Preheat a grill to high. Toss the eggplants, zucchini and tomatoes with 1 tablespoon olive oil; season with salt and pepper. Place the vegetables cut-side down on the grill along with the sausages. Cook, turning occasionally, until the vegetables are tender and the sausages are cooked through, about 4 minutes for the tomatoes and 10 to 12 minutes for the sausages and remaining vegetables. Transfer to a cutting board and let cool slightly.
Meanwhile, bring a large pot of salted water to a boil. Add the pasta and cook as the label directs. Reserve 1 cup cooking water, then drain the pasta.
Combine the basil, mint, garlic and the remaining 2 tablespoons olive oil in a large bowl. Chop the vegetables and sausages and add to the bowl. Add the pasta and 1/2 cup of the reserved cooking water and toss to combine, adding more cooking water as needed to loosen. Top each serving of pasta with the ricotta. Season with salt and pepper.