juelg · Oct 14, 2026 · Aug 26, 2026 · Aug 26, 2026 · Aug 26, 2026 · Oct 13, 2026
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -45,9 +45,8 @@ FetchContent_Declare(pybind11
     EXCLUDE_FROM_ALL
 )
 FetchContent_Declare(Eigen3
-    GIT_REPOSITORY https://gitlab.com/libeigen/eigen.git
-    GIT_TAG 3.4.1
-    GIT_PROGRESS TRUE
+    # release tarball instead of a git clone: gitlab.com often rejects clones of eigen due to load
+    URL https://gitlab.com/libeigen/eigen/-/archive/3.4.1/eigen-3.4.1.tar.gz
     EXCLUDE_FROM_ALL
 )
 FetchContent_Declare(

diff --git a/README.md b/README.md
@@ -82,6 +82,7 @@ if __name__ == "__main__":
     ik = rcs.common.Pin(
         kinematic_model_path,
         attachment_site,
+        joint_limits=robot_cfg.joint_limits,
     )
 
     # base env

diff --git a/docs/getting_started/index.md b/docs/getting_started/index.md
@@ -71,7 +71,7 @@ import numpy as np
 # Load simulation scene
 robot_meta = rcs.ROBOTS[rcs.common.RobotType.FR3]
 simulation = sim.Sim(rcs.SCENE_PATHS["empty_world"])
-ik = rcs.common.Pin(robot_meta.mjcf_model_path, robot_meta.attachment_site)
+ik = rcs.common.Pin(robot_meta.mjcf_model_path, robot_meta.attachment_site, joint_limits=robot_meta.joint_limits)
 
 # Configure robot
 cfg = sim.SimRobotConfig()

diff --git a/examples/fr3/fr3_direct_control.py b/examples/fr3/fr3_direct_control.py
@@ -79,6 +79,7 @@ def main():
             ik = rcs.common.Pin(
                 kinematic_model_path,
                 attachment_site,
+                joint_limits=robot_cfg.joint_limits,
             )
             robot = rcs.sim.SimRobot(simulation, ik, robot_cfg)
 
@@ -115,6 +116,7 @@ def main():
                 fr3_cfg.kinematic_model_path,
                 fr3_cfg.attachment_site,
                 urdf=fr3_cfg.kinematic_model_path.endswith(".urdf"),
+                joint_limits=fr3_cfg.joint_limits,
             )
             robot = hw.Franka(fr3_cfg, ik)
 

diff --git a/examples/fr3/fr3_env_cartesian_control.py b/examples/fr3/fr3_env_cartesian_control.py
@@ -59,6 +59,7 @@ def main():
         ik = rcs.common.Pin(
             kinematic_model_path,
             attachment_site,
+            joint_limits=robot_cfg.joint_limits,
         )
 
         robot = rcs.sim.SimRobot(simulation, ik, robot_cfg)

diff --git a/examples/fr3/fr3_env_joint_control.py b/examples/fr3/fr3_env_joint_control.py
@@ -59,6 +59,7 @@ def main():
         ik = rcs.common.Pin(
             kinematic_model_path,
             attachment_site,
+            joint_limits=robot_cfg.joint_limits,
         )
         mjmodel = scene.create_model(cfg)
         simulation = sim.Sim(mjmodel, sim_cfg)

diff --git a/examples/fr3/fr3_readme.py b/examples/fr3/fr3_readme.py
@@ -41,6 +41,7 @@
     ik = rcs.common.Pin(
         kinematic_model_path,
         attachment_site,
+        joint_limits=robot_cfg.joint_limits,
     )
 
     # base env

diff --git a/examples/so101/so101_env_cartesian_control.py b/examples/so101/so101_env_cartesian_control.py
@@ -40,6 +40,7 @@ def main():
     ik = rcs.common.Pin(
         kinematic_model_path,
         attachment_site,
+        joint_limits=robot_cfg.joint_limits,
     )
 
     robot = rcs.sim.SimRobot(simulation, ik, robot_cfg)

diff --git a/examples/so101/so101_env_joint_control.py b/examples/so101/so101_env_joint_control.py
@@ -38,6 +38,7 @@ def main():
     ik = rcs.common.Pin(
         kinematic_model_path,
         attachment_site,
+        joint_limits=robot_cfg.joint_limits,
     )
     mjmodel = scene.create_model(cfg)
     simulation = sim.Sim(mjmodel, sim_cfg)

diff --git a/examples/ur5e/ur5e_env_cartesian_control.py b/examples/ur5e/ur5e_env_cartesian_control.py
@@ -59,6 +59,7 @@ def main():
         ik = rcs.common.Pin(
             kinematic_model_path,
             attachment_site,
+            joint_limits=robot_cfg.joint_limits,
         )
 
         robot = rcs.sim.SimRobot(simulation, ik, robot_cfg)

diff --git a/examples/ur5e/ur5e_env_joint_control.py b/examples/ur5e/ur5e_env_joint_control.py
@@ -58,6 +58,7 @@ def main():
         ik = rcs.common.Pin(
             kinematic_model_path,
             attachment_site,
+            joint_limits=robot_cfg.joint_limits,
         )
         mjmodel = scene.create_model(sim_cfg_data)
         simulation = sim.Sim(mjmodel, sim_cfg)

diff --git a/examples/xarm7/xarm7_env_cartesian_control.py b/examples/xarm7/xarm7_env_cartesian_control.py
@@ -64,6 +64,7 @@ def main():
         ik = rcs.common.Pin(
             kinematic_model_path,
             attachment_site,
+            joint_limits=robot_cfg.joint_limits,
         )
 
         robot = rcs.sim.SimRobot(simulation, ik, robot_cfg)

diff --git a/examples/xarm7/xarm7_env_joint_control.py b/examples/xarm7/xarm7_env_joint_control.py
@@ -61,6 +61,7 @@ def main():
         ik = rcs.common.Pin(
             kinematic_model_path,
             attachment_site,
+            joint_limits=robot_cfg.joint_limits,
         )
         mjmodel = scene.create_model(sim_cfg_data)
         simulation = sim.Sim(mjmodel, sim_cfg)

diff --git a/examples/yam/yam_env_cartesian_control.py b/examples/yam/yam_env_cartesian_control.py
@@ -80,6 +80,7 @@ def main():
         ik = rcs.common.Pin(
             kinematic_model_path,
             attachment_site,
+            joint_limits=robot_cfg.joint_limits,
         )
 
         robot = rcs.sim.SimRobot(simulation, ik, robot_cfg)

diff --git a/extensions/rcs_fr3/CMakeLists.txt b/extensions/rcs_fr3/CMakeLists.txt
@@ -62,9 +62,8 @@ FetchContent_Declare(pybind11
     EXCLUDE_FROM_ALL
 )
 FetchContent_Declare(Eigen3
-    GIT_REPOSITORY https://gitlab.com/libeigen/eigen.git
-    GIT_TAG 3.4.1
-    GIT_PROGRESS TRUE
+    # release tarball instead of a git clone: gitlab.com often rejects clones of eigen due to load
+    URL https://gitlab.com/libeigen/eigen/-/archive/3.4.1/eigen-3.4.1.tar.gz
     EXCLUDE_FROM_ALL
     OVERRIDE_FIND_PACKAGE
 )

diff --git a/extensions/rcs_fr3/src/rcs_fr3/creators.py b/extensions/rcs_fr3/src/rcs_fr3/creators.py
@@ -188,6 +188,7 @@ def create_env(self, cfg: FR3HardwareEnvCreatorConfig) -> gym.Env:
             cfg.robot_cfg.kinematic_model_path,
             cfg.robot_cfg.attachment_site,
             urdf=cfg.robot_cfg.kinematic_model_path.endswith(".urdf"),
+            joint_limits=cfg.robot_cfg.joint_limits,
         )
         robot = hw.Franka(cfg.robot_cfg, ik)
 

diff --git a/extensions/rcs_panda/CMakeLists.txt b/extensions/rcs_panda/CMakeLists.txt
@@ -68,9 +68,8 @@ FetchContent_Declare(pybind11
     EXCLUDE_FROM_ALL
 )
 FetchContent_Declare(Eigen3
-    GIT_REPOSITORY https://gitlab.com/libeigen/eigen.git
-    GIT_TAG 3.4.1
-    GIT_PROGRESS TRUE
+    # release tarball instead of a git clone: gitlab.com often rejects clones of eigen due to load
+    URL https://gitlab.com/libeigen/eigen/-/archive/3.4.1/eigen-3.4.1.tar.gz
     EXCLUDE_FROM_ALL
     OVERRIDE_FIND_PACKAGE
 )

diff --git a/extensions/rcs_panda/src/rcs_panda/configs.py b/extensions/rcs_panda/src/rcs_panda/configs.py
@@ -24,6 +24,7 @@ def config(self) -> PandaHardwareEnvCreatorConfig:
         robot_cfg.kinematic_model_path = rcs.ROBOTS[RobotType.Panda].mjcf_model_path
         robot_cfg.tcp_offset = common.Pose(common.FrankaHandTCPOffset())
         robot_cfg.attachment_site = rcs.ROBOTS[RobotType.Panda].attachment_site
+        robot_cfg.joint_limits = rcs.ROBOTS[RobotType.Panda].joint_limits
         robot_cfg.speed_factor = 0.1
         robot_cfg.ik_solver = hw.IKSolver.rcs_ik
         robot_cfg.async_control = False

diff --git a/extensions/rcs_panda/src/rcs_panda/creators.py b/extensions/rcs_panda/src/rcs_panda/creators.py
@@ -148,6 +148,7 @@ def create_env(self, cfg: PandaHardwareEnvCreatorConfig) -> gym.Env:
             cfg.robot_cfg.kinematic_model_path,
             cfg.robot_cfg.attachment_site,
             urdf=cfg.robot_cfg.kinematic_model_path.endswith(".urdf"),
+            joint_limits=cfg.robot_cfg.joint_limits,
         )
         robot = hw.Franka(cfg.robot_cfg, ik)
 

diff --git a/extensions/rcs_so101/CMakeLists.txt b/extensions/rcs_so101/CMakeLists.txt
@@ -51,9 +51,8 @@ FetchContent_Declare(pybind11
     EXCLUDE_FROM_ALL
 )
 FetchContent_Declare(Eigen3
-    GIT_REPOSITORY https://gitlab.com/libeigen/eigen.git
-    GIT_TAG 3.4.1
-    GIT_PROGRESS TRUE
+    # release tarball instead of a git clone: gitlab.com often rejects clones of eigen due to load
+    URL https://gitlab.com/libeigen/eigen/-/archive/3.4.1/eigen-3.4.1.tar.gz
     EXCLUDE_FROM_ALL
 )
 FetchContent_MakeAvailable(pybind11 Eigen3)

diff --git a/extensions/rcs_ur5e/src/rcs_ur5e/creators.py b/extensions/rcs_ur5e/src/rcs_ur5e/creators.py
@@ -109,6 +109,7 @@ def create_env(self, cfg: UR5eHardwareEnvCreatorConfig) -> gym.Env:
             cfg.robot_cfg.kinematic_model_path,
             cfg.robot_cfg.attachment_site,
             urdf=cfg.robot_cfg.kinematic_model_path.endswith(".urdf"),
+            joint_limits=cfg.robot_cfg.joint_limits,
         )
         robot = UR5e(cfg.robot_cfg, ik)
         env: gym.Env = HardwareEnv(frequency=cfg.frequency)

diff --git a/extensions/rcs_ur5e/src/rcs_ur5e/scripts/test_robot.py b/extensions/rcs_ur5e/src/rcs_ur5e/scripts/test_robot.py
@@ -12,6 +12,7 @@
     robot_config.kinematic_model_path,
     robot_config.attachment_site,
     urdf=robot_config.kinematic_model_path.endswith(".urdf"),
+    joint_limits=robot_config.joint_limits,
 )
 robot = UR5e(robot_config, ik)
 print(f"Robot joint positions: {robot.get_joint_position()}")

diff --git a/extensions/rcs_xarm7/src/rcs_xarm7/creators.py b/extensions/rcs_xarm7/src/rcs_xarm7/creators.py
@@ -104,6 +104,7 @@ def create_env(self, cfg: XArm7HardwareEnvCreatorConfig) -> gym.Env:
             cfg.robot_cfg.kinematic_model_path,
             cfg.robot_cfg.attachment_site,
             urdf=cfg.robot_cfg.kinematic_model_path.endswith(".urdf"),
+            joint_limits=cfg.robot_cfg.joint_limits,
         )
         robot = XArm7(cfg=cfg.robot_cfg, ik=ik)
         env: gym.Env = HardwareEnv(frequency=cfg.frequency)

diff --git a/extensions/rcs_yam/README.md b/extensions/rcs_yam/README.md
@@ -91,7 +91,7 @@ from rcs import common
 from rcs_yam.hw import Yam, YamConfig, YamGripper
 
 cfg = YamConfig(channel="can0", async_control=False, dof=6, ...)
-ik = common.Pin(cfg.kinematic_model_path, cfg.attachment_site)
+ik = common.Pin(cfg.kinematic_model_path, cfg.attachment_site, joint_limits=cfg.joint_limits)
 robot = Yam(cfg, ik)
 gripper = YamGripper(common.GripperConfig(gripper_type=common.GripperType("Yam")), robot)
 

diff --git a/extensions/rcs_yam/src/rcs_yam/creators.py b/extensions/rcs_yam/src/rcs_yam/creators.py
@@ -103,6 +103,7 @@ def create_env(self, cfg: YamHardwareEnvCreatorConfig) -> gym.Env:
             cfg.robot_cfg.kinematic_model_path,
             cfg.robot_cfg.attachment_site,
             urdf=cfg.robot_cfg.kinematic_model_path.endswith(".urdf"),
+            joint_limits=cfg.robot_cfg.joint_limits,
         )
         robot = Yam(cfg.robot_cfg, ik)
         env: gym.Env = HardwareEnv(frequency=cfg.frequency)

diff --git a/extensions/rcs_yam/src/rcs_yam/scripts/test_robot.py b/extensions/rcs_yam/src/rcs_yam/scripts/test_robot.py
@@ -30,6 +30,7 @@
     robot_config.kinematic_model_path,
     robot_config.attachment_site,
     urdf=robot_config.kinematic_model_path.endswith(".urdf"),
+    joint_limits=robot_config.joint_limits,
 )
 robot = Yam(robot_config, ik)
 gripper = YamGripper(common.GripperConfig(gripper_type=gripper_type), robot)

diff --git a/include/rcs/Kinematics.h b/include/rcs/Kinematics.h
@@ -34,12 +34,27 @@ class Pin : public Kinematics {
   const double DT = 1e-1;
   const double damp = 1e-6;
   int FRAME_ID;
+  Pose base_pose;
 
   pinocchio::Model model;
   pinocchio::Data data;
 
+  VectorXd q_lower;
+  VectorXd q_upper;
+  bool enforce_limits;
+
+  VectorXd nullspace_q;
+  double nullspace_gain;
+
+  bool solve(const pinocchio::SE3& oMdes, VectorXd& q, double nullspace_gain);
+
  public:
-  Pin(const std::string& path, const std::string& frame_id, bool urdf);
+  Pin(const std::string& path, const std::string& frame_id, bool urdf,
+      const VectorXd& nullspace_q = VectorXd(), double nullspace_gain = 0.0,
+      bool enforce_limits = true,
+      const std::optional<std::string>& base_frame = std::nullopt,
+      const std::optional<Eigen::Matrix<double, 2, Eigen::Dynamic>>&
+          joint_limits = std::nullopt);
   std::optional<VectorXd> inverse(
       const Pose& pose, const VectorXd& q0,
       const Pose& tcp_offset = Pose::Identity()) override;

diff --git a/python/rcs/__init__.py b/python/rcs/__init__.py
@@ -110,8 +110,8 @@ class RobotMetaConfig:
         q_home=np.array([0.0, -np.pi / 4, 0.0, -3 * np.pi / 4, 0.0, np.pi / 2, 0.0]),
         joint_limits=np.array(
             [
-                [-2.3476, -1.5454, -2.4937, -2.7714, -2.5100, 0.7773, -2.7045],
-                [2.3476, 1.5454, 2.4937, -0.4226, 2.5100, 4.2841, 2.7045],
+                [-2.9007, -1.8361, -2.9007, -3.0770, -2.8763, 0.4398, -3.0508],
+                [2.9007, 1.8361, 2.9007, -0.1169, 2.8763, 4.6216, 3.0508],
             ]
         ),
     ),

diff --git a/python/rcs/_core/common.pyi b/python/rcs/_core/common.pyi
@@ -315,7 +315,37 @@ class RotVec:
     ) -> numpy.ndarray[tuple[typing.Literal[3], typing.Literal[3]], numpy.dtype[numpy.float64]]: ...
 
 class Pin(Kinematics):
-    def __init__(self, path: str, frame_id: str = "fr3_link8", urdf: bool = False) -> None: ...
+    def __init__(
+        self,
+        path: str,
+        frame_id: str = "fr3_link8",
+        urdf: bool = False,
+        nullspace_q: numpy.ndarray[tuple[M], numpy.dtype[numpy.float64]] = ...,
+        nullspace_gain: float = 0.0,
+        enforce_limits: bool = True,
+        base_frame: str | None = None,
+        joint_limits: numpy.ndarray[tuple[typing.Literal[2], M], numpy.dtype[numpy.float64]] | None = None,
+    ) -> None:
+        """
+        Numerical inverse kinematics (damped least squares) on a Pinocchio model.
+
+        Args:
+            path: MJCF or URDF file of the robot.
+            frame_id: Frame whose pose forward and inverse refer to, usually the attachment site.
+            urdf: Load ``path`` as URDF instead of MJCF.
+            nullspace_q: Preferred posture of the joints, used as a secondary task in the null space of
+                the pose task. Missing entries are filled with zeros.
+            nullspace_gain: Gain of the posture task, 0 disables it. Gains above 1/dt are capped to 1/dt.
+                If the posture task keeps the solver from reaching the pose, the solve is repeated without it.
+            enforce_limits: Clamp every solver step to the joint limits.
+            base_frame: Frame fixed to the world in which poses are expressed. None uses the root body of
+                the model, whose own pose Pinocchio ignores.
+            joint_limits: Joint limits for the clamping as a 2 x n matrix, lower limits in the first row and
+                upper limits in the second, usually the ``joint_limits`` of the robot config. They replace
+                the limits of the first n joints and must not cover more joints than the model has. None
+                uses the joint ranges of the MJCF or URDF. Joints with an infinite limit or an empty range
+                (lower >= upper) are treated as unlimited. Only used if ``enforce_limits`` is True.
+        """
 
 def FrankaHandTCPOffset() -> numpy.ndarray[tuple[typing.Literal[4], typing.Literal[4]], numpy.dtype[numpy.float64]]: ...
 def IdentityRotMatrix() -> numpy.ndarray[tuple[typing.Literal[3], typing.Literal[3]], numpy.dtype[numpy.float64]]: ...

diff --git a/python/rcs/envs/scenes.py b/python/rcs/envs/scenes.py
@@ -353,6 +353,7 @@ def create_env_from_model(self, cfg: SimEnvCreatorConfig, mjmodel: MjModel) -> g
             ik = rcs.common.Pin(
                 kinematic_model_path,
                 attachment_site,
+                joint_limits=prefixed_cfg.robot_cfgs[robot_name].joint_limits,
             )
 
             env = self.add_robot_env(prefixed_cfg, robot_name, env, simulation, ik)

diff --git a/python/rcs/lerobot_joint_converter.py b/python/rcs/lerobot_joint_converter.py
@@ -124,6 +124,7 @@ def __init__(
         self.ik = rcs.common.Pin(
             rcs.ROBOTS[robot_type].mjcf_model_path,
             rcs.ROBOTS[robot_type].attachment_site,
+            joint_limits=rcs.ROBOTS[robot_type].joint_limits,
         )
         self.camera_resizers = {
             camera.name: v2.Resize(camera.resolution)  # type: ignore[name-defined]  # noqa: F821