Robust Hybrid Controller Design to Stabilise an Underactuated Robot Vehicle under Various Input

Table 4

The utilised terms and their definitions [35].

Variables and Units	Description
(m)	Distance from the centre of mass to the payload
	Distance from the centre of mass to the upper part of 2^nd link
	Linear actuator position
	The half-length of the 1^st link
	The separating two wheels’ distance
	The displacement of the actuator
	The 1^st link mass
	The motor mass that drives the 2^nd link
	The lower-upper parts mass of the 2^nd link
	Linear actuator mass
	Mass of the payload
	Mass of the wheels
,	Torques driving left-right wheels
	The motor torque
	The linear actuator force
	The linear actuator frictional force
	The external force
	The angle of the 1^st link
	The angle of the 2^nd link
	The angle measured around the -axis
,	The angular displacement of both wheels
	Mass moment of inertia of the 1^st link
	Mass moment of inertia of the 2^nd link upper-lower parts
	The actuator’s mass moment of inertia
	The payload’s mass moment of inertia
	Both wheels’ mass moment of inertia
	The intermediate body’s mass moment of inertia