nlgamlss
(Package: gamlss.nl) :
Fitting non linear Generalized Additive Models for Location Scale and Shape (GAMLSS)
This function is an additional method for fitting GAMLSS models. It suitable to fit linear or non linear parametric models using distributions available in the GAMLSS package. It is based on the function stablereg() of the R package stable created by Philippe Lambert and Jim Lindsey which can be found in Jim Lindsey's web page http://popgen.unimaas.nl/~jlindsey/index.html (see also Lambert, P. and Lindsey, J.K. (1999)). The method is very general but requires starting values for all the parameters. For parametric models it can also be used to give the exact (that is taking into the account the correlation between the distributional parameters) asymptotic standard errors.
nl
(Package: gamlss.nl) :
Functions to fit nonlinear additive models in GAMLSS
The function nl.obs generate a nonlinear object which can be used to fit a nonlinear additive model within the gamlss algorithm. The function nl takes the nonlinear object created by nl.obs and returns it with several attributes which are used in the function gamlss.nl() which is doing the actual fitting within the backfitting function additive.fit. The actual fit is done by the R function nlm. The function gamlss.nl() is never used on its own).
NL.control
(Package: gamlss.nl) :
Auxiliary for Controlling non linear GAMLSS Fitting
This ia an auxiliary function used to control the iterations for nlgamlss fitting. Typically only used when calling nlgamlss function with the option control. Since the nlgamlss uses nlm for fitting all of the NL.control argument are passed to nlm.
gamlss-nl-package
(Package: gamlss.nl) :
The GAMLSS add on package for fiting parametric non linear models
The main purpose of this package is to allow non-linear fitting within a GAMLSS model. The main function nlgamlss() can fit any parametric (up to four distribution parameters) GAMLSS family of distributions.
providing 
.