Is it possible to use a brushless DC motor as a generator? If we use the brushless DC motor in the following configuration, the brushless DC motor is used in front wheel of a rover/small car, and the power transmission is done by rear set of wheels, is it possible to recover energy from this configuration? Can we generate electricity from the DC motor in the following configuration?
You can't make something out of nothing.
Yes, you can "reclaim" energy from the front wheels while driving the back wheels. However, the energy that you remove through the front wheels has to come from somewhere, and that somewhere is the back wheels.
The driving energy will have to increase to compensate for the extra load of the power generating wheels.
Electric and hybrid cars already use a similar system to reclaim wasted energy used during braking (which would usually be dissipated as heat), and it's called Regenerative Braking