[LANGUAGE INCOMPATIBILITY] Missing default value for damping in DQ_ClassicQPController for Python

[anachristinaac]

Description of the missing/unexpected functionality

When using the DQ_ClassicQPController, the MATLAB version defines a default value (0.001) for the damping variable, but the Python version does not.

Python behavior

PYTHON SCRIPT

from dqrobotics import *
from dqrobotics.solvers import DQ_QuadprogSolver
from dqrobotics.robot_control import DQ_ClassicQPController
from dqrobotics.robots import KukaLw4Robot

robot = KukaLw4Robot.kinematics()
solver = DQ_QuadprogSolver()
controller = DQ_ClassicQPController(robot, solver)
print(controller.get_damping())

PYTHON OUTPUT

7.73974598944389e+228

Matlab behavior

MATLAB SCRIPT

robot = KukaLwr4Robot.kinematics();
solver = DQ_QuadprogSolver;
controller = DQ_ClassicQPController(robot, solver);
controller.get_damping()

MATLAB OUTPUT

1.0000e-03

Environment:

• OS: Ubuntu 22.04.4 LTS
• dqrobotics version MATLAB: commit e455c66
• MATLAB version: R2023b
• dqrobotics version Python: 23.4.0a22
• Python version: 3.10.12

[juanjqo]

@anachristinaac thank you for letting us know! It looks like it is an issue in the C++ version.

@mmmarinho I proposed a PR in C++ to fix this language incompatibility. I tested both C++ and Python locally.

Minimal example:

from dqrobotics.solvers import DQ_QuadprogSolver
from dqrobotics.robot_control import DQ_ClassicQPController
from dqrobotics.robots import KukaLw4Robot


def main() -> None:
    robot = KukaLw4Robot.kinematics()
    solver = DQ_QuadprogSolver()
    controller = DQ_ClassicQPController(robot, solver)
    print(controller.get_damping())


if __name__ == "__main__":
    main()

Output:

0.001

#include <iostream>
#include <dqrobotics/robots/KukaLw4Robot.h>
#include <dqrobotics/robot_control/DQ_ClassicQPController.h>
#include <dqrobotics/solvers/DQ_PROXQPSolver.h>

using namespace DQ_robotics;


int main()
{
    auto robot = std::make_shared<DQ_SerialManipulatorDH>(KukaLw4Robot::kinematics());
    auto solver = std::make_shared<DQ_PROXQPSolver>();
    auto controller = DQ_ClassicQPController(robot, solver);
    auto damping = controller.get_damping();
    std::cout<<damping<<std::endl;
}

Output:

0.001

[mmmarinho]

Fixed with dqrobotics/cpp#67.

If needed, please re-open the issue.