Structure design and analysis of aid walking mechanism for a lower limb rehabilitation robot

In order to improve the rehabilitative effect of users＇ recovery training and reduce the production cost of rehabilitation institution, this paper designs an aid walking mechanism for a lower limb rehabilitation robot which achieves the movement of transmission by use of the interrelationship between hip and knee. Using single chip micyoco （SCM） control technology to achieve the coordinated operation of the entire mechanical institution, this aid walking mechanism simulates the walking gait. Besides, this paper also verifies that materials＇ strength meet the design requirements by Solidworks simulation stress-strain analysis module.

Gait analysis of goat at different slopes and study on biomimetic walking mechanism

To study the walking status of a goat on slope and the walking mechanics,a comparative analysis of the walking gait mode of a goat on different slopes was conducted.The uphill and downhill walking processes on different slopes(6°,18°and 36°)were recorded by a high speed video system.The experimental image results were processed and analyzed via SigmaScan software and MATLAB software.The characteristic parameters of locomotion gait on the different slopes and the angle change curves of each goat leg in the process of slope movement indicated that the goat performed tetrapod gait,static gait,ipsilateral gait and trot gait on different slopes.With the increase of gradient in the uphill process,the corresponding load factors of each leg were 0.65±0.15,0.75 and 0.645±0.205,whereas those in the downhill process were 0.70±0.08,0.66±0.06,and 0.685±0.125.Results showed that the load factors of each leg are higher than 0.5.The foreleg angle ofa(the angle of wrist joints),which ranges from 100°to 130°,is suitable for different slopes.However,the angle ofb(the angle between the thigh and the forward direction in the walking process of goat),which ranges from 99°to 109°,is suitable for the 6°slope,whereas the angle ranging from 46°to 91°is suitable for the 18°slope and 36°slope.For the hind leg,the angle ofa,which ranges from 105°to 153°,is suitable for the different slopes.The angle ofb,which ranges from 128°to 150°,is suitable for the different slopes.The research can provide a theoretical basis and experimental data for the design of biomimetic agricultural slope walking mechanism.

ANALYZING ON THE VIBRATION CHARACTERISTICS OF A MICRO PIEZOELECTRIC ROBOT IN PIPELINE

The mathematical model of a micro piezoelectric elastic legged robot in pipeline was founded. The robotic resonant frequency worked out with the mathematical model is nearly equal to the frequency from experiment. It indicates that the mathematical model of the robot is correct. Besides, it studied the piezoelectric robotic structure parameters’ effect on the robotic performance. The result of the analysis on the robot constructs the base of an optimal design of a piezoelectric robot.

Application of Parallel Mechanism in Varistructured Quadruped/Biped Human-carrying Walking Chair Robot

For the existing problems of walking chair robot such as simple function,lower bearing capacity and not walking in complex environment,a novel varistructured quadruped / biped human-carrying walking chair robot is proposed.The proposed robot could be used as biped and quadruped walking chair robots.Considering the conversion of the walking chair robot from the quadruped to the biped or vice versa,6-UPS and 2-UPS＋UP（U,P and S are universal joint,the prismatic pair,and sphere joint,respectively） parallel mechanisms are selected as the leg mechanism of the biped walking robot and quadruped walking robot,respectively.Combining the screw theory and theory of mechanism,the degrees of freedom of the leg mechanism and the body mechanism in diferent motion states are computed so as to meet the requirements of mechanism design.The motion characteristics of the 2-UPS＋UP parallel mechanism which is the key part of the walking chair robot are analyzed.Then,the workspace of the moving platform is drawn and the efect of the structural parameters on the workspace volume is studied.Finally,it is found that the volume of the workspace of the moving platform is bigger when the side length ratio and the vertex angle ratio of the fxed platform and the moving platform which are isosceles triangles are close to 1.This study provides a theoretical foundation for the prototype development.