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Motors and Servos - Answer Thread

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  • Buckaroo Banzai
    replied
    Switches to disable servos

    Originally posted by FTC8668
    Our servos are moving when the robot is powered up. This behavior appears to be caused by the servo controllers momentarily writing a voltage to the servo port at power up. Unplugging the servo controller then, obviously, doesn't fix this behavior. The only fix that has been suggested is to put a switch between the servo controller and the servo itself. Is this legal if the switch is put on an extension cable such that neither the servo nor the servo controller are modified?


    Answer: No. This usage of switches would fall under <RE17> Additional Electronics and is not allowed (i.e. it is not a sensor and not connected to the Core Device Interface Module)

    Leave a comment:


  • Ming the Merciless
    replied
    RE09 - Spare Motors

    Originally posted by FTC11703
    Hi,

    This is a strange question. When our team was at a qualifying tournament, the lead inspector told us that since we had 8 motors on our robot, that if by chance we had an extra motor on our robot cart, not on the robot, when we left the queuing area to compete, we would be disqualified. He went so far as to say, if we even left a spare motor in the queuing area on the way to compete, we would be disqualified. It this true? And if it is, does this extend to servos and batteries as well? We always carry a spare battery on our cart just in case.

    Thanks in advance,
    Team 11703
    A: Rule <RE09> refers only to the motors that are part of a legal Robot. Teams are allowed to bring as many spare motors, servos, batteries, etc. as they wish on the Robot cart.

    Leave a comment:


  • Buckaroo Banzai
    replied
    Non-Powered Motors

    Originally posted by FTC8391
    Would unpowered DC motors used for purely aesthetic/decorative purposes count towards the <RE09> 8 motor limit?

    Thanks,

    FTC Team 8391, W-Prime


    Answer: Yes. All motors on the robot count towards the 8-motor limit, regardless of their current usage status.

    Leave a comment:


  • Ming the Merciless
    replied
    RE10 - Linear Servos

    Originally posted by FTC11825
    Hello, I was looking to get a new autonomous button pusher for our team. Would this Linear Actuator we were looking at buying be within the Robot Inspection Rules if we were to get 2.

    Here is the link...
    http://www.robotshop.com/en/firgelli...ml#description

    Thanks,
    Graveyard Shift
    #11825 MHS Robotics
    A: Option R, using the 3 wire RC servo connector and limited to 5 V is legal. The other versions are not allowed.

    Leave a comment:


  • Buckaroo Banzai
    replied
    Linear Actuator

    Originally posted by FTC10527
    As an off the shelf part, is the linear servo https://www.servocity.com/hda10-2 Allowed in robot builds?


    Answer: As sold, the above servo does not meet the requirements of being able to be powered and controlled by any of the alllowed Servo Controllers and is therefore not allowed.

    Leave a comment:


  • Buckaroo Banzai
    replied
    Servo Boosters

    Originally posted by FTC6299
    We have been having a lot of problems with getting servos to work properly when the cables reach a certain length, so this serves to be a big problem when there are servos on the end of a lift mechanism. We found that the signal from the modern robotics servo controller was not strong enough to properly control the servos at extended lengths (starting around 3-4 feet of extension), but boosted extensions sold by servo city fix this problem. However, we were not sure whether or not these extensions were legal. Are servo signal boosters legal?


    Answer: No. Servo Boosters would fall under the category of "Additional Electronics" and are not allowed per <RE17>

    Leave a comment:


  • Buckaroo Banzai
    replied
    Additional Servos on Servo Controller w/ VEX EDR Motors

    Originally posted by FTC11260
    The rules state "Core Servo Controllers and Legacy TETRIX Servo Controllers may control up to two (2) VEX EDR 393 Motors
    per module. A VEX Motor Controller 29 must be used in between a servo module and each VEX EDR 393
    motor."
    We would like to control 2 additional servos and are wondering if we need to use another controller to do so. I understand the 5 amp stall requirements, so I suspect the answer is no. Our servos and motors will be used one at a time, so having multiple stalled devices is unlikely. Thanks for you reply.


    Answer: No. Two EDR Motors fully consumes the power budget for the Servo Controller.

    Leave a comment:


  • Ming the Merciless
    replied
    RE10 - Linear Servos

    Originally posted by FTC3491
    We were hoping to confirm that the Actuonix (formerly Firgelli) L12-R and L16-R series linear servos are still legal for use.
    A: Linear servos are legal provided they are the 6 Volt version and have the three wire connector that plugs into the Servo Controller.

    Leave a comment:


  • Ming the Merciless
    replied
    RE09 - Gearbox Removal

    Originally posted by FTC8699
    May we remove the gearbox on Tetrix or Neverest motors and just use the motor?
    A: Yes, the motors may be used without the gearboxes.

    Leave a comment:


  • Buckaroo Banzai
    replied
    12v Linear Servo

    Originally posted by FTC6433
    Please clarify the legality of this Servo: https://www.servocity.com/hdls-12-2-12v

    Assuming it is controllable from the MR Servo Controller Module and meets the specified power requirements, is it legal because of Rule RE 10 as it labeled as a servo, or is it illegal because it violates the COTS 1 DOF rule RM 02?


    Answer: This servo is not allowed. This servo is not compatible with the allowed servo controllers. It requires a 12v power connection in addition to the standard servo control signals.

    Leave a comment:


  • Marvin the Paranoid Android
    replied
    Motors and Servos - Answer Thread

    Originally posted by FTC7190
    My team and I were wondering whether it is legal per rule RG01J to remove air from a funnel using a vacuum pump. We are not compressing or storing air and there are no pistons or valves involved in the design. The vacuum pump is from Amazon: https://www.amazon.com/Karlsson-Robo.../dp/B00DYA21PU. We are not using the motor that comes with the pump. We are converting it to an AndyMark NeverRest motor. Inside the pump is a piece that spins. This pieces turns at an offset and makes the rubber part on the outside pump out the air from the funnel. There is only one degree of freedom in this design. Thanks so much!
    A: We found out that it is a diaphragm pump. Our ruling is that as long as the outport port of the pump is not blocked or sent through a hose, the pump should not build up any pressure. If those constraints are followed, then this would be considered a legal part.

    Leave a comment:


  • Buckaroo Banzai
    replied
    Linear Servos

    Originally posted by FTC11255
    Are linear servos allowed? There is no notion that they are, or are not. It is just the rotational ones that are allowed. Assuming the connection to the servo controller is the same, can a linear servo be used?


    Answer: <RE10> does not constrain the nature of the output of a servo. For a servo to be legal, it must:
    • be marketed/sold as a servo
    • be electrically compatible with allowed Servo Controllers (6v and within the current limit for the controller)
    • be controlled/powered by an allowed Servo Controller


    Team using "unusual" servos should be prepared to support the legality of their servos by bringing documentation for the servo (specifications, etc)

    Leave a comment:


  • Buckaroo Banzai
    replied
    Linear Actuators

    Originally posted by FTC5401
    Are we able to use these actuators on the robot?

    Zowaysoon 12V Electric Linear Actuator 100m/4inch Stroke 1500N DC Motor Linear Motion Controller with Limit Switch

    Stroke length:100mm(4inch)
    • Voltage: 12VDC** Noise Value: >65dB
    • Load/Thrust/Force Capacity:1500N =150kg(330Ib)
    • Speed:5.7mm/s
    • Duty Cycle: 25%** Protection class:IP54


    Answer: No. The above linear actuator is not an allowed DC motor nor an allowed servo and falls under the <RE17> Additional Electronics rule

    Leave a comment:


  • Ming the Merciless
    replied
    RG02 b - Initialization Routine Warning Label

    Originally posted by FTC8424
    Hi there! We just went through an inspection before our league meet and the inspector told us that we needed to have the servo movement stickers next to EACH servo that was on our robot, not just a single one to alert folks that the servos might move. In the past we only needed one and it's not exactly convenient for us to have a place to put those near every servo. Do we really need multiple stickers, or will one do for the entire robot?
    A: Rule <RG03b> requires just one warning label located near the Main Power switch.

    Leave a comment:


  • Ming the Merciless
    replied
    RE16 - Continuous Rotation Modification

    Originally posted by FTC8688
    Are we able to modify a 90 or 180 degree servo to make it continuous rotation servo? Specifically the Hi-Tec Servo Model HS-485HB which list Specifications as 360 degree Modifiable. http://www.andymark.com/product-p/am-2543.htm
    A: Because the modification involves changing or modifying the gears and does not involve the electronics or wiring this modification is allowed.

    Leave a comment:

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