ECE5320 Mechatronics Assignment#01a: Literature Survey on Actuators Topic: Advanced Motion Technologies’ Electromagneti

1. ECE5320 MechatronicsAssignment#01a: Literature Survey on Actuators Topic: Advanced Motion Technologies’Electromagnetic Actuators Prepared by: Cal Coopmans Dept. of Electrical and Computer Engineering Utah State University E: coopmans@gmail.com; T: (435)797-7510; F: (435)797-3054 (ECE Dept.) 3/7/2008

2. Outline • Reference list • To explore further • Major applications (I, II) • Basic working principle • A sample configuration of an ER (I, II) • A sample configuration of an ER – Control (I, II) • Major specifications (I, II, III) • Actuator Spectrum • Basic Dynamics • Limitations • Usage Notes ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

3. Reference list • http://www.yet2.com/app/insight/techofweek/7466 • http://www.advancedmotion.net/products-servoram.asp • http://www.advancedmotion.net/pdf/servo1.pdf • http://www.advancedmotion.net/pdf/veh_sus.pdf • http://www.advancedmotion.net/pdf/servoperformance.pdf ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

4. To explore further • Note that there currently only exists one supplier of Electromagnetic Linear Actuators (Rams) - Advanced Motion Technologies, www.amt.net • http://www.advancedmotion.net/products-overview.asp contains a general overview of the ER products ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

5. Major applications • ERs were originally invented to move Flight Simulators and other simulators • ERs can be used in nearly every situation that a traditional hydraulic actuator can be applied • ERs are completely sealed and can operate in harsh/underwater/sterile environments where hydraulic actuators cannot Picture from: http://www.yet2.com/app/insight/techofweek/7466 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

6. Major Applications II • Stewart Platforms* • Motion Bases • Simulators/training • Active suspension systems • Since ERs don’t require a pump system and interconnects, they can be more directly integrated with control systems • Aircraft launchers for nuclear aircraft *http://en.wikipedia.org/wiki/Stewart_platform ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

7. Basic Working Principal • ERs have been described as “unrolled motors…” re-rolled at 90 degrees • They have a 3-phase interface that is virtually identical to traditional 3-phase servo motors • This means they can be controlled by standard 3-phase motor control hardware Picture from: http://www.advancedmotion.net/pdf/servo1.pdf ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

8. Simplified Diagram of an ER ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

9. Simplified Diagram of an ER II“Double Cup ServoRam” ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

10. Sample Configuration • Attitude control of a moving automobile • Equivalent block for ER: • Suspension Mass (car body) separated from the stator and the ground by the ER’s air spring • A force-sensor combined with active control gives “constant” force during turns and other maneuvers Example from: http://www.advancedmotion.net/pdf/veh_sus.pdf ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

11. Sample Configuration • Attatude clearance control of a automobile • Control loop #1: Magnetic Force ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

12. Sample Configuration II • Ground clearance control of a automobile • Control loop #2: Gas Spring Pressure control ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

13. Sample Configuration - Control • “By using a combination of the active and passive suspension control technologies, it is • also possible to arrange for the power collected by the damping system to be used to • drive the wheel units in fully active mode during the return stroke. This increases the • force holding the wheels in contact with the road and produces a smoother ride.” ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

14. Sample Configuration – Control II ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

15. Major Specifications • There are two main components to the ServoRam design: • The electrical actuator for dynamic loads • The gas (Air) compression for static loads • The ER design has • Speeds up to 80 meters/second • Thrusts of more than 100 metric tons • Strokes more than 100 meters(!) • High efficiency From: http://www.advancedmotion.net/pdf/servoperformance.pdf ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

16. Major Specifications II • A ER has: • Zero mechanical backlash due to a single moving part • Zero transport lag; only mechanical hysteresis • Better than 90% efficient • Scaleable (10N to 1MN) • Better than 1 micron precision • Better than 100m/second rate • More than 100Hz bandwidth • High temperature range (+-200deg C) From: http://www.advancedmotion.net/pdf/servoperformance.pdf ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

17. Major Specifications III • ERs: • Are mess free vs. hydraulics and other mechanical actuators • Have very low wear characteristics • Smooth in action • Nearly silent • Are clean! • Can be used where other actuators cannot ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

18. Actuator Spectrum • From USU Mechatronics Notes: Note that the bandwidth in traditional systems is at the 90 deg phase lag point; and depends on the system dynamics However, ERs have 0 transport lag ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

19. Basic Dynamics • Given an actuator and load system: • Sine Wave Motion: • Differentiate for Velocity • Given Vmax, • 3dB Point: • Now, Inertia: • w/ P Newtons, and Mass M: • Maximum Amplitude: • 6dB Crossover (inertia dominates over input): • So, for a given system: From: http://www.advancedmotion.net/pdf/servoperformance.pdf ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

20. Limitations • Like any electromagnetic machine, the maximum performance is set by the rail voltage to the device vs. the back EMF generated from the operation of the device • However, transport lag (valve opening, pressure spooling, etc.) in hyrdaulic systems limits their maximum frequency and amplitude responses with a hard limit • EMs have a 3dB/decade curve instead ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

21. ER Usage Notes • ERs cannot be substituted directly for hydraulic actuators due to: • Static forces • Dynamic forces • The ER design handles these situations, but in a different way than hydraulics • With proper electromechanical and gas pressure control design, ERs can replace many actuators, while reducing the system complexity ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators