Interaction Force Simulation In the exoskeleton-human model

[zheng xiaojuan]

I have some problems that has been bothering me for a long time and I ask you to help me. In the OpenSim software, I built a model which is the human body worn exoskeleton, show in figure1. However, the model can only be IK simulation that walked on the floor with crutches. When RRA running, the beginning of the model disappeared, the end of the simulation the model has been gone, RRA output is the all values of zero. And it can’t run CMC, when the simulation of t = 0s, the process of simulation had been stuck fixed.
Human worn exoskeleton model:
1.Band constraints through by spring connect human body and exoskeleton, each spring restrained the movement of the human body and exoskeleton. Spring one side fixed on body segment, the other fixed on exoskeleton corresponding segment. Such as thigh spring one side fixed on the femur, the other fixed on the exoskeleton’s thigh.
2. Feet had two contact points although the four points contact the floor in real life. left foot and left crutch on the one force plate produced total force, right foot and right crutch on the other force plate produce total force. we just have two force plate, although we need four points contact the floor.
I want to ask your advice:
1.How to build the interaction between the exoskeleton and the human body, and which one constraint types we need chose?
2.Exoskeleton of the hip and the human pelvis is the relationship that parent body is pelvis and its child body is exoskeleton’s hip, is it reasonable?
3.The simulation of the model with crutches must need four contact points in the external force file that can be simulate the RRA successfully? In my model simulation always fail in the RRA and CMC, I have no idea to deal with these problem.
I’m appreciate to you will help me. I’m eagerly awaiting for you reply.
Fig1 model with exoskeleton stand on the ground and the IK simulate that walked on the ground. (I'm so sorry that figure can copy in this mail. if you want to further know detail about the model please reply me. my mail is 1356944031@qq.com)
Juan Zheng
2017/03/29

[Thomas Uchida]

How to build the interaction between the exoskeleton and the human body, and which one constraint types we need chose?

There's a relevant discussion on this Forum thread: viewtopicPhpbb.php?f=91&t=7465