How to use nested routes with several parameters in ember 2.17

I am trying to build an smarthome app and I am stuck with calling nested routes with serveral parameters. I want to show an information which user is logged in and below that template which is in my parent route i want to render child pages for showing households. After a specific household is chosen, i want to show the rooms in the household and then devices. This is my router.js

    Router.map(function() {
      this.route('about');
      this.route('users', function() {
      });
      this.route('households', { path: '/:user_id' }, function() {
        this.route('index', { path: '/:user_id' })
        this.route('rooms',{ path: '/:household_id' });
        this.route('devices', { path: '/:room_id' });
      });
    });

export default Router;

I link to households like this

  <h3></h3>

and now I want to declare a model in the route of households.js which returns an user from the ember data store and render the parent template. Afterwards the model should redirect to households.index with the user.id too and the households.index.hbs should render all households below the parent template. My households.js route looks like this:

export default Route.extend({
  model(params){
    {
      return this.get('store').findRecord('user', params.user_id);
    }
  }
});

and my household.index route like this

export default Route.extend({
    model(params) {
       return this.get('store').findAll('household').then(results => results.filter((site) => {
           return site.get('member').filter(x => x == params.user_id).length > 0;
       }));
      }
});

Actually the following error occurs:

Error: Assertion Failed: You attempted to define a but did not pass the parameters required for generating its dynamic segments. You must provide param user_id to generate.

In general I need serveral parameters in all nested routes/subroutes, because I need the user_id for example in the route devices for checking if the calling user is a admin. If he is an admin he would be able to add and edit devices. And i need the room_id to show only devices which are in the chosen room.

Is there any way to pass serveral parameters or using the controllers in a way, I can handle my purpose?