I used to have hell getting ds1 to do his homework, they have a ridiculous amount. Reading every night, spellings, times tables, literacy and numeracy and they have asked me to work on a touch typing programme at home with him a few times a week as well.
He is in the top groups for everything, but struggles with writing and presentation, so when they give him four sides of A4 with measuring and shape drawing or complex calculations its not only difficult, it knocks his self confidence.
It makes me so mad. Exactly when are they supposed to find time to 'come down' after school, relax and just be children? Let alone find time to work on his core strength, do pilates etc. Then they tell me that he needs to join more after school clubs to help his social skills (he already does chess club and did do Judo till they stopped it). 
Ds2 has had the same amount as ds1 since Year 1! (Ds1 didn't start getting literacy, numeracy or times tables until Year2).
Ds1 is now ok-ish with doing his homework. There is always a tantrum, but at least it doesn't run into a meltdown these days.
We have a set timetable for after school, as it was the only way to avoid the daily meltdows. I hate being that restricted every day, but we don't really have a choice. I refuse to make them do homework at the weekends, as ds1 really couldn't handle the concept of doing schoolwork during his 'home time' at the weekend and on Fridays its reading and typing only (he loves doing both of those so they aren't a chore for him).
I have the timetable stuck up in the kitchen, on the front door and on the front cover of his home school diary and I remind him to look at it and what he has to do in the morning and before we leave the playground when I pick him up. That way he's expecting it before we get home.
After school timetable goes:
1.Come in, shoes in the basket, coats and bags on the peg, lunch boxes by the sink.
- Go upstairs, change into PJs comfy clothes.
- Come back downstairs for a drink, snack and a quick trip to the toilet.
- Stay at the kitchen table for homework.
- 10 minutes pilates exercises.
- Once homework and pilates are done they can do whatever they want until tea is ready. Ds1 ALWAYS has his Nintendo hour straight away.
We're told no more than 40 minutes on each topic. I used to make him complete it, as I was worried he would get into trouble if he didn't, but now he times it himself and when he's done 40 minutes we stop and I write a note in his book. This has made a big difference, as knowing he just has to do his best for a finite amount of time, rather than having to finish it at any cost really takes the pressure off.
I have to sit with him the whole time and he needs constant prompting and reminders to get it done. Its significant to note that he produces lovely work at home, but terrible and usually incomplete classwork. (I shall be pointing this out to them at his IEP review next week as evidence that he needs 1-2-1 support to fulfil his potential.)
I also have to help ds2 with his homework at the same time, although have tried to schedule them so that one is doing something like spellings while the other is doing literacy or numeracy.
To be honest, it makes all of our lives a misery and eats up our afternoons/evenings. I used to really look forward to my boys coming home from school, but now its just one long horrible grind of homework.
