Development Of Walking Speed Control System For CIP-I Intelligent Artificial Leg

Intelligent artificial leg has been an interesting research project in the fields of robotics, biomedical engineering, and rehabilitation engineering. It incorporates many important subjects, such as information technology, computer technology, artificial intelligence, automatic control, sensor technology, mechanism design and manufacture technology, new material technology, and so on. Compared with a conventional artificial leg, an intelligent artificial leg has a better performance. It can imitate the function of healthy leg more accurately, the gait of an intelligent artificial leg is more natural, and the leg-amputee can save more sinew. Without the human intervention, an intelligent artificial leg can imitate the motion way of healthy leg independently, so the leg-amputee's attentiveness can be released from the artificial leg, and then the walk of the amputee becomes a subconscious behavior. The significance of this research is that it can improve the leg-amputees' living condition and promote the development of Chinese medical welfare.This thesis deals with the design of CIP-I Leg's walking speed control system. First, the working principle of CIP-I Leg is introduced, and then the design scheme of the walking speed control system is discussed and determined. A stepping motor was used as the actuator in the system and closed-loop control method is adopted. Because there are many nonlinear factors in the system, such as reverse backlash, dead zone, friction, saturation, the fuzzy sliding mode control method was employed to overcome these nonlinear factors. The mathematical model of the controlled plant was developed and the control algorithm was simulated in the compute. The results indicated that chattering of the system was avoided as the fuzzy control was introduced into sliding mode control, and the control effect was very good.In the following parts of this thesis, the design method of the system is presented in detail from the aspects of both hardware and software. In hardware, the system includes the motor drive circuit, motor speed measurement circuit, blade position detection circuit, walking speed measurement circuit, communication interface circuit, power supply circuit, and so on. Considering the limitation of the hardware installation space and battery's capacity, we tried our best to make the whole circuit structure as simple as possible and decrease the system's power consumption when designing the hardware system. Software designs include the designs of main routine and interrupt service routines. The software design method of every function module is presented in detail. In order to be convenient to maintenance and upgrade, C language was adopted in the software development.The intelligent artificial leg walking speed control system designed in the research has many good features such as low costs, low power consumption, high control precision and reliability, rapid response speed, strong anti-jamming capability, and high stability. The expected design goal was achieved.