| With the improvement of people’s awareness of environmental protection and the requirements of sustainable development,water hydraulic transmission technology has become the focus of current hydraulic technology research due to its transmission medium water is pollution-free and recyclable.Flexible robot driven by water hydraulic has a wide application prospect in medical equipment,food processing and other fields because of its good flexibility,large load-to-weight ratio,green environment protection,short response time and so on.Especially in unstructured environment,such as deep-sea exploration and polar exploration.Firstly,it is difficult to control the pressure of the water hydraulic artificial muscle that make up the flexible arm with the existing water hydraulic valve.According to the existing water hydraulic valve technology,the hydraulic half-bridge circuit is used to control the pressure of hydraulic artificial muscle.The flow-pressure characteristics of A,B and C hydraulic half-bridge were analyzed,and the three hydraulic half-bridge circuits were simulated by AMESIM software.Finally,the C-type hydraulic half-bridge with simple principle that can output 0MPa pressure output is selected as the pressure regulating circuit of the water hydraulic flexible arm.Secondly,based on the working principle of C-type hydraulic half-bridge,a new type of proportional pressure control valve is designed.The water hydraulic proportional throttle valve is selected as the adjustable liquid resistance in the C-type hydraulic half-bridge,the manual throttle valve is used as the fixed liquid resistance.The structure of the proportional throttle is designed according to the design parameters,the proportional throttle and manual throttle is integrated into a valve to form a new type of proportional pressure regulating valve based on the C-type hydraulic half bridge.FLUENT and AMESIM software are used to simulate and analyze the designed valve.Thirdly,the water hydraulic driven flexible arm is designed based on the bionic principle and its kinematics is analyzed.According to the working principle of pneumatic artificial muscle,water hydraulic artificial muscle was designed and manufactured,and the static model of water hydraulic artificial muscle is analyzed.Then,according to the structure of octopus tentacles,a flexible arm composed of three water hydraulic artificial muscles is designed based on the bionic principle.The kinematic model of the flexible arm is established based on the geometric method.According to the kinematic equation,the kinematic space of the end of the flexible arm is solved by MATLAB,and the Workspace the end of the flexible arm is obtained.Finally,a pressure control experiment was carried out on a new type of proportional pressure control valve based on the C-type hydraulic half-bridge principle.At the same time,the new type of valve developed is used to control the driving pressure of hydraulic artificial muscles.The artificial muscles were tested for contraction characteristics and output force characteristics,and the flexible arm composed of artificial muscles are analyzed for bending and loading experiments.It is verified by experiments that the developed proportional pressure control valve realizes the characteristics of pressure regulation and the control of the bending state of the flexible arm. |
