Double Circular-Triangular Six-Degrees-of-Freedom Parallel Robot

Abstract

This paper describes a new structure of a six-DOF parallel robot. First, a known planar three-DOF double-triangular structure is modified by replacing the stationary triangle with a circle. It increases the work envelope considerably especially when rotational motions are required. The ability for unlimited rotational motion allows extending the structure into six-DOF by using two sets of stationary circles and moveable triangles. Each set can actuate the moving triangle in a planar three-DOF motion and hence actuate a line connecting the centers of the movable triangles in four-DOF. The robot's end-effector is attached to a link along this line while rotation about and translation along this line are obtained by the additional rotational DOF of the movable triangles. The solution of the direct kinematics of this six-DOF manipulator is given in a closedform and it is shown that at most, four different solutions exist.

A Robotic System with a Hybrid Motion Cueing Controller for Inertia Tensor Approximation in Micro-Manipulations

“…Some of the kinematic structures have linear motors at the base moving along a triangle as presented in [29] providing three DOFs, whereas 6-DOF utilizes rotational actuators as demonstrated in [30]. Another study describing a design with linear motion and a screw-like motion of the moving platform is shown in [31].…”

A novel five-degrees-of-freedom decoupled robot

“…[30][31][32][33][34][35] However, in such mechanisms not all the active limbs can be attached at the fixed platform. On the other hand, the robot introduced here differs from the double circular-triangular 6-DOF parallel robot proposed by Brodsky et al 22 in that such mechanism is formed with two serially connected 3-DOF planar mechanisms; where each planar mechanism consists of a circular-triangular combination, in which the triangle is connected at the circle by means of three sliders pivoted on axes, with such architecture only three of the six active joints can be attached at the fixed platform. In fact, the design of Brodsky et al 22 requires that active limbs must be attached at the upper moving platform, with its corresponding servos.…”

“…In this work a novel decoupled robot, called LinceJJP, formed from an inner serial-parallel manipulator and an external parallel manipulator, with a common moving platform in which, unlike the contributions of Brodsky et al 22 and Austad, 23 all the active limbs are attached at the fixed platform is introduced.…”

Stiffness Synthesis of a Variable Geometry Six-Degrees-of-Freedom Double Planar Parallel Robot

“…Figure 2 shows the variable geometry DP robot based on two similar planar units as in Figure 1. These planar units constitute a variation over the Double Circular-Triangular (DCT) robot presented in Simaan, Glozman, and Shoham (1998) and Brodsky, Glozman, and Shoham (1998), which, in its turn, is Daniali, Zsombar-Murray, and Angeles (1993). The two planar units of the DP robot control the position and orientation of their moving platforms by changing the lengths of their prismatic joints and the location of the sliders on their circular bases.…”