Double layer control for AMT clutch in commercial vehicle starting: design and experiment

Abstract

Engagement control of an automatic mechanical transmission clutch during vehicle start-up has important influences on the safety, comfort, service life, energy consumption, and emissions of the vehicle. However, all existing control strategies use single-layer control, which leads to poor temperature adaptability. This paper develops a double-layer control strategy based on an automatic actuator to improve vehicle start-up performance. The governing characteristics of a diesel engine with a variable-speed governor are studied. The working principles and a model of the automatic actuator are described. A simulation of vehicle start-up is constructed and tested. Finally, the double-layer control strategy is verified in an experimental vehicle. The experimental and simulation results show that the double-layer control strategy provides shorter start times, less jerking, and lower friction, thereby demonstrating its effectiveness and practicability. Keywords: automatic mechanical transmission, start-up process, clutch engagement control, double-layer control Highlights • A double-layer control strategy is designed based on an automatic clutch actuator and controller. • Temperature changes affect clutch engagement performance during the vehicle start-up process. • Comparative outcomes verify the benefits of our scheme in terms of start time, jerking and friction work. • Experiments with an actual vehicle further validate the proposed control strategy.

Motion Characteristics of a Clutch Actuator for Heavy-Duty Vehicles with Automated Mechanical Transmission

“…. Then, F z (the force of the diaphragm acting on the pressure plate) can be expressed, calculated from Equation (15) according to Equations ( 8) and (14). The unit of F z in Equation ( 15) is N.…”

“…The displacement interval is 0.01 mm. Writing a MATLAB script program according to Equation (15), based on every given diaphragm large end displacement according to the displacement interval, the diaphragm force is calculated. In total, 1000 sets of data within engaging range and 200 sets of data within disengaging range are provided to plot the simulation curve of the diaphragm force in MATLAB.…”

“…To describe the release bearing force limited by the diaphragm large end, the release bearing displacement is divided into two parts: the force loading region is 16.20 mm, corresponding to the clutch disengaging travel displacement (12 mm), and the no force loading region is 6.90 mm, corresponding to empty stroke displacement. The release bearing force about its displacement from the beginning of the clutch disengaging process is calculated from Equation (16) according to Equation (15). The units of F b and x b are N and mm, respectively.…”

“…Szimandl et al studied a dynamic hybrid model of an electro-pneumatic clutch system, but the studying was limited to simulation [14]. Song et al proposed a double-layer control strategy based on a gas-assisted hydraulic clutch actuator, but the actuator's motion characteristics were not given [15]. Pisaturo et al studied thermal compensation control strategy in automated dry clutch engagement for commercial vehicles and proved the effectiveness in terms of simulation, but the experimental results were lacking [16].…”

Ramp Start and Speed Control of Self-Driving Commercial Vehicles under Ramp and Vehicle Load Uncertainty

“…With only minimal changes to the mechatronic system, the mechanical system consists of a gearbox-integrated hill-holding system, which can realize the hill-holding and automatic parking brake functions by purely mechanical or mechatronic means [15]. For heavy commercial vehicles, Song [16] et al realized the hill-hold function by changing the brake system structure to maintain a certain amount of oil pressure in the brake system at the moment when the driver releases the brake pedal. Peng [17] et al proposed a two-layer, large-scale adaptive control framework for commercial vehicles equipped with an electronic parking brake, using online estimation of the vehicle mass using the tractive force, braking force, road gradient, and longitudinal acceleration.…”