Due to the excitation generated by the periodically alternate pumping of dual-hydraulic cylinders, vibration of concrete pump trucks (CPT) occurs. Excessive boom vibration will seriously affect the service life and operation safety of CPT. At the same time, the long boom structure of a CPT makes it very sensitive to the posture and pumping conditions, which directly affect the vibration characteristics of CPT in different postures and different working conditions. This paper establishes a finite element model of a type of CPT. Through force analysis of concrete in the straight pipe and elbow pipe during the pumping and reversing stages, an excitation model of the conveying pipe is established. Based on the secondary development of HyperWorks, a finite element model of CPT with multiple postures is built, and the dynamic response under multiple conditions is analyzed. Finally, the accuracy of the finite element model of CPT and the excitation model of the conveying pipe is verified by experiment.
To reduce the energy consumption and improve the stability of distributed drive electric vehicles, a torque allocation strategy based on an economy and stability optimisation function (ESOF) and a fuzzy proportional-integral-derivative rule control (FPRC) strategy are proposed while considering motor efficiency, braking energy recovery and motor failure. First, the vehicle dynamics and motor equivalent models are established. Subsequently, a torque prediction model and fuzzy controller for the vehicle are designed to calculate the total desired torque and yaw moment, respectively. A torque optimisation function is established to minimise power losses in the electric motor and maximise braking energy recovery, and it is solved using an improved genetic algorithm. While satisfying vehicle driving constraints, the ESOF-based controller can effectively coordinate the operation of each motor in the high-efficiency range under driving and braking conditions. After one motor fault is detected, the ESOF-based controller is replaced with an FPRC-based controller to distribute the vehicle demand torque. A co-simulation platform integrating MATLAB/Simulink and CarSim is developed to verify the effectiveness of the proposed ESOF-based controller in the New European Driving Cycle (NEDC) and Federal Test Procedure 75 (FTP75) driving cycles. The effectiveness of the FPRC-based controller in step steering condition is verified using the co-simulation platform. The simulation results indicate that the vehicle economy and driving range of the ESOF-based controller improved compared with the results afforded by the typical torque distribution strategy based on the front–rear axle dynamic load ratio. The average efficiencies of the motors in the NEDC and FTP75 driving cycles increased by 2.94% and 2.4%, respectively. More importantly, the FPRC-based controller can more significantly improve the steering stability of a vehicle with motor failure compared with the ESOF-based controller.
The All-Wheel-Independent-Driving (AWID) electric vehicle has big potential to improve driving capability. To make full use of ground adhesive force to improve the driving capability, a dynamic model with 18 degrees of freedom (DOF) for 6WID electric vehicle is established in this thesis. A kind of torque distribution strategy based on load ratio is brought forward, with an antiskid PI control algorithm. The dynamic system model of the vehicle is co-simulated with Adams and Matlab/Simulink. The comparative experiment shows that this kind of driving force distribution strategy can improve the driving capability of the vehicle.
Index Terms-6WID Electrical Vehicle, Wheel Motor, Dynamic Model, Torque Distribute Strategy
The All-Wheel-Independent-Driving (AWID) electric vehicle has complex stress situation on off-road environment. To observe the load of each wheel, a dynamic model with 18 degrees of freedom (DOF) for 6WID electric vehicle is established in this thesis. The kinetic equation to solve wheel loads is created by Newton-Euler method. The load of each wheel is calculated according to their geometrical relationship with the whole vehicle. A wheel load observer is brought forward. The dynamic system model of the vehicle is co-simulated with Adams and Matlab/Simulink. The comparative results shows that this kind of observer can improve the wheel load observation accuracy effectively.
Index Terms-6WID Electric Vehicle, Wheel Load Observer, Off-Road Environment
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