System and method for controlling a maximum vehicle speed for an industrial vehicle based on a calculated load
Controlling a maximum vehicle speed for an industrial vehicle includes determining, by a processor of the industrial vehicle, a torque applied to the traction wheel of the industrial vehicle; converting the torque to an equivalent force value; and determining an acceleration of the industrial vehicle while the torque is applied to the traction wheel. Additional steps include calculating a load being moved by the industrial vehicle, based at least in part on the acceleration and the equivalent force value; and controlling the maximum speed of the industrial vehicle based on the calculated load being moved by the industrial vehicle.
1 . A method for controlling a maximum vehicle speed for an industrial vehicle, comprising:
determining, by a processor of the industrial vehicle, a torque applied to a traction wheel of the industrial vehicle;
determining, by the processor of the industrial vehicle, an acceleration of the industrial vehicle while the torque is applied to the traction wheel;
based at least in part on the acceleration and the torque applied to the traction wheel, calculating, by the processor of the industrial vehicle, a load being moved by the industrial vehicle, wherein calculating the load comprises:
calculating a set comprising at least a minimum number of individual load values of the load being moved by the industrial vehicle in response to the industrial vehicle accelerating above a first predefined value;
averaging the at least a minimum number of individual load values to determine a respective set load value for the set;
collecting, by the processor of the industrial vehicle, a plurality of the set load values of the load being moved by the vehicle, each subsequent set load value being calculated after the industrial vehicle is detected to accelerate below the first predefined value and then accelerating above the first predefined value; and
averaging the respective values of the plurality of set load values to determine the calculated load; and
controlling, by the processor of the industrial vehicle, the maximum speed of the industrial vehicle based on the calculated load being moved by the industrial vehicle.
2 . The method of claim 1 , wherein the load comprises one or more trailers being pulled by the industrial vehicle.
3 . The method of claim 1 , further comprising:
converting, by the processor of the industrial vehicle, the torque applied to the traction wheel to an equivalent force value; and
wherein calculating the load being moved by the industrial vehicle is based at least in part on the equivalent force value.
4 . The method of claim 1 , comprising:
determining, by the processor, the maximum speed of the industrial vehicle based on the calculated load and a grade of a path being traveled by the industrial vehicle.
5 . The method of claim 1 , comprising:
determining, by the processor of the industrial vehicle, a rolling resistance of the industrial vehicle while moving the load; and
wherein calculating the load being moved by the industrial vehicle is based at least in part on the rolling resistance.
6 . The method of claim 1 , comprising:
determining, by the processor of the industrial vehicle, a grade of a path being traveled by the industrial vehicle while moving the load; and
wherein calculating the load being moved by the industrial vehicle is based at least in part on the grade.
7 . The method of claim 1 , wherein each of the individual load values of the load being moved by the industrial vehicle is calculated according to:
total
vehicle
mass
(
TVM
)
=
F
A
9
.
8
V
A
g
+
G
%
+
R
%
where:
F A is an equivalent force value, equivalent to the torque applied to the traction wheel;
R % is a rolling resistance value;
G % is a present grade as a percentage of a surface on which the industrial vehicle is traveling;
VA g is the acceleration of the industrial vehicle in g's; and
the individual load value=TVM−(an empty weight of the industrial vehicle).
8 . The method of claim 1 , wherein each of the individual load values of the load being moved by the industrial vehicle is calculated according to:
TVM
=
(
(
T
C
-
T
I
T
)
×
gearbox
ratio
×
gearbox
efficiency
(
9.8
×
driven
wheel
radius
)
)
V
A
g
+
G
%
+
R
%
.
where:
T c is a torque command;
T IT is an inertial torque;
gearbox ratio is a predetermined gearbox ratio of the industrial vehicle;
gearbox efficiency is a predetermined gearbox efficiency of the industrial vehicle;
driven wheel radius is a radius of the traction wheel;
R % is a rolling resistance value;
G % is a present grade as a percentage of a surface on which the industrial vehicle is traveling;
VA g is the acceleration of the industrial vehicle in g's; and
the individual load value=TVM−(an empty weight of the industrial vehicle).
9 . The method of claim 1 , wherein the industrial vehicle comprises a fork assembly.
10 . The method of claim 1 , comprising:
defining, by the processor of the industrial vehicle, an initial value of the calculated load to be the maximum load the industrial vehicle is designed to move.
11 . The method of claim 1 , comprising:
determining, by the processor of the industrial vehicle, when a lift mechanism of the industrial vehicle is being raised or lowered,
wherein calculating the load being moved by the industrial vehicle based on the acceleration and the torque is not performed while the lift mechanism is being raised or lowered.
12 . The method of claim 1 , wherein calculating a set comprising at least a minimum number of individual load values of the load being moved by the industrial vehicle comprises:
calculating a set comprising a predetermined number of individual load values of the load being moved by the industrial vehicle in response to the industrial vehicle accelerating above the first predefined value and traveling at least a predetermined distance; and
averaging the predetermined number of individual values to determine a respective set load value for the set.
13 . The method of claim 1 , comprising:
determining, by the processor of the industrial vehicle, whether the industrial vehicle has traveled more than a predetermined distance when starting to travel after previously being stopped to allow slack in trailer linkages to be taken up;
wherein calculating the load being moved by the industrial vehicle is delayed until the industrial vehicle is determined to have traveled more than the predetermined distance.
14 . A system for controlling a maximum vehicle speed for an industrial vehicle, comprising:
a memory device storing executable instructions; and
a processor in communication with the memory device, wherein the processor, when executing the executable instructions:
determines a torque applied to a traction wheel of the industrial vehicle;
determines an acceleration of the industrial vehicle while the torque is applied to the traction wheel;
calculates a load being moved by the industrial vehicle based at least in part on the acceleration and the torque applied to the traction wheel, wherein calculating the load comprises:
calculating a set comprising at least a minimum number of individual values of the load being moved by the industrial vehicle in response to the industrial vehicle accelerating above a first predefined value;
averaging the at least a minimum number of individual values to determine a respective set load value for the set;
in response to the acceleration of the industrial vehicle falling below the first predefined value and then accelerating above the first predefined value, collecting a further set load value of the load being moved by the industrial vehicle;
averaging the respective values of the plurality of set load values to calculate the load; and
controlling a maximum speed of the industrial vehicle based on the calculated load being moved by the industrial vehicle.
15 . The system of claim 14 , wherein the load comprises one or more trailers being pulled by the industrial vehicle.
16 . The system of claim 14 , wherein the processor when executing the executable instructions:
converts the torque applied to the traction wheel to an equivalent force value; and
wherein calculating the load being moved by the industrial vehicle is based at least in part on the equivalent force value.
17 . The system of claim 14 , wherein the processor when executing the executable instructions:
determines the maximum speed of the industrial vehicle based on the calculated load and a grade of a path being traveled by the industrial vehicle.
18 . The system of claim 14 , wherein the processor when executing the executable instructions:
determines a rolling resistance of the industrial vehicle while moving the load; and
wherein calculating the load being moved by the industrial vehicle is based at least in part on the rolling resistance.
19 . The system of claim 14 , wherein the processor when executing the executable instructions:
determines a grade of a path being traveled by the industrial vehicle while moving the load; and
wherein calculating the load being moved by the industrial vehicle is based at least in part on the grade.
20 . The system of claim 14 , wherein the industrial vehicle comprises a fork assembly.
21 . The system of claim 14 , wherein the processor when executing the executable instructions:
defines an initial value of the calculated load to be the maximum load the industrial vehicle is designed to move.
22 . The system of claim 14 , wherein the processor when executing the executable instructions:
determines when a lift mechanism of the industrial vehicle is being raised or lowered,
wherein calculating the load being moved by the industrial vehicle based on the acceleration and the torque is not performed while the lift mechanism is being raised or lowered.
23 . The system of claim 14 , wherein the processor when executing the executable instructions:
calculates a set comprising at least a minimum number of individual values of the load being moved by the industrial vehicle by calculating a set comprising a predetermined number of individual values of the load being moved by the industrial vehicle in response to the industrial vehicle accelerating above the first predefined value and traveling at least a predetermined distance; and
averages the predetermined number of individual values to determine a respective set load value for the set.
24 . The system of claim 23 , wherein the processor when executing the executable instructions defines the predetermined number of individual values of the load to be equal to or less than 200.
25 . The system of claim 23 , wherein the processor when executing the executable instructions defines the predetermined number of individual values of the load and a sample rate such that a count of the individual values of the load reaches the predetermined number within 2 seconds from when the count is first incremented.
26 . The system of claim 14 , wherein each of the individual load values of the load being moved by the industrial vehicle is calculated according to:
total
vehicle
mass
(
TVM
)
=
F
A
9
.
8
V
A
g
+
G
%
+
R
%
where:
F A is an equivalent linear force value, equivalent to the torque applied to the traction wheel;
R % is a rolling resistance value;
G % is a present grade as a percentage of a surface on which the industrial vehicle is traveling;
VA g is the acceleration of the industrial vehicle in g's; and
the individual load value=TVM−(an empty weight of the industrial vehicle).
27 . The system of claim 14 , wherein each of the individual load values of the load being moved by the industrial vehicle is calculated according to:
TVM
=
(
(
T
C
-
T
I
T
)
×
gearbox
ratio
×
gearbox
efficiency
(
9.8
×
driven
wheel
radius
)
)
V
A
g
+
G
%
+
R
%
.
where:
T c is a torque command;
T IT is an inertial torque;
gearbox ratio is a predetermined gearbox ratio of the industrial vehicle;
gearbox efficiency is a predetermined gearbox efficiency of the industrial vehicle;
driven wheel radius is a radius of the traction wheel;
R % is a rolling resistance value;
G % is a present grade as a percentage of a surface on which the industrial vehicle is traveling;
VA g is the acceleration of the industrial vehicle in g's; and
the individual load value=TVM−(an empty weight of the industrial vehicle).
28 . The system of claim 14 , wherein the processor when executing the executable instructions determines whether the industrial vehicle has traveled more than a predetermined distance from previously being stopped to allow slack in trailer linkages to be taken up; and wherein calculating the load being moved by the vehicle is delayed until the industrial vehicle is determined to have traveled more than the predetermined distance.
29 . A method for controlling a maximum vehicle speed for an industrial vehicle, comprising:
determining, by a processor of the industrial vehicle, a torque applied to a traction wheel of the industrial vehicle;
determining, by the processor of the industrial vehicle, an acceleration of the industrial vehicle while the torque is applied to the traction wheel;
based at least in part on the acceleration and the torque applied to the traction wheel, calculating, by the processor of the industrial vehicle, a load being moved by the industrial vehicle; and
controlling, by the processor of the industrial vehicle, the maximum speed of the industrial vehicle based on the calculated load being moved by the industrial vehicle,
wherein calculating the load comprises:
calculating a set comprising a predetermined number of individual load values of the load being moved by the industrial vehicle in response to the industrial vehicle accelerating above a first predefined value and traveling at least a predetermined distance; and
averaging the predetermined number of individual values to determine a respective set load value for the set;
detecting, by the processor of the industrial vehicle, a first operating condition that comprises:
a) an acceleration of the industrial vehicle is less than the first predefined value, and
b) a speed of the industrial vehicle is less than a second predefined value;
subsequent to the first operating condition, determining, by the processor of the industrial vehicle, a second operating condition comprising the industrial vehicle, within a predefined time period after the first operating condition:
a) begins accelerating again above the first predefined value, and
b) has traveled the predetermined distance;
in response to occurrence of the first operating condition and occurrence of the second operating condition within the predefined time period after the first operating condition, collecting, by the processor of the industrial vehicle, a further set load value of the load being moved by the industrial vehicle; and
averaging the respective values of the plurality of set load values to calculate the calculated load.
30 . A system for controlling a maximum vehicle speed for an industrial vehicle, comprising:
a memory device storing executable instructions; and
a processor in communication with the memory device, wherein the processor, when executing the executable instructions:
determines a torque applied to a traction wheel of the industrial vehicle;
determines an acceleration of the industrial vehicle while the torque is applied to the traction wheel;
calculates a load being moved by the industrial vehicle based at least in part on the acceleration and the torque applied to the traction wheel; and
controls a maximum speed of the industrial vehicle based on the calculated load being moved by the industrial vehicle;
wherein the processor, when executing the executable instructions to calculate the load, further:
calculates a set comprising a predetermined number of individual values of the load being moved by the industrial vehicle in response to the industrial vehicle accelerating above a first predefined value and traveling at least a predetermined distance; and
averages the predetermined number of individual values to determine a respective set load value for the set;
detects a first operating condition that comprises:
a) an acceleration of the industrial vehicle is less than the first predefined value, and
b) a speed of the industrial vehicle is less than a second predefined value;
subsequent to the first operating condition, determines a second operating condition comprising the industrial vehicle, within a predefined time period after the first operating condition:
a) begins accelerating again above the first predefined value, and
b) has traveled the predetermined distance;
in response to occurrence of the first operating condition and occurrence of the second operating condition within the predefined time period after the first operating condition, collects a further set load value of the load being moved by the industrial vehicle; and
averages the respective values of the plurality of set load values to calculate the calculated load.