inverse-dynamics-derivatives.py

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import numpy as np
import pinocchio as pin
 
 
 
# Create model and data
 
model = pin.buildSampleModelHumanoidRandom()
data = model.createData()
 
# Set bounds (by default they are undefinded for a the Simple Humanoid model)
 
model.lowerPositionLimit = -np.ones((model.nq, 1))
model.upperPositionLimit = np.ones((model.nq, 1))
 
q = pin.randomConfiguration(model)  # joint configuration
v = np.random.rand(model.nv, 1)  # joint velocity
a = np.random.rand(model.nv, 1)  # joint acceleration
 
# Evaluate the derivatives
 
pin.computeRNEADerivatives(model, data, q, v, a)
 
# Retrieve the derivatives in data
 
dtau_dq = data.dtau_dq  # Derivatives of the ID w.r.t. the joint config vector
dtau_dv = data.dtau_dv  # Derivatives of the ID w.r.t. the joint velocity vector
dtau_da = data.M  # Derivatives of the ID w.r.t. the joint acceleration vector