Multi-Finger Gripping with 3D Occlusion Interpolation
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Solution Overview
Problem
Existing gripping methods using multi-fingered hands face challenges in deriving gripping positions and postures for workpieces with areas where three-dimensional measurement data cannot be obtained due to occlusion or surface characteristics, leading to incomplete data and inability to grip such workpieces effectively.
Innovation Solution
A method that uses a three-dimensional measurement sensor to obtain range information, interpolates unmeasured areas using closer or farther distances from adjacent measured areas, and adjusts finger distance and position to enable gripping of workpieces by classifying and interpolating unmeasured areas within the object's area, ensuring accurate and safe grasping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If three-dimensional measurement data is obtained using a stereo measurement method, then measurement precision is improved, but areas with occlusion or specific surface states cannot be measured, leading to incomplete data
Solution Approach 1:
The system performs preliminary classification of the measurement area into measured areas and unmeasured areas before attempting to derive gripping parameters. This preliminary action identifies regions with complete three-dimensional data and regions with occlusion or measurement failures, allowing the system to prepare appropriate handling strategies for each area before actual gripping operations.
Solution Approach 2:
The patent introduces an intermediary mechanism that handles the transition between measured and unmeasured areas. When unmeasured areas are detected, the system uses intermediate strategies such as avoiding these areas for gripping, using alternative measurement approaches, or applying default gripping parameters that are safe for unknown surface conditions, thus mediating between the incomplete data and the need for complete gripping information.
2Productivity
If gripping position and posture are derived based on available workpiece measurement data, then gripping efficiency is improved, but gripping cannot be performed for workpieces located near unmeasured areas
Solution Approach 1:
The patent segments the workpiece surface into measured areas and unmeasured areas, allowing different gripping strategies to be applied to each segment. For measured areas, efficient gripping parameters are derived using available three-dimensional data. For unmeasured areas, the system applies conservative default parameters or avoids these regions, ensuring that gripping reliability is maintained across the entire workpiece surface.
Solution Approach 2:
The system performs partial action by deriving gripping parameters only for measured areas where sufficient three-dimensional data is available, while applying default or avoided strategies for unmeasured areas. This partial approach ensures that gripping operations can proceed efficiently for accessible regions without compromising the overall reliability of the gripping system when encountering unmeasured regions.
3Adaptability or versatility
If the predetermined area is classified into measured area and unmeasured area, then handling of incomplete data is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by treating measured areas and unmeasured areas with different processing qualities and strategies. Measured areas receive full processing for accurate gripping parameter derivation, while unmeasured areas receive simplified processing using default parameters or avoidance strategies. This local differentiation improves adaptability to incomplete data while minimizing overall processing complexity by not applying complex processing uniformly across all areas.
Data Source
AI summary
A gripping method relates to a gripping method for gripping an object using a multi-fingered hand provided with a plurality of fingers. A three-dimensional measurement sensor is used to measure an area that contains the object to obtain three-dimensional information. If the area includes an area for which no three-dimensional information can be obtained, the area is separated and is interpolated using the range information indicating the closer one of distances obtained at two positions on an axis extending along a direction in which the fingers are opened and closed, the two positions being adjacent to the unmeasured area with the unmeasured area interposed therebetween. Then, the distance between the fingers for gripping the object is decided, and the multi-fingered hand is controlled based on the distance.