Purpose: A simulator for the design and performance evaluation of a tractor with a hydro-mechanical transmission (HMT) was developed. Methods: The HMT consists of a hydro-static unit (HSU), a swash plate control system, and a planetary gear. It was modeled considering the input/output relationship o...
Purpose: A simulator for the design and performance evaluation of a tractor with a hydro-mechanical transmission (HMT) was developed. Methods: The HMT consists of a hydro-static unit (HSU), a swash plate control system, and a planetary gear. It was modeled considering the input/output relationship of the torque and speed, and efficiency of HSU. Furthermore, a dynamic model of a tractor was developed considering the traction force, running resistance, and PTO (power take off) output power, and a tractor performance simulator was developed in the co-simulation environment of AMESim and MATLAB/Simulink. Results: The behaviors of the design parameters of the HMT tractor in the working and driving modes were investigated as follows; For the stepwise change of the drawbar load in the working mode, the tractor and engine speeds were maintained at the desired values by the engine torque and HSU stroke control. In the driving mode, the tractor followed the desired speed through the control of the engine torque and HSU stroke. In this case, the engine operated near the OOL (optimal operating line) for the minimum fuel consumption within the shift range of HMT. Conclusions: A simulator for the HMT tractor was developed. The simulations were conducted under two operation conditions. It was found that the tractor speed and the engine speed are maintained at the desired values through the control of the engine torque and the HSU stroke.
Purpose: A simulator for the design and performance evaluation of a tractor with a hydro-mechanical transmission (HMT) was developed. Methods: The HMT consists of a hydro-static unit (HSU), a swash plate control system, and a planetary gear. It was modeled considering the input/output relationship of the torque and speed, and efficiency of HSU. Furthermore, a dynamic model of a tractor was developed considering the traction force, running resistance, and PTO (power take off) output power, and a tractor performance simulator was developed in the co-simulation environment of AMESim and MATLAB/Simulink. Results: The behaviors of the design parameters of the HMT tractor in the working and driving modes were investigated as follows; For the stepwise change of the drawbar load in the working mode, the tractor and engine speeds were maintained at the desired values by the engine torque and HSU stroke control. In the driving mode, the tractor followed the desired speed through the control of the engine torque and HSU stroke. In this case, the engine operated near the OOL (optimal operating line) for the minimum fuel consumption within the shift range of HMT. Conclusions: A simulator for the HMT tractor was developed. The simulations were conducted under two operation conditions. It was found that the tractor speed and the engine speed are maintained at the desired values through the control of the engine torque and the HSU stroke.
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제안 방법
The HMT was modeled considering the efficiency and response of the HSU. For the efficiency of the HSU, the test results of the efficiency with respect to the stroke, operating speed, and pressure were used, and dynamic models for the HSU swash plate control system and hydraulic control valves were derived. For the planetary gear of the HMT, the output speed and torque were modeled with the engine speed and torque, and the HSU stroke.
In this study, a simulator that can be used for the design and performance analysis of HMT tractors was developed based on the dynamic model of the HMT by considering the HSU, swash plate control system, planetary gear, tractor longitudinal dynamics and load characteristics. Using the simulator, performance of the HMT tractor was investigated.
Based on the dynamic models of the HMT tractor, a performance simulator was developed. The HMT tractor simulator consists of the AMESim model of the HMT, engine and tractor dynamics and MATLAB/Simulink interface of the driver model, a controller, and a road load. Using the simulator, the performance of the HMT tractor was evaluated for the working mode and driving mode.
대상 데이터
HMT consists of an HSU and a planetary gear. The planetary gear is composed of single pinion planetary gears (SPPG) and has an output split structure, where the planetary gear is located at the output side.
HMT consists of an HSU and a planetary gear. The planetary gear is composed of single pinion planetary gears (SPPG) and has an output split structure, where the planetary gear is located at the output side. In this study, it was assumed that the planetary gear has a single-speed with gear ratio of 1:2.
이론/모형
Many researchers have analyzed these characteristics through empirical methods. In this study, the model suggested by Brixius was used (Brixius, 1987; Grisso et al., 2003; 2007).
성능/효과
At this moment, the control targets were selected as (1) the desired engine speed of 1700 rpm to maintain the PTO speed of 600~700 rpm and (2) the tractor speed of 8 km/h. The simulation results show that the tractor speed and engine speed decreased due to the effect of the stepwise increase of the drawbar load at t=32s, but the engine speed was maintained at the desired speed at t=37s by the engine torque and HSU stroke control(Figure 11b, c). The tractor speed followed the desire value at t=44s after 12s due to the tractor inertia (Figure 11e).
후속연구
As the gear shift of HMT is performed by considering the HSU and the load characteristics, a study on the HSU, which is used as a continuously variable transmission variator in HMT, should first be required. The past studies on the modeling and hydraulic characteristics analysis of HSU include a study by Steyr on the mathematical modeling of the pump, motor, and swash plate of HSU used in the S-matic transmission (Aizetmüller, 2000; Kugi et al.
참고문헌 (12)
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