| Summary: | 碩士 === 國立成功大學 === 醫學工程研究所碩博士班 === 94 === Abstract
Powered wheelchairs (PW/Cs) are the major mobility-aided device for persons with moderate/severe physical disabilities, chronic diseases, and the elderly. The PW/C system includes: PMDC motor, open-loop controller, gear box, battery. This research was to design a digital differential speed controller with velocity feedback for improved efficiency and stability of PW/Cs.
The specific aims include：(1) to develop and establish PID speed control on PMDC motor speed model by using Matlab/Simulink software; (2) at flat and inclined surfaces and different speed and loading conditions, investigate the closed-loop and open-loop PMDC motor current and speed responses including transient and stable states also the motor responses for differential speed on left and right motors in the turning; (3) investigate the effect of speed accelerations and decelerations on the closed-loop and open-loop PMDC motor current and speed responses .
The parameter values of Kp =0.5 and Ki =8 and Kd =0.008 are illustrated to be optimal in the PID control on PMDC motor speed, which is agreed to the analytic results. At flat and inclined surfaces and different speed and loading conditions, (1) the PMDC motor shows that the initial current at the open-loop is more rapidly increasing than that of at the closed-loop with PID during the starting state, but more rapidly decreasing during the stopping state; (2) the PMDC motor with PID control shows that the motor speed is not influenced by the different loadings during the starting and stopping states, but the motor current is positively proportional to the loading. Atthe
acceleration and deceleration conditions, the PMDC motor with PID control has demonstrated the same current and speed responses resulted from the starting and stopping states. At the turning conditions, (1) the open-loop control shows that the differential speed of right and left motors is increasing with the PW/C speed, but is decreasing with the increase of external loading; (2) the PID closed-loop control sows that the differential speed of right and left motors is not influenced by the external loading. Therefore, the PID parameter with Kp =0.5 and Ki =8 and Kd =0.008 has demonstrated to be useful in the improved design of closed-loop controller for the efficiency and stability of the PW/C.
The future works are recommended to conduct field testing of the controller on PW/Cs and to investigate other control methods such as adaptive and variable structure control.
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