Qualitative results. Both training and testing categories across four distinct scenarios (edge, slot, slope, and wall) are tested. Affordance maps illustrate potential effective interaction areas. It can be observed that PreAfford yields reasonable pre-grasping and grasping strategies across different object categories and scenes on both seen and unseen objects.
Multi-feature environment adaptability. (a) Rendered image of the multi-feature environment. (b) Point cloud and affordance hot map, showcasing reasonable pre-grasping policies for objects at different locations.
Table: Comparison with baselines. Pre-grasping significantly improves grasping success rates by 52.9%. Closed-loop strategy further improves success rates by 16.4% over all categories. A push in a random direction and a push towards the geometric center are also included as baselines.
Setting |
Train object categories |
Test object categories |
Edge |
Wall |
Slope |
Slot |
Multi |
Avg. |
Edge |
Wall |
Slope |
Slot |
Multi |
Avg. |
W/o pre-grasping |
2.3 |
3.8 |
4.3 |
3.4 |
4.0 |
3.6 |
6.1 |
2.3 |
2.9 |
5.7 |
6.0 |
4.6 |
Random-direction Push |
21.6 |
10.3 |
6.4 |
16.8 |
18.1 |
14.6 |
24.9 |
17.2 |
12.1 |
18.4 |
23.0 |
19.1 |
Center-point Push |
32.5 |
23.7 |
40.5 |
39.2 |
39.0 |
35.0 |
25.1 |
17.4 |
28.0 |
30.2 |
21.5 |
24.4 |
Ours w/o closed-loop |
67.2 |
41.5 |
58.3 |
76.9 |
63.6 |
61.5 |
56.4 |
37.3 |
62.6 |
75.8 |
55.4 |
57.5 |
Ours |
81.4 |
43.4 |
73.1 |
83.5 |
74.1 |
71.1 |
83.7 |
47.6 |
80.5 |
83.0 |
74.6 |
73.9 |
Real-world experiment figures. Four pre-grasping cases with their affordance map are demonstrated: (a) Move a tablet to table edge, (b) Push a plate towards wall, (c) Push a keyboard up onto a slope and (d) Slide a tablet into a slot.
Table: Real-world experiment results. For both direct grasping (without pre-grasping) and grasping after pre-grasping cases, we perform two experiments on each object in each experimental scene, success rates are shown below as percentages.
Setting |
Seen categories |
Unseen categories |
Edge |
Wall |
Slope |
Slot |
Multi |
Avg. |
Edge |
Wall |
Slope |
Slot |
Multi |
Avg. |
W/o pre-grasping |
0 |
0 |
0 |
0 |
0 |
0 |
10 |
0 |
5 |
0 |
0 |
3 |
With pre-grasping |
70 |
45 |
80 |
90 |
85 |
74 |
80 |
30 |
75 |
90 |
85 |
72 |