Message thread on Webots Programming

Truck won't go faster than 35km/h with torque control modeby Erkan Tuncali (Webots PRO - 5) 2017-12-27 22:42:45
Mac OSX, Webots 2018a Pro.

I am trying to drive the truck in torque control mode. I am applying full throttle and upshifting the gears when the rpm saturates. However, I couldn't make the truck go faster than 35 km/h.
Could you please confirm that you can drive the truck (standard semi-truck with trailer) faster in torque control mode? If so, could you share optimal gear change rpms?

Thanks.
Re: Truck won't go faster than 35km/h with torque control modeby David Mansolino (Webots PRO - 341) 2017-12-30 11:24:22
Dear Erkan,

Our support team is currently on holiday until the 3rd of January.
We will answer to your question as soon as we are back.

Sincerely,
David
Re: Truck won't go faster than 35km/h with torque control modeby David Mansolino (Webots PRO - 341) 2018-01-03 09:23:33
Dear Erkan,

Our model of truck is new and we haven't completely calibrated the torque control mode, this is why you get such unrealistic behavior.

In order to fix the issue you simply have to edit it's PROTO file (located in WEBOTS_HOME/projects/vehicles/protos/generic/Truck.proto).
You simply need to add the missing field (all the fields are documented here: https://www.cyberbotics.com/doc/automobile/car).
Basically, the two interesting fields to add are:
- engineFunctionCoefficients: defines the torque function of the engine.
- gearRatio: defines the coefficients and number of gears.

If you manage to get realistic value do not hesitate to send them to us so that we can fix the issue for the next release of Webots. And if you can't do not hesitate to ask us for help.

Sincerely,
David
Re: Truck won't go faster than 35km/h with torque control modeby David Mansolino (Webots PRO - 341) 2018-04-20 08:59:55
Dear Erkan,

Just to let you know that we did fix the issue in our development environment and it will be available from Webots R2018b which should be released in a few months from now.

Sincerely,
David
Re: Truck won't go faster than 35km/h with torque control modeby Mojtaba Zarei (20) 2018-12-05 00:46:58
Dear David,

I want to control one of the vehicles in Webots in torque mode (LincolnMKZ). When I use setThrottle(1) nothing will happen! Should I import some other libraries but Driver? How to enable control in torque for the simulation?

Update: I found setGear field to do so.

Best,
Mojtaba
Re: Truck won't go faster than 35km/h with torque control modeby Mojtaba Zarei (20) 2018-12-05 01:38:34
I have the same problem. Changing the gear in LincolnMKZ will lead to decrease the speed and maximum speed will not exceed 45km/h. I added engineFunctionCoefficients manually from the BMW model, but it does not work.

How can I solve this?

Best,
Mojtaba
Re: Truck won't go faster than 35km/h with torque control modeby David Mansolino (Webots PRO - 341) 2018-12-05 12:58:57
Dear Mojtaba,

You are right, you don't need additional libraries but you need to engage a gear using the setGear function.

About your issue with the LincolnMKZ, it is a good starting point to copy the engineFunctionCoefficients from the BMW, but this coefficients are car specific, and may need to be adapted as the mass of the vehicle is not the same.
Furthermore, you probably also need to specify the 'gearRatio'.

I advise you to specify the 'gearRation', and then if it still doesn't work, try increasing the second value of the 'engineFunctionCoefficient' field.

Finally, make sure to not switch gear too quickly, as it is normal that if you switch to a high gear while the car speed is low the motor won't be able to produce enough torque to accelerate the vehicle.

Sincerely,
David
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