Implementation:Isaac sim IsaacGymEnvs Factory Control Algorithms

Knowledge Sources	Factory IsaacGymEnvs
Domains	Robotics, Control
Last Updated	2026-02-15 00:00 GMT

Overview

Stateless control functions that convert task-space targets from the RL policy into joint-space position targets or joint torques for the Franka robot.

Description

The factory_control module provides three core functions. compute_dof_pos_target() handles position-based controllers (joint_space_ik) by computing joint position targets via IK. compute_dof_torque() handles torque-based controllers (joint_space_id, task_space_impedance, operational_space_motion, open_loop_force, closed_loop_force, hybrid_force_motion) by computing joint torques. get_pose_error() is a shared utility that computes position and orientation errors between the current fingertip pose and the target pose.

All functions are stateless and operate on batched tensors, processing all environments in parallel on the GPU.

Usage

Use these functions in the pre_physics_step() method of any Factory or IndustReal task to convert RL policy outputs into robot commands. The controller type is selected via cfg_task.ctrl.controller_type.

Code Reference

Source Location

Repository: IsaacGymEnvs
File: isaacgymenvs/tasks/factory/factory_control.py, Lines 41-330

Signature

Position Target Computation

def compute_dof_pos_target(
    cfg_ctrl,
    arm_dof_pos,
    fingertip_midpoint_pos,
    fingertip_midpoint_quat,
    jacobian,
    ctrl_target_fingertip_midpoint_pos,
    ctrl_target_fingertip_midpoint_quat,
    ctrl_target_gripper_dof_pos,
    device
):
    """Compute joint position targets using IK.

    Supports controller_type: joint_space_ik
    IK methods: 'dls' (damped least squares), 'trans' (pseudoinverse)

    Returns:
        dof_pos_target: Joint position targets [num_envs, num_dofs]
    """

Torque Computation

def compute_dof_torque(
    cfg_ctrl,
    dof_pos,
    dof_vel,
    fingertip_midpoint_pos,
    fingertip_midpoint_quat,
    fingertip_midpoint_linvel,
    fingertip_midpoint_angvel,
    left_finger_force,
    right_finger_force,
    jacobian,
    arm_mass_matrix,
    ctrl_target_gripper_dof_pos,
    ctrl_target_fingertip_midpoint_pos,
    ctrl_target_fingertip_midpoint_quat,
    ctrl_target_fingertip_contact_wrench,
    device
):
    """Compute joint torques for torque-based controllers.

    Supports controller_type: joint_space_id, task_space_impedance,
        operational_space_motion, open_loop_force, closed_loop_force,
        hybrid_force_motion

    Returns:
        dof_torque: Joint torques [num_envs, num_dofs]
    """

Pose Error Utility

def get_pose_error(
    fingertip_midpoint_pos,
    fingertip_midpoint_quat,
    ctrl_target_fingertip_midpoint_pos,
    ctrl_target_fingertip_midpoint_quat,
    jacobian_type,
    rot_error_type
):
    """Compute position and orientation error between current and target poses.

    Args:
        jacobian_type: 'geometric' or 'analytic'
        rot_error_type: 'axis_angle' or 'quat'

    Returns:
        pos_error: Position error [num_envs, 3]
        rot_error: Orientation error [num_envs, 3]
    """

Import

from isaacgymenvs.tasks.factory import factory_control

I/O Contract

Inputs

Name	Type	Required	Description
cfg_ctrl	DictConfig	Yes	Controller configuration (controller_type, gains, jacobian_type)
arm_dof_pos	torch.Tensor	Yes	Current arm joint positions `[num_envs, 7]`
dof_pos	torch.Tensor	Yes (torque)	Full DOF positions `[num_envs, num_dofs]`
dof_vel	torch.Tensor	Yes (torque)	Full DOF velocities `[num_envs, num_dofs]`
fingertip_midpoint_pos	torch.Tensor	Yes	Current fingertip position `[num_envs, 3]`
fingertip_midpoint_quat	torch.Tensor	Yes	Current fingertip quaternion `[num_envs, 4]`
jacobian	torch.Tensor	Yes	Franka Jacobian `[num_envs, 6, num_dofs]`
arm_mass_matrix	torch.Tensor	Yes (torque)	Arm mass matrix `[num_envs, 7, 7]`
ctrl_target_fingertip_midpoint_pos	torch.Tensor	Yes	Target fingertip position from RL `[num_envs, 3]`
ctrl_target_fingertip_midpoint_quat	torch.Tensor	Yes	Target fingertip quaternion from RL `[num_envs, 4]`
ctrl_target_gripper_dof_pos	torch.Tensor	Yes	Target gripper joint positions `[num_envs, 2]`
ctrl_target_fingertip_contact_wrench	torch.Tensor	Conditional	Desired contact wrench for force controllers `[num_envs, 6]`
device	str	Yes	Torch device string

Outputs

Name	Type	Description
dof_pos_target	torch.Tensor	Joint position targets for position controllers `[num_envs, num_dofs]`
dof_torque	torch.Tensor	Joint torques for torque controllers `[num_envs, num_dofs]`
pos_error	torch.Tensor	Position error `[num_envs, 3]`
rot_error	torch.Tensor	Orientation error `[num_envs, 3]`

Controller Type Reference

Controller Type	Function	Output	IK Method	Use Case
`joint_space_ik`	`compute_dof_pos_target`	Joint positions	dls / trans	Default for position-controlled tasks
`joint_space_id`	`compute_dof_torque`	Joint torques	N/A	Torque-controlled robots
`task_space_impedance`	`compute_dof_torque`	Joint torques	N/A	Compliant contact tasks
`operational_space_motion`	`compute_dof_torque`	Joint torques	N/A	Redundant manipulator control
`open_loop_force`	`compute_dof_torque`	Joint torques	N/A	Force-controlled insertion
`closed_loop_force`	`compute_dof_torque`	Joint torques	N/A	Precise force regulation
`hybrid_force_motion`	`compute_dof_torque`	Joint torques	N/A	Assembly with directional force/motion split

Usage Examples

Position Control with IK

from isaacgymenvs.tasks.factory import factory_control

# In pre_physics_step():
dof_pos_target = factory_control.compute_dof_pos_target(
    cfg_ctrl=self.cfg_task.ctrl,
    arm_dof_pos=self.arm_dof_pos,
    fingertip_midpoint_pos=self.fingertip_midpoint_pos,
    fingertip_midpoint_quat=self.fingertip_midpoint_quat,
    jacobian=self.fingertip_midpoint_jacobian,
    ctrl_target_fingertip_midpoint_pos=self.ctrl_target_fingertip_midpoint_pos,
    ctrl_target_fingertip_midpoint_quat=self.ctrl_target_fingertip_midpoint_quat,
    ctrl_target_gripper_dof_pos=self.ctrl_target_gripper_dof_pos,
    device=self.device,
)
self.gym.set_dof_position_target_tensor(self.sim, gymtorch.unwrap_tensor(dof_pos_target))

Torque Control with Impedance

# With cfg_task.ctrl.controller_type = "task_space_impedance"
dof_torque = factory_control.compute_dof_torque(
    cfg_ctrl=self.cfg_task.ctrl,
    dof_pos=self.dof_pos,
    dof_vel=self.dof_vel,
    fingertip_midpoint_pos=self.fingertip_midpoint_pos,
    fingertip_midpoint_quat=self.fingertip_midpoint_quat,
    fingertip_midpoint_linvel=self.fingertip_midpoint_linvel,
    fingertip_midpoint_angvel=self.fingertip_midpoint_angvel,
    left_finger_force=self.left_finger_force,
    right_finger_force=self.right_finger_force,
    jacobian=self.fingertip_midpoint_jacobian,
    arm_mass_matrix=self.arm_mass_matrix,
    ctrl_target_gripper_dof_pos=self.ctrl_target_gripper_dof_pos,
    ctrl_target_fingertip_midpoint_pos=self.ctrl_target_fingertip_midpoint_pos,
    ctrl_target_fingertip_midpoint_quat=self.ctrl_target_fingertip_midpoint_quat,
    ctrl_target_fingertip_contact_wrench=self.ctrl_target_fingertip_contact_wrench,
    device=self.device,
)
self.gym.set_dof_actuation_force_tensor(self.sim, gymtorch.unwrap_tensor(dof_torque))

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