Tool Generations

Introduction

As of May 2021, the dVRK hardware and software is designed to control the first generation da Vinci, aka Classic (see FAQ for details regarding da Vinci versions). On the patient's side, the PSM arms are designed to use interchangeable tools depending on the task (e.g. needle driver, scissor, grasper...). Since the da Vinci classic has been retired in 2012 it is getting harder to find tools for this model. Fortunately, when Intuitive Surgical introduced the da Vinci S (and later Si) the tools remained almost unchanged so it is possible to use S/Si tools with the dVRK Classic PSMs.

Part number

Instruments can be identified using their part number:

• First 6 digits: base part number
• Dash '-'
• Last 2 digits: version number
• Optional "T" letter: training instrument, same mechanical parameters but can be used more times (on clinical systems, irrelevant on dVRK)
• Letter Revision: 'A-Z' Example: 420093-03T Rev B

For the dVRK, we maintain a list of know/supported instruments in the file index.json under share/tool.

Differences between Classic and S/Si tools

The main differences are:

• Model number: both generation of tools are identified by a 6 digits number. Classic tool model numbers start with 400 while S/Si tool model numbers start with 420. For example, a classic large needle driver (LND) uses 400006 while a S/Si LND uses 420006.
• Length: S/Si tools are longer. We assume this is the main reason this new tool version was introduced. If you are curious, you should look at S/Si PSM arms, they have an interesting two stage translation link for insertion. This allows to "collapse" the arm when the tool is inserted and reduce the risk of collision between the arms outside the patient.
• Shape of the tool base plate and sterile adapter: since both the Classic and S/Si were commercially available at the same time, the tools have a different base plate to make sure a Classic tool can't be accidentally inserted on a S/Si PSM and a S/Si tool can't be inserted on a Classic PSM. To circumvent this with the dVRK, one can use a modified Classic sterile adapter that can accept a S/Si tool.

Sterile adapter for S/Si

To use a S/Si tool with the dVRK Classic PSM, one need to use a modified Classic sterile adapter. The modifications are a bit challenging so you should probably try to get some modified sterile adapters directly from ISI:

• Side grooves need to be deepen
• Ends of side grooves need to be cut to allow for a large tool
• Bottom lip needs to be removed
• Middle bar needs to be shaven but not too much otherwise the matting wheels might fall

Note: these mechanical modifications are on top of the electric modification that requires to short two pins on the back of the sterile adapter.

Tool parameters

As far a we can tell the only parameter that needs to change between a Classic and a S/Si tool is the shaft length. See for example the files share/tool/LARGE_NEEDLE_DRIVER_400006.json and share/tool/LARGE_NEEDLE_DRIVER_420006.json. For the first joint, DH:

• Classic: "D": 0.4162 (i.e. 41.62 cm)
• S/Si: "D": 0.4670 (i.e. 46.7 cm, 5.08 cm longer)

Newer Si instruments

ISI introduced a new mechanism for the instrument's roll sometime around 2020. Instead of using a cable, the roll is now controlled using a gear. This affects the coupling matrix used to convert actuator to joint values. The scaling factor is different and the direction is reversed. It is very important to make sure you have the correct instrument definition file if you're using the manual tool detection (see Tool Detection). You can check if you have a "geared" instrument by looking at the mating disks or the revision number on the cover.