Based On Two-way Pneumatic Muscle Force Feedback Data Gloves

In virtual reality system, force simulation and display is a basic method to strengthen the realistic sensation and construct the immersion. The research about it has received increasing attention, and become an appealing research field. At present, there are different ways to realize force feedback, one of which widely used is force feedback dataglove.A novel bi-directional force feedback exoskeleton dataglove using pneumatic muscles as actuators is presented. The dataglove exerts bi-directional force only on the fingertip, not on every finger joint. Thus it has advantages of simple structure, light weight, firmly attached itself to the finger, and is easy to be control. The dataglove can supply bi-directional force to drive the finger to flex and extend in bi-direction, which make it not only applied to virtual assembly system and telepresence system and other virtual reality fields, but also applied to rehabilitation of finger injuries.Firstly, the overall structure, actuation system, principle of angle measurement and principle of force feedback are introduced. The combination of a pair of antagonistic pneumatic muscles and brakes is applied to actuation system, which not only meets the need of the natural motion of hand, but also brakes the pneumatic muscles whenever it is necessary to generate bi-directional force feedback. The flexion angles of lingers are indirectly measured by the non-contact magnetoresistance sensors. A torque sensor based on strain measurement has been developed to indirectly measure fingertip force by measuring the driving torque of the dataglove.Based on the simplified hand model, the kinematic analysis and static analysis of index finger and the dataglove are made. The fingertip force and the kinematic relation between finger joints and the leverage of the exoskeleton are derived, which provides theoretical basis for the structural design, angle measurement and force feedback control of the dataglove. According to the kinematic analysis and static analysis, the working principle of the dataglove in the virtual reality field and the rehabilitation of finger injuries is studied, which lay a theoretical foundation for the application of bi-directional foce feedback dataglove.Secondly, the measurement theory, error correction method, angle conversion and reference point determination of the angle sensor are introduced. The measurement theory and the calibration method of the torque sensor are presented. On the premise of meeting wearable requirement of the hand, the effects of structural parameters of linkages on angle measurement and fingertip force are analyzed, which provides help for the choice of parameters.Finally, an experimental system of the force feedback dataglove is established. The experimental control program is compiled by Labview, which could acquire angle signal and force signal. The basic characteristics testing of the self made pneumatic muscle is done, and the experiment of angle measurement is finished. Experiments about static and dynamic characteristics of the dataglove are researched. Based on the above experiments, fingertip force feedback closed-loop experiments with PID controller are studied. Experimental results indicate that the dataglove designed in this paper can measure the flexion angles of finger joints, and supply realistic bi-directional force effectively.