wheel vehicle in the 20+ kg class
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A home-made large radio controlled electric
wheel vehicle in the 20+ kg class |
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Back to Stefan's Some technical projects page
Report by Stefan Spännare, May 2009, updated September 2009
Note, print this web-page in landscape mode if it doesn't fit into portrait A4.
i. Warning
1. Introduction
2. Some information about the vehicle
Updated!
3. Components and prices for the vehicle
4. Some images (photos) of the vehicle rev. 1.0
5. Some images (photos) of the vehicle rev. 1.1
New!
6. A short video of the vehicle climbing grass and hills
New!
7. References
The author makes no warranties that this document is free of errors.
Be very careful to connect the lead accumulators with correct polarity to the
i. Warning
speed controller and the servo. It is also very wise to have fuses between the
accumulators and the electronic devices.
Sometimes I get the question why I make these technical projects and constructions.
The reason is that I find it fun and interesting. As usual the challenge lies in to make
the whole thing work. Then perhaps it is not used so much.
The vehicle is based on an electric scooter chassis and a worm geared electric
motor (24 V, 150 W) with two air pumped wheels (200 mm) sitting quite close
to each other (without differential). Thus the vehicle needs some auxiliary
small wheels (one at each side) for the balance. Perhaps this sounds like a bad
idea, but it works fine and the vehicle can take curves very well. This thing
is not exactly a "speed-monster". The top speed is about 5.2 km/h (walking
speed). Actually it would be nice if it could run two times faster. But it
is strong and can climb hills quite well. The length of the vehicle is 90 cm
and the total weight is about 24 kg. The scooter front wheel is steered by a
powerful servo (6 V, 42 kgcm). The servo has it's own small lead accumulator
(6 V, 4.5 Ah) and a fuse 10 A slow. The main motor and the speed controller
(32 cells 1.2 V, 40 A) has two lead accumulators (12 V, 7.2 Ah) connected
in series and a fuse 15 A slow. The radio is a cheap two channel stick radio
AM at 40 MHz.
More information is found in the table and images in the next sections.
The total price for the R/C vehicle (including radio) is about 3900 SEK or
$ 490. The prices below are given in SEK (May 2009) including VAT (25 %)
but no delivery costs. These shops are found in Sweden. Note, I think the
the speed controller and radio were bought already 2005 and 2006 to these
prices. Some bolts, nuts cables and fuse holders are not included in the price
(not so expensive).
| Nr | Component | Company | Article nr | Price per item (SEK) | Price (SEK) |
| 1 | Electric scooter chassis [1] | ? | ? | 0.00 | 0.00 |
| 1 | Worm gear motor (24 V, 150 W, 2500/139 rpm, 18x) [2] | Tradera | ? | 500.00 | 500.00 |
| 2 | Lead accumulator (12 V, 7.2 Ah) | Biltema | 80-410 | 179.00 | 358.00 |
| 1 | Lead accumulator (6 V, 4.5 Ah) | Biltema | 80-402 | 75.00 | 75.00 |
| 1 | Jaguar two channel stick radio AM at 40 MHz with receiver | Skånehobby | ? | 630.00 | 630.00 |
| 1 | Aero-Naut Multi 40 7019/72 (32 cells 1.2 V, 40 A) speed controller [3] | Skånehobby | ? | 1290.00 | 1290.00 |
| 1 | GWS S777/6BB servo (6 V, 42 kgcm) [4] | Lawicel | POL-0516 | 838.00 | 838.00 |
| 1 | Aluminum sheet (400 x 250 x 2.0 mm) | Clas Ohlson | 30-6351 | 99.00 | 99.00 |
| 1 | Two small auxiliary wheels with mounting | Bike shop in Lund | ? | 99.00 | 99.00 |
| Price total (SEK): | 3889.00 |
[1] The electric scooter chassis was found in the electronics recycle bin where I live.
[2] The worm gear motor was bought second hand on Tradera in Sweden. The motor comes with the wheels mounted on the axis.
[3] The speed controller can probably not be bought from Skånehobby any longer. See the Aero-Naut home page for more information.
[4] Lawicel in Sweden can take home these servos from Pololu.
1. Overview 1.
2. Overview 2.
3. Overview 3 from above. Servo, lead accumulators and speed controller
4. The large servo (6 V, 42 kgcm) and the radio receiver.
5. Lead accumulators and the very small powerful speed controller (32 cells, 40 A).
6. The front electric scooter wheel with steering bar.
7. The front wheel again and the large servo (6 V, 42 kgcm).
8. One of the auxiliary wheels (for the balance).
9. The main worm gear motor (24 V, 150 W) with wheels.
10. The main worm gear motor (24 V, 150 W) with wheels seen from behind.
11. The information sign on the worm gear motor.
12. The Jaguar two channel stick radio at AM 40 MHz.
Updated!
During September 2009 the vehicle was somewhat updated. It was
equipped with a smaller front wheel (to not stress the steering servo so much)
and the mid part of it was shortened 11.5 cm to make the vehicle more compact
and to make the turning radius somewhat smaller.
1. Overview.
2. Front part of the vehicle with the smaller front wheel.
3. Rear part of the vehicle.
4. The shortened mid part of the vehicle from above with steering servo,
radio receiver, lead accumulators and motor speed controller.
5. Front part of the vehicle from above.
6. Rear part of the vehicle from above.
7. The rear part of the vehicle with worm gear motor and wheels.
New!
This video of the vehicle (rev. 1.1) was taken in September 2009.
The sound of the video was removed because of to much talk on it.
A much better video of the vehicle will come soon.
Some useful Internet links: