How do I keep my Robot from going through the ground when he jumps?

I just noticed when rendering my animation, my robot is going through the ground when he jumps. I went back to the action and noticed a little dip below the ground when when he begins the jump, but in the animation he’s several inches below the plane. There’s no problem in the rest of the animation that I could see. Can someone tell me how to fix this? As I am a beginner, I only did a couple of tutorials on passive and active objects and physics, so I don’t know what I should do.

Blend file:

add a floor constraint to the foot bone.
or if the foot bone center is off the floor (i.e in the middle of the foot) then it may still sink a little so parent a new bone to the foot, bring it level to the floor and add the flor constraint to the new bone. make the floor the target obviously
and repeat for the other foot

Thanks for responding. I don’t know how to do that (although I did try). I then tried to make another jump action, but now the floor is following the robot when he jumps. I’ll try again tomorrow. I had trouble with the floor before and it was because I was using a different armature, which I never deleted. But since I have deleted the other armature, I am wondering why I am now having the problem with the jump.

The sequence where heel bone falls through the floor is located in-between key frames. Blender is just doing its own thing between frames there. So create key frame when heel hits the floor where you want the heel to be. Tell it what to do.

hmm yeah check your keyframes like ridix says, the floor constraint shouldn’t make the floor follow your model so something else is obviously going on there, i havnt actually looked at the blend you provided as my blender is currntly busy rendering and ihave no spare processors, so if i get chance i’ll look at it properly tomorrow

I am still having trouble creating another jump action. I added actions in this animation already, and I can’t figure out what I am doing wrong this time. I am able to add an action which I already used, but I want to add a new action. And I want it to be a jump action. It’s got to be something simple that I’m not getting. Can someone tell me what I am doing wrong?

This is what happens when I start to make a new jump action:

This is one of my many (failing) attempts to import a jump action from another blend file. (I think I moved the origin point of the robot to the plane.)

This is adding an action I already made and used. No problem with this action. Which makes my problem even more frustrating.

Blend file:

if you have imported an action from a different file and its not working, then go into the action editor and take a look at it from there. moving things like origin points or just adding more geometry to the model you’re trying to apply the action to, can create issues that may be easily fixed by tweaking some keyframes. but in most likely case the action itself may be broken due to the change in the model. for example if you were to change the origin point of the model and it fixed the issue for that action, all your other actions that rely on the origin point being in its original position may now be broken. either fix the issue in the external file, or redo the action in this one.

I finally got it. I think. Never can be too sure. Thanks for your responses.