Physics:Camcon binary actuator
The Camcon binary actuator is an electronically-controlled electromagnetic actuation device that physically moves in between 2 stable states. Unlike a solenoid the binary actuator technology (BAT) only uses energy when switching in between states. It does not require a constant current running through it.
Design and operation
The binary actuator consists of an electromagnet that polarizes a rod resting in between 2 magnetic poles that are situated by one end of the rod. The charge on the rod then experiences attraction to one pole or another, causing the end of the rod to attach to one of the two poles of the magnetic circuit. When one end of the rod moves to one magnetic pole, the rod pivots on its midpoint and the other end of the rod moves in the opposite direction. This movement can be used to control a valve sealing or opening a passage.
This design is bistable, meaning it will remain in either position until prompted to adopt its other stable state via the process as described above. The end of the rod will always remain in contact with one pole or the other, even when there is no current flowing through the system. Part of the force of attraction is stored in springs while the rod remains in either position to aid in accelerating the rod towards its other position when the magnetic flux is reversed. This conserves energy whenever the magnetic field switches, in turn using less energy to switch into either position. This makes the Binary actuator energy efficient
Forces involved
The following formula can be used to compute forces and moments:
Fp= Φ2 P/4
Where Fp [ N] = pressure force, Φ [mm] is orifice diameter, and P[ bar] is the pressure difference at inlet
Δ F= Fh-Fp
Where Fh [ N] is the holding force and Fp [ N] is the pressure force
Fs= Fh/cos a
Where Fs [ N] is the spring force, Fh [ N] is the holding force, and a [deg] =Spring declination angle
Fr= Fh tan(a)
Where Fr [ N] is the rotating force, Fh [ N] is holding force and a [deg] .= Spring declination angle
Ms=Fr (r-K)cos c
Where Ms [Nm] is reversing momentum that is caused by spring force, Fr [ N] is the rotating force, K [mm] = the spring fitting offset, and c [deg] is the pivoting force projection angle
Mp=Δ F Φ/2
Where Mp [Nm]-reversing momentum caused by pressure and Φ [mm] is the orifice diameter
Mr=Ms+Mp
Where Mr [Nm] = effective reversing momentum, Ms [Nm] is reversing momentum that is caused by spring force, and Mp [Nm]-reversing momentum caused by pressure and Φ [mm] is the orifice diameter
Mh=Fm L
Where Mh [Nm] is the holding momentum, Fm [N]=magnetic force, and L [mm] is the Swing bar’s effective length
And In order to maintain the valve in a closed state Fh must be greater than Fp.
History
The Camcon binary actuator was developed by Wladyslaw Wygnanski. The developmental principle of BAT was an internal energy recycling concept which was first applied to generate a fast responding pneumatic horn valve[2] with high energy efficiency for an air powered sound source loudspeaker. Subsequently, Wygnanski developed a series of inventions in the patent class, “permanent or constantly energized magnet actuator”. By the late 1990s, he made a conscious decision to refocus the development of BAT and joined with Camcon in further development of the technology.[2]
Application of Camcon binary actuation
While the technology was originally proposed for use in reducing noise in the aircraft industry, or to control liquid nitrogen flow in spacecraft from NASA, Camcon took the technology of the binary actuator as a means to control flow of fluid and gases in oil and gas industries, Automotive industry , and more recently in healthcare.[2]
Oil and gas industries
Control of Gas Lift Technique(way of moving oil to surface by pumping gas bubbles into drill lines) electronically and efficiently rather than manual machine intervention.
Automotive industries
Used in anti-locking brake systems for trucks, parking brakes, and digitally driven engine valves.[3][2]
A series of patents assigned to Camcon such as the 2005 patent for "Electromagnetic fluid flow control valve"[1] using the binary actuator technology have been used in the automotive industry.
Health care
Recently Camcom have used BAT in the health care industry to provide a precise and accurate method of delivery of oxygen to a patient. It would be used to shut off or regulate oxygen flow using a series of valves. Additional areas where Camcon has disclosed BAT may be applied in healthcare include implantable devices within the human body, mechanical aids, such as prosthetics and blood circulation support and accurate laboratory dispensing equipment, which can also be applied to drug dosing and delivery.[4][2]
Alternate applications of binary actuation
Another application is in robotics. The design of these systems, while they still use the same principle (having 2 home states), are vastly different and are unrelated to the Camcon binary actuation technology. Binary robotics devices are capable of executing practical tasks, such as instrument placement for planetary exploration. Robotics are envisioned to use Binary actuators as they are smaller and less complex than conventional servos and better suited, for example, for legged locomotion through rough terrain.[5] One such extension of the binary actuator is the dielectric Elastomer actuation (DEA). The DEA is an application of binary actuation described by Jean-Sebastien Plante and Steven Dubowsky.[6][7] One of their applications uses the binary principle of flipping between the two stable states, but using a diamond shaped frame instead of a rocking rod. Elastic bands store energy similar to the springs of the BAT design.[8]
Another application of the principles used by BAT is in articulated binary elements[9] (ABEs), One such design consists of bi-stable mechanisms sandwiched by flexible beams. The actuators can be mounted surrounding a joint in a similar fashion to the muscles in the human elbow or knee. Experimental prototype binary devices and elements have been designed and constructed. The Binary Robotic Articulated Intelligent Device[9][7] (BRAID) and a design of a six legged walking robot capable of walking in rough terrain are examples.
Patents
- Sound pressure active transformer, (1983).[10]
- Electromagnetic actuators, (1989).[11]
- Improved electro-magnetically operable device, (2004).[12]
- Improved actuator requiring low power for actuation for remotely located valve operation and valve actuator combination, (2007).[13]
- Electromagnetic fluid flow control valve, (2007).[1]
- Rotary electromagnetic actuator, (2017).[14]
See also
Kinetic energy recovery system
References
- ↑ 1.0 1.1 1.2 Wygnanski, Wladyslaw, "Electromagnetic fluid flow control valve", US patent 7252114, published 2007-08-07, assigned to Camcon Ltd.
- ↑ 2.0 2.1 2.2 2.3 2.4 "Camcon Medical | The heritage of Binary Actuation Technology" (in en-GB). 2018-11-30. https://camcon-medical.com/the-heritage-of-binary-actuation-technology/.
- ↑ "World's first fully digital valves open up engine possibilities" (in en-US). 2018-08-11. https://newatlas.com/camcon-digital-iva-valve-system/55827/.
- ↑ "New Cambridge business targets accurate oxygen delivery and other medical markets | Business Weekly | Technology News | Business news | Cambridge and the East of England". https://www.businessweekly.co.uk/news/biomedtech/new-cambridge-business-targets-accurate-oxygen-delivery-and-other-medical-markets.
- ↑ "CBA Grace". https://copplestone.pages.cba.mit.edu/bistable_actuation/.
- ↑ Plante, Jean-Sébastien (2006). Dielectric elastomer actuators for binary robotics and mechatronics (Thesis thesis). Massachusetts Institute of Technology. hdl:1721.1/35305.
- ↑ 7.0 7.1 Chen, Qiao; Haddab, Yassine; Lutz, Philippe (2011-02-01). "Microfabricated bistable module for digital microrobotics" (in en). Journal of Micro-Nano Mechatronics 6 (1): 1–12. doi:10.1007/s12213-010-0025-2. ISSN 1865-3936. https://hal.archives-ouvertes.fr/hal-00558415/file/JMNM2010_Yassine.pdf.
- ↑ Jean-sebastien Plante and Steven Dubowsky (6 November 2007). "Binary Actuation". CiteSeerX 10.1.1.683.6625.
- ↑ 9.0 9.1 Vogan, J.; Wingert, A.; Plante, J.-S.; Dubowsky, S.; Hafez, M.; Kacher, D.; Jolesz, F. (2004). "Manipulation in MRI devices using electrostrictive polymer actuators: With an application to reconfigurable imaging coils". IEEE International Conference on Robotics and Automation, 2004. Proceedings. ICRA '04. 2004. IEEE. pp. 2498–2504 Vol.3. doi:10.1109/robot.2004.1307436. ISBN 0-7803-8232-3. http://dx.doi.org/10.1109/robot.2004.1307436.
- ↑ Wygnanski, Wladyslaw, "Sound pressure active transformer", GB patent 2150789, published 1987-02-25
- ↑ Wygnanski, Wladyslaw & Robin Whittaker, "Electromagnetic actuators", GB patent 2207812, published 1989-02-08, assigned to Out Board Electronics Ltd.
- ↑ Wygnanski, Wladyslaw, "Improved electro-magnetically operable device", GB patent 2369931, published 2004-06-30, assigned to Camcon Ltd.
- ↑ Wygnanski, Wladyslaw, "Improved actuator requiring low power for actuation for remotely located valve operation and valve actuator combination", GB patent 8006952, published 2007-06-27, assigned to Camcon Ltd.
- ↑ Wygnanski, Wladyslaw, "Rotary electromagnetic actuator", EP patent 2977567, published 2017-10-11, assigned to Camcon Auto Ltd.
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