I input a joint1 to "forward_kinematics" function ,and return a position, then I input the position to "inverse_kinematics_frame", then return another joint2,but joint1 is not euqal to joint2. I use moveit in ros and verified, the result of ikpy "forward_kinematics" is true,but the result of ikpy "inverse_kinematics_frame" is error.

This PR adds a blender importer (that was first intended to be used with Aversive++). The PR makes #22 outdated and useless (so that I should close it if this one is accepted).

I tested your library, pretty decent by selecting active joints. However your library minimize its IK solver error by position not by its Orientation. In other words it solves for the Position of the Homo. Transformation Matrix and after that it checks orientation.

How I can solve for orientation as priority?

As I see in the code:

    def optimize_target(x):
        # y = np.append(starting_nodes_angles[:chain.first_active_joint], x)
        y = chain.active_to_full(x, starting_nodes_angles)
        squared_distance = np.linalg.norm(chain.forward_kinematics(y)[:3, -1] - target)
        return squared_distance

This section is specified for target which is position. Any suggestion for Orientation?

Hi, I'm trying to use ikpy with FreeCAD and can't find how to create a chain from object placements.

Placements are global coordinates and decomposable in Base (translation from origin) and Rotation (quaternion). I think I get a link origin_translation by subtraction of its Base by the last link Base but can't figure how to get the origin_rotation.

Thanks !

I really like to use a prismatic joint solution in my project. Could you please tell me a date for primsatic joint support? Or could you please tell me how it can be done?

If you can explain it I would like to do it by myself. Looking for your reply

Is it possible to change the optimization algorithm with a function call, or is it only possible to statically change line 134 in inverse_kinematics.py? With L-BFGS-B and joint boundaries I noticed a jumpy behavior in the end effector positions of the kinematic model, so I changed it to SLSQP.

The models, where this problems come up, can be found here: quadruped model

Following the getting started i got an issue with Setting the position of your chain (aka Inverse Kinematics, aka IK).

File "C:\Users\Jonas\untitled1.py", line 46, in frame_target[:3,:3] = target_position

ValueError: cannot copy sequence with size 4 to array axis with dimension 3

After changing the line to "frame_target = target_position" the error is gone and the presented results appear in the console. Am i just a noob or is this broken?

Hi, I am trying to create a chain from URDF file of Baxter and is facing following error. I can't figure out why? What is wrong in this declaration? Any help please

my_chain = ikpy.chain.Chain.from_urdf_file("../baxter_common/baxter_description/urdf/baxter.urdf",
    base_elements=["right_upper_shoulder", "right_lower_shoulder", "right_upper_elbow", "right_lower_elbow", 
                   "right_upper_forearm", "right_lower_forearm", "right_wrist", "right_hand"], 
    last_link_vector=[0.0, 0.0, 0.025], 
    active_links_mask=[False, True, True, True, True, True, True,True])

I am using this file: Baxter URDF

And get this error!!!

raise ValueError("Your active links mask length of {} is different from the number of your links, which is {}".format(len(active_links_mask), len(self.links)))
ValueError: Your active links mask length of 8 is different from the number of your links, which is 2

Hi, my name is koki. I got an error like that. I use anaconda3-5.3.1 and Python 3.5.6. I want to know why was it error happened?

`

import ikpy my_chain = ikpy.chain.Chain.from_urdf_file("model.urdf") Traceback (most recent call last): File "", line 1, in AttributeError: module 'ikpy' has no attribute 'chain' `

Python 3.7 has change the behavior of generators : when they reach the end now they emit a RuntimeError exception... In the file URDF_utils.py there are two occurences of next(...) that can raise RuntimeError exception, lines 91 and 103.

Line 103 "chain = list(next(it) for it in itertools.cycle(iters))" can be replaced by:

chain = []
    for it in itertools.cycle(iters):
        try:
            item = next(it)
        except:
            break
        chain.append(item)

Hello! I was trying to run the Quickstart tutorial for poppy-humanoid, and it's throwing an import error looking for the forward_kinematics file, which (after some digging) i found was deleted in this commit 164a5ba680191172f0177e9c59edc5939ce1d114

Should it still be around, or should that import be removed? It looked like it wasn't just a stray import because fk functions are used throughout the code, should the forward kinematics file be re-added or should all the references be removed?

thanks!

First off, this project is fantastic, it seriously helps with DIY arm development! I'm mostly asking if this is something within the purview of this library, but how do y'all feel about supporting interpolated values between two points, your current, and target position? I'm working on a pick and place (of a sort) robot, and a large part of the job is picking up items from one or several places, and placing it into a narrow, deep container. I know fora fact when I first got my homemade ik model off the ground, the arm would like, "swing" into position, and the only way around it was instead of one movement, many shorter segments of movements that shortened the amount the arm could "swing" (I'm sure theres a technical term I'm butchering, sorry).

I'm imagining an option in inverse_kinematics() that takes some sort of a parameter for tokenizing the movement into a list of movements. Maybe the value is a numSegments integer, or the default length unit, like millimeters per segment. Taking the concept to the nth degree so it doesnt feel like for loop syntactic sugar, I'm envisioning that target could be a list of values, so the model could be animated at a higher level, maybe even supporting velocity ~~suggestions~~ calculations given a max velocity value, maybe even per axis?

If thats outside of this libraries mission, I totally get it, just wanted to know if you guys were open to those sort of features as pull requests.

now i have a human 3d keypoints file. how can i get the pose euler rotation angle or quaternion with parent-child relationship like smpl pose, i want to use it to drive skeleton in blender or UE4. i have tested to make bvh file to use it in blender, but i want to run it in real time, so ineed to change the method. can you give me some adviences?

The current output is homogeneous coordinates. For generalized use of this software, it would make sense to have an option for the outputs to be in the context of 3D engines like Blender and Unity. Cartesian coordinates.

Hi, I try to conduct to draw a straight line by calculating inverse kinematics with niryo one robot.

input position (x : 0.073, y : 0.001, z : 0.168) input orientation (roll : 0.029, yaw: 1.407, pitch: 0.204) Answer of joints 1 ~ 6 axis : [ -0.007, 0.129, -1.360, 0.189, -0.183, -0.360]

I use blow's model.urdf code. Then, calculate inverse kinematics using these code lines.

Do you know any solution to solve this problem?

from ikpy.chain import Chain
my_chain = Chain.from_urdf_file("model.urdf")
print(my_chain)
ik = my_chain.inverse_kinematics(target_position=[0.083, 0.001, 0.168], target_orientation=[0.029, 1.407, 0.203],orientation_mode="all")
print(ik)
print(my_chain.forward_kinematics(ik)[:3, 3])
print(my_chain.forward_kinematics(ik))

I think the calculation of inverse kinematics is bad. The first line is correct, although the second line is wrong.

print(my_chain.forward_kinematics([0, 0.030, 0.152, -1.334, -0.184, -0.029, -0.030, 0])[:3, 3])
print(my_chain.inverse_kinematics(target_position=my_chain.forward_kinematics([0, 0.030, 0.152, -1.334, -0.184, -0.029, -0.030, 0])[:3, 3]))

<?xml version="1.0" ?>
<!-- =================================================================================== -->
<!-- |    This document was autogenerated by xacro from niryo_one.urdf.xacro           | -->
<!-- |    EDITING THIS FILE BY HAND IS NOT RECOMMENDED                                 | -->
<!-- =================================================================================== -->
<!--
    niryo_one.urdf.xacro
    Copyright (C) 2017 Niryo
    All rights reserved.

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
-->
<robot name="niryo_one" xmlns:xacro="http://www.ros.org/wiki/xacro">
  <!-- Properties -->
  <!-- Links -->
  <link name="world"/>
  <link name="base_link">
    <visual>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://niryo_one_description/meshes/v2/collada/base_link.dae"/>
      </geometry>
    </visual>
    <collision>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://niryo_one_description/meshes/v2/stl/base_link.stl"/>
      </geometry>
    </collision>
  </link>
  <link name="shoulder_link">
    <visual>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://niryo_one_description/meshes/v2/collada/shoulder_link.dae"/>
      </geometry>
    </visual>
    <collision>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://niryo_one_description/meshes/v2/stl/shoulder_link.stl"/>
      </geometry>
    </collision>
  </link>
  <link name="arm_link">
    <visual>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://niryo_one_description/meshes/v2/collada/arm_link.dae"/>
      </geometry>
    </visual>
    <collision>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://niryo_one_description/meshes/v2/stl/arm_link.stl"/>
      </geometry>
    </collision>
  </link>
  <link name="elbow_link">
    <visual>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://niryo_one_description/meshes/v2/collada/elbow_link.dae"/>
      </geometry>
    </visual>
    <collision>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://niryo_one_description/meshes/v2/stl/elbow_link.stl"/>
      </geometry>
    </collision>
  </link>
  <link name="forearm_link">
    <visual>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://niryo_one_description/meshes/v2/collada/forearm_link.dae"/>
      </geometry>
    </visual>
    <collision>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://niryo_one_description/meshes/v2/stl/forearm_link.stl"/>
      </geometry>
    </collision>
  </link>
  <link name="wrist_link">
    <visual>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://niryo_one_description/meshes/v2/collada/wrist_link.dae"/>
      </geometry>
    </visual>
    <collision>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://niryo_one_description/meshes/v2/stl/wrist_link.stl"/>
      </geometry>
    </collision>
  </link>
  <link name="hand_link">
    <visual>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://niryo_one_description/meshes/v2/collada/hand_link.dae"/>
      </geometry>
    </visual>
    <collision>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://niryo_one_description/meshes/v2/stl/hand_link.stl"/>
      </geometry>
    </collision>
  </link>
  <link name="tool_link">
	</link>
  <!--Joints -->
  <joint name="joint_world" type="fixed">
    <parent link="world"/>
    <child link="base_link"/>
    <origin rpy="0 0 0" xyz="0 0 0"/>
  </joint>
  <joint name="joint_1" type="revolute">
    <parent link="base_link"/>
    <child link="shoulder_link"/>
    <origin rpy="0 0 0" xyz="0 0 0.103"/>
    <axis xyz="0 0 1"/>
    <limit effort="1" lower="-3.05433" upper="3.05433" velocity="1.0"/>
  </joint>
  <joint name="joint_2" type="revolute">
    <parent link="shoulder_link"/>
    <child link="arm_link"/>
    <origin rpy="1.5707963268 -1.5707963268 0" xyz="0 0 0.08"/>
    <limit effort="1" lower="-1.5708" upper="0.640187" velocity="1.0"/>
    <axis xyz="0 0 1"/>
  </joint>
  <joint name="joint_3" type="revolute">
    <parent link="arm_link"/>
    <child link="elbow_link"/>
    <origin rpy="0 0 -1.5707963268" xyz="0.21 0.0 0"/>
    <limit effort="1" lower="-1.397485" upper="1.5707963268" velocity="1.0"/>
    <axis xyz="0 0 1"/>
  </joint>
  <joint name="joint_4" type="revolute">
    <parent link="elbow_link"/>
    <child link="forearm_link"/>
    <origin rpy="0 1.5707963268 0" xyz="0.0415 0.03 0"/>
    <limit effort="1" lower="-3.05433" upper="3.05433" velocity="1.0"/>
    <axis xyz="0 0 1"/>
  </joint>
  <joint name="joint_5" type="revolute">
    <parent link="forearm_link"/>
    <child link="wrist_link"/>
    <origin rpy="0 -1.5707963268 0" xyz="0 0 0.18"/>
    <limit effort="1" lower="-1.74533" upper="1.91986" velocity="1.0"/>
    <axis xyz="0 0 1"/>
  </joint>
  <joint name="joint_6" type="revolute">
    <parent link="wrist_link"/>
    <child link="hand_link"/>
    <origin rpy="0 1.5707963268 0" xyz="0.0164 -0.0055 0"/>
    <limit effort="1" lower="-2.57436" upper="2.57436" velocity="1.0"/>
    <axis xyz="0 0 1"/>
  </joint>
  <joint name="hand_tool_joint" type="fixed">
    <parent link="hand_link"/>
    <child link="tool_link"/>
    <origin rpy="-1.5707963268 -1.5707963268 0" xyz="0 0 0.0073"/>
  </joint>
</robot>

Hi,

I'm interested in running say 1000 independent IK queries on a gpu. In the readme you mention that this is a pure python library which means it theory it should work with numba relatively easily. Are there any caveats or thing I should be aware of if I'm going to try this?

Something similar to this: https://ipython-books.github.io/58-writing-massively-parallel-code-for-nvidia-graphics-cards-gpus-with-cuda/

Thanks