FTC Hardware
Motor Power Table PDF Print E-mail
Written by The Cougars   
Thursday, 30 October 2014 13:44
 Traditional Spec Sheet Limit DataSpec Sheet Power Data
Motor NameUnloaded Rotational Velocity (RPM)Stall Torque (oz/in)Stall Torque (Newton/meters)Rotational Velocity at Max Output
(RPM at Max Output)
Rotational Velocity at Max Output (Radians/Second)Torque at Max Output (oz-in)Torque at Max Output (Newton/meters)Power (Watts)
Tetrix DC Motor V21503002.127483192.2517.4
AndyMark Neverest Motor1503502.478392581.8215.8
Tetrix DC Motor1503002.128991631.1510.7
Matrix HT Motor1962331.65115121220.8610.4
Matrix Motor1961601.1311612800.566.9
PF XL220560.4011012330.232.6
NXT Servo170700.49859380.272.4
PF M405150.112022180.061.2
PF E78050.043904120.010.6
Last Updated on Thursday, 30 October 2014 13:54
 
AndyMark NeveRest Motor Notes PDF Print E-mail
Written by The Cougars   
Sunday, 12 October 2014 19:26

Interfacing the new AndyMark NeveRest Motor with the HiTechnic Motor Controller

We have tested the new AndyMark NeveRest Motor and it works well with the TETRIX/HiTechnic Motor Controller. Here's what you should expect and what you need to do to make it work the way you want on an FTC robot. We will use motorD as our motor in our examples.

First we need to agree on some terminology. The TETRIX shaft encoder used with the TETRIX motors is a US Digital e4P with a 360 degree encoder wheel. Model E4P-360-236-N-D-H-D-B. To use US Digital's terminology it produces 360 Cycles Per Rotation (CPR) or 1440 Pulses Per Rotation (PPR). It is a quadrature encoder producing 4 Pulses per Cycle. In FTC use, with ROBOTC, it will produce 1440 PPR, ticks, or a count of 1440 in nMotorEncoder[motorD] per revolution.

The AndyMark NeveRest motor's built in encoder produces 280 cycles per revolution (CPR). We tested it. As expected with 280 CPR, it outputs 1120 PPR, ticks, or a count of 1120 in nMotorEncoder[motorD] per revolution. 

So, here's the only tricky bit. The NeveRest motor’s 1120 PPR is only approximately 78% of the TETRIX Motor’s 1440 PPR. You need to adjust your range when running under PIDControl from 0-100 down to 0-78.

The HiTechnic motor controller expects 1440 PPR and is "tuned" to drive a Tetrix motor at about 150 rpm when using PIDControl and a commanded speed of 100% motor[motorD]=100. That is, the motor controller will up the power as necessary to try to achieve 3600 Pulses per second when commanded to run the motor at 100% speed, or at about 1800 Pulses per second when commanded to run the motor at a speed of 50%.

At full speed, 150 rpm, the NeveRest motor encoder will only produce 2800 Pulses per second. Using the 1440 PPR Tetrix motor with shaft encoder will produce 2800 ticks at 78% speed or 117 rpm. Since the motor controller will try to adjust power as necessary using the built in PID to achieve the correct speed, a speed setting of 78%, i.e. motor[motorD]=78; will achieve full speed on the NeveRest Motor. Likewise, a speed setting of 39, motor[motorD]=39; (½ of 78) will achieve approximately 50% speed on the NeveRest motor running under PIDControl. Any speed from 78% to 100% will cause the controller to run the motor at 100% speed. Please keep in mind that this only works this way under PIDControl and not under openLoop. Under openLoop mode you are just passing a percentage power to the motor controller and you will need to revert to using 0 through 100 for your power levels if you want to get full range & power out of the NeveRest motor.

Additional usage information

Bill Gardner over at Cheer4FTC is also testing the NeveRest Motor and pointed out that it "natively" spins the opposite direction of a TETRIX DC Motor. So be aware any time you replace a TETRIX motor with a NeveRest 40 or vice-versa you will want to reverse the direction of spin programmatically. If you are not using the built-in encoder you could also just reverse the red and black power wires...

Last Updated on Monday, 13 October 2014 15:32
 
HiTechnic Servo Controller email PDF Print E-mail
Written by Jamie Diamond   
Wednesday, 01 October 2014 22:07
Hi Jamie,
I just talked to our engineer and got some details.
The servo voltage is 6V. The current limit is 5A shared between all 6 servos that are attached. In other words, the 800mA limit that you are getting from FIRST is based on all 6 servos being stalled at the same time. If only one servo is stalled and active, than all 5A can go to that one servo.

I also verified that the 5A limit is protected in the controller and it will shut down if exceeded.

Best Regards,
HiTechnic Support
 
Reference Resources PDF Print E-mail
Written by The Cougars   
Sunday, 28 September 2014 05:25

HiTechnic & Matrix Controllers

FTC Motors

Build A Better Bot Workshops

Shop References
(courtesy of Bernez's Knifemaking Info Pages)

 

Attachments:
Download this file (AndyMark am-2964 NeveRest40.PDF)AndyMark am-2964 NeveRest40.PDF[ ]93 Kb01/10/14 08:02
Download this file (FTC Workshop - content - final.pptx)Build A Better Bot workshop[ ]9895 Kb25/10/14 18:43
Download this file (HiTechnic-Motor-Controller-Specification-v1.4.pdf)HiTechnic Motor Controller brief v1.4[ ]155 Kb10/10/14 13:16
Download this file (hitechnic_motor_controller_-_brief_v1.3.pdf)HiTechnic Motor Controller brief v1.3[ ]194 Kb10/10/14 13:16
Download this file (hitechnic_servo_controller_-_brief_v1.2.pdf)HiTechnic Servo Controller brief[ ]168 Kb01/10/14 07:18
Download this file (MATRIX-Controller-Specification-v1.2.pdf)MATRIX Motor Controller Specification[ ]165 Kb09/10/14 09:18
Download this file (MATRIX_HTMotor_Spec_v2.pdf)MATRIX HT-Motor[ ]250 Kb02/10/14 08:53
Download this file (MATRIX_Motor_Spec_v2.pdf)MATRIX Motor[ ]245 Kb02/10/14 08:52
Download this file (tap_and_drill_chart_-_english.pdf)Tap & Drill Chart - English sizes[ ]115 Kb01/10/14 08:14
Download this file (Tetrix_DC_Motor_V1.pdf)Tetrix DC Motor[ ]122 Kb01/10/14 08:01
Download this file (Tetrix_DC_Motor_V2.pdf)Tetrix DC Motor V2[ ]1983 Kb01/10/14 08:02
Last Updated on Thursday, 30 October 2014 13:53
 
Recommended Tools and Parts PDF Print E-mail
Written by Evan Hollins   
Monday, 05 August 2013 20:09

Here is a list of the extra parts and tools we use that don't come in the kit.  

 

Powerpole connectors.  We use the pairs. You'll need the 30 amps for battery connections and the 15 amp for the Samantha connections and maybe some of the motor controllers.  The only difference between the two sizes is the size of the hole for the wire in the crimp connectors.

Nylon Insert Hex Locknuts.  We order these from McMaster-Carr.  We also order 6-32 machine screws in a wider variety of lengths than comes with your kit.  We use the standard socket-head where we can (they are easiest to use) but then we have a wide variety of both button-head and even flat-head for countersinking into the side of gears when we are doing cascaded gear systems. 
 
Tools:
We color code all of our tools using a ROY G BIV scheme.  We started out with Red being 1/8" and worked down from there.  It turned out that 1/8" isn't used so we ended up coding all of our hex keys in Orange(7/64), Yellow(3/32), Green(5/64), & Blue(1/16).  I would encourage you to do the same.  It makes grabbing the right tool much quicker.

Another rather simple "innovation" our team makes use of is velcro to attach our electronics.  Again from McMaster-Carr we purchased a bunch of sticky-back hook & loop fastener - http://www.mcmaster.com/#9273K34  and some double sided hook & loop fastener http://www.mcmaster.com/#94905K62.  We'll lay down loop side on a panel on the robot and hook side on the bottom of all our electronics, that lets us rearrange electronics easily.  However, a problem we have had is with ESD (Electro-Static Discharge).  It may be related to having our electronics effectively insulated from our chassis so be careful with this one.

These thermal-fuse protected motor power cables will also save you some money in the long run.  http://parts.ftcrobots.com/store/detail.aspx?CategoryID=161&by=9&ID=6402&c=1&t=&l=  Again though, be forewarned.  They both limit the power you can get out of a motor and they do go bad over time as you trip them over and over.  But at less than half the price of a motor they will save you money.  The last two years we had them on our drive train but not on our arm or scissor-lift.  In both of those cases we needed absolutely every ounce inch of torque or motors were producing so we had to forego them.  In the case of the arm we wrote a programmatic solution to protect the motor on the arm from stalling and burning up motors.  We may go to a similar solution on the drive train this year in order to get more power out of our motors without burning them out in the case of a stall.  Dave Fort quote "Torque must be greater than traction".  We now test to make sure that if our robot tries to push an immovable object the wheels spin rather than having the motors stall.
 


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