Multi-Robot Load Balancing via Conveyor Encoder Synchronization

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing pick and place robot systems with multiple robots on a conveyor face challenges in accurately establishing a common reference frame and load balancing, leading to inefficiencies and errors in part location and processing.

Innovation Solution

A system comprising multiple robots and controllers with integrated load re-balance, state change detection, communication, and motion control subsystems, allowing for workload adjustment, automated load migration, and conveyor encoder synchronization, enabling efficient load distribution and minimizing downtime due to faulty robots.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple robots work on a conveyor with a common reference frame, then the system can perform pick and place operations, but the complexity of establishing and maintaining accurate track frames increases

Engineering Contradiction:
Improvepick and place operation capabilityVSAvoidtrack frame establishment and maintenance
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system uses the conveyor's own encoder as a reference source. Each robot controller independently calculates its track frame by measuring the encoder position when the robot is at a known reference location on the conveyor, eliminating the need for manual track frame teaching or external reference systems.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system continuously monitors conveyor encoder positions and uses this feedback to dynamically adjust and maintain track frames. When conveyor position changes are detected, the system automatically updates the track frame calculations to maintain accuracy without manual intervention.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If the track frame is not set up accurately, then the robot cannot locate and pick up parts, but manual track frame setup is time-consuming and error-prone

Engineering Contradiction:
Improvetrack frame accuracyVSAvoidtrack frame setup time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The robot controller automatically determines its track frame by reading the conveyor encoder at a known reference position. This self-calibration process eliminates manual track frame teaching, reducing setup time and eliminating human error while achieving high precision through encoder-based measurement.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system replaces manual mechanical track frame setup with an automated electronic calibration process using the conveyor encoder. The controller software automatically calculates track frame parameters based on encoder readings, substituting manual measurement and calculation with automated electronic determination.

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

3Reliability

If one robot fails or changes state, then the system downtime increases, but load balancing requires continuous monitoring and adjustment

Engineering Contradiction:
Improvesystem continuityVSAvoidload monitoring and re-balancing system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The load re-balance subsystem continuously monitors the state of each robot and automatically detects when a robot fails or changes state. Based on this feedback, the system dynamically recalculates and redistributes the workload among remaining operational robots, maintaining system continuity without manual intervention.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system implements dynamic load balancing where workload distribution is continuously adjusted based on real-time robot status. When robot states change, the load re-balance subsystem automatically recalculates optimal workload distribution and implements changes, allowing the system to adapt dynamically to failures or state changes.

Inventive Principle:
Principle #15Dynamics

4Measurement precision

If conveyor encoder synchronization is required across multiple robots, then positioning accuracy improves, but the complexity of encoder value communication and synchronization increases

Engineering Contradiction:
Improveconveyor position accuracyVSAvoidencoder synchronization system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system merges the encoder reference function into a single centralized subsystem. One robot controller acts as the encoder reference source, and other robot controllers receive and synchronize to this single encoder signal. This consolidation eliminates the need for each robot to independently process encoder signals, reducing overall system complexity while maintaining synchronization accuracy.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentUS8315736B2Method and apparatus for picking/packing applications
Publication Date: 2012.11.20 FANUC ROBOTICS NORTH AMERICA INC
  • US8315736B2 patent drawing
  • US8315736B2 patent drawing
  • US8315736B2 patent drawing

AI summary

A system for picking and packing applications is provided. The system includes a plurality of robots and a plurality of robot controllers. Each robot controller includes a load re-balance subsystem, a load balance subsystem, a robot state change detector subsystem, a communicator subsystem, and a motion control subsystem. Each of the robot controllers is interconnected and in communication with one another via the communicator subsystems. Each of the robots has a workload that may be selectively balanced. A method for balancing the workloads of the robots using built-in processors which run motion control is also provided.