Fix kinova joint angles

Author: jhavl

roboticstoolbox/examples/test.py

@@ -2,24 +2,141 @@
 import roboticstoolbox as rtb
 import spatialmath as sm
 
-q0 = np.array(
-    [
-        -1.66441371,
-        -1.20998727,
-        1.04248366,
-        -2.10222463,
-        1.05097407,
-        1.41173279,
-        0.0053529,
-    ]
+# q0 = np.array(
+#     [
+#         -1.66441371,
+#         -1.20998727,
+#         1.04248366,
+#         -2.10222463,
+#         1.05097407,
+#         1.41173279,
+#         0.0053529,
+#     ]
+# )
+
+# tol = 1e-6
+
+# panda = rtb.models.Panda().ets()
+
+# Tep = panda.eval([0, -0.3, 0, -2.2, 0, 2.0, np.pi / 4])
+
+# solver = rtb.IK_QP()
+
+# sol = panda.ik_LM(Tep, tol=tol, q0=q0, method="chan")
+
+robot = rtb.models.KinovaGen3()
+
+glink = rtb.Link(
+    rtb.ET.tz(0.12),
+    name="gripper_link",
+    m=0.831,
+    r=[0, 0, 0.0473],
+    parent=robot.links[-1],
 )
 
-tol = 1e-6
+robot.links.append(glink)
+
+
+n = len(robot.links)
+
+print(n)
+
+# allocate intermediate variables
+Xup = sm.SE3.Alloc(n)
+Xtree = sm.SE3.Alloc(n)
+
+# The body velocities, accelerations and forces
+v = sm.SpatialVelocity.Alloc(n)
+a = sm.SpatialAcceleration.Alloc(n)
+f = sm.SpatialForce.Alloc(n)
+
+# The joint inertia
+I = sm.SpatialInertia.Alloc(n)  # noqa: E741
+
+# Joint motion subspace matrix
+s = []
+
+q = robot.qr
+qd = np.zeros(n)
+qdd = np.zeros(n)
+
+Q = np.zeros(n)
+
+# for link in robot.links:
+#     print()
+#     print(link.name)
+#     print(link.isjoint)
+#     print(link.m)
+
+# for link in robot.grippers[0].links:
+#     print()
+#     print(link.name)
+#     print(link.isjoint)
+#     print(link.m)
+
+for i, link in enumerate(robot.links):
+
+    # Allocate the inertia
+    I[i] = sm.SpatialInertia(link.m, link.r, link.I)
+
+    # Compute the link transform
+    Xtree[i] = sm.SE3(link.Ts, check=False)  # type: ignore
+
+    # Append the variable axis of the joint to s
+    if link.v is not None:
+        s.append(link.v.s)
+    else:
+        s.append(np.zeros(6))
+
+a_grav = -sm.SpatialAcceleration([0, 0, 9.81])
+
+# Forward recursion
+for i, link in enumerate(robot.links):
+
+    if link.jindex is None:
+        qi = 0
+        qdi = 0
+        qddi = 0
+    else:
+        qi = q[link.jindex]
+        qdi = qd[link.jindex]
+        qddi = qdd[link.jindex]
+
+    vJ = sm.SpatialVelocity(s[i] * qdi)
+
+    # Transform from parent(j) to j
+    if link.isjoint:
+        Xup[i] = sm.SE3(link.A(qi)).inv()
+    else:
+        Xup[i] = sm.SE3(link.A()).inv()
+
+    if link.parent is None:
+        v[i] = vJ
+        a[i] = Xup[i] * a_grav + sm.SpatialAcceleration(s[i] * qddi)
+    else:
+        jp = link.parent.jindex  # type: ignore
+        v[i] = Xup[i] * v[i - 1] + vJ
+        a[i] = Xup[i] * a[i - 1] + sm.SpatialAcceleration(s[i] * qddi) + v[i] @ vJ
+
+    f[i] = I[i] * a[i] + v[i] @ (I[i] * v[i])
+
+# backward recursion
+for i in reversed(range(n)):
+
+    link = robot.links[i]
+
+    Q[i] = sum(f[i].A * s[i])
 
-panda = rtb.models.Panda().ets()
+    if link.parent is not None:
+        f[i - 1] = f[i - 1] + Xup[i] * f[i]
 
-Tep = panda.eval([0, -0.3, 0, -2.2, 0, 2.0, np.pi / 4])
+print(np.round(Q, 2))
 
-solver = rtb.IK_QP()
 
-sol = panda.ik_LM(Tep, tol=tol, q0=q0, method="chan")
+for link in robot.links:
+    print()
+    print(link.name)
+    print(link.isjoint)
+    print(link.m)
+    print(link.r)
+    print(link.I)

roboticstoolbox/models/URDF/KinovaGen3.py

@@ -47,7 +47,7 @@ def __init__(self):
         # self.qdlim = np.array([
         # 2.1750, 2.1750, 2.1750, 2.1750, 2.6100, 2.6100, 2.6100, 3.0, 3.0])
 
-        self.qr = np.array([np.pi, -0.3, 0, -1.6, 0, -1.0, np.pi / 2])
+        self.qr = np.deg2rad([0.0, 15.0, 180.0, 230.0, 0.0, 55.0, 90.0])
         self.qz = np.zeros(7)
 
         self.addconfiguration("qr", self.qr)
@@ -57,6 +57,7 @@ def __init__(self):
 if __name__ == "__main__":  # pragma nocover
 
     robot = KinovaGen3()
+    robot.q = robot.qr
     print(robot)
 
     from swift import Swift