AP1 Basic Vehicle Simulation

This package simulates a small car model that connects to the Control Node.
It’s used to test basic motion without needing the full planning stack. YET! More to come with that later...

Overview

The Control Node publishes:

• /motor_power → throttle command (0–1)
• /turn_angle → steering command (radians)

The Sim Node (SimNode) subscribes to those and publishes:

• /vehicle_speed → current speed (m/s)
• /vehicle_position → current position (x, y, z)

Key Parameters in sim_node.hpp

Field	Meaning	Effect if Increased
mass_kg	Vehicle mass	Slower acceleration
max_force_n	Engine power	Faster acceleration, higher top speed
drag_coeff	Air/rolling resistance	Lower top speed, stronger deceleration
wheelbase_m	Distance between axles	Wider turns
max_steer_rad	Max steering angle (radians)	Tighter turns

Changes Made for Control Connection

In ControlNode

• Added publishers:

  turning_angle_pub_ = this->create_publisher<std_msgs::msg::Float32>("turn_angle", 10);
  motor_power_pub_ = this->create_publisher<std_msgs::msg::Float32>("motor_power", 10);
  
  

• Added a test timer that publishes throttle=0.5, steer=0.0 every 100ms:

  test_timer_ = this->create_wall_timer(
      100ms,
      std::bind(&ControlNode::on_test_timer, this)
  );

In Sim_Node

• Subscribed to:

  "motor_power"  // throttle
  "turn_angle"   // steering

• Publishes simulated state on:

  "vehicle_speed"
  "vehicle_position"

How to Build and Run

Build:

colcon build --packages-select ap1_control ap1_pnc_sim
source install/setup.bash

Then run:

ros2 run ap1_pnc_sim pnc_sim_node

You can echo output like so:

ros2 topic echo /vehicle_speed
ros2 topic echo /vehicle_position

You should see the car moving forward in the sim (x increasing, y≈0).