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Tigerbot P15201
Detailed Design Review
Mechanical
Torque Recalculations
● Added min and
max in walking
motion.
Servos and Motors Selection (Walking)
CAD Models
(Full Assembly)
CAD Drawings Cont. (Torso)
CAD Drawings Cont.
(Lower Body)
Lazy Susan Hip Design
Manufacturing
● Process
o
o
o
o
Get Stock Aluminum
Square it to dimensions
Bend into U bracket
Weld rod to 2 brackets (one on each side)
● *Welding Depends on Rob Kraynik(ME Shop
Machinist) schedule. Easy task to
accomplish; risk: lead time
Schedule (Manufacturing)
Testing Plans
● Torque Output:
o
Test the servo with the gear combination for the
required torque output.
● Degrees of Freedom:
o
Measure overall range of each joint
Electrical
Expected Power
Expected Power
We plan on using a fixed 48V 32A DC supply to test the design and gain an accurate measure of
current draw.
Our power draw estimates currently assume a 4A draw by the servos
For purely walking: Ptotal=20A at 48V= 960W | ~20A
For tour scenario: Pwalk= 20A at 48V = 960W | 8A
Pstand= 15A at 48V= 720W | 9A
Ptotal=60%Pstand+40%Pwalk=816W |~20A
Based on new information, our current draw will be less than 4A. Therefore our power required will be
less than the worse case, which is less than 960W.
If, we were to purchase a battery, our solution would be,
Wiring
●
●
●
●
8 AWG wire used for battery to distro board
8 AWG wire used from power supply to distro board (in place of batteries)
18 AWG wire used for servo power (distro to servo)
18 AWG wire used for servo control (microcontrollers to servo)
o 18 AWG chosen to fit MOLEX crimp pins for servo connections
● 28 AWG ribbon cable used for sensor wiring (power, data, I2C, etc.)
Servo Connections
● MOLEX Minifir Jr. series mates with Teknic servo power/control
connectors
o 4 pin for power
o 8 pin for control
Schematic
Refer to handout please
Custom PCBs
●
●
●
●
1 (x2) for FSR support circuitry
1 (x1) for servo power distribution
1 (x5) for ADC and support circuitry
8 total
Advanced Circuits offers 60 in2 of 2 layer board space for
$33 to students
Sensors
Force Sensing Resistor (FSR):
FlexiForce Sensors: A201- Connector 3-pin male square pin
Weight Range: 0-1 lb (4.4 N)
0-25 lb (110 N)
0-100 lb (440 N)**
**Weight range can be increased with the proper circuit layout
We used the recommended circuit in the spec sheet and modified it
Sensor
Sensor
Sensor
From the manufacturer
Sensor
RFID:
At this time we have decided to not choose a RFID
solution. Due to the scope of our project a RFID solution
will be generated if there is time available.
Sensor
Object Detection:
Parallax Ping Ultrasonic and Sharp IR:
We plan to use a combination of sensors for object
detection in the path of the robot. Ultrasonic will provide
long range and IR will provide close range detection.
Sensor
Sharp IR Distance Sensor - GP2D12 Alternative
Connector: 3 pin with analog output
Detection: 10-80cm.
Will require additional cable
Sensor
Parallax Ping Ultrasonic:
One of two options we are testing.
Connection: 3 pin bidirectional TTL
Detection: 0.02 to 3 m
Concern: Based on testing, it may not have a fast enough
response time. We are considering alternatives.
Sensor
25k Potentiometer
Use as simple position feedback for the servos
Item
Part
Description
Link/Manufacturer
Unit
Price
Quantit
y
Extended
Price
http://www.trcelectronics.com/View/Mean-Well/RSP-1500-48.shtml
$348.30
1
$348.30
E
1
Wired PSU
48VDC 32A servo
power supply
L
2
Pololu 5V PSU
5V regulated PSU
http://www.pololu.com/product/2851
$14.95
1
$14.95
E
3
Pololu 3.3V PSU
3.3V regulated PSU
http://www.pololu.com/product/2110
$14.95
1
$14.95
Ribbon Cable
http://www.newark.com/3m/3365-20/cable-ribbon-20cond-100ft28awg/dp/03F5908
$35.80
1
$35.80
$5.90
5
$29.50
C
4
3M 3365/20 20COND,
100FT, 28AWG, 300V
T
5
ADC128D818
12-bit ADC
http://www.digikey.com/productdetail/en/ADC128D818CIMT%2FNOPB/ADC128D818CIMT%2FNOP
B-ND/2262897
R
6
Custom Li-Ion Battery:
7.4V 6.6Ah
LiPo Battery for
Sensors
http://www.batteryspace.com/custom-li-ion-battery-7.4-v-6600-mah44.84-wh-battery-module-with-pcb.aspx
$58.90
1
$58.90
I
7
HIGH C-RATE LIPO
BATTERY
LiPo Battery for
Servos
http://www.bmsbattery.com/battery-pack/664-36v-12ah-38140lifepo4-battery-12-cells-ebike-battery-pack.html
$219.00
2
$438.00
C
8
25k Pot
Potentiometer
http://www.smallbearelec.com/servlet/Detail?no=688
$1.00
22
$22.00
Ultrasonic Sensor
http://www.parallax.com/sites/default/files/downloads/28015-PINGDocumentation-v1.6.pdf
$29.99
1
$29.99
$12.95
6
$77.70
A
L
9
Parallax PING)))
10
GP2D12 Alternative
(10-80 cm)*
Sharp IR Sensor
http://www.trossenrobotics.com/sharp-ir-distance-sensorgp2d12.aspx
11
Dev. board
RFID
http://www.digikey.com/product-detail/en/TRF7970ATB/296-31310ND/2833503
$50.00
1
$50.00
12
FlexiForce Sensors:
A201
Force Sense
Resistor
http://www.tekscan.com/flexible-force-sensors
$117.00
1
$117.00
13
Teensy Micro
Microcontroller
https://www.pjrc.com/teensy/
$15.95
5
$79.75
Micro USB-USB 2.0 Sync Data
14 Charge Cable
Wire
http://www.newegg.com/Product/Product.aspx?Item
=9SIA1UA1UH3571&cm_re=micro_usb_to_usb-_9SIA1UA1UH3571-_-Product
15
Wire
https://www.parts-express.com/jsc-wire-18-awgred-black-zip-power-speaker-wire-1-ft-usa--100-050
$0.31
340
$105.40
servo power connector
http://www.digikey.com/productsearch/en?x=0&y=0&lang=en&site=us&keywords=
39012040
$0.31
23
$7.13
servo control connector
http://www.digikey.com/productsearch/en?KeyWords=39012080&WT.z_header=se
arch_go
$0.45
23
$10.35
MOLEX crimp pin
servo crimp pin
http://www.digikey.com/productdetail/en/0039000038/WM2501CT-ND/467978
$0.10
300
$30.00
19
30A screw terminal
power distro screw
terminal
http://www.digikey.com/productdetail/en/8196/8196K-ND/316832
$0.79
4
$3.16
20
8 AWG
Wire
https://www.parts-express.com/jsc-wire-8-awg-redhigh-current-power-cable-1-ft-usa--100-178
$0.95
25
$23.75
7 Port USB 2.0 Hub
http://www.newegg.com/Product/Product.aspx?Item
=9SIA24G2179518&cm_re=usb_hubs_powered-_17-707-143-_-Product
$19.41
1
$19.41
Power wire
https://www.parts-express.com/carol-12-awg-3csjoow-power-cable-50-ft--100-578
$51.01
1
$51.01
$8.68
1
$8.68
$0.69
2
$1.38
16
17
18
21
22
18AWG
4 pin MOLEX connector
8 pin MOLEX connector
StarTech ST7202USB
50ft 12 AWG 3 conductor wire
23
15A industrial AC plug
Power connector
http://www.homedepot.com/p/Pass-Seymour-15Amp-125-Volt-Industrial-Grade-Straight-PlugPS5266XCCV4/202664475
24
TL074
General Purpose Op-Amp
http://www.ti.com/product/TL074/description
$0.98
10
$9.80
26
Resistors
1kOhm 0.25W
http://www.circuitspecialists.com/rc1000.html
$0.10
16
$1.60
27
Resistors
4kOhm 0.25W
http://www.circuitspecialists.com/rc4020.html
$0.10
8
$0.80
28
Resistors
10kOhm 0.25W
http://www.circuitspecialists.com/rc10k.html
$0.10
20
$2.00
$0.11
10
$1.10
$0.25
10
$2.50
29
Bypass Capacitor
Tantalum, 0.1 uf
http://www.taydaelectronics.com/capacitors/0
-1uf-35v-radial-tantalum-capacitor.html
30
Bypass Capacitor
Ceramic, 0.1 uf
https://www.sparkfun.com/products/8375
UPDATE:
Computer
Pandaboard
ROS for a Leg
Message Passing
ROS Stack
ROS Nodes
Work on ROS / CPU / Sim status
I2C - working!
IMU - interfaced and reading data
ROS - learned much, but still much to learn
Simulation - learning ros, we have simple moving models working.
Simulation - Currently working on interfacing controls, this will be applied to
tigerbot when more is learned.
Online teensy programming - works manually, working on automated script
ROS intro tutorial - DONE!
Teknic motor control update - Pulse Burst Positioning appears to be the best
control method, the desired distance (rotation) is proportional to the number of
pulses sent to the motor. 2 velocities can be preprogrammed.
Questions?