Linkage Gripper Force Sensing for Multi-DOF Fingertip Feedback
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Solution Overview
Problem
Existing gripping devices in robotics face challenges in accurately measuring multi-degree of freedom (DOF) force feedback, especially when handling fragile objects, as conventional methods like tactile sensors provide unreliable data and motor current monitoring is susceptible to noise.
Innovation Solution
The proposed solution involves a gripping device with linkage assemblies and load cells that measure axial forces in static equilibrium, allowing for the computation of force information output by the fingertip using force and moment equilibrium principles, enabling accurate monitoring of multi-DOF force applied by the gripping device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If tactile sensors are used to measure force feedback, then force measurement capability is provided, but measurement precision deteriorates due to unreliable data
Solution Approach 1:
The patent replaces tactile sensors with a mechanics-based force calculation system. By measuring axial forces in links using load cells and applying static equilibrium principles, the system computes fingertip forces without relying on direct tactile sensing, thereby improving both measurement precision and data reliability.
Solution Approach 2:
The patent introduces load cells as intermediary measurement devices that measure axial forces in the links rather than directly measuring fingertip forces. This indirect measurement approach through intermediaries (links and load cells) provides more reliable and precise force data compared to direct tactile sensing.
2Measurement precision
If motor current monitoring is used to infer force, then force information is obtained, but measurement precision deteriorates due to noise susceptibility
Solution Approach 1:
The patent replaces electrical current monitoring with a mechanical force measurement system using load cells. This substitution eliminates the noise susceptibility inherent in electrical measurements while providing direct mechanical force data through axial force measurements in the links.
3Measurement precision
If load cells are installed in multiple links, then force measurement capability is improved, but device complexity increases
Solution Approach 1:
The patent divides the force measurement function across multiple segments (links) of the gripping device. By installing load cells in different links (first link, second link, third link, or driving assembly), the system obtains multiple axial force measurements that can be combined through static equilibrium calculations to determine comprehensive fingertip force information.
4Measurement precision
If static equilibrium model is used to compute fingertip forces, then measurement precision is improved, but calculation complexity increases
Solution Approach 1:
The patent employs static equilibrium principles that leverage the inherent mechanical structure and force relationships of the gripping device itself. The system uses the device's own structural parameters (link lengths, connection points) and measured axial forces to self-determine fingertip forces through equilibrium equations, providing accurate computation without requiring external complex modeling.
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 enables precise computation of normal and tangential forces, as well as bending moments applied by the fingertip, enhancing the gripping device's ability to maintain stable and accurate force on objects, thereby improving its robustness and adaptability for complex grasping tasks.
Implementation Method 1
Each of the plurality of load cells is disposed in a respective one of at least three of the first link, the second link, the third link and the driving assembly, and is configured to measure an axial force of the respective one of at least three of the first link, the second link, the third link and the driving assembly
Data Source
AI summary
A gripping device, a robot and a method for sensing force information. The device includes a case, linkage gripping assemblies mutually matched to grip an object, a driving assembly and a plurality of load cells. Each linkage gripping assembly includes a fingertip, a first link fixedly connected to the fingertip, a second link including a first end rotatably connected to a first end of the first link and a second end rotatably connected to the case, and a third link including a first end rotatably connected to a second end of the first link and a second end rotatably connected to the case. The driving assembly is in transmission connection with the second end of the second link to rotate the second link. Each load cell is disposed in a respective one of at least three of the first link, the second link, the third link and the driving assembly.