Kinetostatic design and development of a non-fully symmetric parallel Delta robot with one structural simplified kinematic linkage

Abstract

In this work, the structural design of a structure-simplified parallel Delta robot is presented, by considering the kinetostatics, kinematic dexterity and workspace. An approach to normalize the dimensionally inhomogeneous Cartesian stiffness matrix is introduced, and a stiffness evaluation index is defined by means of the singular value decomposition of homogenized stiffness matrix, which is used in the design optimization in turn. A multi-objective design optimization problem is formulated to provide the optimal solutions of different sets of geometric parameters. A set of parameters is selected to lay out the robot, and the tested specifications show the good performances, although the speed is not so high as the commercial FlexPicker and Quattro. A comparative study is carried out between the proposed and original Delta robots by observing joint dynamics, showing that the modified robot structure can improve the robot dynamics. The presented work turns out that the proposed robot is applicable to the pick-and-place operations without high-precision requirement in most industrial sectors.

Keywords:

• parallel Delta robot
• pick-and-place application
• structural simplification
• kinetostatics
• multi-objective design optimization

Acknowledgment

The financial supports from National Natural Science Foundation of China (51975062) and China Scholarship Council (CSC No. 201906065026) are gratefully acknowledged.

Notes

1 The trajectory is defined as the movement along a trajectory of 25 mm × 305 mm × 25 mm with a 1kg payload defined in (Wu et al. 2020), which can also be a trajectory of 25 mm × 300 mm × 25 mm instead in the definition of Adept test cycle (Gauthier, Angeles, and Nokleby 2008).