DEWBOT V Electrical
Electrical and Electronic components are a the second part of the robot triad (mechanical, electrical, programming). From early in the design process we knew that the space for the electronics would be limited.
As with the bumpers, the key design goal of the battery box is quick and easy access. The battery box is a combination of metal and Tuffak . It is set into the frame at a 60 degree angle. The tight fit and gravity holds the battery in place. We use Anderson PowerPole electrical connectors. Matt currently holds the battery change record at 11 seconds.
The main power switch is located next to the battery. It is fully accessible, but is protected by the frame. Power is routed into the robot to the Power Distribution board.
Jaguar Support Panels There are six Jaguars in the system:
- 2 Left / Right Motors
- 1 “Seventh” Wheel
- 1 Beater Bar
- 1 Spindle
- 1 Hopper Rotation
The six Jaguars are mounted behind the drive wheels on the inside of the robot. This space was chosen:
- Close proximity to the motors
- Opens up space in the interior of the robot
They are mounted on Tuffak panels using tapped pop rivets. The mounting system means that we only need access to one side there are no nuts to hold. Curved Tuffak parts that make up the lower ball scoop to protect the Jaguars from damage.
Central Electronics Support Panel
A central Tuffak panel is mounted across the robot frame. It attached to the frame both top and bottom for support. The panel has these items mounted on it:
- Power distribution
- Digital Side Car
- Lower Signal Connection Panel
- Two Spikes
On the other side the cRio is mounted. The location of the cRIO is in the central core where it is well protected against any damage. On the other hand it is easily accessible from the top of the robot to allow tethering and manual resets. If necessary the A/D or Digital boards can be replaced in just a few moment.
In general the wiring space is very tight. Boards are close to minimize the amount of wiring needed. Each cable is routed in a set pattern to keep them out of the path of the mechanical systems. Ties are placed every 3 inches to keep everything in place. Each end of each cable is labeled and numbered.
There are a number of cables that run up the central spindle for the electronics at the top. The wires terminate in a 15pin D connector. This connector is mated to a custom connection panel that accepts pin connectors (standard PWM connector / cable) for further connections to the Digital Side Car, etc. Wires in the spindles are color coded so we don’t need to worry about marking them.
There is also a 1Amp fuse on the board to protect the camera at the top of the robot.
On-board robot control panel
Near the power switch is a Tuffak panel that contains three switches. These switches are used to control the autonomous driving speed, the direction that the robot will turn during autonomous and the spin factor. By being able to set these values on the floor the Game Strategy Team can make last moment changes.
The panel is also serves as the mount point for the wireless access point. It is designed to have the status LED’s readable by the team. This allows the team to verify that the connection path to the field control is working. The corner location is also away from most metal components this should improve radio reception. The Ethernet connection is accessible; we can also use this as a tethering point.
At the top of the robot there is wiring for the Orbit Ball shooter, power and data connections for the camera, a ball sense switch that indicates when a ball in ready to fire. Finally there is a connection for the heads-up display.
There are two 24” long LED strips that wrap around the robot. When the ball is in the fire position the lights activate. When the camera system locks onto the target, the LED’s flash. This lets the drive team know when to fire without taking their eyes off the robot.
There are a number of different sensors in use on the robot.
Pressure sensor is mounted in the compressor air stream to control the on/off activity of the compressor.
Rotational Sensors are mounted on each of the transmissions. This allows tracking of the speed of the wheels. The sensors are the primary input to the traction control software.
A potentiometer is mounted at the base of the spindle; it gives position location of the shooter. It is a Vex pot, it comes pre-wired, and the 10K ohm linear range makes it easy to use. While they only have a 270-degree read area, they can not be damaged by continuous rotation.
A micro-switch with a plastic extension arm is mounted at the top of the robot. It senses when a ball is in position and can be fired.
Finally the camera is mounted on top of the shooter and is used to find the targets.