Position

Read the current joints and the Cartesian position of a Staubli robot, for the flange or a tool, in the world frame or in another frame.

Joints and Cartesian position
Joints only
With a tool and a frame
Position of a joint configuration
Try it in the demo application
Reference

This page shows how to read the current position of a Staubli robot on a CS8 or CS9 controller: the joint values, and the Cartesian position of the flange or of a tool, in the world or in another frame.

Joints and Cartesian position

GetCurrentCartesianJointPosition(robot) returns the joints and the Cartesian position of the flange in the world frame, in one request.

var controller = new StaubliController();
controller.Connect("192.168.0.254");
// Joints and flange position of the first robot, in one request
CartesianJointPosition position = controller.Soap.GetCurrentCartesianJointPosition(robot: 0);

// Joint values, in radians
double[] joints = position.JointsPosition;

// Flange position in the world frame: X, Y, Z in meters, Rx, Ry, Rz in radians
CartesianPosition flange = position.CartesianPosition;
Console.WriteLine($"X={flange.X} Y={flange.Y} Z={flange.Z}");
Console.WriteLine($"Rx={flange.Rx} Ry={flange.Ry} Rz={flange.Rz}");
controller.Disconnect();
}

Click to see the full code

Value	Unit
`JointsPosition`, one value per axis	radians
`X`, `Y`, `Z`	meters
`Rx`, `Ry`, `Rz`	radians

Joints only

GetCurrentJointPosition(robot) returns only the joint values. Use it when you do not need the Cartesian position.

var controller = new StaubliController();
controller.Connect("192.168.0.254");
// Only the joints, in radians
double[] joints = controller.Soap.GetCurrentJointPosition(robot: 0);

for (int i = 0; i < joints.Length; i++)
    Console.WriteLine($"J{i + 1} = {joints[i] * 180 / Math.PI:F2} deg");
controller.Disconnect();
}

Click to see the full code

With a tool and a frame

By default, the Cartesian position is the one of the flange, in the world frame. Pass a tool and a frame to get the position of the tool center point in the frame of your part or table.

tool: position of the tool center point, given in the flange frame.
frame: position of the reference frame, given in the world frame.

var controller = new StaubliController();
controller.Connect("192.168.0.254");
// Tool center point, given in the flange frame: 120 mm along Z
var tool = new CartesianPosition { Z = 0.120 };

// Reference frame, given in the world frame: a table 500 mm in front of the robot
var frame = new CartesianPosition { X = 0.500 };

CartesianJointPosition position = controller.Soap.GetCurrentCartesianJointPosition(robot: 0, tool, frame);

// Position of the tool center point in the table frame
CartesianPosition tcp = position.CartesianPosition;
controller.Disconnect();
}

Click to see the full code

Pass null (None in Python) for the flange or for the world frame.

Position of a joint configuration

To get the Cartesian position of joint values that are not the current ones, use the forward kinematics: see Kinematics.

Try it in the demo application

Everything on this page can be tried without writing code, in the Get current position page of the demo application.

Get current position page of the Staubli SDK demo application

The demo application is open source. The C# source of this page is CurrentPositionControl.cs.

Reference

Methods of SoapClientBase :

// Get the Cartesian position and joint positions of a robot
CartesianJointPosition GetCurrentCartesianJointPosition(int robot = 0, CartesianPosition tool = null, CartesianPosition frame = null);

// Get the current joint position of a robot
double[] GetCurrentJointPosition(int robot = 0);

Class

CartesianJointPosition

C#Python

Represents the joint positions and the Cartesian position of a robot end effector.

Member	Type	Description
CartesianJointPosition() Constructor
CartesianPosition Property	CartesianPosition	The Cartesian position of the robot end effector.
JointsPosition Property	double[]	The joint positions in radians.
Equals(object) Method	bool
GetHashCode() Method	int
ToString() Method	string

Class

CartesianPosition

C#Python

Represents a Cartesian position with X, Y, Z translation and Rx, Ry, Rz rotation components.

Member	Type	Description
CartesianPosition() Constructor		Initializes a new instance of the `CartesianPosition` class.
Rx Property	double	Rotation around the X axis (radians).
Ry Property	double	Rotation around the Y axis (radians).
Rz Property	double	Rotation around the Z axis (radians).
X Property	double	X translation component (m).
Y Property	double	Y translation component (m).
Z Property	double	Z translation component (m).
Equals(object) Method	bool
GetHashCode() Method	int
ToString() Method	string

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Position

Joints and Cartesian position

Joints only

With a tool and a frame

Position of a joint configuration

Try it in the demo application

Reference