JSycamore
  • Member for 6 years, 9 months
  • Last seen more than 2 years ago
How do monocular visual odometry algorithms work?
8 votes

Monocular vision is a difficult and very interesting, particularly in its application to the general navigation problem. I will make an attempt at answering your questions, but if you find anything ...

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Localising a robot placed at an unknown position in a known environment
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3 votes

The problem is that you can't apply path planning until you know where the robot is in the global coordinate frame. There are many localization techniques, and each has its pros/cons; I have used ...

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Linearize a non linear system
3 votes

The short answer to this question is that linearization won't work, and here's why: Differential drive robots can be modeled with unicycle dynamics of the form: $$\dot{z}=\left[\begin{matrix}\dot{x}\\...

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Stabilising an inverted pendulum
3 votes

The theory that describes what you are looking for is call Control Theory. Search for the Nonlinear Systems textbook by Hassan Khalil for an excellent overview of the material--the inverted pendulum ...

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Arduino-Create 2: Reading Sensor Values
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3 votes

As it turns out, I was not loading the sensor values into the array properly. It seems that data is transmitted one byte at a time, so the sensorbytes array needed to be an array of 4 elements rather ...

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Urdf as a way to model dynamics?
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2 votes

No. URDF is a convenient way to format information about the model; it is not a model itself.

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what books do you suggest for a beginner like me ?
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2 votes

If you only want a single comprehensive text on Robotics, I would recommend the Springer Handbook of Robotics. I covers everything from controls and artificial intelligence to perception and mechanics;...

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What does internal sparking in a motor mean?
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2 votes

If you are using a brushed DC motor, then (hopefully) the sparks that you are seeing are a discharge between the commuter and the brushes--this is normal. Another example of this is evident in certain ...

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Switch activated by a microcontroller
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2 votes

You can use a relay for the switch. Relays typically have 4 pins: 2 are the switch, and the other 2 control the switch. For reed relays, the switch is a small metal reed (normally closed) that makes ...

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What are the prerequisites for learning ROS?
2 votes

To learn and use ROS, you do not need to know anything about Linux kernel development, and at first, you shouldn't need to worry about writing drivers. All you need to know is how to use a command ...

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How do the PID parameters (Kp, Ki, and Kd) affect the heading of a differential driving robot when they are increased individually?
2 votes

Andy's response is good, and he hits all of the important points but to fully understand PID control in the context of a differential drive robot, it might be useful to take a step back and consider ...

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What are the biggest challenges to build an highly performant robotic hand?
2 votes

Replying to your comment and the robotic hand mentioned in Gizmag, I think I can answer some of your questions, but before I begin, there are some important references that you should consult to ...

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holonomic and non holonomic constraints in layman's term
1 votes

A constraint on the $k$ coordinates $r_1,r_2,...,r_k$ is holonomic if it is an equality constraint of the form $$g(r_1,...,r_k)=0,$$ and nonholonomic otherwise. These sorts of constraints arise ...

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Is there any error analysis of Irobot Create 2?
1 votes

Ostensibly, the error in angular and linear velocity of the Create 2 is quite large--this is due in part to limitations of open-loop control of the robot based on motor encoders that introduce ...

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I want to know whether the Create2 can interface a LIDAR?
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1 votes

If you are willing to work at it, adding LIDAR to the Create 2 should be possible. If you read the iRobot Create 2 OI Specs, you will see that you can communicate with the Create via serial ...

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Is it possible to detect road surface or navigation area using LRF data or other laser data in a Park?
1 votes

Is it possible to detect road surface (not grass) using LRF data or other laser sensors? Yes it is possible. A laser scanner will give distance measurements along a scan line. Presumably, the road ...

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What are the specifications of the digital compass used in iPhone 6S
1 votes

Typically, and unsurprisingly, proprietary information (to include part numbers, schematics, etc.) is closely guarded by companies. As such, I am not sure how much information you can expect to ...

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Find object using only distance
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1 votes

There are two challenges that you will have to address. First is localization of the robot relative to the Bluetooth source; second is the controller that will drive the robot to the source. To ...

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Using robotic simulator for prediction step in probabilistic localization approaches
1 votes

In the probabilistic approaches that you mentioned, specifically Monte Carlo Localization (MCL), the prediction step is made based on state (pose) information and measurements. MCL relies on the ...

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iRobot Create2: Granularity of drive control?
1 votes

In my brief stint working with the Create 2, I noticed the same thing. Specifying very low velocities doesn't work very well, and small increases don't seem to do anything up to a certain point. This ...

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Detect physical touch/hit
1 votes

One option could be to use the MPU6050 IMU, or some other accelerometer. These sensors are cheap, so they will come in under your budget. With acceleration measurements, you can detect impulses ...

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Arduino or Raspberry Pi?
1 votes

One point that hasn't been addressed, which is admittedly outside the scope of the prompt, is whether or not a Pi should be used at all as the off-board component. Unless you are trying to develop on ...

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What frequency does my quadcopter output-sense-calculate-output update loop need to stay stable?
1 votes

Your question can only be answered specifically if we have the model parameters of your system. The most principled approach to answering your question would be to represent the highly nonlinear ...

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How to create a model for temperature control?
1 votes

Chuck is right; you need to build a model so that you can appropriately choose your controller. Temperature control is non-trivial because the underlying dynamics are non-linear. Because heat ...

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Stability of PID values update function for quadrotor
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1 votes

I think I may have reason for your reviewer's caution. You are updating the proportional gain of a PID controller, and you are concerned with the stability of your update law. Restating your update: $$...

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Angular momentum of rimless wheel in Passive Dynamic Walking
1 votes

There are some fundamental problems with your questions. First, $\alpha_0$ and $r_{gyr}$ are fixed parameters that depend on the passive walker. Second, the equation $$H^-=I*\omega=(cos(2 \alpha_0)...

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Brushless motor from RC car won't spin with even small resistance
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1 votes

A couple of things to check: First, does the gear assembly work smoothly? If it doesn't, then the motor might have broken when attempting to work against too much resistance. Second, if you apply a ...

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Best sensor to determine "up" versus "down"
1 votes

I agree with holmeski's suggestion that an accelerometer is the way to go for static projects, but if you need more sophisticated measurements, an accelerometer/gyroscope combo will be necessary. The ...

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Is there a bug in the Encoder Counts packets 43&44?
1 votes

Jack, I have been working on determining the angle from the encoders. I recall running up against a similar problem to the one that you are facing. First off, unless you are spinning the wheels ...

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Issue with multiple bytes from Irobot Create 2
1 votes

Many of the sensors send data in 2 bytes and I need a way to make sure that it is combined automatically. Robb, I have been working on a project and have faced a similar problem. The best way that I ...

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