Preparations for GyroBot

Hi Martin,
I’m interested in writing GyroBoy program too. Now I’m only waiting for my wifi dongle.
I have read your post, and I think there are simplest approaches to do this program.
Maybe I’m wrong, but you are trying to think like in real-time os, but this is linux it is not real time.
You can’t specify timers and expect results in desired time. My approach is to think that is lego toy
not high precision robot. Program needs some simplifications, thread prioritization and other advanced thread managment functions are not needed.
Oryginal program is not ideal, I have found some bugs and glitches.

I don’t analyze all the tricky gyro stuff from oryginal program yet, but i have some initial
plan for my program:
– tasks with infinite loops for sensor sampling. Idle time (sleep) will determine sample rate.
– main thread with task handling loop
– priority queue for message handling.

I think I accomplish project in two weeks, then will share results/program with monobrick community.
PS
Sorry for my poor english.

Jacek

• This reply was modified 10 years, 11 months ago by Jacek S.

Hi,
I did some initial test of my gyro boy.
And I encountered some problems.
First and least important is gyro sensor only works in port1.
Second is that I don’t know how to use motor methods to simulate “unregulated motor” block.
SetPower do not start motor, and I was using sequence motor.On(0) and motor.SetPower(power).
I’m not sure is equivalent. After that the motor start rotating, but when i set it to off and quit program,
then start program again motors starting after new Motor(…) constructor,
before i set them to on. I don’t know how to avoid this.
The next thing is that the gyro sensor doesn’t have “rate and angle” mode
I have read that swithching to this mode is used to remove drift effect.
Last thing. Please confirm getTacho from motor is angle in degrees.

Jacek

Hi Anders,
I mean labview block. I’m trying to translate block sequence from original program to c# code.
I spend many hours during weekend but still with no success. Robot is far from balancing.
Still don’t know where is diffrence. Two points where I’m not sure is gyro sensor rate read and “unregulated motor”.
“Unregulated motor” in my program is sequence: motor.On() (if power < 0) motor.Reverse and motor.SetPower(power).
The oryginal program is very tricky and depends strongly on enviroment and even on battery level.

Fragment of my program(balance method):

        private void Balance()
        {

            var lastSumMotor = sumMotor;
            sumMotor = leftMotor.GetTachoCount() + rightMotor.GetTachoCount();

            var diffMotor = (sumMotor - lastSumMotor);
            rateMotor = 0.75 * rateMotor + 0.25 * (diffMotor / avgLoopTimer);
            angleMotor = moveMotor * avgLoopTimer + angleMotor + diffMotor;

            var gyroRead = (double)gyro.Read();
            rateGyro = gyroRead - offsetGyro;
            offsetGyro = 0.001 * gyroRead + 0.999 * offsetGyro;
            angleGyro = angleGyro + avgLoopTimer * rateGyro;

            motorPower = rateGyro * GYRO_RATE + angleGyro * GYRO_ANGLE + rateMotor * MOTOR_RATE
                + angleMotor * MOTOR_POS;

            if (motorPower < 0)
            {
                motorPower *= -1d;
                if (!leftMotor.Reverse) rightMotor.Reverse = leftMotor.Reverse = true;
            }
            else
            {
                if (leftMotor.Reverse) rightMotor.Reverse = leftMotor.Reverse = false;
            }

            if (motorPower > 100d) motorPower = 100d;

            leftMotor.SetPower((byte)motorPower);
            rightMotor.SetPower((byte)motorPower);
        }

Jacek

Hi Anders,
In all code examples I found setpower equivalent is used(in lejos segway.java and hitec nxc example, and labview ev3 program) I dont know why.

In lejos source code i found that power param for setpower is byte(in java is signed type) I changed this in monobrickfirmware to sbyte, now i dont need to change polarization(Reverse attr).

Now I’m analyzing lejos source code to find differences. And I think they are using some filters for gyro.
Maybe this is a problem.

Jacek

Hi
Jacek

The sensor problem has been fixed see this post. Download the lastest DLL to get the fix

Anders