As stated earlier in this thread, we do not officially support controllers on PC... however...
If you launch brink through steam with the following launch option (Right click Brink, then Properties\General\Set Launch Options):
+set g_EnablePCControllerInput 1
This will enable the detection of controller devices. As this is an unsupported feature, there are a few things you should be aware of:
1) You will need to create a config to bind the controller inputs to game actions
2) We have only ever used the xbox360 controller this way internally
3) There is no aim-assist in the PC version of the game
I hope this helps!