A study of the singularity locus in the joint space of planar parallel manipulators: special focus on cusps and nodes

Cusps and nodes on plane sections of the singularity locus in the joint space of parallel manipulators play an important role in nonsingular assembly-mode changing motions. This paper analyses in detail such points, both in the joint space and in the workspace. It is shown that a cusp (resp. a node) defines a point of tangency (resp. a crossing point) in the workspace between the singular curves and the curves associated with the so-called characteristics surfaces. The study is conducted on a planar 3-RPR manipulator for illustrative purposes.Comment: 4th International Congress Design and Modeling of Mechanical Systems, Sousse : Tunisia (2011

Singularity Surfaces and Maximal Singularity-Free Boxes in the Joint Space of Planar 3-RPR Parallel Manipulators

In this paper, a method to compute joint space singularity surfaces of 3-RPR planar parallel manipulators is first presented. Then, a procedure to determine maximal joint space singularity-free boxes is introduced. Numerical examples are given in order to illustrate graphically the results. This study is of high interest for planning trajectories in the joint space of 3-RPR parallel manipulators and for manipulators design as it may constitute a tool for choosing appropriate joint limits and thus for sizing the link lengths of the manipulator

A Method of Energy-Optimal Trajectory Planning for Palletizing Robot

In this work, the energy-optimal trajectory planning and initial pick point searching problem for palletizing robot with high load capacity and high speed are studied, in which the pick point and place point of the robot are fixed to a desired location for each single task. These optimization problems have been transformed to ternary functional extremum problem and parameters optimal selection problem in which the performance index of the problems the rigid-flexible coupling dynamics model of the robot, and the constraint and boundary conditions of the robot are given. The fourth-order Runge-Kutta method, multiple shooting method, and traversing method are used to solve these specific mathematical problems. The effectiveness of the trajectory planning method is validated by the experimental and simulating results; thus the research work done here provides important support for subsequent palletizing robot research

Design of reconfigurable planar parallel robot

A 3-RPR planar parallel robot is a kind of planar mechanism; three prismatic actuators connected with the end effector in parallel. This thesis will begin with the kinematic analysis for the manipulator to determinate the optimized dimension of the manipulator, including the workspace analysis, determinate of Jacobian analysis, and Direction Selective Index (DSI) analysis. Secondly, a multi-body bond graph system will be built for the 3-RPR planar parallel manipulator (PPM), along with three PID controllers, which give commands to three DC motors respectively. The advantage of bond graphs is that they can integrate different types of dynamics systems. The manipulator, the control and the motor can be modelled and simulated altogether in the same process. The bond graph will be established for each rigid body with body-fixed coordinate’s reference frames, which are connected with parasitic elements (damping and compliance) to each other. Furthermore, Virtual Work method will be used to evaluate the previous dynamic analysis result. Eventually, the Solidworks design will be demonstrated with images, which show the overall appearance and a detailed drawing of this project. After the mechanical design of the manipulator is finished, the controller design is considered as a future work to conduct