BipedalLocomotion::Planners::SwingFootPlanner class
#include <BipedalLocomotion/Planners/SwingFootPlanner.h>

SwingFootPlanner implement a minimum jerk trajectory planner for the swing foot.

The planner is designed in SE(3) and we assume that initial 6d-acceleration and 6d-velocity of the foot is always equal to zero at take off. The trajectory of the foot will belong to the Geodesic.

Base classes

template<class Output> class BipedalLocomotion::System::Source<SwingFootPlannerState>: Source is a template specialization of Advanceable and represents a block that does not contains input.

Public functions

auto initialize(std::weak_ptr<const ParametersHandler::IParametersHandler> handler) -> bool final: Initialize the planner.
auto setContactList(const Contacts::ContactList& contactList) -> bool: Set the contact list.
void setTime(const std::chrono::nanoseconds& time): Reset the time.
auto getOutput() const -> const SwingFootPlannerState& final: Get the object.
auto isOutputValid() const -> bool final: Determines the validity of the object retrieved with get()
auto advance() -> bool final: Advance the internal state.

Function documentation

bool BipedalLocomotion::Planners::SwingFootPlanner::initialize(std::weak_ptr<const ParametersHandler::IParametersHandler> handler) final

Initialize the planner.

Parameters
handler	pointer to the parameter handler.
Returns	True in case of success/false otherwise.

Note

the following parameters are required by the class

Parameter Name	Type	Description	Mandatory
`sampling_time`	`double`	Sampling time of the planner in seconds	Yes
`step_height`	`double`	Height of the swing foot. It is not the maximum height of the foot. If apex time is 0.5 `step_height` is the maximum	Yes
`foot_apex_time`	`double`	Number between 0 and 1 representing the foot apex instant. If 0 the apex happens at take off if 1 at touch down	Yes
`foot_landing_velocity`	`double`	Landing vertical velocity (default value 0.0)	No
`foot_landing_acceleration`	`double`	Landing vertical acceleration (default value 0.0)	No
`foot_take_off_velocity`	`double`	Take-off vertical velocity (default value 0.0)	No
`foot_take_off_acceleration`	`double`	Take-off vertical acceleration (default value 0.0)	No
`interpolation_method`	`string`	Define the interpolation method for the trajectory of the position. Accepted parameters: `min_acceleration`, `min_jerk` (default value `min_acceleration`)	No
`position_tolerance`	`double`	Position tolerance in meters considered in SwingFootPlanner::setContactList. (default value 1e-6)	No
`orientation_tolerance`	`double`	Orientation tolerance in radians considered in SwingFootPlanner::setContactList. (default value 1e-6)	No

bool BipedalLocomotion::Planners::SwingFootPlanner::setContactList(const Contacts::ContactList& contactList)

Set the contact list.

Parameters
contactList	contains the list for a given contact.
Returns	true in case of success, false otherwise.

Note

The contact list can be updated at run-time, i.e., when the planner is running. However the new contact list must satisfy a set of hypothesis. If the contact list stored in the class is empty, then it is the first time the contact list is added to the planner. In this case we accept all kinds of ContactList If the contact list is not empty, we check if it is possible to update the list. Given some limitations of the framework (mainly due to the SO3 trajectory generation) for the time being, we support only the two following cases:

Given the current time instant, both the stored and the new contact lists must have an active contact at the same pose. In details the check is done by comparing the position and orientation of the contact. The position and orientation are considered equal if the following two conditions are satisfied:
1. the distance between the two positions is less than position_tolerance
2. the distance between the two orientations is less than orientation_tolerance
If the contact is not active (swing phase) the next contact must satisfy the following two hypothesis
1. the final orientation may change still the error (in the tangent space) between the new orientation and the current one should be parallel to the current velocity and acceleration vectors. This is required to keep the SO3Planner problem still treatable online. This check is not done here since the SO3Planner will complain in case of issues.
2. the impact time of the next contact must be the same as the one of the next contact in the contact list stored in the class.

void BipedalLocomotion::Planners::SwingFootPlanner::setTime(const std::chrono::nanoseconds& time)

Reset the time.

Parameters
time	internal time of the system.

const SwingFootPlannerState& BipedalLocomotion::Planners::SwingFootPlanner::getOutput() const final

Get the object.

Returns	a const reference of the requested object.

bool BipedalLocomotion::Planners::SwingFootPlanner::isOutputValid() const final

Determines the validity of the object retrieved with get()

Returns	True if the object is valid, false otherwise.

bool BipedalLocomotion::Planners::SwingFootPlanner::advance() final

Advance the internal state.

Returns	True if the advance is successfull.

This may change the value retrievable from get().

BipedalLocomotion::Planners::SwingFootPlanner class #include <BipedalLocomotion/Planners/SwingFootPlanner.h>