Design And Implementation Of Intelligent Wheelchair Based On Speech And Head Posture Control

With the increasing of the number of elderly people, patients with chronic diseases and accidental injury in China, the risk of disability we faced are continuously increasing, and more and more people lose their ability to walk which produces huge burden to their families and the society. In order to improve the life quality of people who is inconvenient inaction, the intelligent wheelchair is gradually valued and supported by people from all walks of life. With the increasing of demand for wheelchair and the strengthening of cooperation between manufactures and research institutions, the development of intelligent wheelchair is becoming more humanized, more comfortable and safety.In this thesis, an intelligent wheelchair with multiple operating modes method is designed based on the speech and head posture recognition technology. The fuzzy logic control algorithm is adopted to solve the problem of automatic obstacle avoidance in the process of local path planning. This thesis introduces the structure design and implementation of the intelligent wheelchair system, which is divided into five modules: ranging module, human-machine interface module, positioning module, motor control module and the master module. In these modules, the thesis puts emphasis on the human-machine interface module and the mater module.In the human-machine interface module, the thesis describes the design and realization of the intelligent wheelchair about speech control and head posture control in more detail. The speech control module can synthesize, recognize the speech by using Android application software, and interact with the intelligent wheelchair through Bluetooth. The head posture control module collects head movement data from the three-axis acceleration sensor, analyzes the time-domain characteristics of the data, identifies the head posture by using threshold method and communicates with the intelligent wheelchair by Bluetooth module.In the master module, the thesis introduces the principle of the environmental perception and self-positioning for intelligent wheelchair, and the fuzzy logic control algorithm is applied to the local path planning, which can solve the problem of automatic obstacle avoidance well in a relatively complex environment. The function of environmental perception is achieved by establishing the environmental information around the wheelchair in the master module that obtains the distance information from the ultrasonic ranging module. The intelligent wheelchair mainly uses photoelectric encoder to realize self-positioning. The positioning module collects data from the encoders installed in the motor shafts on both sides of the wheelchair, analyzes and uploads them to the master module. The master module gets the data, computes the position and orientation of every moment of the wheelchair based on the principle of dead reckoning, and finally implements the function of positioning.Now each module of the intelligent wheelchair system has been tested, and the results show that it meets the requirement of reliable operation. The effectiveness of the path planning method has been verified by simulation experiments and preliminary tests in an indoor environment.