Blog #7

From the period of October 28 to November 18, Team 8 was able to obtain the remaining data logging tools needed for the testing trials with the implementation of the Wheelchair Lifting Aid. These being the inclinometer and the strain gauges displayed in Fig. 1 and 2. 

 

Fig. 1 Inclinometer 

Fig. 2 Strain Gauges

 The inclinometer was used to measure the inclination angle of the caregiver during the lifting process, whereas the strain gauges were used to measured the deformation, if any, in the lifting system structure and wheelchair frames when subjected to heavy loads. Fig. 3 displays the experiment being carry out by the members of the team. It is to be noted that the caregiver was the same subject, whereas there were five different individuals as the patient throughout the experimental trials. The purpose for having several different patients is to acquired a large spectrum of physicals traits, and to study how these traits affect the angle of inclination, lumbar force and vertical lifting force exerted by the caregiver during the lifting process.

Fig.3 Experimental trials with WLA

Following, Fig. 4-6 display the placement locations for the strain gauges. Such locations were selected based on the Finite Element Analysis previously performed on the device. That is, these location were shown to be more exposed to stress and deformation. 

Fig. 4

Fig. 5

Fig. 6

Following, all data obtained from these testing trials was plotted and compared against the data previously obtained where the WLA was not implemented during the lifting process. Such plots can be seen on Fig. 7-9.

Fig. 7 Lumbar force comparison.

Fig. 8 Lifting Force comparison.

Fig. 9 Caregiver's Angle of inclination comparison.

As it can be observed from the plots above, the implementation of the WLA does have a significant impact in decreasing the angle of inclination, the lumbar force as well as the vertical lifting force exerted by the caregiver. By implementing the WLA the three parameters decreased to way below the lower limit initially aimed by the team. Thus, validating the projected results in the theoretical analysis performed, during the Spring of 2023.

Lastly, Fig. 16 and 17 display the current status of the prototype. As it can be observed the WLA system has been fully assembled and installed in the wheelchair frame. With the wheelchair seat reaching the projected angle of 60 degrees from the horizontal.

                                        Fig. 10                                         Fig. 11

Finally, the improvements to be made to the WLA include the modification of the seat. That is the plywood seat is to be padded in order to increase the friction and decrease the possibility of slippage of the patient while the seat is being lifted. Another reason for the seat padding is to eliminate any pinch-points in the plywood. In addition, back anti-tippers are to be added to the back of the chair to avoid both slippage and tip of the wheelchair during the lifting process. The anti-tippers can be seen on Fig. 12.

                                                       Fig. 12 Wheelchair Anti-tippers

Lastly, the current draft of Team's 8 Poster is displayed on Fig. 13.

                                                    Fig. 13 Poster Draft