you need calibrate the torsional spring constant which is nontrivial, there are few refs in the literature.

Determination of the adhesion force is quite easy. You need to multiply the deflection (vertical, not lateral!) by the spring constant of the cantilever.

Determination of the lateral (friction) force is more difficult. Usually you don't know the torsional spring constant, therefore I suggest to use a reference method. One of such approaches is described in the following paper: Kulik et al.,  Beilstein J. Nanotechnol. 2015, 6, 1164–1175.

You could calculate adhesion forces from vertical deflection. First, you need to convert mV to Newton, and total deflection to cantilever deflection. Below is a nice summary explaining it:

http://cp.literature.agilent.com/litweb/pdf/5989-8215EN.pdf

In our article we also showed the adhesion forces calculated from converted force- distance curves:

http://www.sciencedirect.com/science/article/pii/S0266353816302330?via%3Dihub

I agree with the previous answers: vertical force measurements (force spectroscopy) is probably a more direct measurement, but the cited paper from Kulik et al. is also very interesting.

As you have all cantilever dimensions, you may try to calibrate the torsional spring constant using Saders method [N/m] (see link below). Still, you need to measure the lateral sensitivity [m/V]. This may be done by high resolution lateral force measurement at a steep edge. 

http://www.ampc.ms.unimelb.edu.au/afm/calibration.html

http://repository.upenn.edu/meam_papers/84

Thank you for your suggestions. I am going through the literature mentioned above and would get back soon. :)

Just one doubt, in my case there is no interaction between tip and the sample, so vertical deflection will not work in my case, or will it?

Thanks again. 

Dear Adhesion can be calculated directly by F-D curve and the pull-off force in retrace curve is actually adhesion work or force required to overcome that pull-off.

@Hussain Wajahat: thank you for the response. Will the pull off force still be valid in my case where there is no interaction between the tip and the surface?

Sankalp Verma Dear mostly Contact mode is used to find Adhesion. but I am not sure about non-contact interactions, maybe that case you can only consider Vander waals forces but you should check.

Thank you for the suggestion.

Ayse Cagil Kandemir Can I get a new link for converting mV to friction force(nN orN) similar to http://cp.literature.agilent.com/litweb/pdf/5989-8215EN.pdf. I am trying to move a pillar on a smooth surface to do superlubricity experiments with FFM/LFM. Also how to measure friction coefficient from the friction micrograph.