Control Of Hydraulic Drive System Of Underwater Exoskeleton Robot

As technology advances, wearable robots has played an increasingly important role in improving human’s efficiency, enhancing human’s exercise capacity and helping patients regain health. Underwater robot researched in this paper is a typical application wearable power assist robot. Diver’s diving speed and distance underwater are limited by physical fitness. As a result, it is difficult to complete the arduous task underwater. However, underwater robots help enhance the user to boost athletic ability. Reasonable power source is a prerequisite for the underwater robot for work. At present, the main robot drive systems are hydraulic drive, pneumatic drive and motor. Hydraulic drive system with advantages of compact structure, good tightness and adequate power is the best choice for underwater robot drive.Research on control method for the hydraulic drive system is the main content of this paper. Firstly, three basic equations are derived by analyzing the mechanism of the mechanism of hydraulic system. In addition, control object model is built by integrating basic equations and related transfer functions of control system. Secondly, PID control algorithm based on disturbance observer is designed for hydraulic control system. It suppresses the interference parameter fluctuations and load power fluctuations effectively when improving the response performance of the system. Thirdly, angle change information of leg joints is obtained by breaking down leg movements of driver. Through analyzing the relationship of joint angle information and output displacement of hydraulic rod, output curve under normal operating conditions of the hydraulic drive system is calculated and is set to be target trajectory of control algorithm. Then, hydraulic position control system hardware and software are designed. In terms of hardware design, STM32F103VCT6 microcontroller is chosen as the core processor with other circuit modules designed around such as power supply circuit, arithmetic circuit, the data acquisition module and the interface module. In terms of software design, the initialization procedures, the servo valve control programs, the motor control programs and the PC programs are designed to implement system initialization, hydraulic stability control and target curve tracking. Finally, shore experiments and underwater experiments are conducted to verify the effectiveness of the control method by analyzing the step response curve and target tracking effect.