If your Android tablet has a Mini B receptacle, it is unlikely that it supports USB OTG. In the USB OTG specification (revision 1.3, from December 2006) they make it pretty clear in section 6.1 that a device that supports On-The-Go should have a Micro-AB connector. (Also, in section 3.10, they mandate that a device with a Micro-AB connector should support On-The-Go.)
I recommend looking for a tablet that supports OTG or using an Accessory Development Kit (ADK) board such as the Arduino ADK. The idea of the ADK is to have a microcontroller board that acts as a USB host so it can talk to an Android device that acts as the USB device.
Your question reminded me of this project, where someone used OTG on an Android phone to talk to a Maestro: