Simulating human handling of a surgical instrument

Help & Support Professional Robots
1

Morning community!

Thank you for taking the time to help, I really appreciate it.
I’m trying to create a simulator to test the motion of surgical instruments in space, no actual cutting, etc.,
So far I would say that I need:

  1. a 6DOF robotic arm
  2. a way to record the motion of a human to be replicated by the robot
  3. a way to add human inaccuracies

Starting from point 1, I know that they payload should be > 150grams, < 300grams.
What about speed? Every video that I saw on the platform shows fairly slow motions.
How can we determine the overall speed of the end effector in relation to the base?

  1. From some reading this should be called “record and play”, should it be specified in the robot
    or it’s something that can be added regardless?

  2. I’d like to simulate the “vibrations” introduced by a human, a low frequency shaking, would that be easy with a robotic arm?

Thank you everyone for any tip on the right direction or documentation to read to help me learn more on this.

Riccardo

2

@signo Welcome to the RobotShop Community.

  1. What is your budget for this type of arm?
  2. What max reach do you need?
  3. What accuracy (before you add the “shaking”) do you need?

When you indicate that “every video you saw” shows fairly slow motion - which arms did you see?

Q1) How can we determine the overall speed of the end effector in relation to the base?

Some manufacturers provide this information, otherwise you can calculate it based on the dimensions and the angular speed of each joint.

Q2) From some reading this should be called “record and play”, should it be specified in the robot or it’s something that can be added regardless?

Normally this needs to be a feature which is provided by the manufacturer and is not easy to add after-sale. It also sounds like “teach mode”.

Q3) I’d like to simulate the “vibrations” introduced by a human, a low frequency shaking, would that be easy with a robotic arm?

You’ll need to get into trajectory / path programming. This is not a feature which any robot arm manufacturers would want to have in their arm (arms are supposed to be precise and smooth).

1 Like
3

Thank you @cbenson,

Sorry that I missed your reply, I’ll need to set the notifications.

  1. Budget is <= $10k (for the ideal solution)
  2. Max reach should be about 12 inches but it’s flexible, it’s mostly dictated by the size of the instrument.
  3. +/- 5mm should be enough (*we can use our optical tracking to have an accurate log of the actual motion)

I was watching the ViperX 250 Robot Arm and the other products in the same category.

Would you know which manufacturers I should look at? Would anything on Robotshop fit my application?

Best,
Riccardo

1 Like
4

You’ll likely be looking at these two categories:


Requiring 6DoF and <$10k limits the selection to the following:





(and several others from Trossen)

One arm that stands out from others, though does not meet your other specs (not 6DoF, or the accuracy), is the following:

This arm seems to incorporate the human control aspect you want, though not to “surgical accuracy”.

5

Thanks a lot @cbenson for your quick reply!

I checked the units you listed.
What about the function “record and play”, will these units do that?

I have actually reached out to Trossen and the only unit with the “record and play” is ~$15k.

I am not familiar with this field. Is something like that worth $15k?

Best,
Riccardo

6

The XArm is actually from uFactory, and although RobotShop is partnered with uFactory, we do not offer that line of professional arms. The xArm competes with arms like those from Universal Robots (UR3, UR5) and the technology involved in their design and construction does indeed make them worth the money (in fact, the price of the xArm series is about the least expensive you can pay for such an arm).

However, if you can buy an exotic sports car at half price (like $75k for something like a Ferrari) but really only need a small sedan, is it worth spending the money? Only you can decide.

Record and Play requires that the actuator have built-in position feedback (which almost all of these have), but it’s a question of where the default software includes that feature. Normally if you can program, you can create it yourself, but if not, then yes, you must rely on what the manufacturer provides. Not sure about each of the arm above - you’ll need to check one by one, though in most cases the software is free to download and use.

Cheap: These tend to use RC servos which don’t have feedback, have low accuracy and are intended to provided the most entry level experience for using a robotic arm. Prices range from $40 to ~$600.

Hobby-grade robotic arms with feedback: Lynxmotion 4DoF, and Trossen (which use Dynamixel smart servos) tend to be $800 to $3k (depending on the power / cost of the servos)

Semi-pro arms (and"Cobot" arms) like the xArm, Dobot’s CR series and Universal Robot’s UR series are ballpark $5k to $50k, though you can find second hand models for sale.

Industrial arms: too expensive, too dangerous, often too diccifult to use without support from the manufacturer.

Based on your description, you’d be looking at in the hobbyist and semi-pro selection.

7

Thank you so much @cbenson!!

I know what to look for now. My team and I can definitely code.
I wasn’t sure if the servos needed some kind of special feature to let you move them “freely” but after reading your answer and using your keywords online I found other posts and I think that we should be able to use one of the units you mention and write our own “record and play”.

I’ll keep you posted on my progress

Best,
Riccard