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Precise Well-plate Placing Utilizing Contact During Sliding with Tactile-based Pose Estimation for Laboratory Automation

Sameer Pai, Kuniyuki Takahashi, Shimpei Masuda, Naoki Fukaya, Koki Yamane, Avinash Ummadisingu

TL;DR

This work tackles precise placement of a well-plate onto a movable holder, where marker-based pose estimates are uncertain and clearances are sub-millimeter. The authors fuse tactile-based pose estimation using GelSight sensors with a contact-driven sliding strategy that estimates and aligns to the holder's raised groove, achieving sub-millimeter accuracy while keeping the holder stationary. A key addition is an adaptive finger that absorbs external forces to protect tactile sensors and enable robust pose estimation. Experimental results show high success rates even under noisy marker observations and demonstrate the method's applicability to flexible laboratory automation setups.

Abstract

Micro well-plates are an apparatus commonly used in chemical and biological experiments that are a few centimeters thick and contain wells or divets. In this paper, we aim to solve the task of placing the well-plate onto a well-plate holder (referred to as holder). This task is challenging due to the holder's raised grooves being a few millimeters in height, with a clearance of less than 1 mm between the well-plate and holder, thus requiring precise control during placing. Our placing task has the following challenges: 1) The holder's detected pose is uncertain; 2) the required accuracy is at the millimeter to sub-millimeter level due to the raised groove's shallow height and small clearance; 3) the holder is not fixed to a desk and is susceptible to movement from external forces. To address these challenges, we developed methods including a) using tactile sensors for accurate pose estimation of the grasped well-plate to handle issue (1); b) sliding the well-plate onto the target holder while maintaining contact with the holder's groove and estimating its orientation for accurate alignment. This allows for high precision control (addressing issue (2)) and prevents displacement of the holder during placement (addressing issue (3)). We demonstrate a high success rate for the well-plate placing task, even under noisy observation of the holder's pose.

Precise Well-plate Placing Utilizing Contact During Sliding with Tactile-based Pose Estimation for Laboratory Automation

TL;DR

This work tackles precise placement of a well-plate onto a movable holder, where marker-based pose estimates are uncertain and clearances are sub-millimeter. The authors fuse tactile-based pose estimation using GelSight sensors with a contact-driven sliding strategy that estimates and aligns to the holder's raised groove, achieving sub-millimeter accuracy while keeping the holder stationary. A key addition is an adaptive finger that absorbs external forces to protect tactile sensors and enable robust pose estimation. Experimental results show high success rates even under noisy marker observations and demonstrate the method's applicability to flexible laboratory automation setups.

Abstract

Micro well-plates are an apparatus commonly used in chemical and biological experiments that are a few centimeters thick and contain wells or divets. In this paper, we aim to solve the task of placing the well-plate onto a well-plate holder (referred to as holder). This task is challenging due to the holder's raised grooves being a few millimeters in height, with a clearance of less than 1 mm between the well-plate and holder, thus requiring precise control during placing. Our placing task has the following challenges: 1) The holder's detected pose is uncertain; 2) the required accuracy is at the millimeter to sub-millimeter level due to the raised groove's shallow height and small clearance; 3) the holder is not fixed to a desk and is susceptible to movement from external forces. To address these challenges, we developed methods including a) using tactile sensors for accurate pose estimation of the grasped well-plate to handle issue (1); b) sliding the well-plate onto the target holder while maintaining contact with the holder's groove and estimating its orientation for accurate alignment. This allows for high precision control (addressing issue (2)) and prevents displacement of the holder during placement (addressing issue (3)). We demonstrate a high success rate for the well-plate placing task, even under noisy observation of the holder's pose.
Paper Structure (17 sections, 5 equations, 8 figures, 1 table)

This paper contains 17 sections, 5 equations, 8 figures, 1 table.

Table of Contents

  1. Introduction
  2. Related Works
  3. Related Works on Object Placing Task
  4. Related Works on Object Insertion Task
  5. Task Setup
  6. Method
  7. Overview of Pick and Place
  8. Utilization of Tactile Sensors in Pose Estimation
  9. Placing utilizing Contact during Sliding
  10. Experimental Setup
  11. Robot Setup
  12. Custom-designed Parallel Gripper
  13. Experimental Results
  14. Well-plate's Edge Detection using Tactile Sensor
  15. Accuracy of Pose Estimation with Adaptive Finger
  16. ...and 2 more sections

Figures (8)

  • Figure 1: Challenges of placing the well-plate onto the holder
  • Figure 2: Task setup and size of the holder and well-plate.
  • Figure 3: Overview of pick and place, and two key components of our proposed method: pose estimation and placing.
  • Figure 4: Robot setup used for the experiment
  • Figure 5: Comparison of the well-plate edge extraction with and without the use of Depth Map (on a Raw image).
  • ...and 3 more figures