How to read/calculate the stiffness setting of a joint on a NAO robot

manpreet Best Answer 3 years ago

I have a C++ program that communicates with the Naoqi DCM, sending commands and reading status information, but I cannot find a way to read a joint's stiffness setting directly.

Naoqi has the following ALMemory keys for a particular joint, left shoulder pitch in the example below.

Device/SubDeviceList/LShoulderPitch/Position/Actuator/Value
Device/SubDeviceList/LShoulderPitch/Position/Sensor/Value
Device/SubDeviceList/LShoulderPitch/ElectricCurrent/Sensor/Value
Device/SubDeviceList/LShoulderPitch/Temperature/Sensor/Value
Device/SubDeviceList/LShoulderPitch/Hardness/Actuator/Value
Device/SubDeviceList/LShoulderPitch/Temperature/Sensor/Status

Whilst I am able to write to the above actuators and read from the sensors, I need to determine the joint's stiffness setting, however Hardness is a write only actuator and cannot be read.

I've looked at the values that the ElectricCurrent sensor returns and have determined that it alone does not give the desired result. Even with stiffness set to maximum, if the arm is at its destination pose and there is no displacing torque force, the ElectricCurrent reports zero current for the joint. Thus you cannot assume that stiffness is off when there is no current.

Anyone know how to determine the stiffness setting of a joint without using motionProxy.getSummary()?