Table 6 Dynamic gaits and control methods of selected legged robots

Dynamics-based control

Quadruped [85]

38

2.2

0.88

Trot

SLIP

2.9

1.53

Bound

SLIP

Minitaur [56, 96]

5

0.8

0.374

Pronk

SLIP

1.45

1.23

Bound

SLIP

SCOUT II [97]

20.865

1.3

0.53

Bound

SLIP

BigDog [47]

109

3.1

0.98

Bound

‒

2

0.41

Trot

‒

KOLT [43]

80

1.1

0.18

Trot

SLIP + Fuzzy Control

Hexbot-IV [6]

268

0.55

0.04

Trot

SLIP for hexapod tripod gait

HyQ [99]

70

1

0.15

Trot

VMC

HyQ [48, 162]

70

2

0.6

Trot

Active impedance control

Cheetah 1 [112,113,114]

39.406

6

7.34

Gallop

Proprioceptive impedance control

Cheetah 2 [2, 22, 54]

34.4^*

6.4

7.1

Bound

Direct control of ground reaction force

Cheetah 2 [1]

34.4^*

2.4

1

Jump over obstacles

MPC

Cheetah 3 [24, 100, 101]

45

1.2

0.216

Trot

MPC

1.7

0.434

Flying-trot

MPC

3

1.35

Gallop

MPC

StarlETH [20, 102,103,104]

25

0.7

0.15

Trot

WBC

ANYmal [10, 87]

30

1

0.204

Trot

WBC

Model-free control

Cheetah-cub [40]

1.1

1.42

1.3

Trot

CPG

Tekken 1[40, 105, 106]

3.1

1

0.49

Trot

CPG

1.1

0.59

Bound

CPG

Tekken 2 [40, 107]

4.3

0.95

0.37

Trot

CPG

HyQ [17]

70

0.35

0.104

Trot (On unexpected terrains)

CPG-Task space trajectory generation

Baby elephant [108]

130

0.5

0.035

Trot

CPG

Minitaur [110]

5

0.6

0.21

Trot

Sim-to-real RL

1.18

0.815

Gallop

Sim-to-real RL

ANYmal [3]

30

1.5

0.459

Flying-trot

Sim-to-real RL