3D Robot Picking Verification for Bulk Workpiece Removal
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Solution Overview
Problem
Existing robot systems face inefficiencies when removing workpieces loaded in bulk, as they often fail to grip the correct workpiece or require additional devices for state verification, leading to longer cycle times and potential misorientation issues.
Innovation Solution
A robot system equipped with a hand that can grip workpieces without setting orientation, combined with a three-dimensional sensor for position and orientation detection, and a controller that uses model matching to select and verify the target workpiece through comparison of captured images before and after lifting, ensuring accurate gripping and conveying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hand with multiple craws is used to grip workpieces, then the gripping capability on certain parts is improved, but the ability to grip workpieces in various orientations deteriorates
Solution Approach 1:
Instead of using a hand with multiple craws that attempts to adapt to various orientations, the invention inverts the approach by using a simple gripper that maintains a fixed orientation while the robot arm adjusts its position and orientation to present the gripper optimally to each workpiece. This resolves the contradiction by making the gripper simple and fixed while achieving versatility through the robot's degrees of freedom.
Solution Approach 2:
The invention applies dynamics by making the robot arm's position and orientation adjustable and adaptable, while the gripper itself remains simple and fixed. The dynamic adjustment of the robot arm allows the system to handle workpieces in various orientations without requiring a complex multi-craw gripper, thus achieving both reliability and adaptability.
2Reliability
If a device that detects change in mass is provided to check gripping state, then the verification of workpiece gripping is improved, but the device complexity increases
Solution Approach 1:
The invention applies self-service by using the robot arm's own motion sensors and control system to detect whether a workpiece has been successfully gripped. Instead of adding external mass detection devices, the system uses the robot's existing capabilities to monitor changes in its own motion characteristics when gripping occurs, thereby verifying the gripping state without increasing device complexity.
Solution Approach 2:
The invention uses the robot arm's motion control system as an intermediary to detect gripping state. Rather than directly measuring mass change with external sensors, the motion control system indirectly detects gripping by monitoring changes in acceleration, velocity, or position feedback when the workpiece is grasped, thus avoiding additional complex detection devices.
3Measurement precision
If a photoelectric sensor is attached to the hand to detect gripping state, then the verification accuracy is improved, but the device complexity and cost increase
Solution Approach 1:
The invention uses the robot system's own motion feedback mechanisms to detect gripping state without adding external photoelectric sensors. The motion control system monitors changes in the robot arm's dynamics when gripping occurs, providing sufficient verification accuracy using existing system capabilities rather than additional expensive sensors.
Solution Approach 2:
The invention replaces optical detection methods (photoelectric sensors) with mechanical/dynamic detection methods. By monitoring changes in the robot arm's motion characteristics, acceleration, or position feedback when gripping occurs, the system achieves gripping verification through mechanical means rather than adding complex optical sensing devices.
4Reliability
If the robot stops to verify gripping state before conveying, then the accuracy of workpiece selection is improved, but the cycle time increases
Solution Approach 1:
The invention implements continuous feedback during the robot's motion to verify gripping state in real-time, rather than stopping to check. The motion control system monitors gripping status throughout the conveyance process, allowing the robot to maintain motion while verifying workpiece selection accuracy, thus reducing cycle time without sacrificing reliability.
Solution Approach 2:
The invention maintains continuous motion of the robot arm while performing verification of the gripping state. Instead of interrupting the conveyance process with a stop, the system continuously monitors gripping status during motion, ensuring workpiece selection accuracy is verified without breaking the continuous useful action of conveying, thereby reducing cycle time.
Data Source
AI summary
A controller includes a generation unit that generates three-dimensional information, a deletion unit that deletes information about at least part of the measurement points in the three-dimensional information, and a determination unit that determines a state where the robot grips a workpiece. The generation unit generates first three-dimensional information before the robot implements an operation of gripping a target workpiece. The generation unit generates second three-dimensional information after the robot has implemented an operation of lifting the target workpiece. The deletion unit generates third three-dimensional information in which information about measurement points in the second three-dimensional information is deleted from the first three-dimensional information. The determination unit determines whether or not the workpiece in the third three-dimensional information matches the target workpiece.