Laser Speckle 3D Encoder for Robotic Arm Position Compensation
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Solution Overview
Problem
Conventional robotic arms face positioning errors due to manufacturing and assembly inaccuracies, leading to discrepancies between predictive and actual end-effector positioning, which current measurement techniques cannot effectively evaluate or correct.
Innovation Solution
A three-dimensional displacement measurement method using laser speckle images, where coherent light is emitted on surfaces of a robotic arm, and image sensors record speckle patterns to determine shift directions and distances, enabling absolute correction compensation for improving positioning precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement techniques are used to evaluate robotic arm positioning, then the system remains simple and easy to operate, but positioning precision and manufacturing precision deteriorate due to uncorrected errors from manufacturing and assembly inaccuracies
Solution Approach 1:
The patent introduces laser beams as intermediary elements that interact with the robotic arm surfaces to create speckle patterns. These patterns serve as mediators between the measurement system and the robotic arm, enabling precise positioning measurement without direct physical contact with the arm's mechanical components.
Solution Approach 2:
The patent replaces conventional mechanical measurement techniques with optical measurement methods. Instead of using mechanical probes or contact-based measurement devices, the system uses laser speckle imaging to non-contactingly measure positioning errors, thereby avoiding mechanical interference and wear.
2Manufacturing precision
If absolute correction compensation is implemented to improve end-effector positioning accuracy, then positioning precision improves, but device complexity increases due to the additional measurement and compensation system
Solution Approach 1:
The patent implements a feedback mechanism where the actual positioning of the end-effector is continuously measured using laser speckle imaging, compared with the predicted positioning from the control system, and the errors are compensated by adjusting the control commands. This closed-loop feedback ensures high positioning accuracy without requiring complex mechanical modifications.
Solution Approach 2:
The patent changes the measurement parameters from conventional mechanical dimensions to optical speckle pattern characteristics. By analyzing the spatial distribution and intensity variations of laser speckle patterns, the system extracts positioning information with high precision, transforming the measurement approach rather than increasing mechanical complexity.
3Measurement precision
If multiple surfaces of the robotic arm are measured using laser speckle imaging, then three-dimensional displacement measurement precision improves, but the measurement process complexity and time consumption increase
Solution Approach 1:
The patent uses periodic scanning of laser beams across multiple surfaces of the robotic arm. Instead of simultaneously measuring all surfaces (which would require complex multi-point illumination), the system sequentially illuminates and measures different surfaces in a periodic manner, reducing system complexity while maintaining three-dimensional measurement capability.
Solution Approach 2:
The patent measures three-dimensional displacement by combining two-dimensional speckle pattern measurements from different surfaces. By capturing speckle patterns from multiple angular perspectives and integrating the information, the system reconstructs three-dimensional positioning data, transforming 2D optical measurements into 3D spatial information.
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 method provides precise absolute positioning correction for robotic arms, enhancing their positioning accuracy by directly compensating for errors in the end-effector's positioning, thereby improving overall precision beyond conventional limits.
Implementation Method 1
A first laser beam is emitted toward a first surface of the robotic arm to generate a first laser speckle, and a second laser beam is emitted toward a second surface of the robotic arm that is perpendicular or adjacent to the first surface to generate a second laser speckle
Implementation Method 2
an image sensor records speckle patterns to determine shift directions and distances
Implementation Method 3
comparing the first laser speckle image with a third laser speckle image to determine a shift direction and a shift distance of the first surface and comparing the second laser speckle image with a fourth laser speckle image to determine a shift direction and a shift distance of the second surface
Data Source
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AI summary
A three-dimensional displacement measurement method of laser speckle images and application thereof, which integrate two light sources, two image sensors, a signal processing component to measure the movement behavior of two laser speckle image groups, and determine the relative displacement of a working object. By using the three-dimensional displacement measurement method of laser speckle images, an accurate three-dimensional relative displacement is obtained, and then applied to a robotic arm positioning error compensation device.