Torque Motor Selection
Torque Motor Selection
(OP)
I am looking to get a DC motor that I am going to be using to provide force feedback to a flight simulator flight stick. The motor is going to have a very limited range of motion, and be used only to create forces without rotating. I need a motor that is able to generate controllable forces between 0 and 140 lbs to get the desired stick forces. I have been looking for torque motors, but have been unable to find any that will work. My question is if I am using the right approach by selecting torque motors, and if so, does anyone have any ideas where I could find something that will work? I am pretty new to motor control stuff, and was wondering if I need a torque motor at all. Would a different type of motor do the trick better? I was unsure if it would be bad on the motor to not allow it to spin, and force it in the opposite direction it is trying to spin, as will happen w/ my system. Any suggestions will be greatly appreciated.
Thanks.
Thanks.





RE: Torque Motor Selection
Try a fan cooled DC motor and vary the rotor voltage. The torque will vary.
respectfully
RE: Torque Motor Selection
Thanks
RE: Torque Motor Selection
You can stall a DC motor and you can force it backwards. Cooling and brushes are the issues. You may have to use forced cooling from an external fan. You may have to experiment with different grades of brushes for best performance at a standstill.
You can use a spring. A motor driven screw-jack can compress the spring and vary the force.
I haven't seen electric power steering, but i haven't seen everything.
I am familiar with back-up steering systems used on front-end loaders and log skidders and forwarders. These units have hydraulic steering. No hydraulic pressure, no steering. The steering pressure pump is a fairly large hydraulic pump driven off the engine. It is actually large enough to stall the engine at slow speeds and part throttle.
Some jurisdictions mandate an electric backup pump to maintain some steering ability in the event of engine failure. This feature may be found in mountainous regions.
This is not what you are looking for.
How about hydraulic positioners. You can use the positioner to compress a spring and so convert linear movement into torque or force.
RE: Torque Motor Selection
RE: Torque Motor Selection
or similar products.
RE: Torque Motor Selection
LPS for you.
respectfully
RE: Torque Motor Selection
Thanks.
Richard
RE: Torque Motor Selection
The first issue is usually dealt with thru an auxiliary blower or, in small sizes, by oversizing the motor frame. The second issue is usually dealt with by using a larger motor and not exciting the armature fully thus keeping the commutator currents well below design levels.
Good luck!
RE: Torque Motor Selection
http://www.polysci.com/Motors/torquembrshless.html
RE: Torque Motor Selection
http://www.bodine-electric.com/etorq/
RE: Torque Motor Selection
For a motor to simulate a resistance torque (not a force) it has to be at least 10 times faster response time than the force rate or change on the stick. There is always a time delay for the current to build inside the motor coil and produce the resistance torque. Therefore, the motor coil resistance and inductance should be as small as possible and the voltage as high as possible. This will result in a current limiter circuit, and a very high voltage drive a sophisticated feedback control system. Only mechanical spring will respond instantly without any delay.
From the height of my 30 years of experience it amazes me that from time to time engineers come with this inventive idea to simulate resistance using a motor without paying attention to the instant response time needed and its implications on the size of the motor the voltage and current needed to try to achieve what a simple spring will do.
RE: Torque Motor Selection
RE: Torque Motor Selection
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