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Questions tagged [design]

Mechanical, electronic or programmatic design of a robot.

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74
votes
4answers
12k views

Why are Mars rovers so slow?

Mars rovers are typically very slow. Curiosity, for example, has average speed of about 30 meters per hour. Why is it designed so slow? Is it because of some specific power restrictions or for other ...
21
votes
4answers
4k views

Why are quadcopters more common in robotics than other configurations?

I've noticed that almost all research being done with helicopter robots is done using quadcopters (four propellers). Why is there so little work done using tricopters in comparison? Or a different ...
20
votes
5answers
2k views

Is it better to have batteries distributed at the rotors or the center of the multicopter?

I've seen 3 approaches to mounting batteries on a multicopter: All the batteries rigidly mounted near the center of the airframe All the batteries in a bag hanging under the center of the airframe ...
17
votes
3answers
2k views

Why do Mars rovers designers prefer wheels over tracks?

Typically Mars rovers use wheels and not tracks. I guess Spirit would have better chances getting out of that soft soil should it have tracks. In general, Mars surface structure is not known in ...
17
votes
3answers
2k views

What is the best way to power a large number (27) servos at 5 V?

I apologize if this question may sound a little vague. I am working on a robotics project that will contain 27 servos of various sizes and I am having trouble figuring it how they should be powered. ...
16
votes
2answers
18k views

Wheels vs Continuous Tracks (Tank Treads)

I'm building a small robot using some cheap Vex Robotics tank treads. However, my choice of picking tank treads is almost purely based on the fact that they seem like more fun than wheels. I don't ...
12
votes
3answers
765 views

How can I control a fast (200Hz) realtime system with a slow (30Hz) system?

We are currently designing a mobile robot + mounted arm with multiple controlled degrees of freedom and sensors. I am considering an architecture in two parts: A set of realtime controllers (either ...
12
votes
2answers
914 views

Is it better to have weight distributed over the wheels or the center of the robot?

When designing a standard 4 or 6 wheel robot, is it better to have the weight distributed primarily in the center of the robot, or over the wheels, or is there no difference? Specifically, which ...
12
votes
3answers
8k views

Calculating the efficiency of Mecanum wheels

I'm part of a FIRST Robotics team, and we're looking into using Mecanum wheels for our robot. What are the advantages and disadvantages of using Mecanum wheel versus regular ones? From looking ...
12
votes
2answers
3k views

Differences between Ackermann steering and standard bi/tricycles concerning kinematics?

I got the following homework question: What are the general differences between robots with Ackermann steering and standard bicycles or tricycles concerning the kinematics? But, I don't see what ...
12
votes
3answers
8k views

When should FPGAs be used in Robotics?

FPGA has good points such as a lot of IO points but then again you need to think things on very low level with flip-flops and pioneer on areas where things are not yet mature -- for example see this ...
11
votes
1answer
1k views

Choosing the right dimensions for an underwater glider

I'm looking to potentially build an underwater glider, a type of submarine that's slow but can operate on extremely low power draw. However, in order for it to work effectively I've found several ...
9
votes
4answers
3k views

What are human-friendly terms for mobile-robot orientation and relative direction of non-robot objects?

Within robotics programming, orientation is primarily given in terms of x, y, & z coordinates, from some central location. However x, y, z coordinates aren't convenient for rapid human ...
8
votes
2answers
715 views

Are power and torque required related in some way?

I am designing a new platform for outdoor robotics and I need to calculate the power and/or torque that is needed to move the platform. I have calculated that I need about 720 W of total power to move ...
8
votes
2answers
789 views

Getting started with robotic arm design

I would like to design a robotic arm to hold a weight X at length Y (in my case I want to hold X=2.5 lbs at Y = 4 inches). Starting out simply, I would like try building an arm with a gripper plus one ...
8
votes
1answer
3k views

Building Robotic arm joint

I am very new to robotic design and I need to determine what parts I will need to assemble an arm joint. The joint will contain one timing belt pulley which a remote motor will be turning, a forearm ...
7
votes
2answers
4k views

How to know the desired orientation of a quadcopter?

I am trying to simulate a quadcopter model on Simulink. I want to implement a PID controller for each of X,Y,Z and phi,theta, psi angles. PID gets the error, as input, which is to be minimized. For ...
7
votes
2answers
3k views

Robotic part to dispense candy

I'm a complete newbie trying to build a simple robot that dispenses candy (M&M, skittles, etc). However, since I'm not familiar with the field, I'm having a hard time googling because I don't ...
7
votes
2answers
6k views

How do I motorize the elbow socket and other joints in a powered exo-skeleton?

How would you motorize the joints in an Iron Man suit? You need something fairly shallow, I would think, probably dual servos sitting on either side of an elbow or knee joint or either side of your ...
7
votes
3answers
2k views

How to open a sliding window?

I live in an apartment that has sliding windows in it. The apartment is naturally warm because we live above a mechanical room, such that we either opened the windows or ran the air conditioning ...
7
votes
1answer
1k views

MEMS accelerometer calibration

I am trying to calibrate a MEMS accelerometer. I was able to calibrate it for the current axis which is parallel to gravity and shows correctly, 1g. But the other two axes which should be 0.00g are ...
7
votes
2answers
268 views

Is there a tool for building and analysing robots (kinematics, control) visually?

I am reading research papers about robotics and many of them follow the same pattern: some construction is established kinematical formulas are read from the mechanical structure the state space is ...
6
votes
2answers
316 views

Drone targeting

Imagine a "drone" and a target point on a 2d plane. Assuming the target is stationary, there are eight parameters: ...
6
votes
1answer
681 views

What do quadcopter propeller specifications mean?

I'm trying to figure out the diameter of tri-blade propellers. I found a 7x3x4.5 blade, I'm trying to understand the measurements. Is the '7' the length of the blade giving the prop a 10.5" diameter? ...
5
votes
6answers
553 views

Effectiveness of a Mobile Robot In Relation To Mass

Do mobile and/or autonomous robots become more or less effective the bigger they get? For example, a bigger robot has bigger batteries, and thus bigger motors, whereas a smaller robot has the exact ...
5
votes
2answers
510 views

If you can create pure yaw motion with a quadcoptor then why won't this work with a tricoptor?

An answer to the question Why are quadcopters more common in robotics than other configurations? said: You need 4 degrees of freedom to control yaw, pitch, roll and thrust. Four props is ...
5
votes
1answer
479 views

Gears modeling in Google SketchUp and SketchyPhisics

I'm trying to make differential in Google SketchUp using this tutorial http://support.ponoko.com/entries/21249896-Gears-and-Joints-with-SketchUp-Sketchy-Physics for gears modeling. But I have problem: ...
5
votes
1answer
334 views

Dynamic braille interface

I'm a newbie in robotics, and I'm doing a project on dynamic Braille interface. Basically it's a 8*8 array of pins, which can be either totally up or down. How to use least motor as possible? I'm ...
4
votes
1answer
76 views

How important are events like “Robocup” to the advancement of Robotics in general?

Are events like Robocup advantageous to the development of robotic advancement? Or is it merely entertainment which advances robotics by allowing entry level participation which helps maintain ...
4
votes
1answer
438 views

How to get manufactured part from CAD file?

I am working through the book Learning Robotics using Python, which is for Python programmers who want to learn some robotics. Chapter 2 shows you how to use LibreCAD to design the plates and poles ...
4
votes
2answers
122 views

Air hockey with a robot as an opponent

I'm not sure if this is the right place to post this but here goes. So, as the title states, I'm planning on building a desk that doubles as an air hockey table which has a robot on the other side. ...
4
votes
2answers
68 views

How do I dispense a greasy fluid?

I'm a agricultural engineering student and complete newbie trying to build a simple mechanism attached to a drone that dispenses a grease-type fluid. However, since I'm not familiar with the field, I'...
4
votes
1answer
267 views

MCU architecture design

Are there any standards regarding single vs multiple MCU in a robotic system? More specifically, if a single MCU can handle all of the sensor data and actuator controls, is it better to use a single ...
3
votes
1answer
190 views

Can a state matrix have a row of zeros?

While formulating a state matrix of a system, say a system of a typical cruise controller, \begin{equation} \begin{bmatrix} \dot{v} \end{bmatrix} = \begin{bmatrix} -\frac{b}{m} \end{bmatrix} \begin{...
3
votes
1answer
655 views

Submarine screw and the isolation from the water [duplicate]

How does the submarine prevent water flow through the screw mechanism? The mechanism rotates the screw so there should be a little gap, how come the water doesn't come through this gap in to the ...
3
votes
3answers
1k views

How many amps do I want my Switching BEC to provide?

I'm trying to power 7-12 servos, and I was under the impression that each one would need about an amp, but in looking around for an appropriate BEC to supply them, I notice that most seem to output ...
3
votes
1answer
197 views

Is finished plywood a comparable prototyping substitute for polyoxymethylene?

I'm working on a robot with a team, and we're building our robot out of acetal polyoxymethylene (POM) (specifically, delrin) plastic. However, we'd like to prototype the robot before we build it out ...
3
votes
1answer
2k views

Alternative way to perform Pole zero cancellation?

I've read a lot places that making a controller which cancels the unwanted pole or zero is not good designing practice for designing a controller.. It should make the system uncontrollable which off ...
3
votes
2answers
2k views

Design Calculations & Mathematical Modeling of Tricopters

I have been studying about building a tricopter. But I couldn't find the design calculations or mathematical modeling of the tricopter any where over the internet. What are the mathematical ...
3
votes
1answer
820 views

Which is easier/cheaper: Hbridge vs ESC for controlling a motor?

I was able to find a small ESC for about $12 off of ebay. If you were designing a robot, would you see that and think? \$12 bucks for an ESC that connects to simple pulse-wave interface - sign ...
3
votes
1answer
165 views

Comparison of Balance Bot design

I'm planning to build a Balance Bot and I would like to know which design should I go with. There's a vertical design such as the ArduRoller and on the other hand, there's the typical stacked type of ...
3
votes
3answers
527 views

Atlas Robot Reference

Boston Dynamics keeps making great robots, however, I dont see any papers that they publish. Although now I can find papers on people using the ATLAS robot, I can not find an original paper detailing ...
3
votes
1answer
678 views

Rocker bogie suspension stability

From the designs usually shown of rocker bogie systems, the whole weight of platform seems to be supported by only one rod, be it differential bar or gear. Isn't this a bit unstable system because if ...
2
votes
5answers
539 views

Quadcopter frame design

Quadcopter frames seem to consistently follow the same X design. For example: I'm curious to know why that is. It certainly seems like the most efficient way to use space but is it the only frame ...
2
votes
1answer
133 views

Inverting a transform (Reading J Craig's book on Robotics)

From Introduction to Robotics by J.J. Craig, chapter 2, Page no. 36: Could anyone explain how that equation was derived/formed? I am stuck on this page due to failing to understand where the equation ...
2
votes
5answers
1k views

Why Make Bipedal Robots?

A friend and colleague of mine who studies robotics says that bipedal robots present much greater challenges for stability and locomotion than those with more legs. So why is there so much effort to ...
2
votes
2answers
60 views

Is it better to use software or hardware for object sorting?

For a sorting machine where the objects to be sorted have various sizes, color, shapes, and patterns, is it more optimal (in terms of minimal time of the overall process and maximal precision and ...
2
votes
1answer
744 views

What is torque bandwidth in actuated joints and how does it affect the control systems?

The rest of my student team and I are in the process of redesigning an exoskeleton and building it based on an existing one. From the papers that we have been reading there are some references to low, ...
2
votes
2answers
115 views

idea for web application in robotics [closed]

I am learning and I am interested robotics, but also I need to update my web development skills so the question is - is there any idea for good web application that could be connected with robotics - ...
2
votes
3answers
6k views

How to decide about the length of a robotic arm, the base of it and the torque?

I am designing a remote controlled robot which will have a base with three wheels, two of them will be simple wheels at the back of the base and the third will be a ball wheel at the front. It will ...