Upstream status: Pending.
https://github.com/orocos/orocos_kinematics_dynamics/pull/44

Index: orocos_kinematics_dynamics-1.3.0/python_orocos_kdl/CMakeLists.txt
===================================================================
--- orocos_kinematics_dynamics-1.3.0.orig/python_orocos_kdl/CMakeLists.txt
+++ orocos_kinematics_dynamics-1.3.0/python_orocos_kdl/CMakeLists.txt
@@ -8,7 +8,7 @@ link_directories(${orocos_kdl_LIBRARY_DI
 
 find_package(PythonInterp REQUIRED)
 find_package(PythonLibs ${PYTHON_VERSION_MAJOR}.${PYTHON_VERSION_MINOR} REQUIRED)
-execute_process(COMMAND ${PYTHON_EXECUTABLE} -c "from distutils.sysconfig import get_python_lib; print get_python_lib(plat_specific=True, prefix='')" OUTPUT_VARIABLE PYTHON_SITE_PACKAGES OUTPUT_STRIP_TRAILING_WHITESPACE)
+execute_process(COMMAND ${PYTHON_EXECUTABLE} -c "from distutils.sysconfig import get_python_lib; print(get_python_lib(plat_specific=True, prefix=''))" OUTPUT_VARIABLE PYTHON_SITE_PACKAGES OUTPUT_STRIP_TRAILING_WHITESPACE)
 list(APPEND CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)
 find_package(SIP REQUIRED)
 include(SIPMacros)
Index: orocos_kinematics_dynamics-1.3.0/python_orocos_kdl/PyKDL/std_string.sip
===================================================================
--- orocos_kinematics_dynamics-1.3.0.orig/python_orocos_kdl/PyKDL/std_string.sip
+++ orocos_kinematics_dynamics-1.3.0/python_orocos_kdl/PyKDL/std_string.sip
@@ -27,7 +27,7 @@
     newstring = PyUnicode_DecodeUTF8(sipCpp->c_str(), sipCpp->length(), NULL);
     if(newstring == NULL) {
         PyErr_Clear();
-        newstring = PyString_FromString(sipCpp->c_str());
+        newstring = PyUnicode_FromString(sipCpp->c_str());
     }
     return newstring;
 %End
@@ -38,21 +38,27 @@
     // If argument is a Unicode string, just decode it to UTF-8
     // If argument is a Python string, assume it's UTF-8
      if (sipIsErr == NULL)
+#if PY_MAJOR_VERSION < 3
         return (PyString_Check(sipPy) || PyUnicode_Check(sipPy));
+#else
+        return PyUnicode_Check(sipPy);
+#endif
      if (sipPy == Py_None) {
         *sipCppPtr = new std::string;
          return 1;
      }
      if (PyUnicode_Check(sipPy)) {
         PyObject* s = PyUnicode_AsEncodedString(sipPy, "UTF-8", "");
-        *sipCppPtr = new std::string(PyString_AS_STRING(s));
+        *sipCppPtr = new std::string(PyUnicode_AS_DATA(s));
         Py_DECREF(s);
         return 1;
      }
+#if PY_MAJOR_VERSION < 3
      if (PyString_Check(sipPy)) {
         *sipCppPtr = new std::string(PyString_AS_STRING(sipPy));
         return 1;
      }
+#endif
 
      return 0;
 %End