Collaborative Robot Tool Collision Shell With Dual-Channel Stop
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Solution Overview
Problem
Conventional collision protection devices for collaborative robots fail to meet safety criteria for human-robot collaboration, particularly in applications where tools attached to robot gripper arms may cause unintended high counterforces during collisions, leading to potential injuries.
Innovation Solution
A tool with an integrated collision protection device featuring 2-channel monitoring using position detection means connected to a programmable logic controller, which activates a tool stopping mechanism upon collision, ensuring the tool retracts to a safe position, thus preventing direct contact and managing counterforces effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If spring-loaded pre-tensioning elements are used to maintain contact force between the tool and workpiece, then the tool remains securely positioned during operation, but excessive counterforce is exerted on the operator during collision
Solution Approach 1:
The collision protection device transitions from a static spring-loaded system to a dynamic system where the contact force can be actively adjusted and released. The device includes a release mechanism that can quickly reduce the preload force when collision is detected, allowing the system to adapt its mechanical properties in real-time based on operational conditions.
Solution Approach 2:
The system changes the mechanical parameter of contact force from a fixed high value (spring preload) to a variable value that can be rapidly reduced. By modifying the force parameter dynamically through the release mechanism, the system maintains strong contact during normal operation while minimizing harmful counterforce during collision events.
2Object-affected harmful factors
If vacuum means are added to reduce preload force during collision, then the counterforce on the operator is reduced, but the device complexity increases
Solution Approach 1:
The patent introduces a vacuum chamber as an intermediary mechanism between the spring elements and the collision protection shell. This vacuum intermediary allows for reduction of the effective contact force during collision without directly modifying the spring preload, thereby reducing counterforce on the operator while maintaining a relatively simple overall device structure.
3Reliability
If 2-channel monitoring with position detection means is implemented, then collision detection reliability is improved, but the device complexity increases
Solution Approach 1:
The monitoring system is segmented into two independent detection channels using separate position detection means. This segmentation allows each sensor to independently monitor collision conditions, and the system can cross-validate signals from both channels to reliably detect collisions while maintaining manageable device complexity through modular architecture.
4Object-affected harmful factors
If the tool insert holder is designed to be displaceable in axial direction, then the tool can retract from working position upon collision, but the device complexity increases
Solution Approach 1:
The collision protection functionality is merged with the existing tool insert holder assembly. The holder is designed to perform both its normal function of holding and positioning the tool insert, and the additional function of retracting upon collision detection. This integration allows the tool to retract from the working position to reduce injury risk without adding a completely separate protection mechanism.
Data Source
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AI summary
The invention relates to a tool (10) for a collaborative robot (120), comprising: - a tool housing (15); - a robot flange (16); - a tool drive (12); - a tool insert holder (30) for receiving a tool insert (35); - a tool insert (35) that can be attached to the tool insert holder (30); - a drive shaft (13) for transmitting a drive torque from the tool drive (12) to the tool insert holder (30) together with the tool insert (35); - a collision protection device (40) with a 2-channel monitoring system (43) with two position detection means (41, 42), which is connected to a programmable logic controller (50) via a signal (46); - a collision protection cover (20) which is arranged at a free end (19) of the tool (10) coaxially with the axis direction (14) of the tool insert (35);wherein - the collision protection shell (20) is movably coupled to a plunger (25) which is mounted to be displaceable in the axial direction (14); wherein - in the event of a collision contact (K1, K2) with the collision protection shell (20), a change in the position of the plunger (25) in the axial direction (14) can be detected by the position detection means (41, 42) and the collision protection device (40) is configured to stop the tool drive (12) (110).;