Independent Cart Orientation Sensing for Closed-Loop Actuator Control

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Solution Overview

Problem

In independent cart systems, variations in manufacturing tolerances, wear, and loading conditions lead to inconsistencies in the orientation of movers along a track, making precise real-time orientation of carts or end effectors challenging, especially when interacting with external actuators or devices.

Innovation Solution

A system with sensors, such as accelerometers, gyroscopes, and compasses mounted on each cart, providing multi-axis feedback signals to a remote controller, enabling real-time orientation determination and wireless communication to adjust actuator positions and control external devices accurately.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional conveyor belt systems are replaced with independent cart systems, then flexibility and speed are improved, but manufacturing precision and orientation consistency deteriorate due to tolerances and wear

Engineering Contradiction:
ImprovespeedVSAvoidorientation consistency
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies feedback by mounting sensors (accelerometers, gyroscopes, compasses) on each cart to continuously measure orientation in real-time. This feedback is transmitted to a controller that calculates deviations from the expected orientation and compensates for them, thereby maintaining manufacturing precision while using flexible independent cart systems.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces mechanical orientation assurance (relying on precise mechanical manufacturing and alignment) with an electronic/sensor-based system. Instead of depending on mechanical tolerances, the system uses electronic sensors and computational compensation to achieve and maintain orientation accuracy.

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

2Measurement precision

If sensors are added to each cart for real-time orientation measurement, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveorientation measurement accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses multi-functional sensors (such as 9-axis IMUs combining accelerometers, gyroscopes, and compasses) that provide multiple orientation measurements simultaneously. This multi-functionality improves measurement precision while minimizing the number of separate components needed, thereby limiting the increase in device complexity.

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

3Adaptability or versatility

If real-time orientation feedback is implemented, then adaptability is improved, but loss of information increases due to wireless communication requirements

Engineering Contradiction:
Improveadaptive motion controlVSAvoiddata transmission accuracy
Core Design Contradiction:
Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent introduces a controller as an intermediary that receives sensor data from the cart, processes the orientation information locally, and then transmits only the essential control parameters to external actuators. This intermediary processing reduces the amount of data that needs to be transmitted wirelessly, thereby minimizing information loss while maintaining adaptability.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables precise real-time orientation feedback, allowing for closed-loop control and adaptive motion control, improving the accuracy and flexibility of interactions between carts and external devices by compensating for variations due to wear, vibration, and other factors.

Implementation Method 1

A sensor is provided on each cart to determine orientation of the cart for a predefined coordinate system

Methodology Applied
Scientific EffectAccelerometer: Accelerometer

Implementation Method 2

sensors, such as accelerometers, gyroscopes, and compasses mounted on each cart

Methodology Applied
Scientific EffectGyroscope: Gyroscope

Implementation Method 3

sensors, such as accelerometers, gyroscopes, and compasses mounted on each cart

Methodology Applied
Scientific EffectMagnetic Field: Magnetic Field

Data Source

PatentEP4071569B1System and method for determining real-time orientation on carts in an independent cart system
Publication Date: 2024.08.28 ROCKWELL AUTOMATION TECH INC
  • EP4071569B1 patent drawingFigure 1
  • EP4071569B1 patent drawingFigure 2
  • EP4071569B1 patent drawingFigure 3

AI summary

A system and method of determining orientation of a physical location on a cart or end effector located on the cart in an independent cart system receives a feedback signal from a sensor on the cart. A multi-axis device may generate three or more signals corresponding to X, Y, and Z axes orientations. Processing may be performed on the signals to generate a value of yaw, pitch, or roll of the cart. The feedback or processed signals are transmitted from the mover to a remote device external from the track. The real-time orientation information may be used to implement closed-loop control of an actuator mounted on or external to each cart as the cart travels along the track. Power for the devices on the mover may be provided by a battery mounted on the cart or by a wireless power transfer system.