Research And Design Of ARM-Based Embedded Hand Hold Control System Of Intelligent Artifical Leg

Intelligent artificial leg is a new kind of leg prosthesis with highquality, which developed in 1990s. Compared with the traditional legprotheses, it is more bionic in structure and function, and its parameterscan be regulated automatically to guarantee that it works stably and hasflexible performance according to changing environment and workingrequirements. The significance of this research is that it can helpamputees to return to the mainstream society and lighten the burden ofthe society and their families.The control system of intelligent artificial leg is made up of twoparts, hand hold control system and controller in leg. The swing of anintelligent artificial leg is produced by the movement of the piston of thepneumatics cylinder, which is mounted in the leg. The motor located atthe tail of the pneumatics cylinder is used to control the opening of aneedle valve in the cylinder. The controller in leg whose functionalparameters are set by the hand hold controller controls the needle valueby controlling the motor. Through changing the opening of the valve, thebending and extension speed of the knee joint of the leg can be adjusted,so a suitable walking speed can be obtained. The intelligent artificial legsproduced several years ago have some shortages. For example, one is thatmicroprocessors used in hand hold controller are mainly 8 bit single chip,which cannot meet the requirement of the system because of their lowerrunning speed and higher power consumption. Furthermore, the datatransmission mode between hand hold controller and controller in leg isserial communication, which is not convenient for operations and maybring some trouble in running. Finally, the control systems of artificiallegs, which are used to control the opening of the needle valve ofpneumatic cylinder, usually are an open-loop system with a steppingmotor. This kind of control system has lower position precision and nointelligent behavior.Aimed at the above-mentioned shortages, following improvementswere made in this research. First, we adopt ARM7TDMI Structure-Basedmicroprocessor S3C44B0X of Samsung as the central processing unit of hand hold controller, which is helpful to reduce the volume and powerconsumption of hand hold control system. Then, the chip S3C44B0Xembedded with real-time operation systemμCLinux and some applicationprograms could ensure the hand hold controller run more stably andpossess excellent expansibility. Thirdly, we use Infrared Data Associationas the wireless communication way instead of the serial communication,which can reduce the steps of operation and ensure it work more reliably.In addition, a servo DC motor is used to replace the stepping motor, and athree close-loop control scheme with position, speed, and currentfeedbacks is designed for controlling the opening of the needle valve.In this thesis, our research mainly deals with the design of anew-style embedded hand hold controller in accordance with CIP-I Legclose-loop control scheme. Through experiments, the results reveal thatthe hand hold controller we designed has high reliability, low powerconsumption and excellent expansibility, so the research may have greatpractical value.