AMIGO Base

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TU/e
CST Group, TU/e
rop@tue.nl
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STEP
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(Coming Soon)

AMIGO: Head | Arms | Torso | Base


Contents


Part Summary

The base acts as the support structure for AMIGO. It provides space for important hardware for the platform like the PC's, batteries, laser range finder and the wheels.

Overview

Under Construction
Figure 1 shows the CAD model of the fully assembled base.

Figure 1: Assembled base of AMIGO.


Mechanics

Omniwheels

Custom made omniwheels are used for Amigo. An exploded view of the wheel is depicted in figure 2. The wheel has a diameter of 150 mm. Ten small rollers (2) are positioned around its perimeter. Each of these rollers is fitted with seven O-rings. These provide the grip. The O rings vary in diameter. (Inner diameter 24 mm, 23 mm, 21 mm, 18 mm) They all have the same thickness (5 mm). The small rollers are relatively large. This allows higher obstacles to be crossed. The diameter of the wheel gives the platform a ground clearance of approximately 40 mm. Two needle roller bearings (INA HK0609) are placed inside each roller to ensure smooth rolling. The axles of the rollers are clamped between the outer rings (1) and (6) and the inner rings (3) and (5). Countersunk M4 bolts (4) are used to bolt the rings together. Both sets of wheels are aligned on the main hub (1) to which one of the outer rings already is attached. 5 M5 bolts (7) are used to bolt the second set of wheels to the main hub. The blue rings at the outside of the rollers are M6 shims with a thickness of 0.5 mm. All components of the wheel are made of aluminum. Technical drawings of the wheel are also provided.

Figure 2: Exploded view of a omniwheel.


Base Plate

Figure 3 shows the base plate of Amigo. It is a milled aluminum part. The main part (1) consists of a bottom plate and raised edges at the perimeter of the plate. The plate has a thickness of 5 mm and the raised edges are 25 mm high. The wheel protectors (2) are bolted to the raised edges. The same holds for the round edge protectors (7). Blocks (3) and (4) are used to clamp the batteries to the base plate. Blocks (3) are part of (1), so they are milled from the same piece of aluminum. Blocks (4) are loose parts, which are bolted to blocks (3). The design of the battery clamps is not completely finished yet. The electronic connector is not in it. The mounting point for this is not designed yet. But it is intended to be equal to the mounting point in the Turtle.


Figure 3: The base plate of Amigo.


A hole (5) is made in the centre of the base plate. This hole provides access to the tooth belt. The hole is covered from the bottom side by a 2 mm aluminum plate that is bolted to the base plate with counter sunk M3 bolts. The array of holes (6) is used for cooling of the PC which is positioned above it. Air can flow through the hole into the PC.


= Electronic Components Mounted on the Base Plate

Figure 4 shows the electronic components that are mounted on the base plate. The components are: 1. The batteries 2. Industrial Beckhoff PC with its stock mounting plate and a support unit that is used to connect it to the base plate. 3. Ethercat stacks. The lower one has it own support, which is similar to the support of the PC. The upper one is mounted to the PC support. The height of these stacks is not determined yet. In the design they have both the size of the stack that is used in the Turtle. 4. Amplifiers for the motors that drive Amigo around 5. Amplifier for the lifting mechanism. 6. Two traco power DC/DC 20 watt power converters + mount 7. Two Traco power DC/DC 150 watt power converters 8. LRF tilting mechanism and support. The support is folded from a 3 mm aluminum sheet and is bolted to the base plate.


Figure 3: Electronic components that are mounted on the base plate.

Electronics

(Coming Soon)

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