I’ve added a force sensitive resistor to use a force sensor to the heel of a shoe to detect when the user’s body weight is shifted forward off the heel. During human gait, the rear heel of the rear leg that is about to swing forward comes up first. In the case of my Mom, she has the ability to pull her heel up on her right leg (her weak leg) and so now we can sense this w/ the FSR and trigger the stepping pattern in the exoskeleton knee and hip flexor joints with the linear actuators. If steady pressure is sensed by the FSR connected to the microcontroller (using Arduino) then the sequence will not engage.

Here is a video of me testing the heel sensor.

I’m thinking too that it might be good to add an additional check sensor. Perhaps another FSR to read hand squeeze on the walker or an actual trigger button. This might be necessary because if the user doesn’t wish to initiate that walking step but shifts her body weight while engaged in the suit a certain way the FSR reading could improperly signal a walking step. Another thought I had is to determine the position of the left foot relative to the right foot. Because if we know that, we know that if the left foot is in front of the right then that’s another enforcing reading that a full step is desired with the right leg. Whereas if we know that the left foot is next to or behind the right, a full step most likely wouldn’t be desired. It’s reasonable to conclude that the right step wouldn’t be desired in the side-by-side scenario in my Mom’s case is again because the left side is the stronger side and so therefore would be the leading side.

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