F2T Force Feedback Tablet

We proposed a haptic surface device based on the principle of force-feedback, named F2T (Force Feedback Tablet) to create the possibility to experience a 2D space environment through touch. The force feedback principle follows the principle of interaction with the user allowing a better comprehension of image contents. The F2T device consists of a small thumbstick mounted on an actuated support. The thumbstick acquires the user’s movement intentions, and the actuated support generates haptic effects by moving the thumbstick under user’s finger.

Several Functioning Modes

This architecture allows a wide range of haptic and interactive effects to represent the content of an environment:

- Passive feedback, by slowing down or stopping the finger’s movement. This effect allows to represent different kind of frictions: fluid friction when the speed reduction is proportional to the intended speed, and solid friction when the reduction is constant. These effects are used to help discriminating areas and textures. The height variations and edges, are simulated by accelerating or slowing down or stopping movement according to the slope. It is possible to prevent the access to certain parts of the tablet in order to be able to follow the contour of objects to help integrating object’s shape.

Red colored parts encode fluid friction.

Blue colored parts encode solid friction.

Green colored parts encode the variations of height and edges

- Interactive and dynamic effects, such as flows and attractive / repellent force fields, to represent a dynamic and interactive environment(water flow or wind) or to aid user exploration.

Use of active effects: flows.

Another active effect: the rails. The finger is deflected towards a given direction.

- Guidance mode, where the F2T guides user’s finger on a predefined path without considering user’s intention, allowing a guided exploration of the surface content. The efficiency and resulting perception of space using F2T’s haptic effects are outlined through tests on spatial comprehension.