Work Machine Speed Control Braking via Grade Force Segmentation
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Solution Overview
Problem
Existing machine control systems fail to automatically and safely decelerate a moving work machine to zero speed across varying grades and load conditions without operator input, risking collisions and brake system wear.
Innovation Solution
A machine equipped with a speed sensor, grade sensor, load sensor, and a controller that determines a total braking force as the sum of grade force, deceleration force, and force correction to control the brake system, ensuring consistent deceleration and safe stopping, regardless of terrain and load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If automatic braking control is implemented to stop the machine safely across varying grades and load conditions, then collision prevention and operational safety are improved, but the system complexity and cost increase due to multiple sensors and controllers
Solution Approach 1:
The braking force is segmented into three distinct components: grade force (to counteract gravitational effects on slopes), deceleration force (to achieve target deceleration rate), and force correction (to compensate for actual vs. target deceleration differences). This segmentation allows each component to be calculated and applied independently, improving control reliability while keeping the overall system manageable through modular force management.
Solution Approach 2:
The system continuously monitors actual deceleration using the speed sensor and compares it to the target deceleration. The deceleration error is fed back to adjust the force correction component of the braking force, creating a closed-loop control system that automatically compensates for variations in grades and loads without requiring complex manual intervention.
2Speed
If braking force is increased to achieve faster stopping, then stopping distance is reduced, but brake system wear and energy loss increase
Solution Approach 1:
The braking force is dynamically adjusted based on real-time operating conditions including grade, load, and actual deceleration performance. The force correction component continuously adapts the braking force to maintain the target deceleration rate, preventing excessive braking that would cause unnecessary wear while ensuring stopping distance requirements are met for each specific condition.
Solution Approach 2:
The system changes the braking force parameters dynamically rather than applying a fixed high braking force. By adjusting the deceleration force and force correction based on measured conditions (grade, load, actual deceleration), the system achieves adequate stopping distance with optimized brake usage, reducing wear and energy loss compared to maximum force braking.
3Stability of the object's composition
If the braking system compensates for grade and load variations, then deceleration consistency is improved, but the computational complexity and control algorithm difficulty increase
Solution Approach 1:
The system calculates the grade force component in advance based on grade sensor data, preparing this compensatory force value before braking is needed. The deceleration force is also predetermined based on the target deceleration rate. These preliminary calculations simplify the real-time control by having pre-computed components ready to be combined with the force correction term.
Solution Approach 2:
The control algorithm segments the total braking force into distinct calculable components: grade force (from grade sensor), deceleration force (from target deceleration and load), and force correction (from deceleration error). Each segment has a clear calculation method, making the overall algorithm more manageable and easier to implement than a single complex unified calculation.
Data Source
AI summary
A machine includes an engine, a brake system, a speed sensor, a grade sensor, a load sensor, and a controller. The controller is configured to: determine a grade force based on the weight of the machine and the grade at which the machine is disposed; determine a deceleration force based on a target deceleration and the weight of the machine; monitor the speed at which the machine is traveling; determine an actual deceleration of the machine based on the monitored speed at which the machine is traveling; determine a deceleration error based on a difference between the actual deceleration and the target deceleration; determine a force correction based on the deceleration error; and control the brake system to apply a total brake force equal to the sum of the grade force, the deceleration force, and the force correction.