I live in area where it's this hard clay. The lawn is hard clay some...
Somehow your question has found its way to Ask an Expert in Oregon. We do, in some areas, share the same problems that you have experienced: weed growth, hardpan under heavy clay, etc. However, our climates are not especially similar, so we can give you some general information and a source of Michigan information which will set you on the right track.
First of all, summer is a lousy time to start a lawn. So you should spend the summer months preparing the ground and then, come September, you can start seeding. Using sod can be a good choice for you, as well.
Soil prep is going to involve getting rid of all unwanted vegetation. Best not to use weed killers. You can scrape off the weed growth, core aerate (with a machine) the ground, and/or solarize the soil. Solarizing involves scraping or tilling, watering, then covering the area with translucent plastic (not black) and letting the sun "cook" the weeds. It will take 6 to 8 weeks for a complete kill. Any weeds that survive such as perennial weeds can then be removed by hand.
Depending on your soil situation, you may need to add organic materials
Your second question to answer is what grass seed or sod shall I use? Tall fescues (there are several on the market, including a new LS strain, which is laterally spreading and makes a thick green cover) are deep rooted. They do need regular water, which should not be a problem because you have sprinklers. Tall Fescue is winter-hardy in Oregon in regions where there is little or no snow, but can be cold (25 degrees or so). Your best bet is to get information on the kind of seeds that work best in your area by checking out the many lawn and turf articles available from Michigan State U's Extension Service. One is titled "Six Steps to Fall Turfgrass Establishment". The MSU Extension website can be accessed at www.canr.MSU.edu We hope this gives you some help with the task ahead.