package_template package

Submodules

package_template.pid module

Brief description of the pid module.

More advanced description of this module, e.g. This module contains a 1D PID controller and utilities for managing the gains and the controller parameters.

Copyright (c) 2017-2019, New York University and Max Planck Gesellschaft, License BSD-3-Clause

class package_template.pid.ConfigFileConfiguration

Bases: object

Path to default configuration file, relative to the pid package

relative_path = 'config/test_pid_gains.yaml'

class package_template.pid.DefaultConfiguration

Bases: object

PID configuration

Configuration object with default values for kp, kd and ki can be used as input argument to create an instance of PID

kp

Proportional gain.

kd

Derivative gain.

ki

Integral gain.

kd = 1

ki = 1

kp = 1

class package_template.pid.PythonPID(configuration)

Bases: object

Simple 1D PID controller

_configuration

The PID gains.

_integral

The integral term.

compute(position, velocity, position_target, delta_time)

Compute the force related to the pid controller.

This function is not stateless, as it performs integration. Call reset_integral() to reset the integral part.

Parameters

• position – Float – current position

• velocity – Float – current velocity

• position_target – Float – target position

• delta_time – Float – time passed since last measurement. Used for integral computation

Returns

Float – computed force

get_gains()

Get the gains in a dictionary, keys: “kp”, “kd” and “ki” :returns: Dict – The PID gains.

reset_integral()

Reset integral part of the PID to 0.0

class package_template.pid.RosConfiguration

Bases: object

ROS param configuration

This contains the name of the ros parameter server keys for the PID gains.

ROSPARAM_KP

Key for reading kp gain.

ROSPARAM_KD

Key for reading kd gain.

ROSPARAM_KI

Key for reading ki gain.

ROSPARAM_KD = 'kd'

ROSPARAM_KI = 'ki'

ROSPARAM_KP = 'kp'

package_template.pid.get_config_file_pid(config_file_path=None, verbose=True)

Reads a yaml file and return a corresponding PID controller.

Parameters

• config_file_path – str – Path to configuration file relative to the script where this function is defined is specified in the ConfigFileConfiguration object. If None, uses default config file (in config folder), else used specified path

• verbose – Bool – If True, prints path to config file used to standard output

Returns

PID – A PID based on gains read from default configuration file

package_template.pid.get_default_pid()

Factory for default PID controller.

See PID and see DefaultConfiguration.

Returns

PID – a new PID controller based on the DefaultConfiguration.

package_template.pid.get_ros1_params_pid(verbose=True)

Get a PID controller parameterized through ROS params

Assumes roscore is running and suitable parameters have been written in the server.

Parameters

verbose – Bool – True: prints (stdout) the ros parameters it reads.

Returns

PID – A PID object based on gains read from the ROS parameter server.

Module contents

package_template Contains an example of a python package.