January 2019 – Hellfire Labs

Huntsman weapon test

Huntsman took its first trip outside to have its weapon tested. The electronics have not been formally mounted in the robot as this was a test of the motors and weapon drive train. There was some damage to the rear of the chassis at the limit switch while testing the axe return. The power of the return swing will be limited once the robot is complete but not at this stage.

This first test went well and everything is looking good. Not sure where the lizard ended up though.

Huntsman outside ready to have his weapon tested
Externally mounted VESC for testing
Completed weapon drive train ready for testing
This little guy came along for the ride when testing Huntsmans’ new axe
Damage to the limit switch
Huntsman upside down while testing the axe
Results of hitting a brick with Huntsmans’ weapon
The results of the first test of Huntsman’s axe
Beauty shot of Huntsman while testing the weapon

First test of the weapon.

Second test of the weapon with return swing.

Third test against a brick.

Welding Huntsman Part 2

The front armor has now been welded as well as welding the weapon hub assembly. The weapon and drive axles have been fitted. The axles are M30 bolts which are rated to a shear load of 337kN. This should make finding replacement axles in another country easy as they are off the shelf parts.

Welding the underside of Huntsmans’ chassis
Drive axle test fitting
Weapon axle test fitting
Boring out the center of the weapon sprockets
Ready to weld the spacer onto the sprocket
Each sprocket is welded to a spacer on either side of the axe
Welding the weapon hub assembly
The axe and hub assembly welded together

Welding Huntsman Part 1

Now that the steel has been cut the welding can begin. The welding is done from the centre out starting with the weapon supports. All the axles and drive are test fitted between welds to ensure that the chassis is not warping. This also gives an opportunity to cut the chain to the correct lengths and measure the spaces for the axles.

Axe bearing supports welded
Welding axe bearing supports
Welding the first bracket onto the chassis base
Welding the upright frame onto the chassis base
The axes rear limit switch
Top view of the axe rear limit switch
Another view of Huntsmans axe rear limit switch
Fitting the first stage of the axe chain drive
Fitting the chain to the first stage of the axes chain drive
Second stage of the weapon chain drive installed
Test fitting Huntsmans axe and weapon drive at the end of the first day of welding
Front armour and side frame ready for welding

Steel has arrived!

The water-jet cut steel has arrived for Huntsman. The steel is a mix of 3mm mild steel sheet and 6mm AR450 plate. The goal is to get the welding done before the holidays finish next week.

All the new steel laid out on the workshop floor
The axe with banana for scale
Test assembling the chassis
The chassis minus the armour

To begin with the sprockets have been welded together.

The sprockets for the weapon drive
A pair of sprockets ready for welding
Welded sprockets

All the parts have also been checked to see if the completed robot will be under the weight limit. So far 98.5kg.

Also some new weapons for ant-weights were added to the order.

Brushless motor sensor issues

Testing is underway on Huntsmans Kun Ray 2000w 48V electric scooter brushless motors. The motors are planned to be run off of a 12S LiPol battery via Turnigy SK8 VESC motor controllers but there seems to be and issue with the motors sensors. The available documentation for the motors and ESC don’t seem to match as the ESC will not work in sensored mode but the motor runs fine sensorless.

The endcap of the motor was removed and the wiring inspected and everything looks fine. It is difficult to reverse engineer the the sensor wiring entirely as the sensors are glued firmly between the poles and it isn’t possible to determine the exact part number of the sensor. It doesn’t matter a whole lot as our past experience with brushless motors low speed accuracy isn’t a priority. As long as the motors start under load and reach top speed quickly the sensors are not needed.They would be nice though.

In other news the drive train has been measured and the CAD completed. The steel order has been placed with the water-jet cutters and the steel should arrive soon.

Kun Ray motor with end-cap removed
Position of hall effect sensor with insulation
Wiring of the motor
Wiring the motors sensors to the ESC
Sprockets for the weapon drive train
Weapon drive train laid out
Weapon and drive motors laid out with the batteries

Huntsmans motors and drive arrive

Huntsmans’ motors, drive train chain and sprockets have arrived and the wheels. Now the dimensions of all the parts can be confirmed and the design finalised. Once that is done the design can be sent to the waterjet cutters so the steel can be cut.

The motors are 48V 2000W Brushless scooter motors which will be run via Turnigy SK8 VESC controllers.