Een biofarmaceutisch bedrijf heeft DotX gevraagd om:
- On-site assistance in applying the PID Tuner to tune 4 control loops in two 2000 L Bioreactors.
- On-site Training in PID Tuning using the DotX PID Tuner software.
In this post, we explain how we worked, and the amazing results.
The control challenges
The Bioreactor under consideration is a modern high tech piece of equipment with PID loops for pH, Dissolved Oxygen (DO) and temperature. The most challenging to control is DO. This is due to the fact that DO is controlled by a mix of gasses, including oxygen, CO2, and air. The PID output of the DO loop is the input for a schedule of these gasses.
Analysis of the PID loops
We analysed the control schemes, and data of the last batch. From our analysis, we found:
- All PID control loop tunings could be improved by at least a factor of 2 (in terms of closed-loop response time and damping).
- There was an issue with the schedule of gases used to control DO: at one point, this schedule was causing unstable loop behavior.
- It was useful to add low-pass filters to the DO signal to prevent spikes when applying the D-action in the PID controller.
Result with the DO loop
Below, you see measured data of the DO loop before optimisation (collected in a batch before), and after (collected in the batch after changing the PID settings. Clearly, around t= 75 hours, the deviations from target have reduced by more than a factor 10. This is partly due to the changes in the gas schedule, and the improved PID tuning.
Result with the pH loop
Below, you see measured data of the pH loop before optimisation (collected in a batch before), and after (collected in the batch after changing the PID settings. Clearly, the closed loop response time has improved welll over a factor 4, damping has improved, and the deviations from target have reduced by more than a factor 3.
Een van de Tata-fabrieken bevat 6 kritieke regellussen die de druk regelen. DotX kreeg de opdracht om deze in realtime te monitoren en actie te ondernemen als een of meer lussen prestatievermindering vertoonden, zoals slecht gedempte oscillaties, aandrijfproblemen en verzadiging. DotX heeft een interactieve, intelligente, op het web gebaseerde toepassing gecreëerd die op elk apparaat met internettoegang kan worden uitgevoerd, overal (pc, mobiele telefoon, enz.). De relevante lusgegevens worden elke 5 minuten geüpload naar een Azure-databaseomgeving. Eenmaal daar, worden de gegevens gecontroleerd op de gezondheid van de lus. Een van de controles betreft het ‘volgen van de actuator van de gevraagde positie’. We gebruiken de CUMSUM-methode in combinatie met een model van de reactie van de actuator op de vraag om een probleem te markeren, waarbij we het systeem hebben getraind op een jaar aan gegevens. Zodra de detectie is gemarkeerd, wordt een e-mailwaarschuwing verzonden naar een groep mensen, waaronder DotX. De onderstaande figuur laat zien hoe de toepassing eruitziet op een mobiele telefoon (waarbij het internetadres om veiligheidsredenen is gewijzigd). Het toont de procesvariabele (PV) en het ingestelde punt (SP) gedurende het afgelopen uur.
In the fast-paced digital world we live in today, data centers are the unsung heroes that make it all possible. They're the engines that drive the internet, ensuring that we can connect, work, and play without missing a beat. However, they also consume a significant amount of energy, and the need for more efficient, sustainable solutions has never been more urgent.
Enter Asperitas, a forward-thinking clean-tech company that's leading the charge in greening the data center industry. Since 2014, Asperitas has been on a mission to revolutionize data center technology through their innovative approach: Immersed Computing®.
A Vision of Sustainability
At the heart of Asperitas' mission is a vision of sustainability that's set to redefine the industry. Immersed Computing® technology submerges servers in a specially designed fluid that not only cools them but also offers a range of benefits, from energy efficiency to enhanced performance. It's a true game-changer in the world of data centers, and Asperitas is at the forefront of making this vision a reality.
A Proud Collaboration
At DotX Control Solutions, we're honored to be a part of this journey with Asperitas. Our team has been actively involved in designing and implementing controllers for the Immersed Computing® technology, using Bachmann PLC programming to ensure the seamless and efficient operation of Asperitas' immersed data servers.
Stichting Leeuw asked DotX to develop an optimised version of their hunting-simulator This simulator is a cable driven manipulator that is controlled by an operator. The operator 'teases' prey animals to hunt the manipulator (with meat). DotX has not only developed new optimized control software 'on paper', but also in the form of a game. One of the improvements is the application of 'haptic feedback'. That means, in this case, that the joystick pushes back when the manipulator approaches an obstacle.
The tension forces in the cables are generated by a control algorithm consisting of two parts. The first part calculates the desired tension forces in three perpendicular directions using 3 PID controllers (1 for each direction). These three forces are then processed through a tension distribution algorithm in closed-form as described in . The haptic assistence consists of a push-back force field around fixd objects (like walls and stones in the area) that is scaled on the basis of time to collision, in the direction of the normal vector that is perpendicular to the colliding surface.
 T. Lam et al, “Haptic interface in UAV tele-operation using force-stifness feedback”, 2009, IEEE.Back to Projects
A collaboration between Dotx and researchers throughout the EU
The EU project TESTBED aims at developing innovative solutions for Smart Grids. Smart Grids are new methods of electricity distribution. The current way of electricty distribution consists, roughly speaking, of centralised electicity producers, and decentralised consumers of electricity. However, there is an ever increasing number of decentralised electricity generators, such as wind turbines, solar panels, etcetera. Furthermore, their electricty generation depends on the wheather. The traditional electricty supplier method: just make sure to meet the demand, is inefficient: if there is no demand, one has to get rid of the electricity. The idea of Smart Grids (Smart electricty distribution) is to allow (some of the) consumer appliances to adjust their demand based on the price of electricity. Smart Grids are not yet widespread. However, there are locations where these ideas are likely to be explored soon, such as islands with local electricity networks.
DotX is not likely to actively contribute to Smart Grid research, but instead, we will pick the brains of the researchers involved and try to 'steal' their ideas and convert them into commercial applications. Is that bad? No, this is what the EU and the researchers want us to do!
Stichting Leeuw asked DotX to develop an optimised version of their hunting-simulator. This simulator is a cable driven manipulator that is controlled by an operator. The operator ’teases’ prey animals to hunt the manipulator (with meat).
DotX has not only developed new optimized control software ‘on paper’, but also in the form of a game. One of the improvements is the application of ‘haptic feedback’. That means, in this case, that the joystick pushes back when the manipulator approaches an obstacel. The tension forces in the cables are generated by a control algorithm consisting of two parts. The first part calculates the desired tension forces in three perpendicular directions using 3 PID controllers (1 for each direction). These three forces are then processed through a tension distribution algorithm in closed-form as described in .
The haptic assistance consists of a push-back force field around fixed objects (like walls and stones in the area) that is scaled on the basis of time to collision, in the direction of the normal vector that is perpendicular to the colliding surface.
 T. Lam et al, “Haptic interface in UAV tele-operation using force-stifness feedback”, 2009, IEEE.
The Camera Measurement System (CMS) is a high-resolution vision system built in coorperation with Tebulo (www.tebulo.com). CMS can accurately measure the 3D coordinates of both small and large objects.
The CMS system uses a laser (number 2) to project a line (3) on an object (here: the tennis ball). It then makes a photo with its camera (1).
The CMS software then detects the laser light projection points and computes the exact coordinates of these points. Subsequently, this information is processed further into relevant data. For instance, in case of a tennis ball, CMS can measure its diameter.
Applications of the CMS system include:
- The measurement of a steel coil’s centre of gravity location
- Determination of the amount of loose wraps on steel coils
- Telescoping (sizes)
- Strip thickness
- Strip profile
- Accuracy: +/- 0.5 mm
- Measurement distances from CMS to object: 0.01 – 5.00 m
- Software: coded in C++ Communication with external hardware: Ethernet and Profibus
A tailor made controller has been developed for the control of two pumpstations in the polder 'Waterlandse Boezem'. The controller had to satisfy complicated on/off requirements, and had to minimise pumping activity in the more expensive day-hours. A paper on this subject has been published, and can be downloaded in our Paper section. Movie on this subject:The movie shows iterations of the controller while finding the optimal pump settings to maintain the water level (lowest graph) within the limits (dashed lines). The upper graph shows the predicted "load" on the polder (i.e. the expected inflow of water in the next 24 hours).