Research On Bionic Soft Robot Based On The Kinematic Characteristics Of Cyriopagopus Hainanus

After hundreds of millions of years of natural selection through survival of the fittest,spiders have evolved special bio-hydraulic systems.There are two hydraulic joints in the spider’s leg,which rely on hydraulic pressure to extend and muscles to flex.They are able to achieve efficient drive and motion while maintaining low internal pressures and have the advantages of compact structure,high efficiency,stability and reliability.The biological characteristics have been studied in the aspects of biohydraulic driving principle and biomechanics,which provide many useful references for the development of spider-like robot.Biomimetic robot has developed from structural biomimetic which simply imitates biological movement in the early stage to biological biomimetic which is closer to biological prototype.The soft bionic robot that is more in line with the biological driving principle has better flexibility and adaptability.However,relevant research is still in primary stage and there are a large number of challenges.This paper aims to efficiently reproduce the advantages of the biological drive system and develop bionic robots that are closer to biological prototypes.Cyriopagopus hainanus was determined as the subject to analyze the locomotor mechanisms such as kinematic parameters and dynamic characteristics during 15° uphill and 15° downhill walking.Then the bionic design was carried out according to the hydraulic drive principle of the spider’s hydraulic joint.A bionic soft joint based on origami structure and a soft robot were developed.The main research work and related conclusions are as follows.1.Cyriopagopus hainanus was selected as the subject.The motion capture experimental system was built.Kinematic data at different speeds were obtained using a 3D motion capture and synchronization analysis system.In the wider range of0.027m/s to 0.691m/s,the kinematic parameters such as velocity,gait parameters and angle changes of hydraulic joints were calculated.Based on the energy fluctuation of the center of mass,the energy exchange mechanism and energy consumption during level walking were analyzed.It was found that a bouncing gait was mainly used by C.hainanus during level walking and their locomotor mechanism did not change with increasing speed.Because of the spiders’ hydraulic system,the mass-specific power per unit weight required to move the center of mass increased exponentially with increasing speed.The bouncing gait and the hydraulic system contributed to the lower transport cost at low speed,while the hydraulic system greatly increased the transport cost at high speed.2.To quantify the energy exchange and cost during slope walking and sure the effect of slope locomotion on energy cost,the experimental platform was adjusted to build a15° slope on the basis of the research on the locomotor mechanism of level walking.The motion capture system was used to obtain the mass center trajectory of C.hainanus when walking uphill and downhill on a 15° slope.And the kinematic and dynamic parameters at different speeds were obtained.Due to the large slope,the potential energy was the main component of the mechanical energy,and the energy exchange between kinetic and potential energy was little efficient.When walking downhill,little to no energy generation is required.Only the mechanical energy dissipation and a small amount of exchange occurred,still excluding the use of an inverted pendulum gait.When walking uphill,more mechanical energy was required.The positive mechanical work used to move was larger than the level walking.The mechanical work required to lift 1kg for 1m vertically was less than the theoretical value,highlighting spiders highly effective locomotor mechanics.3.According to the physiological structure and driving principle of spider hydraulic joint,a bionic soft joint based on origami structure was designed.Parametric design of origami structure was carried out according to geometric parameter calculation.The sample was directly 3D printed by soft silicone resin.The origami structure created rotary deformation and drive by folding and deploying the origami structure with soft surface,rather than simply expanding the material.The finite element analysis method was used to establish the model and analyze the different joints.The experimental platform was built,and the rotating characteristics and static driving performance of the sample were tested.The test results agreed with the simulation results.The bionic joint greatly increased the rotation angle due to the characteristics of origami structure,which verified the rationality and superiority of the structure design.By changing the parameter angle and the number of origami units,the output performance of the joint was changed to realize the customizability of the specific size determined according to the purpose.The bionic soft joint features linear drive performance,repeatability,customizable driving force and motion,and a high power-to-weight ratio.Based on the bionic joint,a bionic flexible gripper was developed.It can realize the adaptive grasping of 3.33 kg objects and has good grasping performance,which verifies the superiority of the bionic joint performance.4.Based on the characteristics that bionic joints can be parameterized,modularized and customized,a spider-like flexible driving robot was developed.The flexible driving principle and control system of the robot were determined by combining the spider biological fluid driving principle and motion characteristics.The walking characteristics of the robot were verified by experiments.The movement of the robot was tested under many conditions such as line walking,turning,loading and unstructured surface.The elastic mechanism and fluid drive system together constituted the energy source of the spider-like robot,effectively reproducing the excellent performance of the biological fluid drive system in nature.The robot can autonomously switch its gait according to the slope,with a maximum walking speed of 0.532bl/s and a load-bearing ratio of 17.937.It has simple manufacturing,light weight,low cost.The modular design of the drive joint made it easy to disassemble and replace.The robot performance can be customized by changing the parameters of bionic joint.It has good load-bearing capacity and high mobility,so it has great application potential in reconnaissance,transportation and other military fields.