chenlin/Mujoco_WASM
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Fix bug in muscle length-gain curve. Fixes #1342

Browse Source 
PiperOrigin-RevId: 599165049
Change-Id: Ic5ef77b4349a8a9c343eacfd781195bfebea9aca
This commit is contained in:
Yuval Tassa
2024-01-17 07:19:11 -08:00
committed by Copybara-Service
parent 67a00a3a51
commit a14a584f1d
5 changed files with 47 additions and 38 deletions
Download Patch File Download Diff File Expand all files Collapse all files
doc/changelog.rst
+2
View File
@@ -21,6 +21,8 @@ Bug fixes
^^^^^^^^^
6. Fixed a bug that prevented the use of pins with plugins if flexes are not in the worldbody. Fixes
:github:issue:`1270`.
7. Fixed a bug in the :ref:`muscle model<CMuscle>` that led to non-zero values outside the lower
bound of the length range. Fixes :github:issue:`1342`.
Version 3.1.1 (December 18, 2023)
src/engine/engine_derivative.c
+1 -19
View File
@@ -790,11 +790,6 @@ static mjtNum mjd_muscleGain_vel(mjtNum len, mjtNum vel, const mjtNum lengthrang
force = scale / mju_max(mjMINVAL, acc0);
}
// mid-ranges
mjtNum a = 0.5*(lmin+1);
mjtNum b = 0.5*(1+lmax);
mjtNum x;
// optimum length
mjtNum L0 = (lengthrange[1]-lengthrange[0]) / mju_max(mjMINVAL, range[1]-range[0]);
@@ -803,20 +798,7 @@ static mjtNum mjd_muscleGain_vel(mjtNum len, mjtNum vel, const mjtNum lengthrang
mjtNum V = vel / mju_max(mjMINVAL, L0*vmax);
// length curve
mjtNum FL = 0;
if (L >= lmin && L <= a) {
x = (L-lmin) / mju_max(mjMINVAL, a-lmin);
FL = 0.5*x*x;
} else if (L <= 1) {
x = (1-L) / mju_max(mjMINVAL, 1-a);
FL = 1 - 0.5*x*x;
} else if (L <= b) {
x = (L-1) / mju_max(mjMINVAL, b-1);
FL = 1 - 0.5*x*x;
} else if (L <= lmax) {
x = (lmax-L) / mju_max(mjMINVAL, lmax-b);
FL = 0.5*x*x;
}
mjtNum FL = mju_muscleGainLength(L, lmin, lmax);
// velocity curve
mjtNum dFV;
src/engine/engine_util_misc.c
+28 -19
View File
@@ -455,6 +455,33 @@ void mju_geomSemiAxes(const mjModel* m, int geom_id, mjtNum semiaxes[3]) {
//------------------------------ actuator models ---------------------------------------------------
// normalized muscle length-gain curve
mjtNum mju_muscleGainLength(mjtNum length, mjtNum lmin, mjtNum lmax) {
if (lmin <= length && length <= lmax) {
// mid-ranges (maximum is at 1.0)
mjtNum a = 0.5*(lmin+1);
mjtNum b = 0.5*(1+lmax);
if (length <= a) {
mjtNum x = (length-lmin) / mjMAX(mjMINVAL, a-lmin);
return 0.5*x*x;
} else if (length <= 1) {
mjtNum x = (1-length) / mjMAX(mjMINVAL, 1-a);
return 1 - 0.5*x*x;
} else if (length <= b) {
mjtNum x = (length-1) / mjMAX(mjMINVAL, b-1);
return 1 - 0.5*x*x;
} else {
mjtNum x = (lmax-length) / mjMAX(mjMINVAL, lmax-b);
return 0.5*x*x;
}
}
return 0.0;
}
// muscle active force, prm = (range[2], force, scale, lmin, lmax, vmax, fpmax, fvmax)
mjtNum mju_muscleGain(mjtNum len, mjtNum vel, const mjtNum lengthrange[2],
mjtNum acc0, const mjtNum prm[9]) {
@@ -472,11 +499,6 @@ mjtNum mju_muscleGain(mjtNum len, mjtNum vel, const mjtNum lengthrange[2],
force = scale / mjMAX(mjMINVAL, acc0);
}
// mid-ranges
mjtNum a = 0.5*(lmin+1);
mjtNum b = 0.5*(1+lmax);
mjtNum x;
// optimum length
mjtNum L0 = (lengthrange[1]-lengthrange[0]) / mjMAX(mjMINVAL, range[1]-range[0]);
@@ -485,20 +507,7 @@ mjtNum mju_muscleGain(mjtNum len, mjtNum vel, const mjtNum lengthrange[2],
mjtNum V = vel / mjMAX(mjMINVAL, L0*vmax);
// length curve
mjtNum FL = 0;
if (L >= lmin && L <= a) {
x = (L-lmin) / mjMAX(mjMINVAL, a-lmin);
FL = 0.5*x*x;
} else if (L <= 1) {
x = (1-L) / mjMAX(mjMINVAL, 1-a);
FL = 1 - 0.5*x*x;
} else if (L <= b) {
x = (L-1) / mjMAX(mjMINVAL, b-1);
FL = 1 - 0.5*x*x;
} else if (L <= lmax) {
x = (lmax-L) / mjMAX(mjMINVAL, lmax-b);
FL = 0.5*x*x;
}
mjtNum FL = mju_muscleGainLength(L, lmin, lmax);
// velocity curve
mjtNum FV;
src/engine/engine_util_misc.h
+3
View File
@@ -33,6 +33,9 @@ mjtNum mju_wrap(mjtNum* wpnt, const mjtNum* x0, const mjtNum* x1,
const mjtNum* xpos, const mjtNum* xmat, const mjtNum* size,
int type, const mjtNum* side);
// normalized muscle length-gain curve
MJAPI mjtNum mju_muscleGainLength(mjtNum length, mjtNum lmin, mjtNum lmax);
// muscle active force, prm = (range[2], force, scale, lmin, lmax, vmax, fpmax, fvmax)
MJAPI mjtNum mju_muscleGain(mjtNum len, mjtNum vel, const mjtNum lengthrange[2],
mjtNum acc0, const mjtNum prm[9]);
test/engine/engine_util_misc_test.cc
+13
View File
@@ -135,6 +135,19 @@ TEST_F(MujocoTest, SmoothMuscleDynamics) {
}
}
TEST_F(MujocoTest, MuscleGainLength) {
mjtNum lmin = 0.5;
mjtNum lmax = 1.5;
EXPECT_EQ(mju_muscleGainLength(0.0, lmin, lmax), 0);
EXPECT_EQ(mju_muscleGainLength(0.5, lmin, lmax), 0);
EXPECT_EQ(mju_muscleGainLength(0.75, lmin, lmax), 0.5);
EXPECT_EQ(mju_muscleGainLength(1.0, lmin, lmax), 1);
EXPECT_EQ(mju_muscleGainLength(1.25, lmin, lmax), 0.5);
EXPECT_EQ(mju_muscleGainLength(1.5, lmin, lmax), 0);
EXPECT_EQ(mju_muscleGainLength(2.0, lmin, lmax), 0);
}
TEST_F(MujocoTest, mju_makefullname) {
char buffer[1000];
constexpr char path[] = "engine/testdata/";