# Tag Info

Accepted

### Holonomics Movement vs Holonomics Constraint

You can look at degrees of freedom as if they were the number of variables that you need to use to describe your system. So, for a robot moving in a 2D plane, its state would be represented by:  s=\...
• 224

### Do I need to use separate function in PID algorithm to make the bot go LEFT or RIGHT?

No, but you do need to calculate the P/I/D terms correctly. You have: I = I + previous_I; followed by: previous_I = I; ...
• 15.9k

### Is there any robot stability control equation that describes the relation between velocity of the robot and its orientation?

That's not obvious. If I'm in a tank, going 0.5 km/h, I don't need to slow down at all. If I'm in a bobsled going 100km/h and the track banks, I don't need to slow down at all. When you steer, you ...
• 15.9k

### How has the Mars Exploration Rover (MER) has been working for 11 years if it was designed for 90 Sol?

There are 2 main reasons why the MER is still operating long after it's 90 Sol planned lifetime. The first is political, strategic, and can be summarized as 'Under promise, over deliver'. When a PI (...
• 4,445
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### What is the difference between the pose of a robot and the configuration of a robot?

Do "configuration" and "pose" means the same thing? No. One of the most clear definitions of 'pose' that I've heard is in Peter Corke's Robotics, Vision and Control (RVC). It states that: "The ...
• 1,074

### How to control a 4 wheel mechanum wheel robot with PID?

Let's consider first the task you are wanting to accomplish: following some sort of Cartesian space trajectory. So, you are wanting to make sure your robot is only moving in the x-direction. However, ...
• 904
Accepted

### Handling PID DC motor control at low speeds

I came up with a solution in the end. Fire a periodic interrupt at a fixed rate (In my case, I configured the STM32 to fire a systick interrupt every 1ms In the ISR for the 1ms timer, decrement a ...
• 91

### 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 ...
• 71
Accepted

### Motion planning and robot controlling

The model you have given is called the unicycle model and is widely used n robotics. In general the model is given by \begin{eqnarray} \dot{x} &= v\cos \theta \\ \dot{y} &= v\sin \theta \\ \...
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 "...
• 15.9k

### Holonomics Movement vs Holonomics Constraint

A holonomic constraint applies to the configuration variables, it is represented by an equation is some or all of the configuration variables. A constraint that applies to the rate of change of the ...
• 1,712
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### How to increase the traction of tyres/wheels

Two seemingly contradictory approaches come to mind. One is to increase the friction between the wheels and the track. You can do this by coating the tires with a soft material, such as a gasket or ...
• 4,396
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### 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 ...
• 2,814

### Will there be any interference when distance sensors facing each other?

The amount of interference highly depends on the sensor type and how you use them. One of the worst for this is probably ultrasonic rangers: These are going out of fashion now, but older robots used ...
• 5,865

### what exactly is 'observation model' for a robot

An observation model is what relates your measurement to your states. For example, you might have a state that is vehicle speed, but the only thing you can measure is tire RPM. Tire RPM is not vehicle ...
• 15.9k

### How to deal with asynchronous samples in a kalman filter framework multi-sensor fusion?

The correct way of integrating multi-rate observations in a Kalman framework when the measurements are unavailable is to let the system evolve resorting merely to the prediction steps. Therefore, set ...
• 4,005
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### Robot positioning using IMU quaternion data?

The quaternion only contains information about the rotation of the vehicle. It will not contain information about the location of you vehicle on a 2-d plane. One method of converting quaternions to ...
• 1,853
Accepted

### Choosing motor to buy after calculations

Since you don't know what assumptions they had in mind when they estimated the motor was good for a robot of a specific weight, I would not trust that. You have established your own requirements and ...
• 4,445
Accepted

### Line-following robot with a 5th wheel

I m not familiar with those robots, but I will guess it's more used for odometry, in order to know the speed and the traveled distance. The design are packed so it is hard to see for sure, but it ...
• 1,411

### Line-following robot with a 5th wheel

The first robot is RS-100 and it won this year's all-Japan fine following competition. The fifth wheel is an encoder. The robots are allowed to remember the track - this is specific to this ...

### Balancing robot - How to control the velocity and angle

First of all, well done on getting your robot to balance! If you’ve got this far the rest should be easy. A cascading PI loop (no D) works very well for this. You have an outer loop to control the ...
• 21
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### How many encoders should I have?

Typically you will only need 2 encoders to estimate the velocity and the angle for a differential vehicle. If you are using more strategies than only the odometry for the localisation, you can ...
Accepted

### Interference caused by multiple robots during task completion

I came across one paper that had a good description of this issue from Kristina Lerman and Aram Galstyan at University of Southern California entitled "Mathematical Model of Foraging in a Group of ...
• 192

### Why my stepper motor doesn't move when I attach a blade?

I will take a wild guess - your accellerating to fast for the mass of the blade / power of the stepper motor. You can check this by trying to step much slower - perhaps 1 step per second for testing
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### Controllability of a car with a single trailer

"A car with n trailers" is known to be a differentially flat system. Flatness implies that the Lie algebra generated by the system's vector fields (f and g_i's) is full. Therefore, the example you ...
• 377

### Multiple robots performing a set of tasks (Optimization)

Try looking to Linear Integer Programming LIP where you are doing optimization by maximizing task allocation or Utility function at the same time minimizing distance and energy constraints. You will ...
Accepted

### What robotic skills can I develop when working as a robot operator?

Considering your apparent education background, I’m surprised at this question... But regardless. Working with robots, when compared to making robots are very different things. This is not so much ...
Accepted

### Are rotary encoders necessary for ball shooting mechanism?

Yes. Motors of the same type, by the same manufacturer, driven by the same voltage may still have different angular velocities (and different torque curves and any other parameter). There are a ...
• 5,865