Fructose is the sugar you get from fruit and this what honey is made of (from flowers). Fructose is an GI stimulant. High-fructose corn syrup is the "baddie" for IBS. As you've read, honey is okay in SMALL amounts.
Sucrose is what people think of as "normal" sugar. This comes from sugar cane and beet. This is usually fine for IBS.
Glucose is one of the most basic forms of sugar. In chemical terms, its the smallest sugar molecule. This should be fine for IBS. Your body breaks all carbohydrates down into glucose to absorb the energy, which is why high energy drinks (like Lucozade) are made from glucose.