Hello dear Prof. Piltan

As a  good machine tool, for example, can

routinely measure and fabricate parts to a precision of ( 2.5 micro m )

( 0:001 in). and As the tendencies in that field are toward a controller with:

1. simplicity,

2. potentially cheaper implementations,

3. a more direct coupling to the human’s natural kines-thetic senses

4. straightforward integration into an existing application environment, and

5. greater “immediacy” for the human operator.

What came to my mind was a simple design of a (Modified SMC by function adding or filter ) to overcome the tremors and of course have the needed robustness and speed BUT again by doing more research I came to another conclusion as below :

In medical field or similar fields they use Minimally invasive surgery (MIS), which is a cost-effective alternative to open surgery, whereby essentially the same operations are performed using specialized instruments designed to enter into the body through several tiny punctures, rather than one large incision. Instead of looking directly at the part of the body being treated, the physician monitors the procedure via a special video camera inserted through one of the small punctures. By eliminating the large incision and extensive dissection,much of the pain of recovery can also be eliminated and the length of hospital stay reduced However, compared to open surgery, MIS is affected by additional physical, visual,

motor, spatial, and force constraints. The MIS tools are constrained by the incision point. The surgeon must coordinate the hand motion that controls the tool,with the remote visual display of the operation being performed by the end-tool. The limited work space and coordination of a pair of tools further compounds the challenge. AND the friction makes it worth so I thought of a friction compensator part which is a system's repeated dynamic part of course modified to compensate the friction. AND again have the needed ROBUSTNESS and SPEED .

Best Regards,

PS: I have attached a simple block diagram of what I said.

One of the advantage incorporating robotics in medical operation is to reduce the hand tremor of the surgeon. In general, I will say there are two types of approaches for doing so. One way is to separate the tremor source, such as using master-slave setup. So the tool is actuated by robot rather than human directly. Examples as the da Vinci Surgical System, and the EYE robot by JHU. 

The other way is to actively detect and compensate the hand tremor of the user. There are a few researches working on actively compensation of the hand tremor during microsurgery, such as retinal surgery. Examples as the hand-held active tremor compensation instrument developed by W.T. Ang, C. N. Riviere, and U.-X. Tan et al. 

Detailed control methodology could be found in their publications. I guess for both cases, the control method depends on the actuation mechanism applied. Hope these info helps. 

Best Regards,

Zhenglong

And, going beyond using robotics only to reduce or eliminate the hand tremors, one might also use robotics in the vision aspect of this equation (surgery, let's say). For example:

http://cdn.intechopen.com/pdfs/36485/InTech-Machine_vision_application_to_automatic_detection_of_living_cells_objects.pdf

You know this is coming, in the not too distant future. More automation in surgery, to go beyond what human doctors might be capable of doing "manually."

Hi, Albert, 

Well, in some application maybe. But I doubt about the concept of automation in surgery... hehe, even now in laparoscopic surgery, surgeons are still arguing if it is necessary to use robots. So far, seems only in some procedures, in urology, it is well received that using surgical robot has superior performance than direct operation with conventional tools.

After all, it is the critical decision making, at least in the near future, artificial intelligence is not capable of replacing human. So automation... is good for those highly repeatable procedures, like those hectic work in industry. But in medical field, it is not impossible, but would take quite a long way to go. That is my personal opinion. 

First, excuse me for my bad english. I suppose you want to reproduce with a robot the trajectory that a human surgeon do by hand. Eliminate the hand tremor is relatively easy by filtering the trajectory during the acquisition, but the filter will introduce a dead time. Depending the bandwidth of the tremor this dead time can be any 1/10 of seconds. Technically, realize the filter is not a big problem. There are a lot of possibilities for designing an efficient filter. We have developed and applyed this kind of filters in our project "Policapture" (video : https://www.youtube.com/watch?v=mH4XxW_1IRY Description in french : http://www.hevs.ch/fr/rad-instituts/institut-systemes-industriels/projets/politrack--systeme-de-programmation-rapide-de-robots-de-polissage-policapture-1797 ).

It's not exactly the same application as yours, but the problem is similar. We have the technology to solve your problem. If you are interested, we are able to develop special algorithms for your application.

Prof. J-D Marcuard, HES-SO Valais, [email protected] 

http://www.hevs.ch/fr/hautes-ecoles/haute-ecole-d-ingenierie/systemes-industriels/

Piet, there are two things I'd like to comment:

First, I don't think the guy is asking for a controller type for this kind of problem. 

Second, PID controller is for linear system control. Well, indeed it is well accepted and implemented by many applications. It requires linearization of the system. But for system that cannot be assume linear at the point of operation, it might not work... that is where other kind of more complex controller comes in. Nevertheless,  PID controller is still the simplest and most effective one to try. 

Control theory is the way to go.