Table 3 Parameters for the design of a multifunctional robotic end-effector
Notation | Description |
|---|---|
F g | Gripping force of the multifunctional robotic end-effector |
M | Mass of the object to be grasped by the multifunctional robotic end-effector |
g | Acceleration due to gravity |
μ | μ = coefficient of static friction between the object to be gripped and the multifunctional robotic end-effector = |
FS | Factor of safety = 1.5 |
ω = ω 1 and ω 2 | Relative angular speed of the worm and gear of the multifunctional robotic end-effector |
n | Rotational speed of the worm of the multifunctional robotic end-effector |
V | Linear speed of the worm of the multifunctional robotic end-effector |
r | Radius of the worm of the multifunctional robotic end-effector |
P | Power dissipated by the multifunctional robotic end-effector in carrying out a RVS machine maintenance task |
N 1 and N 2 | Rotational speed of the worm and gear of a multifunctional robotic end-effector |
T 1 and T 2 | Number of teeth in the worm and gear of a multifunctional robotic end-effector = |
i | Worm–gear ratio |
C | Assumed centre distance of the worm–gear of the multifunctional robotic end-effector |
d 1 and d 2 | Diameters of the worm and gear of the multifunctional robotic end-effector |
P 2 | Circular pitch of the gear |
m | Module |
P a | Axial pitch of the worm |
L | Lead of the worm |
N tw | Number of the teeth on the worm |
λ and Ψ | Lead angle and helix angle |
L w | Axial length of the worm |
L screw | Total length of the lead screw |
V 1 and V 2 | Linear speed of the worm and gear of the multifunctional robotic end-effector |
r 1 and r 2 | Radius of the worm and gear of the multifunctional robotic end-effector |
V s | Sliding velocity |
F 1t, F 2t, F n and F d | Tangential forces, normal force and total force acting on the worm |
F a and F r | Thrust or axial force and radial force |
\({\o}_{\text{n}}\) | Pressure angle |
F b | Bending fatigue strength of the worm–gear of the end-effector |
F w | The maximum allowable value of dynamic load under surface fatigue condition |
σ b | Permissible bending stress in bending fatigue for worm–gear material |
b | Face width |
Kw | Material and geometry factor of the worm–gear |
Y | Modified Lewis form factor obtained from a worm–gear catalogue |
ƞ | Efficiency of the worm–gear module |
f | Coefficient of friction acting on the worm–gear module |
H g | Heat dissipation of the worm–gear |
A | Surface area |
C | The distance between the shafts of the duplex worm wheel of end-effector |
C H | Heat transfer coefficient |
T o | Lubricating oil temperature of the worm–gear |
T a | Ambient air temperature |
σ a and σ max | Nominal and maximum bending stresses acting on the bolt socket module of the robotic end-effector |
τ a and τ max | Nominal and maximum torsional stresses acting on the bolt socket module of the robotic end-effector |
Mc | Turning effect on the M-20 bolt |
T | Torque on the bolt |
I | Inertia of the object |
d | Diameter of the bolt socket module |
K t and K ts | Theoretical stress concentration factors |
\(m_{{{\text{cyl-rod}}\;{\text{at}}\; 0\;{\text{str}}}}\) | Mass of the cylinder rod at zeroth stroke |
\(m_{\text{cyl-rod}}\) | Mass of the cylinder rod |
\(m_{\text{cyl-rod/mmstroke}}\) | Mass of the cylinder rod per mm of stroke |
\(m_{\text{ext}}\) | External mass = mass of the screen panel pin on the RVS machine |
\(F_{\text{fr-ext}}\) | External frictional force in N |
\(F_{\text{ham}}\) | Hammering force |
\(F_{\text{un-pin}}\) | Unpinning force |
\(F_{\text{x,ext}}\) | External force |
\(U_{\text{m}}\) and \(V_{\text{m}}\) | Initial and final linear speed of the electric motor powering the electric cylinder actuator |
a | Acceleration of the electric motor |
s | Travel distance of the piston of the electric cylinder actuator |