Controlling Speed Mechanically Engr 315 Control Systems Calvin College 8 December 2004 Brian Katerberg Andy Vander Moren

The Original Governor James Watt’s Flyball Governor Used to prevent steam engines from overheating while responding to the applied loads.

Modern Governor

Electrical Speed Controls Tachometer Tachometer Automotive Cruise Control Automotive Cruise Control Andy Wallner’s Presentation Yesterday Andy Wallner’s Presentation Yesterday

Why Use an Electronic Governor? Allows for very precise governing Allows for very precise governing Requires very limited amount of moving parts Requires very limited amount of moving parts Can fit in small areas Can fit in small areas Easy to adjust for changes in application Easy to adjust for changes in application Interfaces easily with other controlling devices Interfaces easily with other controlling devices

Why Use a Mechanical Governor? Could be less expensive Could be less expensive Can use in wide range of conditions Can use in wide range of conditions Marine Applications Marine Applications Extreme Temperatures Extreme Temperatures Usually easier to troubleshoot Usually easier to troubleshoot More transparent More transparent

Mechanical Governor Shortcomings Have a delayed response time called “droop” Have a delayed response time called “droop” This delay in response time induces something called “hunting” This delay in response time induces something called “hunting” Can be thought of in terms of overshoot and over/under damping Can be thought of in terms of overshoot and over/under damping Can tune a mechanical system to minimize hunting using additional external mechanical governors Can tune a mechanical system to minimize hunting using additional external mechanical governors

Simple MatLAB Simulation

Relation to Our Senior Design Project We are building a winnowing machine for use in Kenya We are building a winnowing machine for use in Kenya Need some sort of governing device to control the speed of our fan Need some sort of governing device to control the speed of our fan Device must be simple, easy to use, and low cost Device must be simple, easy to use, and low cost Kenyan’s background should be taken into account especially for repairs Kenyan’s background should be taken into account especially for repairs Not much electrical experience Not much electrical experience Bikes are major form of transportation Bikes are major form of transportation

Governors…in Bikes? Di2 (Digitally Integrated Intelligence) Automatic Derailleur There Can Be!

Maximum Air Speed

Stability Graph

Questions? MechanicalGovernor A Governor on a Bike