Update readme.md

Author: walchko

readme.md

@@ -19,3 +19,58 @@ module for my needs:
 - [pytransform3d](https://github.com/rock-learning/pytransform3d)
 - [robopy](https://github.com/MultipedRobotics/robopy)
 - [tinyik](https://github.com/lanius/tinyik), uses `open3d` to visualize the mechanism
+
+## Example
+
+```python
+import numpy as np
+from mdh.kinematic_chain import KinematicChain
+
+# make it print better
+np.set_printoptions(suppress=True)
+
+# modified DH parameters: alpha a theta d
+# types: revolute=1, prismatic=2 (not implemented yet)
+dh = [
+    {'alpha': 0,  'a': 0, 'theta': 0, 'd': 0, 'type': 1},
+    {'alpha': pi/2, 'a': 52, 'theta': 0, 'd': 0, 'type': 1},
+    {'alpha': 0, 'a': 89, 'theta': 0, 'd': 0, 'type': 1},
+    {'alpha': 0, 'a': 90, 'theta': 0, 'd': 0, 'type': 1},
+    {'alpha': 0, 'a': 95, 'theta': 0, 'd': 0, 'type': 1}
+]
+
+kc = KinematicChain.from_parameters(dh)
+
+# forward kinematics
+angles = np.deg2rad([-45.00, 77.41, -98.15, -69.27, 0])
+t = kc.forward(angles)
+print(f">> {t}")
+
+# inverse kinematics
+pt = [110,0,-70]
+deg = kc.inverse(pt)
+rad = np.rad2deg(deg)
+print(f">> {rad}")
+```
+
+# MIT License
+
+**Copyright (c) 2019 Kevin J. Walchko**
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.