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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 ...

The robotic system is developed to improve the effect of microsurgery for keratoplasty. The autonomous suturing should be qualified for the operational requirements of microsurgical keratoplasty. Poorly modeled mechanism of robotic micromanipulator and slight movements of surgical objective point are hindrance for precise position and orientation of end-needle. Visual servo control is available to overcome these obstacles. An appropriate scheme of robotic vision is proposed. On the basis of biological binocular vision, a feasible method of calibration and reconstruction for surgical microscope is adopted. The model parameters estimated by linear regression are evaluated for accuracy, stability and robustness. The visual servo control is applied for guiding robotic end-needle to reach the penetrating objective point. The visual servo control has lookand-move architecture based on image feature. The experimental results show that the robotic system for microsurgical keratoplasty can fulfill the surgical task of suturing penetration precisely.

Torque motor is a kind of special motor with a large number of poles, which can continue to operate at low speed or even when the rotor cannot rotate (that is, the rotor cannot rotate) without causing damage to the motor. In most cases, in order to meet the needs of industrial production and life, we need to torque motor for high-precision torque control. In this paper, we applied the expert PID control method to torque control. MATLAB simulation and experimental results show that the expert PID control has achieved good results in torque control of torque motor.

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