Backward movement control device for articulated vehicle, computer-readable medium storing backward movement control program for articulated vehicle, and backward movement control method for articulated vehicle
View Patent ↗A backward movement control device performs a backward movement control of an articulated vehicle including a tractor that includes steered wheels and a trailer towed by the tractor. The tractor is equipped with a steering control device that executes feedback control for causing a steered angle of the steered wheels of the tractor to follow a target steered angle. The backward movement control device includes a control unit configured to calculate the target steered angle such that a virtual steered angle follows a target virtual steered angle when a backward movement operation of the articulated vehicle is performed. The virtual steered angle is a steered angle of steered wheels that are virtually present in the trailer if the trailer is regarded as a rigid vehicle. The target virtual steered angle is a target value of the virtual steered angle that is set through a specific operation by an operator.
1 . A backward movement control device for an articulated vehicle, the articulated vehicle including a tractor including steered wheels that change a traveling direction of the articulated vehicle and a trailer towed by the tractor, wherein
the tractor is equipped with a power steering device, including a motor, configured to execute feedback control for causing a steered angle of the steered wheels to follow a target steered angle,
the backward movement control device includes one or more processors configured to calculate the target steered angle by executing feedback control for causing a virtual steered angle to follow a target virtual steered angle in response to a backward movement operation of the articulated vehicle being performed,
the virtual steered angle is a steered angle of steered wheels that are virtually present in the trailer under an assumption that the trailer is a rigid vehicle separated from the tractor,
the target virtual steered angle is a target value of the virtual steered angle that is set through a specific operation by an operator,
the virtual steered angle is an internal controlled variable of the one or more processors, and
the target steered angle is an output of the feedback control for causing the virtual steered angle to follow the target virtual steered angle.
2 . The backward movement control device for the articulated vehicle according to claim 1 , wherein
the tractor includes a dial that is operable by the operator,
the specific operation is an operation of the dial,
the one or more processors are further configured to:
set the target virtual steered angle based on an operation amount or an operation position of the dial, and
calculate the target steered angle by executing feedback control for causing the virtual steered angle to follow the set target virtual steered angle.
3 . The backward movement control device for the articulated vehicle according to claim 1 , wherein the one or more processors are further configured to:
calculate a target state quantity through execution of feedback control for causing the virtual steered angle to follow the target virtual steered angle, the target state quantity being a target value of a state quantity that reflects a turning state of the tractor; and
calculate the target steered angle through execution of feedback control for causing the state quantity that reflects the turning state of the tractor to follow the target state quantity.
4 . The backward movement control device for the articulated vehicle according to claim 1 , wherein
the tractor includes a sensor that detects a current position of the trailer, and
the one or more processors are further configured to:
generate, based on a target position of the trailer specified through the specific operation and a position of the trailer detected through the sensor, a target trajectory that is an ideal route from the current position of the trailer to the target position,
calculate, based on the position of the trailer detected through the sensor, the target virtual steered angle for causing the trailer to travel along the target trajectory, and
calculate the target steered angle by executing feedback control for causing the virtual steered angle to follow the target virtual steered angle.
5 . The backward movement control device for the articulated vehicle according to claim 1 , wherein
the tractor includes a parking control unit configured to execute an automatic parking function, and
the parking control unit includes:
a first calculation function of calculating, in response to the trailer not being coupled to the tractor, the target steered angle for causing the tractor to travel along a target trajectory, the target trajectory being generated based on a parking space specified by the operator and a position of the tractor; and
a second calculation function of calculating, in response to the trailer being coupled to the tractor, the target steered angle for causing the trailer to travel along a target trajectory generated based on the parking space and a position of the trailer regarded as the rigid vehicle,
the one or more processors are configured to set the target virtual steered angle to the target steered angle and to calculate the target steered angle by executing feedback control for causing the virtual steered angle to follow the set target virtual steered angle, and
in response to the trailer not being coupled to the tractor, the target steered angle calculated through the first calculation function is supplied to the power steering device, whereas in response to the trailer being coupled to the tractor, the target steered angle that is calculated by the one or more processors is supplied to the power steering device.
6 . The backward movement control device for the articulated vehicle according to claim 1 , wherein the one or more processors are configured to execute
a process of calculating the target steered angle by using nonlinear model predictive control, and
a process of assigning a weight to at least one of a following performance of the virtual steered angle with respect to the target virtual steered angle or a state quantity of the tractor.
7 . The backward movement control device for the articulated vehicle according to claim 6 , wherein the state quantity to which a weight is assigned through the process of the one or more processors is at least one of a steered angle of the tractor, a steering angular velocity of the tractor, a yaw rate of the tractor, or a curvature of a movement trajectory of the tractor.
8 . A non-transitory computer-readable medium storing a backward movement control program executed by a backward movement control device including one or more processors for an articulated vehicle, the articulated vehicle including a tractor including steered wheels that change a traveling direction of the articulated vehicle and a trailer towed by the tractor, the tractor being equipped with a power steering device, including a motor, configured to execute feedback control for causing a steered angle of the steered wheels to follow a target steered angle, wherein
the backward movement control program is configured to cause, in response to a backward movement operation of the articulated vehicle being performed, the backward movement control device to execute;
a first process of setting a target virtual steered angle;
a second process of calculating the target steered angle by executing feedback control for causing a virtual steered angle to follow the target virtual steered angle set in the first process; and
a third process of supplying the target steered angle calculated in the second process to the power steering device,
the virtual steered angle is a steered angle of steered wheels that are virtually present in the trailer under an assumption that the trailer is a rigid vehicle separated from the tractor,
the target virtual steered angle is a target value of the virtual steered angle that is set through a specific operation by an operator,
the virtual steered angle is an internal controlled variable of the one or more processors, and
the target steered angle is an output of the feedback control for causing the virtual steered angle to follow the target virtual steered angle.
9 . A backward movement control method for an articulated vehicle, the articulated vehicle including a tractor including steered wheels that change a traveling direction of the articulated vehicle and a trailer towed by the tractor, the tractor being equipped with a power steering device, including a motor, configured to execute feedback control for causing a steered angle of the steered wheels to follow a target steered angle, wherein the backward movement control method comprises:
calculating the target steered angle by executing feedback control for causing a virtual steered angle to follow a target virtual steered angle in response to a backward movement operation of the articulated vehicle being performed, wherein
the virtual steered angle is a steered angle of steered wheels that are virtually present in the trailer under an assumption that the trailer is a rigid vehicle separated from the tractor,
the target virtual steered angle is a target value of the virtual steered angle that is set through a specific operation by an operator,
the virtual steered angle is an internal controlled variable of the backward movement control method, and
the target steered angle is an output of the feedback control for causing the virtual steered angle to follow the target virtual steered angle.
10 . The backward movement control device for the articulated vehicle according to claim 1 , wherein:
the target steered angle is calculated based on a deviation between the virtual steered angle and the target virtual steered angle; and
the target virtual steered angle is directly set by the specific operation of the operator.