Gait simulation of new robot for human walking on sand

In order to simulate the gait of human walking on different terrains a new robot with six degrees of freedom was proposed. Based on sand bearing characteristic compliance control was introduced to control system in horizontal and vertical movement directions at the end of the robot,and position control in attitude. With Matlab/Simulink toolbox,the system control models were established,and the bearing characteristics of rigid ground,hard sand,soft sand and softer sand were simulated. The results show that 0,0.62,0.89 and 1.12 mm are the maximal subsidences of the four kinds of ground along the positive direction of x-axis,respectively,and 0,-0.96,-1.99 and -3.00 mm are the maximal subsidences along the negative direction of x-axis,respectively. Every subsidence along y-axis is negative,and 0,-4.12,-8.23 and -12.01 mm are the maximal subsidences of the four kinds of ground,respectively. Simulation results show that the subsidence of footboard points to inferior anterior in early stage of stand phase,while points to posterior aspect in late stage. The subsidence tends to point to posterior aspect in the whole. These results are basically consistent with the gait characteristics of human walking on sand. Gait simulation of the robot for human walking on sand is achieved.

Kinematic Analysis and Experimental Verification on the Locomotion of Gecko

This paper presents a kinematic analysis of the locomotion of a gecko,and experimental verification of the kinematic model.Kinematic analysis is important for parameter design,dynamic analysis,and optimization in biomimetic robot research. The proposed kinematic analysis can simulate,without iteration,the locomotion of gecko satisfying the constraint conditions that maintain the position of the contacted feet on the surface.So the method has an advantage for analyzing the climbing motion of the quadruped mechanism in a real time application.The kinematic model of a gecko consists of four legs based on 7-degrees of freedom spherical-revolute-spherical joints and two revolute joints in the waist.The motion of the kinematic model is simulated based on measurement data of each joint.The motion of the kinematic model simulates the investigated real gecko's motion by using the experimental results.The analysis solves the forward kinematics by considering the model as a combination of closed and open serial mechanisms under the condition that maintains the contact positions of the attached feet on the ground. The motions of each joint are validated by comparing with the experimental results.In addition to the measured gait,three other gaits are simulated based on the kinematic model.The maximum strides of each gait are calculated by workspace analysis.The result can be used in biomimetic robot design and motion planning.