Differential Drive

What is differential drive ?

The differential drive is a two-wheeled drive system with independent actuators for each wheel. The name refers to the fact that the motion vector of the robot is the sum of the independent wheel motions. The drive wheels are usually placed on each side of the robot and toward the front.

This is a primary project which covers following concepts-

1.Power Supply (Adapter or Rectifier)or 12v battery

2.Three way switch operation.

3.DC Geared Motors

4.Basic motion of Robot

Components Required

1. Soldering Iron
2. Soldering Wire
3. Wire Stripper
4. Single strand wires
5. Multi strand wire of appropriate length
6. PCB (dot)(optional if using adapter)
7. 4 Diodes (D1N4007)(optional if using adapter)
8. 1 Electrolytic Capacitor (1000 micro-farad)
9. Step down Transformer (220v- 12V AC)
10. Two 3 way switches or Two 2 way switches and two push button switches.
11. 2 plastic boxes to encase transformer and for control box
12. Plug for transformer(optional if using adapter)
13. 2 pin, 4 pin relimates
14. Insulation Tape
15. IC 7805(optional if using adapter)
16. DC motors
17. Breadboard (optional)
18. Multi-meter

Chassis

Chassis is a mechanical assembly for making a 4 wheel drive platform.Where you can mount any controller board to drive your bot. This is just the mechanical chassis, Optionally as shown in the figure you can use 4 DC geared motors, 1 castor and 4 wheels with rubber rings so you can make both variants .

Mechanical Assembly

TYPES OF WHEELS:

Step 1 : Fit the caster wheel at position show in above diagram with 1.5–2 inches (approx.) screw. Fit the dc motor into the holes of chassis and couple the wheel by using screw or rubber tube.

Three way switch circuit :

Step 2 : Make three way switch circuit using DPDT as shown in the figure below.

Step 3 : Connect wires to each motor as shown in the figure below.

Robot with 2 wheels attached to two motors and one castor wheel.

Robot with 4 wheels attached to 4 motors.

Step 4: Connect the wires of the motors to the three way switch .

Your robot is ready !!

Here is a video which shows the motion of a differential drive robot .