Table 2.

Subtasks against engagement of individual actuators

Subtask	Associated DOFs	Right motor ${\mathit{\tau }}_{\text{R}}$	Left motor ${\mathit{\tau }}_{\text{L}}$	Linear actuator I, $F_1$	Linear actuator II, $F_2$
Moving and picking	${\mathit{\delta }}_{\text{L}}$, ${\mathit{\delta }}_{\text{R}},\mathit{\theta }$	✓	✓	✕	✕
IB extension	${\mathit{\delta }}_{\text{L}}$, ${\mathit{\delta }}_{\text{R}},\mathit{\theta },h_1$	✓	✓	✓	✕
Extension: end effector	${\mathit{\delta }}_{\text{L}}$, ${\mathit{\delta }}_{\text{R}},\mathit{\theta },h_2$	✓	✓	✕	✓
Reverse: end effector	${\mathit{\delta }}_{\text{L}}$, ${\mathit{\delta }}_{\text{R}},\mathit{\theta },h_2$	✓	✓	✕	✓
IB contraction	${\mathit{\delta }}_{\text{L}}$, ${\mathit{\delta }}_{\text{R}},\mathit{\theta },h_1$	✓	✓	✓	✕
Placing the object	${\mathit{\delta }}_{\text{L}}$, ${\mathit{\delta }}_{\text{R}},\mathit{\theta },h_2$	✓	✓	✕	✕