When I was first introduced to programming the teacher made it a point to explain that no one has ever learned to program by reading books or solutions. You have to do it yourself.
Now, I do understand where you're at since I too have zero imagination for these things, but do have some examples you can take to get started.
Here's some ideas and tips for you to program:
- Set of traffic lights. However, program them so that the time a certain direction is green can be configured and modified. Don't forget to check for feedback on the lights to ensure that they're working and if not raise the relevant faults.
- Car wash system. Don't waste a lot of time with motion control as it's not easily simulated, but program a car wash with the ability to choose certain options as well.
- Industrial Jam making system. This is a big one and you need to take it in a structured approach. So start off creating logic to control and alarm process devices like valves motors, VFDs, proportional valves, etc... you can also use a platform like PlantPAX if it's useful for your career.
In this system you have say... 3 jams that can be made and you have to dose the ingredients into the mixer, so think water, sugar, fruit (this will be a solid so you'll need a hopper and screw conveyor), additives, along with an agitator and heating controls. (You can look up a jam recipe online and replicate it). As I mentioned above, do this by blocks. Start with process devices, then create a sequence/routine/function to dose each ingredient (bonus points if the function is the same for all dosing) and finally create your recipe sequence. In addition, create simulation logic to run alongside your program (this is easier with PlantPAX) so that you can see your logic running without you having to be simulating inputs.
The other aspect of this is to know safeguards to be put in place and alarms that are useful, common, but that would be a longwinded post that I don't have time for now, but you should still think and ask what if this or that goes wrong and how to get around it. I'm sure many of us here would be happy to give you ideas ONCE you ran these scenarios yourself and came up with something.