Update vacuum logic for mechanical change

Change-Id: I78ea0c48df5a472ee2c38a5e072c2b0e540cb315
diff --git a/y2019/control_loops/superstructure/superstructure_lib_test.cc b/y2019/control_loops/superstructure/superstructure_lib_test.cc
index 4efb95f..0cce4a6 100644
--- a/y2019/control_loops/superstructure/superstructure_lib_test.cc
+++ b/y2019/control_loops/superstructure/superstructure_lib_test.cc
@@ -350,9 +350,9 @@
         CheckCollisions();
       }
 
-      const double loop_time =
-          chrono::duration_cast<chrono::duration<double>>(
-              monotonic_clock::now() - loop_start_time).count();
+      const double loop_time = chrono::duration_cast<chrono::duration<double>>(
+                                   monotonic_clock::now() - loop_start_time)
+                                   .count();
 
       const double elevator_acceleration =
           (superstructure_plant_.elevator_velocity() -
@@ -718,9 +718,8 @@
     ASSERT_TRUE(goal.Send());
   }
 
-  RunForTime(
-      Vacuum::kTimeAtHigherVoltage - chrono::milliseconds(10),
-      true, false);
+  RunForTime(Vacuum::kTimeAtHigherVoltage - chrono::milliseconds(10), true,
+             false);
 
   // Verify that at 0 pressure after short time voltage is still 12
   superstructure_plant_.set_simulated_pressure(0.0);
@@ -743,9 +742,8 @@
 
   // Verify that at 0 pressure after short time voltage is still high
   superstructure_plant_.set_simulated_pressure(0.0);
-  RunForTime(
-      Vacuum::kTimeAtHigherVoltage - chrono::milliseconds(10),
-      true, false);
+  RunForTime(Vacuum::kTimeAtHigherVoltage - chrono::milliseconds(10), true,
+             false);
   superstructure_queue_.output.FetchLatest();
   EXPECT_EQ(superstructure_queue_.output->pump_voltage, Vacuum::kPumpVoltage);
 
@@ -757,8 +755,8 @@
             Vacuum::kPumpHasPieceVoltage);
 }
 
-// Tests the Vacuum stays on for a bit after getting a no suck goal
-TEST_F(SuperstructureTest, VacuumStaysOn) {
+// Tests the Vacuum stops immediately after getting a no suck goal
+TEST_F(SuperstructureTest, VacuumStopsQuickly) {
   WaitUntilZeroed();
   // Turn on suction
   {
@@ -784,16 +782,8 @@
   }
 
   superstructure_plant_.set_simulated_pressure(1.0);
-  // Run for a short while and make sure we still ask for non-zero volts
-  RunForTime(Vacuum::kTimeToKeepPumpRunning -
-                 chrono::milliseconds(10),
-             true, false);
-  superstructure_queue_.output.FetchLatest();
-  EXPECT_GE(superstructure_queue_.output->pump_voltage,
-            Vacuum::kPumpHasPieceVoltage);
-
-  // Wait and make sure the vacuum actually turns off
-  RunForTime(chrono::seconds(2));
+  // Run for a short while and check that voltage dropped to 0
+  RunForTime(chrono::milliseconds(10), true, false);
   superstructure_queue_.output.FetchLatest();
   EXPECT_EQ(superstructure_queue_.output->pump_voltage, 0.0);
 }
diff --git a/y2019/control_loops/superstructure/vacuum.cc b/y2019/control_loops/superstructure/vacuum.cc
index d4c1c6b..7bf2e94 100644
--- a/y2019/control_loops/superstructure/vacuum.cc
+++ b/y2019/control_loops/superstructure/vacuum.cc
@@ -7,14 +7,13 @@
 constexpr double Vacuum::kPumpVoltage;
 constexpr double Vacuum::kPumpHasPieceVoltage;
 constexpr aos::monotonic_clock::duration Vacuum::kTimeAtHigherVoltage;
-constexpr aos::monotonic_clock::duration Vacuum::kTimeToKeepPumpRunning;
+constexpr aos::monotonic_clock::duration Vacuum::kReleaseTime;
 
 void Vacuum::Iterate(const SuctionGoal *unsafe_goal, float suction_pressure,
                      SuperstructureQueue::Output *output, bool *has_piece,
                      aos::EventLoop *event_loop) {
   auto monotonic_now = event_loop->monotonic_now();
   bool low_pump_voltage = false;
-  bool no_goal_for_a_bit = false;
 
   // implement a simple low-pass filter on the pressure
   filtered_pressure_ = kSuctionAlpha * suction_pressure +
@@ -29,26 +28,31 @@
       monotonic_now > time_at_last_acquisition_ + kTimeAtHigherVoltage &&
       new_has_piece;
 
-  // if we've had the piece for enought time, go to lower pump_voltage
+  // If we've had the piece for enough time, go to lower pump_voltage
   low_pump_voltage = *has_piece;
-  no_goal_for_a_bit =
-      monotonic_now > time_at_last_evacuate_goal_ + kTimeToKeepPumpRunning;
 
   if (unsafe_goal && output) {
-    const bool evacuate = unsafe_goal->top || unsafe_goal->bottom;
-    if (evacuate) {
-      time_at_last_evacuate_goal_ = monotonic_now;
+    const bool release = !unsafe_goal->top && !unsafe_goal->bottom;
+
+    if (release) {
+      last_release_time_ = monotonic_now;
     }
 
     // Once the vacuum evacuates, the pump speeds up because there is no
     // resistance.  So, we want to turn it down to save the pump from
     // overheating.
     output->pump_voltage =
-        (no_goal_for_a_bit) ? 0 : (low_pump_voltage ? kPumpHasPieceVoltage
-                                                    : kPumpVoltage);
+        release ? 0 : (low_pump_voltage ? kPumpHasPieceVoltage : kPumpVoltage);
 
     output->intake_suction_top = unsafe_goal->top;
     output->intake_suction_bottom = unsafe_goal->bottom;
+
+    // If we intend to release, or recently released, set has_piece to false so
+    // that we give the part of the vacuum circuit with the pressure sensor time
+    // to equilibrate with the rest of the suction cup.
+    if (release || monotonic_now < last_release_time_ + kReleaseTime) {
+      *has_piece = false;
+    }
   }
   had_piece_ = new_has_piece;
 }
diff --git a/y2019/control_loops/superstructure/vacuum.h b/y2019/control_loops/superstructure/vacuum.h
index d2acf97..f0e97e9 100644
--- a/y2019/control_loops/superstructure/vacuum.h
+++ b/y2019/control_loops/superstructure/vacuum.h
@@ -1,8 +1,8 @@
 #ifndef Y2019_CONTROL_LOOPS_SUPERSTRUCTURE_VACUUM_H_
 #define Y2019_CONTROL_LOOPS_SUPERSTRUCTURE_VACUUM_H_
 
-#include "y2019/control_loops/superstructure/superstructure.q.h"
 #include "aos/controls/control_loop.h"
+#include "y2019/control_loops/superstructure/superstructure.q.h"
 
 namespace y2019 {
 namespace control_loops {
@@ -15,7 +15,6 @@
                SuperstructureQueue::Output *output, bool *has_piece,
                aos::EventLoop *event_loop);
 
-
   // Voltage to the vaccum pump when we are attempting to acquire a piece
   static constexpr double kPumpVoltage = 8.0;
 
@@ -26,13 +25,13 @@
   static constexpr aos::monotonic_clock::duration kTimeAtHigherVoltage =
       std::chrono::milliseconds(100);
 
-  // Time to continue the pump after getting a no suck goal
-  static constexpr aos::monotonic_clock::duration kTimeToKeepPumpRunning =
-      std::chrono::milliseconds(750);
+  // Time required for the game piece to be released from a vacuum
+  static constexpr aos::monotonic_clock::duration kReleaseTime =
+      std::chrono::milliseconds(250);
 
  private:
   bool had_piece_ = false;
-  aos::monotonic_clock::time_point time_at_last_evacuate_goal_ =
+  aos::monotonic_clock::time_point last_release_time_ =
       aos::monotonic_clock::epoch();
   aos::monotonic_clock::time_point time_at_last_acquisition_ =
       aos::monotonic_clock::epoch();
diff --git a/y2019/wpilib_interface.cc b/y2019/wpilib_interface.cc
index 221bb51..aa29bc9 100644
--- a/y2019/wpilib_interface.cc
+++ b/y2019/wpilib_interface.cc
@@ -383,10 +383,10 @@
         if (superstructure_.get()) {
           LOG_STRUCT(DEBUG, "solenoids", *superstructure_);
 
-          big_suction_cup0_->Set(superstructure_->intake_suction_top);
-          big_suction_cup1_->Set(superstructure_->intake_suction_top);
-          small_suction_cup0_->Set(superstructure_->intake_suction_bottom);
-          small_suction_cup1_->Set(superstructure_->intake_suction_bottom);
+          big_suction_cup0_->Set(!superstructure_->intake_suction_bottom);
+          big_suction_cup1_->Set(!superstructure_->intake_suction_bottom);
+          small_suction_cup0_->Set(superstructure_->intake_suction_top);
+          small_suction_cup1_->Set(superstructure_->intake_suction_top);
 
           intake_rollers_talon_->Set(
               ctre::phoenix::motorcontrol::ControlMode::PercentOutput,