Manufacturing Machinery World October 2021

ROBOTICS & AUTOMATION
TIPS FOR CHOOSING A 3D VISION SYSTEM
THE FUTURE OF VISION SYSTEMS IN MANUFACTURING
With four times as many as colour receptors
as humans, the Mantis shrimp has the most
impressive eyes in nature. Manufacturers
have long relied on human vision for
complex picking and assembly processes, but
3D vision systems are beginning to replicate
the capability of human vision in robotics.
Here, Nigel Smith, managing director of
Shibaura Machine, formerly Toshiba
Machine, partner, TM Robotics, gives three
rules to live by when choosing a 3D vision
system for manufacturing.
Advanced 3D vision systems are a stark
contrast to the vision software of
manufacturing’s past. Many existing systems
still require professional CAD programming
to ensure the robot can recognise shapes.
However, even after programming, this
software can have difficulties recognising
multiple items at once.
A common application for vision systems
is removing and sorting items from a bin.
While CAD-based systems can identify items
in a bin, the challenge is recognising the
position of each item when presented in a
random order — let alone determining the
best method for the robot pick them in.
Advanced vision systems eliminate this
problem by using passive imaging to enable
the robot to automatically identify items,
regardless of their shape or order.
Shibaura Machine’s vision system,
TSVision3D, for example, uses two highspeed
cameras to continuously capture 3D
images. Using intelligent software, the
system can process these images and identify
the exact position of an item. This determines
the most logical order to pick them up and
does so with sub millimetre accuracy, with
the same ease as a human worker.
Deploying a robot for bin-picking isn’t
advantageous if the robot cannot identify the
edges of the bin. Considering the speed and
strength of most 6-axis robots, hitting the box
sides could easily halt production or damage
the product.
Some manufacturers believe that motion
stereo systems can effectively imitate a
human’s perception of an item. Motion stereo
systems use one camera, usually mounted on
a robotic arm, to enable the system to move
and take two or more photographs of an
object. However, these systems require
absolute precision as even the slightest
movement can cause disparities in data and
skew the measurement.
For manufacturers hoping to automate
their box-picking processes, they should
identify whether the system has a collision
avoidance function. Advanced systems,
including TSVision3D, enable the system to
be programmed according to the size of the
bin, ensuring the robot can dive into the box
without a hitch.
Automation for jobs like bin-picking are
designed to free manual operators from
repetitive and menial tasks and speed up
operations. However, some traditional vision
systems involved multiple hurdles to
implement, including longwinded
installation methods and high levels of
technical know-how.
Using 3D vision systems for bin-picking,
cycle times can be as fast as 0.7 seconds. But,
these productivity gains are useless if
implementation of the software has high
costs for time and staff resources.
When choosing a system, manufacturers
must strike a balance between potential
productivity gains and the resources
required for installation. Today,
manufacturers should opt for software that
anyone, even with minimal training, can
understand.
Eyes are a testament to evolution’s
creativity. While they all have the same basic
duty, the more advanced the vision system,
the more information it can acquire. When
choosing a vision system for manufacturing
applications, manufacturers should consider
how the system will improve their process,
how it will manage complex requirements
and commercial applications.
www.tmrobotics.co.uk
24 Manufacturing Machinery World, October 2021