Autonomous shoveling of loaders is the key technology to realize automatic and intelligent operation,and the tracking control of the target working trajectory is one of its core parts.The actual trajectory of the bucket in the pile is related to the indicators such as the operation output,so it is of great significance to realize the effective track-ing control of the target working trajectory.The PID and other control methods without system models have prob-lems such as large overshoot amplitude and buffeting under the system constraints.Since the Model Predictive Con-trol(MPC)has the advantage of effectively dealing with system constraints to make the system operate smoothly,it was introduced into the motion control of the loader's working mechanism and a trajectory-tracking control method was proposed for the working mechanism based on the Nonlinear Model Predictive Control(NMPC).A kinematic model of the working mechanism in the drive space was established.Then,the description of the working trajectory was given.Furthermore,a trajectory-tracking controller for the working mechanism was designed based on the NMPC method.Finally,the Simulink/ADAMS co-simulation was carried out with the general PID as the compari-son group.The analysis showed that under the same system constraints,for the different target trajectories,the maximum absolute error of the bucket-tip displacement based on the designed controller didn't exceed±0.052m,which was 71％lower than the PID controller,and the maximum absolute error of the bucket angle didn't exceed±2.58°,which was 16％lower than the PID controller.Moreover,the designed controller had a smoother control effect.The designed controller had better performance than the PID controller in dealing with system constraints and smoothness.

Achieving precise load detection for Intelligent Loaders is an important task, which directly affects the operation energy efficiency and the fatigue life analysis for the loader’s working mechanism. The operation of the mechanism is regarded as a 3-DOF (degree of freedom) planar motion process coordinated with the vehicle body. Affected by complex dynamic coupling in motion, the existing dynamic models of the mechanism have the problem of insufficient accuracy, which is not conducive to the precise calculation of load. Taking the reverse six-linkage loader as the research object, an accurate dynamic model of the mechanism is established considering its cooperative motion with the vehicle body. Firstly, the kinematic description of the mechanism is given by the Rodriguez method. Then, to overcome the coupling effect caused by the cooperative motion, the sufficient inertia forces of the mechanism are established in joint space using the Lagrange method. Furthermore, to overcome the coupling effect caused by the complex structure, the Newton–Euler method is used to establish the force mapping relations between the joint space and the drive space by multi-body modeling. Finally, the dynamic model of the mechanism in drive space is obtained, and the specific mapping relations between the bucket force, the vehicle driving force, and the drive parameters are given. Compared with existing dynamic models in simulation, the analysis shows that the average and maximum absolute errors of the vehicle driving force calculated by the established model do not exceed 20% of the existing model errors, and the corresponding errors of the bucket force do not exceed 10% of the existing model errors, which proves that the motions of vehicle body and front-end mechanism, as well as the force of the tilt hydraulic cylinder, play important roles in improving the model accuracy. The established model is superior to existing models and is more suitable for cooperative motion with the vehicle body.

In the field of path tracking for car-like robots, although nonlinear model predictive control (NMPC) can handle the system constraints well, its real-time performance is poor. To solve this problem, a neural network control method with NMPC as the learning sample is proposed. The design process of this control method includes establishing the NMPC controller based on the time-varying local model, generating learning samples based on this NMPC controller, and training to obtain the neural network controller. The proposed controller is tested by a joint simulation of MATLAB and Carsim and compared with other controllers. According to the simulation results, the accuracy of the NN controller is close to that of the NMPC controller and far better than that of the Stanley controller. In all simulations, the absolute value of displacement error of the NN controller does not exceed 0.2854 m, and the absolute value of heading error does not exceed 0.2279 rad. In addition, the real-time performance of the NN controller is better than that of the NMPC controller. The maximum time cost and average time cost of the NN controller are, respectively, 40.91% and 22.37% smaller than those of the NMPC controller under the same conditions.

Automatically and accurately obtaining payload information from Load-Haul-Dump (LHD) vehicles is a typical application of information and intelligence technology in engineering equipment, which provides an important support for efficient and safe construction. In this paper, a novel comprehensive weighing model for LHD with high accuracy and adaptability is proposed by Newton-Euler method. The accuracy of the model has been greatly improved with the consideration of some critical factors such as materials randomness, driving cylinders coupling, dynamic characteristics of mechanism, system damping and working pavement. The effect of the critical factors on the accuracy of weighing model is deeply analysed through significance analysis and comparison tests, which provides an important basis for the improvement of weighing model. Validation shows that the novel model is superior to traditional models in accuracy and adaptability. In theory, the accuracy of novel model is at least 3 times higher than that of traditional models, and its accuracy can still achieve ±0.3% in complex velocity or acceleration motion, and the larger the load mass, the higher the accuracy. As a result, the novel comprehensive weighing model can provide accurate load information for LHD vehicles without affecting working efficiency. It is of great theory and application value to the development of information and intelligence technology in engineering equipment and contributes to efficient and safe construction.

We propose an optimal planning scheme of the bucket trajectory in the LHD (Load-Haul-Dump) automatic shoveling system to improve the effectiveness of the scooping operation. The research involves simulation of four typical shoveling methods, optimization of the scooping trajectory, establishment of a reaction force model in the scooping process and determination of optimal trajectory. Firstly, we compared the one-step, step-by-step, excavation and coordinated shoveling method by the Engineering Discrete Element Method (EDEM) simulation. The coordinated shoveling method becomes the best choice on account of its best comprehensive performance among the four methods. Based on the coordinated shoveling method, the shape of the optimized trajectory can be roughly determined. Then, we established a model of bucket force during the shoveling process by applying Coulomb's passive earth pressure theory for the purpose of calculating energy consumption. The trajectory is finally determined through optimizing the minimum energy consumption in theory. The theoretical value is verified by the EDEM simulation.