gzjoint

Assign and retrieve Gazebo model joint information

Since R2021a

Syntax

List = gzjoint("list",modelname)

[Status,Message] = gzjoint("set",modelname,jointname,Name,Value)

[Output1,...,OutputN] = gzjoint("get",modelname,jointname,params)

Description

List = gzjoint("list",modelname) returns and displays a list of joint names List of the specified Gazebo model modelname.

example

[Status,Message] = gzjoint("set",modelname,jointname,Name,Value) assigns values to the joint parameters using one or more name-value pair arguments for the specified Gazebo model modelname and the joint jointname. The function returns the status of the value assignments Status and the message of their success and failure Message. For example, gzjoint("set","unit_box","joint","Position",[2 2 0.5]) sets the position of the joint in the model unit_box.

[Output1,...,OutputN] = gzjoint("get",modelname,jointname,params) retrieves values of the joint parameters using one or more parameter names, params, for the specified Gazebo model modelname and the joint jointname. The function returns one or more outputs, Output1,...,OutputN, corresponding to the specified parameter names.

Examples

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Perform Co-Simulation Between MATLAB and Gazebo

Open Live Script

Set up a simulation between MATLAB and Gazebo, receive data from Gazebo, and send commands to Gazebo.

Prerequisite

Follow the instructions in Perform Co-Simulation Between Simulink and Gazebo to download the Linux virtual machine (VM) with Gazebo and set up multiSensorPluginTest.world.

Configure and Perform Gazebo Co-Simulation

Initialize connection settings and check connectivity with the Gazebo plugin running on 192.168.198.129 and port 14581.

gzinit("192.168.198.129",14581)

Assign and Retrieve Gazebo Model Information

List the models available in the Gazebo world.

modelList = gzmodel("list")

modelList = 1×11 string
    "ground_plane"    "unit_box"    "camera0"    "camera1"    "depth_camera0"    "depth_camera1"    "imu0"    "imu1"    "hokuyo0"    "hokuyo1"    "velodyne"

Assign values to the Position and SelfCollide parameters of the unit_box model.

[status,message] = gzmodel("set","unit_box","Position",[2 2 0.5],"SelfCollide","on")

status = 1×2 logical array

   1   1

message = 1×2 string
    "Position parameter set successfully."    "SelfCollide parameter set successfully."

Retrieve the values of the Position and SelfCollide parameters of the unit_box model.

[position,selfcollide] = gzmodel("get","unit_box","Position","SelfCollide")

position = 1×3

                         2                         2           0.4999999999951

selfcollide = logical
   1

Assign and Retrieve Gazebo Model Link Information

List the links available in the unit_box model.

linkList = gzlink("list","unit_box")

linkList = 
"link"

Assign values to the link parameters Mass and Gravity of the link link in the unit_box model.

[status,message] = gzlink("set","unit_box","link","Mass",2,"Gravity","off")

status = 1×2 logical array

   1   1

message = 1×2 string
    "Mass parameter set successfully."    "Gravity parameter set successfully."

Retrieve the values of the link parameters Mass and Gravity of the link link in the unit_box model.

[mass,gravity] = gzlink("get","unit_box","link","Mass","Gravity")

mass = 
     2

gravity = logical
   0

Assign and Retrieve Gazebo Model Joint Information

List the joints available in the unit_box model.

jointList = gzjoint("list","unit_box")

jointList = 
"joint"

Assign a value to the joint parameter Damping of the axis Axis0 for the joint joint in the unit_box model.

[status,message] = gzjoint("set","unit_box","joint","Axis","0","Damping",0.25)

status = logical
   1

message = 
"Damping parameter set successfully."

Retrieve the value of the joint parameter Damping of the axis Axis0 for the joint joint in the unit_box model.

damping = gzjoint("get","unit_box","joint","Axis0","Damping")

damping = 
                      0.25

Reset all Gazebo model configurations.

gzworld("reset")

Input Arguments

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`modelname` — Gazebo model name
string scalar | character vector

Gazebo model name, specified as a string scalar or character vector.

Data Types: char | string

`jointname` — Associated joint name
string scalar | character vector

Associated joint name, specified as a string scalar or character vector.

Data Types: char | string

`params` — Gazebo model joint parameters
string scalars | character vectors

Gazebo model joint parameters, specified as a comma-separated list of string scalars or character vectors. Specify the list of parameters you want to retrieve the values, from these tables.

Gazebo model joint axis parameters for Axis0 or Axis1, specified as the comma-separated arguments consisting of "Axis0" or "Axis1", respectively, and one or more of the options in this table.

Option Name	Description
`"Angle"`	Get the angle parameter of the Gazebo model joint axis for `Axis0` or `Axis1`.
`"Damping"`	Get the damping parameter of the Gazebo model joint axis for `Axis0` or `Axis1`.
`"Friction"`	Get the friction parameter of the Gazebo model joint axis for `Axis0` or `Axis1`.
`"XYZ"`	Get the position of the Gazebo model joint axis for `Axis0` or `Axis1`.

Gazebo model joint parameters:

Parameters	Description
`"CFM"`	Get the CFM parameter of the Gazebo model joint.
`"FudgeFactor"`	Get the fudge factor parameter of the Gazebo model joint.
`"Orientation"`	Get the orientation parameter of the Gazebo model joint.
`"Position"`	Get the position of the Gazebo model joint.
`"SuspensionCFM"`	Get the suspension CFM parameter of the Gazebo model joint.
`"SuspensionERP"`	Get the suspension ERP parameter of the Gazebo model joint.

Example: [ang,damp,cfm,pos] = gzjoint("get","unit_box","joint","Axis0","Angle","Damping","CFM","Position")

Data Types: char | string

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: For example, gzjoint("set","unit_box","joint","Position",[2 2 0.5]) sets the position of the joint in the model unit_box.

`Axis` — Gazebo model joint axis parameters
`"0"` | `"1"`

Gazebo model joint axis parameters, specified as the comma-separated pair consisting of 'Axis' and either "0" or "1". Then, specify one or more of the options in this table as the comma-separated pair consisting of an option name and its value.

Option Name	Description
`"Angle"`	Set the angle parameter of the Gazebo model joint axis as a numeric scalar in radians.
`"Damping"`	Set the damping parameter of the Gazebo model joint axis as a numeric scalar in newton meter second per radians.
`"Friction"`	Set the friction parameter of the Gazebo model joint axis as a numeric scalar in newton.
`"XYZ"`	Set the position of the Gazebo model joint axis as a three-element vector of the form `[X Y Z]` in meters.

Example: [status,message] = gzjoint("set","unit_box","joint","Axis","0","Damping",0.25)