Study On Bionic Multi-legged Robot Based On The Hydraulic Driving Principle Of Spider Foot

Multi-foot walking robot has strong maneuverability and ability to adapt to uneven ground,and can meet the needs of various uses such as military reconnaissance,resource exploration and emergency rescue.Its driving methods are divided into hydraulic drive,pneumatic drive,electric drive and other forms.Among them,the hydraulic drive has the advantages of outputting large driving force and torque,simple and compact structure,and high positioning accuracy,but it also has the disadvantages of low efficiency and low power density.In order to solve the above problems,this dissertation relies on the Ministry of Education Equipment Joint Fund(6141A02022614),whose purpose is to develop a high-power density,high-efficiency hydraulically driven hexapod robot from the analysis of the spider's hydraulic drive mechanism.The main research contents of this dissertation are as follows:First of all,Hainan bird spider is taken as the object of bionic research.A selfdesigned test method was used to study the internal flow law of the femur–patella hydraulic drive joint on the spider foot,and then the joint angle-volume characteristic curve of the drive joint was obtained.Based on the change law of this curve,the calculation formula was constructed using MATLAB software,which paved the way for further exploring the spider hydraulic driving mechanism and energy transfer process.Secondly,according to the physiological structure and driving principle of spider footsteps,an innovative spider-like integrated bidirectional joint is designed,which highly replicates the function of footsteps.The spider foot is driven by the antagonism of lymph fluid pressure and muscle force.Therefore,in order to imitate the role of the lymph fluid in the spider leg,the expansion of the joint is achieved by the hydraulic pressure pushing the piston.At the same time,in order to imitate the action of the muscles in the spider's legs,the contraction of the joint is achieved by the contraction of the artificial tendon.The size of the joint is designed based on a fixed-size artificial tendon,and the position of the hinge point at the joint is optimized,so that it can achieve a gentle force under the premise of meeting the target joint rotation angle.The optimized mechanism was simulated and analyzed,and the rationality and feasibility of the designed mechanism were verified based on the obtained relevant curve data.Since then,the spider's bionic foot has been used as the movement and driving unit to design the single leg and the overall structure of the hexapod robot.And in order to adapt to multi-terrain working conditions,a switching mechanism capable of quickly switching between the two modes of wheeled walking and foot walking was designed.The hexapod robot walking in a triangle gait was simulated and analyzed using ADAMS software.The simulation results showed that the hexapod bionic robot moved smoothly and the energy loss during walking was not large.In addition,in order to ensure that the robot can still walk stably after being subjected to external forces,the strength of key components was checked using finite element analysis software.The results show that the designed mechanism meets the requirements of use.Finally,due to time and cost constraints,only the single-leg principle prototype of the hexapod robot was manufactured and tested to verify the rationality and feasibility of the designed robot.The test content includes single leg swing performance and the efficiency and power density of the hydraulic drive system.The test results show that the single-leg mechanism can swing according to the desired joint rotation angle and trajectory;the efficiency of the hydraulic drive system has reached more than 75%;the power density has increased by more than 15% compared to the traditional hydraulic drive system.The above results show that the use of spider hydraulic drive mechanism can bring about the improvement of robot performance.