BiPed Robot V-3

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The BiPed robot V-3 was designed to get as close to the freedom of movement of the human lower body, it has 12 degrees of freedom. The frame is made of acryl-sheets and model servos are used as actuators.

For now the robot is controlled via PC, autonomous behaviour when development finished. The software allows to generate motion-patterns, replay them and view actual sensor data.

Used sensors are a two-axis accelerometer for the orientation of the hip and four force-sensing resistors at the bottom of each footplate. A kind of torque feedback of the servos is realized by measuring the driving signal of the servo motor.

Further information at www.austrobots.com.

Step 1: Framework

The framework is made of acryl sheets. The parts get cut by a CNC milling machine, the first parts for testing were cut with a fretsaw.

The actuators integrated in the framework are servos used in RC-modeling. In general one servo is responsible for one degree of freedom. For a better mechanical stability two servos (at the top) are combined for lifting each leg. The servos actuating the footplate are working parallel.

Step 2: Electronics

Two types of ATMEL AVR controllers are used in the actual version, one mega8 as master and three tiny26 for servo-controlling, force-sensing resistor measurement and TFB-feedback. The master handles the data-transfer for each µC via I2C bus and the communication to the PC is realized as simple RS232 communication.

The "torque" feedback measurement samples the internal control signal of the servo motors and delivers information of the load to keep the desired position.

With the four FSR's on each footplate it is possible to measure if the robot is still in balance while standing on one foot. If the center of gravity is within the footplate the robot is stable.

All sensor data is visualized in the software.

Step 3: BiPed Control Software

With this VisualBasic program it is possible to generate motion patterns by using the slidebars to control the positio of each servo. By pressing a button the positions are stored in a file and may be replayed at different speed grades and interpolated servo positions.

The circle at the right visualizes the data of the accelerometers. If the hip is in a straight orientation the red circle is located in the center. Leaning the robot forward moves the red circle to the front.

The same principle for visualizing is used for the sensors in the footplates. Any unequally distposition of the robots weight, while standing on one foot, results in a displaced red circle.

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    41 Discussions

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    StevenG68

    2 years ago

    What force sensing resistors did you use? I've been doing a little work with them and finding that getting a consistent reading with them is a little bit of a challenge.

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    MohitJindal

    5 years ago on Introduction

    I am planning to buy a new DC motor driver board which can run 5amp motor but I don't know how to connect it with Atmega 8A chip. Please see the pdf I attached for Atmega 8A.

    Here are the 7 pins in DC motor controller:-

    Pin No. Pin Functionality
    1 GND Ground
    2 IN-1 Logic input for the motor direction.
    3 Diagnostic 1
    (DG-1) Output pin with logic 1 output in normal operation. Represents side of the internal
    H bridge corresponding to IN-1. Pin is pulled to logic low by the motor driver in
    case of over temperature or overload due to short circuit.
    4 PWM Used to apply Pulse Width Modulation to control motor velocity
    5 Diagnostic 2
    (DG-2) Output pin with logic 1 output in normal operation. Represents side of the internal
    H bridge corresponding to IN-2. Pin is pulled to logic low by the motor driver in
    case of over temperature or overload due to short circuit.
    6 IN-2 Logic input for the motor direction.
    7 CS* Current Sense output to measure the current flowing through the driver

    lol yeah, but if there were a pilot maybe controlled kinda like in teh avatar movie... it could be possible some day.

    addtionally to that, there would be too much maintenace necessary to make it an effective design during "in-field" use. at the present time this concept (the walker in general) presents too many complexities and complications, and is easily superceded by its wheeled counterparts, due to the relative ease of maintenance, and lack of complexity.

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    Derpancakes

    7 years ago on Introduction

    Ummm...... Why are you posting this instructable? This is a kit that you can buy... not something you just create... Also, I saw the main picture... in a book about buying robots.. Plz don't post a kit as something you designed

    1 reply
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    alex.vDerpancakes

    Reply 7 years ago on Introduction

    You are right, you saw the main picture in a book from Daniel Ichbiah (ISBN3896602764, german ed.) because I provided it. Why should he mention my name in the paragraph next to the picture ?

    Your false accusation is incredible ! Why don't you simply ask before writing such nonsense !

    However, would be nice If you could tell me where I am able to buy a kit of my robot ... possible because the design exists since 2001 ...

    I'm not being a "knowitall" but look up military walker suit on google. they have made a suit to wear that can lift thousands of pounds.(=