A real-time dynamic simulation platform for multi-DOF rigid body systems based on a novel explicit modelling method

• A real-time dynamics simulation platform is developed for multi-DOF rigid body systems. • Block matrix dynamics formulation enables fast and parallelizable computation. • Real-time simulation is demonstrated on 6, 26, and 48-DOF complex systems. Dynamic simulation is critical for the design and control of complex multi-DOF rigid body systems. Existing general-purpose dynamics software often relies on pre-built toolkits or open source libraries, which provide versatile functions but face challenges such as functional constraints and difficulty in error tracking. This study presents a self-developed, modular simulation platform based on an explicit joint space canonical dynamics formulation. The proposed approach extends the explicit dynamics theory by exploiting its block matrix structure: rotational and prismatic joints are classified, and the joint space mass matrix and bias force vector are assembled explicitly at the block level, enabling parallel computation of only half of the symmetric matrix, thus allowing real-time performance for multi-DOF systems. The entire numerical pipeline from topology initialization to forward and inverse dynamics solving is transparent, lightweight, and implemented in C++, ensuring full controllability and solver traceability. The platform demonstrates real-time simulation in millisecond level for a 6-DOF robotic arm, a 25-DOF Mars rover, and a 48-DOF multi-satellite system on standard CPUs, validating its accuracy, stability, and engineering applicability. This work highlights a way from traditional recursive solvers to an explicit dynamics framework for robotic and aerospace systems.