Research On Riding Performance Of Articulated Tracked Vehicle

As articulated tracked vehicle has a good traffic ability, it is extensively used in military affairs, fire fighting of forest region and succor campaign etc. The two vehicle-bodies of articulated tracked vehicle are capable of locomotion of three freedoms by articulated mechanism, including yaw, pitch and roll. The yaw and pitch motion will be controlled by two series of hydraulic cylinder, and they make the track and ground match well. More uniform pressure can be achieved, thus the vehicle maintains greater traction. It enhances the traffic ability of the articulated tracked vehicle.Analysis of the kinematics and dynamics of the travel mechanism and articulated mechanism is showed in the paper. In addition, the traction performance of the articulated tracked vehicle is calculated, and dynamics of pivot steering and proriding steering basing on the characteristic of the mobile mechanism and articulated mechanism is researched. These provide the theory for vehicle simulation.In the paper, the hinge points location of articulated mechanism is optimized by AutoDesign module of RecurDyn software, and effect analysis of each parameter is showed after the Design of Experiment (DOE). The comprehensive performance of optimized articulated mechanism is better than primary articulated mechanism.The virtual prototype of articulated tracked vehicle and driving model are set up by Professional and Colink module in RecurDyn software in the paper. The results of simulating the process of climbing slope with rigid road, clay, heavy clay and sand show that the vehicle can climb up a sixty percent slope except clay, but it can climb up a forty percent slope with clay. The research also reveals that the traffic ability will rise up if the differential is turned off. However, it is not obvious on the sand, because obtaining the max traction of the vehicle is greater on the sand. A certain extent, the height of grouser will effect the traffic ability. If the grouser is higher, the traffic ability only on the viscous road will be better. Result of studying the climbing traffic ability after the travel mechanism failed partly indicates that it will have a better climbing traffic ability when the rear part is driven.After simulated the pivot steering of articulated tracked vehicle, get the steering torque on different road, and get the steering stability of both front part and rear part. In the riding steering simulation, set up a PID control model to drive by speed, analyse the effects on vehicle steering capability(such as, effect on steering radius, steering inaccurateness, and steering torque etc.)about speed, the mass ratio of front part to rear part, distance between hinge point and the geometry center of front part, distance between hinge point and the geometry center of rear part and steering angle. The simulation on steering reveals the performances of vehicle steering. It can direct people to drive and manipulate the vehicle well.The simulation on passing a ditch with 4meter depth and a perpendicular obstruction with 1.5meter height shows the stability of the vehicle, the force state on pitching hydraulic cylinders, dynamic load on each wheel system, the PSD (power spectral density) based on the acceleration in three direction in both the center mass of vehicle body and driver seat, evaluate the ride comfort when pass obstructions by weighted acceleration RMS (root mean square) of 1/3 frequency multiplication.The result of simulation shows that the virtual prototype of articulated tracked vehicle is correct, and it can climb up sixty percent slope, steer, pass 4m breadth ditch and 1.5m height obstruction, so it can meet the vehicle design requirement. The driver will not feel uncomfortable when the vehicle is passing an obstruction. In addition, it proves that applying virtual prototype technology which is based on multi-body dynamics to articulated tracked vehicle design is feasible. Especially, the examine cost is reduced, and it is useful for studying articulated tracked vehicle. The method in the paper is valuable to researching and designing other mechanisms.