User training 142

Even when a product design for a given user segment is ready, the users may require training to benefit from the unique features of the design. Even when a variety of shapes is available for a spoon, adaptations needed for eating may still be overwhelming for patients suffering from rheumatoid arthritis or aged people having weak grips. An occupational therapist can help train these people. However, this would require that products are readily available in the market. In the absence of a suitable product, it might be difficult for an occupational therapist to train this user segment. Virtual reality environment can be used to efficiently train these users. Various shapes discussed in Section 7.3 can be used to assess how a user eats his/her food and determine which design will work for a particular user or a set of users. At the same time, an industrial designer can have better understanding of the difficulties of the user group. This can help the industrial designer to come up with better design after receiving valuable inputs from the users.

A major challenge for patients of rheumatoid arthritis or aged people is to eat food with a spoon without spilling it. There are primarily two reasons for spilling food from the spoon; tilting of spoon and shaking of hands while eating with a spoon. Virtual reality environment can provide various scenarios in which a user can interact with spoon while eating food. A variety of spoons developed during the interactive design phase can be

used to determine the best fit for the user.

In the simulation study, different scenarios were considered, which included different angle of tilt for the spoon and shaking of hands. Acceleration was imparted to spoon to simulate shaking of hands. When the spoon gets tilted, jelly may start spilling out of the spoon. A larger tilt will increase the rate of spilling of jelly. However, by practicing with the virtual spoon, a user can be trained to eat without spilling food. Figure 7.18(a) shows the interaction of spoon and food to simulate a user tilting his/her spoon while eating food. Different angle of tilt were considered which resulted in spilling of jelly by different magnitudes. Figure 7.18(b) shows spilling of jelly when the spoon was tilted by ten degrees. The spilling of jelly increased with increased angle of tilt as shown by Figure 7.18(b-d). Figure 7.18(e-h) show the side view of the spoon and jelly.

(a) Jelly on spoon (b) Jelly spills out of spoon when spoon

is tilted by 10 degrees

(c) Jelly spills out of spoon when spoon

is tilted by 20 degrees

(d) Jelly spills out of spoon when spoon

is tilted by 30 degrees

(e) Side veiw of the

jelly on spoon (f) Side view of the spilling jelly, when the spoon tilted by

10 degree

(g) Side view of the spilling jelly, when

the spoon tilted by 20 degree

(h) Side view of the spilling jelly, when

the spoon tilted by 30 degree

Figure 7.18 Simulation of food (jelly) in a spoon when the spoon is tilted by different degrees.

The spilling of spoon gets aggravated when the tilting of spoon is accompanied by the shaking of hands while eating with a spoon. By incorporating the acceleration to the spoon and eventually to the food, both the tilting of spoon as well as shaking of hands can be simulated. Figure 7.19(a) shows the jelly on the spoon bowl. Its side view is shown in Figure 7.19(e). If the user tilts the spoon (anti-clockwise rotation of the spoon when seen from the side of the handle of the spoon) and his/her hands are shaking in the same direction, the jelly will experience force due to its own weight as well as due to the inertial forces. Figure 7.19(b and f) show the result of simulation. It is clear from the figure that shaking of hand exacerbates the slipping of jelly from the spoon. However,

when the shaking of hands happened in the transverse direction, the jelly slipped to lesser extent as shown in Figure 7.19(c and g).

(a) Jelly on spoon (b) Jelly spills out of spoon when spoon is

tilted by 30 degrees and the user's hand is

shaking in the same direction

(c) Jelly spills out of spoon when spoon

is tilted by 30 degrees and the

user's hand is shaking in the transverse direction

(d) Jelly spills out of spoon when spoon

is tilted by 30 degrees sideways and the user's hand

is shaking in the same direction

(e) Side veiw of the

jelly on the spoon (f) Side view of the spilling jelly (g) Side view of the spilling jelly (h) Side view of the spilling jelly

Figure 7.19 Simulation of food (jelly) in a spoon when the spoon is tilted by different degrees and the hand of the user is shaking.

In the same way, when the tilting and the shaking of hand happens in transverse direction (along the major axis of the handle of the spoon), the jelly slips and starts falling down from the side. This is shown in Figure 7.19(d and h). At this point if an industrial designer concludes that the user cannot eat without the tiling and shaking of hands, the spoon design can be reviewed. Some modification such as raising one side of

the spoon bowl or tilting the bowl part of the spoon in the other direction can be carried out at this stage.