Five-Bar

I worked on this project on my second year of my bachelor studies, the aim was to create a Graphical User Interface in Matlab and integrate the Virtual Reality simulation of a 2DOF mechanism. It was my first time using Matlab for this purpose and I faced several problems: how to import a Solidwork model of the mechanism, how to exchange data between the GUI and simulink model, and how to visualize the VR in the GUI.

The implementation went faster than planned, so I decided to build the real system too. I used stepper motors as actuators with 0.39° angular step by using gear reduction and half step control. The motors were not so powerful, so the links were made of aluminium. I commanded the motores through the parallel port of the PC, sending 8 bits. I build a driver circuit to safely control the motors by separating the control signal from the power supply with photocouplers.

Publication: Előd Páll, Design and real-time control of 2DOF mechanism in Virtual Reality with Matlab Graphical User Interface, ACTA TECHNICA NAPOCENSIS, Cluj-Napoca, May 2011

Abstract: Designing a control system is easier for simulated model rather than for the real system. The simulation can be implemented and visualized in the control software of an automated system. Hence, it makes easier to test and observe the behavior of the system. The simulation can be realistic if all the physical aspects are set. This is the reason to create a User Interface which controls a five bar mechanism and to simulate in real time the behavior of the mechanism. The chosen program is Matlab which has the features for this task.

Keywords: graphical interface, Matlab GUIDE, five-bar, virtual reality, simulation, real-time control.

Full document.

The circuit for parallel connection:

  • parallel port

  • resistances

  • photo couplers

  • transistors

  • LEDs

The five-bar mechanism:

  • aluminium bars

  • two stepper motors

    • angular displacement 3,91º gear reduction 12/60

    • half step & reduction 0.391º

Graphical User Interface:

Matlab GUI communicates on parallel port with the mechanism.

  • Direct & Inverse control

  • Simulation

  • Virtual Reality