Autonomous Transport Vehicle Stability Control

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Solution Overview

Problem

Current storage and retrieval systems in warehouses lack efficient autonomous transport solutions for high-speed movement of case units between storage racks, limiting the speed and flexibility of item transport.

Innovation Solution

The implementation of an autonomous transport vehicle system with multilevel vertical conveyors and bot transfer stations, enabling high-speed transport and random accessibility to storage spaces, using independently driven wheels and swivelable casters for stability and steering, along with a control system for navigation and position estimation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If autonomous transport vehicles are used for high-speed transport, then productivity and speed are improved, but stability control becomes more difficult

Engineering Contradiction:
Improvetransport speedVSAvoidvehicle stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The bot employs dynamically adjustable caster wheels that can change their locking state based on operational conditions. During high-speed transport, the casters lock to provide stability, while during steering maneuvers, they unlock to allow directional changes. This dynamic adaptation resolves the contradiction between speed and stability by making the stability characteristic variable rather than fixed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the stability parameter of the bot by controlling the locking mechanism of the caster wheels. When high stability is needed during high-speed movement, the casters are locked in place. When maneuverability is needed for steering, the casters are unlocked. This parameter change allows the bot to maintain both high-speed capability and stability control.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If mechanically guided transport systems are used, then stability is improved, but adaptability and flexibility are reduced

Engineering Contradiction:
Improvetransport stabilityVSAvoidaccessibility to storage spaces
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The invention extracts the guidance function from fixed mechanical guides and transfers it to the autonomous bot's own navigation system. The bot uses sensors, controllers, and onboard computing to determine its position and navigate to storage spaces without relying on external mechanical guidance infrastructure. This extraction provides both stability through active control and adaptability through programmable navigation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The bot performs its own navigation and positioning tasks using onboard sensors and control systems rather than relying on external mechanical guidance. The system independently determines its location, plans routes, and executes maneuvers to access storage spaces, providing both stability through self-correction and adaptability through autonomous decision-making.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS9946265B2Bot having high speed stability
Publication Date: 2018.04.17 SYMBOTIC LLC
  • US9946265B2 patent drawing
  • US9946265B2 patent drawing
  • US9946265B2 patent drawing

AI summary

An autonomous transport vehicle for transporting items in a storage and retrieval system is provided. The autonomous transport vehicle includes at least two drive wheels and a controller, where each drive wheel is independently driven and a drive wheel encoder is disposed adjacent each drive wheel. The controller, in communication with the drive wheel encoders, is configured to determine a kinematic state of the autonomous transport vehicle within the storage and retrieval system based on incremental data from the drive wheel encoders only and independent of drive wheel slippage.