I would like to report a not fully developed idea to make the contact switch on the feet simpler: Using a flexible force sensor stripe (plyon® Medium Sensor) that can be taped around the round foot of the leg provides feedback about contact and force. This approach would be much simpler in comparison to the optical foot contact switch. Problem I see with the flexible force sensor stripe: Its measurement range is dependent on the contact area (which is relatively small at the robot) so it could be not enough for precise measuring the robot’s contact force.
Good idea - you should try it.
We are working on methods to get reliable foot contact estimation without a foot sensor.
It seems that by monitoring the change in motor torque and speed it should be possible.
The main advantage would be the reduced complexity and that there is no need to route the foot sensor wires through the actuator modules.
The drawback is that this won’t work in the singularity (when the knee is fully straightened at touchdown).