Zero moment two edge pushing of novel objects with center of mass estimation

Published in IEEE Transactions on Automation Science and Engineering, 2022

🤖 Zero Moment Two Edge Pushing (ZMTEP)

Nonprehensile manipulation for precise object translation without rotation using center of mass estimation

Robot Manipulation Pushing Nonprehensile Manipulation Center of Mass Estimation Motion Control

📋 Overview

This work addresses the challenge of translating novel objects to goal positions without causing undesired rotations. By combining center of mass estimation with the Zero Moment Two Edge Pushing (ZMTEP) strategy, the method enables a robot manipulator to achieve precise object positioning even with unknown object properties. The approach leverages the concept of zero moment manipulation, where pushing forces are applied at specific contact points to ensure pure translational motion.

Key Contributions

Development of Zero Moment Two Edge Pushing (ZMTEP) method for rotation-free translation
Integration of center of mass estimation with pushing strategy selection
Methodology applicable to novel objects without prior geometric or physical knowledge
Experimental validation on diverse object geometries
Practical framework for robotic nonprehensile manipulation tasks

🎨 Methodology

The Zero Moment Two Edge Pushing method selects pushing configurations based on the estimated center of mass and desired motion direction. By applying forces at two strategically chosen contact edges while maintaining zero moment about the object’s center, the method ensures pure translational motion without rotation.

 Key Concept: The method pushes at two contact points positioned symmetrically with respect to the center of mass projection, creating equal and opposite moment components that cancel out, resulting in pure translation to the goal position.

📊 Visual Summary

Poster: Visual summary of this work. Download PDF

🎥 Pushing Priors Collection Procedure

Procedure for Collecting Pushing Priors and CoM Estimation

Description: This video demonstrates the procedure for collecting pushing priors used in learning object motion dynamics. The robot systematically performs pushing interactions at various contact points and directions on the object surface. Through these interactions, the system learns how the object responds to different pushing actions and configurations. At the end of the procedure, the estimated center of mass is computed and displayed, showing how the accumulated pushing data is used to accurately determine the object's center of mass without prior knowledge of the object's properties.

🎯 Object Translation to Target Location

Object Translation using Zero Moment Two Edge Pushing

Description: This video demonstrates the Zero Moment Two Edge Pushing (ZMTEP) method applied to translate an object to a target location. Based on the estimated center of mass and the desired goal position, the robot applies coordinated pushing forces at two strategic contact points. These pushing configurations are designed to create equal and opposite moments that cancel out, resulting in pure translational motion without any unwanted rotation. The object is precisely guided from its initial position to the target location, demonstrating the effectiveness of the ZMTEP strategy in achieving rotation-free object manipulation.

Ziyan Gao