AGV Workpiece Fixture Positioning With Adjustable Locators
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Solution Overview
Problem
Conventional workpiece positioning methods in manufacturing, such as those used in automobile body assembly, suffer from dimensional variability due to material inconsistencies and processing variations, leading to quality issues, scrap, and reduced production efficiency, as they rely on manual adjustments and trial-and-error techniques with fixed locator pins that can cause stress and wear.
Innovation Solution
An automated system using an automatic guided vehicle (AGV) and machine vision to measure and adjust the spatial position of a workpiece fixture with adjustable locators, driven by motors controlled by a computer processor, allowing precise positioning of the workpiece to a nominal work position, reducing variability and stress on components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fixed locator pins are used in conventional workpiece fixtures, then the fixture structure is simple and easy to manufacture, but dimensional variability increases and manufacturing precision deteriorates
Solution Approach 1:
The patent applies dynamics by making the locator pins adjustable rather than fixed. The locator pins can be repositioned along the fixture structure to accommodate variations in workpiece hole positions. This dynamic adjustment capability allows the fixture to adapt to dimensional variations in stamped body components while maintaining manufacturing precision, resolving the contradiction between positioning accuracy and fixture complexity.
Solution Approach 2:
The patent implements parameter changes by allowing the locator pin positions to be modified based on measured workpiece variations. The system measures actual hole positions and adjusts locator pin locations accordingly, changing the spatial parameters of the fixture to match the specific workpiece being assembled. This resolves the contradiction by enabling precise positioning without requiring an entirely complex fixture design.
2Reliability
If locator pins are sized to the largest possible diameter to eliminate positioning errors, then positioning stability improves, but stress on the body component and locator pin increases causing wear and failure
Solution Approach 1:
The patent applies local quality by making each locator pin's diameter and position specific to the local requirements of each workpiece hole. Instead of using a uniform oversized locator pin that causes stress everywhere, the system adjusts each locator pin's size and position to match the specific hole it engages. This localized adaptation maintains positioning stability while minimizing stress and wear on both the locator pins and body components.
Solution Approach 2:
The patent uses dynamics by making locator pins adjustable in both position and potentially size to match each specific workpiece configuration. This dynamic adaptation allows the system to achieve reliable positioning without applying excessive stress, as each locator pin is optimized for its specific engagement point rather than being a fixed oversized component that causes wear.
3Productivity
If manual trial-and-error techniques are used to reposition locators, then device complexity remains low, but loss of time increases and productivity decreases
Solution Approach 1:
The patent replaces manual mechanical adjustment with an automated measurement and adjustment system. Machine vision or laser sensors automatically measure workpiece hole positions, and this data is used to automatically reposition locator pins without manual intervention. This substitution of automated systems for manual trial-and-error dramatically reduces the time required for tooling corrections and increases assembly line throughput.
Solution Approach 2:
The patent implements self-service by enabling the fixture system to automatically measure workpiece dimensions and adjust its own locator pin positions without external intervention. The system uses automated measurement data to self-correct positioning errors, eliminating the need for manual measurement and adjustment operations that consume time and reduce productivity.
4Adaptability or versatility
If conventional fixtures rely on nominal part geometry and historic sample data, then device complexity is reduced, but adaptability to actual part variations deteriorates
Solution Approach 1:
The patent implements feedback by using automated measurement systems (machine vision or laser sensors) to measure actual workpiece hole positions and using this measurement data to adjust locator pin positions. This closed-loop feedback system enables the fixture to adapt to actual part variations in real-time, significantly improving adaptability while the automation manages the complexity of the adjustment process.
Solution Approach 2:
The patent applies universality by creating a fixture system that can accommodate multiple different workpiece variations through its adjustable locator pins. The same fixture structure with adjustable locators can handle various body component configurations and tolerance ranges, making the system universally applicable to different part variations without requiring entirely different fixtures for each case.
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 approach enables more precise manufacturing operations, reduces dimensional variation, minimizes tooling failures, and increases production throughput by allowing real-time adjustments to accommodate the specific tolerance and configuration of body parts, thereby improving product quality and reducing downtime.
Implementation Method 1
measuring, by machine vision, spatial position of the workpiece fixture
Implementation Method 2
the one or more adjustable locators are driven by respective motors which are controlled by the computer processor
Data Source
AI summary
A method is presented for positioning a workpiece in a workstation. The method includes: transporting a workpiece into a workstation using an automatic guided vehicle, where the workpiece is supported by a workpiece fixture and the workpiece fixture is supported by the automatic guided vehicle; measuring spatial position of the workpiece fixture; removing the workpiece fixture from the automatic guided vehicle using one or more adjustable locators mounted on a frame of the workstation; calculating an adjustment to position of the workpiece fixture between the measured spatial position of the workpiece fixture and a nominal work position; moving the workpiece fixture suing the one or more adjustable locators to the nominal work position according to calculated adjustment; performing an operation on the workpiece while the workpiece fixture remains in the nominal work position; and returning the workpiece fixture to the automatic guided vehicle.