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Post by clyevo on May 2, 2015 15:43:04 GMT
from what i understand, the motor itself are able to withdraw extra current to generate torque more than the specification but i suspect this will cause it to move slower and how long it can hold this state before it wear out and die depends on service factor of the motor in this quite detailed article link below: ecmweb.com/motors/understanding-induction-motor-nameplate-informationyou can scroll to Fig. 1 shows the general shape of torque-speed curves for motors with NEMA Design A, B, C, and D characteristics. and you can see that NEMA D motors can hold 280% of rated torque at 0 speed before stalling (probably thats what the graph means anyway)
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Post by vicpopo on May 2, 2015 16:18:38 GMT
Thanos often said that sometimes just 2 motors have to move the sim and I'm quiet agree with.But they don't have the whole weight. Look at ckas 6 dof datasheet, it's a good base for finding the right motors according the wanted payload. For the régulation I just advice to find inverter which have a vector flow control, not only U/f regulation.
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Post by blizzard on May 2, 2015 19:20:13 GMT
from what i understand, the motor itself are able to withdraw extra current to generate torque more than the specification but i suspect this will cause it to move slower and how long it can hold this state before it wear out and die depends on service factor of the motor in this quite detailed article link below: ecmweb.com/motors/understanding-induction-motor-nameplate-informationyou can scroll to Fig. 1 shows the general shape of torque-speed curves for motors with NEMA Design A, B, C, and D characteristics. and you can see that NEMA D motors can hold 280% of rated torque at 0 speed before stalling (probably thats what the graph means anyway) Ok clyevo, I'll contact my motor provider and request for such a datasheet and discuss that border situation.
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Post by blizzard on May 2, 2015 19:33:26 GMT
Thanos often said that sometimes just 2 motors have to move the sim and I'm quiet agree with.But they don't have the whole weight. Look at ckas 6 dof datasheet, it's a good base for finding the right motors according the wanted payload. For the régulation I just advice to find inverter which have a vector flow control, not only U/f regulation. Hi vicpopo, the video of ckas 6 DOF are interesting, because I watched the movement of the 6 lever especially exactly. Yes, normally, there are regulary more motors in action. The datasheet unfortunately refers to very small angle. Thanos, would you confirm because of your experiences, that regulary at least 2 motors are in action and they are managing the payload nearly alone under condition of extrem flexion position(e.g.45°) or there an extremely situation are possible and imaginable where one motor is carrying the payload only? regards and thanks Rolf
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Post by vicpopo on May 2, 2015 20:03:06 GMT
When you say that 6dof ckas has small angles that suprises me ! i will check once again ! A situation where just one motor works, I don't imagine on what position. For me they always works on pair , one push the other pull ! When you are for example on max position on roll situation .With my motors placement it's the most critical situation on my sim.,n these case 2 motors work together, not only one. Look at my video link below , after 3min I filmed all the motors in motion ! youtu.be/RbDuAr90YQQ
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Post by vicpopo on May 2, 2015 20:25:36 GMT
When i looks at your wanted specifications for your sim it mattches to the one ckas with the following specs : Payload 1000kg Power consumption 25 A 230vac Max pitch angle + - 24degrees
Ok not 45 degrees.Tha question is : is it really necessary 45 degrees? Lol In my opinion it's depends also from the mecanical heim joint max angle.With special heim joint which allow bigger angle it's maybe possible. For the motors if they can handle such specs ,I think that it could BE ok!
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Post by blizzard on May 2, 2015 21:18:52 GMT
The video is very good and I'm most impressed of your setup! It's nice to study the movements of the 6 motors synchronized in different phases. Yes, you are right, 45° pich or roll of the platform is really an extremely position, but I'm looking for the limits of possibility. Surely the impression in the brain depends of a lot of other physiological and physical factors. A fighter pilot for e.g. believes(under IFR condition), that he flies straight but in reality he is decending etc. In so far maybe it's not necessary indeed to have such extremely angle. In the attachment you can see my moving platform mockup in a low horizontal position. The second picture shows the right motor in front with it's lever in a max. position above solely and the other motors-lever are in basic position below furthermore, but I think more and more, that's a theoretical possibility only and it will probably not happen by a authentical and software controlled machines. regards Rolf
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Post by clyevo on May 3, 2015 3:14:13 GMT
In that picture i can see what u meant is 22.5 degrees roll either way (left or right) equates to 45 degrees total if combine both way. I also trying to get the highest angle possible for my setup. The highest angle heim joint i can find are max 17 degree, if add high misalignment reducer can go 30 degree (60 degree total). More than that: its possible to custom CNC high misalignment reducer like DoctorD in Xsim forum. He made the heim joint go 40 degree (80 degree total). I saw his video of the motion simulator doing roll at 40 degrees, its crazy steep, i think u might get thrown of the seat, haha. Too bad his thread is dead, i was hoping to see the video of him riding the completed motion simulator. the image just to illustrate the post, i modified from 3d sketching of Yue Qi model, i hope he dont mind
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Post by vicpopo on May 3, 2015 6:12:38 GMT
Look at Billo's setup on user project section .You will find a solution to increase heim joint angle greater as 17 degrees. You have to let machine pieces but you will get bigger angle
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Post by blizzard on May 3, 2015 6:51:57 GMT
Hi clyevo and vicpopo, the flexion angle of the platform is not the problem for me, because I solved it by using a combination of swivel heads and fork joints as well as ball-bearing(see the pictures below). Therewith I was able to get a flexion angle of about until 45°. The crucial question for me is furthermore, whether an extremly situation is possible where only one motoraxis-lever are isolated in a extremly position with the high load of one motor or is it always an interaction of different motors, at least two? Because this question is important for me, whether if I had chosen the right gearmotor. Maybe I'll get a calculation of the different weight loads of the motorgear-levers e.g. in a position of 45° by a mathematican taking into account of 6 DOF. regards Rolf
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Post by Mitch on May 3, 2015 16:09:28 GMT
Hi clyevo and vicpopo, the flexion angle of the platform is not the problem for me, because I solved it by using a combination of swivel heads and fork joints as well as ball-bearing(see the pictures below). Therewith I was able to get a flexion angle of about until 45°. The crucial question for me is furthermore, whether an extremly situation is possible where only one motoraxis-lever are isolated in a extremly position with the high load of one motor or is it always an interaction of different motors, at least two? Because this question is important for me, whether if I had chosen the right gearmotor. Maybe I'll get a calculation of the different weight loads of the motorgear-levers e.g. in a position of 45° by a mathematican taking into account of 6 DOF. regards Rolf Good solution, actually your fork joint design reminds me of what CAE uses on their full motion sims: www.cae.com/uploadedImages/Content/BusinessUnit/Defence_and_Security/Media_Centre/Photos/CAE-built-KC-30A-full-flight-mission-simulator.jpg
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Post by clyevo on May 3, 2015 16:51:36 GMT
Hi clyevo and vicpopo, the flexion angle of the platform is not the problem for me, because I solved it by using a combination of swivel heads and fork joints as well as ball-bearing(see the pictures below). Therewith I was able to get a flexion angle of about until 45°. The crucial question for me is furthermore, whether an extremly situation is possible where only one motoraxis-lever are isolated in a extremly position with the high load of one motor or is it always an interaction of different motors, at least two? Because this question is important for me, whether if I had chosen the right gearmotor. Maybe I'll get a calculation of the different weight loads of the motorgear-levers e.g. in a position of 45° by a mathematican taking into account of 6 DOF. regards Rolf what is that joint for originally. May i know where do u get it? If online can give me link. It looks more stable than conventional heim joint and bigger angle. Can you post video on the movement of the joint?
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Post by blizzard on May 3, 2015 17:59:10 GMT
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Post by clyevo on May 4, 2015 9:26:44 GMT
the arm lever would be 25cm and i am planning to use plain steel for the platform, roughly the total payload including my weight probably 170kg i am yet to choose the motor and gearbox but currently i am looking at this options:
1) motor power :1.5KW 4P 220/380V ratio:80 output speed:17.5r/min output torque:548N.m service factor :0.9
tolerable weight bearing per motor : 548Nm/0.25m = 2192N = 223 kg(force)
2) motor power :2.2KW 4P 220/380V ratio:60 output speed:23.3r/min output torque:648N.m service factor :1
tolerable weight bearing per motor : 648Nm/0.25m = 2592N = 264 kg(force)
3) motor power :1.5KW 4P 220/380V ratio:60 output speed:23.3r/min output torque:417N.m service factor :0.8
tolerable weight bearing per motor : 417Nm/0.25m = 1668N = 170 kg(force)
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Just wondering, if i reduce motor speed settings through thanos board, will it increase or reduce the torque or no difference in torque output?
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Post by vicpopo on May 4, 2015 14:58:05 GMT
For me it will a little bit increase the torque ! But remember there are anorher paramaters which are also important to setup your sim : - the regulation mode , choose an inverter (if you can) which can make the vector flow control (in place of U/f regulation -the PID setup ( very important) -the ramp up and down acceleration - choose first the minimum value ( zero if you can ) without inverter errors !
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