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Move elasticity force computation to the engine.

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PiperOrigin-RevId: 676028775
Change-Id: I994e3dda8d6470815763c04df0c276e265aa1f54
This commit is contained in:
Alessio Quaglino
2024-09-18 09:53:11 -07:00
committed by Copybara-Service
parent e439b748a4
commit 66a9cacc90
6 changed files with 127 additions and 38 deletions
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plugin/elasticity/solid.cc
+6 -11
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@@ -32,14 +32,10 @@ namespace mujoco::plugin::elasticity {
// factory function
std::optional<Solid> Solid::Create(const mjModel* m, mjData* d, int instance) {
if (CheckAttr("face", m, instance) &&
CheckAttr("edge", m, instance) &&
CheckAttr("poisson", m, instance) &&
CheckAttr("young", m, instance)) {
mjtNum nu = strtod(mj_getPluginConfig(m, instance, "poisson"), nullptr);
mjtNum E = strtod(mj_getPluginConfig(m, instance, "young"), nullptr);
CheckAttr("edge", m, instance)) {
mjtNum damp =
strtod(mj_getPluginConfig(m, instance, "damping"), nullptr);
return Solid(m, d, instance, nu, E, damp);
return Solid(m, d, instance, damp);
} else {
mju_warning("Invalid parameter specification in solid plugin");
return std::nullopt;
@@ -47,8 +43,7 @@ std::optional<Solid> Solid::Create(const mjModel* m, mjData* d, int instance) {
}
// plugin constructor
Solid::Solid(const mjModel* m, mjData* d, int instance, mjtNum nu, mjtNum E,
mjtNum damp)
Solid::Solid(const mjModel* m, mjData* d, int instance, mjtNum damp)
: f0(-1), damping(damp) {
// count plugin bodies
nv = ne = 0;
@@ -109,8 +104,8 @@ void Solid::Compute(const mjModel* m, mjData* d, int instance) {
// Animation" http://multires.caltech.edu/pubs/DiscreteLagrangian.pdf
for (int idx = 0; idx < ne; idx++) {
elongation[idx] = deformed[idx]*deformed[idx] - ref[idx]*ref[idx] +
( deformed[idx]*deformed[idx] - prev[idx]*prev[idx] ) * kD;
elongation[idx] =
(deformed[idx] * deformed[idx] - prev[idx] * prev[idx]) * kD;
}
// compute gradient of elastic energy and insert into passive force
@@ -138,7 +133,7 @@ void Solid::RegisterPlugin() {
plugin.name = "mujoco.elasticity.solid";
plugin.capabilityflags |= mjPLUGIN_PASSIVE;
const char* attributes[] = {"face", "edge", "young", "poisson", "damping", "thickness"};
const char* attributes[] = {"face", "edge", "damping"};
plugin.nattribute = sizeof(attributes) / sizeof(attributes[0]);
plugin.attributes = attributes;
plugin.nstate = +[](const mjModel* m, int instance) { return 0; };