7 votes

Sphero's logic, how does it work

The principle lying underneath the sphero robot's design and locomotion is shifting of the centre of mass of the ball and making it unstable which makes the ball roll [1,3,4,5,6]. A controlled and ...
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  • 173
3 votes

Accounting for error in multiple electric motors

You're describing an encoder. It will give you a signal every time the wheel turns a some amount of degrees. http://www.bot-thoughts.com/2011/03/avc-bot-wheel-encoders.html
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  • 1,823
3 votes
Accepted

How to find kinematics of differential drive caster robot?

Kinematics of mobile robots For the figure on the left: I = Inertial frame; R = Robot frame; S = Steering frame; W = Wheel frame; $\beta$ = Steering angle; For the figure on the right: L = ...
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3 votes

Self balancing robot control system strategies

I can recommend an alternative which has worked for me quite well. I derived the dynamical model of a inverted pendulum, then linearised it around the stable operating point. With this simplified ...
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  • 71
3 votes
Accepted

State space model

Unfortunately, you're trying to apply a linear controller (the L of LQR) to a nonlinear system. In general, this doesn't work. As an approximation, you could linearize the system. If the ...
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  • 2,689
3 votes
Accepted

TWIP robot - DC gearmotor speed/Encoders

:EDIT: Let me put some numbers on this. Let's say you want to get from any angle to vertical in half a second. Say for now (more on this unrealistic scenario later) that you want to get from "...
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  • 14.9k
3 votes

Force calculations for a wheeled robot

I've calculated a max. traction force of 6.51N. Does this mean a torque force at the wheels of up to and including 6.51N can be applied, to drive the robot without the wheels slipping? ... ...
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  • 4,395
2 votes
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Determining rated speed (RPM) required for a DC gearmotor

Yes, that's correct. A "good choice" for acceleration has nothing to do with velocity. Generally, acceleration limits are chosen based on motor thermal ratings. You should have some design load the ...
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  • 14.9k
1 vote

How to design a robot chassis so as to avoid bending issues?

It is difficult to provide a specific answer due to not knowing details of your design, but consider these factors for the deflection of a beam. They should give you ideas. For a beam supported at ...
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  • 4,336
1 vote

I2C Arduino Connection

The code you provide is only to give you example on how 2 arduino communicate using I2C protocol. You will need to modify it so it can fully work as intended. You can modify it so Arduino Mega can ...
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1 vote

Can Swedish wheels be used in two wheeler configuration?

This started out as a comment but I ran out of space. Also, I am waiting for the question to be clarified, as morbo has requested of the OP. Here is an example on YouTube, Lego Technic two-wheeled ...
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  • 1,284
1 vote

Connect 2 motor controllers

You should use the individual wheel velocities at all times to compute the robot's heading and angular and linear velocity and super-impose another controller that works to correct the same. This ...
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1 vote

Connect 2 motor controllers

If going completely straight is the goal then you'll need more feedback than just the wheel speeds. Even if you could guarantee the wheels turned at exact same speed (say for instance they were ...
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1 vote

How do I compute the translation and rotation velocities of a robot

As Chuck said you are using the parametric form of the ellipse $p(t) = (m) + cos(t)*a + sin(t)*b$ the $t$ doesn't represent the time but the eccentric anomaly. But from this equation you can create ...
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  • 191
1 vote

How to implement a particle filter when sensors can't identify landmarks?

SLAM is only needed when you are also building a map. You already have a map so the problem is localization. To be exact the problem you want to research is Monte Carlo localization or particle filter ...
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  • 1,581
1 vote

Wheel encoder triggers interrupt too many times

Your signal actual going back and forth like that; it's registering with the microcontroller because you're at an intermediate voltage. As @TobiasK mentions, this is called "bouncing". You're trying ...
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  • 14.9k
1 vote

How to find kinematics of differential drive caster robot?

Well, if it is truly a caster wheel with two differential drives, then I'd just assume that the castor is not a constraint at all! It's a freely rotating wheel that should just follow the direction ...
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1 vote

High-traction thin tires vs Wide moderate-traction tires? [Sumo-bot]

Well, I moved my answer here from the Engineering SE because it looks like your question is probably going to get closed there, just like it got closed at the physics site. Assuming everything about ...
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  • 14.9k
1 vote
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Accounting for error in multiple electric motors

"Is there a way to account for possible error in the speeds of the motors so that the robot can end up in a very precise location?" The other answers describe the approximate solution (encoders). It ...
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  • 2,013

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