Auto Guide Vehicle Partial Lift Stability
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Solution Overview
Problem
Existing auto guide vehicle systems face challenges in stabilizing cart transport, including increased costs from modifying carts and the risk of cart tipping due to unbalanced loads, especially when using lift devices that lift wheels off the floor.
Innovation Solution
An auto guide vehicle equipped with a fluid pressure cylinder, pressure regulating system, and control board that estimates the timing for the cart to leave the ground based on pressure derivatives, distributing the weight to ensure stable transport using both wheels and casters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the cart is completely lifted by a lift device provided in the AGV, then the AGV can transport the cart, but the wheels of the cart leave the floor surface creating a risk of the cart tipping over if the cargo is unbalanced
Solution Approach 1:
The air cylinder lifts the cart partially (approximately 20mm) rather than completely, maintaining wheel contact with the floor surface to prevent tipping while enabling transport. This partial lifting action resolves the contradiction by providing enough elevation for transport capability while retaining ground contact for stability.
2Adaptability or versatility
If coupling grooves are provided in the bottom surface of carts to enable pin-coupling with AGV, then the towing system can function, but costs increase significantly especially when large numbers of carts need modification
Solution Approach 1:
Instead of modifying the cart bottom surface with coupling grooves, the invention inverts the approach by having the AGV's air cylinder ascend from underneath the cart and contact the cart's bottom surface directly. This eliminates the need for cart modifications while achieving the same coupling and lifting functionality.
3Reliability
If the air cylinder is moved so that a receiving plate that contacts the cart is made horizontal, then the cart stability improves, but the AGV body becomes heavy to keep the drive wheels from slipping
Solution Approach 1:
The invention changes the parameter of lift height to approximately 20mm, which allows the receiving plate to contact the cart at a horizontal position for stability while keeping the AGV body weight manageable. This parameter optimization resolves the contradiction between stability and weight.
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
The system allows for stable cart transport by distributing the weight of the cart and cargo, preventing tipping and reducing costs associated with cart modifications, while maintaining stability with unbalanced loads.
Implementation Method 1
a fluid pressure cylinder that is able to be extended and retracted vertically, and that applies an upward pressing force to the floor surface of the cart; a fluid pressure supply device that supplies a fluid to the fluid pressure cylinder
Data Source
AI summary
An auto guide vehicle (20) that conveys a cart (10), wherein the auto guide vehicle (20) is provided with: a fluid pressure cylinder (22) that is able to be extended and retracted vertically, and that applies an upward pressing force to the floor surface of the cart (10); a fluid pressure supply device (70) that supplies a fluid to the fluid pressure cylinder (22); pressure regulating means (50) that regulates the fluid pressure of the fluid supplied from the fluid pressure supply device (70) to the fluid pressure cylinder (22); a control board (40) that outputs a fluid pressure command value to the pressure regulating means (50); and a pressure sensor (100) that detects the fluid pressure of the fluid supplied to the fluid pressure cylinder (22); wherein the control board (40) computes derivatives of the fluid pressure detected by the pressure sensor (100), estimates a timing at which the cart begins to leave the ground based on a pattern of the computed derivatives, and computes the command value by multiplying a coefficient less than one by the fluid pressure detected by the pressure sensor (100) at the estimated timing.