Weight Sensor Shelf Inventory Tracking via Joint Inference

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Solution Overview

Problem

Traditional systems for tracking inventory movement in facilities are intrusive, require special tags or devices, and are costly, leading to inefficiencies and inaccuracies in monitoring item location and movement.

Innovation Solution

A system utilizing weight sensors at inventory locations to generate sensor data, which is processed to determine interaction data such as item type, quantity, and location, eliminating the need for user-carried devices and improving precision and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional tracking systems with special tags or devices are used, then item location and movement can be monitored, but the system becomes costly and intrusive

Engineering Contradiction:
Improveinventory tracking accuracyVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the tracking functionality from intrusive user-carried devices and special tags, and relocates it to the inventory location itself through weight sensors. This eliminates the need for users to carry scanning devices while maintaining reliable tracking of item movement through automated weight change detection at the shelf level.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system enables inventory locations to self-monitor their own contents through integrated weight sensors. The sensors automatically detect when items are removed or placed without requiring external intervention from users carrying tracking devices, thus reducing system complexity while maintaining reliable tracking.

Inventive Principle:
Principle #25Self-service

2Productivity

If user-carried scanning devices are used, then item interaction can be tracked, but operational efficiency decreases and costs increase

Engineering Contradiction:
Improveoperational efficiencyVSAvoidtime for item tracking
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The weight sensor system operates continuously and automatically detects item movements without interruption. Unlike manual scanning where users must actively scan each item, the sensor system passively and continuously monitors weight changes, eliminating downtime and improving operational efficiency by maintaining constant tracking capability.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent replaces the mechanical action of users manually carrying and operating scanning devices with an automated sensor-based system. The weight sensors automatically detect item removal and placement through weight changes, eliminating the need for manual scanning operations and significantly reducing the time lost to tracking activities.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If RFID tags are required for tracking, then item location can be monitored, but the system becomes less accessible and more expensive

Engineering Contradiction:
Improveitem location accuracyVSAvoidsystem accessibility
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The weight sensor system provides universal tracking capability that works for all items regardless of whether they have RFID tags or not. The sensors detect item movement through weight changes alone, making the system accessible and applicable to diverse item types without requiring special tags, thus improving versatility while maintaining location accuracy.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentUS11308442B1Joint inference determination of interaction using data from weight sensors
Publication Date: 2022.04.19 AMAZON TECH INC
  • US11308442B1 patent drawing
  • US11308442B1 patent drawing
  • US11308442B1 patent drawing

AI summary

Sensor data from load cells at a shelf is processed using a first time window to produce first event data describing coarse and sub-events. Location data is determined that indicates where on the shelf weight changes occurred at particular times. Hypotheses are generated using information about where items are stowed, weights of those of items, type of event, and the location data. If confidence values of these hypotheses are below a threshold value, second event data is determined by merging adjacent sub-events. This second event data is then used to determine second hypotheses which are then assessed. A hypothesis with a high confidence value is used to generate interaction data indicative of picks or places of particular quantities of particular types of items from the shelf.