Dear Zhongmou,

if you want to find the resultant force and torque under an equilibrium condition, you can constrain your system by a fixed joint, between the ground and the system itself, located at the origin of your body frame.

After you have run a simulation, you can find, in the post-processor, the components and the magnitude of the force and the torque performed by the fixed joint. These are the net force and torque of your loaded system.

This can be done simply by using load cell at the region you want to measure the values of forces ,and then by Knowing the value of arms can you found the value of torques.Also if you knee the value of power and the value of rpm then you can found the torques values .See the following link Zhongmou

http://www2.myoops.org/cocw/mit/NR/rdonlyres/Mechanical-Engineering/2-007Design-and-Manufacturing-ISpring2003/3E712E6A-CF8B-48B4-8267-A5999A5856A0/0/motorcalc.pdf

http://pages.mtu.edu/~wjendres/ProductRealization1Course/DC_Motor_Calculations.pdf

Guilia is right. If aTorque or force is applied to the bot it will never reach equilibrium. You have to put a fixed joint which will give the reactions to these applied forces. Since it is a reaction its magnitude will be opposite in sign

Thanks to your help, I used the fixed joint to conect my robot to the ground. Then I am able to measure the resultant forces and torques finally. Thanks again.

https://www.researchgate.net/post/How_to_apply_3D_forces_on_a_rotational_body_in_ADAMS

http://sbel.wisc.edu/Courses/ME451/2013/Assignments/ADAMS_4.pdf

http://mech.unibg.it/~lorenzi/VD&S/DispenseMBlundell/ADAMS%20Summary%20User%20Guide%20(1).DOC

https://paws.kettering.edu/~amazzei/student_guide.pdf

https://www.researchgate.net/post/How_to_apply_3D_forces_on_a_rotational_body_in_ADAMS

Simple way is that add a fixed joint constraint at the desired location and measure the forces and torques at the fixed joint.

You should constraint your system by a joint, between the ground and the system.