To verify the abilities of the developed stair-climbing crawler with powder-filled belts,
comparison experiments between a crawler with powder-filled belts, a crawler with
grouser-attached tracks (Figure 29) and a crawler with urethane rubber blocks (Figure 30)
were performed. The stairs used in these experiments have steps of 270 mm in length and
150 mm in height having R2 edges that are sharper than ordinary stairs. All of the crawlers
were able to ascend and descend the stairs. In addition the traction forces, which give an
indication of the margin of stability and payload, were measured. The results of traction
forces are shown in Table 1. It was observed that the developed crawler with powder-filled
belts can generate a large traction force that is approximately twice as large as that of the
crawler with urethane rubber blocks. The crawler with grouser-attached tracks was able to
generate large traction forces when the grousers achieve a good grip on the stair edges.
However, as mentioned above, slippage or spinning has been observed when the support
point changes. Figure 31 shows the measurement of the pitching angle of the inclination
while ascending the stairs. The crawler with grouser-attached tracks generates a larger
change in inclination angle than the crawlers with powder-filled belts and urethane rubber
blocks.