Sensorized Gripper Force Sensing via Crank Angle Detection
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Solution Overview
Problem
Conventional grippers, such as rigid and soft grippers, lack precise force sensing and feedback, making them unsuitable for high-precision operations, while sensorized grippers face issues with precise sensing due to complex electrical wirings and high costs associated with pressure sensors.
Innovation Solution
A smart sensorized gripper with a driving assembly, gripping assemblies, angle sensors, and a displacement sensor, which allows for precise sensing of axial and gripping forces along the Z and X directions, respectively, without the need for additional electrical wirings on the gripping elements, simplifying the structure and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure sensors are mounted at the gripping portions of the gripper to sense gripping force, then sensing function is achieved, but electrical wirings become complicated and cost increases
Solution Approach 1:
The patent extracts the sensing function from the gripping portions and relocates it to the driving assembly. The angle sensors and displacement sensor are installed in the driving assembly to detect the motion state of the driving element, which indirectly reflects the gripping force through mechanical coupling. This extraction eliminates the need for complex electrical wirings in the gripping portions while maintaining sensing capability.
Solution Approach 2:
The patent introduces the driving assembly as an intermediary between the control system and the gripping portions. The angle sensors and displacement sensor detect the motion state of the driving element, and this information is used to calculate the gripping force through mechanical coupling relationships. This intermediary approach avoids direct sensor mounting in the gripping portions, simplifying the electrical wiring structure.
2Strength
If rigid gripper is used for automated operations, then structural strength is maintained, but force feedback function is lost making high precision operations difficult
Solution Approach 1:
The patent implements feedback by installing angle sensors and displacement sensor in the driving assembly to detect the motion state of the driving element. This feedback information is used to calculate the gripping force and axial force, enabling force feedback control while maintaining the rigid gripper structure. The feedback mechanism allows the system to monitor and adjust gripping forces in real-time.
3Reliability
If soft gripper is used to avoid damage during collision, then flexibility and damage resistance are improved, but control precision of gripping force and position deteriorates
Solution Approach 1:
The patent uses feedback from angle sensors and displacement sensor to detect the motion state of the driving element, which indirectly reflects the gripping force and position. This feedback enables precise control of gripping force and position while maintaining the rigid gripper structure that provides necessary stiffness for positioning control.
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
The smart sensorized gripper enhances precision and reliability in force sensing, reduces production costs, and provides a soft gripping touch to prevent damage to objects and the gripper, while maintaining stiffness, thus improving its functionality and application scope.
Implementation Method 1
The gripping element has an elastic portion and a gripping portion, which is connected to the elastic portion
Implementation Method 2
Each one of the two angle sensors is configured to sense an angle of a respective one of the two crank elements of the corresponding gripping assembly
Implementation Method 3
The displacement sensor is mounted at the gripper base, is electrically connected to the controlling device, and is configured to sense a displacement of the moving element
Data Source
AI summary
A smart sensorized gripper connected to and controlled by a controlling device comprises a gripper base, a driving assembly, two moving assemblies, two gripping assemblies, two angle sensors and a displacement sensor. The driving assembly and the sensors are disposed on the gripper base and connected to the controlling device. The driving assembly drives the gripping assemblies to grip and release an object through the moving assemblies. An axial force along a Z-direction and a gripping force along an X-direction of the smart sensorized gripper are controlled by sensing crank elements of the gripping assemblies with the angle sensors and sensing a displacement of a moving element of the driving assembly with the displacement sensor, increasing functionality and positioning precision. The sensors are disposed at the gripper base to avoid extra electrical wirings on the gripping assemblies, simplifying the wirings and reducing the cost.