Shin Usuda

Telerobotic-assisted bone-drilling system using bilateral control with feed operation scaling and cutting force scaling

Drilling is used in the medical field, especially in oral surgery and orthopaedics. In recent years, oral surgery involving dental implants has become more common. However, the risky drilling process causes serious accidents. To prevent these accidents, supporting systems such as robotic drilling systems are required.

Modeling and experimentation of drilling vibration for implant cutting force presenting system

Since uncontrolled force can cause drill-bit break-age, excessive heat generation, and bone damage, prediction of the drilling force is important parts to increase success rate of implant operations. This paper presents a vibration model for prediction of the drilling vibration. The force from the drill is modeled by considering variation in force caused by CT value and feed velocity change. This method can be applied for a cutting force presentation method using haptic drilling system. This system allows dental students to learn procedures such as cutting the jaw bone. It can also be used for prior confirmation before implant surgery because doctor can experience the force response. The advantages of this system are the high force output quality and fine position sensing quality. The validity of the proposed method was confirmed through experiments using pine wood mentioned in Mischs bone density classification.

Real-time CT value estimation method for robotic drilling system based on thrust force and torque

An estimation of bone density is important for dental implant. CT value has been used in clinical and diagnostic as a quantitative evaluation method of bone density. In this paper, a method for estimating the CT value is proposed by modeling the relation between the cutting force and the CT value. The cutting force is calculated by the thrust force of the linear motor and the torque of the rotary motor. The estimated CT value can be obtained in real time by comparing between the force from reaction force observer and the formula of CT value with the pre-estimated parameters. The validity of the proposal was confirmed through experiments using wood mentioned in Mischs bone density classification. The experimental results indicated that the error of CT value estimation was ±91 HU and the estimation accuracy was 84 %.

Modulated potential field for position adjusting with human interaction for implant surgery

Image processing and robotics are leading technologies to improve dental surgery. The important information for physicians to perform implant surgery is “where to start cutting” and “when to stop cutting”. The aim of this research is to achieve automatic guide system for teaching the information of “where to start cutting”. To achieve this aim, L-J potential field, which can realize required performance of position adjustment with human interaction are proposed in this paper. Proposed potential field has three features. First, physician can free moving the manipulator when far from the distinction. Second, the manipulator will apply adjusting force for correctly converges to the destination when approaching to the distinction. Third, the manipulator will apply adjusting force for collision avoidance when passing the distinction. The validity of proposed L-J potential are confirmed through experiment using 2DOF parallel link manipulator.

Stereo vision based robot navigation system using modulated potential field for implant surgery

Image navigation systems and robotics are leading technologies to improve the accuracy of dental surgery. In this paper, stereo vision based navigation system is implemented to the three degrees of freedom implant surgery assistant robot. The aim of this research is to achieve cooperative guide system for teaching the information of “where to start cutting”. To achieve this aim, modulated potential field based on Lennard-Jones potential field is proposed for realizing following three requested performances. (1) Surgeon can freely operate the manipulator when it far from the destination. (2) The manipulator will apply adjusting force to converge correctly when approaching to the destination. (3) The manipulator will apply adjusting force for collision avoidance when passing the destination. This paper uses stereo camera to detect the destination. The validity of the proposed method is confirmed through experiment using three degrees of freedom parallel link manipulator.