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Wheatley - Process

General timetable

 

At the beginning, various ideas were contributed by means of brainstorming. These were sorted into a morphological box and the best suggestions were combined into three concepts. The individual subfunctions were tested during the trial week and then a main concept was created.

 

Concept 1

Forklift like mechanism

 

Concept 2

Electromagnet on spindle

 

Concept 3

Snap gripper

 

Morphological box

Our ideas

We wanted to make our robot as simple as possible. This allows us to concentrate better on the sub-functions and minimizes the risk of overlooking something. 

We decided on a round base plate. The roof is held in place with the help of rods. 

The robot «Wheatley» from the game Portal served as a model, especially for our special feature the sound output.

 

Lifting system

A height of 180 mm must be reached, and the robot must not exceed 160 mm. A toothed rack was used for this purpose. Together with a motor, a guide rod and the electromagnet attached to it, this forms the lifting system. 

Drive unit

The chassis consists of two wheels, two motors and two ball casters for stabilization. The playing field is marked with black lines, which the robot uses for orientation. This orientation is achieved by means of infrared sensors, eight of which are attached to the underside of the robot. In addition, the robot is equipped with two stop sensors at the front. These are used for more precise positioning in front of the components.

Layout

The entire electronics of the robot are located on a print. The round base and the lifting system give it a rather unusual shape. In terms of space, everything was kept very compact by equipping the print on both sides. The motor drivers are on the front right, the electronics for the infrared sensors are on the back right. The 3 different supply voltages are generated at the rear left and the remaining sensors, actuators and the WLAN module are controlled at the front left. The Zynq is the heart of the robot and was thus placed in the center of the print.

Component detection

Walls are detected by means of an Autosen A0024 type diffuse sensor. There are three different wall types - a door, a window and a glass front (see Figure 6). These are distinguished by the number of openings at a certain height. The sensor counts the rising edges and can thus distinguish the components. The number of edges counted is displayed by means of LEDs on the cover plate of the robot.
The roofs can only be detected with a camera. This task is performed by the partner robot, as only this is equipped with a camera.

Positioning on the playing field

In order for the robot to be able to orient itself on the lines on the playing field, eight infrared sensors of the type VISHAY TCRT1000 are used to evaluate the light reflected from the bottom of the IR LED with a phototransistor. For this purpose, the template of the specialist course was used as a template for the newly designed circuit. The control of the IR-LED's and the phototransistors of the infrared sensors is controlled by the Zynq7000.

Flowchart

The flowchart shows the process of our robot.

The robot was programmed according to this diagram.

Structure of our program and its tasking system.

 

Hardware

 

33.33 MHz oscillator
1 GB of DDR3 SDRAM
128 Mb of QSPI Flash
Micro SD card interface
10/100/1000 Ethernet
USB 2.0
USB-UART
100 User I/O (50 per connector)
Configurable as up to 48 LVDS pairs or 100 single-ended I/Software