Hang from a chin bar and SLOWLY curl your knees up to your chest and try and touch the bar,or as close as you can,then SLOWLY,in a controlled negative lower them.Do not relax at the bottom keep them tight,and exhale on the way up.These are absolute murder if done correctly,but really hit the lower abs for me. If you do them right your hip joints should not be effected.The idea is to curl the pelvis toward the sternum,not just swing the legs at the hip.As for the love handles,that is just diet.It seems they are the last bit of fat to go.Be patient and do your cardio and diet and they will come off.
Another good one similar but not hanging [which I can't do for that long since I have trouble with pullups]-- for lower abs is to lay on your back and hold a light-to-med weighted bar (or plate) above you with straight arms--(I use about a 30 pound body bar). While keeping your back on the floor and arms and knees together locked bring your knees into your chest slowly, then do a reverse curl up, lifting your butt---and try to bring your toes/feet up over the bar. Tap your feet to the ground and repeat.
Alternate these with reaches up with legs extended, still holding bar, then do v-sit twists holding the bar in front of you (like a front squat).
This set is not that easy-- I do 30 reps of each x 2-3 sets and it will work the abs great!