Qingxin Meng

Dexterous Underwater Robot Hand: HEU Hand II

Manipulator is the most important part for underwater flexible robot manipulation, and the grasping and manipulating capability is an important indication for intelligent robot. But current generation underwater robots generally employ the claw-like end effectors without sensing or controlling of the contact forces, which is simple and easy to control, but not able to perform complex operations. In this paper, a non-anthropomorphic underwater robot hand called HEU Hand II is presented, which is a modified version of HEU Hand I. The modular approach is adopted to design the hand, which have three identical fingers. Each finger has 3 joints with 3-DOF (degree of freedom), and two axes of the joints near the palm cross orthogonally at one point, as is the case in the human hand. The HEU Hand II can be equipped with 6-axis force/ torque sensor at each fingertip and position sensor in every joint. The characteristics of the hand, transmission mechanism, corrosion prevention and seal, sensor system, and control system are described and discussed. Moreover, the controller for the hand force tracking is designed based on PBNNIC (position-based neural network impedance control) scheme. The HEU Hand II has much improvements relatively to HEU Hand I, thus it is capable of grasping a wide variety of objects of different shapes, sizes and weights. The work area of the underwater robot can expand when HEU Hand II cooperates with the robot arm. It can be applied widely in the field of exploiting the resources under the sea

Influence Analysis of Toe-joint on Biped Gaits

In sagittal plane, 8-link model of biped with toe-joint is established and predigested into inverted pendulum. Inverse kinematics of single leg is analyzed, and Lagrange locomotion equation is established. The barycenter point motion track in space is presented and the effect of the gait with toe-joint in single leg supporting phase is analyzed by kinematics and dynamics simulation in Matlab. Through comparing gaits with toe-joint with which without toe-joint, the result shows that biped robot with toe-joint is more advanced in following aspects: walking step, walking speed, range of joint angle and the changing of angle velocity, joint energy-output and so on. The effect of toe-joint in biped walking robot is analyzed in theory. It is the base for gait design on impersonate robot

Analysis of Assistant Robotic Leg on MATLAB

Assistant robotic leg is a kind of robot designed for patients whose legs are injured or have difficulty in movement due to illness (i.e., diabetes, after-illness of the thrombus, etc). Each side leg has one degrees-of freedom motion at the hip and one degree-of-freedom at the knee. It is tied to the patients two legs to help them practice walking. Based on generalized coordinates, the kinematical model of the assistant robotic leg is done. Through analyzing the trajectories of hip joints and ankle joints developed by cubic spline interpolation, together with geometry restrains and motion restrains of humans, the parameterized model of bodys walking pattern is derived. The hip trajectory and the ankle trajectory are also obtained by image analyzing method and they are similar to the model derived from theory analyses. Finally it proves the theoretical analysis correct through the comparative analyses between simulation and image analyzing. Based on Matlab/Simulink, SimMechanics, the assistant robot leg is simulated

Dynamic Analysis on Fingers of the Underwater Multi-fingered Robot Hand

The dynamics is very important for the simulation and feedback-control design of the underwater-multi-fingered robot hand. But the dynamic of underwater-multi-fingered robot hand with many degrees of freedom is much more complicated if hydrodynamic terms are precisely treated, so the finger dynamics of underwater multi-fingered robot hand are analysed in the paper, and the precise dynamics model is established considering the drag force and added-mass force. Whats more, dynamic simulation is carried out by SimMechanics. The simulation result shows: the hydrodynamics forces are the most significant in magnitude, and the dynamic motion control must consider these parameters.

Dynamic Analysis of Rehabilitative Arm Robot

Rehabilitative robot is a new technology that has been developed rapidly. The robot is used to rehabilitate patients whose arms are injured or have difficulty in movement. The robot can move the disable arm in both horizontal and vertical plane, and train the shoulder joint and elbow joint. The human arm is simplified to rigid bodies and rotors. The robots structure and dynamics are analyzed. Including robot and human arm, the whole systems model is constructed under Matlab/Simulink Mechanics. Dynamics characteristics simulations of the flexing joint and rotation joint are made separately. With different damp coefficient of arm joints, the angle and angle acceleration curve of the shoulder and elbow are given. Control simulations are made too. The simulation results reveal the effectiveness of the dynamic model and the rehabilitation robot can do effective training on illness joints