ROBOTICS
BATTERIES NOT INCLUDED
ACCUTRONICS
WHY YOU CAN’T AFFORD TO
IGNORE ROBOT BATTERIES
One of the key reasons for using an industrial robot to automate a
process is to improve product quality, through increased reliability
and accuracy. But for robots to be truly reliable and safe, engineers
should ensure they have the correct power solutions. Here, Michele
Windsor, global marketing manager at robot battery specialist
Ultralife Corporation, explains the impact poor design and
integration of batteries can have on industrial robots.
In a survey conducted by the journal Science Robotics, researchers
revealed that power and energy sources represent one of the most
challenging areas of robotics research. With a multitude of potential
applications, this is particularly important for robots operating
outside the confines of a cage, untethered from an electrical outlet
and working alongside human employees.
For instance, autonomous mobile robots and automated guided
vehicles, such as Omron’s series of LD self navigating autonomous
intelligent vehicles and Kuka’s KMR series of mobile robots have
become commonplace sites at trade shows and in industry.
Because they can’t constantly connect to a power supply like a
traditional industrial robot, their power requirements are far more
complex.
The report goes on to say, “Beyond the currently available
commercial technologies such as lead-acid, nickel-metal hydride
and lithium-ion batteries, there has already been extensive research
on developing next-generation technologies such as fuel cells and
supercapacitors”.
LOSING IT ALL
If any robot, collaborative, mobile or traditional, were to lose power
mid-application, it can have a devastating effect. For industries such
as food and beverage or pharmaceuticals, downtime can result in
loss of product and profit. For robots in the medical sector, loss of
power could result in surgeons having to operate manually, which
may not be as accurate, in-turn increasing potential risk. More likely,
it would result in the surgery being cancelled.
In addition, power failure can also mean a robot loses calibration
and mastering values. Calibration establishes the parameters in the
kinematic structure of a robot, such as the position of its joints, tool-
centre-point (TCP) positions and joint lengths.
KNOWING ITS ORIGINS
A robot’s origin position is a vital part of the set-up process because
it instructs the machine on what position it should return to when
it rests. The memory for where each axis should be is stored in the
robot battery. Without the position, every path trajectory will be off,
resulting in inaccurate actions that can damage equipment or even
hurt nearby workers.
If the battery fails mid-process, the operator must re-programme
the robot’s origin position before restarting the application.
Retraining can take a considerable amount of time to ensure all axes
are aligned correctly, resulting in further production downtime.
34
PECM Issue 35
To avoid the need for re-programming and retraining, operators
should ensure that the robot returns to its origin position when it
powers down. This means that should the battery fail during start
up, the robot is already in its origin position.
ADDRESSING POWER NEEDS
As robots become increasingly more intuitive, their power
demands also become significantly greater. To complete more
complex tasks robots may be fitted with an array of sensors to
detect variations in light, sound, temperature, and distance. Each
of these sensors places a greater demand on power, meaning a
more effective solution may be required.
When considering potential battery options for your robot, there
are several options available, however Li-Ion (lithium-ion battery),
Li-Poly (lithium polymer) and NiMH (nickel-metal hydride) are
normally considered to be the most suitable for robots with high
power requirements.
Ultralife Corporation has designed a range of primary, non-
rechargeable lithium thionyl chloride and lithium manganese
dioxide cells and batteries to provide further long-term power
solutions. As with all batteries, regular testing is vital to ensure they
do not die unexpectedly.
While industrial robots continue to improve productivity,
competitiveness and overall process automation, if they are
not supplied with adequate power manufacturers could face
additional problems. When a design engineer or systems
integrator begins work on a new robot project, he or she should
consider power supply at the outset, to ensure that the project
bears fruit in the way the end user would want.
www.ultralifecorporation.com