Difference between revisions of "Raspberry PI Spiderbot"
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{| class="wikitable" | {| class="wikitable" | ||
|- | |- | ||
− | ! ServoId !! Leg !! Extrimity !! Inverted | + | ! ServoId !! Leg !! Extrimity !! Inverted |
|- | |- | ||
| 0 || 1 || Coxa || | | 0 || 1 || Coxa || | ||
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|- | |- | ||
| 11 || 1 || Tibia || | | 11 || 1 || Tibia || | ||
+ | |- | ||
+ | |} | ||
+ | == Calibration Range == | ||
+ | {| class="wikitable" | ||
+ | |- | ||
+ | ! Extremity !! Pos !! Direction !! Range | ||
+ | |- | ||
+ | | Coxa || 90 = 45 || left to right || 0-180 | ||
|- | |- | ||
|} | |} |
Revision as of 10:24, 19 January 2020
OsProject | |
---|---|
id | PI-Q-Robot |
state | |
owner | BITPlan |
title | Raspberry PI controlled Quadruped Robot with 3D Simulator |
url | https://github.com/BITPlan/PI-Q-Robot |
version | 0.0.1 |
description | |
date | 2019-08-07 |
since | |
until |
Click here to comment see Self Driving RC Car
Inspired by the Arduino Project below we'd like to create a Raspberry PI version as in https://github.com/yasaspeiris/aragog
Video
Simulator
Calibration
Restful interface
http://<baseurl>/servo/<servoid>/<angle> will set the angle of a single servo
Servo numbering scheme
This is the default numbering schema as configured in the software. If your servos are mounted or cabled differently you might want o adjust the code a accordingly
ServoId | Leg | Extrimity | Inverted |
---|---|---|---|
0 | 1 | Coxa | |
1 | 1 | Femur | |
2 | 1 | Tibia | |
3 | 2 | Coxa | |
4 | 2 | Femur | |
5 | 2 | Tibia | |
6 | 3 | Coxa | |
7 | 3 | Femur | x |
8 | 3 | Tibia | |
9 | 1 | Coxa | |
10 | 1 | Femur | x |
11 | 1 | Tibia |
Calibration Range
Extremity | Pos | Direction | Range |
---|---|---|---|
Coxa | 90 = 45 | left to right | 0-180 |
Relevant source code
class Spider:
""" I am a quadruped spider with four legs consisting of coxa, femur and tibia each"""
def __init__(self):
self.fl = Leg(0, 0, 1, 2)
self.fr = Leg(1, 3, 4, 5)
self.rl = Leg(2, 6, 7, 8)
self.rr = Leg(3, 9, 10, 11)
...
class Leg:
""" I am a single leg of the spider consisting of coxa, femur and tibia"""
def __init__(self, legId,coxaId, femurId, tibiaId):
self.legId=legId
self.coxa = Extremity('coxa', coxaId)
self.femur = Extremity('femur', femurId,legId>=2)
self.tibia = Extremity('tibia', tibiaId,legId>=2)
...
class Servo:
""" I am a single Servo motor """
def __init__(self, id,inverted=False):
self.id = id
self.inverted=inverted
def setAngle(self, angle):
self.angle = angle
trueAngle=180-angle if self.inverted else angle
if kit is not None:
kit.servo[self.id].angle = trueAngle
return trueAngle
Links
- Spider robot(quad robot, quadruped)-MG90 regishu 2017
- https://github.com/regishsu/SpiderRobot
- https://www.hackster.io/yasaspeiris/raspberry-pi-powered-quadruped-bbb68b
- https://github.com/yasaspeiris/aragog
- https://engineering.tamu.edu/media/4247823/ds-servo-mg90s.pdf
Other
Parts
# | picture | part | example sources | documents | ~ price | |
---|---|---|---|---|---|---|
1 | Raspberry PI 3 B+ | Raspberry PI 3 B+ | en | 35 € | ||
2 | microSD Card | SanDisk 16 GB | 7 € | |||
3 | Raspberry PI Camera | 1080 p Camera Module | 23 € | |||
4 | DC/DC Converter 12 V-> 5V | 12 V->5 V Converter Module | 7 € | |||
5 | Micro USB Connector | Delock USB 2.0 Micro USB | 6 € | |||
6 | 3D Printed Parts: Coxa, Tibia, Femur, Hinge | parts from regishu's design | ||||
7 | Adafruit PCA9685 16 channel PWM controller | PCA9685 | 6.5 € | |||
8 | set of small screws | set of small screws | 8.5 € | |||
9 | 12 x MG90S | 12 x MG90s | 42 € | |||
Total | ~ 135 € | |||||
a | Breadbord Kit | MB102 Breadbord Kit | 7 € | |||
b | Ulrasound Sensor | 5 x HC-SR04 + Cables | 10 € |
Printing
You might want to make sure that you print your parts with sufficient infill - I used 75%.
Example for broken part
This part was printed with Cura's default infill and broke off:
Assembly
- Legs and hinges are connected with 1.4x5mm screws
- Legs and servos are connected with 1.7x6mm screws
We use the raspberry base from https://github.com/yasaspeiris/aragog/blob/master/3d%20printed%20parts/base.STL
Leg Test
sudo python3 testadafruit.py 0 1 2 3 0
sudo python3 testadafruit.py 0 1 2 3 90
sudo python3 testadafruit.py 0 1 2 3 180
testadafruit.py
# Test Adafruit
# WF 2019-07-09
import sys
import time
from adafruit_servokit import ServoKit
kit = ServoKit(channels=16)
#
# set the given angle for the given servos
#
def setAngle(servos,angle):
print (angle)
for id in servos:
kit.servo[id].angle=angle
time.sleep(0.3)
# Test Servo Software
servos=[]
args=len(sys.argv)
fromangle=0
toangle=180
step=1
if args>1:
for port in range(1,args-1,1):
servos.append(int(sys.argv[port]))
anglestr=sys.argv[args-1]
if "-" in anglestr:
parts=anglestr.split("-")
fromangle=int(parts[0])
toangle=int(parts[1])
else:
fromangle=int(anglestr)
toangle=fromangle
else:
servos.append(0)
servos.append(1)
servos.append(2)
if fromangle!=toangle:
try:
while True:
for setangle in range(fromangle,toangle+step,step):
setAngle(servos,setangle)
except KeyboardInterrupt:
print("Keyboard interrupt")
else:
setAngle(servos,fromangle)
Evolution of Base
Since we'd like to use a Raspberry PI we couldn't use the orignal Base by regishu. Trying the one from https://github.com/yasaspeiris/aragog also did not work since our raspberry PI case had a different size. So incrementally a new design was created:
The problems mentioned further below led to this design:
Legtest 2
The three parts of a leg have been connected to the ports 10,11 and 12 and then the test was started with:
sudo python3 testadafruit.py 10 11 12 60-120
Wiring
Breadboard - style wiring before designing a proper holder:
In this state of affairs:
- the power input of the raspberry is blocked by a servo - needs to be moved by at least 13 mm
- the corner hinges are to close to the corners of the servo holders
- the pivots to be used for the next level are blocking e.g. the usb connectors