Can EV3 giro keep a vehicle level?

[JM1971]

The the film last days on mars there is a rover with self levelling suspension, could the EV3 with giro sensor control 4 sets of actuators to keep a vehicle level?

[DrJB]

Very interesting question/thought. Though, difficult to tell as such spec is not clearly stated on the sensor's description. Might be worthwhile to measure the 'time constant' of such sensor i.e., how fast it responds to inputs. My guess is that the sensor is not sensitive (cannot detect) slow varying changes in tilt. This is not fact, just my gut feeling. Again, best answer is to actually measure such performance/property of the sensor. To keep a vehicle level, might be more effective to use a 'level' sensor (instead of the gyro).

The vehicle in the movie you reference uses actuators (an active suspension) to move the tires up/down as the road profile changes ... Assuming you can measure the vehicle's level ... you need a very fast actuator to keep up with the road's inputs. Not sure the LA's/mLA's are up to the job.

Edited February 22, 2014 by DrJB

[Junpei]

Just use an EV3 servo connected to the suspension using a linkage. It's fast enough you could probably even gear it down.

TLH

[JM1971]

Very good soution so 4 servos for active suspension, a servo for steering, 2 L or XL motors for propusion and maybe skid steering thrown in, I dont have the first clue how the giro works but it needs to work not just sideways but also front to back, so whatever you put the vehicle on it would automatically try to stay level, were not talking williams F1 active suspension here but it should ride over bumps and stay level on inclines as long and its not going too fast for the servos to keep up.

Edited February 22, 2014 by JM1971

[Cwetqo]

I dont know if you tested Gyro Boy from Education set, but it works very fast, certainly faster than motors can react, especially if you plan to use actuators, which need few seconds to react.

Edit: I never tried anything with gyro sensor, but after checking in Education software, it seems that gyro sensor block has just one angle output, which most likely means that It can measure angle on just one axis. That means that two gyro sensors would be needed, placed at 90 degrees to each other, to control movement in both axis.

[peter_m]

I dont know if you tested Gyro Boy from Education set, but it works very fast, certainly faster than motors can react, especially if you plan to use actuators, which need few seconds to react. Other limiting factor could be response time of control program. Gyro boy program is much more complex than I anticipated, with many

Gyro Boy makes a great use of EV3 gyroscope - but keep in mind that it works only in one plane. With one gyroscope you will be able to apply only side leveling and you would need another one if you would also want front/back leveling.

A better alternative would be to use NXT Accelerometer Sensor (http://shop.lego.com/en-PL/Accelerometer-Sensor-2852724?fromListing=listing) as it works in 3 dimensions. I am not sure though if it is compatible with EV3.

Edited February 23, 2014 by peter_m

[JM1971]

I see on the lego site you can buy gyros separately now, I assume ev3 will apply progressive control to the servos so its just a case of writing the program.

Now I have to save up for ev3.