Excluding joint from articulation causes some issue

Omniverse Isaac Sim
8

Hello, I dont use fixed joint to connect 2 robots, get the world pose of car chassis and set the value to franka world pose on every physics step.

example code

robot_to_chassis_rt_mat = np.eye(4)
robot_to_chassis_rt_mat[:3, 3] = np.array([-0.4, 0.0, 0.155])

def on_physics_step(self, step: float):
    chassis_pos, chassis_quat = mobile_robot_chassis.get_world_pose()
    chassis_r_mat = quats_to_rot_matrices(chassis_quat)
    chassis_rt_mat = np.eye(4)
    chassis_rt_mat[:3, :3] = chassis_r_mat
    chassis_rt_mat[:3, 3] = chassis_pos
    robot_pose = np.dot(chassis_rt_mat, robot_to_chassis_rt_mat)
    robot_pos = robot_pose[:3, 3]
    robot_quat = rot_matrices_to_quats(robot_pose[:3, :3])
    robot.set_world_pose(robot_pos, robot_quat)

Hope that helps