[ODE] making the floor rigid

[dvir schirman]

On 6/28/06, Jason Perkins <starkos at gmail.com> wrote:
>
> On 6/28/06, dvir schirman <dvir.boost at gmail.com> wrote:
> > How can I make my floor rigid, so the robot doesn't penetrate it?
>
> How have you implemented the floor? How have you implemented the
> robot? Are you sure that your collision shapes are properly aligned
> with your visual meshes?
>
> Jason


  Hi, here is my implementation of the world, the robot and the floor.
The robot is made out of three boxes atached with an hinge.



 world = dWorldCreate();

 dWorldSetGravity (world, 0, 0, -9.8);

 dWorldSetERP (world, 0.8);

 dWorldSetContactSurfaceLayer (world, 0.0001);

 dWorldSetCFM(world, 0.00001);

 space = dSimpleSpaceCreate (0);

 sim_surface.mode = dContactApprox1;

 sim_surface.mu = ROBOT2_SIM_MU;

contact_joint_group = dJointGroupCreate (0);

hinge_joint_group = dJointGroupCreate (0);
friction_joint_group = dJointGroupCreate (0);


dMass mass;

state_num=0;

flag_box2=0;

flag_box3=0;

ground.contact_num =0;

ground.body = 0;

ground.geom = dCreatePlane (space, 0, 0, 1 , 0);

box1.body = dBodyCreate (world);

box2.body = dBodyCreate (world);

box3.body = dBodyCreate (world);

dBodySetPosition(box1.body, BODY1_LX/2, 0, BODY1_LZ/2+H);

dBodySetPosition(box2.body, BODY2_LX/2+BODY1_LX+GAP, 0, BODY2_LZ/2+H);

dBodySetPosition(box3.body, BODY3_LX/2+BODY1_LX+BODY3_LX+2*GAP, 0,
BODY3_LZ/2+H);

dMassSetBoxTotal (&mass, BODY1_MASS,BODY1_LX , BODY1_LY, BODY1_LZ);

dBodySetMass (box1.body, &mass);

dMassSetBoxTotal (&mass, BODY2_MASS,BODY2_LX , BODY2_LY, BODY2_LZ);

dBodySetMass (box2.body, &mass);

dMassSetBoxTotal (&mass, BODY3_MASS,BODY3_LX , BODY3_LY, BODY3_LZ);

dBodySetMass (box3.body, &mass);

box1.geom = dCreateBox(space,BODY1_LX , BODY1_LY, BODY1_LZ);

box2.geom = dCreateBox(space,BODY2_LX , BODY2_LY, BODY2_LZ);

box3.geom = dCreateBox(space,BODY3_LX , BODY3_LY, BODY3_LZ);

dGeomSetBody (box1.geom, box1.body);

dGeomSetBody (box2.geom, box2.body);

dGeomSetBody (box3.geom, box3.body);

box1.contact_num = 0;

box2.contact_num = 0;

box3.contact_num = 0;

hinge1= dJointCreateHinge (world, hinge_joint_group);

hinge2= dJointCreateHinge (world, hinge_joint_group);

dJointAttach (hinge1, box1.body, box2.body);

dJointAttach (hinge2, box2.body, box3.body);

dJointSetHingeAnchor (hinge1, BODY1_LX + GAP/2, 0, BODY1_LZ/2);

dJointSetHingeAxis (hinge1, 0, 1, 0);

dJointSetHingeAnchor (hinge2, BODY1_LX + BODY2_LX + 3*GAP/2, 0, BODY2_LZ/2);


dJointSetHingeAxis (hinge2, 0, 1, 0);

sim_surface.mode = dContactApprox1;// | dContactSoftERP | dContactSoftCFM;

sim_surface.mu = ROBOT2_SIM_MU;



for(int i=0;i<MY_ODE_MAX_CONTACT_NUM;i++)

{

box1.contacts[i].surface = sim_surface;

box2.contacts[i].surface = sim_surface;

box3.contacts[i].surface = sim_surface;

}

--------------------------------------------------------

Here is the part of the header with my declarations:



dJointGroupID contact_joint_group; // group for contact joints



dJointGroupID hinge_joint_group; // group for robot hinge joints



dJointGroupID friction_joint_group; // group for robot friction joints



dWorldID world;

dSpaceID space;

dSurfaceParameters sim_surface; //default surfaces for simulation

-----------------------------------------------------------------------------



Thanks for your help.

Dvir
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