Embedded Motion Control 2017 Group 6

About the group

Name	Student ID	E-mail
Ties Hoenselaar	0857112	t.a.h.hoenselaar@student.tue.nl
Hasan Ilisu	0852221	h.h.ilisu@student.tue.nl
Laura de Jong	0743679	l.s.d.jong@student.tue.nl
Lars Moormann	0861223	l.moormann@student.tue.nl
Bas Straatman	0777325	s.r.t.straatman@student.tue.nl
Jeroen van der Velden	0744957	j.r.v.d.velden@student.tue.nl
Wouter Houtman	Tutor	w.houtman@tue.nl

Introduction

Robots Pico and Taco

The most memorable part of the course Embedded Motion Control is the 'A-MAZE-ING PICO' challenge, in which software is designed for and implemented into autonomous robots. These autonomous robots, called Pico and Taco, should then be to able to solve a maze with the software in a real-life environment. A maze can contain loops, dead ends, open spaces and doors that automatically open and close.

Pico will be provided with a basic software layer to carry out primary functions, such as communication and movement. However, to succesfully complete the 'A-MAZE-ING PICO' challenge it is required to design robust software for the changing environment. Several software subsystems will be put to the test in an intermediate challenge. During this challenge, called the corridor competition, Pico must move through a corridor and take the first exit. With the results of the corridor competition and all its software subsystems Pico should be able to finish the maze challenge. The course Embedded Motion Control is concluded with an overall conclusion.

Software design

The ever-changing environment in reality requires the design of a robust software architecture. It is prefered to design this software architecture before actually programming, because it gives a clear understanding/agreement of the different functions from the start. The first step in creating the software architecture is to mention the requirements that have to be met in order to complete the corridor competition and the maze challenge. Pico should be able to finish these challenges succesfully by using most of its components. Secondly, a list of specifications will be given to accuratly describe the robot, corridor and maze. With these requirements, components and specifications it is then possible to define functions for the software architecture. The software architecture is completed by specifying the interface between these different functions.

Requirements

To complete the corridor competition and maze challenge Pico has to meet the following requirements:

• Operate fully autonomous
• Avoid collisions with walls
• Robust against sensor disturbances and layout imperfections
• Update, compile, start and end software with single commands
• Corridor competition
  • Move through a corridor that complies with the specifications
  • Exit the corridor within the set time limit
  • Recognize junctions
• Maze challenge
  • Move through a maze that complies with the specifications
  • Escape the maze within the set time limit
  • Recognize junctions, loops, dead ends and doors
  • Ring the bell at dead ends and doors
  • Stand idle for a certain period of time
    

Components

The following components of Pico will be used to fulfill the requirements:

• Sensors
  • Laser range finder (LRF) determines the distance to an object with a laser beam
  • Wheel encoders (odometry) determine the position of Pico relative to a starting position
• Actuators
  • Holonomic base with three omni-wheels to drive and turn
  • Bell to request a door to open
• Computer
  • Intel I7 processor
  • Ubuntu 14.04 as operating system
    

Specifications

Pico, the corridor competition and the maze challenge are characterized by the following specifications:

• Pico
  • Dimensions of 42 cm x 40 cm x 108 cm (LxWxH)
  • Maximum translational speed of 0.5 m/s
  • Maximum rotational speed of 1.2 rad/s
  • Maximum amount of bell actions equal to the amount of doors plus dead ends
  • Maximum idle time of 30 seconds
  • LRF
    • Located at ??
    • Range of ??
    • Horizontal field of view of 270°
    • Frequency of ??
    • Accuracy of ??
  • Odometry
    • Located at ??
    • Resolution of ??
    • Frequency of ??
    • Accuracy of ?? (negligible compared to the slip of the omni-wheels)
• Corridor competition
  • Maximum of two attempts within 5 minutes total
  • Penalty of 5 seconds or 1 attempt when slightly touching or bumping a wall
  • Corners are approximately 90°
  • Walls are approximately parallel to each other
  • Distance between walls can range from 0.5 to 1.5 meter
  • Distance from start to finish is between 1 and 10 meters
  • Start is located between the walls in the main corridor
  • Finish is located 0.3 meter inside a side corridor on either the left or right
  • Main corridor has open ends
• Maze challenge
  • Maximum of two attempts within 7 minutes total
  • Penalty of 5 seconds or 1 attempt when slightly touching or bumping a wall
  • Corners are approximately 90°
  • Walls are approximately parallel to each other
  • Distance between walls can range from 0.5 to 1.5 meter
  • Distance from start to finish is unknown
  • Start is located inside the maze, but outside a door area
  • Finish is located on the boundary of the maze behind a door
  • Can contain loops, open spaces and more than one dead end
  • Contains one door and it is located at a dead end
  • A dead end is between 0.5 and 1.5 meter wide and at least 0.3 meter long
  • A door area is located in front of a door and is 1.3 meter long
  • Door opens when Pico is inside the door area, stands still and sends a request
  • Door starts opening within 2 seconds and is fully opened within 5 seconds
  • Door opens to the left or right with approximately constant velocity
    

Functions

The requirements can be met with the given components and specifications by defining various functions for the software architecture. These functions typically use sensor information to determine the next actuator action, or compute a variable that is used by another function. When defining functions it is important that each function has a single and clear purpose. All the functions that are required to complete the maze challenge are visualized in a function flow chart. The colors in the function flow chart indicate how much functionality of that function is needed to finish the corridor competition.

However, to complete the corridor competition only the functionality of the green functions and partial functionaility of the orange functions are required. This approach saves time because every function used for the corridor competition is reused for the maze challenge. The function flow chart is run through every iteration, and based on the setting of the state machines a different part of the code is executed.

Function flow chart

Interfaces

The main relations between the interfaces are colored red and can be described as follows:

World model -> Task:The world model can give information about taken paths to the Task
World model -> Skill:The stored observations in the world model are used for movement skills
World model -> Motion:The world model can give data to the actuators
World model -> User interface: The user interface needs the data from the world model to visualize the world model to the human
Task -> World model:The task needs to store information about paths in world model
Skill -> World model :The world model is build from observations
Motion -> World model :The motion can give sensor data about the position to the world model

File:Initial design plan EMC group 6.pdf

Corridor competition

During the corridor competition on the 24th of May Pico had to move through a corridor and take the first exit. The dimensions of the corridor and location of the exit were determined by the organisation and coin flip, respectively. For this intermediate challenge only

Corridor competition first attempt

Corridor competition second attempt