Laser Deflection System: Disturbance Correction Final Presentation Team 5 April 23, 2003 By: Tyler Ferman Matt DiLeo Jack Damerji

Laser Disturbance Correction Goals: movie - movingpantilt.mpeg Goals: movie - movingpantilt.mpeg Correct for a measurable input disturbance. Correct for a measurable input disturbance. Redirect laser to target according to measured disturbance of input trajectory. Redirect laser to target according to measured disturbance of input trajectory. Objectives Objectives Develop accurate controller in order to keep a laser communication link. Develop accurate controller in order to keep a laser communication link. Develop system to measure input trajectory disturbance. Develop system to measure input trajectory disturbance.

Original Specifications Input: Laser Pen Input: Laser Pen Range of motion: 53 o Range of motion: 53 o Location: 5’’ x 6’’ x 0” Location: 5’’ x 6’’ x 0” Assume user input of 0.1 sec to travel across mirror Assume user input of 0.1 sec to travel across mirror Controller: Controller: 5” mirror mounted on center of each axis 5” mirror mounted on center of each axis Range of motion: 35 o Range of motion: 35 o Settling time: ~0.1s Settling time: ~0.1s Overshoot: < 1% Overshoot: < 1% Output: Point on screen Output: Point on screen 36” away 36” away

Original design Constraints First pan-tilt modified to hold a laser pen. First pan-tilt modified to hold a laser pen. cheap and accurate cheap and accurate Narrows input to 2 DOF Narrows input to 2 DOF Second pan-tilt modified to carry a mirror. Second pan-tilt modified to carry a mirror. Challenges Challenges Accurately calculating input Accurately calculating input Positioning Positioning Calculation of desired mirror angles Calculation of desired mirror angles Developing fast and accurate controller Developing fast and accurate controller

Project construction and functional tests Construction: movie - showcase.mpeg Construction: movie - showcase.mpeg Input Pan-Tilt Input Pan-Tilt Controller Pan-Tilt Controller Pan-Tilt Mounting both system on one plate Mounting both system on one plate Friction measurements Friction measurements Tilt: Average Viscous Friction:.002 Coulomb Friction = 0.18 Tilt: Average Viscous Friction:.002 Coulomb Friction = 0.18 Pan: Average Viscous Friction:.0005 Coulomb Friction = 0.08 Pan: Average Viscous Friction:.0005 Coulomb Friction = 0.08

Controller Design Linearizing System Linearizing System Finding a PID compensator Finding a PID compensator Simulating the compensator on nonlinear system Simulating the compensator on nonlinear system

Controller Design Pan Pan Tilt Tilt

Step Response Pan Side

Step Response Tilt Side

Actual Performance Results 1 Hit rate: 100% Avg pan err: Avg tilt err: movie - target.mpeg

Actual Performance Results 2 Hit rate: 99.6% Avg pan err: Avg tilt err: 0.49

Actual Performance Results 3 Hit rate: 85.3% Avg pan err: Avg tilt err:

Actual Performance Results 4 Hit rate: 65.8% Avg pan err: Avg tilt err: movie - crazyfreq.mpeg

Sinusoidal Response Pan side

Sinusoidal Response Tilt side

Comparison of Performance Specification Actual Performance I/P Range of motion 53 o = rad Pan: 54 o = 0.94 rad Tilt: 40 o = 0.70 rad Controller range of motion 35 o = 0.61 rad Pan: 26.4 o = 0.46 rad Tilt: 40.8 o = 0.71 rad Speed 6 rad/s ~ 3rad/s Error 1 cm 1 in Settling time < 0.1s Pan[+,-]: [0.28s, 0.36s] Tilt[+,-]: [0.58s, 0.52s] Percent Overshoot < 1% Pan[+,-]: [0%, 1.5%] Tilt[+,-]: [0%, 0%] Steady State Error < 0.1 o Pan[+,-]: [-0.46, ] Tilt[+,-]: [0.34, 0.57]

System Improvement Max Disturbance without controller 13in on average from each side 13in on average from each sideVS Max Disturbance with controller Max Disturbance with controller 1 in from each side Movie: closeup.mpeg

Success and challenges Success: movie - mirrorview.mpeg Success: movie - mirrorview.mpeg Robust Controller Robust Controller Accurate calculation for desired angles using math model Accurate calculation for desired angles using math model 1300% improvement of disturbance rejection 1300% improvement of disturbance rejection Quick interaction between input pan-tilt and controller pan-tilt Quick interaction between input pan-tilt and controller pan-tilt

Success and challenges Challenges: Challenges: Discrepancy between system model simulation and physical system Discrepancy between system model simulation and physical system Initialization of input and mirror angles Initialization of input and mirror angles Quantization Effects: Quantization Effects: Steady-state error Steady-state error Oscillation due to derivative control Oscillation due to derivative control Design controller for random input (different speeds/frequencies) Design controller for random input (different speeds/frequencies)

Recommendations Adaptive controller to allow control for random input Adaptive controller to allow control for random input Calibration system Calibration system Use Kalman filter to reduce quantization effects Use Kalman filter to reduce quantization effects Recalculate mass matrix, inertia matrix and friction calculation Recalculate mass matrix, inertia matrix and friction calculation

Questions