ros2-assignments/doc/architecture/nodes/IMUDataSimulator.md

IMUDataSimulator (assignments::three::data_simulator_node)

The IMUDataSimulator node generates simulated IMU sensor data (sensor_msgs/msg/Imu) based on configurable time-varying intervals. It publishes linear acceleration and angular velocity values that can follow constant, linear, or quadratic trajectories over time.

Implementation Details

Parameters

Parameter	Type	Default	Description
publish_rate	double	10.0	Publishing frequency in Hz
max_intervals	int	4	Maximum number of intervals per axis
<axis>.num_intervals	int	0	Number of intervals for each axis
<axis>.interval_<n>.*	various	-	Interval configuration (see Simulator)

Axes Configured:

• linear_x, linear_y, linear_z - Linear acceleration axes
• angular_x, angular_y, angular_z - Angular velocity axes

Constructor

DataSimulator()

• Initializes ROS2 node with name imu_data_simulator
• Creates Simulator instance for value generation
• Creates publisher for simulated_imu_data topic
• Sets up timer for periodic publishing

Core Functionality

void publish_imu_data()

• Timer callback invoked at the configured publish rate
• Calculates elapsed time since node start
• Queries Simulator for current values of all 6 axes
• Populates IMU message with:
  • Header timestamp and frame_id (imu_link)
  • Linear acceleration (x, y, z)
  • Angular velocity (x, y, z)
• Publishes message to topic

ROS2 Interface

Publications

• simulated_imu_data (sensor_msgs/msg/Imu)
  • Publishes simulated IMU data at configured rate
  • Frame ID: imu_link

Usage Example

ros2 run g2_2025_odometry_pkg imu_data_simulator_node --ros-args \
  -p publish_rate:=20.0 \
  -p linear_x.num_intervals:=1 \
  -p linear_x.interval_0.type:=constant \
  -p linear_x.interval_0.t_start:=0.0 \
  -p linear_x.interval_0.t_end:=10.0 \
  -p linear_x.interval_0.y_start:=9.81

Dependencies

• rclcpp - ROS2 C++ client library
• sensor_msgs - Standard sensor message types
• Simulator - Internal simulation engine