The communication mode that seems most relevant for manipulating physical objects is hand motion.People use this mode to act on the world,to grasp and explore objects,and to express ideas.It is hoped that by using haptic interfaces other than traditional devices such as keyboard and mice,the user could manipulate the virtual objects directly in a free form.Just like they perform most everyday tasks dexterity and naturally with hands. The CAS.Glove has been developed for the virtual environments as a gesture input device.It is mounted sixteen our patented flexible sensors that is linear and reliable. With improved circuits and optimized layout of flexible sensors,CAS-Glove could measure the position and movement Of the fingers and wrist accurately.To increase the resolution and reduce the noise,oversampling and digital filtering techniques are applied to a DSP.based data acquisition system.A novel four.finger calibration method is presented for high.precision joint-sensing. The haptic feedback modality groups tactile feedback and force feedback.Tactile feedback could significantly enhance touch perception for virtual environment applications with minimal design complexity and cost.In order to create realistic tactile feedback.we developed two kinds Of tactile interfaces.One is mounted five vibro-tactile actuators on each fingertip.it could provide the user with sense of tapping,contacting and vibrating.Another is based on vibrating voice coil with high bandwidth.it could produce much more complex contact surface information associated with tactile feedback. A new kind of point type force feedback interface named PEDFinger has been developed.Generally.it is used with a data-glove as a force.sensing glove.An improved proportional electromagnet is used as the actuator of this device.Force is transmitted from actuator to effector via steel cable.spring pipe.With a compact and adjustable structure.it could be fixed on almost every user's fingers.A fuzzy plus integral controller is applied to the force control.Two versions Of PEDFinger.the PC.based system and the DSP-based system have been developed.Both of them could provide a high performance and low cost solution for the VR application. A more efficient force feedback interface called ForceFeel has been developed.It could actively prevent operator's fingers from moving into a restricted simulation space.A single neuron adaptive PID contr01 algorithm was implemented for the robust control 0f this time.varying and nonlinear system.The forces exerted on the user's fingers by it could maximize the sense of immersion in a virtual environment. The orientation relative to an Earth.fixed reference frame of limb segment is determined through the use of an attached MAB sensor.A quaternion-based complementary filter algorithm is implemented for processing the output data from three orthogonal magnetometers and three orthogonal linear accelerometers to determine the
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