Simplify selection of constraint equations to be used (less error-prone, better understandable)

Author: tobolar

Modelica/Mechanics/MultiBody/Joints/Constraints/Revolute.mo

@@ -70,36 +70,25 @@ equation
   r_rel_a = Frames.resolve2(frame_a.R, frame_b.r_0 - frame_a.r_0);
 
   // Constraint equations concerning translations
-  if x_locked and y_locked and z_locked then
-    r_rel_a=zeros(3);
-  elseif x_locked and y_locked and not z_locked then
+  if x_locked then
     r_rel_a[1]=0;
-    r_rel_a[2]=0;
-    frame_a.f[3]=0;
-  elseif x_locked and not y_locked and z_locked then
-    r_rel_a[1]=0;
-    r_rel_a[3]=0;
-    frame_a.f[2]=0;
-  elseif x_locked and not y_locked and not z_locked then
-    r_rel_a[1]=0;
-    frame_a.f[2]=0;
-    frame_a.f[3]=0;
-  elseif not x_locked and y_locked and z_locked then
-    r_rel_a[2]=0;
-    r_rel_a[3]=0;
+  else
     frame_a.f[1]=0;
-  elseif not x_locked and y_locked and not z_locked then
+  end if;
+
+  if y_locked then
     r_rel_a[2]=0;
-    frame_a.f[1]=0;
-    frame_a.f[3]=0;
-  elseif not x_locked and not y_locked and z_locked then
-    r_rel_a[3]=0;
-    frame_a.f[1]=0;
+  else
     frame_a.f[2]=0;
+  end if;
+
+  if z_locked then
+    r_rel_a[3]=0;
   else
-    frame_a.f=zeros(3);
+    frame_a.f[3]=0;
   end if;
 
+
   // Constraint equations concerning rotations
   0 = ex_a*R_rel.T*e;
   0 = ey_a*R_rel.T*e;

Modelica/Mechanics/MultiBody/Joints/Constraints/Spherical.mo

@@ -52,36 +52,25 @@ equation
   r_rel_a = MBS.Frames.resolve2(frame_a.R, frame_b.r_0 - frame_a.r_0);
 
   // Constraint equations concerning translation
-  if x_locked and y_locked and z_locked then
-    r_rel_a=zeros(3);
-  elseif x_locked and y_locked and not z_locked then
+  if x_locked then
     r_rel_a[1]=0;
-    r_rel_a[2]=0;
-    frame_a.f[3]=0;
-  elseif x_locked and not y_locked and z_locked then
-    r_rel_a[1]=0;
-    r_rel_a[3]=0;
-    frame_a.f[2]=0;
-  elseif x_locked and not y_locked and not z_locked then
-    r_rel_a[1]=0;
-    frame_a.f[2]=0;
-    frame_a.f[3]=0;
-  elseif not x_locked and y_locked and z_locked then
-    r_rel_a[2]=0;
-    r_rel_a[3]=0;
+  else
     frame_a.f[1]=0;
-  elseif not x_locked and y_locked and not z_locked then
+  end if;
+
+  if y_locked then
     r_rel_a[2]=0;
-    frame_a.f[1]=0;
-    frame_a.f[3]=0;
-  elseif not x_locked and not y_locked and z_locked then
-    r_rel_a[3]=0;
-    frame_a.f[1]=0;
+  else
     frame_a.f[2]=0;
+  end if;
+
+  if z_locked then
+    r_rel_a[3]=0;
   else
-    frame_a.f=zeros(3);
+    frame_a.f[3]=0;
   end if;
 
+
   //frame_a.t = zeros(3);
   frame_b.t = zeros(3);
   frame_b.f = -MBS.Frames.resolve2(R_rel, frame_a.f);

Modelica/Mechanics/MultiBody/Joints/Constraints/Universal.mo

@@ -46,35 +46,24 @@ equation
   r_rel_a = MBS.Frames.resolve2(frame_a.R, frame_b.r_0 - frame_a.r_0);
 
   // Constraint equations concerning translations
-  if x_locked and y_locked and z_locked then
-    r_rel_a=zeros(3);
-  elseif x_locked and y_locked and not z_locked then
+  if x_locked then
     r_rel_a[1]=0;
-    r_rel_a[2]=0;
-    frame_a.f[3]=0;
-  elseif x_locked and not y_locked and z_locked then
-    r_rel_a[1]=0;
-    r_rel_a[3]=0;
-    frame_a.f[2]=0;
-  elseif x_locked and not y_locked and not z_locked then
-    r_rel_a[1]=0;
-    frame_a.f[2]=0;
-    frame_a.f[3]=0;
-  elseif not x_locked and y_locked and z_locked then
-    r_rel_a[2]=0;
-    r_rel_a[3]=0;
+  else
     frame_a.f[1]=0;
-  elseif not x_locked and y_locked and not z_locked then
+  end if;
+
+  if y_locked then
     r_rel_a[2]=0;
-    frame_a.f[1]=0;
-    frame_a.f[3]=0;
-  elseif not x_locked and not y_locked and z_locked then
-    r_rel_a[3]=0;
-    frame_a.f[1]=0;
+  else
     frame_a.f[2]=0;
+  end if;
+
+  if z_locked then
+    r_rel_a[3]=0;
   else
-    frame_a.f=zeros(3);
+    frame_a.f[3]=0;
   end if;
+
   // Constraint equations concerning rotations
   frame_a.t*n_a=0;
   frame_b.t*n_b=0;