Precise dispensing of liquids using visual feedback

Abstract

Robotic pouring is an important step in improving the safety, productivity and repeatability in the biotechnology industry and generally increasing the effectiveness of robotics in human based environments. In this work we present a method to autonomously dispense a precise amount of fluid using only visual feedback without using precision pouring instruments such as pipettes, syringes or pourers. We model circular and rectangular pouring container geometries. We prove that for square containers we can control the flow by only observing the fluid height in the receiving beaker. We show a systematic approach using a hybrid control scheme that is robust to the initial amount of fluid in the pouring container and inconsistent flow. Specifically we present (a) a model for pouring (b) a model based algorithm to drive a robot arm (c) visual feedback for regulating the pouring rate. We demonstrate this using the Rethink Robotics Sawyer manipulator and mvBluefox MLC202bc camera.