Study on the Low Velocity Stability of a Prostate Seed Implantation Robot’s Rotatory Joint

Round 1

Reviewer 1 Report

Happy with all the answers provided and the modification made.

Reviewer 2 Report

Very good paper. Congratulations

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The paper proposes a new method for the control of a prostate implant robot which will minimize improper implantation of radioactive particles and tissue trauma. The paper has valuable elements and will be of interest to a relative large audience. However, ultimately, I feel there are minor limitations within the work which I will to attempt to sumarize below.

 

1.- Moderate revision for English.

2.- Figures 8 and 9 have low quality and do not help to understand.

 

 

Reviewer 2 Report

1) Most if not all urological surgeries in North America have been done with the Da Vinci robot. The authors should contrast (kinematically) their manipulator to the Da Vinci.

2) Equation 5 should include the loading due to insertion of the needles.

3) The first six equations along with figure 2 is textbook material. No information is given regarding gear transmission vs. direct drive. If the electromechanical time constant is much larger than the electrical time constant the model of figure 2 can be significantly simplified.

4) The nonlinear friction model renders the whole motor model to be piecewise linear . No attempt by the authors to study real and virtual equilibrium states, following Kalman’s paper.

5) The notation of equations 7-10 is odd mixing time domain with Laplace transform

6) Equations 11-14 imply a superposition sum, which is most likely invalid due to the non linearity of the model. I also question the existence of the sinusoidal input.

7) I am not familiar with the LuGre Model. The accelerated time frame for the review prevented me from studying references 26-28. Sorry.

8) The experiments imply step angle command in an open loop position servo. That’s why the output angle follows a ramp signal. Shouldn’t the authors have used closed loop servo?

Reviewer 3 Report

An interesting study with both simulation and experiment results. In general, well structured and presented paper.

At the begining, the modelling of a brushless DC motor is not necessary introduced in detail as it has been well established. No new contribution was presented. 

The used prostate implant robot should also be introduced in more details.

In thesimulation results, i.e. Figure 8 and 9, there were lags for both PID and LuGre model control in the first 2-3 seconds. What could be the reason? Is it due to the dead zone from the motor? 

In the expeirment results, the input speed is as low as 0.001/s. Is it realistic in the operation? What is the normal required speed during operatoin? In both Figure 11 and 12, labels should be inserted for line 1-4.