Unified Kinematics of Prismatically Actuated Parallel Delta Robots

Abstract

SummaryThis paper presents a unified formulation for the kinematics, singularity and workspace analyses of parallel delta robots with prismatic actuation. Unlike the existing studies, the derivations presented in this paper are made by assuming variable angles and variable link lengths. Thus, the presented scheme can be used for all of the possible linear delta robot configurations including the ones with asymmetric kinematic chains. Referring to a geometry-based derivation, the paper first formulates the position and the velocity kinematics of linear delta robots with non-iterative exact solutions. Then, all of the singular configurations are identified assuming a parametric content for the Jacobian matrix derived in the velocity kinematics section. Furthermore, a benchmark study is carried out to determine the linear delta robot configuration with the maximum cubic workspace among symmetric and semi-symmetric kinematic chains. In order to show the validity of the proposed approach, two sets of experiments are made, respectively, on the horizontal and the Keops type of linear delta robots. The experiment results for the confirmation of the presented kinematic analysis and the simulation results for the determination of the maximum cubic workspace illustrate the efficacy and the flexible applicability of the proposed framework.

Evaluation of Topological Properties of Parallel Manipulators Based on the Topological Characteristic Indexes

“…16 Moreover, Wenger proposed the Orthoglide robot 17 that evolved from the Tsai mechanism by replacing the revolute joints with prismatic joints and changing the organization of the three chains. 18 Obviously, the DOF, POC sets and coupling degree k of these revised mechanisms remain the same as those of the original Delta.…”

Design of 3DOF Delta Parallel Capture Robot with High Speed and Light Weight

“…The Pierrot team invented a 4 branched parallel Delta robot called Par4 whose operator has the acceleration 12 g, experimental acceleration 20 g. Miller changed the driving direction of motors which made the experimental acceleration to 20 g. At present, with the feature of high environmental adaptability, light weight, high speed and high accuracy, Delta parallel robot is the most successful and most widely used parallel robot [5][6][7]. As sensors and machine vision added to robot body, the accuracy of parallel robot has improved greatly [8][9][10].The mature products of some giant companies such as Aemk, ABB and Fanuc have the operator acceleration up to more than 10g, and the grabbing speed up to more than 200 time/min, and repeated positioning accuracy less than 0.5 mm even without machine vision. In China, theoretical researches are more valued and only a few companies (seasun) have mature products whose capture speed is 200 time/min [11][12][13].…”