robot-sim
diff --git a/‎spatialmath/base/transforms3d.py
Copy file name to clipboardExpand all lines: spatialmath/base/transforms3d.py
+7-3Lines changed: 7 additions & 3 deletions b/‎spatialmath/base/transforms3d.py
Copy file name to clipboardExpand all lines: spatialmath/base/transforms3d.py
+7-3Lines changed: 7 additions & 3 deletions
diff --git a/‎spatialmath/base/vectors.py
Copy file name to clipboardExpand all lines: spatialmath/base/vectors.py
+1-1Lines changed: 1 addition & 1 deletion b/‎spatialmath/base/vectors.py
Copy file name to clipboardExpand all lines: spatialmath/base/vectors.py
+1-1Lines changed: 1 addition & 1 deletion
diff --git a/‎spatialmath/quaternion.py
Copy file name to clipboardExpand all lines: spatialmath/quaternion.py
+4-4Lines changed: 4 additions & 4 deletions b/‎spatialmath/quaternion.py
Copy file name to clipboardExpand all lines: spatialmath/quaternion.py
+4-4Lines changed: 4 additions & 4 deletions
@@ -1769,14 +1769,18 @@ def exp2jac(v, theta=None):
 
     :seealso: :func:`eul2jac`, :func:`rpy2jac`, :func:`rot2jac`
     """
-    R = trexp(v)
+
+
+    vn, theta = base.unitvec_norm(v)
     if theta is None:
-        v, theta = base.unitvec_norm(v)
+        return np.eye(3)
+
+    R = trexp(v)
 
     z = np.eye(3,3) - R
     A = []
     for i in range(3):
-        dRdvi = v[i] * base.skew(v) + base.skew(np.cross(v, z[:,i])) / theta
+        dRdvi = vn[i] * base.skew(vn) + base.skew(np.cross(vn, z[:,i])) / theta
         x = base.vex(dRdvi)
         A.append(x)
     return np.c_[A].T
 
@@ -104,7 +104,7 @@ def unitvec_norm(v):
     if n > 100 * _eps:  # if greater than eps
         return (v / n, n)
     else:
-        return None
+        return None, None
 
 def norm(v):
     """
 
@@ -1931,14 +1931,14 @@ def increment(self, w, normalize=False):
         """
 
         # is (v, theta) or None
-        vt = base.unitvec_norm(w)
+        v, theta = base.unitvec_norm(w)
 
-        if vt is None:
+        if v is None:
             # zero update
             return
 
-        ds = math.cos(vt[1] / 2)
-        dv = math.sin(vt[1] / 2) * vt[0]
+        ds = math.cos(theta / 2)
+        dv = math.sin(theta / 2) * v
 
         updated = base.qqmul(self.A, np.r_[ds, dv])
         if normalize: