# Seesaw

## Introduce Dynamics and Control Challenges

The Seesaw module is ideal to introduce intermediate control concepts, involving dynamics and control similar to the inverted pendulum experiment. You can use it to demonstrate real-world control challenges related, for example, to the roll control in aircrafts.

The Seesaw module is used paired with the Linear Servo Base Unit (IP02). With this setup students learn how to:

• obtain a state-space representation of the open-loop system
• design and tune a LQR-based state-feedback controller to balance a seesaw by positioning the linear servo cart
• simulate the system using the designed controller to ensure the system is stabilized
• Implement the controller and evaluate the system’s performance

In addition to teaching intermediate control concepts, Seesaw can be used for research in various areas, including optimal and intelligent control.

## MIMO Configuration to Expand the Scope of the Experiment

Two Seesaw modules can be coupled together using the supplied Seesaw with Pendulum attachment to implement the Multiple-Input Multiple-Output (MIMO) Seesaw Pendulum experiment. In this experiment, one linear servo cart is used to balance both Seesaw modules while the other linear servo cart balances an inverted pendulum.

Seesaw Pendulum Experiment

## How It Works

The Seesaw module consists of two long arms hinged onto a support fulcrum. The system is composed of precisely machined polycarbonate with a durable matte finish. The Seesaw rotates about the pivot axis on an instrumented fulcrum. The rotation axis is coupled to an encoder through a pinion-and-anti-backlash-gear system and is used to measure the Seesaw tilt angle.

A powered cart (Linear Servo Base Unit) is mounted on the seesaw to travel freely along the length of the seesaw. The solid aluminum cart is driven by a rack and pinion mechanism using a 6V DC motor, ensuring consistent and continuous traction. The cart slides along a stainless steel shaft using linear bearings. The cart position is measured using a sensor coupled to the rack via an additional pinion.

## Quanser-developed Courseware Included

The Seesaw and Seesaw Pendulum systems come with Quanser-developed courseware. The Laboratory Guide, together with quick start resources, a comprehensive User Manual, pre-designed controllers and a system model allow you to get your lab running faster, saving months of time typically required to develop lab materials.

• High resolution optical encoder to sense cart position
• High quality aluminum and precision-crafted parts
• Easy-connect cables and connectors
• Pendulum attachment supplied with Seesaw module (pendulum for the Seesaw Pendulum experiment must be purchased separately)
• Fully compatible with MATLAB®/Simulink® and LabVIEW™
• Fully documented system models and parameters provided for MATLAB®, Simulink®, LabVIEW™ and Maple™
• Open architecture design, allowing users to design their own controller
 Dimensions (L x D x H) 112 cm x 20 cm x 40 cm System mass (Seesaw and Linear Servo Base Unit together) 3.6 kg Seesaw geartrain gear ratio 3 Angle range about flat horizontal surface ±11.5 deg Distance from pivot to the Linear Servo Base Unit track 12.5 cm Distance from pivot to COG 5.8 cm Seesaw encoder resolution 0.0015 rad/count

Topics included in the Quanser-developed courseware:

Modeling Topics

• Derivation of dynamic model using Lagrange
• Linearization

Control Topics

• State-space representation
##### The Seesaw and Seesaw Pendulum systems can be also used to teach other topics that are not included in the Quanser-developed courseware.

To set up your Seesaw workstation, you need additional components. Quanser engineers recommend:

 for MATLAB®/Simulink® users for LabVIEW™ users 1x Linear Servo Base Unit 1x Linear Servo Base Unit 1x Q2-USB data acquisition device¹ 1x VoltPAQ-X1 linear voltage amplifier 1x VoltPAQ-X1 linear voltage amplifier Quanser Rapid Control Prototyping toolkit software QUARC real-time control software and one of the following options: - 1x NI myRIO with 1x Quanser Terminal Board for NI myRIO - 1x NI CompactRIO controller² with 1x Quanser Q1-CRIO module - 1x NI M- or X-series data acquisition device³ with 1x Quanser NI Terminal Board

¹ alternatively, you can use Q8-USB, QPIDe or any equivalent NI DAQ device supported by QUARC
² NI cRIO-9074, or NI cRIO-9024 with cRIO-9113 or cRIO-9114 chassis
³ NI DAQ device must be supported by Quanser RCP toolkit. Alternatively, you can use Quanser Q2-USBQ8-USB, or QPIDe

### Other products you might be interested in

Linear Double Inverted Pendulum
Linear Flexible Inverted Pendulum
High Fidelity Linear Cart System
Rotary Inverted Pendulum