CPC B60G 17/018 (2013.01) [F15B 13/024 (2013.01); B60G 2202/413 (2013.01); F15B 2211/405 (2013.01)] | 4 Claims |
1. A hydraulic active suspension flow control system, comprising:
a hydraulic oil tank,
a variable displacement pump with an oil suction port communicating with the hydraulic oil tank,
a check valve,
a servo valve,
a suspension cylinder controlled by the servo valve,
an engine revolution speed sensor configured to detect an engine revolution speed,
a vehicle speed sensor configured to detect a vehicle speed,
an oil pressure sensor configured to detect an accumulator outlet pressure,
a flow controller configured to control displacement of the variable displacement pump by receiving data from the engine revolution speed sensor, the vehicle speed sensor and the oil pressure sensor, and
a relief valve connected to the check valve in parallel and provided at an oil outlet of the variable displacement pump;
wherein the check valve, servo valve, and suspension cylinder are connected to the oil outlet of the variable displacement pump in sequence; the variable displacement pump is connected to an engine through a clutch; and an accumulator is connected between the servo valve and the check valve;
the flow controller is configured for closed-loop control based on an accumulator outlet pressure, a vehicle speed and an engine revolution speed by the following method:
firstly, calculating, based on changes of the accumulator outlet pressure, a first displacement adjustment quantity of the variable displacement pump:
Δv1=k1(p0−p1),
wherein p0 denotes a preset pressure threshold, p1 denotes the accumulator outlet pressure, and k1 denotes a proportionality coefficient;
secondly, calculating, based on the vehicle speed and engine revolution speed detected in real time, a second displacement adjustment quantity of the variable displacement pump by the following method:
(1) calculating an average flow provided by the variable displacement pump and an average vehicle speed within t0 seconds before a current moment:
wherein qaverage denotes the average flow provided by the variable displacement pump within t0 seconds, qaverage denotes the average vehicle speed of a vehicle within t0 seconds, vt, nt and ut denote instantaneous displacement of the variable displacement pump, an instantaneous engine revolution speed and an instantaneous vehicle speed at a moment t respectively, and tc denotes sampling time; and
(2) calculating, based on the average flow provided by the variable displacement pump, a current vehicle speed and the engine revolution speed, the second displacement adjustment quantity of the variable displacement pump:
wherein nt and nt-1 denote engine revolution speeds at the current moment and a previous moment respectively, k2 denotes a proportionality coefficient, and u denotes the current vehicle speed; and
finally, obtaining a total displacement adjustment quantity by adding the first adjustment quantity and the second adjustment quantity, that is, Δv=Δv1+Δv2, obtaining a relationship between the total displacement adjustment quantity Δv and a control current Δi based on characteristic of the variable displacement pump, that is, Δi=k·Δv, calculating and outputting the control current, and adjusting the displacement of the variable displacement pump.
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