Integration of microsensor for microsurgery robot’s end-effector

Abstract

of the instrument-tissue contact state, and an ability to predict the outcome of manipulative actions are required [1].Keratoplasty (corneal grafting) is an elaborate and difficult ophthalmic microsurgery that requires minute cutting force and depth. Our research aims at the development of robotic microsurgical system for lamellar keratoplasty. Force and position microsenors are integrated on robotic end-effector. Robotic trephination can be executed precisely, with the control of punching force and cutting depth. Sensor integration requirementsAs the therapy for the second most common disease in ophthalmology-corneal disease, keratoplasty is an ophthalmic microsurgery that has been performed extensively nowadays. Two primary parts of the surgical procedure are trephination and suture. The operational instruments are usually trephine and needle for ophthalmic microsurgery. There are two types of corneal grafting according to the cutting depth: penetrating keratoplasty and lamellar keratoplasty. To decrease the postoperative astigmatism and complication, the microsurgical robot is developed to replace some manipulations done by the surgeon's hand before. The punching performance (trephination) of robot should achieve the following results: the position of grafting button and bed should be precise (the distance from the center to the corneal limbus center is less than 0.5mm), the shape of the button and bed is regular, the cutting depths are identical, and the edge is perpendicular and smooth.The mechanical structure of robot consists of the robotic arm and end-effector trephine. The robotic arm can adjust the position and orientation of the end-effector trephine.The characteristics of the end-effector trephine are as follows.1) The operational space for ophthalmic microsurgery is small and close-packed. The distance between the object lens of surgical microscope and the eyeball of patient is about 160 mm, and the operational region is about 30 mmx15 mm. Therefore, the normal volume of end-effector trephine should be smaller than 30 mmx30 mmx50 mm.Abstract To enhance the effect of robotic microsurgery, the microsensors are integrated on the robot's end-effector. On the basis of the requirements presented for the integration design, measuring mechanism for the robotic end trephine's force and cutting depth are studied. Force microsensor and position microsensor are used to measure surgical information of the force and depth. Measuring mechanism was achieved by means of linear sliding bearing and differential measuring structure. The sensor data board was developed. With the power spectral estimation of sensor data, two digital filtering methods are proposed, to help eliminate the interference to the original microsensor signal. They are the filtering method of lowpass-bandstop serial structure suitable for a PC, and a shift average filtering algorithm suitable for the sensor data board, respectively. The experimental results show that the integration of microsensors for microsurgery robot's end-effector can satisfy ...

An evaluation on the operation parameters of trephine cutting cornea based on biomechanical response

“…In many surgeries, the robots can assist the surgeons in undertaking some tasks, such as suturing and cutting, it is required that a smart control, a force-sensing of the contact between instrument and tissue, and an ability to predict the outcome of operations [6]. An experimental system for robotic trephination has been designed, which comprise a surgical robot, a trephine manipulator, a dataprocessing system, and a control system, as shown in Fig.2.…”

“…Evaluating the operation may provide insight into the contribution of trephination methods to decrease the likelihood of complications arising. A few researchers are exploring advanced techniques to achieve good trephine results, such as femtosecond laser technology, robotics, and so on [6,7]. The use of femtosecond laser has some advantages, and it can prepare different configurations with a smooth cutting margin and a precise depth, but there are some drawbacks in clinical surgery, for example diseased cornea may affect laser energy, and the applications may be limited due to negative pressure suction in trephination.…”

“…Robotics, the most similar method of manual operation, may overcome some shortcomings of manual operation, but the main application limitation is to ensure the reliability of micromanipulation in clinical microsurgery. Hu et al [6] designed a robotic manipulator for trephine cutting cornea, and one of micro motors drove the trephine to punch the cornea linearly, and the other could realize the rotary motion based on the gear transmission. The mechanism is ingenious, but it did not consider the rotation angle can be adjusted.…”

Design and research of a robotic system for ultrasonic‐assisted lamellar keratoplasty

“…Therefore, an ultrasonic-assisted lamellar keratoplasty robotic system has been developed based on the former research [6][7][8], which was designed to realise the high-precision automatic control of the corneal cutting depth.…”

“…Robots have the advantages of stability and high precision. Some research works on robot‐assisted trephination [6], suturing and knotting [7] have been done by the research team at the Beijing University of Aeronautics and Astronautics, which aim to overcome the limitations of manual operation.…”