Triaxial Experiment Instrument Control System Design And Realization

Soil triaxial apparatus is used to simulate bearing load of soil in the ground. Triaxial compression test is a method of determining shear strength of soil using soil triaxial apparatus. Because shear strength directly reflects the capacity of soil bearing load, the shear strength in the accuracy closely relates to the stability of the building foundation. The test precision has been unable to meet the increasing demand due to the late start of domestic industry of testing machine, the low degree of automation and the complex operation.According to the principle of determining shear strength of soil, the structure design of apparatus and test methods are introduced in the paper. Because of the experiment needs, a control system is designed to control soil triaxial apparatus finishing test. The automation and accuracy of test is improved, and more accurate data is accessed to calculate the shear strength. Because the large span of soil loading is a complex nonlinear control process, in which parameters of traditional PID control are fixed, the adaptive capacity of control system is poor. The varying parameters PID algorithm is employed in the control system. Based on Particle Swarm Optimizer (PSO) algorithm, its parameters are self-tuned to improve the adaptive ability of control system.DSP is the core of hardware design of control system. The implementing agency of control is an AC servo system. The feedback channel is composed of the measurement amplifier and 16-bit A / D converter. The self-tuning PID control is the core of software design of control system. Feasibility and validity of the control system are proved in the stress path test. Finally, the use of the control system is introduced, and the design of it is analysed.