What is Compensator: Definition and 19 Discussions

A motion compensator is a device that decreases the undesirable effects of the relative motion between two connected objects. Motion compensators are usually placed between a floating object and a more stationary object, such as a vessel or a structure fixed to the seabed. The motion compensator does not prevent the motion, but tries to eliminate the negative effects of the movement. These negative effects include (1) the changes in force and stresses, and (2) the hysteresis, i.e., the rapid start-and-stop "jerking" of the objects.
A heave compensator is a kind of motion compensator. Whereas most motion compensators will compensate for movement in all directions, the heave compensator will compensate for movement in only one direction, for instance, for vertical movement. In practice, the words motion compensator and heave compensator are used interchangeably. Sensor technologies being used are inertial sensors and GNSS (example: iMAR Navigation) or image processing.
The simplest motion compensator is the anchor chain of a ship. Not only does the anchor prevent the ship from drifting, but the chain itself dampens the movement of the ship due to undulating motion of the waves. Generally, motion compensators are implemented as springs. For very large forces (dozens to hundreds of tonnes), the springs are implemented as gas springs: hydropneumatic devices — a plunger cylinder buffered by a volume of gas.
Examples of heave compensators include:

Drill string compensators
Riser tensioners
Conductor tensioners
Guideline tensionersMore advanced heave compensated systems are often specified as systems with Passive Heave Compensation or Active Heave Compensation or combinations of these. A new approach to advanced heave compensation systems is offered by Balanced Heave Compensation, increasing safety while lowering energy consumption and spring adjustment times.

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  1. S

    Engineering Problems with Lag Compensator Ogata

    Hello Community, for a School Projekt I must design a lag compensator according to Ogata. Unfortenutely I have some Problems. At first I must find a Value for Kv. I don't know why he use for Kv 5 1/sec in this example. He don't explain why he use 5 and why he use at least 40 degrees. In the...
  2. J

    Identify Condition of lag and lead compensator

    Homework Statement Homework Equations For lag compensator pole is dominating For lead compensator zero is dominating The Attempt at a Solution So for lag compensator: P1 is closer to origin than Z1, so mod of P1 < mod of Z1 So P1 > Z1 (since the poles and zeroes are negative) And for lead...
  3. J

    Lag Compensator Find Value of 'a'

    Homework Statement [/B]Homework Equations I used voltage divider rule. The Attempt at a Solution I get value of a = 3 Book answer is 1.5. Is book wrong or am I wrong?
  4. J

    Compensator Design in system control

    Hello, in my final project for System Control i have been stuck for some time on this following task What i cannot figure out is how to make all these condition work at the same time. When I tried designing a PD controller in sisotool or MATLAB for the i and ii part it worked but i couldn't...
  5. K

    Pressure Compensator Adjustment: 5-35 Bar to 10-70 Bar

    Hello, I was looking on the modular pressure compensator and on the bottom of the page there is: Could anyone explain me why pressure compensator adjustable between 5 and 35 bar corresponds to values between 10 and 70 bar of total ΔP across the valve ? When I bought this valve I thought...
  6. S

    Making a plant stable with a compensator based on given requ

    Homework Statement Homework EquationsThe Attempt at a Solution For the above modeled transfer function of the plant, I'm trying to design a compensator that satisfies some requirements. a. The maximum control bandwidth (0 dB crossover frequency) is 100 rad/s. b. The minimum phase...
  7. ltkach2015

    Alternative Methods vs Iterative Design — Control Theory

    QUESTION (2/2) 1) What are some alternatives to iterative design in control theory? 2) I have a certain plant transfer function PTF(s) that is higher order than two and non-unity numerator. I want certain characteristics such as a certain damping ratio (zeta). So I want approximate it as...
  8. A

    Effect of Phase Lead Compensator on Phase and Gain margins

    Homework Statement What is the effect on the phase and gain margins of a system when a Phase Lead Controller/Compensator is added? Homework Equations I have designed the phase lead controller for the system so if anyone wants to see it, please ask The Attempt at a Solution I know, that in...
  9. A

    Effect of Phase Lead Compensator on Phase and Gain margins

    Homework Statement I was just wondering what was the general effect on phase and gain margins when a phase lead compensator was is added to a system. Homework EquationsThe Attempt at a Solution
  10. Z

    Lead compensator for double integrator

    I'm trying to design a lead compensator for a double integrator plant, which is plant = tf([1],[1 0 0]) I started with the angle condition. So, poles contribute (+) angle and zeros contribute (-) angle and that sums to 180 Desired pole location is 4.4 +- 4.4j So, 45 + 45 = 90 degrees comes...
  11. T

    Compensator for a 6th Order System

    Homework Statement I have a sixth order system with two complex dominant poles shown in the root locus plot attached. This is done using sisotool. I have requirements of 5% overshot and 1.5sec settling time which I have to satisfy. These are shown as border lines with yello shading on the...
  12. D

    How is a Compensator Realized in Practical Control Systems?

    all these things that we learn in control systems...how are they applied in practical situations? for example, we design compensators using bode plot or root locus and we get its transfer function. After that how is the compensator realized??
  13. C

    Lead-Lag Compensator: Band-Pass Filter

    My professor in Feedback Control Systems told me that a lead-lag compensator is basically a low pass filter and that you can't amplify high frequencies because it requires a lot of energy. Thus, you can't design a PID/lead-lag compensated transfer function which acts like a bandpass filter. Is...
  14. M

    Solving Compensator Circuit for Synchronous Buck Converter (SBC)

    Hi All, I'm working on my final year project on synchronous buck converter (SBC). In this project, i have to use an adaptive gate drive (AGD) and a compensator to switch on both of the SBC switches. The AGD is connected to the second switch (Low side switch) of the converter meanwhile for the...
  15. H

    Parameters for Root Locus Method using Lead Compensator

    Hi everyone, I would please like some suggestions regarding where my error is, designing a lead compensator with the root locus method for a unity feedback control system where G = [12.5] / [2.5 1 2500]. I want to set the overshoot zeta = 0.5 for an overshoot of 16%, and settling time Ts =...
  16. A

    Lead/Lag compensator - lead and lag time to pole and zero locations

    Hi, I am having difficulty understanding how to convert pole and zero locations of a lead lag compensator into lead and lag time and vise versa. I have a digital lead and lag compensator which requests: gain, lead time (min) and lag time (min). However i have the gain zeros and poles of...
  17. S

    Neutral Compensator: Learn More About It

    I have learned from some source that there is a device called neutral compensator .Iwould like to know about it in detail.
  18. D

    Thermocouple voltage compensator

    Hey, Anyone know where I might be able to get a thermocouple voltage compensator (an electrical "ice bath" circuit) for cheap or if I may be able to make one? For a T and/or K type thermocouple. I am looking in the range of $30 or less. Here is a description of what I'm talking about. Just...
  19. maverick280857

    Compensator design for non-minimum phase systems

    Hi Given an open loop non-minimum phase transfer function, what in general are the approaches preferable to design a compensator for it? Suppose one is given the location of the desired closed loop poles, is it a standard practice to use complementary root locus (or negative root locus) for...