Steering Control Unit Dynamic Load Compensation
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Solution Overview
Problem
Existing electric power steering systems fail to effectively reduce changes in load on the driver due to variations in vehicle weight and load shifts during acceleration or deceleration, affecting steering feel.
Innovation Solution
A steering control unit that adjusts the assist force by compensating for vertical load changes using sensors to detect forces on the steered wheels, increasing assist force when vertical load increases and decreasing it when vertical load decreases, thereby maintaining a consistent steering experience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the assist force is increased to compensate for vehicle weight, then the steering load on the driver is reduced, but the steering feel becomes inconsistent when the number of occupied seats is unchanged but weight varies due to individual weight or baggage
Solution Approach 1:
The patent changes the parameter used for assist force control from a fixed value based on the number of occupied seats to a dynamic parameter based on actual vertical load detection. The vertical load detection device continuously monitors the actual weight on the steered wheel, and the control unit adjusts the assist force according to the detected vertical load, enabling the system to adapt to weight variations caused by individual passenger weights or baggage while maintaining consistent steering feel.
2Ease of operation
If the assist force is adjusted based on the number of occupied seats, then the steering load is reduced for heavier vehicles, but the steering feel changes during acceleration or deceleration due to load shifts
Solution Approach 1:
The patent implements a feedback mechanism where the vertical load detection device continuously monitors the actual vertical load on the steered wheel and feeds this information back to the control unit. The control unit then adjusts the assist force based on the detected vertical load changes, including those caused by acceleration or deceleration. This closed-loop feedback system maintains stable steering feel by dynamically compensating for load shifts during vehicle operation.
3Device complexity
If a fixed assist force is provided based on the number of occupied seats, then the control system is simple, but it cannot compensate for weight variations due to individual weight or baggage
Solution Approach 1:
The patent employs a self-service approach where the vertical load detection device automatically detects the actual weight on the steered wheel, and the control unit autonomously adjusts the assist force based on the detected vertical load. This self-regulating system eliminates the need for complex manual input or pre-programming of weight compensation values, achieving adaptive weight compensation while keeping the control system relatively simple.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces the change in load on the driver by dynamically adjusting the assist force in response to changes in vehicle weight and load shifts, enhancing steering feel and stability.
Implementation Method 1
a bearing device that rotatably supports the steered wheel and that has a sensor for detecting a force applied to the steered wheel
Data Source
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AI summary
A steering control unit (50) includes a microcomputer (51) that controls the driving of a motor (40) on the basis of a steering torque to cause the motor (40) to produce an assist force that is supplied to a steering mechanism (2) as power to steer front wheels (15R,15L). The microcomputer (51) calculates, on the basis of the steering torque, an assist component indicative of the assist force that the motor (40) needs to produce. The microcomputer (51) obtains vertical forces related to the front wheels (15R,15L) that are calculated by hub units (17R,17L) that rotatably support the front wheels (15R,15L)and have front wheel sensors (62R,62L) for detecting forces applied to the front wheels (15R,15L). The microcomputer (51) compensates the assist component by using the obtained vertical forces, to reduce a change in load on a driver that is caused when vertical loads on the front wheels (15R,15L) change.