Quanser Haptics 2 DOF Pantograph

This repository contains C code used to drive the now discontinued Quanser Haptics 2 DOF Pantograph with the Quanser AMPAQ-L2 Linear Current Amplifier, Quanser QPID Terminal Board and Quanser HIL SDK.

A simple haptics scenario consisting of a virtual spring-damper wall is implemented to demonstrate the capabilities of the 2 DOF Pantograph as a haptic device when used with more recent Quanser driver hardware.

Reasoning

The 2 DOF Pantograph was originally sold with the QPA-L2-E Multi-Channel Linear Amplifier, which is also deprecated, and which was attached to a data acquisiton card that would probably not be compatible with most modern PC motherboards.

The QPID, which is used in this project as a DAC, is also deprecated, but Quanser sells other very imilar DACs which would be compatible with this project, with just a few minor changes in panto_demo.c.

Requirements

This software has only been tested with the Windows version of the Quanser HIL SDK, though a Linux version does exist that should be compatible, with some changes in panto_demo.c to replace dependencies to Windows.h.

First, install the Quanser HIL SDK and ensure that the environment variable %HIL_DIR% is set to the appropriate location. This should be C:\Program Files\Quanser\HIL SDK.

Next, install Microsoft Visual Studio Community, as the HIL SDK only supports the msvc compiler.

Finally, install CMake, which will be used to build the project.

To run the python scripts in the design_scripts/ folder, install the latest version of Python. Make sure to select the "Add to PATH" option when going through the installation menus.

Then, run the following commands from within design_scripts/ to setup a virtual environment:

> py -m venv env
> env\Scripts\activate.bat
> (env) pip install -r requirements.txt

Usage

To compile the project, first create a directory called build/ inside the root of the repository, navigate to it, and run CMake to generate the required Visual Studio projects:

> mkdir build
> cd build
> cmake ..

Then run

cmake --build .

from within build/ to compile the project.

The main executable is build/src/Debug/PantograpDemo.exe.

If the Pantograph is connected to the AMPAQ and the QPID, as shown in this schematic, it will wait 5 seconds for the user to place the pantograph end effector in the homing position before running the controller. After execution, the program will save a CSV file containing the results in a data folder that will be created in this repo.

It will have a name like panto_<TIMESTAMP>.csv

To run any of the python scripts, run the following commands

> env\Scripts\activate.bat
> cd ..
> (env) py -m <insert_script_name_here>.py

from within design_scripts/.

These scripts plot useful graphs from data produced by PantograpDemo.exe.

Outputs

The CSV output has the following columns

Column	Description
t	Timestamp (s)
target_current_0	Saturated target current for motor 0 (A)
target_current_1	Saturated target current for motor 1 (A)
current_0	Measured motor 0 current (A)
current_1	Measured motor 1 current (A)
filt_current_0	Filtered motor 0 current (A)
filt_current_1	Filtered motor 1 current (A)
axis_0_phi_1	Angle between x-axis and linkage 1 (rad), driven by motor 0
axis_0_phi_3	Angle between x-axis and linkage 3 (rad), driven by motor 1
pos_x	End effector cartesian coordinate on x-axis (m)
pos_y	End effector cartesian coordinate on y-axis (m)
force_x	Target force to produce on end effector in x-axis direction (m)
force_y	Target force to produce on end effector in y-axis direction (m)
axis_0_vel_phi_1	Angular velocity (rad/s) of axis_0_phi_1
axis_0_vel_phi_3	Angular velocity (rad/s) of axis_0_phi_3
vel_x	End effector velocity in x-axis direction (m/s)
vel_y	End effector velocity in y-axis direction (m/s)

Acknowledgments

Thanks go to Steven Dahdah, who's code in the quanser_qube Github repo was for the most part copied directly into this repo, and in the main C file was somewhat modified to fit this specific application.