Robot Gripping Force Upper Limit Setting via Iterative Pressing
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Solution Overview
Problem
Existing robot systems face challenges in accurately setting a target force upper limit to prevent sliding when gripping objects with unknown weights, requiring expensive measurement devices and complex control systems.
Innovation Solution
A method and system that use a force sensor and control unit to iteratively adjust and set a target force upper limit by repeatedly pressing an object against a contact surface, acquiring the pressing force, and adjusting the target force until a state where the pressing force is equal to or greater than the target force is achieved, thereby determining the upper limit for stable gripping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If expensive measurement devices (component analyzer, shape measurement sensor) are used to measure object material and three-dimensional shape for calculating gripping force, then gripping force specification accuracy is improved, but system cost increases
Solution Approach 1:
The patent extracts the essential measurement function from expensive specialized devices (component analyzer, shape measurement sensor) and replaces it with a simple force sensor that directly measures the pressing force. This eliminates the need for complex material analysis and 3D shape measurement while achieving the same goal of determining appropriate gripping force through direct force measurement during pressing operation.
Solution Approach 2:
The patent replaces expensive, complex measurement devices with a simple, inexpensive force sensor. The force sensor provides direct measurement of pressing force without requiring complex analysis systems, effectively using a cheap substitute that achieves the measurement objective without the high cost of specialized equipment.
2Measurement precision
If complex measurement devices and calculation methods are used to determine gripping force from object properties, then gripping force accuracy is improved, but control system complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the force sensor continuously monitors the pressing force during pressing operations. The control unit compares the measured pressing force with the target force and adjusts the gripping force accordingly. This closed-loop feedback system simplifies control by using direct force measurement feedback rather than complex open-loop calculations based on object properties.
Solution Approach 2:
The system performs self-adjustment of gripping force through the feedback loop. The force sensor automatically provides measurement data, and the control unit automatically adjusts the gripping force based on the comparison between measured and target forces, eliminating the need for complex external calculation systems or manual intervention.
3Reliability
If target force is increased to prevent sliding, then gripping reliability is improved, but object damage risk increases
Solution Approach 1:
The patent makes the target force dynamic rather than fixed. The control unit adjusts the target force based on real-time feedback from the force sensor during pressing operations. This allows the system to optimize gripping force for each specific situation, increasing reliability when needed while minimizing damage risk when lower forces suffice.
Solution Approach 2:
The patent changes the target force parameter dynamically based on measured pressing force. By adjusting the target force parameter in real-time according to actual conditions, the system achieves reliable gripping only when necessary while avoiding excessive force that could damage the object, thus resolving the contradiction between reliability and damage risk.
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
This approach allows for accurate and cost-effective setting of the target force upper limit, reducing the likelihood of sliding and enhancing the efficiency and accuracy of robotic operations without the need for expensive measurement devices.
Implementation Method 1
a force sensor detecting a force acting on the gripping unit
Data Source
AI summary
A method of setting a target force upper limit for a robot gripping an object with a gripping unit and operating by force control to bring an acting force close to a target force, includes gripping the object with the gripping unit, performing a pressing operation to press the object gripped by the gripping unit against a contact surface by the force control, performing a pressing force acquisition operation to acquire the force acting on the gripping unit during the pressing operation as a pressing force, repeating a setting change operation to increase the target force, the pressing operation, and the pressing force acquisition operation until a state in which the pressing force is not equal to or larger than the target force appears, and setting a target force upper limit based on the pressing force acquired in the pressing force acquisition operation at a time when the state appears.