| Robots based pick-and-place operations are widely used in automation production.The classical pick-and-place manipulators contain the SCARA serial robot, the Deltaparallel robot, the Par4parallel robot and so on. With the advantages of high speed andhigh acceleration, parallel manipulators have occupied a leading position in market.However, their workspaces are limited. Recently, a co-axis actuated joints arrangementhas been proposed to expand workspace around the base of the mechanism. It is theguarantee for the long span operations. A new planar parallel manipulator with aco-axis actuated joints arrangement is proposed in this thesis. The application of it ispick-and-place operations in automation production.In this thesis, the new parallel manipulator is analyzed; and a new method foroptimal design is proposed. First, the new parallel manipulator is described, and it isdemonstrated to be a3-DOF planar parallel manipulator with differential manifold.Then, the forward and inverse kinematics are discussed with loop-closure equations.According inverse kinematic analysis, the precise formulations of workspace areobtained. After that, singularity is analyzed used Jacobian matrices with geometricalcharacteristics. Next, to estimate the acceleration, the mass matrix is extracted fromkinetic energy equation. For the pick-and-place applications, manipulators need highvelocities and high accelerations so that they can complete the task in the shortestpossible cycle time. At last, the optimal design of the new manipulator uses a newmethod with velocities and accelerations constraints. For optimal kinematic design,velocities constraints are added on the links lengths of the manipulator. Withaccelerations constraints, the links sectional dimensions are obtain in optimal dynamicdesign. The result of the optimal design can meet the high speed and high accelerationrequirements for pick-and-place operation. Also, this optimal method can be applied toother manipulators for pick-and-place operations. |
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