For some reason, sci-fi writers have an obsession with robots that are little more than flawed, tin-can, replacement humans. Maybe that makes for a better story, but it doesn't really reflect the current state of robot technology, with its emphasis on developing practical robots that can work alongside humans.
Following your exercise session, rest your bruised knee while applying ice. After the first day of injury to your knee, you should apply ice for 10 to 15 minutes, four times per day. On the first day, you can apply ice for 15 minutes of every hour.
It took me about 2 weeks. I only took 2 or so days off. I made sure to run on level surfaces, I used one of the neoprene knee bands, I iced and I borrowed my friend's foam roller and used it several times a day for about a week. Do that and you should be good to go.