Add the possibility to compensate an external disturbance torques

[mathieu-celerier]

Add a copy of each constructors of MotionConstrCommon, MotionConstr and MotionSpringConstr that includes an additional reference to an Eigen::VectorXd that contains an estimation or the exact value of the external disturbance torques to be compensated for. MotionConstrCommon set a bool depending on which constructor is called to know if external torques should be accounted for.

• This is required to know if the reference is properly initialized. This value is later used in the computeMatrix and computeTorque function of MotionConstrCommon if external torques needs to be compensated.

[Alhuuin]

At first glance, I’m wondering whether overloading the constructors is necessary, since the changes are minimal. Wouldn't an additional argument with a default value (possibly using std::optional) be sufficient?

[ThomasDuvinage]

Hello,

Please find below a review of the PR.
The main concern of this review is the usage of reference for extTorque_. A suggestion regarding this point has been made in one comment.

I agree with @Alhuuin comment on using std::optional, it would make the code simpler.

[mathieu-celerier]

a150ade removes the reference on the external torques makes it optional and add a function in MotionConstrCommon to set its value.
For now, there is no automatic reset of the optional at each update or a mechanism similar, I am not sure that it is necessary but it could be changed.