Grip Tool Slip Detection Using Load Distribution Sensing
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Solution Overview
Problem
Existing grip tools, such as forceps and robot hands, struggle to detect slips on slippery objects, particularly in low-friction environments like human organs covered with lubricants, making it difficult to maintain a secure grip.
Innovation Solution
A grip system equipped with a grip tool featuring a pair of grip portions and a sensor unit with multiple force sensors measuring triaxial forces, allowing detection of slips based on load distribution, center or peak position changes, and friction coefficient measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If friction-based slip detection is used, then slip detection capability is improved, but detection reliability deteriorates on low-friction surfaces
Solution Approach 1:
The patent replaces friction-based mechanical detection with a magnetic field-based detection system. A magnet is attached to the distal end of the forceps, and a magnetic sensor detects the magnetic field strength. When the forceps grip the object, the magnet moves with the object, causing changes in magnetic field strength that indicate gripping state and slip conditions, eliminating dependence on friction.
Solution Approach 2:
The patent introduces a magnet as an intermediary element attached to the forceps and a magnetic sensor as an intermediary detection device. The magnet serves as a mediator that translates mechanical gripping motion into detectable magnetic field changes, while the magnetic sensor acts as an intermediary that converts magnetic field variations into electrical signals for slip detection.
2Measurement precision
If multiple force sensors are added to detect load distribution, then slip detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent extracts the detection function from complex multi-sensor systems and concentrates it in a single magnetic sensor. By removing the need for multiple force sensors and their associated signal processing circuits, the system achieves slip detection accuracy through a simplified single-sensor magnetic field measurement approach.
Solution Approach 2:
The magnetic sensor system performs multiple functions: detecting gripping state, detecting slip conditions, and determining object position, all through a single sensor that measures magnetic field strength variations. This multi-functional capability replaces what would traditionally require multiple specialized sensors.
3Reliability
If friction coefficient measurement is implemented, then slip prediction capability is improved, but measurement difficulty increases on slippery surfaces
Solution Approach 1:
The patent substitutes direct friction coefficient measurement with magnetic field-based slip prediction. Instead of measuring friction forces directly on the slippery surface, the system predicts slip by monitoring changes in magnetic field strength that correspond to relative motion between the forceps and the object, bypassing the difficulty of direct friction 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 accurate detection and prevention of slips on slippery objects by evaluating slipperiness and predicting the start of slipping, ensuring the object is maintained without slipping.
Implementation Method 1
a magnetic sensor that detects a magnetic field generated by the magnet
Data Source
AI summary
Provided is a grip tool that allows detecting a slip of an object. The grip tool includes a pair of grip portions that sandwiches to grip an object; an opening/closing mechanism that opens and closes the pair of grip portions; and at least one sensor unit disposed in one or both of the pair of grip portions. The sensor unit includes a plurality of force sensors disposed in a predetermined distribution. The plurality of force sensors each have a function of measuring forces in triaxial directions received from the object. The sensor unit can measure a load distribution received from the object. The slip of the object is detectable based on the load distribution.