Some time ago, I had want to add legs to my test model (InMoov) in the IntegratedMovement (IM) service, but find out that something was lacking to work properly. By example, using the jMonkey simulator, when I make the right knee bent, it work fine and raise the foot. but if I also bent the left knee, it would raise the left foot and the robot will appear to be flying, wich is not even close of that will happen with the physical robot. So I need to find a way to make IM model act more in jMonkey to what a real robot will act. 

IM service was also in need of a major overhaul in how it work (relation with Servo, missplaced data etc)

Previously, we use a virtual robot in jMonkey with file(s) that contain j3o model linked with nodes. Servos will rotate the nodes and make the parts moves. But that structure will not work if I want to have the leg sometime moves in the normal way (upper leg to the origin of the robot, moves the foot) and sometimes in a reverse way (origin to the foot, and moves the rest of the body). But that could be more easily done and compute with the DH parameter and the Inverse Kinematic computation (IK). 

So I decide to change the data structure to be base on the DH parameters 

Each part of the robot (ie foot, ankle, bicep, neck etc) are define with DH parameters, it's 3d model and the control (Servo) that will move that part

IMPart partRightHipY = ik.createPart("harlRightHipY", 0.01);
partRightHipY.setDHParameters(ArmConfig.DEFAULT, 0.0415, 0, 0, -90);
partRightHipY.setDHParameters(ArmConfig.REVERSE, 0, 0, 0., 90); 
partRightHipY.setControl(ArmConfig.DEFAULT, "rightHipY");
partRightHipY.set3DModel("Models/harlRHipY.j3o", scale, new Point(0,0,0,0,0,0));
ik.attach(partRightHipY);

• Origin
  • Torso
    • leftArm
    • RightArm
      • thumb
      • index
      • major
    • head
  • LeftLeg
  • RightLeg

• Origin
  • RightLeg
    • Torso
      • leftArm
      • RightArm
    • LeftLeg

• Origin
  • rightArm
    • Torso
      • rightLeg
      • leftLeg
    • leftArm

and have it easy to know the end point of each arm

So far it's working good when moving 1 arm at time. (moves leftArm, using by example rightleg + torso + leftArm). But the IK engine can't currently resolve when ask to move leftarm to (x, y, z) and leftleg to (x1, y1, z1).

The reason is that the IK engine do one group of part at time and when moving two arms. So the commun part are moving one way, then another way for the other arm and never able to reach both target. With only the Torso as common part that do not moves a lot, the IK can manage to reach both target, but with a more complex and longer arm like the leg, it do not work. So I will need to have the IK engine be able to compute all the moves target at the same time