Wafer Handling Robot Slip Detection From Motor Feedback
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Solution Overview
Problem
Existing systems for detecting slippage between a wafer and a holding part of a robot during transportation require additional position detection sensors, increasing complexity and cost, and fail to detect slippage in real-time.
Innovation Solution
A robot system that uses a control part to determine slippage based on information from electric motors, allowing immediate detection and estimation of slippage without additional detection devices or special robot movements, and adjusts the transfer route accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a position detection sensor is added to detect wafer deviation during transport, then the wafer position can be detected, but the system complexity and cost increase
Solution Approach 1:
The robot system uses its own motor information to detect wafer slippage, making the robot self-diagnostic without requiring external detection sensors. The control part monitors motor current, position, velocity, or acceleration during wafer transport and automatically determines slippage occurrence based on deviations from expected values, enabling the system to detect problems using its inherent operational data
Solution Approach 2:
The invention extracts the detection function from separate external sensors and integrates it into the robot's control system by utilizing existing motor information. Instead of adding a position detection sensor, the system extracts slippage detection capability from the motor's operational parameters that are already being monitored for control purposes
2Measurement precision
If a position detection sensor is used to detect wafer deviation, then positional deviation can be detected, but slippage occurrence cannot be detected immediately
Solution Approach 1:
The system performs preliminary monitoring of motor parameters during wafer transport to detect slippage as it occurs. By continuously monitoring motor current, position, velocity, or acceleration during the transport process itself, the system can immediately identify slippage events rather than detecting them only after the wafer has moved past a detection sensor
Solution Approach 2:
The control part uses real-time feedback from motor information to detect slippage during transport. The system compares actual motor parameter values against expected values during wafer movement, and when deviations exceed predetermined thresholds, slippage is immediately determined, enabling real-time detection and response
3Measurement precision
If additional position detection sensors are provided to detect slippage, then detection accuracy improves, but manufacturing cost increases
Solution Approach 1:
The robot's motor information serves multiple functions: it controls robot movement and simultaneously detects wafer slippage. The same motor sensors and control circuits that are already present for robot operation are utilized for slippage detection, making the system multi-functional without requiring additional dedicated detection hardware
Solution Approach 2:
The invention uses inexpensive, readily available motor information that is already part of the robot's standard equipment. Rather than investing in expensive specialized position detection sensors, the system leverages the existing motor control infrastructure to achieve slippage detection functionality
Data Source
AI summary
A robot system according to one or more embodiments may include a robot, and a control part. The robot may include one or more joints driven by an electric motor, and can hold a wafer by a holding part. The control part gives commands to the robot for control. When the robot holds and transports the wafer with the holding part, the control part performs, based on information about the electric motor, at least one of the following: determining whether slippage has occurred between the holding part and the wafer; and estimating an amount of slippage of the wafer relative to the holding part.