Add and use typedefs, add doc

VirtualRobot/Nodes/HemisphereJoint/Joint.cpp

@@ -38,13 +38,13 @@ namespace VirtualRobot::hemisphere
     }
 
 
-    void Joint::computeFkOfPosition(const Eigen::Vector2d& p12)
+    void Joint::computeFkOfPosition(const ActuatorPosition& p12)
     {
         computeFkOfPosition(p12(0), p12(1));
     }
 
 
-    void Joint::computeFkOfAngle(const Eigen::Vector2d& alpha12)
+    void Joint::computeFkOfAngle(const ActuatorAngle& alpha12)
     {
         computeFkOfPosition(angleToPosition(alpha12));
     }
@@ -89,7 +89,8 @@ namespace VirtualRobot::hemisphere
         return jacobian;
     }
 
-    Eigen::Vector2d Joint::angleToPosition(const Eigen::Vector2d& alpha) const
+
+    Joint::ActuatorPosition Joint::angleToPosition(const Joint::ActuatorAngle& alpha) const
     {
         return lever * Eigen::sin((alpha + Eigen::Vector2d::Constant(theta0)).array());
     }

VirtualRobot/Nodes/HemisphereJoint/Joint.h

@@ -8,10 +8,19 @@
 namespace VirtualRobot::hemisphere
 {
 
+    /**
+     * @brief Hemisphere joint mathematics for FK and IK.
+     *
+     * This class is a wrapper about `Expressions`, which contains the actual
+     * math code that was generated from Python sympy expressions
+     * using `python/hemisphere-joint-demo/hemisphere_joint_demo/sympy_to_code.py`.
+     */
     class Joint
     {
     public:
 
+        using ActuatorPosition = Eigen::Vector2d;
+        using ActuatorAngle = Eigen::Vector2d;
         using Jacobian = Eigen::Matrix<double, 6, 2>;
 
     public:
@@ -23,18 +32,19 @@ namespace VirtualRobot::hemisphere
         void setConstants(double lever, double theta0);
 
 
-        void computeFkOfAngle(const Eigen::Vector2d& alpha12);
+        void computeFkOfAngle(const ActuatorAngle& alpha12);
 
-        void computeFkOfPosition(const Eigen::Vector2d& p12);
+        void computeFkOfPosition(const ActuatorPosition& p12);
         void computeFkOfPosition(double p1, double p2);
 
 
         Eigen::Vector3d getEndEffectorTranslation() const;
         Eigen::Matrix3d getEndEffectorRotation() const;
         Eigen::Matrix4d getEndEffectorTransform() const;
+
         Jacobian getJacobian() const;
 
-        Eigen::Vector2d angleToPosition(const Eigen::Vector2d& alpha) const;
+        ActuatorPosition angleToPosition(const ActuatorAngle& alpha) const;
 
 
     public: