Summary: | 碩士 === 南台科技大學 === 機械工程系 === 99 === As the improvement in medicine, promotes the human life, the world becomes to an aging society gradually, and the demand of wheelchair is also increases. In addition, the long-term use of manual wheelchairs could easily lead to hand injuries, more oxygen consumption and higher heart rate, while the long-term use of electric wheelchair could reduces the cardiopulmonary function due to a lack of hand movement. Therefore, a power-assisted wheelchair with two hub motors as the actuators is proposed, which has the advantages of portability and less operating efforts.
In order to design an easy, convenient, comfortable and safe assisted wheelchair, the hub motors are installed in a manual wheelchair. A digital signal processor DSP2812 is employed as the controller of the proposed wheelchair. The velocity and rotation angle of the two wheels are measured by two rotary encoders, such that the external torques exerted on pushing rims are estimated. The PID controllers are employed to the wheelchair displacement control to provide the appropriate assisted torque. A balance control strategy is employed to overcome the unbalanced torque exerted on two wheels which may cause undesired movement. Finally, the points of limited velocity and wheel response are considered so as to improve the safety and comfort of the user.
|