Digital Control Lab

1. MAGNETIC LEVITATION

MagLev apparatus dramatically demonstrates closed loop levitation of permanent and ferromagnetic elements. The apparatus includes laser feedback and high flux magnetics to affect large displacements and provide visually stimulating tracking and regulation demonstrations.

The system is quickly set up in the open loop stable and unstable (repulsive and attractive fields) configurations. By adding a second magnet and driving both actuators, MIMO control is studied.

The inherent magnetic field nonlinearities may be inverted via provided real-time algorithms for linear control study or the full system dynamics may be examined.

Disturbances may be introduced via the second drive coil for demonstrating system regulation in SISO operation. An optional turn table accessory provides graphic demonstration of induced field levitation - the principal used in high speed bullet trains.







2. RECTILINEAR PLANT

This classical system appears commonly in dynamics and controls text books and serves as a benchmark for control method evaluation. This system provides vivid demonstrations of elementary topics such as rigid body PID control, lead/lag compensators, phase and gain margin, trajectory tracking, and regulation - as well as advanced high order collocated and noncollocated system control. The apparatus also clearly demonstrates salient properties of flexible systems such as mode shapes, natural frequencies, and characteristic transient and frequency responses. An optional secondary drive may be positioned at any output (mass carriage) to create a MIMO plant and provide for the study of disturbance rejection. Study of this system provides the first steps in understanding parameter estimation and system identification occuring in large plants.







3. TWIN ROTOR MULTIPLE INPUT MULTIPLE OUTPUT (TRMS) MODEL

The TRMS workshop serves as a model of a helicopter. However some significant simplifications are made. First is the fact that TRMS is attached to a tower and second that the helicopter position and velocity is controlled through the rotor velocity vasriation. In the real helicopter the rotor velocity is not constant and the propulsion is varied through the rotor blades angle modification.

Nevertheless the most important dynamic characteristics present in a helicopter are captured in the TRMS model. like in a real helicopter there is a significant cross coupling between two rotors. If we activate the vertical position rotor the helicopter will also turn in the horizontal plane.

With two inputs (the voltages supplied to the rotors) and outputs (vertical and horizontal angles and angular velocities) the TRMS is an excellent MIMO plant for getting started with a helicopter!







4. PIC MICROCONTROLLER

PIC is a family of modified Harvard architecture microcontrollers made by Microchip Technology, derived from the PIC 1650 originally developed by General Instrument's Microelectronics Division. The name PIC initially referred to "Peripheral Interface Controller". PIC's are popular with both industrial developers and hobbyists alike due to their low cost, large user base, extensive collection of application notes, availability of low cost or free development tools, and serial programming capability.

These PICs are programmed using MATRIX MULTIMEDIAs E-blocks circuit board. E-blocks are small circuit boards each of which contains a block electronics that one would typically find in an electronic or embedded system. There are many circuit boards in the range; from simple LED boards to more complex boards like device programmers, Bluetooth, TCP/IP and many more. These blocks can be snapped together to form a wide variety of systems that can be used for learning electronics and for the rapid prototyping of complex electronic system.







5. GYROSCOPE

ECP's four axis Control Moment Gyroscope is a dynamically rich system that provides superb demonstrations of multi-DOF rigid body control. Elementary experiments that graphically show the phenomenon of gyroscopic torque and its use in precision high authority control are readily performed. More advanced topics range from MIMO linear control to fully general nonlinear control with singularity avoidance. Thus the system yields demonstrations that are intriguing to the layman and post-doctorate alike! In addition, the plant may be used to emulate the control of satellite attitude. The apparatus includes low friction slip rings at all gimbals for unlimited range of motion, and precision encoders for feedback of all position and velocity states. A host of safety features such as fail-safe brakes, inertial rate sensing switches, and real-time watch-dog monitoring provide for safe operation of the apparatus.







6. INVERTED PENDULUM

This unique ECP design vividly demonstrates the need for and effectiveness of closed loop control. It is not the conventional rod-on-cart inverted pendulum, but rather, it steers a horizontal balancing rod in the presence of gravity to control the vertical pendulum rod. The plant has both right half plane poles and zeros as well as kinematic and gravitationally coupled nonlinearities. By adjusting mass properties, these roots may be varied to make the control problem range from being relatively simple to theoretically impossible! The system includes removable and adjustable moment arm counterweights on the vertical and horizontal rods for quick adjustment of the plant dynamics. It features linear and rotary ball bearings at the joints for low friction and consistent dynamic properties.