Parameters

Basic Parameters

bool enabled[not required]

Default: False
Brief: Initial state of the controller

double controller_frequency[not required]

Default: 10.0
Brief: Frequency of the controller

string tf_prefix[not required]

Default: ‘’
Brief: Transform Tree prefix

string odometry_source

Default: odometry
Brief: Odometry topic name

string world_link[not required]

Default: world
Brief: Transform tree worl link name

string cg_link[not required]

Defeault: cg_link
Brief: Center of gavity transform tree link name

Control Allocation Parameters

string generator_type

Brief: Defines the control allocation matrix generation method.

Depending on the parameter, it is either auto generated or user defined

Option: tf Control allocaiton matrix generated using Transform Tree. If this option is selected, user must define actuator links in the thruster_ids parameter.|
Option: user User provides the control allocation matrix

complex control_allocation_matrix

Brief: User defined control allocation matrix.

User defines the control allocation matrix as vectors per actuator. Those vectors are so-called contribution vectors.

vector<double> [anonymous]

Brief: Contribution vector for given actuator

\texttt{<actuator\_name>} \leftarrow [\phi, \theta, \psi, u, v, w]

Example control_allocation_matrix configuration.

control_allocation_matrix:
    main:
        [0.0, 0.0, 0.0, 1.0, 0.0, 0.0]
    horizontal:
        [0.0, 0.0, 0.48, 0.0, 1.0, 0.0]
    vertical:
        [0.0, 0.39, 0.0, 0.0, 0.0, -1.0]

complex control_tf

Brief: Transform tree link names for actuators

If generator_type parameter is set to tf, the mvp_control will look for actuator links in the transform tree. Transform tree link names is required to generate the control allocaiton matrix.

string [anonymous]

Brief: Trasform tree link name for the actuator

Example

control_tf:
    main: main_thruster_link
    horizontal: horizontal_thruster_link
    vertical: vertical_thruster_link

Actuator Parameters

vector<string> thruster_ids

Brief: Arbitrary names for actuators

The user must declare arbitrary id for actuators. Each thruster has its unique ID. These unique IDs will be used for configuring them. In the rest of the configuration file, those IDs must match.

Example

thruster_ids:
  - main
  - horizontal
  - vertical

complex thruster_command_topics

Brief: Control command topics for each actuator.

Control command for the actuator will be published under the topic defined with this parameter. The topic will publish the control command in std_msgs/Float64 format.

string [anonymous]

Brief: Control commad topic for an actuator

Example configuration

thruster_command_topics:
    main: control/thruster/main
    horizontal: control/thruster/horizontal
    vertical: control/thruster/vertical

complex thruster_force_topics

Brief: Topic for controller force output for each actuator.

This topic will publish requested force from each actuator in Newtons. The topic will publish the control command in std_msgs/Float64 format.

string [anonymous]

Brief: Force topic for an actuator

Example configuration

thruster_force_topics:
    main: control/force/main
    horizontal: control/force/horizontal
    vertical: control/force/vertical

complex thruster_polynomials

Brief: Thrust curve for each thruster

Control allocation computes the demanded force from each actuator. Thrust curves help converting force into control command. This could be a [1100,1900] PWM value or simple [-1.0,1.0] value.

vector<float> [anonymous]

Brief: Thrust curve for thruster defined

For given thrust curve, f(x), thrust polynomial is set as follows.

f(x) = a_n x^n + a_{n-1} x^{n-1} + ... + a_1 x + a_0 \\ \text{Thruster Polynomial} \leftarrow [a_0, a_1, ... ,a_{n-1}, a_n]

Example Configuration

thruster_polynomials:
    main:       [0.06165, 20.32, 9.632, 93.05, -2.856, -74.1]
    horizontal: [0.06165, 20.32, 9.632, 93.05, -2.856, -74.1]
    vertical:   [0.06165, 20.32, 9.632, 93.05, -2.856, -74.1]

Template for thruster polynomial configuration

thruster_polynomials:
    {{ Thruster ID }}: [{{a0}, {{a1}}}, ...,{{an}}]
    {{ Thruster ID }}: [{{a0}, {{a1}}}, ...,{{an}}]
    ...

complex thruster_limits

Brief: Force limits for each thruster

complex [anonymous]

Brief: Maximum and minimum limits for given thruster

float max

Brief: maximum limit for the given thruster

float min

Brief: minimum limit for the given thruster

Example

thruster_limits:
    main:
        max: 40
        min: -30
    horizontal:
        max: 20
        min: -20
    vertical:
        max: 20
        min: -20

Control Law Parameters

complex control_modes

Brief: Control modes with PID gains

complex [anonymous]

Brief: Control mode

Control mode name is given with this parameter. Target degree of freedoms and PID gains described under each control mode. MVP Controller can be configured with more than one control mode.

complex [anonymous]

Brief: Target degree of freedoms and their PID gains

Target degree of freedoms of a control mode with its PID gains. This complex object can only have members that are described in the table below. Each ‘member’ of this complex object contains PID gains.

Possible values for target degree of freedoms
Target DOFs	Keyword	SNAME Symbol
Position in X axis	`x`	x
Position in Y axis	`y`	y
Position in Z axis	`z`	z
Orientation around X axis	`roll`	\phi
Orientation around Y axis	`pitch`	\theta
Orientation around Z axis	`yaw`	\psi
Linear speed on X axis	`surge`	u
Linear speed on Y axis	`sway`	v
Linear speed on Z axis	`heave`	w
Angular speed around X	`roll_rate`	\dot{\phi}
Angular speed around Y	`pitch_rate`	\dot{\theta}
Angular speed around Z	`yaw_rate`	\dot{\psi}

float p: P gain for PID controller

float i: I gain for PID controller

float d: D gain for PID controller

float i_max: Maximum integral value

float i_min: Minimum interal value

Example configuration is given in the code snippet below. In the code snippet three control modes are configured. The first control mode is flight mode that controls pitch, yaw and surge. Second control mode is hold that controls x and y. The third and the last contol mode is kill. This is a special setting that allows user to create control modes that doesn’t control any degree of freedoms. It is particularly useful when creating safety behaviors.

Simply put, first indentation after control_modes directive starts to create a new control mode. And then the next indentation is to describe target degree of freedoms.

Example control mode configuration

control_modes:
    flight:
        pitch:    {p: 5.0,    i: 1.0,   d: 2.0,   i_max: 10, i_min: -10}
        yaw:      {p: 5.0,    i: 0.5,   d: 30.0,  i_max: 20, i_min: -20}
        surge:    {p: 10.0,   i: 3.0,   d: 5.0,   i_max: 10, i_min: -10}

    hold:
        x:        {p: 2.0,    i: 0.5,   d: 1.0,   i_max: 10, i_min: -10}
        y:        {p: 2.0,    i: 0.5 ,  d: 1.0,   i_max: 10, i_min: -10}

    kill: false