Dummy emulation system force feedback computation method

Abstract

The invention discloses a calculation method for force feedback in a virtual system, which comprises the following steps: step 1: a virtual environment comprising a virtual space, a virtual object and a virtual tool is established, attributes of the virtual tool are set, and a point set model which includes a plurality of mass points and surrounds the virtual tool is constructed; step 2: the virtual tool and a force feedback device are bound, the motion states of the virtual tool and the virtual object in the virtual space are tracked, whether the virtual tool and the virtual object collide or not is judged, if yes, step 3 is implemented; the step 3: the line speeds and the motion speeds before and after the collision of all the collision mass points of the virtual tool during the collision are respectively calculated, and the received impact during the collision process is also calculated; step 4: the resultant forces and the resultant moments of forces of all the collision mass points of the virtual tool are calculated and sent to the force feedback device. The calculation method takes full account of the self-rotation features of a virtual surgical instrument and can be applied in a surface model or a body model adopted in the virtual surgery.

Description

A Calculation Method of Force Feedback in Virtual Simulation System technical field The present invention relates to the field of virtual simulation technology, in particular, in a virtual simulation system, for a virtual tool with rotation characteristics, the calculation method of force feedback can be widely used in medical technology, for example, it can be implemented in a virtual surgery simulation system Calculation of force feedback. Background technique Virtual simulation technology has been widely used, especially in the medical field. For example, virtual surgery is a virtual reality simulation application system specially used to simulate various phenomena that may be encountered during surgery. Through virtual surgery, the operator can be immersed in the virtual surgical scene, experience and learn how to perform various operations by manipulating virtual surgical instruments. On the one hand, it can help interns learn and master the anatomical structure of ...

AI Technical Summary

Problems solved by technology

In the stage of force rendering, Morris calculates all the voxels immersed in the virtual surgical instrument when contacting the bone through the virtual surgical instrument, and calculates the distance from each voxel to the center point of the circular tool by ray tracing method. The contribution of each voxel to the force of the virtual surgical instrument is obtained, but there are still some problems in this method, because the calculation of all contact forces is based on the vector of the voxel inside the virtual surgical instrument rather than the geometric information on the surface of the bone model. , so it is easy to cause force oscillation and discontinuity during force rendering

In 2006, Eric et al. (EricA, AlanL.Real-timeVolumetricHapticandVisual BurrholeSimulation[C], 2007IEEEVirtualRealityConference, 2007: 247-250) proposed the method of using voxmappoint-shell to simulate the interaction between virtual surgical instruments and bones, reducing the inconsistency of force. Continuous, but since this method is also based on the normal vector of the tool surface when calculating the direction of the force, it is not conducive to expressing the real force direction felt by the virtual surgical instrument when the virtual surgical instrument interacts with the bone

(1) There is a lack of consideration of the motion characteristics of the virtual surgical instrument itself. The high-speed rotation of the virtual surgical instrument is very critical to the real and effective simulation of the feedback force generated by the bone drill or the bone grinder when removing the bone.

(2) Using methods based on volume rendering or surface rendering to simulate the generation of force feedback in bone surgery requires the calculation of force feedback for a large number of discrete voxel data, which is likely to cause force oscillation and discontinuity

Therefore, there is currently no method for calculating force-sense interaction and force-feedback systematically for virtual tools with their own rotation characteristics.

Especially for virtual surgical instruments, such as bone drills and bone grinders, the physical characteristics of the most commonly used tools in orthopedic surgery and bone plastic surgery, such as shape and rotation, have not been specially designed and established for a force-sensing interaction model

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