Shock absorber
A controller of a shock absorber has a differential path configured to perform derivative compensation on the basis of a difference between a target pressure and a detected pressure or on the basis of the detected pressure, multiply the compensated value by a negative gain, and output a resulting value of the multiplication, and obtains an electric current instruction applied to a pressure control solenoid valve.
1. A shock absorber, comprising:
a shock absorber body having
a cylinder,
a reservoir,
a damping passage configured to discharge a liquid from the cylinder to the reservoir, and
a pressure control solenoid valve provided in the damping passage, the pressure control solenoid valve including a valve body and a solenoid;
a pressure sensor configured to detect a pressure upstream of the pressure control solenoid valve; and
a controller configured to control the pressure control solenoid valve by feeding back a detected pressure detected by the pressure sensor, wherein
the controller comprises a differential path configured to
perform derivative compensation on one of the detected pressure, and a difference value between a target pressure and the detected pressure by multiplying one of the detected pressure and the difference value by a negative gain, and
obtain a resulting value of the multiplication and applying the resulting values as an electric current instruction to be applied to the solenoid valve, and
the valve body receives
a first force that is proportional to the pressure upstream of the pressure control solenoid valve, and
a second force generated by the solenoid through which a current, based on the electric current instruction, passes, thereby controlling a flow rate of the liquid discharged in the damping passage.
2. A shock absorber comprising:
a shock absorber body having
a cylinder, a reservoir,
a damping passage configured to discharge a liquid from the cylinder to the reservoir,
a pilot passage provided between the cylinder and the reservoir in parallel with the damping passage,
a pressure control solenoid valve provided in the middle of the pilot passage, the pressure control solenoid valve including a valve body and a solenoid,
a pilot pressure chamber provided in the middle of the pilot passage upstream from the pressure control solenoid valve, and
a damping valve provided in the middle of the damping passage, configured to be biased to a valve closing direction by virtue of a pressure of the pilot pressure chamber, and configured to be biased to a valve opening direction by virtue of a pressure upstream of the damping passage;
a pressure sensor configured to detect a pressure upstream of the pressure control solenoid valve; and
a controller configured to control the pressure control solenoid valve by feeding back a detected pressure detected by the pressure sensor, wherein
the controller comprises a differential path configured to
perform derivative compensation on one of the detected pressure and a difference value between a target pressure and the detected pressure by multiplying one of the detected pressure and the difference value by a negative gain, and
obtain a resulting value of the multiplication and applying the resulting values as an electric current instruction, and
the valve body receives
a first force that is proportional to the pressure upstream of the pressure control solenoid valve, and
a second force generated by the solenoid through which a current, based on the electric current instruction, passes, thereby controlling a flow rate of the liquid discharged in the damping passage.
3. The shock absorber according to claim 1 , wherein the controller comprises an integral path configured to perform integral compensation on the basis of a difference between the target pressure and the detected pressure, and obtains the electric current instruction by adding a value of the integral path and a value of the differential path.
4. The shock absorber according to claim 1 , wherein the pressure control solenoid valve comprises the valve body configured to be biased to a valve opening direction by virtue of the pressure upstream of the pressure control solenoid valve, and
a solenoid configured to exert an actuating force actuating the valve body to a valve closing direction.
5. The shock absorber according to claim 1 , wherein the pressure sensor detects a pressure of the cylinder.
6. The shock absorber according to claim 2 , wherein the controller comprises an integral path configured to perform integral compensation on the basis of a difference between the target pressure and the detected pressure, and obtains the electric current instruction by adding a value of the integral path and a value of the differential path.
7. The shock absorber according to claim 2 , wherein
the pressure control solenoid valve comprises the valve body configured to be biased to a valve opening direction by virtue of the pressure upstream of the pressure control solenoid valve, and
a solenoid configured to exert an actuating force actuating the valve body to a valve closing direction.
8. The shock absorber according to claim 2 , wherein the pressure sensor detects a pressure of the cylinder.