Earthquake Disturbance Control System

1
Earthquake Disturbance Control System

• David Allen
• Kevin Caldwell
• Brian Chaney
• Juan Juarez

2
The Nature of an Earthquake

• Horizontal, sinusoidal movement.
• Civil Engineers use Gs to measure the force of
  an earthquake.
• We are more familiar with the Richter scale.

3
Earthquake Disturbance

• Acceleration causes the most discomfort.
• Excessive acceleration may cause damage to the
  building.
• Building is saved through the use of the right
  building materials, not just the disturbance
  control system.

4
Types of Earthquake Disturbance Control Systems

• Building on rollers.
• Semi-active control utilizing dampers.
• Active control system utilizing a large mass
  placed at the top of the building.

5
Our Design

• Active control system utilizing a large mass
  placed at the top of the building.
• This mass is around 1 of the total mass of the
  building.
• The mass is placed on rollers and attached to the
  building with springs and dampers.
• Hydraulics are used to move this mass to help
  negate the movement of the building.

6
Our Design
Simulates Earthquake
7
Free Body Diagram for the Block

• mmxm - cdxb cdxm - ksxb ksxm -mmxg Fh

Fs
Fs
Fh
Fd
Fd
8
Free Body Diagram for the Building

• mbxb (ce cd)xb - cdxm (ke ks)xb - ksxm
  -ßbmbxg - Fh

Fh
Fs
Fs
Fd
Fd
Fe
9
Kobori's Control Law

• u gbxb - gmxm
• For stability gb gm g

10
Our system with Kobori's Law

• mbxb'' (ce cd g)xb' - (cd g)xm (ke
  ks)xb -ksxm -ßbmbxg''
• mmxm'' - (cd g)xb' (cd g)xm - ksxb ksxm
  -mmxg''

11
Characteristic Equation

• a4S4 a3S3 a2S2 a1S a0 0
• a4 mbmm
• a3 mbcd mbg mmce mmcd mmg
• a2 mbks mmke mmks cecd ceg
• a1 kecd keg ksce
• a0 keks

12
Routh-Hurwitz Criterion

• a0 , a1 , a2 , a3 , a4 gt 0
• a2a3 - a1a4 gt 0
• a1a2a3 - a12a4 - a0a32 gt 0
• g gt 0

13
Stability

• Bode Plot Root - Locus

14
3D Simulation

• Skyscraper with earthquake disturbance

15
Our system in action...

• Skyscraper with implementation of active mass
  control system