Simulating Automated Guided Vehicles in Unity: A Case Study on PID Controller Tuning

Abstract

The use of simulated environments for the development and validation of Automated Guided Vehicles (AGVs) has proven to be an effective approach for reducing costs and accelerating the testing process. Simulated environments offer a safe and controlled means for performance analysis and controller parameter adjustment. However, most simulators employed for AGVs and mobile robots rely on kinematic models, which limits the fidelity of the tests. This work introduces a physics-driven Unity framework that leverages the NVIDIA PhysX engine to model AGV dynamics—including payload variation, wheel–ground interactions, and suspension effects—addressing a critical gap in surveyed studies. A factory-floor virtual environment was developed, and a holonomic AGV was implemented with RigidBody and WheelCollider components. PID controllers were tuned via Exhaustive Search and Ziegler–Nichols methods across loads from 0 kg to 100 kg. Exhaustive Search achieved a mean lateral error of just 0.0069 cm and a standard deviation of 1.33 cm at 50 kg—58% lower variability than Ziegler–Nichols. Meanwhile, controller tuning using Ziegler–Nichols required only up to 40 min per load but exhibited up to 84% inter-operator gain variability. Performance was validated on infinity-shaped track, demonstrating Unity’s utility for quantitative performance benchmarking. As contributions, this study (i) presents a novel dynamic AGV simulation framework, (ii) proposes a dual validation workflow combining on-site tuning and systematic optimization, and (iii) integrates an embedded evaluation suite for reproducible control- strategy comparisons.