Force X was the first featherweight robot to come out of Team Storm where we wanted to create something totally different from the other featherweights at the time which were all just simple lifters

What Team Storm created in Force I opened people's eyes as to what could be done with the featherweight class. 

 We found some 35w motors which we thought would do the job of driving a featherweight but first we had to test that theory so we quickly created a test chassis for them

You can see the test chassis running here and here.

Once we'd proved this concept we produced a scale chassis out of MDF for Force X.  Using 6mm MDF which was about £5 for a large sheet from B&Q.  We'd recommend using MDF to prototype robots as much as possible.  Once the test chassis was created out of MDF we strapped the key components to it to test.

Design and Build of Force X

We first

Force X was almost entirely modelled in MDF before going into final construction.  Here you can see the baseplate of Force X, the two motors, a Vantec to provide control and a gyro on the back.  This mock up was constructed to test the behaviour of a lightweight robot when controlled by a gyro.  Initial tests on the first test chassis hadn't gone well, and we were hoping that extra weight would make the gyro perform better - we were right.

Sometimes this is how it starts in roboteering, simple testing with parts strapped down to a piece of MDF with insulation tape.

Force X's Crushing Power

The actuator in Force X is rated to 500lbs of force at 12v, we over-run the actuator to 24v giving around 2000lbs of crush (just under 1 tonne).  However, the actuator has a clutch built into it which we can adjust allowing us to pre-set the amount of force produced - the limit is really the power of the motor, and once that stalls the actuator cannot produce any more force.  Under normal working to date, we have never even had the motor slow down - and havn't pushed Force X to its limits yet.

The video below gives you an idea of the speed of Force X's weapon, and the power.  You can easily stand on a drinks can, jumping on it will crush it, however it takes a lot to perfectly fold a can without it twisting to one side or the other.  In the video you will see that Force X is capable of delivering its crush stroke in 1 second from top to bottom.... the poor can under the jaw doesn't really stand a chance.  

Having a crushing weapon is one thing, but its useless if you don't have a weapon that you can apply as soon as you get your opponent in a position to apply it.  Force X certainly doesn't have that problem... as soon as you're under the claw....... squish !

A tour around Force X

1 - Bosch drive motor connected to 12mm axle carrying modified skateboard wheel.  Motor supports one side of the axle with sealed bearing carried in aluminium block supporting other side of axle.  Needs modification so that both sides of the axle are supported with bearings to take load off the motor.

2 - 4QD LED Battery meter - allows easy monitoring of battery voltage on board.  Nickel Metal Hydride batteries last a long time however they die very suddenly.  You can anticipate this cut off because the terminal voltage of the cells sags just before the end of their life - this can be spotted by the battery meter LED's dipping as you accelerate the machine.

3 - GT-H5 Speed controller (1 of).  A new speed controller developed by George Francis of Chaos 2 fame.  Force X is the first robot to use these controllers and has been testing the design.  A full H-Bridge with 4 Fets, failsafes, mixing (two boards talk to one another to mix) - and far more.  For full details visit the GT Electronics website from the links above.  Conservatley rated for 10amps, but clearly capable of much more !

4 - Fuse Block.  Yes Force X has fuses - designed as a general protection for the machine against shorts.  More about protecting the expensive batteries than the speed controllers against a dead short between two circuits.  Each drive motor has its own fuse, with plans to put a fuse in place on the weapon line as well.  The fourth fuse holder is empty and is where the 'spare' fuse is located.

5 - GT Electronics H5 Controller - the second speed controller for the other side of the drive - linked to the first via a serial cable to allow bi-directional communication for mixing and failsafes when running

6 - Team Delta RCE225 Dual Ended relay board.  2 Relays, with limit switches which drive the linear actuator on Force X.  It plugs straight into the reciever and takes power from the main 24v supply.  Inputs for 2 limit switches allow two microswitches located on the arm mechanism to prevent the actuator from moving beyond its limits of travel in the machine and thus destroying the machine.  At the top in the middle of the picture you can see some bent M6 studding - this is where the 'what happens if a microswitch should fail' testing was done - it simply bent the 6mm thick steel !

7 - Futaba 9 Channel Reciever

8 - GWS Gyro.  Not going to go into what a gyro does here, but suffice to say that Force X relies on its Gyro to be controllable.  Take the gyro out and it becomes a very difficult machine to drive indeed.

9 - Cooling fan - the motors that Force X use get very very hot when running.  The motors themselves have thermal cutouts built into them to prevent the motor from actually overheating, however the fans cooling the motors ensure that the motors never reach this temperature, and help to cool the motors down quickly in the pits after a fight.

10 - You can just make out the two 12v NiMH battery packs here laid side by side - one in the center of the robot alongside the actuator, the other in the right hand side section of the machine.  Each able to supply 3000mAh - they are roughly equivulant to carrying around 2 x 6Ah 12v SLA batteries !  Suffice to say Force X should win any endurance competition its entered into !

Drive System

The motors have a 4mm square hole through the end of the gearbox - we use 4mm key steel attached to our axle and wheel support to allow the motors to drive the wheels.

In the picture and diagrams above you can see where the 4mm shaft enters the gearbox of the motor, where it exits the motor it becomes as 12mm shaft with a large 'hub' on it where the nuts and bolts go through to attach the skateboard wheel to the shaft.  There is then a supporting bearing at the end of the axle sitting in an aluminum block which prevents the axle from flexing.  The whole thing was machined out of a single piece of steel down to the 12mm diameter leaving the 'hub' to attach the wheel to.  A hole was then drilled into the end of the axle and a square piece of 4mm key steel was inserted, and retained by grub screws.

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