do. It powered through every obstacle.
One of the things I was impressed with was how nicely
it crawled over irregularities and obstacles on the path.
There were places on the trails with small step downs and
countless exposed root systems making the path fairly
traitorous for a small wheeled bot. The Mantis drove over
them smoothly and effortlessly.
After the tests, I took the Mantis with me to the next
Robot Group meeting here in Austin, TX. I wanted to show
off this latest project and get some of their impressions.
The robot caused a lot of excitement in the group. There
were some questions about how it worked, how it was
controlled, the effectiveness of the motors and wheels,
etc. — all of which I was more than happy to answer.
There were some suggestions for using the camera and
how to improve the suspension. In particular, one of our
members suggested doubling the spring shocks, moving the
shocks inside the struts, and replacing the screw offsets
with a solid bar to provide some additional strength to
these stress points. These were solid suggestions which I
will look at for aesthetics if nothing else — especially since I
experienced none of the issues these changes are intended
to address. Save one.
There was a tremendous dust build-up at the joint
where the suspension is attached to the frame. This caused
that joint to seize up and the wheel would no longer move
up and down. The solution is remarkably simple, however.
Since the screw that is acting as the pivot point is held
on by an aero-nut, simply loosening this nut by a quarter
turn should allow enough play for the dust to not collect.
So, this is a fix I’ve implemented with good results.
The new Mantis chassis is a very capable platform for
your next rover style robot project. The six-wheel design
and independent suspension makes for a versatile vehicle
on-road and even more so off-road. The only drawback I
see with the chassis is no clear method for mounting
electronics, but, that is what a chassis is all about: a
platform on which to build. The Actobotics system provides
ample mounting opportunities for adding either more
Actobotics parts or your own custom supports and frame.
Like all of the robot chassis provided by ServoCity, you
will want to add to the kit and likely make some
modifications to suit your needs. I will be ordering some
more parts from the Actobotics line to build it out a little
more, and to implement some of the suggestions made by
A little more play will be introduced to the bolts
holding the suspension to the frame in order to reduce dust
build-up and the resulting stiffness at the joints. I’ll probably
double up on the springs to increase the payload
capabilities, and move the springs inside the suspension
arms. I’ll be using more channel or custom brackets to
mount a platform or box on top.
In short, ServoCity has done it again with a durable,
adaptable, and fun robot chassis in the Mantis. SV
Mantis tackled most terrain with little effort — especially areas
like these exposed roots on the trail.
SERVO 11.2015 59
The Mantis proved indomitable on and off the trail.
Mantis cruising along a trail at Walnut Creek Park in Austin, TX.