparative Study of Two Overconstrained Parallel Manipulators

“…Qi et al [15] discussed the kinematic optimum design of the 3-PUS/PU with 1T2R DOFs PM. Apart from the mixed 3-DOF PMs mentioned above, some other similar 3-DOF structures can be seen in the literature [16][17][18][19].…”

Concept Design and Analysis of a Novel Steamer-Filling Robot

“…According to (2), given a set of ( 1 , 2 ), the position coordinate ( , ) of the end of the robot can be calculated directly, which is the forward position solution of the mechanism. Here, 1 = ‖ ‖, 2 = ‖ ‖.…”

“…In order to get the inverse positon analysis of the robot, from (2), an equation about the relation between the parameters of 1 , 2 and , can be deduced as follows:…”

“…These technical methods can be divided into two categories, namely, nonrobot method and robot method [1][2][3][4]. For the nonrobot method, some conventional conveying devices, such as conveyor belt, are used to fill fermenting grains into fermentation containers.…”