UNH Combat Robot April 15-17, 2011

Drive System

The robot maneuvers with two drive wheels and tank style steering. NPC-T74 DC motors provide the drive power with 240 RPMs with 1480 ft-lb of torque. The 24 Volt motors are geared down at a 20:1 ratio and have a stall current 210 Amps. The speed is voltage regulated by Victor 885 electronic speed controllers. The speed controllers handle 120 A current continuously and surge currents of 200 A for 2 seconds and 300 A for 1 second, suitable for robot combat.

Victor 885 Speed ControllerNPC T-74 Drive Motor

Dual Rank Synchronization 8 Bit Counter4 Bit Comparator

Output Stage

5 Volt Battery

Solenoid

AR6110 Receiver

Pneumatic Weapon SystemInlet Pressure Gauge(1000 psi)

Outlet Pressure Gauge(200 psi)

Buffer Tank

48 cubic inch3000 psi HPA TankWith Pressure Gauge

Pressure Control

Down Stream Bleed/Safety

Control Circuit

Solenoid Valve

Pneumatic Cylinder

High Pressure Rubber Hose Rated for 300 psi

The main weapon system consists of a flipping arm controlled by a pneumatic piston. The flipping arm includes a wedge shape that rests directly on the ground in order to get underneath opponents and rotates about its fulcrum to 50° to flip them. The pneumatic cylinder is powered by HPA stored at 3000 psi and regulated down to 220 psi for competition. The air flow is controlled by a solenoid valve which fills and exhausts the cylinder. The cylinder generates over 1500 pounds of force, 1100 of which is vertical lift.

Frame & Armor

The frame is made up of 1” square steel tubing with a 1/8” wall. Steel was chosen because of its strength and durability and its ability to be welded easily. The bottom plate of armor on the robot is a 1/8” steel sheet, which was used as support and as a mounting aid. The front plate of armor is also 1/8” steel because the front is a high impact point. The rest of the robots armor is 1/8” aluminum. The aluminum was chosen in order to meet the weight requirement of 220 pounds. The final weight of the robot was 208 pounds.

Communication

The communication system includes all control elements between the transmitter and each operational part. A mated pair Spektrum transmitter and receiver were used to transmit signals. Two output signals corresponding to the joysticks were fed directly into the speed controllers to drive the motors. A third toggle output was used to control the solenoid, which controls the pneumatic flipping weapon. This output is a PWM signal that toggles between two duties. In order to interface to the solenoid, a circuit was designed that determines which duty cycle is on the output and uses a power transistor output stage to sink current through the solenoid to fire the weapon. A separate 5 volt battery was used to power the receiver and circuit to isolate noise from other batteries and systems.

Competition• Robogames 2011 in San Mateo, California

• Double elimination tournament with 3 minutes matches

Design Goals• Robust, while meeting 220 lb limit

• Fast movement and agility• Effective weapon able to flip comparable robots

Team Members: Michael Litchfield Nicholas Rivera Patrick Kerrigan John ColeAdvisor : Frank Hludik