# Questions tagged [imu]

Inertial Measurement Unit

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### Filtering IMU angle discontinuities

I try to measure Euler angles from an IMU, but some discontinuities happens during measurement, even in vibrationless environment, as shown in the images below. Can someone explain which type of ...
• 107
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### Gyro measurement to absolute angles

Let us assume we have a gyro that is perfectly aligned to a global frame ($X,Y,Z$). From what I know the gyro data give me the angular rate with respect to the gyro axis ($x,y,z$). So let's say I ...
• 341
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### Angular velocities and rotation matrices

Let us assume I have an object O with axis $x_{O}$, $y_{O}$, $z_{O}$, with different orientation from the global frame S with $x_{S}$, $y_{S}$, $z_{S}$ (I don't care about the position). Now I know ...
• 341
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### Aligning datasets with drift

I have a dataset that contains position information from tracking a robot in the environment. The position data comes both from a very accurate optical tracking system (Vicon or similar) and an IMU. I ...
1 vote
605 views

### Balancing a plate with an IMU offset from the center

I recently bought a IMU . I am new at this. My question: Does the positioning of the IMU matter? Are there any differences between placing it at the center of the plate or if it is offset from the ...
• 311
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### Mobile Robot path reconstruction by using IMU acceleration and Yaw angle

I hope you can help me with my project. I'm using a skid-steering wheeled mobile robot for autonomous navigation and I'd like to find a way to be able to perform path reconstruction in Matlab. By ...
949 views

### Axis of rotation via IMU

Using an IMU (gyro, accelerometer and magnetometer), as found in most smartphones, can I detect the differences between tilting the device, say forward, along different (parallel) axis positions? To ...
• 193
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### Positioning Sensor

I would like to locate the position of a stationary autonomous robot in x-y-z axis relative to a fixed starting point. Could someone suggest sensors that would be suitable for this application? I am ...
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### Simple Sensor Fusion for pose estimation

I am currently working on a balancing robot project, which features fairly low-cost sensors such as an 9-Dof IMU with the measurement states \$\textbf{x}_\text{IMU} = \left[a_x, a_y, a_z, g_x, g_y, ...
• 278
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### Displacement with accelerometer [duplicate]

I want to use a sensor to find displacement with accelerometer. How can I use accelerometer to find displacement? I want to use this for a quadcopter.
2k views

### How do I choose the best filter for dead reckoning with an IMU?

I'm searching filter to reduce noise and smooth the signal while dead reckoning with an IMU (6dof gyro+accelerometer). What are the differences/advantages/disadvantages of the following filters: ...
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### IMU rotate about one axis, other two angles change too

I am trying to use Invensense's MPU9250. I am using provided library to read euler angle. When the IMU rotates about one axis, angles about other two axes change too. What could be potential cause to ...
• 491
1 vote
1k views

I recently decided to build a quadricopter from scratch using Arduino and now I'm faced with an orientation estimation problem. I bought a cheap 10DOF sensor with 3 axis magnetometer, 3 axis ...
564 views

### Problems about Complementary Filter IMU tuning

I'm developing a project consists of an IMU controlled by Arduino through which you can send via a radio module, the data to the PC of the three Euler angles and raw data from the sensors. For ...
799 views

### How to use an IMU to hover at a fixed location in a quadcopter in the presence of gravity?

There's an accelerometer in the IMU. The output can then be integrated to estimate the position, at least in theory. But in practice, there's a huge acceleration from gravity, which varies rather ...
• 101
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### Simulate IMU (2D gyro and accelerometer) data

If I have a robot path in 2D space, i.e. a vector of (x,y) locations, and I need to generate artificial IMU data (simulate them), how would I go about it? How do I model equations to generate the ...
• 195
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### Provides a 10 Degree-Of-Freedom IMU reduntant data?

Basic question concerning sensor fusion: A standard 10 DoF IMU, I mean this cheap things for the tinkerer at home, provides 10 values: 3 Accelerometers 3 Gyroscope 3 Magnetic Field Measurements 1 ...
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### How can I filter Gyroscopic data?

I am using an Arduino Mega with an MPU6050. I can get gyroscopic data as well as euler angles. The problem is my gyro data keeps going back and forth between 0 and -1 despite me not moving it at all (...
• 397
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### How do I get MPU 6050 gyroscope data using "MPU6050_6Axis_MotionApps20.h" library

I'm currently calibrating the MPU6050 chip using an arduino mega 2560. I am using the J Rowberg 12c dev libraries. I can get it to print raw accelerometer and gyroscpe values (very unstable, wildly ...
• 397
510 views

### Minimising lateral drift in a PID (Arduino) controlled quadcopter using a 6DOF IMU

I'm developing a stabilisation system for an 'off-the-shelf' quadcopter by using an Arduino Mega and an IMU. The IMU is reading the angle of the quad, calculating motor commands by using a PID ...
10k views

### How to track robot position?

I'm a software researcher, who in my spare time mentors a robotics team, helping on the software side of things. For years, I keep coming back to the same question: How to determine the robots ...
192 views

### FreeIMU External Magnetometer

I have been using the FreeIMU library successfully but now I want to add an external magnetometer that I can mount away from my motors. I've figured out how to modify the FreeIMU library to use an ...
2k views

### PID control of tank-like robot and IMU

Consider a tank like robot with a motor driver channel for each side of the robot (two motors on the left and two motors on the right) and an IMU. I'm interested in driving the robot in a straight ...
1 vote
537 views

### Fusion of GNSS position data and prefused 9-dof AHRS data

Bosch, FreeScale, InvenSense, ST and maybe others are releasing 9-dof AHRS platforms containing their own fusion software and outputting filtered/sane/fused data (attitude as quaternion and linear ...
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### 3-axis Magnetometer Question

Apologies if this is a stupid question, but if I have a 3-axis magnetometer, and I calculate the vector magnitude as sqrt(magX * magX + magY * magY + magZ * magZ) ...
• 597
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### differential robot yaw estimation using kalman filter

Hello i am building a differential drive robot which is equipped with quadrature encoders on both of the motors. My aim is to be able to predict the heading (yaw angle) of the robot using a kalman ...
182 views

### interfacing arduino uno with 9 dof razor imu

I have followed the tutorial for razor IMU and it worked perfectly when the IMU is directly connected to the PC. Currently, i am trying to interface the 9 dof razor imu with the arduino uno by simply ...
46k views

### How to estimate yaw angle from tri-axis accelerometer and gyroscope

I would like to estimate the yaw angle from accelerometer and gyroscope data. For roll and pitch estimate I've used the following trigonometric equations: ...
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### Is increasing gyro , accelerometer sensor range is good or bad ? how does it affect the accuracy

I've been using mpu6050 IMU unit ( gyro + accelerometer ) I found that I can set acc range to +/- 2g or 4g till 16 g and same for gyro +/- 250 deg/sec , 500 deg/sec and so I know that they are ...
• 169
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### Euler Angles from 9DOF IMU

Using the Adafruit 9DoF module I Need to convert the Accel + Magneto + Gyro into Euler Angles for a motion capture application. Any hints on where to start? Managed to get X,Y,Z when the IMU is ...
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1 vote
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### How to calibrate an IMU unit?

Simply , how can I calibrate IMU unit ? I read some papers about this topic and was wondering if there are any standard methods.
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### How to calculate Altitude from IMU?

How to calculate attitude from IMU ? For example, mathematical equations
• 137
1 vote
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### What's the difference between Yaw and Attitude in Quad Rotor

I have a big miss conception between Yaw and attitude ? Isn't both represent "how far is the quad from earth ?" Also if you could post how to calculate them from IMU (gyro +accele + magent )
• 137
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### IMU based acceleration parameters for differential drive robot

I have a differential drive robot whose motors are virtually quiet while driving on a completely flat surface, but the motors make a lot of noise when on a incline. This is likely due to the ...
• 203
1 vote
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I have built a quad copter completely from scratch (electronics, mechanics and software). I am now at the point where all my sensor data looks correct and when I tilt the quad copter the correct ...
510 views

### Simon K firmware when the IMU outputs at 50HZ

I am building a Quadcopter using the Sparkfun Razor IMU which outputs the Roll, Pitch and Yaw axes values at 50 Hz, which limits the operations of the controller(implemented on Arduino IMU), to 50 Hz ...
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### Accelerometer, gyro, and magnetometer sensor fusion in 2d

I have not yet built this so this is basically a theoretical question. I am still wrestling with some C code to manage i2c ...
77 views

### How to use TOA (Time Of Arrival) to measure 3-axis location of a wireless device? [closed]

I need to read the location of my device within a 1m radius sphere, with accuracy of 5-10cm. The device is handheld and wireless, and currently communicates using a Bluetooth v4 chip. I could add an ...
1k views

### How to measure displacement, cheaply and without using an accelerometer?

Motion is known to be confined in a sphere with radius of about 0.5m, and resolution doesn't have to be very high (5cm is enough). The device will actually be incorporated in a toy designed for kids. ...
1 vote
349 views

### Arduino for simple Data-Glove. Should I go with Mega or Due?

First, I'm a beginner in MCU/Robotic world (been working with ATMega+CVavr, but that's all). so please bear with me. I'm making a prototype data glove (Like KeyGlove, but much more simpler), it ...
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### Razor IMU Arduino interfacing

I was looking into the Razor IMU from Sparkfun, and realized that the only example code on sparkfun's website was for it was meant for hooking it up to a computer (the AHRS head tracker used a serial ...
• 420
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### Why do 3-axis accelerometers seemingly have a left-handed coordinate system?

Careful inspection of page 35 (figure 58) of the ADXL345 datasheet shows that under gravitational loading only, the chip uses a left-handed coordinate system. My own experiments with this chip ...
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### Tracking with accelerometer and gyro versus multiple accelerometers

I'm building quadcopter and most of the control systems use one accelerometer and gyro. I've read few papers and usually accelerometer is used as reference to the ground because gyro slowly drifts ...
• 131
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### How are units of noise measurement related to units of a sensor's data measurement?

I'm trying to understand how noise is represented for accelerometers, gyroscopes, and magnetometers so that I can match the requirements of my project with the standard specs of these sensors. I ...
• 2,122
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### Is there a benefit to using 2 IMU units on a UAV set at different sensitivities?

I noticed that some IMU units are tuned to be sensitive to small changes, other to large changes and some that can be adjusted between different sensitivities. I am familiar with the use of a Kalman ...
• 133
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We are using ArduIMU (V3) as our Quadrotor's inertial measurement unit. (we have a separate board to control all motors, not with ArduIMU itself). As mentioned here , the output rate of this module ...
315 views

### At which stage should filtering be applied to the sensors data?

Shall I filter (kalman/lowpass) after getting the raw values from a sensor or after converting the raw values to a usable data? Does it matter? If so, why? Example: Filter after getting raw values ...
563 views

### Chaining Kalman filters

My team is building a robot to navigate autonomously in an outdoor environment. We recently got a new integrated IMU/GPS sensor which apparently does some extended Kalman filtering on-chip. It gives ...
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