Add and Remove ChildViewController

childView.m

// add child view
UIViewController* controller = [self.storyboard instantiateViewControllerWithIdentifier:@"test"];
[self addChildViewController:controller];
controller.view.frame = CGRectMake(0, 44, 320, 320);
[self.view addSubview:controller.view];
[controller didMoveToParentViewController:self];

// remove child view
UIViewController *vc = [self.childViewControllers lastObject];
[vc willMoveToParentViewController:nil];
[vc.view removeFromSuperview];
[vc removeFromParentViewController];