Soft Robotics seems to be in-vogue right now. Perhaps you could use latex rubber glove fingers, with one end fastened around an air tube, or perhaps two fingers of different sizes together so that you can use differential forces to fold and unfold the fingers? Don’t know what an air pump and solenoid controlled valves cost, but perhaps using a SG90 solenoid to move stick inside a tube that exposes progressively more holes for the air to flow would be inexpensive to implement.
Just remember, engineering courses are learning experiences - you don’t have to solve world peace, or even succeed at your chosen task if you can explain what went wrong, why it went wrong, how you might have foreseen the problem, how you might do things differently if you ever need to try it again.