Project: Autonomous Ski Lift Simulation for Safety & Efficiency (C example)

examples/C/src/SkiLift/Lift.lf

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+/**
+ * This project simulates the behavior of ski lifts with a focus on improving safety and reducing
+ * labor costs through automation using Lingua Franca. The simulation models key aspects of ski lift
+ * operations, including:
+ *
+ * 1. Passenger Flow & Lift Capacity: Ensuring smooth and efficient boarding/unboarding.
+ *
+ * 2. Safety Mechanisms: Detecting potential dangers and automating responses to prevent accidents.
+ *
+ * 3. Autonomous Control: Optimizing lift operations with minimal human intervention.
+ *
+ * The goal is to explore how automation can enhance safety while reducing operational costs, making
+ * ski lifts more efficient and reliable.
+ *
+ * @author Cheng Yen, Tsai
+ */
+target C
+
+import EntryGate from "lib/EntryGate.lf"
+import EntrySensor from "lib/EntrySensor.lf"
+import LiftSensor from "lib/LiftSensor.lf"
+import ObjectDetector from "lib/ObjectDetector.lf"
+import ScreenPrinter from "lib/ScreenPrinter.lf"
+import LiftMotion from "lib/LiftMotion.lf"
+
+main reactor Lift {
+  state move: bool = true
+  state open: bool = false
+  state stay_cur_mode: bool = true
+  state count: int32_t = 0
+  state start_number: int32_t = 0
+  state end_number: int32_t = 0
+  state screen_wideth: int32_t = 80
+  state passenger_cnt: int32_t = 0
+  liftMotion = new LiftMotion()
+  entryGate = new EntryGate()
+  entrySensor = new EntrySensor()
+  liftSensor = new LiftSensor()
+  objectDetector = new ObjectDetector()
+  screenPrinter = new ScreenPrinter()
+
+  timer t(500 msec, 500 msec)
+
+  state gate_t_counter: int32_t = 0
+  state offset: int32_t = 0
+  timer t_gate(0, 1 sec)
+
+  // Start the program (When staff press the start button of the lift)
+  reaction(startup) -> screenPrinter.offset, screenPrinter.motion_msg {=
+    lf_set(screenPrinter.offset, self->offset);
+    lf_set(screenPrinter.motion_msg, "Moving");
+    self->offset = (self->offset + 1) % self->screen_wideth; // Update the offset for the next frame
+  =}
+
+  reaction(objectDetector.start_number) {=
+    if (objectDetector.start_number != 0) {
+      self->start_number = objectDetector.start_number->value;
+    }
+  =}
+
+  reaction(t) -> liftMotion.move, liftMotion.offset {=
+    self->count++;
+    if (self->count % 10 == 0) {
+      self->move = !self->move;
+    } else {
+      self->offset = (self->offset + 1) % self->screen_wideth; // Update the offset for the next frame
+    }
+
+    lf_set(liftMotion.move, self->move);
+    lf_set(liftMotion.offset, self->offset);
+  =}
+
+  reaction(t_gate) -> entryGate.open, screenPrinter.gate_msg {=
+    if (self->gate_t_counter % 4 == 0) {
+      self->open = true;
+      lf_set(entryGate.open, self->open);
+      lf_set(screenPrinter.gate_msg, "Open");
+    } else if (self->gate_t_counter % 4 == 1) {
+      self->open = false;
+      lf_set(entryGate.open, self->open);
+      lf_set(screenPrinter.gate_msg, "Close");
+    }
+    self->gate_t_counter ++;
+  =}
+
+  reaction(entrySensor.gate_1) {=
+    if (entrySensor.gate_1->value) {
+      self->passenger_cnt ++;
+    }
+  =}
+
+  reaction(entrySensor.gate_2) {=
+    if (entrySensor.gate_2->value) {
+      self->passenger_cnt ++;
+    }
+  =}
+
+  reaction(entrySensor.gate_3) {=
+    if (entrySensor.gate_3->value) {
+      self->passenger_cnt ++;
+    }
+  =}
+
+  reaction(objectDetector.end_number) {=
+    if (objectDetector.end_number != 0) {
+      self->end_number = objectDetector.end_number->value;
+    }
+  =}
+}

examples/C/src/SkiLift/Readme.md

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+
+<h1 align="center">
+  <br>
+  <img src="assets/cable-car-solid.svg" alt="Markdownify" width="200">
+  <br>
+  <br>
+  Autonomous Ski Lift System
+  <br>
+</h1>
+
+<h4 align="center">A safe and efficient ski lift system build with <a href="https://www.lf-lang.org/" target="_blank">Lingua Franca</a>.</h4>
+
+<br>
+
+<div display="block" align="center">
+<video width="600" controls>
+  <source src="assets/demo.mov" type="video/mp4">
+  Your browser does not support the video tag.
+</video>
+</div>
+
+
+## About the Project
+
+This project simulates the behavior of ski lifts with a focus on improving safety and reducing labor costs through automation using Lingua Franca. The simulation models key aspects of ski lift operations, including:
+
+1. **Passenger Flow & Lift Capacity**
+    - Ensuring smooth and efficient boarding/unboarding.
+2. **Safety Mechanisms**
+    - Detecting potential dangers and automating responses to prevent accidents.
+3. **Autonomous Control**
+    - Optimizing lift operations with minimal human intervention.
+
+The goal is to explore how automation can enhance safety while reducing operational costs, making ski lifts more efficient and reliable.
+
+## How To Use
+
+To clone and run this application, you'll need [Git](https://git-scm.com) and [Lingua Franca](https://www.lf-lang.org/docs/installation) installed on your computer. From your command line:
+
+```bash
+# Clone this repository
+$ git clone https://github.com/lf-lang/playground-lingua-franca.git
+
+# Go into the example folder of the repository
+$ cd playground-lingua-franca/examples/C
+
+# Compile the main reactor
+$ lfc src/SkiLift/Lift.lf
+
+# Run the program
+$ bin/Lift
+```
+
+> **Note:**
+> Or you can compile and run the program simply using VS Code, [see section "Running Locally"](https://github.com/lf-lang/playground-lingua-franca).
+
+
+## Components (Reactors)
+
+<table>
+<tr>
+<td> <img src="assets/Lift.png" alt="Lift" width="400">
+<td> <a href="Lift.lf">Lift.lf</a>: The main reactor that controls all timed and startup events, receives signals from sensors, and manages the lift behavior.</td>
+</tr>
+<tr>
+<td> <img src="assets/EntryGate.png" alt="EntryGate" width="400">
+<td> <a href="lib/EntryGate.lf">EntryGate.lf</a>: Uses a modal model to control the opening and stopping of the entry gate.</td>
+</tr>
+<tr>
+<td> <img src="assets/ScreenPrinter.png" alt="ScreenPrinter" width="400">
+<td> <a href="lib/ScreenPrinter.lf">ScreenPrinter.lf</a>: Manages stdout behavior for the ski lift simulation. This reactor handles printing lift animations, clearing lines, and refreshing the displayed output to ensure smooth and dynamic visualization.</td>
+</tr>
+<tr>
+<td> <img src="assets/EntrySenor.png" alt="EntrySensor" width="400">
+<td> <a href="lib/EntrySensor.lf">EntrySensor.lf</a>: Processes data from the sensor placed at the entry gate. This reactor tracks the number of people attempting to board the lift, ensuring accurate passenger flow management.</td>
+</tr>
+<tr>
+<td> <img src="assets/LiftSensor.png" alt="LiftSensor" width="400">
+<td>
+    <a href="lib/LiftSensor.lf">LiftSensor.lf</a>:  Processes data from two sensors—one at the start of the lift and one at the end.
+    <ul>
+        <li><strong>Start sensor:</strong> Detects when a lift chair is ready to carry passengers in the ready area. If triggered, it signals the gate to open, allowing the next group of passengers to board.</li>
+        <li><strong>End sensor:</strong> Detects when a lift chair reaches the unloading area. If triggered, it checks whether any passengers remain in the exit area, ensuring a smooth and safe unloading process.</li>
+    </ul>
+</td>
+</tr>
+<tr>
+<td> <img src="assets/ObjectDetector.png" alt="ObjectDetector" width="400">
+<td> <a href="lib/ObjectDetector.lf">ObjectDetector.lf</a>: Detects the number of people on the ready and exit areas.</td>
+</tr>
+<tr>
+<td> <img src="assets/LiftMotion.png" alt="LiftMotion" width="400">
+<td> <a href="lib/LiftMotion.lf">LiftMotion.lf</a>: Uses a modal model to control the motion of the lift.</td>
+</tr>
+</table>
+
+

examples/C/src/SkiLift/lib/EntryGate.lf

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+/**
+ * @author Cheng Yen, Tsai
+ */
+target C
+
+
+reactor EntryGate {
+  input open: bool  // Toggle mode
+
+  mode OPEN {
+    reaction(open) -> reset(CLOSE) {=
+      if (open->value) {
+        lf_set_mode(CLOSE);
+      }
+    =}
+  }
+
+  initial mode CLOSE {
+    reaction(open) -> reset(OPEN) {=
+      if (!open->value) {
+        lf_set_mode(OPEN);
+      }
+    =}
+  }
+}

examples/C/src/SkiLift/lib/EntrySensor.lf

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+/**
+ * @author Cheng Yen, Tsai
+ */
+target C
+
+preamble {=
+  #include <time.h>
+  #include <stdbool.h>
+  #include <stdlib.h>
+=}
+reactor EntrySensor {
+  preamble {=
+    int random_bool() {
+      srand((unsigned int)time(NULL));
+      double true_probability = 0.8;
+      double random_value = (double)rand() / RAND_MAX;
+      if (random_value < true_probability) {
+        return 1;
+      }
+      return 0;
+    };
+  =}
+  output gate_1: bool
+  output gate_2: bool
+  output gate_3: bool
+
+  timer t(0, 200 msec);
+  reaction(t) -> gate_1, gate_2, gate_3 {=
+    lf_set(gate_1, random_bool());
+    lf_set(gate_2, random_bool());
+    lf_set(gate_3, random_bool());
+  =}
+}

examples/C/src/SkiLift/lib/LiftMotion.lf

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+target C
+import ScreenPrinter from "ScreenPrinter.lf"
+reactor LiftMotion {
+  input move: bool  // Toggle mode
+  input offset: int32_t
+  screenPrinter = new ScreenPrinter()
+
+  initial mode MOVING {
+    reaction(move, offset) ->
+    reset(MOVING), reset(STOPPED), screenPrinter.motion_msg, screenPrinter.offset {=
+      if (move->value) {
+        lf_set(screenPrinter.offset, offset->value);
+        lf_set_mode(MOVING);
+      } else {
+        lf_set_mode(STOPPED);
+        lf_set(screenPrinter.motion_msg ,"Stop");
+      }
+    =}
+  }
+
+  mode STOPPED {
+    reaction(move) -> reset(MOVING), reset(STOPPED), screenPrinter.motion_msg {=
+      if (!move->value) {
+        lf_set_mode(STOPPED);
+      } else {
+        lf_set_mode(MOVING);
+        lf_set(screenPrinter.motion_msg ,"Moving");
+      }
+    =}
+  }
+}

examples/C/src/SkiLift/lib/LiftSensor.lf

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+/**
+ * @author Cheng Yen, Tsai
+ */
+target C
+
+reactor LiftSensor {
+  output start_ready: bool
+  output end_ready: bool
+
+  reaction(startup) -> start_ready, end_ready {=
+    lf_set(start_ready, true);
+    lf_set(end_ready, true);
+  =}
+}

examples/C/src/SkiLift/lib/ObjectDetector.lf

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+/**
+ * @author Cheng Yen, Tsai
+ */
+target C
+
+reactor ObjectDetector {
+  output start_number: int32_t
+  output end_number: int32_t
+
+  reaction(startup) -> start_number, end_number {=
+    lf_set(start_number, 3);
+    lf_set(end_number, 3);
+  =}
+}