Robot Arm Liquid Interface Detection for Pipetting Precision

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Solution Overview

Problem

Conventional robot systems in the biomedical field face challenges in achieving high accuracy and reproducibility during bench work operations, such as pipetting, due to the lack of precise detection of liquid interface levels, leading to inconsistent liquid suction and potential mixing of precipitates.

Innovation Solution

A robot system equipped with a sensor and an arm that includes a holding mechanism, where the sensor detects the liquid interface level, and an instructor controls the arm to ensure accurate pipetting by adjusting the liquid interface level during operations, using a detection unit with a light emitting and sensing part to determine the liquid level and adjust the pipetting process accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional robot systems perform bench work operations without precise liquid interface detection, then the system structure remains simple, but the manufacturing precision and reliability of liquid handling operations deteriorate

Engineering Contradiction:
Improveliquid handling precisionVSAvoidsystem structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

A sensor is introduced as an intermediary component between the robot arm and the liquid container. The sensor detects the liquid interface level and provides feedback signals to the control unit, which then adjusts the arm's positioning. This intermediary detection mechanism enables precise liquid handling without requiring complex mechanical modifications to the robot arm itself.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system implements a feedback loop where the sensor continuously monitors the liquid interface level, compares it with the target position, and the control unit adjusts the arm's movement based on this feedback. This closed-loop control ensures high precision in liquid handling operations while maintaining relatively simple system architecture.

Inventive Principle:
Principle #23Feedback

2Reliability

If the robot system uses basic positioning without liquid interface detection, then the device complexity remains low, but the reliability of liquid suction operations deteriorates due to inconsistent liquid levels

Engineering Contradiction:
Improveliquid suction reliabilityVSAvoiddetection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sensor provides real-time feedback on the liquid interface level, allowing the control unit to dynamically adjust the arm's positioning and suction depth. This feedback mechanism ensures consistent and reliable liquid suction operations even when liquid levels vary, without requiring overly complex detection systems.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system replaces complex mechanical positioning mechanisms with a simpler sensor-based detection and control system. Instead of using elaborate mechanical stops or guides to maintain consistent suction depth, the patent uses optical or other non-contact sensors to detect liquid levels and electronically control the arm's movement, reducing mechanical complexity while improving reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If the robot system performs pipetting operations without real-time liquid level detection, then the operation process remains simple, but the manufacturing precision of liquid transfer deteriorates due to incomplete suction or precipitate mixing

Engineering Contradiction:
Improveliquid transfer precisionVSAvoidoperation process simplicity
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The sensor continuously monitors the liquid interface level during pipetting operations and provides feedback to the control unit. This enables real-time adjustment of the suction depth and speed, ensuring complete liquid transfer without disturbing precipitates or causing splashing, while keeping the operation process straightforward and automated.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the arm's movement speed, suction depth, and pipetting parameters based on real-time liquid level detection. This dynamic adaptation allows the robot to optimize each pipetting operation for the specific liquid conditions, achieving high precision without complicating the overall operation process through manual intervention.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system enables high accuracy and reproducibility in bench work operations by precisely detecting and maintaining the liquid interface level, preventing incomplete suction or mixing of precipitates, thus enhancing the reliability of liquid handling tasks.

Implementation Method 1

a detection unit (21) including a light emitting part (21ba) and a light sensing part (21bb)

Methodology Applied
Scientific EffectLight transmission: Light

Implementation Method 2

detect an interface of a liquid... using a detection unit with a light emitting and sensing part

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP2875912B1Robot system, method for inspection, and method for producing inspection object
Publication Date: 2020.05.27 YASKAWA DENKI KK
  • EP2875912B1 patent drawingFigure 1A~1B
  • EP2875912B1 patent drawingFigure 2
  • EP2875912B1 patent drawingFigure 3A~3B

AI summary

A robot system (1) according to an embodiment includes a sensor (21b), an arm (13), and an instructor (31a). The sensor (21b) is configured to detect an interface of a liquid. The arm (13) includes a holding mechanism that holds a container containing the liquid. The instructor (31a) instructs the arm (13) to cause the container to enter a sensing region of the sensor (21b) while holding the container, so as to cause the sensor (21b) to detect the interface.