Quantitative motion detection of in-hand objects for robotic grasp manipulation

Xueyong Li,Kai Zhao,Yonghui Wang,Changhou Lu

doi:10.1177/1729881419846336

Abstract

In an actual grasp operation, grasp accidents (slant, rolling, turning over, and dropping) of in-hand objects occur frequently. Quantitative motion detection of in-hand objects is critical to optimize the grasp configuration and to improve the stability and dexterity of a grasp manipulation. In this article, an innovative method for quantitative measurement of the motions of in-hand objects is presented. Firstly, the slip information at object–finger interface between adjacent states is detected by three omnidirectional slip sensors; next, singular value decomposition method is applied to calculate the rotation and translation matrices according to the relative coordinate changes extracted from the slip information. Finally, Euler angles and the linear displacements which illustrate the motion of in-hand objects are quantitatively measured from the translation matrix and the rotation matrix, and the continuous motion track can be further established. Experiment results show that the proposed method is effective in detecting multiple motion information of in-hand objects.

Highlights

Stable and safe grasp in an unstructured environment is still one of the biggest challenges for grasp robotics
The average of the absolute error qxerror computed by equation (14) is 0.04 and the average relative error rate dxerror calculated by equation (16) is 1.6%
We present a novel method to quantitatively measure the motions of in-hand objects

Summary

Introduction

Stable and safe grasp in an unstructured environment is still one of the biggest challenges for grasp robotics. To get a successful grasp, most of the studies[1,2,3] give their emphases on the grasp planning, namely, determining contact points of the finger on the object and formulating an appropriate gripper configuration. These researches attempt to acquire the optimal grasp planning based on the information of the object and the gripper obtained before grasp operation. When exerting this optimal grasp planning in a real grasp operation, accidents, such as slip, slant, rolling, turning over, and even drop, frequently occur, because the grasp planning built in advance is based on ideal conditions and is inevitably affected by the actual working environment and factors.

Methods

Results

Discussion

Conclusion