| Abstrakt: |
Background: The vibration control loop is the key technology adopt to improve thecontrol performance of the vibration table, which is set outside of the hydraulic vibration table servocontrol loop. However, the huge number of signal processing work prompts high demands onthe calculation ability of the vibration controller. One kind of multi-CPU embedded vibration controllerconstructed by Digital Signal Processor (DSP) is proposed considering the working principleof the hydraulic vibration table and the Power Spectrum Density (PSD) reproduction process.The embedded controller consists of an acquisition unit, a calculation unit, and a monitoring unitdistributes vibration control tasks to the different processing unit to realize distributed algorithmcalculations. Every processing unit uses dual-port memory to accomplish data interaction betweeneach other. The development of the embedded controller provides a benchmark engineering casefor the design of the hydraulic vibration table vibration controller. Objective: This article focuses on the development of the multi-CPU embedded vibration controllerand the distributed calculations. Meanwhile, the power spectrum density experiment is carriedout to verify the performance of the hydraulic vibration embedded controller. Methods: 1) The structure of the hydraulic vibration table control system is given, that is, twoclosed-loop controls. The bandwidth of the system is further broadened by the vibration control ofthe outer loop. Besides, the accuracy of vibration control is also improved. Then, the developmentneeds of the vibration controller are put forward according to the detailed process of the powerspectrum density replication. 2) An arithmetic processing unit is formed by using TI C2000 seriesDSP to calculate a large number of signal processing and a signal acquisition unit at high speed. Inorder to improve signal processing efficiency, the signal acquisition unit is used to perform preprocessingcalculations (data acquisition and filtering) and vibration control calculations in a distributedmanner. 3) Processing speed is further improved by taking full advantage of DSP softwaresources include lots of library functions and optimized assembly library functions. 4) The friendlyoperation of the controller and the safety monitoring of the experiment process are realized by theindustrial computer served as the human-computer interaction unit. 5) Multi-CPU data sharing isachieved through using dual-port RAM to realize. Results: Through experiments, the developed embedded controller is fully estimated. The experimentshows that the developed hydraulic vibration table can realize real-time vibration control.Concerning the acceleration power spectrum density reproduction experiment, 256 acceleration responsesamples are calculated, and the update time is 4ms. The tracking accuracy of the timedomainwaveform is controlled within 0.3%. Conclusion: The use of the developed embedded controller with signal conditioning equipmentcan achieve real-time control of the hydraulic vibration table, but the performance of the embeddedcontroller can be promoted in advance, and the performance improvement of the hydraulic vibrationtable embedded controller can be studied from the following aspects: 1) The Fourier calculation is executed by the acquisition unit to share the calculation workload ofthe calculation unit; 2) The computing unit uses a signal processor chip with better performance,although this will bring development difficulties; 3) The monitoring computer can use an embeddedcontroller with superior performance instead of an industrial computer to reduce the size, improvethe performance; 4) The DSP real-time operating system should be used, and the task schedulingof vibration control experiments should be optimized. |
