| Limited by the fixed base,the traditional working robot could hardly complete the work beyond its reach,resulting in the limitation of its working ability.Under the circumstance,the mobile robot technology has emerged.As a popular field in scientific research,various technologies such as dynamic planning decision-making and environmental perception have been involved in mobile robots.Of which,the legs-type mobile robot system has been favored by a wide range of research institutions for its strong adaptive capacity to environment.A coupling model of a multi-legged robot and a manipulator has been established in this paper to study its attitude and stability.Based on the working capacity of the multi-legged robotic system,a manipulator being applicable for working underwater in six degree of freedom has been designed in conjunction with the working capacity of the multi-legged working robot system.A dynamic model has been established for the manipulator using the Lagrangian method.Moreover,torques required for various joints of the manipulator have been verified with the MATLAB program written by the Monte Carlo method.By comparing the simulation result,the reasonable selection of the motor and the reducer has been verified.Meanwhile,a rotation open gripper of manipulator was designed for grasping.The kinematics modeling of the multi-legged robot grasping device and walking feet has been performed in accordance with the spatial posture representation of the object and the DH method.By specifying the corner range of various joints of the grasping device and the walking feet,the positive and athwart kinematics of device and the walking feet has been solved.Moreover,the resolving result has been verified through the visual model that was established by MATLAB and the included robot toolbox.And the inverse kinematics of the grasping device and the walking feet posture has been resolved using the machine posture of the multi-legged working robot.On this basis,the kinematics and working space of the multi-legged robot have been analyzed.To solve the problem of capturing base point range of a multi-legged robot,the manipulability has been determined as the indicator to solve the range of capture base points of the multi-legged robot through comparing methods of determining the kinematic performance of three manipulators from the perspective of the kinematic performance of the manipulator.The conclusion that the kinematic range of the joint at the end of the manipulator can be converged in space with the increase of the value of manipulability has been verified to verify the feasibility of solving the range of capturing base points for the multi-legged robot depending on the manipulability.According to the actual working conditions of the multi-legged robot,the stability of the multi-legged robot system has been analyzed with the stability margin of the force-angle.What's more,a method for solving the stable posture of the multi-legged robot has been proposed in line with the resolved value of stability margin.Solid joints of the grasping device have been commissioned before completing the whole machine testing and assembling,and the machine trial assembly of the device has been completed.High posture forward,middle posture normal,and slope normal and slope steady states have been set up for establishing corresponding models.And the tipping force of the robot was calculated with ADAMS.On this basis,the accuracy of the resolving method for stability margin has been verified through numerical comparison.Variation trends of stability margin of the robot have been calculated for analysis when its body moved back and forth,ups and downs,and pitches in the horizontal condition.At last,iteration has been employed to resolve the stable grasping posture of the robot under two different grasping conditions. |
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