Force Feedback Device For Sensing Stiffness Of Virtual Objects

In the development of computer virtual reality technology,the simulation and interaction technology of virtual 3D environment is a research hotspot.In the simulation and interaction of virtual environment,force feedback system provides the input and output of force sense.Therefore,force feedback is introduced into the simulation of interactive virtual environment as a new human-computer interaction technology.With the help of force-sensing interactive devices,people can measure the simulated state of forces and sense the size,shape and motion of objects.At present,most of the force feedback devices on the market have low flexibility,high cost and low penetration rate,so the research of new force feedback devices with high precision and cost-effective is of great significance.A new hand-held device,VRTweezer virtual tweezers,is designed in this paper,which can be used to sense virtual objects.It simplifies the user’s action of taking an object as the interaction of the thumb,index finger and middle finger with the virtual object.It can simulate the thumb and index finger to pinch an object and the three fingers to pinch a thin sheet and a rod.To capture the Hand’s pose for the next step of collision detection,this paper innovatively uses the rotary encoder to capture the angle between the thumb and forefinger,using ultrasonic distance measurement to capture the relative position of thumb to capture the gesture of hand.In order to provide the feedback force between the thumb and forefinger,the computer uses the finite element analysis method to calculate the impact force and resistance force on the fingertip according to the depth of the virtual finger pressed into the virtual object.The contact instant simulates the impact force between the two fingers by controlling the speed of the servo motor of the thumb and forefinger To grasp the object continuously,we can simulate the resistance of the thumb and forefinger to pinch the flexible body by inserting the torsion spring ratchet and the cross-layer friction of the screw steering machine.In order to render objects of different sizes,rigidities and shapes more realistically,this paper conducts user perception research to evaluate the performance of the device,and designed two user survey examples-chess and fruit picking.Users can perceive objects more realistically using our devices than using virtual tools for vibration feedback.