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

Abstract

Prostate cancer has one of the highest incidences of male malignant tumors worldwide. Its treatment involves the robotic implantation of radioactive seeds in the perineum, a safe and effective procedure for early, low-risk prostate cancer. In order to ensure precise positioning, the seed implantation needle is set at low terminal velocity. In this paper, the motion output position instability caused by the friction torque of the robot’s motor and rotating joint during low velocity motion was analyzed and studied. This paper also presents a compensation control method based on the LuGre friction model, which offers piecewise parameter identification with GA-PSO. First, based on an analysis of its structure and working principle, the friction torque model of the robotic system and the torque model of the driving motor are established, and the influence of friction torque on motion stability analyzed. Then, based on experimental data of the relationship between velocity and friction torque for no-friction compensation, the velocity point of the minimum torque of the rotating joint and the critical Stribeck velocity point were used for segmental parameter identification; cubic spline interpolation was used for segmental fitting. Furthermore, on the basis of the LuGre model identification method, parameter identification of the genetic algorithm-particle swarm optimization, and compensation control of the LuGre friction model, a control method is analysed and set forth. Malab2017a/Simulink simulation software was used to simulate and analyze the control method, and verify its feasibility. Finally, the cantilever prostate seed implantation robot system was tested to verify the effectiveness of the segmented identification method and the compensation control strategy. The results reveal that motion output position stability at low velocity meets the requirements of the cantilever prostate seed implantation robot, thus providing a vital reference for further research.

Modeling and Analysis of Prostate Soft Tissue Puncture Performance using Puncture Needle

“…The confidence of Equation ( 20) reaches 98%, R-square: 0.9879 (∼1), and as shown in Figure 8(b), the connecting line (red line) of the data is consistent with the discrete data points. Therefore, this study uses the improved adaptive particle swarm algorithm [11,32] to solve the minimum value of Equation (20), and the optimal puncture speed is obtained as 12.60 mm/s. To verify the effectiveness of the obtained optimal puncture speed (12.60 mm/s) in this experiment, it (12.60 mm/s) was compared with 10, 11, 12, 13, 14, and 15 mm/s, as shown in Figure 9.…”

“…US)) is a representative medical robot, which not only possesses a high positioning accuracy and good motion stability but also can continuously replace the work of doctors. This robot causes minimal trauma to patients and facilitates postoperative recovery [11,12]. Minimally invasive interventional surgical robot technology is used to treat prostate cancer by implanting radioactive seeds such as I 235 and I 125 .…”

A Novel Non-Isotonic Statistical Bivariate Regression Method—Application to Stratigraphic Data Modeling and Interpolation

“…Although the monotonization/demonotonization stages are independent of the monotonic regression algorithm sandwiched inbetween, hence, in principle, every regression algorithm might be invoked, our aim is to make use only of computationally simple (rather elementary) numerical operations, which are incompatible with complex methods such as kernel-based smoothers (see, e.g., [23]), neural networks (see, e.g., [24]) or splines-based regressors (see, for example, [25]).…”

Study on the Control Method and Optimization Experiment of Prostate Soft Tissue Puncture

“…According to statistics, prostate cancer is second only to lung cancer among male patients [3]- [6], and the incidence in China and other Asian countries are also increasing and tending to be younger [7]- [13]. At present, the treatment of prostate cancer mainly uses the minimally invasive surgical method of radioactive seed implantation, and the traditional surgery is mainly performed by doctors manually or using robots to complete related operations [14]. However, due to the uncertainty of the doctor's operation, it is not only difficult to guarantee the positioning accuracy, but also causes severe trauma to the soft tissues, thereby affecting the treatment effect [15], [16].…”

“…It has four operating arms attached to a rotating bracket that can move towards any part of the patient's body, and an endoscope that can be attached to any operating arm. In addition, it has a small robotic arm that can reduce collisions between them and offers a wider range of motion, mainly used to assist doctors in precise and complex minimally invasive surgery [14].…”