To make your quadruped walk, you first need to connect the servo motor controller to the servos.The servo controller you are going to use for this project is a simple servo motor controller utilizing USB from Pololu (Pololu item #: 1354 available at www.pololu.com) that can control 18 servo motors. Here is an image of the unit:
Make sure you order the assembled version. This piece of hardware will turn USB commands from the Galileo into signals that control your servo motors. Pololu makes a number of different versions of this controller, each able to control a certain number of servos. In this case, you might want to choose the 18 servo version so you can control all 12 servos with one controller and also add an additional servo to control the direction of a camera or sensor. You could also choose the 12-servo version. One advantage of the 18-servo controller is the ease of connecting power to the unit via screw type connectors.
There are two connections you'll need to make to the servo controller to get started; the first to the servo motors, and the second to a battery.
First, connect the servos to the controller. In order to be consistent, let's connect your 12 servos to the connections marked zero through 11 on the controller using this configuration:
|
Servo Connector |
Servo |
|---|---|
|
0 |
Right Front Lower Leg |
|
1 |
Right Front Middle Leg |
|
2 |
Right Front Upper Leg |
|
3 |
Right Rear Lower Leg |
|
4 |
Right Rear Middle Leg |
|
5 |
Right Rear Upper Leg |
|
6 |
Left Front Lower Leg |
|
7 |
Left Front Middle Leg |
|
8 |
Left Front Upper Leg |
|
9 |
Left Rear Lower Leg |
|
10 |
Left Rear Middle Leg |
|
11 |
Left Rear Upper Leg |
Here is a picture of the back of the controller; this will tell us where to connect our servos:
Now you need to connect the servo motor controller to your battery. For this project, you can use a 2S RC LiPo battery, it will supply the 7.4 volts and the current needed by your servos, which can be in the order of 2 Amps. Here is a picture:
This battery will come with two connectors, one with larger-gauge wires for normal usage and a smaller connector for connecting to the battery recharger. You can use the XT60 Connector Pairs, solder some wires to the mating connector of the battery, and then insert the bare end of the wires into the servo controller.
Your system is now functional. Now you'll connect the motor controller to your personal computer to check to see if you can communicate with it. To do this, connect a mini USB cable between the servo controller and your personal computer.