FootPedals.md

• Introduction
• dVRK controller compatible foot pedals
  • Material
  • Wiring
  • Software configuration
• USB foot pedals
  • Compilation
  • Configuration

Introduction

This page presents alternative foot pedals that can be used the dVRK controllers and software. There are multiple cases where one might need some extra foot pedals:

• Splitting your system into two systems, e.g. using the MTMR and PSM1 for one setup and the MTML and PSM2 for another setup.
• Using extra inputs from a patient's side assistant.
• Using the dVRK software without any dVRK controller. For example, using a Force Dimension haptic device on the surgeon's side and the patient cart in simulation.

We present two different options that are supported with the dVRK controllers and/or software:

• Foot pedals that connect to the dVRK controllers
• USB foot pedals with joystick emulation (most cheap foot pedals)

dVRK controller compatible foot pedals

The goal of this section is to show how to build some dVRK compatible foot pedals. These can only be used with the dVRK controllers and can't be connected directly to a PC. This can be useful if you're splitting your dVRK into two systems (e.g., one MTM/PSM on one controller and the other MTM/PSM an another controller) or if you use a spare PSM with an alternate master arm (e.g., PSM and Force Dimension master).

The design described below is based on up to 3 pairs of foot pedals. One can use one, two or three pairs as needed. The wiring allows to swap the pedals without any software reconfiguration. This configuration is also pin compatible with the real da Vinci foot pedals. By default, the first pair of foot pedals is wired as the right two pedals on the daVinci (from left to right: bi-coag and coag) and the second pair of pedals is wired as the left two pedals (from left to right: clutch and camera):

Material

• One (or two or three) pairs of foot pedals. We found that these pedals are nicely built and heavy enough to not slide on the floor when used: https://smile.amazon.com/dp/B077NM69DL The following model might work as well but we didn't try: https://smile.amazon.com/Plastic-Double-Action-Switch-Pedal/dp/B077NK8XYZ
• Cables: https://smile.amazon.com/Monoprice-6ft-DB15-Molded-Cable/dp/B002LWJ7TA You will need 2 to 4 cables.

Wiring

To minimize the amount of soldering we simply cut one DB 15 extension cable in two (one cable per foot pedal). The wiring for two foot pedals (i.e., without the optional 3rd foot pedal for camera +/-) can be seen in the following picture (credit: Christian Hernandez):

The complete wiring can be found in this PDF file or in Altium Designer format.

Software configuration

There is no software specific configuration, just use the IO files used with the Intuitive Surgical foot pedals.

USB foot pedals

Note: not all USB foot pedals are supported at that point. To easily integrate the foot pedal with cisst/SAW, we're using the sawJoystick component. See README.md for the sawJoystick for more information.

Compilation

To compile the sawJoystick component, we strongly recommend to use wstool to get all the source code under your catkin workspace. You can find the .rosinstall file for the sawJoystick code under the sawJoystick/ros directory on github.

Configuration

First you will need to configure the dVRK console to use the sawJoystick component. Your console.json file should contain:

    "component-manager": {
        "components":
        [
            {
                "shared-library": "sawJoystick",
                "class-name": "mtsJoystick",
                "constructor-arg": {
                    "Name": "joystick"
                },
                "configure-parameter": "misc/sawJoystickConfiguration.json"
            }
        ]
    }
    ,
    "console-inputs":
    {
        "operator-present": {
            "component": "joystick",
            "interface": "OperatorPresent"
        }
        ,   "clutch": {
            "component": "joystick",
            "interface": "Clutch"
        }
    }

Then you need to configure the sawJoystick component so that buttons are mapped to names that match the dVRK foot pedal names (e.g. "OperatorPresent", "Clutch"...). We provide an example of sawJoystick configure for the dVRK in share/misc/sawJoystickConfiguration.json:

{
    "converters":
    [
        {
            "type": "interface-provided-button",
	    "index-input": 1,
            "interface-name": "OperatorPresent"
        }
	,
        {
            "type": "interface-provided-button",
	    "index-input": 0,
            "interface-name": "Clutch"
        }
    ]
    ,
    "device": "/dev/input/js0"
}

To test which "device" and "index-input" to use, you can run the example application that comes with sawJoystick: sawJoystickQtExample. To test different devices, you can use the -d option (e.g. -d /dev/input/js0).