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BRobot Oscillation then fall over
06-22-2017, 04:58 PM (This post was last modified: 06-22-2017 05:00 PM by Bondo.)
Post: #1
BRobot Oscillation then fall over
Completed my B Robot yesterday, but it is having trouble staying upright. Although not a kit, I bought the stepper motors, brain shield and stepper drivers from JJRobots, and it is built according to the instructions on the site. It is almost identical to the kit, using the same hardware although I do not have a servo fitted yet. However ... it refuses to stay upright. It goes through the calibration stage and all seems well. But then when I try to stand it up, the robot oscillates forwards and backwards. It will stay upright for a short time (occasionally) but any attempt to move it either by pushing gently or using the wifi app will result in it rocking wildly then falling over.

I have been through all the relevant threads on this forum, and tried moving the gyro to the top of the bot, but this made no difference. Also ran through some of the debug code, and there was one error, but I don't know what it means. Here is some of the pertinent output:


OK
MAC:5CCF7FACE0BD

AT+CWQAP

QAP fail

ERROR
!Timeout!
AT+CWMODE=2


Does anyone know what this error means and why it was generated?

I have posted a video of this erratic behaviour:

https://youtu.be/lgKP8SFiRL8

Perhaps I need to make some adjustments to the parameters in the code? Or is the hardware causing this error? I really don't know, so would appreciate some guidance from the more experienced members of the forum.
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06-22-2017, 07:03 PM
Post: #2
RE: BRobot Oscillation then fall over
(06-22-2017 04:58 PM)Bondo Wrote:  Completed my B Robot yesterday, but it is having trouble staying upright. Although not a kit, I bought the stepper motors, brain shield and stepper drivers from JJRobots, and it is built according to the instructions on the site. It is almost identical to the kit, using the same hardware although I do not have a servo fitted yet. However ... it refuses to stay upright. It goes through the calibration stage and all seems well. But then when I try to stand it up, the robot oscillates forwards and backwards. It will stay upright for a short time (occasionally) but any attempt to move it either by pushing gently or using the wifi app will result in it rocking wildly then falling over.

I have been through all the relevant threads on this forum, and tried moving the gyro to the top of the bot, but this made no difference. Also ran through some of the debug code, and there was one error, but I don't know what it means. Here is some of the pertinent output:


OK
MAC:5CCF7FACE0BD

AT+CWQAP

QAP fail

ERROR
!Timeout!
AT+CWMODE=2


Does anyone know what this error means and why it was generated?

I have posted a video of this erratic behaviour:

https://youtu.be/lgKP8SFiRL8

Perhaps I need to make some adjustments to the parameters in the code? Or is the hardware causing this error? I really don't know, so would appreciate some guidance from the more experienced members of the forum.
Hi, to help, we need some photos of your assembly, front and back ; sure the connections from MPU board was too long. The signals from this board are critical to obtain best results. Where do you place this board before and how ? During the initialization phase, the steppers vibrate slightly? What software has been used?
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06-22-2017, 09:57 PM
Post: #3
RE: BRobot Oscillation then fall over
(06-22-2017 07:03 PM)Carlo1951 Wrote:  
(06-22-2017 04:58 PM)Bondo Wrote:  Completed my B Robot yesterday, but it is having trouble staying upright. Although not a kit, I bought the stepper motors, brain shield and stepper drivers from JJRobots, and it is built according to the instructions on the site. It is almost identical to the kit, using the same hardware although I do not have a servo fitted yet. However ... it refuses to stay upright. It goes through the calibration stage and all seems well. But then when I try to stand it up, the robot oscillates forwards and backwards. It will stay upright for a short time (occasionally) but any attempt to move it either by pushing gently or using the wifi app will result in it rocking wildly then falling over.

I have been through all the relevant threads on this forum, and tried moving the gyro to the top of the bot, but this made no difference. Also ran through some of the debug code, and there was one error, but I don't know what it means. Here is some of the pertinent output:


OK
MAC:5CCF7FACE0BD

AT+CWQAP

QAP fail

ERROR
!Timeout!
AT+CWMODE=2


Does anyone know what this error means and why it was generated?

I have posted a video of this erratic behaviour:

https://youtu.be/lgKP8SFiRL8

Perhaps I need to make some adjustments to the parameters in the code? Or is the hardware causing this error? I really don't know, so would appreciate some guidance from the more experienced members of the forum.
Hi, to help, we need some photos of your assembly, front and back ; sure the connections from MPU board was too long. The signals from this board are critical to obtain best results. Where do you place this board before and how ? During the initialization phase, the steppers vibrate slightly? What software has been used?

The code I used is the following:

// B-ROBOT SELF BALANCE ARDUINO ROBOT WITH STEPPER MOTORS
// JJROBOTS BROBOT KIT: (Arduino Leonardo + BROBOT ELECTRONIC BRAIN v2 + STEPPER MOTOR drivers)
// This code is prepared for new BROBOT shield v2.0 with ESP8266 Wifi module
// You need to install libraries JJROBOTS_OSC, JJROBOTS_BROBOT, I2Cdev and MPU6050 (from Github repository)
// Author: JJROBOTS.COM (Jose Julio & Juan Pedro)
// Date: 02/09/2014
// Updated: 26/10/2015
// Version: 2.21
// License: GPL v2

I think this is the most up to date code. Pictures of the assembly are attached. As I said, I followed the kit instructions as far as possible. Originally, I placed the IMU module on top of the brain shield as instructed, but the robot was unstable and oscillated. I then tried placing it on the top shelf as suggested in one of the threads, but it made no difference.

Here are a few images:

[Image: DSCN0513.jpg]
[Image: DSCN0515.jpg]
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06-23-2017, 09:32 AM
Post: #4
RE: BRobot Oscillation then fall over
(06-22-2017 09:57 PM)Bondo Wrote:  
(06-22-2017 07:03 PM)Carlo1951 Wrote:  
(06-22-2017 04:58 PM)Bondo Wrote:  Completed my B Robot yesterday, but it is having trouble staying upright. Although not a kit, I bought the stepper motors, brain shield and stepper drivers from JJRobots, and it is built according to the instructions on the site. It is almost identical to the kit, using the same hardware although I do not have a servo fitted yet. However ... it refuses to stay upright. It goes through the calibration stage and all seems well. But then when I try to stand it up, the robot oscillates forwards and backwards. It will stay upright for a short time (occasionally) but any attempt to move it either by pushing gently or using the wifi app will result in it rocking wildly then falling over.

I have been through all the relevant threads on this forum, and tried moving the gyro to the top of the bot, but this made no difference. Also ran through some of the debug code, and there was one error, but I don't know what it means. Here is some of the pertinent output:


OK
MAC:5CCF7FACE0BD

AT+CWQAP

QAP fail

ERROR
!Timeout!
AT+CWMODE=2


Does anyone know what this error means and why it was generated?

I have posted a video of this erratic behaviour:

https://youtu.be/lgKP8SFiRL8

Perhaps I need to make some adjustments to the parameters in the code? Or is the hardware causing this error? I really don't know, so would appreciate some guidance from the more experienced members of the forum.
Hi, to help, we need some photos of your assembly, front and back ; sure the connections from MPU board was too long. The signals from this board are critical to obtain best results. Where do you place this board before and how ? During the initialization phase, the steppers vibrate slightly? What software has been used?

The code I used is the following:

// B-ROBOT SELF BALANCE ARDUINO ROBOT WITH STEPPER MOTORS
// JJROBOTS BROBOT KIT: (Arduino Leonardo + BROBOT ELECTRONIC BRAIN v2 + STEPPER MOTOR drivers)
// This code is prepared for new BROBOT shield v2.0 with ESP8266 Wifi module
// You need to install libraries JJROBOTS_OSC, JJROBOTS_BROBOT, I2Cdev and MPU6050 (from Github repository)
// Author: JJROBOTS.COM (Jose Julio & Juan Pedro)
// Date: 02/09/2014
// Updated: 26/10/2015
// Version: 2.21
// License: GPL v2

I think this is the most up to date code. Pictures of the assembly are attached. As I said, I followed the kit instructions as far as possible. Originally, I placed the IMU module on top of the brain shield as instructed, but the robot was unstable and oscillated. I then tried placing it on the top shelf as suggested in one of the threads, but it made no difference.

Here are a few images:

[Image: DSCN0513.jpg]
[Image: DSCN0515.jpg]
The software is the first version. Apparently everything looks good. With my first robot equal to yours I had similar problems that I then solved. I have noticed that the main problem is the IMU circuit, which must have very short connections, must be fixed in a STABLE position and oriented as much as possible along the axis of the robot. In addition, the steppers generate many noise, which could affect the same IMU, then attempt to shield these connections.
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06-23-2017, 11:16 AM
Post: #5
RE: BRobot Oscillation then fall over
(06-23-2017 09:32 AM)Carlo1951 Wrote:  
(06-22-2017 09:57 PM)Bondo Wrote:  
(06-22-2017 07:03 PM)Carlo1951 Wrote:  
(06-22-2017 04:58 PM)Bondo Wrote:  Completed my B Robot yesterday, but it is having trouble staying upright. Although not a kit, I bought the stepper motors, brain shield and stepper drivers from JJRobots, and it is built according to the instructions on the site. It is almost identical to the kit, using the same hardware although I do not have a servo fitted yet. However ... it refuses to stay upright. It goes through the calibration stage and all seems well. But then when I try to stand it up, the robot oscillates forwards and backwards. It will stay upright for a short time (occasionally) but any attempt to move it either by pushing gently or using the wifi app will result in it rocking wildly then falling over.

I have been through all the relevant threads on this forum, and tried moving the gyro to the top of the bot, but this made no difference. Also ran through some of the debug code, and there was one error, but I don't know what it means. Here is some of the pertinent output:


OK
MAC:5CCF7FACE0BD

AT+CWQAP

QAP fail

ERROR
!Timeout!
AT+CWMODE=2


Does anyone know what this error means and why it was generated?

I have posted a video of this erratic behaviour:

https://youtu.be/lgKP8SFiRL8

Perhaps I need to make some adjustments to the parameters in the code? Or is the hardware causing this error? I really don't know, so would appreciate some guidance from the more experienced members of the forum.
Hi, to help, we need some photos of your assembly, front and back ; sure the connections from MPU board was too long. The signals from this board are critical to obtain best results. Where do you place this board before and how ? During the initialization phase, the steppers vibrate slightly? What software has been used?

The code I used is the following:

// B-ROBOT SELF BALANCE ARDUINO ROBOT WITH STEPPER MOTORS
// JJROBOTS BROBOT KIT: (Arduino Leonardo + BROBOT ELECTRONIC BRAIN v2 + STEPPER MOTOR drivers)
// This code is prepared for new BROBOT shield v2.0 with ESP8266 Wifi module
// You need to install libraries JJROBOTS_OSC, JJROBOTS_BROBOT, I2Cdev and MPU6050 (from Github repository)
// Author: JJROBOTS.COM (Jose Julio & Juan Pedro)
// Date: 02/09/2014
// Updated: 26/10/2015
// Version: 2.21
// License: GPL v2

I think this is the most up to date code. Pictures of the assembly are attached. As I said, I followed the kit instructions as far as possible. Originally, I placed the IMU module on top of the brain shield as instructed, but the robot was unstable and oscillated. I then tried placing it on the top shelf as suggested in one of the threads, but it made no difference.

Here are a few images:

[Image: DSCN0513.jpg]
[Image: DSCN0515.jpg]
The software is the first version. Apparently everything looks good. With my first robot equal to yours I had similar problems that I then solved. I have noticed that the main problem is the IMU circuit, which must have very short connections, must be fixed in a STABLE position and oriented as much as possible along the axis of the robot. In addition, the steppers generate many noise, which could affect the same IMU, then attempt to shield these connections.

Am I using the wrong version of the software? The one I downloaded was the one that was cited on the JJRobots website, so I assumed it to be the most recent. If there is a more up to date version, can you point me to where it is located. Thanks.
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06-23-2017, 12:14 PM
Post: #6
RE: BRobot Oscillation then fall over
(06-23-2017 11:16 AM)Bondo Wrote:  
(06-23-2017 09:32 AM)Carlo1951 Wrote:  
(06-22-2017 09:57 PM)Bondo Wrote:  
(06-22-2017 07:03 PM)Carlo1951 Wrote:  
(06-22-2017 04:58 PM)Bondo Wrote:  Completed my B Robot yesterday, but it is having trouble staying upright. Although not a kit, I bought the stepper motors, brain shield and stepper drivers from JJRobots, and it is built according to the instructions on the site. It is almost identical to the kit, using the same hardware although I do not have a servo fitted yet. However ... it refuses to stay upright. It goes through the calibration stage and all seems well. But then when I try to stand it up, the robot oscillates forwards and backwards. It will stay upright for a short time (occasionally) but any attempt to move it either by pushing gently or using the wifi app will result in it rocking wildly then falling over.

I have been through all the relevant threads on this forum, and tried moving the gyro to the top of the bot, but this made no difference. Also ran through some of the debug code, and there was one error, but I don't know what it means. Here is some of the pertinent output:


OK
MAC:5CCF7FACE0BD

AT+CWQAP

QAP fail

ERROR
!Timeout!
AT+CWMODE=2


Does anyone know what this error means and why it was generated?

I have posted a video of this erratic behaviour:

https://youtu.be/lgKP8SFiRL8

Perhaps I need to make some adjustments to the parameters in the code? Or is the hardware causing this error? I really don't know, so would appreciate some guidance from the more experienced members of the forum.
Hi, to help, we need some photos of your assembly, front and back ; sure the connections from MPU board was too long. The signals from this board are critical to obtain best results. Where do you place this board before and how ? During the initialization phase, the steppers vibrate slightly? What software has been used?

The code I used is the following:

// B-ROBOT SELF BALANCE ARDUINO ROBOT WITH STEPPER MOTORS
// JJROBOTS BROBOT KIT: (Arduino Leonardo + BROBOT ELECTRONIC BRAIN v2 + STEPPER MOTOR drivers)
// This code is prepared for new BROBOT shield v2.0 with ESP8266 Wifi module
// You need to install libraries JJROBOTS_OSC, JJROBOTS_BROBOT, I2Cdev and MPU6050 (from Github repository)
// Author: JJROBOTS.COM (Jose Julio & Juan Pedro)
// Date: 02/09/2014
// Updated: 26/10/2015
// Version: 2.21
// License: GPL v2

I think this is the most up to date code. Pictures of the assembly are attached. As I said, I followed the kit instructions as far as possible. Originally, I placed the IMU module on top of the brain shield as instructed, but the robot was unstable and oscillated. I then tried placing it on the top shelf as suggested in one of the threads, but it made no difference.

Here are a few images:

[Image: DSCN0513.jpg]
[Image: DSCN0515.jpg]
The software is the first version. Apparently everything looks good. With my first robot equal to yours I had similar problems that I then solved. I have noticed that the main problem is the IMU circuit, which must have very short connections, must be fixed in a STABLE position and oriented as much as possible along the axis of the robot. In addition, the steppers generate many noise, which could affect the same IMU, then attempt to shield these connections.

Am I using the wrong version of the software? The one I downloaded was the one that was cited on the JJRobots website, so I assumed it to be the most recent. If there is a more up to date version, can you point me to where it is located. Thanks.
No, the software it's right, is only the first version, i also use without problem. But there is a new one on : https://github.com/jjrobots/B-ROBOT_EVO2 , which is totally compatible with your hardware. But beware, the problem of the instability does not depend on the software used.
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06-23-2017, 12:27 PM
Post: #7
RE: BRobot Oscillation then fall over
That IMU placement looks like a little bit... strange. Can you try to place it closer to the motor and in the middle of the robot? (rotational axis) I am pretty sure the IMU is not providing good data placed on one side of the robot.
And another tip: the i2c cable used is too long. It is very sensitive to noise. I would reduce its length

Keep us udpdated!
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06-23-2017, 03:52 PM (This post was last modified: 06-23-2017 04:26 PM by Bondo.)
Post: #8
RE: BRobot Oscillation then fall over
(06-23-2017 12:27 PM)JohnQ Wrote:  That IMU placement looks like a little bit... strange. Can you try to place it closer to the motor and in the middle of the robot? (rotational axis) I am pretty sure the IMU is not providing good data placed on one side of the robot.
And another tip: the i2c cable used is too long. It is very sensitive to noise. I would reduce its length

Keep us udpdated!

I have done all of this. I have used a short cable as per the instructions on the website, placing the IMU on top of the Brain shield in the centre of the robot, but it makes absolutely no difference to the behaviour. I have tried shielded cable. No difference. I cannot make the i2c cable any shorter otherwise it would not reach the IMU. There must be something else causing this.

I noted that the stepper motor driver heat sinks are very poorly matched to the chips. If they are not placed exactly onto the top of the chip, they can short out the components on the board. Just thought I'd mention that.
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06-23-2017, 05:10 PM
Post: #9
RE: BRobot Oscillation then fall over
Attach a video of the robot oscillating. That will help to narrow the problem down.
What kind of batteries are you using?

PS: the heat-sinks are almost useless in this case. Just be careful they are not touching any pin
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06-23-2017, 07:58 PM (This post was last modified: 06-23-2017 07:59 PM by Bondo.)
Post: #10
RE: BRobot Oscillation then fall over
(06-23-2017 05:10 PM)jpedroc Wrote:  Attach a video of the robot oscillating. That will help to narrow the problem down.
What kind of batteries are you using?

PS: the heat-sinks are almost useless in this case. Just be careful they are not touching any pin

There is a link to the video above, where you can see it oscillating. here it is again:

Robot oscillating

I am using 8 AA batteries as per the original design of the robot.
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