Internal Pressure Analysis And Application Of Soft Actuator With Pneumatic Network

Pneumatic network soft actuator have become one of the most widely used actuator for soft robots due to their high safety,strong environmental adaptability,and pollution-free characteristics.They are highly used in space exploration,search and rescue systems,bionics,medical surgery,and rehabilitation.Application potential.existing research on soft actuators focuses on the establishment of a kinematic model to predict the movement of the actuator,and does not consider the change of internal pressure during the movement of the actuator.In order to explore the change of internal pressure during the movement of the actuator,the actuator is simplified into an elastic tube,the control equation of the internal gas flow is derived,and the influence of the internal pressure change of the actuator on the movement under different structural parameters is analyzed.The main contents are as follows:In order to explore the influence of the change of the internal pressure of the actuator on its motion,the actuator is simplified into an elastic tube and the control equation of the fluid flow inside the actuator is derived.The pressure change inside the actuator is obtained by solving the control equation.The results show that the pressure distribution inside the actuator It is not uniform,and the pressure near the inlet increases instantaneously,and gradually decreases along the flow direction.With the inflation time,the internal pressure gradually rises and reaches a stable state.The motion of the actuator under this pressure change is analyzed.The analysis results show that the dynamic change of the internal pressure will affect the bending motion of the actuator,and there is an obvious delay in the motion of the actuator.In order to explore the influence of actuator pressure changes on motion under different structural parameters,the internal pressure changes of the actuator are analyzed under different pipe radii and pipe lengths of the actuator.The analysis results show that when the pressurized gas passes through a larger pipe diameter,The pressure inside the actuator rises quickly,but when the pressurized gas passes through a smaller pipe,its internal viscous resistance increases sharply,which will hinder the flow of the gas in the pipe,and the internal pressure rise rate slows down,and different pressure changes are analyzed.The impact on the movement of the drive.A prototype of the actuator is made for experiments.The experimental results show that the time required for the actuator to complete the movement is inversely proportional to the radius of the pipe and directly proportional to the length of the pipe.The radius of the pipe is the main influencing factor.Based on the characteristics of the smaller the actuator's pipe radius,the slower the actuator's moving speed,a three-joint soft actuator was designed.By changing the radius of the inner pipe of the soft actuator,the sequential expansion of the three joint chambers was realized.Experiments show that sequential bending can enhance the adaptability of the soft drive and reduce the end output force of the soft drive,with a maximum reduction of 50%.Using the three-joint soft actuator,a soft hand that can bend each finger sequentially under the action of a single input source is prepared.Using the characteristics of the actuator's end force reduction and sequential bending,the non-destructive and stable gripping of soft objects(bread)is realized.Comparing the motion of the soft actuator at different inflation and deflation frequencies,it is found that as the frequency increases,the bending motion angle of the actuator also decreases.When the frequency is above 5.0 Hz,the bending motion angle of the actuator is very small,and Vibrate at this frequency at a very fast speed.The influence of the radius of the pipe is analyzed.Under the same charging and discharging frequency,when the frequency is less than 2 Hz,the bending speed of large pipe diameter is fast;when the frequency is greater than 2 Hz,the bending speed of small pipe diameter is fast.Using this feature,a soft crawling robot is designed.Under 50 k Pa input air pressure and 1Hz charging and discharging frequency,a robot with a body length of 80 mm and a pipe diameter of 0.5mm can crawl 100 mm in only7.1s.Experiments show that it can be controlled by charging and discharging.The air frequency increases the crawling speed of the robot.