Demonstration (200*):

The riser is 20 cm. 

Hop simulation which can jump over cables or something:

Blue and red curves show the trajectories of upper and lower bodies, respectively. From the red curve after the landing, we can see that there was no impact.  

Challenge! 27cm-riser jump:

This robot, 2-DOF spring-mass system, vibrated three times during a hop.

Climbing down ( by Kobayashi 2013):

During takeoff, it is difficult to control the attitude because the front wheels lose the reaction from the floor first. Zero-impact landing is achieved in the condition that the attitude is correct. 

m1:1.1kg, m2:2.25kg, k=1200 N/m, h:0.11 m

Continuous climbing: 

m1:2.5kg,m2:1.2kg,h:0.12m,k:2000N/m