RQGIS doest not work on both of my personal and work computer

[Epsonscandu37]

Hello i would really like to use RQGIS instead of python to make shiny app that use QGIS, i can't make the first command work. Can you help me ?

> find_algorithms(search_term = "centroid.+(qgis:|saga:)")
Error in py_run_string_impl(code, local, convert) : 
  NameError: name 'processing' is not defined

> py_config()
python:         C:/OSGeo4W64/bin/python.exe
libpython:      C:/OSGeo4W64/bin/python27.dll
pythonhome:     C:\OSGeo4W64\apps\Python27
version:        2.7.14 (v2.7.14:84471935ed, Sep 16 2017, 20:25:58) [MSC v.1500 64 bit (AMD64)]
Architecture:   64bit
numpy:          C:\OSGeo4W64\apps\Python27\lib\site-packages\numpy
numpy_version:  1.16.3

NOTE: Python version was forced by use_python function

and

> set_env()
$root
[1] "C:/OSGeo4W64"

$qgis_prefix_path
[1] "C:/OSGeo4W64/apps/qgis"

$python_plugins
[1] "C:/OSGeo4W64/apps/qgis/python/plugins"