1. Ⅰ、Brief introduction to the paper
Ⅱ、Authors’ information
Ⅲ、Project based on the foundation

2. Ⅰ、Brief introduction to the paper

3. Research source、purpose and significance
Source: National Natural Science Foundation of China (Grant No )
Purpose: Achieve relatively consistent dynamic pressure control performance across the scope of work (2–140 kPa)
Significance: Meet the demand of dynamic pressure signal generation in the application of the hardware-in-the-loop simulation of aerospace engineering

4. Research status
In the past decades, a great interest has been shown in pneumatic position servo systems. Compared with that of position servo controls, research on the design of pressure controllers at present is quite limited.
At present, the researches on pneumatic pressure control mainly focus on constant pressure regulation. Poor dynamic characteristics and strong nonlinearity of such systems limit its application in the field of pressure tracking control.
PID controller and fuzzy controller have been widely used in nonlinear system.

5. Research contents System description and analysis
Design of fuzzy PID controller with asymmetric fuzzy compensator
Experimental verification

6. Open-loop system step responses from simulation and experiment
System description and analysis
The system uses a compressor and a vacuum pump as positive and negative pressure source. Computer gets pressure signal measured by a pressure sensor and outputs command to an EPPCV, which controls airflow rate and process of chamber charging and discharging.
The mathematical model of the system is not very accurate.
There exists the asymmetry during charging and discharging processes, especially in the range of lower pressure.
Principle sketch of PNPPSS
Configuration of the exoskeleton arm system
Open-loop system step responses from simulation and experiment

7. Structure of fuzzy PID controller with asymmetric fuzzy compensator
Design of fuzzy PID controller with asymmetric fuzzy compensator
Because of the difficulty to obtain the accurate mathematic model, PID controller with a fuzzy inference module is proposed
Because of the wide range of pressure and serious asymmetry of charging and discharging process, an asymmetric compensator using the current pressure p and output uf of the fuzzy PID controller as inputs is designed
Structure of fuzzy PID controller with
asymmetric fuzzy compensator

8. Fuzzy rules for the fuzzy PID controller
Fuzzy rules for the asymmetric fuzzy compensator
KP/KI/KD E NB NM NS ZE PS PM PB EC
BB/
SS/ SM
BM/
SM/ MM
MM/ SS
MM/MM/ BB BM
MM/MM
MM/MM/MM
MM/MM/BM
MM/BM
BM/MM Uf P ZE SS SM MM BB VB NB BM VS NS PS PB
Membership functions for p, uf and λ

9. Experimental verification
Proposed controller has better performance than PID controller, especially in the condition of lower pressure.
Sinusoid and square wave tracing experimental results with PID and proposed controller

10. Comparison experimental results show that the control performance with the proposed controller is better and relatively stable at different setting pressure
The asymmetry of charging and discharging rate can be compensated by the fuzzy compensator
The phase and amplitude errors tracking sinusoid
Experimental results with fuzzy PID and proposed controller
Average value p / kPa
Phase error θe / (°)
Amplitude error Ae / %
Proposed controller
Fuzzy PID
PID
140
6.2
8.6
3.9
2.4
6.7
7.6 20
6.4
17.9
13.7
2.7
10.7
22.8 5
7.9
36.4
28.9
4.6
3.8
32.6 2
8.1
45.8
42.0
4.7
7.4
38.7
The output of asymmetric fuzzy compensator

11. Ⅱ、Authors’ information

12. Yang Gang
Assistant Professor, HUST，China
Research interest:
Electro-pneumatic control system; High-pressure pneumatic component and system; Intelligent control.
Tel: ;
Li Baoren
Professor, HUST，China
Research interest:
Electro-pneumatic control component and system; Hydraulic control system; System synthesis for mechatronic equipment.
Du Jingmin
Assistant Professor , HUST，China
Research interest:
Pneumatics
Intelligent control
Tel:
Fu Xiaoyun
Assistant Professor, HUST，China
Research interest:
Nonlinear control of dynamic systems; Electro-pneumatic control component and system; System synthesis for mechatronic equipment.

13. Research areas
FESTO Pneumatic Center is organized into the following areas:
Intelligent hydraulic/ pneumatic components
Electro-hydraulic/ pneumatic servo system
High-pressure pneumatic technology
Mechatronics/ hydraulic/ pneumatic intelligent control
Autonomous Control Technology of underwater vehicle
Hardware in the loop simulation technology of aircraft

14. Honor/ awards
The First High Education Award for Science and Technology Progress, 2009
The Second National Award for Science and Technology Progress, 2003

15. Ⅲ 、Project based on the foundation

16. Project: FADS dynamic simulation test equipment
Technical basis: Positive and negative pneumatic pressure servo technology
Function: Simulate atmospheric pressure parameter and measure atmospheric pressure parameter