Move the robot from a PC

This article shows how to move a Staubli robot from a PC, in C# or Python, on a CS8 or CS9 controller, without writing a VAL 3 program. It gives a complete program that powers the arm and moves the tool 20 mm down and back in a straight line.

A robot is dangerous machinery. Run this program on the emulator of Staubli Robotics Suite first. On a real robot, keep the speeds low and a person at the emergency stop.

Prerequisites

• The SDK is connected to the controller: see Connect to your robot.
• The controller is in remote mode, and no VAL 3 application moves the arm.
• The user of the connection has the right to move the arm.

Which move to choose

A joint move is usually the fastest when the path does not matter. Use MoveL and MoveC when the tool must follow a given path.

Example

using UnderAutomation.Staubli;
using UnderAutomation.Staubli.Soap.Data;

public class HowToMoveRobot
{
    static void Main()
    {
        
        var controller = new StaubliController();
        controller.Connect("192.168.0.254");

        // 1. Start from the current position and configuration
        double[] joints = controller.Soap.GetCurrentJointPosition(robot: 0);
        IForwardKinematics current = controller.Soap.ForwardKinematics(robot: 0, joints);

        // 2. Low speed limits for a first test
        var mdesc = new MotionDesc
        {
            Velocity = 0.1,
            Acceleration = 0.1,
            Deceleration = 0.1,
            TranslationVelocity = 0.05,
            RotationVelocity = 0.05,
            Config = current.Config,
        };

        // 3. Power the arm. The controller must be in remote mode.
        PowerReturnCode power = controller.Soap.SetPower(true);
        if (power != PowerReturnCode.Success)
            throw new InvalidOperationException($"Power refused: {power}");

        // 4. Straight line 20 mm down, then back
        Frame target = current.Position;
        double startZ = target.Pz;

        target.Pz = startZ - 0.020;
        IMoveResult down = controller.Soap.MoveL(robot: 0, target, mdesc);

        target.Pz = startZ;
        IMoveResult up = controller.Soap.MoveL(robot: 0, target, mdesc);

        if (down.ReturnCode != MotionReturnCode.Success || up.ReturnCode != MotionReturnCode.Success)
            controller.Soap.ResetMotion();

        controller.Disconnect();
        
    }
}

The program:

1. reads the current joints and computes the current frame and configuration of the arm;
2. sets low speed limits in the motion descriptor, and keeps the current configuration;
3. powers the arm, and stops if the controller refuses;
4. moves down 20 mm in a straight line, then back, and cancels the moves if one is refused.

The target is the current frame with a new Pz: the orientation of the tool does not change.

Wait for the end of a move

A move method returns the answer of the controller to the request, with an Id for the move. It does not tell that the arm has reached the target. To wait for the arm, read the position until it reaches the target. See How to get the position.

Troubleshooting

• SetPower returns OnlyInRemoteMode: put the controller in remote mode.
• The move returns NotReady: the arm is not ready to move, for example not powered. Power it, call ResetMotion() after an error, and send the move again.
• The move returns ParameterError: check the target and the values of the motion descriptor.
• The arm takes an unexpected path to a frame: set Config in the motion descriptor. fk.Config of the current position keeps the current configuration.

What to read next

• Motion: the reference of power, moves and motion descriptor.
• Kinematics: check that a target is reachable before you move.