Hydraulic Actuator Limits
Hydraulic Actuator Limits
(OP)
Hi All,
Thank you for taking the time to read this post.
I am inquiring to see if these sort of speeds are achievable with a hydraulic actuator.
80 mm travel. Time : 8ms AVG Speed: 10m/s . Opening force: 1100N
70 mm travel. AVG Speed: 8.75 m/s Time: 8m/s. Opening force: 1100N
60 mm travel. etc...
50mm travel. etc...
Basically a device that can vary distances between 2-80mm, but open in 8 milliseconds, and seperate a 1100N force.
I'm guessing with this sort of speed/acceleration requirements some sort of braking device will be required too(?). I was reading on a different thread something about "hydraulic piston cushion"
Before I begin researching this topic further, I just thought it might be worthwhile to know if these accelerations and speeds are achievable with a hydraulic actuator? Also if it is, how big do you think the pump and the reservoirs will have to be?
Thank you for your time.
Thank you for taking the time to read this post.
I am inquiring to see if these sort of speeds are achievable with a hydraulic actuator.
80 mm travel. Time : 8ms AVG Speed: 10m/s . Opening force: 1100N
70 mm travel. AVG Speed: 8.75 m/s Time: 8m/s. Opening force: 1100N
60 mm travel. etc...
50mm travel. etc...
Basically a device that can vary distances between 2-80mm, but open in 8 milliseconds, and seperate a 1100N force.
I'm guessing with this sort of speed/acceleration requirements some sort of braking device will be required too(?). I was reading on a different thread something about "hydraulic piston cushion"
Before I begin researching this topic further, I just thought it might be worthwhile to know if these accelerations and speeds are achievable with a hydraulic actuator? Also if it is, how big do you think the pump and the reservoirs will have to be?
Thank you for your time.





RE: Hydraulic Actuator Limits
HPost CEng MIMechE
RE: Hydraulic Actuator Limits
Just like usual the hydraulic guys start put with the components without looking into what they must do.
A rough calculation assuming that 1/3 of the time ramping up, 1/3 of the time at constant velocity and the last 1/3 ramping down results in a peak speed of 15 m/s and acceleration rates of about 852g. The 852g is a killer. If khonfahm expects to do this with only 1100N of force then it will be tough to accelerate the piston and rod let alone any load.
852g!!!! I could lower this by a little by assuming 1/2 of the time is accelerating and the other half is decelerating but it wouldn't make any difference really and the peak speed would increase to 20 m/s
Peter Nachtwey
Delta Computer Systems
http://www.deltamotion.com
RE: Hydraulic Actuator Limits
I need to be able to open and close the switch in 1/2 a 60hz cycle (8.333m/s). If the contact seperation distance is 80 mm.. this means 10 m/s average speed.
HPost - When you say they can get quite expensive - what sort of pricing are you talking about (this would be good to know as a ball park figure)? $10k+, $100k+ $200k+ USD?
RE: Hydraulic Actuator Limits
http://www.moog.com/products/motors-servomotors/li...
Khonfahm, what you haven't told us is how much mass you really need to move. This would tell us if some sort of gearing and be used.
Peter Nachtwey
Delta Computer Systems
http://www.deltamotion.com
RE: Hydraulic Actuator Limits
It would be impossible to achieve the acc and dec with a fluid system if the entire actuator length is contained within the stated stroke.
The cost would be towards the lower end because of the small size.
HPost CEng MIMechE
RE: Hydraulic Actuator Limits
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Hydraulic Actuator Limits
What is an acceptable acceleration and deceleration time and distance? Is it acceptable to have a higher force available during acceleration? Is positioning accuracy required? How frequently will it be actuating? Does it have to accurate both directions at that velocity? What temperature will it be operating in? Are there any other parameters that effect design like fire resistance, safety codes, size, and available power to drive the system?
I have designed a pneumatic system that will reach this type of speed and have proposed a hydraulic version and looked at electric versions. This application is an acoustic signal generator, what is your application?
Cost could range from $2000.00 to $50,000.00 depending on your application or it may not be physically possible.
Ed Danzer
www.danzcoinc.com
www.dehyds.com
RE: Hydraulic Actuator Limits
Khonfham should have provided the mass to move as well as any external force that needs to be overcome. Providing the force is useless. The NET force is determined by the peak acceleration * mass + frictional+gravitational forces.
When I get a question like this my first thoughts are watch out, this guy needs help and probably more than he is willing to pay for.
@Ed, you must have customers that are willing to shell out the big bucks. I can see reaching these speeds with pneumatics on a single shot basis. There are some videos of shooting ping pong balls at super sonic speeds on YouTube. I can see this being repeated often.
Peter Nachtwey
Delta Computer Systems
http://www.deltamotion.com