Kinematic-, Static- and Workspace Analysis of a 6-P-U-S Parallel Manipulator

Abstract

This paper examines the symbolic kinematic modeling of a general 6-P-U-S (prismatic-universal-spherical) parallel kinematic manipulator (PKM). The base location of actuators has been previously shown to lead to: (i) reduction of the (motor) weight carried by the legs; (ii) elimination of the actuation transmission requirement (through intermediary joints as in the case of the Stewart-Gough platform); and (iii) most-importantly absorption of reaction-forces by the ground. We focus on using the symbolic equations to derive the conditions for type I and II singularities of this class of parallel manipulators. Based on these conditions, this system of equations is specialized to a specific configuration of the platform that has superior structural design and comparatively minimal singularities within its workspace. A series of studies were conducted to investigate the quality of workspace as well as estimate the actuation requirements for a unit payload carried over their workspace using the symbolic Jacobian model for this specialized configuration.

CAD-enhanced workspace optimization for parallel manipulators: A case study

“…However, our primary interest is to apply this workspace optimization framework to enhance the workspace of a 6-P-U-S parallel manipulator, whose kinematic study was reported in [11][12]. This parallel manipulator consists of six legs, each having a P-U-S architecture as shown in Figure 2 and Figure 3.…”

Data Driven Development of Haptic Models for Needle Biopsy Phantoms

“…This development is examined specifically in the context of deriving controlled force-displacement data from a standard biopsy phantom (called Blue Phantom T M , refer Fig.1(a)). The experiments were conducted using a 6 DOF testing machine [10] that is attached with a 6 DOF force transducer. Development of such a haptic model could then facilitate testing of trainees with either the (i) real phantom (or) (ii) virtual phantom interchangeably using our simulator framework.…”

“…The material characteristics of the BluePhantom T M were determined by performing a series of needle insertion experiments. For this purpose, a 6-DOF robotic platform as in [10], equipped with a 6 DOF force-torque transducer (ATI Delta) is used that served as an effective material testing system (MTS) as shown in Fig.5. The resolution of the force transducer as well as platform translation is summarized in this graph and found to be suitable for our application.…”

Direct Kinematics of a 6-PUS Parallel Robot Using a Numeric-Geometric Method

“…One advantage that this model (6-PUS) has over the traditional 6-UPS is that the actuators remain fixed on the base. In some cases, this simplifies the construction of the robot and, on the other hand, causes part of the payload to be supported by the reaction forces of the floor [9]. Thus, the actuators require less load capacity.…”