Actuator Parameter Data Payload Characterization

Solution Overview

Problem

Conventional motion control systems for autonomous machines are excessively slow and inefficient due to worst-case assumption requirements for changing payload characteristics, leading to prolonged task completion times and increased costs.

Innovation Solution

A payload characterization module within the mobile drive unit uses actuator parameter data, such as motor current measurements, to determine payload properties like mass and center of gravity, allowing for optimized motion control and reduced worst-case assumptions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If worst case assumptions are used for payload characteristics, then safety is improved, but motion speed decreases

Engineering Contradiction:

ImprovesafetyVSAvoidmotion speed

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The system performs preliminary characterization of payload characteristics by analyzing actuator parameter data before motion execution. This advance knowledge of actual payload properties (mass, center of gravity, moment of inertia) replaces conservative worst-case assumptions, enabling optimized motion planning that maintains safety while improving speed.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously collects actuator parameter data during operation and uses this feedback to determine actual payload characteristics. This real-time feedback mechanism allows the control system to adapt motion parameters based on measured payload properties rather than relying on predetermined worst-case values, resolving the contradiction between safety and speed.

Inventive Principle:

Principle #23Feedback

2Reliability

If worst case assumptions are used for payload characteristics, then safety is improved, but task completion time increases

Engineering Contradiction:

ImprovesafetyVSAvoidtask completion time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary characterization of payload characteristics by analyzing actuator parameter data before motion execution. This advance knowledge of actual payload properties (mass, center of gravity, moment of inertia) replaces conservative worst-case assumptions, enabling optimized motion planning that maintains safety while improving speed.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously collects actuator parameter data during operation and uses this feedback to determine actual payload characteristics. This real-time feedback mechanism allows the control system to adapt motion parameters based on measured payload properties rather than relying on predetermined worst-case values, resolving the contradiction between safety and speed.

Inventive Principle:

Principle #23Feedback

3Productivity

If actuator parameter data is used to determine payload characteristics, then motion efficiency is improved, but measurement complexity increases

Engineering Contradiction:

Improvemotion efficiencyVSAvoidmeasurement complexity

Core Design Contradiction:

ProductivityVSDifficulty of detecting and measuring

Solution Approach 1:

The system uses the actuator's own operational parameter data (current, voltage, temperature) to characterize payload properties. The actuator effectively measures payload characteristics through its normal operation without requiring separate measurement devices. This self-service approach improves motion efficiency while avoiding additional measurement complexity.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The actuator serves multiple functions: it provides motion control and simultaneously characterizes payload properties through its operational parameter data. This multi-functionality eliminates the need for dedicated measurement systems, improving productivity without increasing measurement complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 faster and more efficient payload transport by accurately determining payload characteristics, reducing unnecessary safety constraints and enhancing operational efficiency.

Implementation Method 1

A payload characterization module of a mobile drive unit may obtain information about payload characteristics based on measurements of operational parameters (e.g., electric currents) of actuators

Methodology Applied

Scientific EffectElectrical current measurement: Ohm's Law

Data Source

PatentUS10336150B1Determining payload properties using actuator parameter data

Publication Date: 2019.07.02 AMAZON TECH INC

AI summary

Payload properties may be determined utilizing actuator parameter data. A mobile drive unit may transport a payload around a workspace in accordance with one or more safety. To comply with safety policies, a motion controller of the mobile drive unit may limit acceleration and deceleration to safe maximums for given payload characteristics such as payload mass and payload center of gravity. The motion controller may utilize actuators to cause various motions of the mobile drive unit, including motion across a surface, vertical movements of the payload and motion rotating the payload. To ameliorate worst case assumptions about payload characteristics, in accordance with at least one embodiment of the invention, a payload characterization module may obtain information about payload characteristics based on measurements of operational parameters of the actuators. Utilizing motor current data provides a relatively inexpensive mechanism for obtaining such information compared to special purpose sensors, enabling widespread adoption.