Ball And Beam System

IACSIT International Journal of Engineering and Technology, Vol.2, No.4, August 2010 ISSN: 1793-8236

Application of a LabVIEW for Real-Time Control of Ball and Beam System
Basil Hamed
Abstract—Virtual instrumentation is defined as the combination of measurement and control hardware and application software with industry-standard computer technology to create user-defined instrumentationsystems. This paper presents a real-time application of Ball and Beam controlled by PID controller designed based on LabVIEW program and the real - time position control of the DC motor was realized by using DAQ device. Ball and Beam is a common feedback control system application, due mostly to its ease in construction and its use in learning. Using Labview makes the application very useful forteaching and training students in data conversion domain. The system includes a ball, a beam, a motor and several sensors. The basic idea is to use the torque generated from a motor to control the position of the ball on the beam. The mathematical model for this system is inherently nonlinear, so linearization was done in order to improve the controllability of the system. Data acquisition, signalprocessing and analyzing can be completed by virtual instrument based on LabVIEW. Index Terms—Ball and Beam, proportional–integralderivative (PID), Data Acquisition Card, Lab View.

Digital Controller
1. 2. 3. 4. More expensive. Flexibility in response to design changes. Noise immunity. More accuracy.

Analog Controller
1. Less expensive. 2. More complex to build. 3. More sensitive for noise. 4.Less accuracy.

TABLE (1): ADVANTAGES AND DISADVANTAGES; OF ANALOG AND DIGITAL CONTROLLERS.

I.

INTRODUCTION

Closed loop control systems classified for two types of control, analog and digital. Analog and digital control have a relation between each other that can convert analog to digital and vice versa which gives the control world more flexibility for controlling any device. Figure 1show the cycle of converting analog signal to digital signal and applying digital signal to computer then converting the digital signal back to analog signal.

The Ball and Beam is a common feedback control system, due mostly to its ease in construction, and its use in learning for applying control to stabilize an unstable system. This system is extremely unstable and needs compensation tostabilize. The ball moves freely along the length of the beam. Sensors are placed on one side of the beam to detect the position of the ball. An actuator must drive the beam to a desired angle, either by applying a torque at the center, or in our case, a force at one of the ends. The physical hardware of the system is simple, a steel ball rolling on the top of a long wooden beam. The beam is mountedon the output shaft of an electrical motor and so the beam can be tilted about its center axis by applying an electrical control signal to the motor amplifier. The position of the ball on the beam can be measured using a special sensor; Figure 2 shows the simple diagram for ball and beam. When the angle is changed from the horizontal position, gravity causes the ball to roll along the beam. Theobjective of this paper is to design a digital PID controller using LabVIEW, and DAQ 6024E for this system so that the ball's position can be manipulated.

Figure (1): Cycle of analog and digital signal

Nowadays most of the applications which need more accuracy are controlled by digital control. Table (1) shows the advantages and disadvantages of the analog and digital control

Figure (2):Ball and beam System

II.

DYNAMIC MODEL

Basil Hamed is with theElectrical Engineering Department, Islamic University of Gaza, P.O.BOX 108, Gaza, Palestine(email: bhamed@iugaza.edu).

Physical systems are modeled and manipulated in software, and realized in hardware to demonstrate what differences may occur with real-life applications. By solving control problems using software-based...