1 Department of Mechanical Engineering, University of Tabriz, Tabriz, Iran. 2 School of Engineering Emerging Technologies, Mechatronics Laboratory, University of Tabriz, Tabriz, Iran. Corresponding author Email: [email protected] Abstract: In the design of parallel manipulators, usually mean value of a dexterity measure over the workspace volume is considered as the objective function to be...

In this article we present a comparison study of the robustness properties of three model-based nonlinear controllers for cooperative underactuated manipulators. Two of the controllers are based on feedback linearization of the nonlinear dynamic coupling between the torques applied at the actuated joints and the Cartesian acceleration of the load. The third is based on a gravity compensation sc...

Parallel manipulators which are singular with respect to the Schönflies motion group X(a) are called Schönflies-singular, or more precisely X(a)-singular, where a denotes the rotary axis. A special class of such manipulators are architecturally singular ones because they are singular with respect to any Schönflies group. Another remarkable set of Schönflies-singular planar parallel manipulators...

For conventional designs of robots, manipulator motions result in forces and moments on the base. These forces and moments may cause undesirable translation and rotation of the base. The objective of this paper is to systematically analyze the fundamentals of reactionless robots. Based on this analysis, designs of two distinct classes of spatial robots are proposed. The designs are achieved thr...

Parallel manipulators offer much higher rigidity and smaller mobile mass than their serial counterparts, thus allowing much faster and more precise manipulations. The main disadvantage of parallel robots is their small workspace in comparison to serial arms of similar size. Furthermore, the manipulability of parallel robots is often poor in some regions of the (already small) workspace. Another...

The axially translating flexible link in flexible manipulators with a prismatic joint can be modeled using the Euler-Bernoulli beam equation together with the convective terms. In general, the method of separation of variables cannot be applied to solve this partial differential equation. In this paper, we present a nondimensional form of the Euler-Bernoulli beam equation using the concept of g...

Positioning 3R manipulators may have two or four inverse kinematic solutions (IKS). This paper derives a necessary and sufficient condition for 3R positioning manipulators with orthogonal joint axes to have four distinct IKS. We show that the transition between manipulators with 2 and 4 IKS is defined by the set of manipulators with a quadruple root of their inverse kinematics. The resulting co...

There are mainly two types of the manipulators: serial manipulators and parallel manipulators. The serial manipulators are open-ended structures consisting of several links connected in series. Such a manipulator can be operated effectively in the whole volume of its working space. However, as the actuator in the base has to carry and move the whole manipulator with its links and actuators, it ...

Current industrial robots are made very heavy to achieve high Stiffness which increases the accuracy of their motion. However this heaviness limits the robot speed and in masses the required energy to move the system. The requirement for higher speed and better system performance makes it necessary to consider a new generation of light weight manipulators as an alternative to today's massive in...

Parallel manipulators feature relatively high payload and accuracy capabilities compared to their serial counterparts. However, they suffer from small workspace and low maneuverability. Kinematic redundancy for parallel manipulators can improve both of these characteristics. This paper presents a family of new kinematically redundant planar parallel manipulators with six actuated-joint degrees ...