Dynamic Mass Measurement Using Force and Acceleration Sensors
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Solution Overview
Problem
Conventional mass measurement devices struggle to accurately measure the mass of an article when it is being moved, particularly when attached to a manipulator or robot hand, due to displacement issues caused by gravity and movement-related errors.
Innovation Solution
A mass measurement device comprising a holding mechanism, a movement mechanism, a force measurement unit, and an acceleration measurement unit, which calculates the mass of the article by dividing the force by acceleration, allowing for accurate measurement even during movement and eliminating the need for regional gravity corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a load cell is used to measure mass in a stationary state, then measurement precision is improved by excluding acceleration effects, but the device cannot measure mass when the article is being moved
Solution Approach 1:
The invention transitions from a static measurement system to a dynamic one by actively moving the holding mechanism during measurement. The control unit executes a measurement program that imparts acceleration to the article, enabling mass measurement during movement rather than requiring a stationary state
Solution Approach 2:
The system changes the acceleration parameter from zero (stationary) to a controlled non-zero value during measurement. By intentionally varying the acceleration state and using force measurement unit data combined with acceleration measurement unit data, the system calculates mass dynamically using Newton's second law (F=ma)
2Adaptability or versatility
If a load cell is attached to a manipulator or robot hand for measuring moving articles, then adaptability is improved, but measurement precision deteriorates due to displacement and movement-related errors
Solution Approach 1:
The invention introduces an acceleration measurement unit as an intermediary device that measures the actual acceleration experienced by the article. This intermediary measurement allows the system to compensate for movement effects by using the acceleration data in conjunction with force data to calculate mass, thereby maintaining precision despite robot hand displacement
Solution Approach 2:
The system uses feedback from both the force measurement unit and the acceleration measurement unit to continuously monitor and calculate mass during movement. The control unit processes real-time data from both sensors, adjusting calculations based on actual measured acceleration values to maintain measurement accuracy
3Measurement precision
If conventional mass measurement devices are used, then additional devices like weight checkers and sorting devices are needed, but device complexity increases
Solution Approach 1:
The invention merges the mass measurement function directly into the robot hand system by integrating both a force measurement unit and an acceleration measurement unit into the holding mechanism. This combination eliminates the need for separate weight checkers and sorting devices, as the robot hand itself performs mass measurement during its normal operation
Solution Approach 2:
The robot hand system is given multiple functions: it not only holds and moves articles but also simultaneously measures their mass. The force measurement unit and acceleration measurement unit enable the same robotic system to perform both manipulation and measurement tasks, reducing the need for additional dedicated measurement equipment
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
Enables precise mass measurement of articles being moved, reducing the need for additional devices like weight checkers and sorting devices, and allows for integration with robots for concurrent inspection and sorting, while minimizing the impact of gravitational effects.
Implementation Method 1
the mass measurement device is provided with a holding mechanism configured to hold the article; a movement mechanism configured to move the holding mechanism; a force measurement unit provided between the holding mechanism and the movement mechanism and adapted to measure a force acting on the article during movement
Implementation Method 2
an acceleration measurement unit configured to measure acceleration acting on the article during movement
Data Source
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AI summary
Provided is a mass measurement device capable of measuring the mass of an article, even when the article is being moved. A mass measurement device (100) comprises a robot hand (23), a robot arm (11), a force sensor (21), an acceleration sensor (22), and a control unit (40). The robot hand (23) holds an article (Q). The robot arm (11) moves the robot hand (23). The force sensor (21) is provided between the robot hand (23) and the robot arm (11) and measures force acting on the article (Q) during movement. The acceleration sensor (22) measures acceleration acting on the article (Q) during the movement. The control unit (40) runs and controls the robot hand (23) and the robot arm (11), and calculates the mass of the article (Q) on the basis of the force and acceleration acting on the article (Q) during the movement.