Robotic Gripper Torque Measurement via Torsion Spring Winding
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Solution Overview
Problem
Existing robotic gripping devices face challenges in efficiently measuring torque applied to their fingers without complex sensors or geometries, particularly when interacting with soft, fragile, or delicate objects, which requires accurate force information for precise handling.
Innovation Solution
A robotic gripping device design featuring two opposable fingers coupled to a rotating actuator with a torsion spring, where encoders detect the rotation of the actuator and fingers, allowing the determination of torque without specialized sensors, by winding up the torsion spring in response to reaction forces from the object.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If specialized torque sensors or complex sensor systems are used to measure torque applied to robotic fingers, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system uses the actuator's own motor and existing encoders to measure torque indirectly through the torsion spring mechanism, eliminating the need for separate torque sensors. The motor rotates the torsion spring in response to finger torque, and encoders detect this rotation, allowing the system to self-measure torque using components already present in the actuator assembly.
Solution Approach 2:
The torsion spring serves as an intermediary element between the finger torque and the motor rotation. Instead of directly measuring torque with a sensor, the system uses the torsion spring to convert torque into rotational movement of the motor shaft, which can then be measured by existing encoders. This intermediary mechanism enables indirect torque measurement without specialized sensors.
2Measurement precision
If complex sensor systems are implemented to detect force applied to fingers, then measurement precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The system leverages the actuator's existing motor and encoders to perform torque measurement, eliminating the need for separate sensor components. The motor itself becomes part of the measurement system by rotating the torsion spring in response to finger torque, and the encoders already present in the actuator detect this rotation, simplifying manufacturing by using existing components for dual purposes.
Solution Approach 2:
The motor and encoders serve multiple functions: they drive the actuator for finger movement and simultaneously function as the measurement system for torque detection. The torsion spring mechanism enables the same components to perform both actuation and sensing functions, reducing the total number of components needed and simplifying the manufacturing process.
3Measurement precision
If specialized torque sensors are used to measure reaction forces from objects, then measurement precision is improved, but productivity deteriorates due to system complexity
Solution Approach 1:
The actuator system performs torque measurement as a byproduct of its normal operation, using the motor and encoders already present in the system. This eliminates the need for additional specialized sensors that would increase complexity and reduce productivity. The system measures torque efficiently by utilizing its own operational components.
Solution Approach 2:
The torsion spring acts as a mechanical intermediary that converts the reaction force from the object into rotational movement of the motor shaft. This mechanical transduction enables the existing encoders to measure torque without requiring electronic torque sensors, maintaining system simplicity and productivity while achieving accurate force 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
This approach simplifies the measurement of torque applied to the fingers, providing accurate force information for control systems, enabling efficient and precise handling of various objects without the need for complex sensor systems, thus enhancing the robotic device's operational efficiency and versatility.
Implementation Method 1
a torsion spring surrounding the actuator, the torsion spring having a first end and a second end, wherein the first end is coupled to the motor of the actuator and the second end is coupled to a second finger of the two opposable fingers
Implementation Method 2
the actuator is further configured to, when the two opposable fingers are both in contact with the object and the object prevents the fingers from further movement toward each other, further rotate the shaft relative to the motor to wind up the torsion spring
Data Source
AI summary
A robotic gripping device is provided. The robotic gripping device includes two opposable fingers and an actuator having a motor and a shaft, wherein the shaft is coupled to a first finger. The robotic gripping device also includes a torsion spring surrounding the actuator, the torsion spring having first and second ends, wherein the first end is coupled to the motor of the actuator and the second end is coupled to a second finger. Further, the actuator is configured to rotate the shaft relative to the motor by a first amount to move the two opposable fingers toward each other to contact the object. The actuator is also configured to further rotate the shaft relative to the motor to wind up the torsion spring when the two opposable fingers are both in contact with the object and the object prevents the fingers from further movement toward each other.