Trailer Backup Assist System Jackknife Prevention
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Solution Overview
Problem
Reversing a vehicle while towing a trailer is challenging, especially for unskilled drivers, due to the need for opposite steering inputs and amplified steering errors, and existing trailer backup assist systems are complex, costly, and assume a straight path, failing to account for curved paths and jackknife conditions effectively.
Innovation Solution
A trailer backup assist system that uses a camera to monitor the placement of a target on the trailer, allowing drivers to input desired path curvature through a user-friendly interface, such as a knob or touch screen, and automatically steers the vehicle-trailer combination to maintain the specified path while preventing jackknife conditions by controlling steering and braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a trailer backup assist system assumes a straight path (zero curvature), then the system complexity is reduced, but the system fails to account for curved paths which are common in real-world use cases
Solution Approach 1:
The system dynamically adjusts the assumed path curvature based on detected jackknife conditions rather than assuming a fixed zero-curvature path. When a jackknife condition is detected, the system recognizes that a curved path was likely intended and adjusts control accordingly, allowing the system to adapt between straight and curved path assumptions.
Solution Approach 2:
The system changes the path curvature parameter from a fixed zero value to a dynamic value that accounts for detected jackknife conditions. This parameter change allows the system to handle both straight and curved backup scenarios without requiring complex path planning algorithms.
2Adaptability or versatility
If complex path specification and obstacle detection systems are added to handle curved paths, then the system can accommodate real-world use cases, but the human machine interface becomes relatively complex and costly
Solution Approach 1:
The system uses the trailer's own dynamics and detected jackknife conditions to infer the driver's intended path curvature, eliminating the need for explicit path specification by the driver. The trailer essentially tells the system what path curvature is needed through its physical response to steering inputs.
Solution Approach 2:
The system uses feedback from jackknife condition detection to automatically adjust path curvature assumptions. When a jackknife condition occurs, the system infers that curved path tracking is needed and adjusts control parameters accordingly, creating a closed-loop system that adapts to driver intent without complex HMI.
3Measurement precision
If high precision GPS, cameras, or inertial navigation are used to determine path following accuracy, then the system can accurately detect when the desired goal is met, but the system becomes relatively complex and costly
Solution Approach 1:
The system replaces complex electronic detection systems (GPS, cameras, inertial navigation) with a simpler mechanical/dynamical approach using hitch angle sensors and steering angle sensors to infer path following accuracy and goal achievement through physical parameters rather than visual or positional data.
Solution Approach 2:
The system uses hitch angle and steering angle as intermediary parameters that indirectly indicate path following accuracy and goal achievement, rather than directly measuring position or path deviation. These intermediary measurements provide sufficient information for control purposes without requiring expensive direct measurement systems.
4Ease of operation
If maximum steering input is applied to reduce hitch angle during jackknife condition, then the vehicle can be steered to relieve the jackknife angle, but the vehicle must be pulled forward which is inconvenient and can cause damage if speed and acceleration are not controlled
Solution Approach 1:
The system applies preliminary countermeasures by detecting jackknife conditions early and automatically adjusting steering and braking before the condition worsens. By anticipating the need for recovery action and applying controlled steering and braking inputs, the system prevents the need for aggressive forward pulling that could cause damage.
Solution Approach 2:
The system continuously monitors hitch angle and steering angle to detect jackknife conditions and provides real-time feedback control by adjusting steering and braking inputs. This closed-loop control allows the system to relieve jackknife conditions through controlled maneuvering rather than aggressive forward movement, reducing the risk of vehicle damage.
Data Source
AI summary
A vehicle trailer backup assist system and method includes a hitch angle detection apparatus and a target monitor controller. The target monitor controller processes images acquired of the trailer towed by a towing vehicle to assist with placement of a target on the trailer. The target monitor controller also monitors the target and provides feedback to the user as to proper positioning of the target on the trailer. A target move detection routine detects movement of a target by processing the pixels of the image to determine if a new trailer has been connected. Further, a trailer connection monitoring routine monitors for a changed trailer based on loss of the hitch angle or target for a predetermined time period.