This issue’s articles:
• 4D motion synchronized to your videos
• When to choose touchless vs. shaft-type sensors
• Feed forward control for better cylinder response

Featured video: Immersit 4D motion

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Synchronized Motion For Your Home Video/Game


Unveiled at the Consumer Electronics Show in Las Vegas this year, a company called Immersit has created a 4D a system that takes in-home entertainment to a new level.

Their product includes a control hub and four motion devices — with one electric motor-driven “base” placed under each leg of a couch or chair. Together they move the seated viewer forward, back, up, down and sideways.

How it works
The company’s software analyzes colors, frame frequency and audio frequencies to determine when and how much action / movement is required. The system synchronizes movement to the on-screen action. Target cost is that of a premium laptop. Their founder says they are working to have it in the market by end of this year.

Touchless vs. Shaft Technology for Angle Sensors
There are applications that are better suited to using a shafted rotary position sensor and others where a touchless (free-floating magnetic) one is a better choice. This tip presents several application situations and which type of sensor is preferred for that application as a guide to help with selection in general.

Applications that benefit from use of a shaft-type sensor

- Applications in which a dancer arm is being used to measure tension of a wire or foil or fabric in a production machine and there is no other shaft available.

- Applications where the sensor needs to be part of a gear box or geared actuator and has a gear on its shaft.

- When replacing a contacting potentiometer type or RVDT-type sensor that had a shaft of same size.

- When the measurement site is very far from where the sensor can be mounted due to design considerations such as extreme heat.

Applications that benefit from a touchless sensor

- Applications where an angle measurement is made through the enclosure or machine wall.

- Applications seeking an IP69K sealed sensor

- When no sensor wear is desired

- Applications that have ultra-high vibration of the rotating shaft

- When a small radial misalignment of the applications rotating shaft may occur

Touchless sensor benefits

- Completely enclosed magnet and sensor for superior sealing properties

- No wear because no contact

- Radial and axial misalignment do not necessarily have to be compensated with expensive couplings

- Vibration from drive shaft / magnet marker does not get transferred to sensor providing maximum robustness

- Flexible mounting of sensor on front or on back of a mounting plate

- Can measure through non-magnetic walls <1/4”.

Feed Forward: An Overview For Better System Response

In some motion control applications a very high degree of system responsiveness is required. For these applications feed-forward gains could be implemented outside of a control loop.

Some applications work great with feedback loop control, often a PID algorithm (Proportional Integral Derivative). However, those are reactive and take time to respond after an error or disturbance is generated. So augmenting that reactive system with feed forward compensation can often help applications that need to react more smoothly and precisely if the disturbance is measurable, predictable and can’t be handled by feedback control.

In the case of cylinder control, by utilizing measured position along with velocity and acceleration, a feedforward gain can be calculated to predictively compensate for errors and disturbances. The idea is to more closely match actual cylinder motion with ideal desired motion in spite of jolts, vibrations, oil compression, etc. There is a good article on this on Hydraulics & Pneumatics' website—link here.

If If you have a question about position sensors for your specific application, Novotechnik engineers would be glad to speak with you. Contact us at Email Novotechnik or call 800-667-7492.

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