Class MinimumEffort
Defined in File MinimumEffort.h
Inheritance Relationships
Base Type
public OpenSoT::Task< Eigen::MatrixXd, Eigen::VectorXd >(Template Class Task)
Class Documentation
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class MinimumEffort : public OpenSoT::Task<Eigen::MatrixXd, Eigen::VectorXd>
The MinimumEffort class implements a task that tries to bring the robot in a minimum-effort posture.
Notice that the weight of the robot is not taken into account when computing effort on the legs (that is, the forces on the floating base are not projected on the contact points jacobians). Also, the minimum effort task is using a simple gradient worker, ComputeGTauGradient, which does not satisfy contact points constraints while performing the configuration vector needed to numerically compute the gradient. In particular, the gravity vector is computed considering a support foot always in contact with the ground. This means in general the minimum effort task should be used together with a cartesian task on the swing foot, imeplemented through the OpenSoT::tasks::velocity::Cartesian class. You can take a look at an implementation example in example_minimum_effort.cpp
Public Types
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typedef std::shared_ptr<MinimumEffort> Ptr
Public Functions
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MinimumEffort(const XBot::ModelInterface &robot_model, const double step = 1E-3)
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~MinimumEffort()
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double computeEffort()
computeEffort
- Returns
the effort at the actual configuration q (ast from latest update(q))
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inline void setW(const Eigen::MatrixXd &W)
setW set a CONSTANT Weight matrix for the manipulability index
- Parameters
W – weight matrix
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inline const Eigen::MatrixXd &getW()
getW get a Weight matrix for the manipulability index
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inline virtual void setLambda(double lambda)
Protected Functions
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virtual void _update()
_update updates the minimum effort gradient.
@detail It also updates the state on the internal robot model so that successive calls to the computeEffort() function will take into account the updated posture of the robot.
- Parameters
x – the actual posture of the robot
Protected Attributes
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const XBot::ModelInterface &_model
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Eigen::VectorXd _q
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ComputeGTauGradient _gTauGradientWorker
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double _step
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Eigen::VectorXd _gradient
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Eigen::VectorXd _deltas
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class ComputeGTauGradient : public CostFunction
The ComputeGTauGradient class implements a worker class to computes the effort for a certain configuration.
It will take into account the robot as standing on a flat floor, and while computing the gradient, we will assume a foot is on the ground. Notice that the way we compute the gradient does not satisfy the constraints of both flat foot on the ground. So in general this simple implementation of the gradient worker needs to be used in a minimum effort task together with a constraint (or a higher priority task) for the swing foot.
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typedef std::shared_ptr<MinimumEffort> Ptr