Design And Experiment Of A Magnet-Orheological Fluid Based Robot Compliant Joint

With the development of robotics,people have put forward higher requirements for more tasks assigned to robots.At present,the task of relying solely on robots is relatively simple and mechanized.In order to complete more complex tasks,people need to be involved.Therefore,human-robot integration and human-robot cooperation are the main directions for the development of robots in the future.However,the traditional robots are made of rigid materials and rigid structures,and there is a risk of harm to people in the scene of human-robot cooperation.Therefore,in order to ensure the safety of people and robots,it is important to study robots with compliant performance.The existing compliant joints are mostly made of elastic material or lever principle to achieve the compliance of the robot joint.and they usually have one or more characteristic of large volume,high quality,high cost and so on,which is not suitable for the low-weight and low-mass design of the robot.In order to solve the above problems of the existing compliant robot joint,this dissertation adopts a method of realizing the compliance of the robot by using the magnetorheological fluid(MRF).And this dissertation puts forward to the performance index of the compliant module in the compliant joint and carries out the structural design of the compliant module.This dissertation builds a performance experiment platform based on the real-time simulation system dSPACE.Then this dissertation analyzes and tests the current-torque curve and stiffness step curves of the compliant joint.These experimental results show that the magnet-orheological fluid compliant joint meets the design requirements.And the joint has the characteristics of a faster response than other compliant joint.Based on the designed compliant module above,this dissertation designs a one degree-of-freedom MRF compliant joint.In order to achieve modular and integrated design of the compliant joint,this dissertation made a hardware control system based on STM32.Combined with the application of head injury criteria in the compliant robot,the peak compact force detection experiment platform using force sensor is built.The experiment verifies that the compliant speed and compliance are positively correlated with the compact force.The control strategy that is reducing the peak compacting force can be reduced when using High stiffness with high speed motion or low stiffness with low speed motion.And this strategy can be used to guide the future safety control of the MRF compliant joint.