Study on the Tracked Vehicles HMCVT Test-Bed and Its Control & Test System

Abstract

The hydro-mechanical continuously variable transmission (HMCVT) is a new type transmission device, which consists of a mechanical transmission (MT) combined in parallel with a hydrostatic transmission (HST) featuring a pair of hydraulic units. The HMCVT has a continuously variable shifting ratio by the combination of HST and MT and achieves high efficiency by MT. The bench test is the important part in the research and development of HMCVT. By the bench test, these works can be carried out, such as the performance testing, the property matching of vehicle transmission, the determination of control method. In this paper, the test-bed and its control system of HMCVT assembled in DFH1302R tracked tractor are presented. The engine model and vehicle's running resistance model are established. The control principles of simulative system of engine and running resistance are studied. The communication principles of distributed control system are also discussed: the slaver computers control the throttle of engine and the eddy current dynamometer; the master computer exchanges information with the slaver computers by serial communication; the master computer collects all signals by data bus; the human-computer interaction is carried out with the virtual instrument software. The experiment results show that control test system of the HMCVT test-bed can satisfy and fulfill the test demand of the HMCVT prototype.

Modeling and Simulation of Disc Brake Resistance Load in Low Speed Condition

“…3 Under the low speed condition, no matter the acceleration is constant or variable, the error of load is less than 10 N•m except in the condition of load step with a larger error ( error value of 87.5 N•m ), disc brake load applied is almost equal to the load setted basically. 4 In the test, by controlling the disc brake braking output torque by controling the input voltage of the electrohydraulic control portion in the disc brake, the simulation of crawler vehicle driving resistance, and it has high accuracy, fast response speed, it has better dynamic characteristic.…”

“…The torque control volume ( torque set-point ) is measured by torque-speed sensor . The tracked vehicle driving resistance∑F [4] is equivalent to the transmission output shaft, the transmission output shaft resistance torque Mbs is simulated by the braking torque generated by the disc, as:…”

Method and Test Bench for Hydro-Mechanical Continuously Variable Transmission Based on Multi-Level Test and Verification

“…Some scholars have carried out theoretical calculations and analysis on the design scheme and established a simulation model of the overall scheme for simulation analysis and verification [9][10][11]. Based on simulation analysis and verification, some scholars confirm the rationality and correctness of the simulation model by verifying the physical prototype through the test bench or comparing the installation verification with the simulation results [3,8,[12][13][14][15][16]. The main factors affecting transmission efficiency are hydrostatic CVT, mechanical transmission system, and the interaction between them.…”

“…Xia et al [20] and Kumar et al [21] adopt the experimental test data and a polynomial curve fitting method for the hydrostatic CVT. Some scholars analyzed the simulation and experimental verification of individual hydrostatic CVT, and then analyzed it combined with HMCVT [12][13][14][15][16][17][18][19][20][21][22][23][24][25]. The power split device and the power junction device mainly realize mechanical transmission through gear transmissions, which the oil mixing loss also has some impact on the transmission efficiency.…”