Drive and control system of electric medical bed based on Cortex-M3

LU Xiao-jian1，LI Qiang2，DING Miao-jiang1
（1. Zhejiang Jiecang Linear Actuator Technology Co. Ltd.， Xinchang 312500， China；
2. Hangzhou Dianzi University Institute of Computer， Hangzhou 310018， China）

Abstract： In order to solve the problems of simple function and backward technology of domestic electric medical bed，a drive and control system of electric medical bed which could drive multiple linear actuators synchronously to realize complicated functions of position control was presented. The Cortex-M3 was used as its core，and the closed-loop control circuit was constructed with dual Hall sensors in actuators， the synchronization motion control for multiple linear actuators was realized by using fuzzy PID algorithm. The CASS embedded platform was used to program with ladder diagram to implement control logic on the special controller，which improved the programming efficiency. The system's structure，the improvements of mechanical structures in linear actuators and the design of the controller were described in detail. The system has been used in an ICU medical bed which is driven synchronously by three column actuators and two handhold actuators. The results show that this system realizes all kinds of care and rehabilitation functions.
Key words： electric medical bed；linear actuator；synchronization motion control；graphical programming