Learning Dissipative Dynamics with Dissipativity-by-Construction Discrete-Time Neural Networks
Organizations: Department of Mechanical Engineering, Sungkyunkwan University, Suwon 16419, South Korea
Abstract
Dissipativity is a fundamental system-theoretic property closely related to stability, passivity, and input--output stability, and is particularly important in robotics, where learned dynamics models are often embedded within feedback control loops. However, most existing approaches for learning dissipative dynamics are based on continuous-time formulations, which require ODE solvers during training or inference and can therefore be computationally expensive. Moreover, because practical implementations are inherently discrete-time, direct discretization of a continuous-time passive system does not necessarily preserve passivity, motivating the need for explicit discrete-time guarantees. This study proposes a method for learning incrementally dissipative dynamics from input--output time-series data using a deep multilayer perceptron formulated directly in discrete time. Through a constrained parameterization and a dedicated training procedure, the proposed model guarantees incremental dissipativity by construction rather than through regularization. Lyapunov-based analysis establishes the corresponding dissipativity and stability guarantees, while simulations on robotic dynamical systems demonstrate competitive prediction accuracy, computational efficiency, and consistent preservation of incremental dissipativity compared with baseline methods.
Figures & tables
| System | Noise | MLP | DMLP | |
| MSD | 100 | Yes | ||
| No | ||||
| 200 | Yes | |||
| No | ||||
| 2-DOF | 100 | Yes | ||
| No |
| Model | Performance | MLP | DMLP | Dissipative Neural ODE |
| MSD (10000 epochs) | Mean error | |||
| Computation time | s | s | h | |
| 2-DOF manipulator (5000 epochs) | Mean error | |||
| Computation time | s | s | h | |
| 3-DOF manipulator (5000 epochs) | Mean error | |||
| Computation time | s | s | hour |
Appendix figures & tables3 assets
Supplementary material from the paper’s appendix.
Appendix
| Ablation cases | MSD (10000 epochs) | 2-DOF manipulator (5000 epochs) | 3-DOF manipulator (5000 epochs) | ||||
| Mean error | Training time | Mean error | Training time | Mean error | Training time | ||
| Dissipativity constraints | No (MLP) | s | s | s | |||
| Yes (DMLP) | s | s | s | ||||
| Training algorithm (DMLP) | Improved | s | s | s | |||
| Original | s | s | s | ||||
| Number of layers (DMLP) | 1 | s | s | s | |||
| Hyperparameter | MSD | 2-DOF | 3-DOF |
| Input size | 1 | 2 | 3 |
| Hidden size | 32 | 32 | 32 |
| Output size | 2 | 4 | 6 |
| Number of layers | 2 | 2 | 2 |
| Activation function | tanh | tanh | tanh |
Robot Dynamics Learning
Robot dynamics learning builds models that predict how robots and objects move under actions, enabling control, planning, and adaptation.
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