EN | JP | Last sync: 2026-01

Chapter 2: Planning, Control, and Key Players

Decision-Making Algorithms, Vehicle Control Systems, and the Autonomous Driving Industry Landscape

Reading Time: 90-100 minutes Difficulty: Intermediate

This chapter covers the planning and control layers of the autonomous driving stack, from classical path planning algorithms to modern End-to-End neural architectures. We then survey the major industry players shaping the autonomous driving landscape as of early 2026, including their technologies, deployment status, and strategic directions.

Learning Objectives

By completing this chapter, you will be able to:


4. Planning Technologies

Planning is the "brain" of an autonomous vehicle, responsible for deciding where to go and how to get there safely and efficiently. This section covers the three core planning sub-problems: path planning, behavior prediction, and decision-making, along with the critical architectural debate between modular and End-to-End approaches.

4.1 Path Planning

Path planning computes a feasible trajectory from the vehicle's current position to a goal, considering obstacles, road geometry, traffic rules, and dynamic constraints. Approaches fall into three broad categories: traditional (algorithmic), machine learning-based, and hybrid methods.

Traditional Methods

Graph-based methods discretize the environment into a graph of nodes and edges, then search for optimal paths:

Sampling-based methods explore the configuration space through random sampling, making them effective in high-dimensional or complex environments:

Optimization-based methods formulate path planning as a continuous optimization problem, minimizing a cost function (e.g., path length, curvature, jerk) subject to vehicle kinematic and dynamic constraints.

Interpolation curves generate smooth, drivable paths from waypoints:

ML-Based Methods

Machine learning-based path planning (approximately 25% of recent research) leverages learned representations for:

Hybrid Methods

Hybrid approaches (approximately 27% of recent research, and the latest trend) combine the strengths of multiple method families:

Comparison of Path Planning Approaches

Aspect Traditional (Graph/Sampling/Optimization) ML-Based Hybrid
Share of Research ~48% ~25% ~27% (growing)
Optimality Provable (A*, RRT*) No formal guarantees Partial guarantees
Adaptability Limited to hand-designed rules Learns from data Best of both worlds
Real-time Performance Varies (optimization can be slow) Fast inference Moderate to fast
Interpretability High Low (black box) Moderate
Safety Guarantees Formal verification possible Difficult to verify Partial verification
Data Requirements None Large-scale driving data Moderate
Handling Dynamic Obstacles D* (replanning), moderate Strong (learned patterns) Strong
Example Methods A*, RRT*, Spline, Bezier NN planners, RL planners NN cost map + A*, learned + optimization

4.2 Behavior Prediction

Behavior prediction forecasts the future trajectories and intentions of surrounding traffic participants (vehicles, pedestrians, cyclists). Accurate prediction is essential for safe planning, as the ego vehicle must anticipate others' movements to avoid collisions and navigate smoothly.

Physics Model-Based Prediction

Probability Distribution-Based Prediction

Deep Learning-Based Prediction

Reinforcement Learning-Based Prediction

4.3 Decision-Making Algorithms

Decision-making determines the high-level driving strategy: when to change lanes, how to navigate intersections, when to yield, and how to respond to unexpected situations.

Knowledge-Driven Approaches

Data-Driven Approaches

Hybrid Approaches: The 2025 Mainstream

The integration of knowledge-driven and data-driven methods represents the mainstream approach in 2025. Hybrid systems use rule-based components for safety-critical decisions (e.g., hard braking, emergency maneuvers) while leveraging learned components for nuanced decisions (e.g., comfortable lane-change timing, social navigation). This architecture provides both the reliability of explicit rules and the adaptability of learned behaviors.

4.4 End-to-End vs. Modular Architectures

The fundamental architectural choice in autonomous driving is between modular (pipeline) and End-to-End (E2E) approaches. This debate has intensified as deep learning capabilities have grown.

Architecture Comparison

Aspect Modular (Pipeline) End-to-End (E2E)
Structure Perception, Prediction, Planning, and Control are independently designed modules connected in sequence A single neural network maps sensor inputs directly to control outputs (steering, throttle, brake)
Advantages High interpretability; each module can be independently developed, tested, and debugged; clear failure attribution; leverages domain expertise Minimized information loss between stages; globally optimized for the driving task; no hand-designed interfaces between modules
Disadvantages Cumulative errors propagate through the pipeline; information loss at module interfaces; complex integration; suboptimal global performance Black box problem; difficult to debug failures; requires massive training data; safety verification is challenging

2025-2026 Frontier: Beyond the Binary Choice

The latest research transcends the simple modular vs. E2E dichotomy, introducing architectures that combine the benefits of both:

Vision-Language-Action (VLA) Models

LLM-Based Decision Making

Diffusion Model Planning

Sparse Representation Approaches


5. Control Technologies

Control is the final layer of the autonomous driving stack, translating planned trajectories into actual vehicle commands (steering angle, throttle, brake pressure). The control system must execute the planned path accurately while maintaining vehicle stability and passenger comfort.

5.1 PID Control

PID (Proportional-Integral-Derivative) control is the most fundamental and widely used feedback control method. It computes a control signal based on three terms derived from the tracking error $e(t)$:

The PID control law is expressed as:

$$u(t) = K_p e(t) + K_i \int_0^t e(\tau) \, d\tau + K_d \frac{de(t)}{dt}$$

where:

graph LR R["Reference
r(t)"] --> SUM(("+−")) SUM --> E["e(t)"] E --> P["K_p · e(t)
Proportional"] E --> I["K_i · ∫e dτ
Integral"] E --> D["K_d · de/dt
Derivative"] P --> ADD(("+")) I --> ADD D --> ADD ADD --> U["u(t)
Control Output"] U --> PLANT["Vehicle
Plant"] PLANT --> Y["y(t)
Output"] Y --> |Feedback| SUM

Advantages

Disadvantages

5.2 MPC (Model Predictive Control)

Model Predictive Control (MPC) is an advanced control strategy that computes optimal control inputs by solving an optimization problem over a finite prediction horizon at each time step. It uses a mathematical model of the vehicle to predict future states and optimize a cost function subject to constraints.

Core Principle: Receding Horizon

At each time step, MPC:

  1. Predicts the vehicle's future states over a horizon of $N$ steps using the vehicle dynamics model.
  2. Solves an optimization problem to find the control sequence that minimizes a cost function (tracking error, control effort, comfort).
  3. Applies only the first control input from the optimal sequence.
  4. Advances one time step, receives new state measurements, and repeats the process.

This "receding horizon" approach continuously re-optimizes as new information becomes available, providing robustness to model inaccuracies and disturbances.

MPC Optimization Formulation

The general MPC optimization problem can be expressed as:

$$\min_{u_0, \ldots, u_{N-1}} \sum_{k=0}^{N-1} \left[ \| x_k - x_k^{\text{ref}} \|_Q^2 + \| u_k \|_R^2 \right] + \| x_N - x_N^{\text{ref}} \|_P^2$$

subject to:

$$x_{k+1} = f(x_k, u_k) \quad \text{(vehicle dynamics model)}$$ $$x_k \in \mathcal{X} \quad \text{(state constraints: speed limits, lane boundaries)}$$ $$u_k \in \mathcal{U} \quad \text{(input constraints: steering limits, acceleration limits)}$$

where:

Advantages

Disadvantages

5.3 2025-2026 Latest Control Technologies

Recent advances in autonomous vehicle control focus on combining classical and learning-based methods to achieve both safety and adaptability:

MPS (MPC + Stanley Integration)

DDMPC (Data-Driven MPC)

Adaptive MPC + PSO Optimization

Variable Prediction Horizon MPC

DRL + MPC-PID Hybrid Control


6. Major Companies and Players

The autonomous driving industry features a diverse ecosystem of technology companies, automakers, and startups, each pursuing different strategies and levels of autonomy. This section profiles 14 major players as of early 2026.

6.1 Waymo (Alphabet)

Waymo, Alphabet's autonomous driving subsidiary, operates the world's most advanced Level 4 robotaxi service. Its technology stack relies on LiDAR + camera + radar sensor fusion, providing robust redundant perception.

Current Deployment (2025)

2026 Expansion Plan

Gen 6 Hardware

6.2 Tesla

Tesla pursues a vision-only approach consistently, relying exclusively on cameras without LiDAR or radar, leveraging its massive fleet data advantage.

FSD (Full Self-Driving) Supervised

Robotaxi Program

2026 Plans

6.3 Cruise (GM)

Cruise, once General Motors' flagship autonomous driving venture, underwent a dramatic strategic pivot following a serious safety incident.

Key Timeline

6.4 Baidu Apollo Go (China)

Baidu's Apollo Go is China's largest and most advanced robotaxi platform, leading the country's autonomous driving deployment.

Deployment Scale

Economics

International Expansion

6.5 Mobileye (Intel)

Mobileye, an Intel subsidiary, is the dominant supplier of advanced driver-assistance system (ADAS) chips and software, with its technology embedded in vehicles from most major automakers.

Technology and Market Position

Robotaxi Program

Challenges

6.6 NVIDIA

NVIDIA provides the foundational computing platform for autonomous driving, spanning training infrastructure, simulation, and in-vehicle processing.

DRIVE Platform

Alpamayo (CES 2026)

Partnerships and Revenue

6.7 Chinese Startups

Pony.ai

WeRide

AutoX

6.8 Argo AI (Closed)

Argo AI serves as a cautionary tale about the challenges of commercializing Level 4 autonomous driving.

6.9 Zoox (Amazon)

Zoox, acquired by Amazon in 2020, takes a unique approach with a purpose-built autonomous vehicle designed from scratch rather than retrofitting existing cars.

Vehicle Design

Deployment Status

2026 Plans

6.10 Motional (Hyundai / Aptiv)

Motional is a joint venture between Hyundai Motor Group and Aptiv, focused on developing Level 4 robotaxi technology.

6.11 Toyota (Woven by Toyota)

Toyota pursues autonomous driving through its Woven by Toyota subsidiary, combining a software platform strategy with a unique physical testing environment.

Arene Software Platform

Woven City

Strategic Partnerships

Robotaxi Plans

6.12 Honda

Honda has been a pioneer in production-vehicle autonomy, achieving a historic world first with Level 3 deployment.

SENSING Elite (Level 3)

SENSING 360+ (2025)

6.13 Nissan ProPILOT

Nissan's ProPILOT system is the company's advanced driver assistance platform, evolving toward greater autonomy through AI integration.

ProPILOT Assist 2.1

Next-Generation ProPILOT

6.14 Sony Honda Mobility AFEELA

AFEELA is the product of a joint venture between Sony and Honda, combining Sony's sensor and entertainment expertise with Honda's automotive manufacturing capabilities.

AFEELA 1 Sedan

Autonomy Roadmap

Launch Timeline


Chapter Summary

This chapter covered the planning, control, and industry landscape of autonomous driving:

Disclaimer