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[Admittance] applies control frame transform to mass matrix #1139

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[Admittance] applies control frame transform to mass matrix #1139

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c544c64
fix: applies control frame transform to mass matrix in admittance con…
MarcoMagriDev May 22, 2024
6f16aa9
Merge branch 'master' into fix-admittance-controller-mass
MarcoMagriDev Jul 5, 2024
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14 changes: 12 additions & 2 deletions admittance_controller/include/admittance_controller/admittance_rule_impl.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -248,6 +248,17 @@ bool AdmittanceRule::calculate_admittance_rule(AdmittanceState & admittance_stat
D.block<3, 3>(0, 0) = D_pos;
D.block<3, 3>(3, 3) = D_rot;

// The same for mass
Eigen::Matrix<double, 6, 6> M_inv = Eigen::Matrix<double, 6, 6>::Zero();
Eigen::Matrix<double, 3, 3> M_inv_pos = Eigen::Matrix<double, 3, 3>::Zero();
Eigen::Matrix<double, 3, 3> M_inv_rot = Eigen::Matrix<double, 3, 3>::Zero();
M_inv_pos.diagonal() = admittance_state.mass_inv.block<3, 1>(0, 0);
M_inv_rot.diagonal() = admittance_state.mass_inv.block<3, 1>(3, 0);
M_inv_pos = rot_base_control * M_inv_pos * rot_base_control.transpose();
M_inv_rot = rot_base_control * M_inv_rot * rot_base_control.transpose();
M_inv.block<3, 3>(0, 0) = M_inv_pos;
M_inv.block<3, 3>(3, 3) = M_inv_rot;

// calculate admittance relative offset in base frame
Eigen::Isometry3d desired_trans_base_ft;
kinematics_->calculate_link_transform(
Expand Down Expand Up @@ -276,8 +287,7 @@ bool AdmittanceRule::calculate_admittance_rule(AdmittanceState & admittance_stat
F_base.block<3, 1>(3, 0) = rot_base_control * F_control.block<3, 1>(3, 0);

// Compute admittance control law in the base frame: F = M*x_ddot + D*x_dot + K*x
Eigen::Matrix<double, 6, 1> X_ddot =
admittance_state.mass_inv.cwiseProduct(F_base - D * X_dot - K * X);
Eigen::Matrix<double, 6, 1> X_ddot = M_inv * (F_base - D * X_dot - K * X);
bool success = kinematics_->convert_cartesian_deltas_to_joint_deltas(
admittance_state.current_joint_pos, X_ddot, admittance_state.ft_sensor_frame,
admittance_state.joint_acc);
Expand Down