The reference node positions and the positions used for computing stiffness eigenvectors were previously stored in world frame. However, the runtime expects these quantities in the unrotated local frame. This caused non-zero constraint residuals and simulation instability when the grid was rotated — either by the parent body's initial orientation, or by the flexcomp's own frame attributes.
Rather than tracking each rotation source individually, this change extracts the total grid rotation directly from the cell geometry. All node positions are then un-rotated before computing the stiffness matrix.
PiperOrigin-RevId: 903232388
Change-Id: If877af89025ce1e61a76b38c29403d593d892749
This provides a reduction from 26 to 18 constraints for trilinear and from 162 to 75 for quadratic. The assembly of the constraints becomes trivial. In total the speedup for a trilinear 3x3x3 grid is about 3x.
PiperOrigin-RevId: 902502398
Change-Id: I764772c7adef78da5a644f64701f842d36e4b543
The flex interpolation stiffness matrix within the implicit/implicitfast solvers is now built and factorized in a banded format instead of a dense one. This involves:
- Calculating the bandwidth based on the sparsity of the mass/damping matrix and the connectivity within flex cells.
- Allocating and populating a banded matrix `H`.
- Using `mju_cholFactorBand` and `mju_cholSolveBand` for factorization and solving.
This change improves performance for flexes with many DOFs but local coupling.
PiperOrigin-RevId: 901297952
Change-Id: I3efe06353d1903ea65ab30dc49685cede228bb68
This change introduces a `flex_cellcount` field to `mjModel` to specify the number of cells in each dimension for interpolated flexes. The stiffness computation, passive force calculation, and Jacobian derivatives are updated to operate on a per-cell basis, significantly improving performance by localizing computations to the nodes within each cell.
PiperOrigin-RevId: 901216393
Change-Id: Ic23132e609de11e71bb7fef8d1f139daad2ec264
- Remove `lugre:viscous`, should now be added directly to actuator `damping`. Trying to do this for the user was incompatible with default inheritance (compounding instead of overriding).
- Move voltage limiting from the `saturation` to the `controller` attribute.
- Fix indexing issues in default inheritance.
PiperOrigin-RevId: 897087642
Change-Id: I5388c2633e15c7e223992e7eb5d6a28db75a6438
The frustum_top and frustum_bottom assignments in mjv_updateCamera used
the wrong elements of the zver array, causing the principal point cy
offset to be applied with an inverted sign. This shifted the rendered
image vertically by 2*cy pixels.
The flex-SDF algorithm uses the same logic as mesh-SDF. Previous to this change, the flex was instead colliding with the convex hull of the mesh generated automatically with marching cubes from the SDF.
PiperOrigin-RevId: 876420302
Change-Id: I3bf6552b6b8e108ba4c4209bbcf10fe5f2b2fd90
MujocoTest now loads plugins from MUJOCO_PLUGIN_DIR if set.
PluginTest is removed; all tests use MujocoTest directly.
testspeed binary loads plugins from MUJOCO_PLUGIN_DIR.
This is in preparation for moving common asset format parsing (obj, msh, stl, etc.) where we will always want to load those plugins.
PiperOrigin-RevId: 874194428
Change-Id: Id90805a9ba5de4627911b56d8b9c4ab4e1b29310
The reduced dense factorization for flex interpolation now considers all DOFs in the kinematic chain of the body containing the flex, using mj_bodyChain, instead of only the DOFs directly associated with that body. This is necessary for correctly handling pinned flexes when their parent body is part of a larger kinematic structure.
PiperOrigin-RevId: 872854468
Change-Id: Idbe9fb459084dde9e8eb1076c70dbb685c1b0bdb
The derivatives of actuator velocity with respect to generalized velocities were incorrectly computed when the actuator force was limited by `forcerange`. This CL adds a check to zero out these derivatives when the actuator force is at its upper or lower limit, as the force is no longer a function of velocity in this clamped state.
PiperOrigin-RevId: 868818281
Change-Id: I89742a3f04989dd11f9cfada107200015b1472a7
Replace dynamically-sized edge list with a dense ntree×ntree adjacency matrix for deduplication and a flat CSR representation.
PiperOrigin-RevId: 868728432
Change-Id: Iebe97a0870740e5465549b967bbde0c81e658269
The derivative calculation for actuator velocity in implicit integrators now correctly accounts for the `actearly` flag, using the next activation value when `actearly` is true.
PiperOrigin-RevId: 868598722
Change-Id: Ia180afb15b31a718170aeaf9d4ac514bb9e6073b
The implicit integrator was not correctly accounting for the off-diagonal coupling terms between flex and non-flex (parent) degrees of freedom in the mass matrix. This change extracts these coupling terms during the factorization step and applies a correction to the flex forces before solving for the flex accelerations, ensuring that the parent accelerations influence the flex dynamics. A new test verifies that the implicit integrator now matches Euler for small timesteps in a model with flex-parent coupling.
PiperOrigin-RevId: 868098126
Change-Id: Ia8cccd7dd428cd0c0898e1663a7e41017a2311b2
The functions and associated tests related to managing time-stamped data buffers have been renamed from `mju_delay*` to `mju_history*` to better reflect their general purpose beyond just handling delays.
PiperOrigin-RevId: 866978339
Change-Id: I8655e91bce783287ad2adc412d13a1c39aa2c322
Alessio Quaglino