A robotic grasping approach with elliptical cone-based potential fields under disturbed scenes

Wenjie Geng,Zhonghui Li,Zhiqiang Cao,Junzhi Yu,Yingying Yu,Fengshui Jing

doi:10.1177/1729881420985739

Abstract

Vision-based grasping plays an important role in the robot providing better services. It is still challenging under disturbed scenes, where the target object cannot be directly grasped constrained by the interferences from other objects. In this article, a robotic grasping approach with firstly moving the interference objects is proposed based on elliptical cone-based potential fields. Single-shot multibox detector (SSD) is adopted to detect objects, and considering the scene complexity, Euclidean cluster is also employed to obtain the objects without being trained by SSD. And then, we acquire the vertical projection of the point cloud for each object. Considering that different objects have different shapes with respective orientation, the vertical projection is executed along its major axis acquired by the principal component analysis. On this basis, the minimum projected envelope rectangle of each object is obtained. To construct continuous potential field functions, an elliptical-based functional representation is introduced due to the better matching degree of the ellipse with the envelope rectangle among continuous closed convex curves. Guided by the design principles, including continuity, same-eccentricity equivalence, and monotonicity, the potential fields based on elliptical cone are designed. The current interference object to be grasped generates an attractive field, whereas other objects correspond to repulsive ones, and their resultant field is used to solve the best placement of the current interference object. The effectiveness of the proposed approach is verified by experiments.

Highlights

With the rapid development of artificial intelligence, robots are more expected in our daily lives
This article is motivated by the robotic grasping under disturbed scenes, where the target object cannot be grasped directly and we focus on the moving of interference objects by the manipulator
We introduce an elliptical cone EOcojne, which will take effect for a point PO outside El pffiffiffiffiffiffiffi EOj ðEOj

Summary

Introduction

With the rapid development of artificial intelligence, robots are more expected in our daily lives. No The function minbox (wCO1⁄2j) is used to acquire the minimum 3D bounding box BOj along the principal axis direction according to wCO1⁄2j, and VerticalProject (BOj) is to obtain the minimum envelope rectangle of the region, where BOj is vertically projected in OdXdYd. To achieve the grasping under disturbed scenes, the robot should move the interference objects firstly with the consideration of other objects. For any object Oj with its minimum circumscribed ellipse El, the former three items of the design principles are the basis To satisfy these requirements, we introduce an elliptical cone EOcojne, which will take effect for a point PO outside El. For the current grasped object Oig, its elliptical potential field function Fat should conform to the fourth design principle, and it tends to be moved along the short edge direction of projected rectangle. Considering all the objects, we calculate the resultant potential field Fres as follows

Oig wrre1p

Experiments

Conclusion