3D positioning system

[eextreme]

We are planning to design a device to test another device. The device being tested is stationary but the orientation of it varies (depending on how it is placed on the tester). In this design what would be better to use? A robotic arm or is there something else that can be used to move it in three directions?

[Soeren]

We are planning to design a device to test another device. The device being tested is stationary but the orientation of it varies (depending on how it is placed on the tester). In this design what would be better to use? A robotic arm or is there something else that can be used to move it in three directions?

Hard to say when you're being so cryptic about what you're trying to accomplish.
The solutions will obviously be different if the device (not the other device) is the size and weight of a game dice or the size and weight of a truck.
 

[eextreme]

small device the size of about a graphic calculator (and smaller)