# A Neuro-Prosthetic Device for Substituting Sensory Functions during Stance Phase of the Gait
## 3 Results and Discussion
### Results of Balancing Strategies
All three joints angles are decreased during the stimulation based on this strategy. We see appropriate accuracy for IMUs to find joint angles by comparison of data from IMUs and potentiometers at robot joints. Figure 19: Stimulation results based on strategy #2 (**a**) pelvic orientation, (**b**) robot hock joint response, (**c**) comparison of angles found from IMU readings with potentiometers. Figure 18: Stimulation results based on strategy #2 (**a**) pelvic orientation, (**b**) robot knee joint response, (**c**) comparison of angles found from IMU readings with potentiometers. Figure 21: Stimulation results based on strategy #3 (**a**) pelvic orientation, (**b**) robot knee joint response, (**c**) comparison of angles found from IMU readings with potentiometers. Figure 20: Stimulation results based on strategy #3 (**a**) pelvic orientation, (**b**) robot hip joint response, (**c**) comparison of angles found from IMU readings with potentiometers. To test strategies 4 and 5, we apply a falling command to the right leg of our robot using Teensy #1. As soon as the IMU reads numbers more than 10 degrees, Teensy calculates a new stimulation command based on our proposed strategies. Figures 23-25 show experimental results for strategy #4 with pelvic orientation changes in (a) and joint response measured by IMUs in (b). We see that appropriate stimulation can push the pelvis up and balance the body. The same results for strategy #5 have been shown in Figures 26-28. Figure 12:0 Stimulation results based on strategy #4 (**a**) pelvic orientation, (**b**) robot knee joint response. Figure 12:1 Stimulation results based on strategy #4 (**a**) pelvic orientation, (**b**) robot hock joint response. Figure 12:2 Stimulation results based on strategy #5 (**a**) pelvic orientation, (**b**) robot knee joint response. Figure 12:3 Stimulation results based on strategy #5 (**a**) pelvic orientation, (**b**) robot hip joint response. The final pelvis orientation error for each strategy has been listed in Figure 12:4 As shown, the maximum error from our system and algorithm is 2.69 degrees. This orientation error, which is related to strategy #3, is within the normal range for pelvis orientation of the healthy dog. The smallest error is about 1.75 degrees, related to strategy #4. From these results, we conclude that our system is able to successfully apply voltage/charge until it balances the dog body and returns the pelvis to normal and acceptable orientation. In terms of the control system algorithm, none of these strategies show a clear advantage, since the final pelvis orientation error is small in all cases; however, for helping an actual disabled animal, the suitable strategy must be selected based on the remaining abilities of the dog after injury. For example, many of the injured individuals are still able to maintain 140 degrees for knee joint angles during walking. For these dogs, strategy #1 is the most suitable method of balancing since less electrical stimulation to muscle nerves is needed for balancing control. In fact, limited walking abilities of animal can play an important role in balancing. For dogs with more serious injuries, knee joint muscles may not be able to maintain a fixed angle at the knee joint. Strategy #2 or #3 should be selected for these dogs to help them stand and walk by applying electrical charges to suitable nerves of muscles supporting the knee joint.