Actuation interface for the Bullet simulator. More...

#include <BulletInterface.h>

Classes
struct	Parameters
	Interface parameters. More...

Public Member Functions
	BulletInterface (const Parameters &params)
	Initialize interface. More...

	~BulletInterface ()
	Disconnect interface.

void	reset (const Dictionary &config) override
	Reset interface. More...

void	observe (Dictionary &observation) const override
	Write actuation-interface observations to dictionary. More...

void	process_action (const Dictionary &action) override
	Process a new action dictionary. More...

void	process_forces (const Dictionary &external_forces)
	Process a dictionary of additional external forces. More...

void	cycle (std::function< void(const moteus::Output &)> callback) final
	Spin a new communication cycle. More...

Eigen::Matrix4d	get_transform_base_to_world () const noexcept
	Get the groundtruth floating base transform.

Eigen::Matrix4d	get_transform_body_to_world (int body_id) const noexcept
	Get a groundtruth body transform. More...

Eigen::Vector3d	get_linear_velocity_base_to_world_in_world () const noexcept
	Get the groundtruth floating base linear velocity. More...

Eigen::Vector3d	get_angular_velocity_base_in_base () const noexcept
	Get the groundtruth floating base angular velocity. More...

Eigen::VectorXd	get_joint_angles () noexcept
	Get the groundtruth vector of joint angles. More...

void	reset_contact_data ()
	Reset contact data.

void	reset_joint_angles (const Eigen::VectorXd &joint_configuration)
	Reset joint angles. More...

void	reset_joint_properties ()
	Reset joint properties to defaults.

void	reset_base_state (const Eigen::Vector3d &position_base_in_world, const Eigen::Quaterniond &orientation_base_in_world, const Eigen::Vector3d &linear_velocity_base_to_world_in_world, const Eigen::Vector3d &angular_velocity_base_in_base)
	Reset the pose and velocity of the floating base in the world frame. More...

const std::map< std::string, bullet::JointProperties > &	joint_properties ()
	Joint properties (getter used for testing)

const std::map< std::string, moteus::ServoReply > &	servo_reply ()
	Internal map of servo replies (getter used for testing)

double	compute_joint_torque (const std::string &joint_name, const double feedforward_torque, const double target_position, const double target_velocity, const double kp_scale, const double kd_scale, const double maximum_torque)
	Reproduce the moteus position controller in Bullet. More...

double	compute_robot_mass ()
	Compute total robot mass in kg.

Eigen::Vector3d	compute_position_com_in_world ()
	Compute the position of the center of mass in the world frame.

Eigen::Vector3d	get_position_link_in_world (const std::string &link_name)
	Compute the position of a link frame in the world frame. More...

void	save_nominal_masses ()
	Get nominal masses of the robot links.

void	randomize_masses ()
	Randomize masses of the robot links.

Public Member Functions inherited from upkie::cpp::actuation::Interface
	Interface ()
	Initialize actuation interface for a given servo layout.

virtual	~Interface ()=default
	Virtual destructor so that derived destructors are called properly.

virtual void	cycle (std::function< void(const moteus::Output &)> callback)=0
	Spin a new communication cycle. More...

virtual void	reset (const Dictionary &config)=0
	Reset interface. More...

virtual void	observe (Dictionary &observation) const =0
	Write servo and IMU observations to dictionary. More...

const ServoLayout &	servo_layout () const noexcept
	Get servo layout.

const std::map< int, int > &	servo_bus_map () const noexcept
	Map from servo ID to the CAN bus the servo is connected to.

const std::map< int, std::string > &	servo_name_map () const noexcept
	Map from servo ID to joint name.

std::vector< moteus::ServoCommand > &	commands ()
	Get servo commands.

const std::vector< moteus::ServoReply > &	replies () const
	Get servo replies.

moteus::Data &	data ()
	Get joint command-reply data. More...

void	reset_action (Dictionary &action)
	Reset action dictionary to the default action. More...

virtual void	process_action (const Dictionary &action)=0
	Process a new action dictionary. More...

void	write_position_commands (const Dictionary &action)
	Write position commands from an action dictionary. More...

void	write_stop_commands () noexcept
	Stop all servos. More...

void	observe_imu (Dictionary &observation) const
	Observe IMU measurements. More...

Public Attributes
double	inertia_randomization_
	Mass randomization epsilon.

std::map< int, double >	nominal_masses
	Nominal masses of the robot links.

std::map< int, double[3]>	nominal_inertia
	Nominal inertia diagonal of the robot links.

Additional Inherited Members
Protected Attributes inherited from upkie::cpp::actuation::Interface
moteus::Data	data_
	Pointers to the memory shared with the CAN thread. More...

ImuData	imu_data_
	IMU data.

Detailed Description

Actuation interface for the Bullet simulator.

Constructor & Destructor Documentation

◆ BulletInterface()

upkie::cpp::actuation::BulletInterface::BulletInterface ( const Parameters & params )

explicit

Initialize interface.

Parameters

[in] params Interface parameters.

Exceptions

std::runtime_error If the simulator did not start properly.

Member Function Documentation

◆ compute_joint_torque()

double upkie::cpp::actuation::BulletInterface::compute_joint_torque	(	const std::string &	joint_name,
		const double	feedforward_torque,
		const double	target_position,
		const double	target_velocity,
		const double	kp_scale,
		const double	kd_scale,
		const double	maximum_torque
	)

Reproduce the moteus position controller in Bullet.

Parameters

[in]	joint_name	Name of the joint.
[in]	feedforward_torque	Feedforward torque command in [N m].
[in]	target_position	Target angular position in [rad].
[in]	target_velocity	Target angular velocity in [rad] / [s].
[in]	kp_scale	Multiplicative factor applied to the proportional gain in torque control.
[in]	kd_scale	Multiplicative factor applied to the derivative gain in torque control.
[in]	maximum_torque	Maximum torque in [N m] from the command.

◆ cycle()

void upkie::cpp::actuation::BulletInterface::cycle ( std::function< void(const moteus::Output &)> callback )

finalvirtual

Spin a new communication cycle.

Parameters

callback Function to call when the cycle is over.

The callback will be invoked from an arbitrary thread when the communication cycle has completed. All memory pointed to by data must remain valid until the callback is invoked.

Implements upkie::cpp::actuation::Interface.

◆ get_angular_velocity_base_in_base()

Eigen::Vector3d upkie::cpp::actuation::BulletInterface::get_angular_velocity_base_in_base ( ) const

noexcept

Get the groundtruth floating base angular velocity.

Note: This function is only used for testing and does not need to be optimized.

◆ get_joint_angles()

Eigen::VectorXd upkie::cpp::actuation::BulletInterface::get_joint_angles ( )

noexcept

Get the groundtruth vector of joint angles.

Note: This function is only used for testing and does not need to be optimized.

◆ get_linear_velocity_base_to_world_in_world()

Eigen::Vector3d upkie::cpp::actuation::BulletInterface::get_linear_velocity_base_to_world_in_world ( ) const

noexcept

Get the groundtruth floating base linear velocity.

Note: This function is only used for testing and does not need to be optimized.

◆ get_position_link_in_world()

Eigen::Vector3d upkie::cpp::actuation::BulletInterface::get_position_link_in_world ( const std::string & link_name )

Compute the position of a link frame in the world frame.

Parameters

[in] link_name Name of the link in the robot description.

◆ get_transform_body_to_world()

Eigen::Matrix4d upkie::cpp::actuation::BulletInterface::get_transform_body_to_world ( int body_id ) const

noexcept

Get a groundtruth body transform.

Parameters

[in] body_id The body id as given when loading the body in bullet.

◆ observe()

void upkie::cpp::actuation::BulletInterface::observe ( Dictionary & observation ) const

overridevirtual

Write actuation-interface observations to dictionary.

Parameters

[out] observation Dictionary to write to.

Implements upkie::cpp::actuation::Interface.

◆ process_action()

void upkie::cpp::actuation::BulletInterface::process_action ( const Dictionary & action )

overridevirtual

Process a new action dictionary.

Parameters

[in] action Action to read commands from.

Implements upkie::cpp::actuation::Interface.

◆ process_forces()

void upkie::cpp::actuation::BulletInterface::process_forces ( const Dictionary & external_forces )

Process a dictionary of additional external forces.

Parameters

[in] external_forces Dictionary to read forces from.

Note that Bullet clears external forces after each simulation step.

◆ reset()

void upkie::cpp::actuation::BulletInterface::reset ( const Dictionary & config )

overridevirtual

Reset interface.

Parameters

[in] config Additional configuration dictionary.

Implements upkie::cpp::actuation::Interface.

◆ reset_base_state()

void upkie::cpp::actuation::BulletInterface::reset_base_state	(	const Eigen::Vector3d &	position_base_in_world,
		const Eigen::Quaterniond &	orientation_base_in_world,
		const Eigen::Vector3d &	linear_velocity_base_to_world_in_world,
		const Eigen::Vector3d &	angular_velocity_base_in_base
	)

Reset the pose and velocity of the floating base in the world frame.

Parameters

[in]	position_base_in_world	Position of the base in the world frame.
[in]	orientation_base_in_world	Orientation of the base in the world frame.
[in]	linear_velocity_base_to_world_in_world	Linear velocity of the base in the world frame.
[in]	angular_velocity_base_in_base	Body angular velocity of the base (in the base frame).

◆ reset_joint_angles()

void upkie::cpp::actuation::BulletInterface::reset_joint_angles ( const Eigen::VectorXd & joint_configuration )

Reset joint angles.

Parameters

[in] joint_configuration Joint configuration vector.

The documentation for this class was generated from the following files:

upkie/cpp/actuation/BulletInterface.h
upkie/cpp/actuation/BulletInterface.cpp

Classes

Public Member Functions

Public Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ BulletInterface()

Member Function Documentation

◆ compute_joint_torque()

◆ cycle()

◆ get_angular_velocity_base_in_base()

◆ get_joint_angles()

◆ get_linear_velocity_base_to_world_in_world()

◆ get_position_link_in_world()

◆ get_transform_body_to_world()

◆ observe()

◆ process_action()

◆ process_forces()

◆ reset()

◆ reset_base_state()

◆ reset_joint_angles()