final competition - university of california, san diegocseweb.ucsd.edu/~yuc007/documents/vex/final...

Final Competition

Group B

22rd, May, 2007

Outline

• Competition Rules

• Expected Performance

• Strategy

• Mechanic Design

• Program

Competition Rules

Blocks

3 minutesAuto

Restart

Collide Main Role

Make full use of these

Expected Performance

• Improve the latency: reduce the time for taking

each block;

• Improve the throughput : increase the capacity

of blocks;

• Design several strategies to make choice

when collision and restart occurs;

• Improve the accuracy of turn and avoid using

parameters: make use of sensors.

Original Strategy

Different routes: left, mid, right routes;

Foresee whether the block is still there and

change strategy dynamically;

Calculate the points machine got and make

decision;

Try to go straight to save time.

Practical Strategy

Different routes: left, mid, right routes;

Set restart route and scan route;

Improve the ability of follow line even for some

extreme situations which will reduce the speed;

Consider the placement of blocks;

Give up the use of ultrasonic sensor since the

field is small and no need of dynamic strategy.

Mechanic Design

• Simply with efficient performance;

• Sensor: 3+2;

• Wheels: gear choice, two wheels;

• Arms: gear choice;

• Bumper Switch;

• Fencing structure: dimension, fence the blocks

inside.

Sensor Placement

Closing the sensors will increase the sensitivity!

Front Detection

Relativity of Sensors and

Wheels

Distance

between

sensors and

wheels

should be big

enough for

sensitivity.

Gear Choice of Back

Wheels

3:2 Gear Choice

based on the

required speed of

wheels

Motor

Front Wheels

Using

flexible front

wheels to

reduce the

error of turn!

Gear Choice of Front Arm

Servo

1:1 Gear Choice

based on the

range of Servo

Gear Choice of Back Arm

Servo

2:1 Gear Choice

based on the

range of Servo

Bumper Switch

Four

Selective

Choices for

different

strategies

and restart

Fencing Structure

Keep the

blocks inside

Depth 220mm

With the arm,

expected

performance:

three blocks

Width 140mm

large enough for

the dimension of

block

Program

• Follow Line (3 trace sensors);

• Turn Left and Right (2 detective sensors );

• Game Field Map (x,y,dx,dy);

• Execute the arms work

Follow Line and Turn

Front Detection

Line Tracer

Build Field Map in Program

X

Y

(0,0) (1,0) (2,0)(-1,0)(-2,0)

(1,0)

(2,0)

(3,0)

(4,0)

(5,0)

Arm Works and the

Placement of Blocks

Expected Performance

• Improve the latency: fast to take blocks;

• Improve the throughput : maximum four blocks;

• Design several strategies to make choice

when collision and restart occurs;

• Improve the accuracy of turn and avoid using

parameters: make use of sensors.

Final Competition

Appreciate the Study of

VEX in ENGG395E