Robot Gripper Center of Gravity Detection Using Force Sensors
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Solution Overview
Problem
Robot grippers face challenges in maintaining stability when gripping heavy or long articles, as they often slip or drop due to uncertainty about the center of gravity, leading to potential accidents in industrial settings.
Innovation Solution
A robot gripper with semispherical upper and lower contact parts equipped with sensor units to measure forces and a control unit that calculates the center of gravity's position, friction forces, and vertical/horizontal components to determine stability and adjust contact points for secure gripping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If robot grippers use conventional gripping methods without center of gravity detection, then the structure is simple, but the stability when gripping heavy or long articles deteriorates
Solution Approach 1:
The system performs preliminary detection of the article's center of gravity position and dimensions before executing the gripping action. The control unit calculates the center of gravity based on sensor measurements taken during the approach phase, then adjusts contact point positions accordingly to ensure stable gripping from the outset.
Solution Approach 2:
The sensor units provide real-time feedback on forces applied to contact parts, allowing the control unit to continuously monitor and adjust the gripping force distribution. This feedback mechanism enables dynamic adjustment of contact point positions and forces to maintain stability when the article's center of gravity is unknown or shifts during gripping.
2Reliability
If robot grippers add sensor units and control algorithms to detect center of gravity, then the stability improves, but the device complexity increases
Solution Approach 1:
The sensor units serve multiple functions: they detect forces at contact points, calculate the article's center of gravity position, determine article dimensions, and provide data for both gripping and lifting operations. This multi-functionality reduces the need for separate detection systems, thereby limiting the increase in device complexity while improving reliability.
Solution Approach 2:
The system uses the gripping contact parts themselves as measurement points for detecting the article's properties. The sensor units mounted on the contact parts directly measure forces during normal gripping operations, eliminating the need for separate measurement devices. The control unit then uses this self-generated data to calculate center of gravity and adjust gripping parameters.
3Measurement precision
If robot grippers assume the center of gravity is at the center position, then the control is simple, but the accuracy of stability determination deteriorates for unknown objects
Solution Approach 1:
The system replaces complex mechanical center of gravity detection mechanisms with a computational approach. The control unit calculates the center of gravity position by processing force measurements from sensor units using mathematical relationships, substituting physical measurement complexity with computational algorithms that can be implemented in software.
Solution Approach 2:
The system determines the center of gravity position by analyzing force distributions across multiple contact points in different spatial dimensions. By measuring forces at upper and lower contact parts and using vertical and horizontal distance relationships, the control unit calculates the center of gravity coordinates through multi-dimensional force analysis, achieving precise detection without direct mechanical measurement.
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 stable gripping of unknown objects by calculating the center of gravity's position and adjusting contact points, ensuring the article remains centered between the arms, thereby preventing slipping and dropping, and allowing for secure lifting of heavy or long articles.
Implementation Method 1
Sensor units mounted on the upper contact parts and the lower contact parts measure vertical or horizontal forces applied to the upper contact parts or the lower contact parts when gripping the article
Implementation Method 2
A control unit configured to determine whether the center of gravity of the article is located at a center position between the ends of the arms using vertical and horizontal distances between the ends of the arms and vertical components of the forces measured by the sensor units
Data Source
AI summary
A robot gripper is provided comprising two robot arms, upper contact parts, and lower contact parts disposed at the ends of each of the two robot arms. The upper and lower contact parts are in contact with a top and a bottom of an article when gripping the article, The upper and lower contact parts are semispherical shaped and have predetermined radii. Sensor units are mounted on the upper contact parts and the lower contact parts. The sensor units measure vertical or horizontal forces applied to the upper contact parts or the lower contact parts when gripping the article. A control unit configured to determine whether the center of gravity of the article is located at a center position between the ends of the arms using vertical and horizontal distances between the ends of the arms and vertical components of the forces measured by the sensor units when gripping the article is provided.