Research on Embedded Controller of Hydraulic Vibrating Table Based on
DSP
Authors: Zhang Bing , Huang Hua , Tang Shaodong , Cai Jiamin , Zhu Fangzheng 
Published: April 2021

Background:

The vibration control loop is the key technology adopt to improve the
control performance of the vibration table, which is set outside of the hydraulic vibration table
servo control loop. However, the huge number of signal processing work prompts high demands
on the calculation ability of the vibration controller. One kind of multi-CPU embedded vibration
controller constructed by Digital Signal Processor (DSP) is proposed considering the working
principle of 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
unit distributes vibration control tasks to the different processing unit to realize distributed algorithm
calculations. Every processing unit uses dual-port memory to accomplish data interaction
between each other. The development of the embedded controller provides a benchmark engineering
case for the design of the hydraulic vibration table vibration controller.

Objective:

This article focuses on the development of the multi-CPU embedded vibration controller
and the distributed calculations. Meanwhile, the power spectrum density experiment is carried
out 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, two
closed-loop controls. The bandwidth of the system is further broadened by the vibration control of
the outer loop. Besides, the accuracy of vibration control is also improved. Then, the development
needs of the vibration controller are put forward according to the detailed process of the power
spectrum density replication. 2) An arithmetic processing unit is formed by using TI C2000 series
DSP to calculate a large number of signal processing and a signal acquisition unit at high speed. In
order to improve signal processing efficiency, the signal acquisition unit is used to perform preprocessing
calculations (data acquisition and filtering) and vibration control calculations in a distributed
manner. 3) Processing speed is further improved by taking full advantage of DSP software
sources include lots of library functions and optimized assembly library functions. 4) The friendly
operation of the controller and the safety monitoring of the experiment process are realized by the
industrial computer served as the human-computer interaction unit. 5) Multi-CPU data sharing is
achieved through using dual-port RAM to realize.

Results:

Through experiments, the developed embedded controller is fully estimated. The experiment
shows that the developed hydraulic vibration table can realize real-time vibration control.
Concerning the acceleration power spectrum density reproduction experiment, 256 acceleration
response samples are calculated, and the update time is 4ms. The tracking accuracy of the timedomain
waveform is controlled within 0.3%.

Conclusion:

The use of the developed embedded controller with signal conditioning equipment
can achieve real-time control of the hydraulic vibration table, but the performance of the embedded
controller can be promoted in advance, and the performance improvement of the hydraulic vibration
table embedded controller can be studied from the following aspects:
1) The Fourier calculation is executed by the acquisition unit to share the calculation workload of
the 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 embedded
controller with superior performance instead of an industrial computer to reduce the size, improve
the performance; 4) The DSP real-time operating system should be used, and the task
scheduling of vibration control experiments should be optimized.