Run rosparam load in runtime?

edit

[UPDATED ANSWER]

Hello,

If you want to update the parameters in run-time, you should use the "dynamic reconfigure".

Basically, what you need is a parameter file, like below: <your_package>/cfg/MyParams.cfg

#!/usr/bin/env python
PACKAGE = 'my_dyn_rec'

from dynamic_reconfigure.parameter_generator_catkin import *

gen = ParameterGenerator()

#list of parameters
gen.add('int_param', int_t, 0, "description for the integer parameter", 50, 0, 100)
gen.add('str_param', str_t, 0, "description for the string parameter", "Hello world!")

exit(gen.generate(PACKAGE, "my_dyn_rec", "MyParams"))

The node you want to work with the parameters, here is an example: <your_package>/src/my_node.cpp

#include <ros/ros.h>

#include <dynamic_reconfigure/server.h>
#include <my_dyn_rec/MyParamsConfig.h>

void callback(my_dyn_rec::MyParamsConfig &config, uint32_t level) {
    ROS_INFO("New values: [%d] - [%s]", config.int_param, config.str_param.c_str());
}

int main(int argc, char **argv) {
    ros::init(argc, argv, "my_node");

    dynamic_reconfigure::Server<my_dyn_rec::MyParamsConfig> server;
    dynamic_reconfigure::Server<my_dyn_rec::MyParamsConfig>::Callback f;

    f = boost::bind(&callback, _1, _2);
    server.setCallback(f);

    ros::spin();

    return 0;
}

Finally, you CMakeLists.txt must be configured. For this example, this should be enough:

cmake_minimum_required(VERSION 2.8.3)
project(my_dyn_rec)

find_package(catkin REQUIRED COMPONENTS
  dynamic_reconfigure
  roscpp
  rospy
)

generate_dynamic_reconfigure_options(
  cfg/MyParams.cfg
)

include_directories(
  ${catkin_INCLUDE_DIRS}
)

add_executable(my_node src/my_node.cpp)

add_dependencies(my_node ${PROJECT_NAME}_gencfg)

target_link_libraries(my_node
  ${catkin_LIBRARIES}
)

You can follow some the tutorials below: ROS wiki oficial tutorial: http://wiki.ros.org/dynamic_reconfigu...

And a video I created: https://youtu.be/YKZkZSVcsnI