use only the animation of the lower body of a state machine and make it not affect the upper body

Development Character & Animation
1

Hello, I am a novice for UE4.
I’ve created a state machine that includes the movement animation of some first person characters,now I want to create a state machine for upper body animation,but try use Layered Blend per Bone,my character’s upper body has been rocking from side to side.How can I solve it.

2

Even iam facing the same problem can anyone help me?