Robotic arm design project

Hi everyone,

For my project I am designing a robotic arm. I intend to fix this arm on the top of a pioneer 3dx robot later on.
Following are the details of the motor and motor shield I will be using for my project :

Motors details:

  1. http://www.andymark.com/product-p/am-2971.htm (12v 22 amp stall current 16 ft-lbs torque)

  2. (2 of these) Pololu - 131:1 Metal Gearmotor 37Dx57L mm 12V with 64 CPR Encoder (No End Cap) (12v 5 amp stall current 18 Kg.cm torque)

Motor shield deatils: (I have the following motor shield as it is compatible with arduino)

• Low-cost robust H-bridge ''shield'' for Arduino
• Provides the ability to control up to 30A of current at up to 28V
• Supply voltage: 5V to 28V (24V max battery rating)
• Continuous output current: 13A

I am considering to use a battery to power the system.

I thought of going for 12v 22 Ah battery but its too heavy to be carried along the mobile base.

Then I thought of using pioneer 3 dx robot's battery to power my manipulator. Rating are 12v 7.5 Ah.
But again I am confused whether to go for it or not since one of the motor will be drawing currents at around 15 amps of current . should I go for it ?? will it work?

That's a lot of current! What are you planning on having the arms move with all that power?

I am designing it for my lab,to move equipment around. Weight of the equipment can vary between 500g to 1 kg.

1kg ~ 2.2lb. That doesn't sound too heavy, but I wouldn't want it dropped on my foot 8)
No experience with moving stuff myself. What's at the end of the arm for grippers or a clamp around a jar neck or similar?