FridgeKinematics:

  - Added class to perform forward and inverse kinematics.
  - Added basic test to hand verify results.
  - Added claw fridge collision check by Mr. Schuh.
  - Revered code review changes that broke the math.
  - Added tests for collision from Mr. Schuh.
  - Constants are working, thanks Brian.
  - Added velocity calculation based on jacobian.

Change-Id: Iba752fbe6ebecca6dfd3102b23c8aebc3cc652a2
diff --git a/frc971/constants.h b/frc971/constants.h
index d66853b..fe47418 100644
--- a/frc971/constants.h
+++ b/frc971/constants.h
@@ -116,6 +116,29 @@
 
   double max_allowed_left_right_arm_difference;
   double max_allowed_left_right_elevator_difference;
+
+  struct ClawGeometry {
+    // Horizontal distance from the center of the grabber to the end.
+    double grabber_half_length;
+    // Vertical distance from the arm rotation center to the bottom of the
+    // grabber.  Distance measured with arm vertical (theta = 0).
+    double grabber_delta_y;
+    // Vertical separation of the claw and arm rotation centers with the
+    // elevator at 0.0 and the arm angle set to zero.
+    double grabber_arm_vert_separation;
+    // Horizontal separation of the claw and arm rotation centers with the
+    // elevator at 0.0 and the arm angle set to zero.
+    double grabber_arm_horz_separation;
+    // Distance between the center of the claw to the top of the claw.
+    // The line drawn at this distance parallel to the claw centerline is used
+    // to determine if claw interfears with the grabber.
+    double claw_top_thickness;
+    // The grabber is safe at any height if it is behind this location.
+    double grabber_always_safe_h_min;
+    // The grabber is safe at any x if it is above this location.
+    double grabber_always_safe_x_max;
+  };
+  ClawGeometry clawGeometry;
 };
 
 // Creates (once) a Values instance for ::aos::network::GetTeamNumber() and