#include <sr_friction_compensation.hpp>

Public Member Functions
double	friction_compensation (double position, double velocity, int force_demand, int deadband)
	SrFrictionCompensator (std::string joint_name)
	~SrFrictionCompensator ()
Private Member Functions
std::vector < joint_calibration::Point >	generate_flat_map ()
std::pair< std::vector < joint_calibration::Point > , std::vector < joint_calibration::Point > >	read_friction_map ()
std::vector < joint_calibration::Point >	read_one_way_map (XmlRpc::XmlRpcValue raw_map)
Private Attributes
boost::shared_ptr < shadow_robot::JointCalibration >	friction_interpoler_backward
	An interpolator for the backward friction map: used to compute the offset from the map, given the current position.
boost::shared_ptr < shadow_robot::JointCalibration >	friction_interpoler_forward
	An interpolator for the forward friction map: used to compute the offset from the map, given the current position.
std::string	joint_name_
	the joint name
ros::NodeHandle	node_
	node handle for reading the map from the parameters server.
Static Private Attributes
static const double	velocity_for_static_friction = 0.01
	the threshold under which we use the static friction map

Detailed Description

Definition at line 52 of file sr_friction_compensation.hpp.

Constructor & Destructor Documentation

sr_friction_compensation::SrFrictionCompensator::SrFrictionCompensator ( std::string joint_name )

Definition at line 37 of file sr_friction_compensation.cpp.

sr_friction_compensation::SrFrictionCompensator::~SrFrictionCompensator ( )

Definition at line 46 of file sr_friction_compensation.cpp.

Member Function Documentation

double sr_friction_compensation::SrFrictionCompensator::friction_compensation	(	double	position,
		double	velocity,
		int	force_demand,
		int	deadband
	)

Computes the value of the offset to add to the force demand to compensate for the friction. This offset is computed based on the current joint position and on the force demand sign as well, using a friction map.

The friction map is generated by moving the joint very slowly, from one end to the other, while recording the force necessary to move it. Two different map position->force are then created by interpolating those values, one for each direction.

Parameters:

position	the current joint position.
velocity	the current joint velocity.
force_demand	the force demand is used to know in which direction we want to move: if > 0 -> forward if < 0 -> backward
deadband	the deadband on the force_demand (in the deadband region, we're returning an offset of 0.0 for stability reasons).

Returns:: the force necessary to have the joint ready to move.

Definition at line 49 of file sr_friction_compensation.cpp.

std::vector< joint_calibration::Point > sr_friction_compensation::SrFrictionCompensator::generate_flat_map ( ) [private]

Generates a flat map for the joints missing one of their friction map.

Returns:: A flat map (always 0.0)

Definition at line 189 of file sr_friction_compensation.cpp.

std::pair< std::vector< joint_calibration::Point >, std::vector< joint_calibration::Point > > sr_friction_compensation::SrFrictionCompensator::read_friction_map ( ) [private]

Read the 2 friction maps from the parameter servers for each joint. Generate a flat map (no offset) if the map doesn't exist.

Returns:: a pair of map: the first is the forward map, the second is the backward map.

Definition at line 88 of file sr_friction_compensation.cpp.

std::vector< joint_calibration::Point > sr_friction_compensation::SrFrictionCompensator::read_one_way_map ( XmlRpc::XmlRpcValue raw_map ) [private]