How can I build a plugin that simulate the magnetic force and torque in IssacSim

[zefew6]

In contrast to the extensively studied rigid-body dynamics in robotics, magnetic dynamics remains a less explored yet highly promising field. Its primary applications lie in the medical domain, such as in capsule endoscopy. However, practical progress is challenged by the complex, highly nonlinear nature of magnetic forces and torques, combined with the significant non-rigidity of the human gastrointestinal tract. These factors render existing model-based control and localization methods inadequate for real-world application.

Reinforcement learning (RL) presents a compelling alternative, with its ability to learn optimal policies through environmental interaction and enhance real-time control performance. Yet, the development of RL-based solutions is severely hampered by the absence of simulation plugins capable of modeling magnetic fields, forces, torques, and non-rigid intestinal environments. This limitation currently restricts researchers from actively exploring this promising direction.

Therefore, I would like to consult my colleagues in the robotics community: What feasible pathways exist to incorporate these capabilities? Specifically, how might one implement simulations for magnetic fields, forces, and torques within IsaacSim?

[PeterL-NV]

This is an interesting topic. Implementing simulations for magnetic fields, forces, and torques within Isaac Sim relies on both physics extensibility and integration with custom force models. Isaac Sim uses NVIDIA's PhysX engine, which does not natively simulate magnetic fields but does support extensible force application frameworks. You can add magnetic effects via custom scripts and extensions.

Magnetic Field Implementation

• Define magnetic field vectors and update functions using Python, typically in the simulation loop.
• Use Isaac Sim's APIs, such as apply_force() and apply_torque() on rigid bodies, to simulate magnetic influences.
• For field visualization, custom rendering or Omniverse USD data can be used.

Calculating Magnetic Forces and Torques

• Implement custom equations, e.g., Lorentz force $F = q(v \times B)$ for moving charges, or torque for dipoles $\tau = m \times B$.
• For ferromagnetic bodies, estimate location, velocity, and apply resulting force at each timestep.
• Script this using Isaac Sim's Python API and callbacks in your simulation loop.

This pattern works for rigid bodies; for articulated models, forces can be applied to individual links using their unique handles.

Integration in Isaac Sim

• Use callbacks, extension modules, or Omniverse Kit scripting to inject custom force and torque logic each simulation tick.
• Data can be processed with numpy for vector math and piped back to the simulation actors.
• For accurate, real-time effects, tune simulation step size, actor mass, and physical properties in the asset's USD definition.