Trailer Backup Speed Limiting via Grade-Aware Braking
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Solution Overview
Problem
Reversing a vehicle while towing a trailer can be challenging, especially for infrequent drivers, as existing systems struggle to reliably prevent the trailer from converging towards a jackknife angle, particularly at higher speeds.
Innovation Solution
A trailer backup assist system that includes a brake system, throttle sensor module, and control module, which estimates road grade and outputs a brake torque request to maintain vehicle speed below a maximum speed, dynamically adjusting brake torque in response to overspeed conditions and incorporating feed-forward tables to account for road grade and throttle variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the vehicle speed is increased during trailer reversing, then the productivity of the operation is improved, but the reliability of the system in preventing jackknife conditions deteriorates
Solution Approach 1:
The system applies preliminary braking action before the vehicle reaches maximum speed to prevent overspeed conditions. The brake torque request is proactively adjusted based on predicted road grade and current speed, preventing the trailer from converging toward a jackknife angle rather than reacting after the problem occurs.
Solution Approach 2:
The control module performs preliminary calculations of the required brake torque request based on estimated road grade and current vehicle speed. This preliminary action allows the system to prepare appropriate braking force in advance, ensuring reliable speed control and jackknife prevention even at higher reversing speeds.
2Reliability
If the brake torque request is increased to maintain speed control, then the reliability of speed limiting is improved, but the ease of operation deteriorates due to more aggressive braking
Solution Approach 1:
The brake torque request is dynamically adjusted based on real-time vehicle speed, estimated road grade, and throttle position. The control module continuously modifies the braking force to match current operating conditions, providing smooth and adaptive braking that maintains reliability while preserving ease of operation.
Solution Approach 2:
The system uses feedback from the speed sensor and throttle position sensor to continuously monitor vehicle speed and driver input. The control module adjusts the brake torque request based on this feedback, creating a closed-loop control system that maintains reliable speed control while adapting to driver intentions and road conditions for smooth operation.
3Adaptability or versatility
If the system incorporates road grade estimation and dynamic brake adjustment, then the adaptability to different operating conditions is improved, but the device complexity increases
Solution Approach 1:
The control module performs multiple functions using a single integrated system: it estimates road grade based on vehicle speed changes, calculates required brake torque, and controls the braking system. This multi-functional approach provides adaptability to different road grades and operating conditions without requiring separate dedicated systems for each function.
Solution Approach 2:
The system uses existing vehicle sensors (speed sensor, throttle position sensor) and the vehicle's own motion to estimate road grade. Rather than requiring external sensors or complex infrastructure, the control module self-services by utilizing available data and vehicle dynamics to adapt to different operating conditions.
Data Source
AI summary
A trailer backup assist system for a vehicle reversing a trailer includes a brake system and a throttle sensor module outputting a throttle application signal. The system further includes a control module estimating a road grade beneath the trailer and outputting a brake torque request to the brake system based on the estimated road grade and the throttle application signal.