Worm Picker 2.0

Task-based motion control architecture for C. elegans manipulation
Motion‑control architecture developed for Logan Kaising's 2025 honors thesis, Design and Implementation of a Motion Control Architecture for WormPicker 2.0 Robotic System (The Ohio State University, Knowledge Bank handle 1811/105762).

WormPicker 2.0 is a layered, task‑centric robotics platform that automates plate‑based worm manipulation at 13 animals min⁻¹—a four‑fold improvement over prior systems—while maintaining sub‑0.01 mm positioning accuracy. It marries a Yaskawa GP4 industrial manipulator with ROS 2, MoveIt 2, and a purpose‑built motion‑control stack to eliminate the manual bottleneck in high‑throughput C. elegans genetics.

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Table of Contents

1. Overview
2. Key Features
3. Performance Highlights
4. System Requirements
5. Repository Structure
6. Installation
7. Usage
8. Citing WormPicker 2.0
9. Contribution Policy
10. License
11. Contact

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Overview

WormPicker 2.0 translates high-level experimental commands into collision-free trajectories via a five-layer software architecture:

1. Interface Layer:
   • CLI & TCP/IP command APIs
2. Command Layer:
   • Lightweight parser-combinator library produces immutable CommandInfo objects
3. Task Layer:
   • Factory pattern expands commands into MoveIt Task Constructor (MTC) tasks composed of reusable motion stages
4. Planning Layer:
   • Planner factory selects OMPL / Pilz / Cartesian planners and validates solutions against heuristics
5. Execution Layer:
   • ROS 2 controllers stream trajectories to the GP4; feedback loops maintain gentle contact with agar

A semi-automated calibration node aligns digital models with the physical work-cell, ensuring repeatability across up to 250 plates.

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Key Features

Category	Highlights
Task-based architecture	Declarative chain-of-stage design built on ROS 2 + MoveIt Task Constructor
Rich motion primitives	Joint, Cartesian, circular, and relative moves with per-stage velocity / acceleration scaling
Workstation & hotel maps	JSON-defined reference frames for plates, tools, and storage locations

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Performance Highlights

• Throughput: 13 worms min⁻¹ (×4 vs. WormPicker 1.0)
• Repeatability: ± 0.01 mm (Yaskawa GP4 spec)
• Workspace: 250 standard 6 cm agar plates
• Runtime: 24/7 continuous operation

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System Requirements

Category	Requirement
Operating System	Ubuntu 22.04 LTS (tested)
ROS 2	Humble Hawksbill
MoveIt 2	Humble with Task Constructor
Compiler	GCC 11+ / Clang 15+ with C++20 support
CMake	3.22 or newer
Robot Hardware	Yaskawa GP4 or any ROS 2-compatible 6+ DOF arm
Dependencies	Boost, fmt, yaml-cpp, nlohmann/json, tf2, Eigen3

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Repository Structure

worm-picker/
├── worm_picker_core/              # Core libraries & nodes
│   ├── include/worm_picker_core/  # Public headers (core | infra | system | utils)
│   ├── src/                       # Implementation
│   └── config/                    # YAML params + launch files
├── worm_picker_custom_msgs/       # ROS 2 msg/srv definitions
├── worm_picker_description/       # URDF, meshes, semantic description
├── worm_picker_moveit_config/     # MoveIt 2 configuration package
├── dependencies.repos             # wstool / vcs import file
├── CONTRIBUTING.md                # Restricted contribution policy
├── LICENSE                        # Custom Limited License Agreement
└── README.md                      # This document

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Installation

TO BE FILLED OUT LATER

Quick reference
Clone with vcs import < dependencies.repos · colcon build --symlink-install · source the workspace · launch worm_picker_system.launch.py.

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Usage

TO BE FILLED OUT LATER

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Citing WormPicker 2.0

If this software contributes to your academic work, please cite the associated thesis:

Kaising, L. (2025). Design and Implementation of a Motion Control Architecture for WormPicker 2.0 Robotic System. The Ohio State University. Department of Biomedical Engineering Honors Theses. https://kb.osu.edu/handle/1811/105762

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Contribution Policy

This repository is governed by a restricted licence. Contributions are accepted only from authorised Fang‑Yen‑Lab personnel. External pull requests will be closed without review. See CONTRIBUTING.md for details.

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License

WormPicker 2.0 is released under a bespoke Custom Limited License Agreement that grants defined rights exclusively to the Fang‑Yen‑Lab. Refer to the LICENSE file for legally binding terms.

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Contact

Role	Name	E‑mail
Original Author	Logan Kaising	[email protected]
Lab Manager	Li (John) Zihao	[email protected]

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© 2025 Logan Kaising. All rights reserved.