Difference between revisions of "Msc2G7:Expert3"

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(Created page with " == '''drive''' == The most influential decision for the design of the joint is the way the joint is driven. In this document we argue the different drive and the best suita...")
 
 
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__NOTOC__ __NOTITLE__
  
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== '''drive''' ==
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==Motors & Sensors==
  
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<div style="height:30px; width: 850px; margin:0px; padding: 0px; padding-top: 20px; border: 0px;">
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<div style="float:left; width: 90px; height 30px; border: 1px solid #aaa; margin-right:8px; " align="center">
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[[Msc2G7:Frontpage|''' BOP ''']]
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</div>
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<div style="float:left; width: 120px; height 30px; border: 1px solid #aaa; margin-right:8px" align="center">
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[[Msc2G7:Expert5|''' Weekly Planning ''']]
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</div>
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<div style="float:left; width: 130px; height 30px; border: 1px solid #aaa; margin-right:8px; " align="center">
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[[Msc2G7:Expert1|''' Joints&Calculations ''']]
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</div>
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<div style="float:left; width: 120px; height 30px; border: 1px solid #aaa; margin-right:8px;" align="center">
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[[Msc2G7:Expert3|''' Motors&Sensors ''']]
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</div>
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<div style="float:left; width: 90px; height 30px; border: 1px solid #aaa; margin-right:8px" align="center">
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[[Msc2G7:Expert4|''' Control ''']]
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</div>
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<div style="float:left; width: 130px; height 30px; border: 1px solid #aaa; margin-right:8px" align="center">
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[[Msc2G7:Expert6|''' Plenary Session 2 ''']]
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</div>
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<div style="float:left; width: 90px; height 30px; border: 1px solid #aaa;" align="center">
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[[Msc2G7:Questions|''' Questions ''']]
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</div>
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</div><br>
  
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The most influential decision for the design of the joint is the way the joint is driven. In this document we argue the different drive and the best suitable on for our design needs.
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==Servo testing==
 +
Servo testing 250gr on 30cm arm. Testing the power demand. <br/>
 +
http://re.hyperbody.nl/pdf/Film1.2.mp4 <br/>
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Servo testing 250gr on 40cm arm. <br/>
 +
http://re.hyperbody.nl/pdf/Film2_2.mp4
  
 +
== 6/5 computer, sensor and connection choices ==
  
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== '''Criteria for the drive''' ==
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'''1. One joint with sensor working ''' <br/>
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Raspberry pi/Arduino control motor with sensor
  
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1. Handle high torques/forces (or high speed with a gearbox)
 
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2. Power/weight ratio
 
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3. Accurately controllable
 
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4. Size
 
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5. Sharing energy
 
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6. Maintaining position
 
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7. (Degrees of freedom (+/- 180°) (actually possible for every drive))
 
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8. Accessible for testing
 
  
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'''2. Two (Micro)Computers Communicating '''
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ethernet/bluetooth
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'''3. Advanced control'''
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Consensus Algorithm
  
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== '''Drives''' ==
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==25/3 Adapt servos ==
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[[File:IMG_2917.JPG|300px]]
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<br/>
 +
<br/>
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The brown wired element on the right is the potentio meter. That measures the angle of the output axle of the motor. The turning angle of the meter is limited to less than 360 degrees. So that causes a problem when putting any gears on that axle to increase torque. The meter has to be replaced to the good axle of the right measurements.
  
 +
== 11/3 Type of Motor Decisions ==
  
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'''• Mechanical'''
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Based on some requirements for the motor, the decision was made to use a Servo Motor, instead of a Stepper Motor or a DC Motor.
  
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1. Powerful or high speed
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The requirements were the following:
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2. ± 500 W/kg (helicopter engines)
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o Fuel weight
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3. Not accurate
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4. Torque depended
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5. Hard: Fuel line through the tubes
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6. Hard: changeable gearbox?
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7. Accessible (helicopter engines) but expensive
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Extra’s:
+
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• Low efficiency
+
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• Safety hazard: explosion possibility
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• Weight mainly in joint
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• Emissions, not sustainable
+
  
 +
#  The position controllability of the axle of the motor
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#  A high power/weight ratio
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#  High accurately placed at a desired angle of the axle
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#  Being able to stall for some time
 +
#  Being low cost
 +
#  Availability of using a battery to power the motor
  
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'''• Hydraulic (to big)'''
 
  
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1. Unlimited high forces/speeds
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In the next 2 documents the decision of the Servo Motor is being explained further
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2. ± 800 W/kg (SAI, but very heavy)
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o Fluids weight
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3. Good controllable
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o Not accurate, speed varies
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4. Big (efficient when big)
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5. Hard: Fluid line through the tubes
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6. Hard (almost not possible)
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7. Specially made (expensive)
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Extra’s:
+
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• High efficiency
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• Safety hazard: high pressure fluids
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 +
[https://www.dropbox.com/s/vqyap2iolt25r9n/Pve%20motoren%20uitgebreid.docx?dl=0]
  
 +
[https://www.dropbox.com/s/yaukn9b1psq8r9r/PvE%20motoren.xlsx?dl=0]
  
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'''• Pneumatic (low forces, hard to share engery )'''
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== 5/3 Arduino testing ==
  
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1. low forces, high speeds (special gearbox needed)
 
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2. ± 450 W/kg (bosch)
 
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3. Good controllable, but not constant speeds
 
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4. Low weight, small
 
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5. Light tube of air through tube, but length motor and cyclinder can’t be to large!
 
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6. ? I think: easy but pressure drop?
 
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7. Specially made (expensive, not accessible)
 
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Extra’s:
 
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• High efficiency
 
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• No safety problems
 
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• Noisy
 
  
 +
[[File:FullSizeRender.jpg|400px]]
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Attempt to connect and control dynamixel 12a+
  
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'''• Electrical'''
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[[File:IMG 2840.JPG|400px]]
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Dynamixel control module/chip sn74ls241
  
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1. High forces/speeds
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== 4/3 Drive ==
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2. ± 3780 W/kg (himax, lightest (0.45kg))
+
The most influential decision for the design of the joint is the way the joint is driven. In this document we argue the different drive and the best suitable on for our design needs.
−
3. Good controllable and accurate
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4. Small and depends on needed torque
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5. Easy: wire through tube
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'''Criteria for the drive'''
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6. Easy (but overheating)
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7. Broadly accessible (cheaper)
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# Handle high torques/forces (or high speed with a gearbox)
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Extra’s:
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# Power/weight ratio
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• All weight in the joint (scaling problems)
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# Accurately controllable  
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• No Safety when electricity loss
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# Size
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• Efficient
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# Sharing energy
 +
# Maintaining position
 +
# (Degrees of freedom (+/- 180°) (actually possible for every drive))
 +
# Accessible for testing
 +
 
 +
 
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'''The 4 Differtent Drives'''
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'''Mechanical'''
 +
 
 +
Powerfull, but not sustainable and sharing energy enhances the risk of explosions.
 +
 
 +
 
 +
'''Hydraulic '''
 +
 
 +
Unlimited torque, but efficiency starts at high weight. Also extra weigth of the fluids.
 +
 
 +
 
 +
 
 +
'''Pneumatic '''
 +
 
 +
Good power/weight ratio, but low forces and hard to share energy.
 +
 
 +
 
 +
'''Electrical (Best suitable for our design)'''
 +
 
 +
The most suitable option. Powerfull and light.
  
  
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http://www.rcheliwiki.com/Power_to_weight_ratio
 
http://www.rcheliwiki.com/Power_to_weight_ratio
 
http://www.inmoco.co.uk/electro-mechanical_vs_pneumatic_actuators
 
http://www.inmoco.co.uk/electro-mechanical_vs_pneumatic_actuators
 +
 +
 +
----
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With the support of the Culture Programme of the EU.<br>
 +
[[File:EU_flag.jpg|420px]][[File:META_logo.jpg|420px]]

Latest revision as of 10:48, 23 March 2016


Motors & Sensors


Servo testing

Servo testing 250gr on 30cm arm. Testing the power demand.
http://re.hyperbody.nl/pdf/Film1.2.mp4
Servo testing 250gr on 40cm arm.
http://re.hyperbody.nl/pdf/Film2_2.mp4

6/5 computer, sensor and connection choices

1. One joint with sensor working
Raspberry pi/Arduino control motor with sensor


2. Two (Micro)Computers Communicating ethernet/bluetooth

3. Advanced control Consensus Algorithm

25/3 Adapt servos

IMG 2917.JPG

The brown wired element on the right is the potentio meter. That measures the angle of the output axle of the motor. The turning angle of the meter is limited to less than 360 degrees. So that causes a problem when putting any gears on that axle to increase torque. The meter has to be replaced to the good axle of the right measurements.

11/3 Type of Motor Decisions

Based on some requirements for the motor, the decision was made to use a Servo Motor, instead of a Stepper Motor or a DC Motor.

The requirements were the following:

  1. The position controllability of the axle of the motor
  2. A high power/weight ratio
  3. High accurately placed at a desired angle of the axle
  4. Being able to stall for some time
  5. Being low cost
  6. Availability of using a battery to power the motor


In the next 2 documents the decision of the Servo Motor is being explained further

[1]

[2]

5/3 Arduino testing

FullSizeRender.jpg Attempt to connect and control dynamixel 12a+

IMG 2840.JPG Dynamixel control module/chip sn74ls241

4/3 Drive

The most influential decision for the design of the joint is the way the joint is driven. In this document we argue the different drive and the best suitable on for our design needs.


Criteria for the drive

  1. Handle high torques/forces (or high speed with a gearbox)
  2. Power/weight ratio
  3. Accurately controllable
  4. Size
  5. Sharing energy
  6. Maintaining position
  7. (Degrees of freedom (+/- 180°) (actually possible for every drive))
  8. Accessible for testing


The 4 Differtent Drives

Mechanical

Powerfull, but not sustainable and sharing energy enhances the risk of explosions.


Hydraulic

Unlimited torque, but efficiency starts at high weight. Also extra weigth of the fluids.


Pneumatic

Good power/weight ratio, but low forces and hard to share energy.


Electrical (Best suitable for our design)

The most suitable option. Powerfull and light.


http://www.designnews.com/document.asp?doc_id=230452 http://en.wikipedia.org/wiki/Power-to-weight_ratio http://www.rcheliwiki.com/Power_to_weight_ratio http://www.inmoco.co.uk/electro-mechanical_vs_pneumatic_actuators


With the support of the Culture Programme of the EU.
EU flag.jpgMETA logo.jpg

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