Robot Tool Center Point Calibration Using Laser Sensor
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Solution Overview
Problem
Manual calibration of the Tool Center Point (TCP) in robot manipulators is time-consuming and lacks precision due to potential alignment errors between the tool and the robot manipulator, affecting the operating accuracy.
Innovation Solution
A calibration method using a laser displacement sensor and an assistant indicating tool with inclined surfaces to accurately measure and correct the TCP position by establishing a preset and new coordinate systems, adjusting position parameters, and iteratively reducing deviations to achieve precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual calibration method is used, then the calibration process is simple to operate, but the calibration precision is low and time-consuming
Solution Approach 1:
The patent replaces manual mechanical calibration with an optical measurement system. A laser displacement sensor automatically measures the position of the TCP by detecting the reflected light from the calibration tool, eliminating the need for manual measurement and calculation while significantly improving precision and reducing calibration time.
Solution Approach 2:
The patent introduces a calibration tool with a specific reflective surface as an intermediary between the laser sensor and the TCP. This calibration tool serves as a mediator that enables precise optical measurement of the TCP position, allowing the system to accurately determine coordinates without direct contact or manual intervention.
2Reliability
If manual calibration is performed, then no additional calibration equipment is needed, but alignment errors occur between tool and robot manipulator
Solution Approach 1:
The calibration tool with a specifically designed reflective surface acts as an intermediary that establishes a precise reference frame. This mediator enables the laser sensor to accurately measure the TCP position by providing a known geometric reference, thereby eliminating alignment errors between the tool and robot manipulator.
Solution Approach 2:
The patent replaces manual alignment procedures with an optical measurement system. The laser displacement sensor automatically measures positions and calculates coordinates through optical means, eliminating human error in alignment while maintaining system simplicity through software-based coordinate transformation.
3Measurement precision
If iterative calibration method is used, then TCP position accuracy is improved, but calibration process complexity increases
Solution Approach 1:
The patent implements an iterative calibration process where the laser sensor measures the TCP position, the system calculates deviation from the expected position, and adjusts the measurement accordingly. This feedback loop continues until the deviation is within acceptable tolerance, ensuring high accuracy while automating the complexity through software control.
Solution Approach 2:
The calibration system performs self-correction through automated iterative measurement and calculation. The software automatically processes the measurement data, calculates coordinate transformations, and refines the TCP position determination without requiring manual intervention, thereby managing process complexity through automation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method ensures high accuracy in determining the TCP position, reducing alignment errors and improving the precision of robot manipulator operations by iteratively correcting deviations within acceptable limits.
Implementation Method 1
a laser displacement sensor (17) mounted on a distal end of the tool (15) for detecting or measuring a distance between the sensor (17) and the assistant indicating tool (200)
Implementation Method 2
The sensor (17) emits a laser beam towards the inclined surface (201) and measures a distance between a position and a projected point of the laser beam on the inclined surface (201)
Data Source
AI summary
A calibration method for calibration a tool center point for a robot manipulator includes the steps of: driving the tool to move above one of the inclined surfaces; defining a preset coordinate system TG; rotating the TCP relative to the UG-axis by about 180 degrees, calculating the value of Δw; updating the position parameters of the preset TCP, defining a new preset coordinate system TG′; rotating the TCP relative to the UG′-axis by about 90 degrees, calculating the value of Δv; updating the position parameters of the new preset TCP, defining a new preset coordinate system TG″; driving the tool to move above a planar horizontal surface; rotating the TCP relative to a axis by about 30 degrees, calculating the value of Δu; repeating the aforementioned steps until the deviation ΔP (Δw, Δv, Δu) is less than or equal to a maximum allowable deviation of the robot manipulator.