All Questions

12
votes
5answers
2k views

Starting out advice on making robots and tinkering with microcontrollers [closed]

I'd like to start making robots and tinkering with microcontrollers. Where do I start, and what do I need? I'd like to make my own robots. I'm comfortable with programming (assembly and C) so I've ...
23
votes
5answers
6k views

How can I integrate a smart phone with my robotics project? [closed]

Smart phones these days typically come with a gyroscope, accelerometer, compass, camera, and GPS sensor all on board. They also usually have a connection to the internet with Wifi and mobile data ...
15
votes
3answers
4k views

How can I automatically adjust PID parameters on the fly?

I have a simple servo system that uses a PID controller implemented in an MCU to perform the feedback. However, the properties of the system change dynamically, and so the PID parameters can never be ...
14
votes
3answers
476 views

How to determine quality of ICP matches?

In SLAM frontends which use the Iterative Closest Point (ICP) algorithm for identifying the association between two matching point clouds, how can you determine if the algorithm is stuck in a local ...
13
votes
2answers
4k views

Creating a fast, uniform, linear actuator

Most of the linear actuators I've seen are nonuniform and/or slow. Those using a cam or crankshaft-like mechanism (and nearly anything hydraulic/pneumatic) cannot be moved at a constant speed without ...
5
votes
3answers
308 views

Robotics Trends

Robotics has always been one of those engineering fields which has promised so much, but is taking a long time to deliver all the things that people imagine. When someone asks: "How long before we ...
2
votes
1answer
486 views

Suitable control algorithm for Air Muscle based joint?

I have a joint actuated by an antagonistic pair of Pneumatic Muscles. There are two valves per muscle, one to fill and one to empty each muscle. The joint has an angle sensor, and each muscle also ...
8
votes
1answer
728 views

HMMs vs. CRFs to model time-series force data of robots interacting with environment?

I have a time-series of force data of robots interacting with environment objects with various textures. I would like to develop models of various textures using the time-series data to classify ...
23
votes
9answers
13k views

Absolute positioning without GPS

Using an IMU a robot can estimate its current position relative to its starting position, but this incurs error over time. GPS is especially useful for providing position information not biased by ...
48
votes
9answers
178k views

What are good strategies for tuning PID loops?

Tuning controller gains can be difficult, what general strategies work well to get a stable system that converges to the right solution?
16
votes
2answers
6k views

How to choose a good IMU for a wheeled robot?

At our lab, we have a several "Kurt" type robots (about the size of a Pioneer, six wheels, differential drive). The built-in gyroscopes are by now really outdated; the main problem is that the ...
11
votes
4answers
9k views

Fixed point arithmetic on microcontrollers

Often we use microcontrollers to do things in our robots, but need to make some calculations in decimal. Using floating point variables is very slow, because a software floating point library is ...
34
votes
11answers
41k views

Preventing leaks in motor shafts for underwater bots

Whenever building an aquatic bot, we always have to take care to prevent leakages, for obvious reasons. Now, holes for wires can be made watertight easily--but what about motors? We can easily seal ...
7
votes
1answer
483 views

Detect Nao robot in Kinect

I am not sure if this has been tried before but I am trying to use Kinect and detect gestures made by the Nao robot. I have made a Kinect application, a gesture based picture viewer and it detects ...
8
votes
2answers
1k views

What rail material is best used for linear bearings?

For the 3d printer RepRap Prusa there are several rails (smooth rods) that guide the printer head on the different axises. The printer head uses several linear bearings to glide along the rails. ...
11
votes
2answers
9k views

How do I calculate the required loop frequency for a servo controller?

I have a motor which drives a string connected to a load cell. I would like to implement a closed loop controller to control the load applied by the motor to the string. How do I go about determining ...
6
votes
1answer
3k views

Technology behind Kiva Systems mobile robots

What kind of sensors and algorithms are the mobile robots of Kiva Systems equipped with?
14
votes
5answers
5k views

Mathematical prerequisites for beginning graduate student in robotics

A beginning graduate student in robotics asked me the areas of mathematics that he should brush up on (prerequisites) to begin a masters research program in robotics. What are some good materials/...
2
votes
3answers
712 views

Connecting two microcontrollers using I2C [closed]

I Have an ATmega16 mc which is master on the i2c and a ATMega8 mc which is slave on the i2c. I have connected the two mcs' sda and scl ports to each other alongside a pullup resistor. Now I want to ...
20
votes
10answers
4k views

How mature is real-time programming in robotics? [closed]

Edit: I don't know why, but this question seems to be confusing many people. I am aware of when/where/why/how to use real-time. I am interested in knowing whether people who have a real-time task ...
12
votes
2answers
869 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 ...
8
votes
1answer
863 views

Properly flashing the firmware on a Lego Mindstorms NXT

I am attempting to upload a custom firmware to a Lego Mindstorms NXT and am having issues. First of all, I'm attempting to use nxtOSEK, which would let me run C++ programs on it. The problem is, ...
4
votes
5answers
651 views

What is the difference between 4-point and 8-point connectivity in graph based planning?

In graph-based planning (say, A*), states are connected to their neighbors. How should one decide whether to connect to the 4 neighbors or the 8 neighbors? What are the pros and cons of each ...
10
votes
2answers
181 views

How to model the noise in a range sensor's return?

Range sensors (for example sonar, infrared, and lidar) are notoriously noisy. How can I characterize the noise characteristics to include these in a probabilistic localization sensor model?
23
votes
4answers
13k views

How should emergency stops be wired?

Emergency stops are obviously a good idea on most robots, how should they be wired? What systems should be killed immediately, and what should stay working?
29
votes
3answers
7k views

What is a suitable model for two-wheeled robots?

What is a suitable model for two-wheeled robots? That is, what equations of motion describe the dynamics of a two-wheeled robot. Model of varying fidelity are welcome. This includes non-linear models,...
9
votes
4answers
2k views

What connectors are most reliable?

If you have used connectors for signal wiring for any length of time, you may find that they are unreliable. Specifically, I find these to be unreliable when used for a long time, with a number of ...
5
votes
3answers
3k views

How to manage interrupts on an AVR?

I have a number of interrupt service routines on an AVR. These include interrupts for USART serial communication, timers, and SPI communication. For all of these, I use circular queues (using a start ...
-6
votes
2answers
136 views

Developing for 8-bit AVR-s, what are the current, open and free libraries out there? [closed]

I would be very interested to ask for a list of repos of free open code, applicable to 8-bit avr-s and having relation to robotics - object avoidance, process controllers, battery management, etc. ...
2
votes
1answer
221 views

What BLDC servo drive takes sinusoidal hall sensor signals?

I am looking for a servo drive to control a brushless DC motor, with at least 10A, 30V rating. However, I want to know if any exist which take sinusoidal hall sensor signals directly. I already know ...
12
votes
3answers
863 views

What determines the amount of noise an actuator produces?

Many robots and other mechanical devices produce the signature whirring noise as they move, some produce less. What makes the difference? What restrictions a silence requirement places on a robot?
4
votes
2answers
3k views

Mechanical design for motorized spherical caster wheels

Design goal is to have a mobile robot that operates on 3 large casters, essentially 2 to 4 inch diameter steel ball bearings, that are motorized. No other mechanism would touch the surface. The robot ...
8
votes
2answers
3k views

Shape Memory Alloy wire for robot gripper arm actuation: How to vary grip pressure?

For a robotic gripper arm we are designing for factory floor use on very small components, we propose to use electrically activated Shape Memory Alloy (SMA) wire harnesses for actuation. The device ...
7
votes
1answer
1k views

Using an Arduino to control an ON / OFF connection between two pins

I've got this driver: http://www.pololu.com/catalog/product/1182 ... a A4988 stepper motor driver carrier I'm attempting to control a connection between the RESET and SLEEP pins with logic ( code ) ...
12
votes
3answers
7k 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 ...
15
votes
4answers
316 views

Is it possible to both move and stabilize a two wheeled robot with no gyroscopes?

With two wheeled robot like this one, I have managed to stabilize it while keeping it stationary. This was done using a digital feedback control system by reading the position of the wheels to ...
13
votes
2answers
313 views

How can I detect if a DC motor on a robot is starting to fail?

What characteristics can I look for which could be reliable early warning signs that a DC motor on my robot, say one used for the drive, could be failing? I'm looking for an answer that deals in terms ...
8
votes
2answers
726 views

Adding external heat sinking to a Dynamixel RX-24F servo?

Hobby servos are generally not sufficient for real robotics for a number of reasons: Quality, precision, range of motion, torque, etc. Meanwhile, industrial servos, such as ABB, Emerson, GE, etc, are ...
9
votes
3answers
2k views

What algorithm can I use for constructing a map of an explored area using a number of ultrasound sensors?

Ultrasound sensors are incredibly cheap these days which makes them a popular choice for many hobbyist robotic applications, and I'd like to use a bunch of them (say 10) around a robot with an ...
12
votes
5answers
328 views

What's the most accurate way to obtain a locational fix using GPS?

Obviously GPS is the most obvious and accessible technology for obtaining a locational "fix" for a robot at any particular time. However, while it's great sometimes, in other locations and situations ...
11
votes
4answers
837 views

How can I best protect sensitive components against damage through vibration?

It's common for components on some types of robots to experience large environmental stresses, one key one being vibration. Is this something I need to worry about with typical electronics and other ...
18
votes
3answers
655 views

What's the most effective type of rechargeable battery when taking into account size / weight / Ah?

I'm looking to build an underwater glider robot that will need to remain autonomous for long periods of time, perhaps even months. Power draw should be minimal, and I'm thinking of including some form ...
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 ...
25
votes
3answers
3k views

What algorithm should I use for balancing a two wheeled robot using a gyroscope?

Is there a good, popular and reliable algorithm I can use by taking input from a gyroscope and using this to control two independant wheels to keep such a balanced robot reliably upright? I'm looking ...
10
votes
1answer
315 views

What tyre tread would be best suited to an off road robot expected to deal with frequently muddy conditions?

I'm looking to potentially build an autonomous robot that will frequently venture off road, and remain autonomous for up to 6 hours at a time. I've found limited information however about the best ...
5
votes
5answers
325 views

I'd like to use gesture based input for my robot. What are the pros and cons between the Xtion Live and the Kinect?

As in the title, I'd like to implement gesture recognition on my robot and I'm looking for the pros and cons between the Kinect and the Xtion - and also if there are any other sensible options ...
-3
votes
2answers
800 views

Mobile robot localization in a known map [closed]

I want to localize a mobile robot equipped with a 2D laser scanner in a known indoor environment. The map is a 2D occupancy grid, but is not perfect. What algorithms are appropriate for mobile robot ...
-12
votes
1answer
151 views

Cheap web to buy robotic pieces from [closed]

I love computer programming, and if I can interact with the world programming, it's even better. I used to steal them from school, and make little robots that bounce when collided with a wall, but I ...
40
votes
2answers
67k views

How to choose the right propeller/motor combination for a quadcopter?

There are many sites which explain briefly this problem and even propose combinations. I however would like a much more detailed explanation. What is going to give my quad the most agility? Do I need ...
5
votes
3answers
184 views

F/OSS Optical Object Avoidance

I am beginning work on a larger scale, 250-350 lbs wheeled robot and looking to use both optical and other means of object avoidance. I am concerned with a robot this large causing issues with running ...

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