Abstract:Aiming at the problem that traditional force sensors can not realize accurate tactile sensing of robots in bioengineering field,a micro-hydraulic drive mechanism which could measure the mechanical properties of viscoelastic materials was proposed.The reaction force and displacement were measured by directly contacting the target object,and the tip of the end effector was composed of a miniature cylinder,which was amplified by using Pascal principle.The optimal size of the micro cylinder was analyzed,and the liquid supply system of micro hydraulic drive mechanism was given.The creep experiments and measurement and identification experiments were carried out on viscoelastic materials with different hardness by using micro-cylinder with inner diameter of 1.6 mm.According to the discrete displacement and load data,the stiffness and viscosity coefficient of the contact object were calculated by using Kelvin model and standard linear solid model respectively.The results show that compared with the standard linear solid model,the stiffness and viscosity coefficient estimated by using the micro-hydraulic drive mechanism based on Kelvin model are closest to the real values,which can meet the requirements of high-precision mechanical property measurement in robot palpation system.