# An Interventional Surgical Robot Based on Multi-Data Detection
## 3 Experiments and Data Collection  
### Principle and Physical Assembly  
Force detection is particularly important in robotic surgery. In the process of catheter propulsion, especially when the catheter passes through the curve of the blood vessel, the catheter may have friction or collision with the blood vessel wall and produce some resistance. How to detect and judge whether the current resistance is safe is the biggest problem at present. Most robotic systems use a master-slave structure, so the surgeon cannot directly feel the resistance of pushing the catheter from the end during surgery. Conventional force detection method in robotic surgery only relies on force sensors on the clamping module. The force information detected by this method is not accurate. When surgeons are unsure of the current vascular environment, contrast agents are often injected and the DSA system is activated to capture images. If the injection of contrast agent is implemented too many times, it will affect the patient's health and prolong the operation time. Our goal is to establish a force detection method with multidimensional data in light of the current deficiencies of robotic manpower detection in interventional surgery. By fusing the data of multiple sensors and classifying and identifying the data by means of neural network, the bending degree of the current catheter can be judged in real time, and the force information and catheter angle information can be fed back to the surgeon, which can better ensure the safety of the operation. Many insects in the world have tentacles, such as ants, mosquitoes and beetles. They all use their antennae to compensate for a lack of vision or sense of smell. They have many tiny tactile neurons in the head of their antennae that respond to touch [19]. As they move, they can tell if it is safe by constantly touching the ground in front of them with their antennae. As shown in Figure 6, butterflies can sense the changes of the external air flow by using their antennae, and judge whether other creatures are near by the changes of the air flow [20]. Inspired by the function of insect antennae, we regard catheters as insect antennae and install corresponding detection devices in the head of catheters, so that we can make certain judgments about the vascular environment. Some research groups monitored the stress on the catheter by installing strain gauges on the catheter head [21]. However, they only made a vague qualitative judgment on the safety of surgery based on the strain gauge data and could not achieve a more accurate quantitative analysis. On the basis of pasting strain gauge data and combining the data of strain gauge and the force sensor in the traditional clamping mechanism, we used the LSTM network to predict and classify the data series, which can identify the deformation information of the current catheter, so as to give more data feedback to the operator and improve the safety of the operation. A strain gauge is a thin-film device for measuring stress and deformation. It consists of sensitive semiconductor materials arranged in a fixed shape. When the strain gauge is  
Figure 6: The antenna of a butterfly. bent and deformed, its resistance value changes accordingly. Through the construction of the peripheral amplifier circuit, the change of the resistance value of the strain gauge itself can be converted into the change of voltage, and the shape variable of the strain gauge can be known through the voltage. The installation diagram of strain gauge in this paper is shown in Figure 6. The surgical catheter is cylindrical, and the strain gauge needs to be attached flat, so it is difficult to attach the strain gauge directly. The design of the support to paste the strain gauge helps to increase the paste area and ensure that the strain gauge is firm. As shown in Figure 7, two sets of stents (BFH350-6 AA) were installed on the catheter head in horizontal and vertical directions, respectively, and strain gauges were pasted on each stent.