Abstract:
The swing-up control of a Rotary Double Inverted Pendulum (RDIP) is considered
one of the benchmark problems in teaching advanced control systems engineering.
The RDIP is a 4th-order nonlinear underactuated system that involves many coupled
forces affecting the system’s stability. Fabrication of a reliable RDIP system
requires precision machining and high-quality electronic sensors, and the few readily
available products on the market are prohibitively expensive. With the current
number of student enrollments in engineering faculties at state universities in Sri
Lanka, multiple units of such systems are required to improve student interaction
and hands-on experience. Therefore, a virtual environment for simulating and
testing such systems could improve the current status of engineering education in
Sri Lanka. In this study, a virtual environment has been developed for studying
the swing-up behavior of the rotary double inverted pendulum. The developed
virtual system is based on commonly available software in engineering education.
The state-space mathematical model of the system was built using the Lagrangian
method. Computer-Aided Design was used to demonstrate the dynamic system
behavior visually, which was integrated with real-world conditions such as gravity,
friction, and joint damping. The swing-up is achieved using multi-stage energy
control. Energy is pumped into the system sequentially, considering the energy
levels of the two links separately until the target energy level is achieved. Overall,
this virtual environment allows multiple users to engage in individual learning
of control systems engineering at once, even without depending on an internet
connection. Furthermore, deploying a virtual RDIP will completely eliminate expensive
hardware failures due to student mistakes.
