Suraj Jaiswal

• Zhang, Li; Jaiswal, Suraj; Pan, Yongjun & Mikkola, Aki (2026). Global-Coordinate Formulation With Iterative Refinement in Multi-Physics Simulation of Hydraulically Actuated Mechanisms. IEEE Access. 14, s. 145241–145253. doi: 10.1109/ACCESS.2026.3735012. Fulltekst i vitenarkiv Vis sammendrag

  This study presents a global-coordinate formulation with iterative refinement for the multi-physics simulation of hydraulically actuated mechanisms. To reduce the computational burden in the coupled multibody-hydraulic simulation environment, the proposed strategy uses coordinate partitioning to separate independent and dependent coordinates. Unlike conventional coordinate partitioning implementations, in which independent and dependent coordinates are commonly updated within the same integration procedure, the present strategy advances only the independent coordinates in the Runge–Kutta integrator, whereas the dependent coordinates are reconstructed and refined from the updated independent coordinates through partitioned constraint equations. The strategy was implemented in both a global-coordinate partitioning formulation and a double-step semi-recursive formulation. For independent coordinates, iterative refinement reuses the factorizations of the constrained generalized mass matrix to construct improved acceleration estimates. For the dependent coordinates, the residual correction based on the partitioned constraint Jacobian was used to recover a constraint-consistent configuration before the hydraulic pressure derivatives and actuator forces were evaluated. Numerical simulations of a hydraulically actuated four-bar mechanism show that the proposed refinement strategy reduces the algebraic correction effort and computational time relative to the corresponding non-refined baselines while preserving comparable pressure response, energy balance, and constraint accuracy.

• Zhang, Li; Jaiswal, Suraj; Pan, Yongjun & Mikkola, Aki (2026). Multibody simulation of mechanical systems using the coordinate partitioning method. Acta Mechanica Sinica. ISSN 0567-7718. 42. doi: 10.1007/s10409-026-25497-x. Fulltekst i vitenarkiv Vis sammendrag

  This paper systematically investigates numerical strategies for updating dependent coordinates in multibody dynamics simulations, focusing on resolving the inherent conflict between computational efficiency and numerical accuracy within coordinate partitioning frameworks. Addresses this gap by evaluating three representative methods—Exact coordinate update, Newton increment, and Newton-Raphson—under a unified framework. Benchmark cases include planar two-bar and four-bar mechanisms as well as a spatial slider-crank mechanism. Computational efficiency, constraint violation, energy error, and kinematic accuracy are compared across varying time-step sizes. Results show that the exact update achieves the highest accuracy but at high computational cost, the increment update provides superior speed but deteriorates with larger steps, and the Newton-Raphson update offers a balanced trade-off suitable for general-purpose simulations. Furthermore, we identify dependent coordinate update operations as the dominant computational bottleneck (60%-90% of runtime). These findings provide practical guidelines for selecting update strategies in real-time versus high-accuracy simulations and highlight avenues for performance optimization in complex multibody systems.

• Jaiswal, Suraj & Poursina, Ali M. (2025). Historical Evolution of Heavy Machinery and a General Role of Multibody Dynamics. Machines. 13(8). doi: 10.3390/machines13080741. Fulltekst i vitenarkiv Vis sammendrag

  Heavy machinery has evolved significantly in productivity, efficiency, and safety over the past century and a half, where most technological advances occurred after the 1990s. The field of multibody dynamics has significantly contributed to this development. The objective of this study is to introduce the historical evolution of heavy machinery and to analyze the general role of multibody dynamics in this evolution. The latter part of the objective is the novel contribution of this study. The historical evolution of heavy machinery is presented from the ancient times of 30–20 BC to the modern innovations of 2024. The general role of multibody dynamics in heavy machinery is identified and analyzed in five phases, from using simple kinematic models in the 1970s to real-time simulations and autonomous systems in the 2020s. This study can serve as a benchmark for future work.

• Jaiswal, Suraj; Poursina, Mohammad & Mikkola, Aki (2025). Comparing various semi-recursive multibody methods based on different reference frames in simulating mechanical systems. Multibody system dynamics. ISSN 1384-5640. doi: 10.1007/s11044-025-10117-6. Fulltekst i vitenarkiv Vis sammendrag

  Mechanical systems are extensively utilized in many fields such as the forest, earth-moving, and mining industries. The computer simulation of a mechanical system is often carried out by utilizing a multibody dynamics approach, where various semi-recursive methods can lead to varied computational efficiencies. The objective of this paper is to introduce and systematically compare various semi-recursive multibody methods based on different reference frames in the framework of the index-3 augmented Lagrangian method with projections. The novelty of this paper is the direct formulation and implementation of the method in the center of mass reference frame, whereas the method in the instantaneous reference frame is taken from the literature. Here, simulation models of four-bar, slider-crank, and quick-return mechanical structures are demonstrated as numerical examples. The methods are analyzed depending on the simulation accuracy, violation of constraints, mechanical energy balance, and computational efficiency. The results show that for the presented examples, the center of mass reference frame method is computationally efficient and accurate compared to the method taken from the literature.

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