3D Workpiece Retrieval Using Virtual Grip Positioning
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Solution Overview
Problem
Existing workpiece pick-up systems struggle to reliably grasp workpieces with angled postures, as they can only measure surface information visible from a specific sensor position, leading to potential misalignment and inefficient pick-up processes.
Innovation Solution
A workpiece pick-up system that includes a three-dimensional measuring instrument, a robot with a gripping hand, and a control device. The control device uses stored workpiece and hand models to identify the workpiece's position and posture, and determines the optimal gripping position and posture through virtual simulation, ensuring accurate grasping regardless of the workpiece's orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If three-dimensional measurement is performed from a specific sensor position, then surface shape information can be acquired, but only information on visible surfaces is obtained leading to incomplete workpiece data
Solution Approach 1:
The patent transitions from two-dimensional sensor viewing to three-dimensional virtual space modeling. By constructing a complete 3D workpiece model in virtual space that includes all surfaces (visible and invisible), the system compensates for the sensor's limited viewing angle and captures complete geometric information for accurate grip determination.
Solution Approach 2:
The patent creates a virtual copy (digital model) of the workpiece in virtual space that replicates the physical workpiece's complete geometry. This virtual model allows the system to analyze and determine grip positions without being constrained by the sensor's limited physical viewing angle, effectively capturing information that would otherwise be invisible.
2Device complexity
If workpiece pickup is performed without virtual model positioning, then the process is simpler, but accurate grip position determination for angled workpieces cannot be achieved
Solution Approach 1:
The patent performs preliminary positioning of the workpiece model in virtual space before determining the grip position. By pre-establishing the workpiece's position and posture in the virtual environment through model positioning, the system can accurately calculate the optimal grip position for angled workpieces without requiring complex real-time adjustments during the pickup operation.
3Reliability
If workpieces are picked up one by one from random overlapping arrangements, then complete workpiece inventory is achieved, but the process time increases significantly
Solution Approach 1:
The patent performs preliminary three-dimensional measurement and virtual model positioning of all workpieces in the overlapping arrangement before the actual pickup operation. This pre-processing allows the system to plan and determine optimal grip positions for multiple workpieces in advance, enabling more efficient sequential pickup without repeated measurement and calculation cycles.
Solution Approach 2:
The patent introduces a virtual space model as an intermediary between the physical overlapping workpieces and the pickup execution. This virtual model allows the system to analyze the spatial relationships and determine pickup sequences and grip positions without physically manipulating workpieces during the planning phase, reducing overall process time.
4Device complexity
If grip position is determined without hand model positioning in virtual space, then the system is simpler, but appropriate grip posture for angled workpieces cannot be determined
Solution Approach 1:
The patent extends the modeling from simple 2D or basic 3D representation to comprehensive 3D virtual space positioning that includes both workpiece and hand models with full positional and postural information. This dimensional enhancement allows the system to determine appropriate grip postures for workpieces at various angles by visualizing and calculating the spatial relationship between the hand and workpiece in three-dimensional virtual space.
Data Source
AI summary
A workpiece retrieval system according to one embodiment of the present disclosure, which is capable of reliably retrieving a workpiece, comprises a three-dimensional measurement instrument that measures the shape of a workpiece, a robot having a hand that grips the workpiece, and a control device that controls the robot such that a workpiece is retrieved by the robot on the basis of a result of measurement by the three-dimensional measurement instrument, the control device having: a storage unit that stores a workpiece model, in which the three-dimensional shape of the workpiece is modeled, and a hand model, in which the three-dimensional shape of the hand is modeled; a matching unit that identifies the position and orientation of the workpiece according to a process for matching the result of measurement by the three-dimensional measurement instrument and the workpiece model; a model-positioning unit that positions the workpiece model, within a virtual space, at the position and orientation identified by the matching unit; and a grip determination unit that positions the hand model within the virtual space and, on the basis of the relationship between the hand model and the workpiece model that are positioned within the virtual space, determines a grip position and orientation that apply to the hand when the workpiece is gripped by the hand.