Being a Project Manager, one of the standard statements are "PLAN THE WORK THEN WORK THE PLAN". In other words, if you are able to plan out the work that needs to be done, then you will have the project well under control as you work through the plan and complete the project. Many times projects will fail because they leader did not plan the work that needed to be done.
Planning and controlling are two important management functions. Planning is defined as a management process that concerns setting goals, developing strategies, and outlining tasks for the accomplishment of these goals. Whereas controlling is basically exercising influence or control to manage resources for the accomplishment of the set goals. They are related in a way that the controlling function determines the set procedures for the accomplishment of the goals determined during the planning phase. In fact the controlling function governs the overall management process. As it is done in all 4 phases of the management function such as Planning, Leading etc.