Modeling and Simulating for TSHD’s Swell Compensator by ADAMS

CHC Trailing suction hopper dredgers (TSHD) have been widely used in dredging industry. In order to simulate the dredging process accurately, a mathematical model for a swell compensator used in TSHD is proposed, and a friendly simulation model based on the Automated Dynamic Analysis of Mechanical Systems (ADAMS) is built to test and validate the mathematical model for the swell compensator. The factors influencing the dynamic behavior of the TSHD suction pipe system, such as the mo-tion of the vessel in an unquiet situation with different water current velocities, seabed profiles, seabed soil hardness and the forces acting on the suction pipe system, have been taken into consideration. The simulation results show that they fit in with the operat-ing practice qualitatively.

Design and motion analysis of reconfigurable wheel-legged mobile robot

An adaptive wheel-legged shape reconfigurable mobile robot,based on a scissor-like mechanism,is proposed for an obstacle detecting and surmounting robot,moving on complex terrain.The robot can dynamically adjust its own shape,according to the environment,realizing a transformation of wheel shape into leg shape and vice versa.Each wheel-legged mechanism has one degree of freedom,which means that only the relative motion of the inner and outer discs is needed to achieve the transformation of the shape into a wheel or a leg.First,the force analysis of the conversion process of the wheel-legged mechanism is carried out,while the relationship between the driving torque and the friction factor in the non-conversion trigger stage and in the conversion trigger stage is obtained.The results showed that the shape conversion can be better realized by increasing the friction factor of the trigger point.Next,the kinematics analysis of the robot,including climbing the obstacles,stairs and gully,is carried out.The motion of the spokes tip is obtained,in order to derive the folding ratio and the surmountable obstacle height of the wheel-legged mechanism.The parameters of the wheel-legged structure are optimized,to obtain better stability and obstacle climbing ability.Finally,a dynamic simulation model is established by ADAMS,to verify the obstacle climbing performance and gait rationality of the robot,in addition to a prototype experiment.The results showed that the surmountable obstacle height of the robot is about3.05 times the spoke radius.The robot has the stability of a traditional wheel mechanism and the obstacle surmount performance of a leg mechanism,making it more suitable for field reconnaissance and exploration missions.

Dynamic modeling and analyzing of a walking robot

In this paper, a walking robot is established. The zero-moment point（ZMP） is used to stabilize the working robot. The kinematic model of the robot based on denavit-hartenberg（D-H） method is presented in this thesis. And then the dynamic model, based on Lagrange method, is built by simplifying the kinematic model of robot body. A kinematic simulation to the robotic system is achieved based on Adams. Driving torque of left ankle is calculated according to joint angle, angular velocity and angular acceleration. The validity of the dynamic model is testified by comparing with the result of simulation.