Simulating mechanical properties of human tissues or organs based on magnetorheological fluid for tactile display

Robot-assisted minimally invasive surgery enables surgeons to tele-perform elaborate surgical operations to patients with less damage and pain. Besides force feedback provided by the surgical robot to the surgeon, touching sensations are also important for the surgeon to acquire the complete conditions of the patient. Thus, tactile display devices are crucial elements in surgical robots. Meanwhile, various sensations of magnetorheological (MR) fluid can be provided to human fingers because its stiffness, elasticity, and viscosity can be controlled by applied magnetic field. Therefore, in this paper, a new tactile display device based on MR fluid is proposed. This device has high magnetic conduction efficiency, less magnetic leakage, no MR fluid leakage, and overcomes the major drawbacks of the existing tactile display devices based on MR fluid in literatures. Firstly, the design of the tactile display device is described in detail, followed by its fabrication and assembling methods. Secondly, the working current range of the tactile display device is determined by using electromagnetic finite element method (FEM) simulation. Thirdly, the mathematical model to characterize the compression and shear behaviors of the tactile display device is developed. Then, the tactile display device is tested in terms of normal and shear contact forces, followed by its elastic and shear moduli analysis. Finally, the unknown parameters in the mathematical model are figured out, and the model is validated by using structural FEM simulation. The experimental results show that the elastic and shear modulus range of the proposed tactile display device are respectively 3-7.5 kPa and 1.4-5.0 kPa, which can cover the mechanical properties of various human viscera.

Automated summary

Robot-assisted minimally invasive surgery allows surgeons to perform complex surgical operations with less damage and pain. A new tactile display device based on MR fluid is proposed, which overcomes the major drawbacks of existing devices and provides various sensations to human fingers.