Robot Arm Speed Control for Human Collaboration

Solution Overview

Problem

Conventional robot systems restrict arm swivel and travel operations when coordinated, limiting the maximum speed of the robot's distal end, which can interfere with human workers in the vicinity.

Innovation Solution

A robot system that includes a conveyor speed detection unit, a worker state input unit, and a control unit with tracking speed calculation, relative movement speed calculation, movement command generation, and speed limit switching units to adjust the robot's movement speed based on conveyor speed and worker presence, allowing the robot to move at maximum speed when alone and reducing speed when a worker is nearby.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the robot moves at maximum speed to maintain productivity, then work efficiency is improved, but safety for nearby workers deteriorates

Engineering Contradiction:

Improvework efficiencyVSAvoidsafety for nearby workers

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The robot system dynamically adjusts its movement speed based on the presence and state of nearby workers. When a worker is detected in the collaboration area, the robot automatically reduces its speed to a safe level. When no worker is present, the robot operates at maximum speed to maintain productivity. This dynamic speed adjustment resolves the contradiction between productivity and worker safety.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system uses sensors to continuously detect the presence and state of workers near the robot, and this information feeds back to the control unit which adjusts the robot's speed accordingly. This feedback mechanism enables the robot to respond to worker presence in real-time, maintaining safety while preserving productivity when the area is clear.

Inventive Principle:

Principle #23Feedback

2Object-affected harmful factors

If the robot reduces speed to ensure worker safety, then safety for nearby workers is improved, but work efficiency deteriorates

Engineering Contradiction:

Improvesafety for nearby workersVSAvoidwork efficiency

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The robot system dynamically adjusts its movement speed based on the presence and state of nearby workers. When a worker is detected in the collaboration area, the robot automatically reduces its speed to a safe level. When no worker is present, the robot operates at maximum speed to maintain productivity. This dynamic speed adjustment resolves the contradiction between productivity and worker safety.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The speed limitation is applied locally and selectively - only when a worker is detected in the collaboration area. The robot maintains different speed characteristics in different spatial and temporal contexts: high speed in safe conditions, reduced speed when workers are present. This localized application of speed control prevents unnecessary productivity loss while ensuring safety when needed.

Inventive Principle:

Principle #3Local quality

3Productivity

If the robot operates at maximum speed, then productivity is improved, but the robot cannot respond to worker presence deteriorates

Engineering Contradiction:

ImproveproductivityVSAvoidresponse to worker presence

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The robot system dynamically adjusts its movement speed based on the presence and state of nearby workers. When a worker is detected in the collaboration area, the robot automatically reduces its speed to a safe level. When no worker is present, the robot operates at maximum speed to maintain productivity. This dynamic speed adjustment resolves the contradiction between productivity and worker safety.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system continuously and periodically scans for worker presence using sensors, and adjusts robot speed in periodic cycles based on detected conditions. This periodic monitoring and adjustment enables the robot to maintain maximum productivity during safe periods while quickly responding to worker presence when it occurs.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS10525592B2Robot system

Publication Date: 2020.01.07 FANUC LTD

AI summary

Provided is a robot system includes a conveyor; a conveyor speed detection unit for detecting a movement speed of the conveyor; a robot for performing a task on the workpiece; a worker state input unit for inputting a collaboration state of a worker; and a control unit for controlling the robot based on the movement speed and the collaboration state of the worker. The control unit calculates a first speed based on the movement speed of the conveyor, calculates a second speed of a distal end of an arm of the robot, in a direction intersecting a direction of the first speed, causes the distal end of the arm to move at a speed combining the first speed and the second speed, and limits the second speed, when the collaboration state of the worker is input.