Week 4: Modeling

So far, we've come up with a number of ways to control the Orthoglove. First, we thought of using flex sensors attached to the glove fingers. However, we realized that the flex sensors only sense position and no torque or force. Then, we came across some serious looking robot servos called Dynamixels that have a variety of sensing capabilities, including torque. But after doing some research, we heard from hobbyists that the Dynamixels work best for measuring static torque only. We need dynamic and static torque measurements.

After asking for advice from our fellow engineers, we are deciding to give force-sensing resistors (FSR) a try. The concept is simple: FSRs placed above and below a patient's fingertip will be able to sense the pressure of the finger that is caused by an attempt to open or close the hand. Once the servo comes in to help, the sensor will dynamically read the pressure, allowing us to program the glove to stop moving at a certain reading from the sensor.

With this FSR design, our physical model is still the same as before with the addition of the FSRs on a finger. This week, we also produced a rough model of the glove shown here (fig. 1):

Figure 2. A rough model of the Orthoglove.

Here, the stretchy, blue glove is placed inside a grey colored wrist support. This support gives us a place to mount the servo (maroon) and the Arduino UNO module (cyan). A small FSR (yellow) is also placed on one of the fingers. Now off to prototype building!