Optoelectronic Soft Tactile Sensor for Incipient Slip Detection
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Solution Overview
Problem
Robotic grippers lack the tactile sensitivity to detect incipient slipping, which is crucial for precise gripping and manipulation of objects, as they cannot replicate the human ability to sense the grip status and impending slip in real-time.
Innovation Solution
An optoelectronic tactile sensor with a deformable body and optical waveguides is integrated into the gripper, which detects lateral deflections and changes in gap sizes to accurately sense stick-slip conditions, enabling real-time detection and corrective actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional tactile sensors are used in robotic grippers, then the gripper can detect basic contact forces, but it cannot detect incipient slipping conditions in real-time with human-like sensitivity
Solution Approach 1:
The patent replaces traditional mechanical tactile sensors with an optoelectronic sensing system. Optical waveguides (fiber optic cables) are embedded in the deformable body, and light transmission through these waveguides changes when the body deforms during gripping. This optical substitution enables detection of incipient slipping conditions with human-like sensitivity while avoiding the complexity and limitations of mechanical sensor arrays.
Solution Approach 2:
The patent uses a deformable body made of soft, flexible material that can conform to the gripper's gripping surface. This flexible shell deforms naturally when contact forces change during gripping, causing corresponding changes in the optical waveguide paths. The flexibility allows the sensor to detect subtle deformations associated with incipient slipping while maintaining structural simplicity.
2Ease of manufacture
If the sensor structure is simplified to reduce complexity, then manufacturing becomes easier, but the ability to detect subtle lateral deflections and incipient slip conditions deteriorates
Solution Approach 1:
By replacing complex mechanical sensor structures with optical waveguides embedded in a simple deformable body, the patent achieves both ease of manufacture and high measurement precision. The optical system detects subtle lateral deflections through changes in light transmission, maintaining deflection detection accuracy while simplifying the overall sensor structure and fabrication process.
Solution Approach 2:
The patent introduces optical waveguides as intermediary elements between the deformable body and the detection system. These waveguides act as mediators that translate mechanical deformations of the soft body into optical signal changes, enabling precise deflection detection without requiring complex mechanical sensor structures. This intermediary approach simplifies manufacturing while preserving measurement precision.
3Adaptability or versatility
If the deformable body is made softer to improve compliance with objects, then the structural stability and precision of optical waveguide positioning deteriorates
Solution Approach 1:
The patent employs a flexible deformable body that provides compliance with gripped objects while maintaining sufficient structural integrity. The soft material allows the body to conform to object shapes and absorb variations in contact forces, improving adaptability. Meanwhile, the optical waveguides are positioned and secured within this flexible body to maintain stable optical paths despite the softness, achieving both compliance and positioning stability.
Solution Approach 2:
By using optical waveguides instead of rigid mechanical components, the patent achieves both soft compliance and stable positioning. The optical system is insensitive to the softness of the deformable body, allowing the body to be sufficiently soft for compliance while maintaining stable waveguide positioning for precise measurements.
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 sensor effectively prevents slipping by accurately detecting incipient slip conditions and allowing the gripper to take corrective actions, enhancing the robotic gripper's ability to maintain a stable grasp during manipulation.
Implementation Method 1
there may be one or more optical waveguides positioned within the deformable body
Implementation Method 2
produce a corresponding change in the gap of the one or more optical waveguides responsive to the lateral deflection
Data Source
AI summary
An opto-electronic sensor includes a deformable body that has a gripping surface, securable to and movable by a gripper to a position at which the gripper surface contacts an object, and includes optical waveguides positioned within the deformable body, each optical waveguide including a gap. The deformable body is configured to exhibit a lateral deflection responsive to receiving via the gripping surface a lateral force from the object. The deformable body and the one or more optical waveguides are mutually configured to produce a corresponding change in the gap of the one or more optical waveguides responsive to the lateral deflection. The change in the gap is detectable as a change in a light intensity, by a light source and a light detector. The lateral force is computed using the detected change.