6,085 research outputs found
Kinematics and workspace analysis of a 3ppps parallel robot with u-shaped base
This paper presents the kinematic analysis of the 3-PPPS parallel robot with
an equilateral mobile platform and a U-shape base. The proposed design and
appropriate selection of parameters allow to formulate simpler direct and
inverse kinematics for the manipulator under study. The parallel singularities
associated with the manipulator depend only on the orientation of the
end-effector, and thus depend only on the orientation of the end effector. The
quaternion parameters are used to represent the aspects, i.e. the singularity
free regions of the workspace. A cylindrical algebraic decomposition is used to
characterize the workspace and joint space with a low number of cells. The
dis-criminant variety is obtained to describe the boundaries of each cell. With
these simplifications, the 3-PPPS parallel robot with proposed design can be
claimed as the simplest 6 DOF robot, which further makes it useful for the
industrial applications
A modal approach to hyper-redundant manipulator kinematics
This paper presents novel and efficient kinematic modeling techniques for âhyper-redundantâ robots. This approach is based on a âbackbone curveâ that captures the robot's macroscopic geometric features. The inverse kinematic, or âhyper-redundancy resolution,â problem reduces to determining the time varying backbone curve behavior. To efficiently solve the inverse kinematics problem, the authors introduce a âmodalâ approach, in which a set of intrinsic backbone curve shape functions are restricted to a modal form. The singularities of the modal approach, modal non-degeneracy conditions, and modal switching are considered. For discretely segmented morphologies, the authors introduce âfittingâ algorithms that determine the actuator displacements that cause the discrete manipulator to adhere to the backbone curve. These techniques are demonstrated with planar and spatial mechanism examples. They have also been implemented on a 30 degree-of-freedom robot prototype
Parametric stiffness analysis of the Orthoglide
This paper presents a parametric stiffness analysis of the Orthoglide. A
compliant modeling and a symbolic expression of the stiffness matrix are
conducted. This allows a simple systematic analysis of the influence of the
geometric design parameters and to quickly identify the critical link
parameters. Our symbolic model is used to display the stiffest areas of the
workspace for a specific machining task. Our approach can be applied to any
parallel manipulator for which stiffness is a critical issue
A hyper-redundant manipulator
âHyper-redundantâ manipulators have a very large number of actuatable degrees of freedom. The benefits of hyper-redundant robots include the ability to avoid obstacles, increased robustness with respect to mechanical failure, and the ability to perform new forms of robot locomotion and grasping. The authors examine hyper-redundant manipulator design criteria and the physical implementation of one particular design: a variable geometry truss
A Novel Approach for Simplification of Industrial Robot Dynamic Model Using Interval Method
This paper proposes a new approach to simplify the dynamic model of industrial robot by means of interval method. Due to strong nonlinearities, some components of robot dynamic model such as the inertia matrix and the vector of centrifugal, Coriolis and gravitational torques, are very complicated for real-time control of industrial robots. Thus, a simplification algorithm is presented in this study in order to reduce the computation time and memory occupation. More importantly, this simplification is suitable for arbitrary trajectories in whole robot workspace. Furthermore, the method devotes to finding negligible inertia parameters, which is useful for robot model identification. A simulation has been carried out on a test trajectory using a 6-DOF industrial robot model, and the results have shown good performance and effectiveness of this method.ANR COROUSS
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