Bulk Workpiece Picking with Adaptive 3D Measurement Parameters
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Solution Overview
Problem
Conventional bulk picking devices face challenges in accurately detecting workpieces due to environmental changes and surface condition variations, leading to a decrease in detection success rate as the picking operation progresses, especially when the number of workpieces decreases.
Innovation Solution
A workpiece picking device equipped with a sensor, hand, and control device that measures three-dimensional positions, calculates positions and orientations, and modifies measurement and calculation parameters based on detected situations to improve detection accuracy and success rate, including features like defective region extraction and parameter modification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If three-dimensional measurement is performed with fixed measurement parameters, then initial detection accuracy is maintained, but detection success rate decreases as picking operation progresses and workpiece number reduces
Solution Approach 1:
The measurement parameters are changed from fixed to dynamic, allowing automatic adjustment based on the current number of workpieces detected. The control device modifies measurement parameters adaptively as the picking operation progresses, ensuring reliable detection even when workpiece density changes.
Solution Approach 2:
The patent explicitly changes measurement parameters (such as measurement range, resolution, or scanning frequency) based on the detected situation, particularly when the number of workpieces decreases. This parameter adaptation resolves the contradiction by maintaining detection reliability under varying workpiece quantities.
2Reliability
If stable measured values are prioritized for picking, then initial picking success is achieved, but proportion of undetected workpieces increases over time
Solution Approach 1:
The control device continuously monitors the number of detected workpieces and uses this feedback to determine when to modify measurement parameters. This feedback loop ensures that as picking progresses and detection becomes more difficult, the system adapts to maintain comprehensive detection coverage.
Solution Approach 2:
The system performs preliminary assessment of detection quality by counting detected workpieces, and before proceeding with picking, determines whether parameter modification is needed. This preliminary detection quality assessment prevents missed measurements from occurring in the first place.
3Device complexity
If environmental changes and surface condition variations are not accounted for, then device complexity remains low, but detection reliability deteriorates
Solution Approach 1:
The measurement system performs self-adjustment by automatically detecting the number of workpieces and modifying its own measurement parameters without external intervention. This self-service capability maintains detection reliability under varying environmental conditions while avoiding the need for complex external control systems.
Data Source
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AI summary
The purpose of the invention is to improve the success rate of grasping a workpiece that has been loaded in bulk and to achieve good picking operations. A workpiece picking device comprises a sensor to measure a workpiece, a hand to grasp the workpiece, a robot to move the hand, and a control device for these. The control device has: a position/orientation calculation unit that calculates the workpiece position, orientation, and the like; a grasping orientation calculation unit that calculates the orientation for the hand to grasp the workpiece; a route calculation unit that calculates a route to move the hand into the grasping orientation; a sensor control unit that controls operation of the sensor; a hand control unit that controls operation of the hand; a robot control unit that controls operation of the robot; a state determination unit that determines the state of the workpiece on the basis of three-dimensional position measurement results or the like; and a parameter modification unit that modifies at least one of measurement parameter and various calculation parameters when the determination results for the workpiece state fulfill a prescribed condition.