We present a physics-based training simulator for bone machining. Based on experimental studies, the energy required to remove a unit volume of bone is a constant for every particular bone material. We use this physical principle to obtain the forces required to remove bone material with a milling tool rotating at high speed. The rotating blades of the tool are modeled as a set of small cutting elements. The force of interaction between a cutting element and bone is calculated from the energy required to remove a bone chip with an estimated thickness and known material stiffness. The total force acting on the cutter at a particular instant is obtained by integrating the differential forces over all cutting elements engaged. A voxel representation is used to represent the virtual bone and removed chips for calculating forces of machining. We use voxels that carry bone material properties to represent the volumetric haptic body and to apply underlying physical changes during machining. Experimental results of machining samples of a real bone confirm the force model. A real-time haptic implementation of the method in a dental training simulator is described.

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The use of multishaft industrial gas turbines is expanding in various industries because of variation in their structure, flexibility, and their appropriate power generation range. In this study, a semi-simplified black-box dynamic modeling has been done for the three-shaft gas turbine MGT-30. Modeling is done in such a way that all the important variables can be calculated and evaluated. One of the important parameters in dynamic modeling of gas turbine is the time lag relevant to the performance properties of sensors and actuators of the system. In this study, in order to measure the transfer function, physical and actual characteristics of the system were applied. Depending on the type of thermocouples (TCs) used, their activation time was eliminated using a lead compensator. In modeling of the system, the functions were related to the implementation of off-design conditions for compliance with the outputs of a real system model, and outputs were presented proportional to the rate and type of changes for each variable. Finally, validation was done by comparing the power-turbine generated power, exhaust gas temperatures downstream of low pressure (LP) turbine, and speeds of LP and high-pressure (HP) turbines with the real values of Qeshm turbogenerator power plant.

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Here we report a haptic virtual reality simulator for root canal treatment (endodontic procedures). A virtual jaw model was extracted from CT data of a live patient and the volumetric data obtained were visualized using a Marching Cubes algorithm. Collision detection and collision response algorithms were developed using a voxel-based approach. Removal of bone was visualized using a modified real-time Marching Cubes method and deformation of the K-files in the internal surface of tooth canal was simulated haptically and graphically using OpenGL and HDAPI of OpenHaptics Libraries. Using a haptic robot (Omni Phantom) the user can burr the enamel and dentin until reaching the pulp chamber and then the internal surface of a root canal can be cleaned using a simulated K-file.

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Purpose – This paper aims to present the design and implementation of VirSense, a novel six-DOF haptic interface system, with an emphasis on its gravity compensation and fixed-base motors. Design/methodology/approach – In this paper, the design and manufacture of the VirSense robot and its comparison with the existing haptic devices are presented. The kinematic analysis of the robot, design of the components, and manufacturing of the robot are explained as well. Findings – The proposed system is employed to generate a Virtual Sense (VirSense) with fixed-base motors and a spring compensation system for counterbalancing the torques generated by the weight of the links. The fixed bases of the motors reduce the system's effective mass and inertia, which is an important factor in haptic interface systems. A novel cabling system is used to transmit the motor torques to the end-effector. The spring-based gravity compensation system causes more reduction in the effective mass and inertia. Originality/value – This paper provides the details of the VirSense haptic device, its gravity compensation system, and a novel cabling power transmission.