[ODE] Hinge torque

[Ishimaru Kazuhisa]

Hello,

I am a Japanese student. I use ODE for simulating a multi-legged robot which has many hinge joints. 
I want to optimize its performace in consideraton of its energy consumption. To calculate its energy
consumption, I need angular velocity and torque which are output by hinge joint. The former is easy 
to get by using dJointGetHingeAngleRate(), but the latter is not. How can I get the torpue output?

Thanks 

Kazuhisa