Robotic End Effector Deformation Detection via Target Pin
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Solution Overview
Problem
Existing methods for detecting deformation in robotic end effectors, such as those used in wafer conveyance robots, rely on multiple contactless sensors that complicate wiring and maintenance, and require specialized equipment.
Innovation Solution
A method using a robotic arm with a deformation detecting device that employs a target pin with a specific shape to indicate when the detection part reaches the target, allowing the system to detect deformation without exclusive contactless sensors, by controlling the robotic arm to touch the target pin and compare the detection part's position with a reference position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple contactless sensors are used to detect deformation of the end effector, then measurement precision is improved, but device complexity increases due to complicated wiring and maintenance
Solution Approach 1:
The patent extracts the deformation detection function from dedicated contactless sensors and transfers it to the robotic arm's existing sensors. The robotic arm's sensors, originally used for position control, are repurposed to detect end effector deformation by monitoring position deviations during contactless measurement operations, thereby eliminating the need for separate deformation sensors and reducing system complexity
Solution Approach 2:
The patent makes the robotic arm's sensors multi-functional by enabling them to perform both their original position control function and the new deformation detection function. The same sensors and processing units are used for both operational control and diagnostic measurement, achieving universal functionality without adding dedicated deformation detection equipment
2Measurement precision
If periodic deformation detection is conducted by disassembling the device, then measurement precision is improved, but productivity decreases due to operational interruptions
Solution Approach 1:
The patent enables continuous deformation monitoring during the robotic arm's normal operation without requiring device disassembly or operational interruption. The system continuously compares actual sensor readings with expected values during wafer conveyance operations, allowing real-time deformation detection while maintaining uninterrupted productivity
Solution Approach 2:
The patent replaces the mechanical disassembly-based detection method with a contactless sensor-based detection method. Instead of physically accessing and measuring the end effector during disassembly, the system uses the robotic arm's existing sensors to detect deformation through non-contact position measurement, eliminating the need to stop operations for inspection
3Device complexity
If the robotic arm structure is simplified without exclusive sensors, then device complexity is reduced, but measurement precision may deteriorate
Solution Approach 1:
The patent implements a feedback mechanism where the robotic arm's sensors continuously monitor position data during operations, and the control unit compares actual readings with expected values to detect deformation. This feedback loop ensures that deformation detection precision is maintained by continuously validating measurements against known reference positions, compensating for the absence of dedicated sensors
Solution Approach 2:
The patent performs preliminary calibration by storing expected sensor readings for various positions in the robotic arm's operation range before actual operations begin. This pre-stored reference data enables accurate deformation detection by comparing real-time readings against known good values, ensuring measurement precision is maintained without requiring complex real-time calculation systems
Data Source
AI summary
A robot system includes a robotic arm having a wrist in a tip-end part thereof, the wrist being rotatable on a rotational axis extending in a given direction, an end effector attached to the wrist, and a deformation detecting device configured to detect deformation of the end effector by using a target pin having a target part where a given detection part of the end effector reaches. The target part has an indicate function to indicate that the detection part reaches the target part. The deformation detecting device includes a search part configured to control the robotic arm so that the detection part touches the target pin to search for the target part, and detect that the detection part reaches the target part based on the indicate function, and a deformation detecting part configured to compare an assumed position of the detection part when the detection part reaches the target part with a given reference position, and detect the deformation of the end effector.