Quadcopter‑Sim

Light‑weight, strictly‑typed Python toolkit for 6‑DoF quadrotor simulation, 3‑D plotting and step‑wise control loops — perfect for control‑systems classes, flight‑code prototyping or RL research.

Table of Contents

• Installation
• Quick Start
• Command Line Interface
• Core Features
• API Reference
• Usage Examples
• Examples & Notebooks
• Testing & Verification
• Academic Use
• Roadmap

---

Installation

# Latest release
pip install quadcopter-sim

# Development install with all optional dependencies
git clone https://github.com/2black0/quadcopter-sim-python
cd quadcopter-sim-python
pip install -e .[all]      # includes all optional dependencies for development

# Install specific optional dependencies
pip install -e .[rl]       # Gymnasium for RL
pip install -e .[control]  # SciPy for advanced control
pip install -e .[data]     # SciPy for data export
pip install -e .[dev]      # Core development tools (testing, linting)

---

Quick Start

Minimal Example

import numpy as np
from quadcopter.simulation import simulate, Params
from quadcopter.plotting import plot_trajectory

p = Params()
hover_speed = np.sqrt(p.m * p.g / (4 * p.b))          # rad/s

t, s, u = simulate(
    4.0, 0.02,
    controller=lambda *_: np.full(4, hover_speed),
    method="rk4",
)
plot_trajectory(t, s, u)

Command Line Usage

# Basic hover simulation with 3D plot
python -m quadcopter --plot

# PID position control
python -m quadcopter --controller pid --target-pos 1 1 2 --duration 10 --plot

---

Command Line Interface

The package provides a comprehensive command-line interface for simulation, control, and analysis:

Basic Usage Examples

# Basic hover simulation
python -m quadcopter --plot               # 4 s hover + 3‑D figure
python -m quadcopter --duration 6 --csv run.csv --quiet

# PID position control
python -m quadcopter --controller pid --target-pos 1 1 2 --duration 10 --plot

# LQR control with custom parameters
python -m quadcopter --controller lqr --duration 5 --plot

# Academic analysis and logging
python -m quadcopter --controller pid --target-pos 1 1 2 --duration 10 --academic-log results

# Advanced PID tuning
python -m quadcopter --controller pid --target-pos 1 0 1 --duration 5 \
  --pid-kp 3 3 5 --pid-ki 0.2 0.2 0.3 --pid-kd 0.6 0.6 1.2 \
  --plot

# Custom initial conditions
python -m quadcopter --controller pid --target-pos 0 0 2 --duration 5 \
  --init-pos 0 0 1 --init-vel 0 0 0.5 \
  --csv trajectory.csv --json log.json --matlab data.mat

# Enhanced plotting options
python -m quadcopter --controller pid --target-pos 1 1 2 --duration 10 --plot-errors
python -m quadcopter --controller pid --target-pos 1 1 2 --duration 10 --plot-comparison

CLI Options Reference

usage: python -m quadcopter [-h] [--duration DURATION] [--dt DT]
                            [--method {rk45,rk4}] [--rtol RTOL] [--atol ATOL]
                            [--controller {hover,pid,lqr}]
                            [--pid-kp PID_KP PID_KP PID_KP]
                            [--pid-ki PID_KI PID_KI PID_KI]
                            [--pid-kd PID_KD PID_KD PID_KD]
                            [--target-pos TARGET_POS TARGET_POS TARGET_POS]
                            [--plot] [--csv CSV] [--json JSON]
                            [--matlab MATLAB] [--academic-log ACADEMIC_LOG]
                            [--controller-type {pid,lqr,rl}]
                            [--init-pos INIT_POS INIT_POS INIT_POS]
                            [--init-vel INIT_VEL INIT_VEL INIT_VEL] [--quiet]
                            [--verbose]

Comprehensive quadcopter simulation and analysis tool.

Simulation Parameters:
  --duration DURATION       simulation time [s]
  --dt DT                   integration step [s]
  --method {rk45,rk4}       integration method (adaptive RK45 or fixed‑step RK4)
  --rtol RTOL               solver rtol
  --atol ATOL               solver atol

Controller Options:
  --controller {hover,pid,lqr}    controller type to use
  --pid-kp PID_KP PID_KP PID_KP   PID Kp gains for x, y, z axes
  --pid-ki PID_KI PID_KI PID_KI   PID Ki gains for x, y, z axes
  --pid-kd PID_KD PID_KD PID_KD   PID Kd gains for x, y, z axes
  --target-pos TARGET_POS TARGET_POS TARGET_POS  target position [x, y, z]

Initial Conditions:
  --init-pos INIT_POS INIT_POS INIT_POS    initial position [x, y, z]
  --init-vel INIT_VEL INIT_VEL INIT_VEL    initial velocity [vx, vy, vz]

Output Options:
  --plot                    show matplotlib figure
  --csv CSV                 save (t, state, control) to CSV
  --json JSON               save simulation log to JSON
  --matlab MATLAB           save simulation log to MATLAB .mat file
  --academic-log ACADEMIC_LOG    enable academic logging and save to directory
  --quiet                   suppress info output
  --verbose                 enable verbose output

---

Core Features

1. Advanced Control Systems

Comprehensive control system implementations:

from quadcopter.controllers import PIDController, PositionController, LQRController

# PID Position Control
position_ctrl = PositionController(
    x_pid=PIDController(kp=2.0, ki=0.1, kd=0.5),
    y_pid=PIDController(kp=2.0, ki=0.1, kd=0.5),
    z_pid=PIDController(kp=4.0, ki=0.2, kd=1.0),
    target_pos=np.array([1.0, -1.0, 2.0])
)

# LQR Control
A = np.eye(12)  # State matrix
B = np.eye(12, 4)  # Input matrix
lqr_ctrl = LQRController(A=A, B=B, Q=np.eye(12), R=np.eye(4))

2. Reinforcement Learning Integration

Gymnasium-compatible environment for RL research:

from quadcopter.gym_env import QuadcopterGymEnv

env = QuadcopterGymEnv()
obs, info = env.reset()
action = env.action_space.sample()  # Random action
obs, reward, terminated, truncated, info = env.step(action)

3. Real-time Simulation

Enhanced environment with real-time capabilities:

from quadcopter.env import RealTimeQuadcopterEnv

# Run simulation at half real-time speed
env = RealTimeQuadcopterEnv(dt=0.02, real_time_factor=0.5)

4. Comprehensive Logging

Advanced logging with multiple export formats:

from quadcopter.logging import simulate_with_logging

log = simulate_with_logging(duration=5.0, dt=0.02, controller=my_controller)
log.save_csv("simulation.csv")      # CSV for analysis
log.save_json("simulation.json")    # JSON for structured data
log.save_matlab("simulation.mat")   # MATLAB for advanced analysis

5. Academic Evaluation and Visualization

Comprehensive academic evaluation tools for research publications:

from quadcopter.logging import simulate_with_academic_logging
from quadcopter.evaluation import AcademicEvaluator

# Run simulation with academic logging
log = simulate_with_academic_logging(
    duration=10.0, 
    dt=0.02, 
    controller=my_controller,
    ref_position=np.array([1.0, -1.0, 2.0]),
    controller_type="pid"
)

# Create academic evaluator
evaluator = AcademicEvaluator(log)

# Generate comprehensive analysis
metrics = evaluator.generate_comprehensive_analysis("results")

# Generate specific plots
evaluator.plot_3d_trajectory("trajectory.png")
evaluator.plot_state_tracking("tracking.png")
evaluator.plot_error_analysis("errors.png")
evaluator.plot_control_effort("control.png")

6. Enhanced Visualization

Comprehensive plotting capabilities:

from quadcopter.plotting import (
    plot_trajectory, 
    plot_control_errors, 
    plot_3d_trajectory_comparison,
    plot_frequency_analysis
)

# Control error analysis
plot_control_errors(t, states, targets)

# Trajectory comparison
plot_3d_trajectory_comparison([
    (states1, "Controller A"),
    (states2, "Controller B")
])

# Frequency domain analysis
plot_frequency_analysis(t, signals, ["X Position", "Y Position", "Z Position"])

---

API Reference

Function / Class	Purpose	Key Arguments
Core Simulation
quadcopter.simulation.simulate	One‑shot trajectory generator (adaptive RK45 or fixed‑step RK4)	duration, dt, controller, method
quadcopter.dynamics.Params	Physical constants (mass, arm length, thrust factor)	edit attributes to match your air‑frame
quadcopter.dynamics.QuadState	Minimal dataclass for the 13‑dim state	.from_vector(vec) / .as_vector()
Environments
quadcopter.env.QuadcopterEnv	Real‑time, fixed‑step RK4 environment	dt, reset(), step()
quadcopter.env.RealTimeQuadcopterEnv	Real-time environment with timing control	dt, real_time_factor, reset(), step()
quadcopter.gym_env.QuadcopterGymEnv	Gymnasium-compatible environment for RL training	dt, max_steps
Controllers
quadcopter.controllers.PIDController	PID controller with anti-windup and output limits	kp, ki, kd, max_output
quadcopter.controllers.PositionController	3D position controller using PID for each axis	x_pid, y_pid, z_pid, target_pos
quadcopter.controllers.LQRController	Linear Quadratic Regulator controller	A, B, Q, R matrices
Logging & Analysis
quadcopter.logging.SimulationLog	Comprehensive logging with multiple export formats	save_csv(), save_json(), save_matlab()
quadcopter.logging.AcademicLog	Academic-grade logging for research publications	add_entry(), save_csv(), save_json(), save_matlab()
quadcopter.logging.simulate_with_academic_logging	Simulation with academic-grade logging	duration, dt, controller, ref_position
quadcopter.evaluation.AcademicEvaluator	Academic evaluation tools for performance analysis	plot_3d_trajectory(), plot_state_tracking(), generate_performance_report()
Visualization
quadcopter.plotting.plot_trajectory	Static 3‑D + time‑series figure	t, states, controls
quadcopter.plotting.plot_control_errors	Control error analysis over time	t, states, targets
quadcopter.plotting.plot_3d_trajectory_comparison	Compare multiple trajectories in 3D	trajectories
quadcopter.plotting.plot_frequency_analysis	Frequency domain analysis of signals	t, signals, signal_names
quadcopter.plotting.animate_trajectory	Matplotlib animation (MP4 / Jupyter)	t, states, fps, save_path
Utilities
quadcopter.utils.create_pid_position_controller	Create PID position controller with default gains	target_pos, kp, ki, kd
quadcopter.utils.create_pid_attitude_controller	Create PID attitude controller with default gains	target_attitude, kp, ki, kd
quadcopter.utils.create_lqr_controller	Create LQR controller with default matrices	params, Q, R
quadcopter.utils.create_hover_controller	Create simple hover controller	params

---

Usage Examples

1. Simplified PID Position Control

from quadcopter import simulate, create_pid_position_controller
from quadcopter.dynamics import QuadState
from quadcopter.plotting import plot_trajectory
import numpy as np

# Create position controller using utility function
controller = create_pid_position_controller(
    target_pos=[1.0, -1.0, 2.0],
    kp=(2.0, 2.0, 4.0),
    ki=(0.1, 0.1, 0.2),
    kd=(0.5, 0.5, 1.0)
)

# Set up initial state
initial_state = QuadState(
    pos=np.array([0.0, 0.0, 0.0]),
    vel=np.array([0.0, 0.0, 0.0]),
    quat=np.array([1.0, 0.0, 0.0, 0.0]),
    ang_vel=np.array([0.0, 0.0, 0.0])
)

# Run simulation
t, states, controls = simulate(
    duration=10.0,
    dt=0.02,
    controller=controller,
    initial_state=initial_state,
    method="rk4"
)

# Plot results
plot_trajectory(t, states, controls)

2. Advanced PID Position Control

from quadcopter import simulate, PositionController, PIDController
from quadcopter.dynamics import QuadState
from quadcopter.plotting import plot_trajectory
import numpy as np

# Create position controller
controller = PositionController(
    x_pid=PIDController(kp=2.0, ki=0.1, kd=0.5),
    y_pid=PIDController(kp=2.0, ki=0.1, kd=0.5),
    z_pid=PIDController(kp=4.0, ki=0.2, kd=1.0),
    target_pos=np.array([1.0, -1.0, 2.0])
)

# Set up initial state
initial_state = QuadState(
    pos=np.array([0.0, 0.0, 0.0]),
    vel=np.array([0.0, 0.0, 0.0]),
    quat=np.array([1.0, 0.0, 0.0, 0.0]),
    ang_vel=np.array([0.0, 0.0, 0.0])
)

# Run simulation
t, states, controls = simulate(
    duration=10.0,
    dt=0.02,
    controller=controller,
    initial_state=initial_state,
    method="rk4"
)

# Plot results
plot_trajectory(t, states, controls)

3. Reinforcement Learning

from quadcopter.gym_env import QuadcopterGymEnv
import numpy as np

# Create RL environment
env = QuadcopterGymEnv()

# Simple policy
def simple_policy(observation):
    # Simple hover policy
    hover_speed = np.sqrt(0.65 * 9.81 / (4 * 3.25e-5))
    return np.full(4, hover_speed)

# Training loop
obs, info = env.reset()
for _ in range(1000):
    action = simple_policy(obs)
    obs, reward, terminated, truncated, info = env.step(action)
    if terminated or truncated:
        obs, info = env.reset()

4. Real-time Simulation

from quadcopter.env import RealTimeQuadcopterEnv
import numpy as np

# Create real-time environment (half speed)
env = RealTimeQuadcopterEnv(dt=0.02, real_time_factor=0.5)
obs = env.reset()

# Simple hover controller
hover_speed = np.sqrt(0.65 * 9.81 / (4 * 3.25e-5))
motor_speeds = np.full(4, hover_speed)

# Run simulation
for _ in range(200):  # 4 seconds
    obs = env.step(motor_speeds)
    print(f"t={obs['t'][0]:.2f}s, pos={obs['pos']}")

print("Simulation completed!")

5. Comprehensive Logging

from quadcopter.logging import simulate_with_logging
from quadcopter.controllers import PositionController, PIDController
import numpy as np

# Create controller
controller = PositionController(
    x_pid=PIDController(kp=2.0, ki=0.1, kd=0.5),
    y_pid=PIDController(kp=2.0, ki=0.1, kd=0.5),
    z_pid=PIDController(kp=4.0, ki=0.2, kd=1.0),
    target_pos=np.array([1.0, -1.0, 2.0])
)

# Run simulation with logging
log = simulate_with_logging(
    duration=5.0,
    dt=0.02,
    controller=controller,
    method="rk4"
)

# Export data in multiple formats
log.save_csv("trajectory_data.csv")
log.save_json("trajectory_data.json")
log.save_matlab("trajectory_data.mat")

6. Academic Evaluation

from quadcopter.logging import simulate_with_academic_logging
from quadcopter.evaluation import AcademicEvaluator
from quadcopter.controllers import PositionController, PIDController
from quadcopter.dynamics import QuadState
import numpy as np

# Create position controller
controller = PositionController(
    x_pid=PIDController(kp=2.0, ki=0.1, kd=0.5),
    y_pid=PIDController(kp=2.0, ki=0.1, kd=0.5),
    z_pid=PIDController(kp=4.0, ki=0.2, kd=1.0),
    target_pos=np.array([1.0, -1.0, 2.0])
)

# Set up initial state
initial_state = QuadState(
    pos=np.array([0.0, 0.0, 0.0]),
    vel=np.array([0.0, 0.0, 0.0]),
    quat=np.array([1.0, 0.0, 0.0, 0.0]),
    ang_vel=np.array([0.0, 0.0, 0.0])
)

# Run simulation with academic logging
log = simulate_with_academic_logging(
    duration=10.0,
    dt=0.02,
    controller=controller,
    initial_state=initial_state,
    ref_position=np.array([1.0, -1.0, 2.0]),
    controller_type="pid"
)

# Create academic evaluator
evaluator = AcademicEvaluator(log)

# Generate comprehensive analysis with all plots and metrics
metrics = evaluator.generate_comprehensive_analysis("academic_results")

print("Academic evaluation completed! Results saved to 'academic_results' directory.")

---

Examples & Notebooks

The library includes comprehensive examples demonstrating various features:

Python Examples

Run any example with: python examples/<example_name>.py

• pid_control_example.py - PID position control demonstration
• lqr_control_example.py - LQR control implementation
• rl_training_example.py - Reinforcement learning training
• real_time_simulation.py - Real-time simulation with timing
• enhanced_plotting_example.py - Advanced visualization techniques
• enhanced_logging_example.py - Comprehensive data logging
• academic_evaluation_example.py - Academic evaluation and analysis

Jupyter Notebooks

Run any notebook with: jupyter notebook notebooks/<notebook_name>.ipynb

• control_system_design.ipynb - Interactive PID/LQR tuning
• rl_training_tutorial.ipynb - RL experimentation and analysis
• data_analysis.ipynb - Log analysis and visualization
• performance_comparison.ipynb - Comparing different control methods

---

Testing & Verification

pytest -q                        # Unit + performance tests (should be all dots)
mypy quadcopter                  # Static typing gate (should be 'Success')
python -m quadcopter --quiet     # CLI smoke test

All three commands should finish without errors. A 4s RK4 simulation typically takes ≈ 0.05–0.08s on a 2020‑era laptop.

---

Academic Use

This library is designed for academic research and education. When using in research publications, please cite:

@software{quadcopter_dynamics_2025,
  author = {2black0},
  title = {Quadcopter-Sim: A Python Toolkit for 6-DoF Quadrotor Simulation},
  year = {2025},
  doi = {TBD},
  url = {https://github.com/2black0/quadcopter-sim-python}
}

---

Roadmap

✅ Completed Features:

• Advanced control systems (PID, LQR, Fuzzy Logic)
• Gymnasium‑compatible wrapper for RL training
• Comprehensive logging for academic research
• Real-time simulation capabilities
• Enhanced visualization and analysis tools
• Academic evaluation and analysis tools for research publications
• Optional aerodynamic drag model
• Notebook benchmark for tuning PID / LQR / MPC / RL policies

🚧 Future Development:

• More controller types (MPC, Sliding Mode, etc.)
• Advanced disturbance models
• Multi-agent simulation capabilities
• Integration with hardware-in-the-loop testing

---

Released under the MIT License. Contributions and issues are very welcome!